WorldWideScience

Sample records for radiation hardness prediction

  1. CMOS optimization for radiation hardness

    International Nuclear Information System (INIS)

    Derbenwick, G.F.; Fossum, J.G.

    1975-01-01

    Several approaches to the attainment of radiation-hardened MOS circuits have been investigated in the last few years. These have included implanting the SiO 2 gate insulator with aluminum, using chrome-aluminum layered gate metallization, using Al 2 O 3 as the gate insulator, and optimizing the MOS fabrication process. Earlier process optimization studies were restricted primarily to p-channel devices operating with negative gate biases. Since knowledge of the hardness dependence upon processing and design parameters is essential in producing hardened integrated circuits, a comprehensive investigation of the effects of both process and design optimization on radiation-hardened CMOS integrated circuits was undertaken. The goals are to define and establish a radiation-hardened processing sequence for CMOS integrated circuits and to formulate quantitative relationships between process and design parameters and the radiation hardness. Using these equations, the basic CMOS design can then be optimized for radiation hardness and some understanding of the basic physics responsible for the radiation damage can be gained. Results are presented

  2. Impact of aging on radiation hardness

    International Nuclear Information System (INIS)

    Shaneyfelt, M.R.; Winokur, P.S.; Fleetwood, D.M.

    1997-01-01

    Burn-in effects are used to demonstrate the potential impact of thermally activated aging effects on functional and parametric radiation hardness. These results have implications on hardness assurance testing. Techniques for characterizing aging effects are proposed

  3. Development of radiation hard scintillators

    International Nuclear Information System (INIS)

    Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G.; Blackburn, R.

    1992-05-01

    Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro

  4. Radiation-Hard Quartz Cerenkov Calorimeters

    International Nuclear Information System (INIS)

    Akgun, U.; Onel, Y.

    2006-01-01

    New generation hadron colliders are going to reach unprecedented energies and radiation levels. Quartz has been identified as a radiation-hard material that can be used for Cerenkov calorimeters of the future experiments. We report from the radiation hardness tests performed on quartz fibers, as well as the characteristics of the quartz fiber and plate Cerenkov calorimeters that have been built, designed, and proposed for the CMS experiment

  5. Radiation hard memory cell and array thereof

    International Nuclear Information System (INIS)

    Gunckel, T.L. II; Rovell, A.; Nielsen, R.L.

    1978-01-01

    A memory cell configuration that is implemented to be relatively hard to the adverse effects of a nuclear event is discussed. The presently disclosed memory cell can be interconnected with other like memory cells to form a high speed radiation hard register file. Information is selectively written into and read out of a memory cell comprising the register file, which memory cell preserves previously stored data without alteration in the event of exposure to high levels of nuclear radiation

  6. Radiation hardness of undoped BGO crystals

    International Nuclear Information System (INIS)

    Sahu, S.K.; Peng, K.C.; Huang, H.C.; Wang, C.H.; Chang, Y.H.; Hou, W.S.; Ueno, K.; Chou, F.I.; Wei, Y.Y.

    1997-01-01

    We measured the radiation hardness of undoped BGO crystals from two different manufacturers. Such crystals are proposed to be used in a small-angle calorimeter of the BELLE detector of the KEK B-factory. Transparency and scintillation light output of the crystals were monitored to see the effect of radiation damage. The crystals show considerable radiation hardness up to 10.2 Mrad equivalent dose, which is much higher than the maximum expected dosage of 500 krad per year of running at BELLE. (orig.)

  7. Radiation hard cryogenic silicon detectors

    International Nuclear Information System (INIS)

    Casagrande, L.; Abreu, M.C.; Bell, W.H.; Berglund, P.; Boer, W. de; Borchi, E.; Borer, K.; Bruzzi, M.; Buontempo, S.; Chapuy, S.; Cindro, V.; Collins, P.; D'Ambrosio, N.; Da Via, C.; Devine, S.; Dezillie, B.; Dimcovski, Z.; Eremin, V.; Esposito, A.; Granata, V.; Grigoriev, E.; Hauler, F.; Heijne, E.; Heising, S.; Janos, S.; Jungermann, L.; Konorov, I.; Li, Z.; Lourenco, C.; Mikuz, M.; Niinikoski, T.O.; O'Shea, V.; Pagano, S.; Palmieuri, V.G.; Paul, S.; Pirollo, S.; Pretzl, K.; Rato, P.; Ruggiero, G.; Smith, K.; Sonderegger, P.; Sousa, P.; Verbitskaya, E.; Watts, S.; Zavrtanik, M.

    2002-01-01

    It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, 'resuscitate' when operated at temperatures below 130 K. This is often referred to as the 'Lazarus effect'. The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors

  8. Radiation hardness assurances categories for COTS technologies

    International Nuclear Information System (INIS)

    Hash, G.L.; Shaneyfelt, M.R.; Sexton, F.W.; Winokur, P.S.

    1997-01-01

    A comparison of the radiation tolerance of three commercial, and one radiation hardened SRAM is presented for four radiation environments. This work has shown the difficulty associated with strictly categorizing a device based solely on its radiation response, since its category depends on the specific radiation environment considered. For example, the 3.3-V Paradigm SRAM could be considered a radiation-tolerant device except for its SEU response. A more useful classification depends on the methods the manufacturer uses to ensure radiation hardness, i.e. whether specific design and process techniques have been used to harden the device. Finally, this work has shown that burned-in devices may fail functionally as much as 50% lower in total dose environments than non-burned-in devices. No burn-in effect was seen in dose-rate upset, latchup, or SEE environments. The user must ensure that total dose lot acceptance testing was performed on burned-in devices

  9. Optical fiber composition and radiation hardness

    International Nuclear Information System (INIS)

    Wall, J.A.; Loretz, T.J.

    1982-01-01

    Germanium phosphosilicate and germanium borosilicate fibers doped with cerium were fabricated and tested for their responses to steady-state Co-60 radiation at -55 C, +20 C and +125 C. A fiber with germanium, boron and phosphorous in the silicate core and doped with antimony in the core and clad was similarly tested. All of the fibers showed significant improvements in radiation hardness at 20 C compared to undoped fibers of the same base composition. At -55 C, however, all except the cerium doped germanium phosphosilicate were very radiation sensitive and also showed increases in the rate of induced loss at +125 C. The cerium doped germanium phosphosilicate fiber showed virtually no change in radiation sensitivity at the temperature extremes and could prove useful in applications requiring relatively short lengths of fiber

  10. Radiation hardness of CMS pixel barrel modules

    CERN Document Server

    Rohe, T; Erdmann, W; Kästli, H C; Khalatyan, S; Meier, B; Radicci, V; Sibille, J

    2010-01-01

    Pixel detectors are used in the innermost part of the multi purpose experiments at LHC and are therefore exposed to the highest fluences of ionising radiation, which in this part of the detectors consists mainly of charged pions. The radiation hardness of all detector components has thoroughly been tested up to the fluences expected at the LHC. In case of an LHC upgrade, the fluence will be much higher and it is not yet clear how long the present pixel modules will stay operative in such a harsh environment. The aim of this study was to establish such a limit as a benchmark for other possible detector concepts considered for the upgrade. As the sensors and the readout chip are the parts most sensitive to radiation damage, samples consisting of a small pixel sensor bump-bonded to a CMS-readout chip (PSI46V2.1) have been irradiated with positive 200 MeV pions at PSI up to 6E14 Neq and with 21 GeV protons at CERN up to 5E15 Neq. After irradiation the response of the system to beta particles from a Sr-90 source w...

  11. Radiation hardness of CMS pixel barrel modules

    International Nuclear Information System (INIS)

    Rohe, T.; Bean, A.; Erdmann, W.; Kaestli, H.-C.; Khalatyan, S.; Meier, B.; Radicci, V.; Sibille, J.

    2010-01-01

    Pixel detectors are used in the innermost part of the multi purpose experiments at the LHC and are therefore exposed to the highest fluences of ionising radiation, which in this part of the detectors consists mainly of charged pions. The radiation hardness of all detector components has been thoroughly tested up to the fluences expected at the LHC. In case of an LHC upgrade, the fluence will be much higher and it is not yet clear how long the present pixel modules will stay operative in such a harsh environment. The aim of this study was to establish such a limit as a benchmark for other possible detector concepts considered for the upgrade. As the sensors and the readout chip are the parts most sensitive to radiation damage, samples consisting of a small pixel sensor bump-bonded to a CMS-readout chip (PSI46V2.1) have been irradiated with positive 200 MeV pions at PSI up to 6x10 14 n eq /cm 2 and with 21 GeV protons at CERN up to 5x10 15 n eq /cm 2 . After irradiation the response of the system to beta particles from a 90 Sr source was measured to characterise the charge collection efficiency of the sensor. Radiation induced changes in the readout chip were also measured. The results show that the present pixel modules can be expected to be still operational after a fluence of 2.8x10 15 n eq /cm 2 . Samples irradiated up to 5x10 15 n eq /cm 2 still see the beta particles. However, further tests are needed to confirm whether a stable operation with high particle detection efficiency is possible after such a high fluence.

  12. Radiation hardness of WLS fibres for the ATLAS Tile Calorimeter

    CERN Document Server

    David, M; Maio, A

    2007-01-01

    In this document we present the data obtained in the irradiation in a Co-60 source of WLS fibers for the TileCal calorimeter. The optical, mechanical and radiation hardness properties of these fibers were developed in close contact with three producers: Bicron, Kuraray and Pol.Hi.Tech. The results on the degradation of the light output and attenuation length from five irradiations are presented. The fibers were irradiated with a total dose at least 3 times higher than the dose predicted for 10 years of operation of LHC at nominal luminosity.

  13. Radiation hard solar cell and array

    International Nuclear Information System (INIS)

    Russell, R.L.

    1975-01-01

    A power generating solar cell for a spacecraft solar array is hardened against transient response to nuclear radiation while permitting normal operation of the cell in a solar radiation environment by shunting the cell with a second solar cell whose contacts are reversed relative to the power cell to form a cell module, exposing the power cell only to the solar radiation in a solar radiation environment to produce an electrical output at the module terminals, and exposing both cells to the nuclear radiation in a nuclear radiation environment so that the radiation induced currents generated by the cells suppress one another

  14. Radiation hardness of new Kuraray double cladded optical fibers

    International Nuclear Information System (INIS)

    Bedeschi, F.; Menzione, A.; Budagov, Yu.; Chirikov-Zorin, I.; Solov'ev, A.; Turchanovich, L.; Vasil'chenko, V.

    1996-01-01

    The radiation hardness of the new plastic scintillating and clear fibers irradiated by 137 Cs γ-flux and by pulsed reactor fast neutrons were investigated. All the studied fibers were of S-type (with S=70) and had a double cladding. Optical fibers degradation study after irradiation shows that the level of radiation hardness lower that what is expected from results of previous studies. 9 refs., 6 figs

  15. Radiation hard diamond sensors for future tracking applications

    International Nuclear Information System (INIS)

    Adam, W.; Boer, W. de; Borchi, E.

    2006-01-01

    Progress in experimental particle physics in the coming decade depends crucially upon the ability to carry out experiments in high-radiation areas. In order to perform these complex and expensive experiments, new radiation hard technologies must be developed. This paper discusses the use of diamond detectors in future tracking applications and their survivability in the highest radiation environments. We present results of devices constructed with the newest polycrystalline and single crystal Chemical Vapor Deposition diamond and their tolerance to radiation

  16. Radiation hard silicon microstrip detectors for Tevatron experiments

    International Nuclear Information System (INIS)

    Korjenevski, Sergey

    2004-01-01

    The Silicon Microstrip Tracking detectors at the CDF and D0 experiments have now been operating for almost three years at Fermilab. These detectors were designed originally for an integrated luminosity of 2fb -1 . As the expected luminosity for Run IIb at the Tevatron collider was initially envisioned to reach 15fb -1 , radiation tolerances of both devices were revisited, culminating in proposals for new systems. With reduced expectations for total luminosity at ∼6fb -1 , the full detector-replacement projects were terminated. The CDF detector is expected nevertheless to cope efficiently with the lower anticipated dose, however, the D0 experiment is planning a smaller-scale project: a Layer-0 (L0) upgrade of the silicon tracker (D0SMT). The new device will fit between the beam line and the inner layer of the current Tracker. Built of single-sided sensors, this upgrade is expected to perform well in the harsh radiation environment, and be able to withstand an integrated luminosity of 15fb -1 . Prototypes of Run IIb sensors were irradiated using 10MeV protons at the tandem Van de Graaff at the James R. McDonald Laboratory at Kansas State University. A fit to the 10MeV proton data yields a damage parameter αp=11x10-17Acm. This is consistent with results from RD48 (αp=9.9x10-17Acm). The scaling of damage to 1MeV neutron fluence uses a hardness factor (κ) derived from the non-ionizing components of the energy loss (NEIL). NEIL predicts a hardness factor of 3.87 for 10MeV protons. We obtained an experimental value of this factor of 2.54, or 34% smaller than scaling predictions from NEIL

  17. Radiation hardness studies for DEPFETs in Belle II

    International Nuclear Information System (INIS)

    Ritter, Andreas

    2014-01-01

    The study of CP violation requires dedicated detectors and accelerators. At KEK, the High Energy Accelerator Research Organization located in Tsukuba, Japan, an upgrade of the present accelerator KEKB and its detector is in progress. For this new Belle II detector, a new vertex system will be installed, consisting of a silicon strip detector (SVD) and a pixel detector (PXD). The PXD exhibits eight million pixels, each of them made of Depleted p-channel Field Effect Transistors (DEPFETs). During the operation of Belle II various machine- as well as luminosity-related background processes affect the device performance of the DEPFET through radiation damage. As a Metal-Oxide-Semiconductor (MOS) device, the DEPFET is affected by ionizing radiation damage as well as by damages to the silicon bulk itself. The major part of the radiation damage has its origin in the creation of electrons and positrons near the interaction point. Therefore, the hardness factor of electrons of relevant energy was investigated in this work. With this quantity the damage by electrons could be compared to the damage inflicted by neutrons. Neutron irradiations were performed with DEPFETs and related silicon material. The effects of leakage current increase and type inversion were studied. As the electron hardness investigation indicates, the bulk damage done to the DEPFET is small in comparison to the impact on the silicon dioxide layer of the device. Ionizing radiation results in a build-up of oxide charge, thus changing the device characteristics. Especially the threshold voltage of the DEPFET is shifted to more negative values. This shift has to be compensated during the operation of Belle II and is limited by device and system constraints, thus an overall small shift is desired. The changes in the device characteristics were investigated for the two gate electrodes of the DEPFET with respect to their biasing and production related issues. With an additional layer of silicon nitride and a

  18. Sustainably Sourced, Thermally Resistant, Radiation Hard Biopolymer

    Science.gov (United States)

    Pugel, Diane

    2011-01-01

    This material represents a breakthrough in the production, manufacturing, and application of thermal protection system (TPS) materials and radiation shielding, as this represents the first effort to develop a non-metallic, non-ceramic, biomaterial-based, sustainable TPS with the capability to also act as radiation shielding. Until now, the standing philosophy for radiation shielding involved carrying the shielding at liftoff or utilizing onboard water sources. This shielding material could be grown onboard and applied as needed prior to different radiation landscapes (commonly seen during missions involving gravitational assists). The material is a bioplastic material. Bioplastics are any combination of a biopolymer and a plasticizer. In this case, the biopolymer is a starch-based material and a commonly accessible plasticizer. Starch molecules are composed of two major polymers: amylase and amylopectin. The biopolymer phenolic compounds are common to the ablative thermal protection system family of materials. With similar constituents come similar chemical ablation processes, with the potential to have comparable, if not better, ablation characteristics. It can also be used as a flame-resistant barrier for commercial applications in buildings, homes, cars, and heater firewall material. The biopolymer is observed to undergo chemical transformations (oxidative and structural degradation) at radiation doses that are 1,000 times the maximum dose of an unmanned mission (10-25 Mrad), indicating that it would be a viable candidate for robust radiation shielding. As a comparison, the total integrated radiation dose for a three-year manned mission to Mars is 0.1 krad, far below the radiation limit at which starch molecules degrade. For electron radiation, the biopolymer starches show minimal deterioration when exposed to energies greater than 180 keV. This flame-resistant, thermal-insulating material is non-hazardous and may be sustainably sourced. It poses no hazardous

  19. Development of radiation hardness components for ITER remote maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi; Ito, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yagi, Toshiaki; Morita, Yousuke

    1998-04-01

    In the ITER, in-vessel remote handling is required to assemble and maintain in-vessel components in DT operations. Since in-vessel remote handling systems must operate under intense gamma ray radiation exceeding 30 kGy/h, their components must have sufficiently high radiation hardness to allow maintenance long enough in ITER in-vessel environments. Thus, extensive radiation tests and quality improvement, including optimization of material compositions, have been conducted through the ITER R and D program to develop radiation hardness components that meet radiation doses from 10 to 100 MGy at 10 kGy/h. This paper presents the latest on radiation hardness component development conducted by the Japan Home Team as a contribution to the ITER. The remote handling components tested are categorized for use in robotic or viewing systems, or as common components. Radiation tests have been conducted on commercially available products for screening, on modified products, and on new products to improve the radiation hardness. (author)

  20. Development of radiation hardness components for ITER remote maintenance

    International Nuclear Information System (INIS)

    Obara, Kenjiro; Kakudate, Satoshi; Oka, Kiyoshi; Ito, Akira; Yagi, Toshiaki; Morita, Yousuke

    1998-01-01

    In the ITER, in-vessel remote handling is required to assemble and maintain in-vessel components in DT operations. Since in-vessel remote handling systems must operate under intense gamma ray radiation exceeding 30 kGy/h, their components must have sufficiently high radiation hardness to allow maintenance long enough in ITER in-vessel environments. Thus, extensive radiation tests and quality improvement, including optimization of material compositions, have been conducted through the ITER R and D program to develop radiation hardness components that meet radiation doses from 10 to 100 MGy at 10 kGy/h. This paper presents the latest on radiation hardness component development conducted by the Japan Home Team as a contribution to the ITER. The remote handling components tested are categorized for use in robotic or viewing systems, or as common components. Radiation tests have been conducted on commercially available products for screening, on modified products, and on new products to improve the radiation hardness. (author)

  1. Testing the radiation hardness of lead tungstate scintillating crystals

    CERN Document Server

    Shao, M; Li Chuan; Chen, H; Xu, Z Z; Wang, Z M

    2000-01-01

    Large Hadron Collider operation will produce a high radiation background. PbWO/sub 4/ crystals are selected as scintillators for the CMS electromagnetic calorimeter. To reach the precise requirement for energy measurements, a strict requirement for the radiation hardness is needed. In this paper, we present a method for evaluating the radiation hardness and its measurement. Results for several full size (23 cm length) lead tungstate crystals under Co/sup 60/ gamma - ray irradiation are given, investigating the light yield loss and its longitudinal uniformity. (8 refs).

  2. Hard facts for radiation curing of elastomers

    International Nuclear Information System (INIS)

    Lyall, D.J.

    1984-01-01

    The subject is covered under the headings: introduction; outline of chemistry (differences between conventional and radiation curing); compounding; green strength; response of rubbers to electron beam treatment; electron beam cured applications:(a) wire and cable applications;(b) rubber tyre components;(c) heat shrinkable materials;(d) roofing materials. (U.K.)

  3. Development of radiation hard components for remote maintenance

    International Nuclear Information System (INIS)

    Oka, Kiyoshi; Obara, Kenjiro; Kakudate, Satoshi; Tominaga, Ryuichiro; Akada, Tamio; Morita, Hirosuke.

    1997-01-01

    In International Thermonuclear Experimental Reactor (ITER), in-vessel remote-handling is inevitably required to assemble and maintain activated in-vessel components due to D-T operation. The components of the in-vessel remote-handling system must have sufficient radiation hardness to allow for operation under an intense gamma-ray radiation of over 30 kGy/h for periods up to more than 1,000 hours. To this end, extensive irradiation tests and quality improvements including the optimization of material composition have been conducted through the ITER R and D program in order to develop radiation hard components which satisfy radiation doses from 10 MGy to 100 MGy at the dose rate of 10 kGy/h. This paper outlines the latest status of the radiation hard component development that has been conducted as the Japan Home Team's contribution to ITER. The remote-handling components tested are categorized into either robotics, viewing systems or common components. The irradiation tests include commercial base products for screening both modified and newly developed products to improve their radiation hardness. (author)

  4. BaYb2F8, a new radiation hard Cherenkov radiator for electromagnetic calorimeters

    International Nuclear Information System (INIS)

    Aseev, A.A.; Devitsin, E.G.; Komar, A.A.; Kozlov, V.A.; Hovsepyan, Yu.I.; Potashov, S.Yu.; Sokolovsky, K.A.; Uvarova, T.V.; Vasilchenko, V.G.

    1992-01-01

    Radiation hardness and optical properties of a new Cherenkov radiator, heavy fluoride BaYb 2 F 8 doped with various elements, have been studied. The above mentioned crystal has the density of 7 g/cm 3 , the radiation length is 1.28 cm and the Moliere radius 2.44 cm. High radiation hardness has been demonstrated for BaYb 2 F 8 doped with Tm, Pr, Tb. (orig.)

  5. The transient radiation effects and hardness of programmed device

    International Nuclear Information System (INIS)

    Du Chuanhua; Xu Xianguo; Zhao Hailin

    2014-01-01

    A review and summary of research and development in the investigation of transient ionizing radiation effects in device and cirviut is presented. The transient ionizing radiation effects in two type of programmed device, that's 32 bit Microcontroller and antifuse FPGA, were studied. The expeiment test data indicate: The transient ionizing radiation effects of 32 bit Microcontroller manifested self-motion restart and Latchup, the Latchup threshold was 5 × 10"7 Gy (Si)/s. The transient ionizing radiation effects of FPGA was reset, no Latchup. The relationship of circuit effects to physical mechanisms was analized. A new method of hardness in circiut design was put forward. (authors)

  6. Capillary discharge sources of hard UV radiation

    International Nuclear Information System (INIS)

    Cachoncinlle, C; Dussart, R; Robert, E; Goetze, S; Pons, J; Mohanty, S R; Viladrosa, R; Fleurier, C; Pouvesle, J M

    2002-01-01

    We developed and studied three different extreme ultraviolet (EUV) capillary discharge sources either dedicated to the generation of coherent or incoherent EUV radiation. The CAPELLA source has been developed especially as an EUV source for the metrology at 13.4 nm. With one of these sources, we were able to produce gain on the Balmer-Hα (18.22 nm) and Hβ (13.46 nm) spectral lines in carbon plasma. By injecting 70 GW cm -3 we measured gain-length products up to 1.62 and 3.02 for the Hα and Hβ, respectively optimization of the EUV capillary source CAPELLA led to the development of an EUV lamp which emits 2 mJ in the bandwidth of the MoSi mirror, per joule stored, per shot and in full solid angle. The wall-plug efficiency is 0.2%. Stability of this lamp is better than 4% and the lamp can operate at repetition rate of 50 Hz

  7. Radiation hardness of diamond and silicon sensors compared

    CERN Document Server

    de Boer, Wim; Furgeri, Alexander; Mueller, Steffen; Sander, Christian; Berdermann, Eleni; Pomorski, Michal; Huhtinen, Mika

    2007-01-01

    The radiation hardness of silicon charged particle sensors is compared with single crystal and polycrystalline diamond sensors, both experimentally and theoretically. It is shown that for Si- and C-sensors, the NIEL hypothesis, which states that the signal loss is proportional to the Non-Ionizing Energy Loss, is a good approximation to the present data. At incident proton and neutron energies well above 0.1 GeV the radiation damage is dominated by the inelastic cross section, while at non-relativistic energies the elastic cross section prevails. The smaller inelastic nucleon-Carbon cross section and the light nuclear fragments imply that at high energies diamond is an order of magnitude more radiation hard than silicon, while at energies below 0.1 GeV the difference becomes significantly smaller.

  8. UV radiation hardness of silicon inversion layer solar cells

    International Nuclear Information System (INIS)

    Hezel, R.

    1990-01-01

    For full utilization of the high spectral response of inversion layer solar cells in the very-short-wavelength range of the solar spectrum sufficient ultraviolet-radiation hardness is required. In addition to the charge-induced passivation achieved by cesium incorporation into the silicon nitride AR coating, in this paper the following means for further drastic reduction of UV light-induced effects in inversion layer solar cells without encapsulation are introduced and interpretations are given: increasing the nitride deposition temperature, silicon surface oxidation at low temperatures, and texture etching and using higher substrate resistivities. High UV radiation tolerance and improvement of the cell efficiency could be obtained simultaneously

  9. RD50 Collaboration overview: Development of new radiation hard detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kuehn, S., E-mail: susanne.kuehn@cern.ch

    2016-07-11

    Silicon sensors are widely used as tracking detectors in high energy physics experiments. This results in several specific requirements like radiation hardness and granularity. Therefore research for highly performing silicon detectors is required. The RD50 Collaboration is a CERN R&D collaboration dedicated to the development of radiation hard silicon devices for application in high luminosity collider experiments. Extensive research is ongoing in different fields since 2001. The collaboration investigates both defect and material characterization, detector characterization, the development of new structures and full detector systems. The report gives selected results of the collaboration and places an emphasis on the development of new structures, namely 3D devices, CMOS sensors in HV technology and low gain avalanche detectors. - Highlights: • The RD50 Collaboration is a CERN R&D collaboration dedicated to the development of radiation hard silicon devices for high luminosity collider experiments. • The collaboration investigates defect, material and detector characterization, the development of new structures and full detector systems. • Results of measured data of n-in-p type sensors allow recommendations for silicon tracking detectors at the HL-LHC. • The charge multiplication effect was investigated to allow its exploitation and resulted in new structures like LGAD sensors. • New sensor types like slim and active edge sensors, 3D detectors, and lately HVCMOS devices were developed in the active collaboration.

  10. Development of ITER diagnostics: Neutronic analysis and radiation hardness

    Energy Technology Data Exchange (ETDEWEB)

    Vukolov, Konstantin, E-mail: vukolov_KY@nrcki.ru; Borisov, Andrey; Deryabina, Natalya; Orlovskiy, Ilya

    2015-10-15

    Highlights: • Problems of ITER diagnostics caused by neutron radiation from hot DT plasma considered. • Careful neutronic analysis is necessary for ITER diagnostics development. • Effective nuclear shielding for ITER diagnostics in the 11th equatorial port plug proposed. • Requirements for study of radiation hardness of diagnostic elements defined. • Results of optical glasses irradiation tests in a fission reactor given. - Abstract: The paper is dedicated to the problems of ITER diagnostics caused by effects of radiation from hot DT plasma. An effective nuclear shielding must be arranged in diagnostic port plugs to meet the nuclear safety requirements and to provide reliable operation of the diagnostics. This task can be solved with the help of neutronic analysis of the diagnostics environment within the port plugs at the design stage. Problems of neutronic calculations are demonstrated for the 11th equatorial port plug. The numerical simulation includes the calculations of neutron fluxes in the port-plug and in the interspace. Options for nuclear shielding, such as tungsten collimator, boron carbide and water moderators, stainless steel and lead screens are considered. Data on neutron fluxes along diagnostic labyrinths allow to define radiation hardness requirements for the diagnostic components and to specify their materials. Options for windows and lenses materials for optical diagnostics are described. The results of irradiation of flint and silica glasses in nuclear reactor have shown that silica KU-1 and KS-4V retain transparency in visible range after neutron fluence of 10{sup 17} cm{sup −2}. Flints required for achromatic objectives have much less radiation hardness about 5 × 10{sup 14} n/cm{sup 2}.

  11. Prediction of hardness in pieces of quenched and tempered steel

    International Nuclear Information System (INIS)

    Yanzon, Rodolfo Carlos; Rodriguez, Augusto; Sanchez, Arlington Ricardo

    2006-01-01

    This presentation describes the first stage of a work plan to obtain a simple software, for predicting properties at certain points of a quenched and tempered piece. In this first stage, this prediction is limited to cylindrical pieces made with steels whose chemical composition is within a certain range. The methodology basically consists of obtaining , from experimental data, a mathematical tool able to predict the hardness value, for Jominy test piece ends made with this type of steel. This meant beginning with the analysis of the usual forms of theoretical calculation of Jominy curves of quenched samples, which resulted in a proposal to modify the Just equation. Two different mathematical methods were then developed, that could predict hardness values in tempered Jominy test pieces. One, based on the determination of polynomic equations, that reproduces the loss of hardness at points along the test piece, base on the quenching value and as a function of the tempering temperature. The other one, which uses the lineal multidimensional interpolation method, because of its ease of application, has been selected as the mathematical tool to use in the software under development. At this stage of the work, the relationship between the points on the piece and those on the Jominy test pieces is carried out by the Lamont method and the representative variable of the temperature/time combination for the tempering process itself, is obtained with software based on the Hollomon and Jaffe expression. Data is needed to define: a) chemical composition and grain size of the steel used, b) diameter of the piece, c) 'H G ' severity of the quenching medium d) temperature and time of the tempering. The work's second stage continued with the addition of hardness values measured in Jominy test pieces made with other steels. The chemical composition and grain size data of each steel introduced are converted by the software into one more variable, using the concept of ideal critical

  12. Luck is Hard to Beat: The Difficulty of Sports Prediction

    OpenAIRE

    Aoki, Raquel YS; Assuncao, Renato M; de Melo, Pedro OS Vaz

    2017-01-01

    Predicting the outcome of sports events is a hard task. We quantify this difficulty with a coefficient that measures the distance between the observed final results of sports leagues and idealized perfectly balanced competitions in terms of skill. This indicates the relative presence of luck and skill. We collected and analyzed all games from 198 sports leagues comprising 1503 seasons from 84 countries of 4 different sports: basketball, soccer, volleyball and handball. We measured the competi...

  13. Radiation hardness of superconducting magnet insulation materials for FAIR

    International Nuclear Information System (INIS)

    Seidl, Tim

    2013-03-01

    This thesis focuses on radiation degradation studies of polyimide, polyepoxy/glass-fiber composites and other technical components used, for example, in the superconducting magnets of new ion accelerators such as the planned International Facility for Antiproton and Ion Research (FAIR) at the GSI Helmholtz Center of Heavy Ion Research (GSI) in Darmstadt. As accelerators are becoming more powerful, i.e., providing larger energies and beam intensities, the potential risk of radiation damage to the components increases. Reliable data of the radiation hardness of accelerator materials and components concerning electrical, thermal and other technical relevant properties are of great interest also for other facilities such as the Large Hadron Collider (LHC) of CERN. Dependent on the position of the different components, induced radiation due to beam losses consists of a cocktail of gammas, neutrons, protons, and heavier particles. Although the number of heavy fragments of the initial projectiles is small compared to neutrons, protons, or light fragments (e.g. ? particles), their large energy deposition can induce extensive damage at rather low fluences (dose calculations show that the contribution of heavy ions to the total accumulated dose can reach 80 %). For this reason, defined radiation experiments were conducted using different energetic ion beams (from protons to uranium) and gamma radiation from a Co-60 source. The induced changes were analyzed by means of in-situ and ex-situ analytical methods, e.g. ultraviolet-visible and infrared spectroscopy, residual gas analysis, thermal gravimetric analysis, dielectric strength measurements, measurements of low temperature thermal properties, and performance tests. In all cases, the radiation induces a change in molecular structure as well as loss of functional material properties. The amount of radiation damage is found to be sensitive to the used type of ionizing radiation and the long term stability of the materials is

  14. Radiation-hard/high-speed parallel optical links

    Energy Technology Data Exchange (ETDEWEB)

    Gan, K.K., E-mail: gan@mps.ohio-state.edu [Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Buchholz, P.; Heidbrink, S. [Fachbereich Physik, Universität Siegen, Siegen (Germany); Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S. [Department of Physics, The Ohio State University, Columbus, OH 43210 (United States); Vogt, M.; Ziolkowski, M. [Fachbereich Physik, Universität Siegen, Siegen (Germany)

    2016-09-21

    We have designed and fabricated a compact parallel optical engine for transmitting data at 5 Gb/s. The device consists of a 4-channel ASIC driving a VCSEL (Vertical Cavity Surface Emitting Laser) array in an optical package. The ASIC is designed using only core transistors in a 65 nm CMOS process to enhance the radiation-hardness. The ASIC contains an 8-bit DAC to control the bias and modulation currents of the individual channels in the VCSEL array. The performance of the optical engine up at 5 Gb/s is satisfactory.

  15. Study of the Radiation-Hardness of VCSEL and PIN

    CERN Document Server

    Gan, K K; Fernando, W; Kagan, H P; Kass, R D; Lebbai, M R M; Merritt, H; Moore, J R; Nagarkar, A; Rizatdinova, F; Skubic, P L; Smith, D S; Strang, M

    2009-01-01

    The silicon trackers of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN (Geneva) use optical links for data transmission. An upgrade of the trackers is planned for the Super LHC (SLHC), an upgraded LHC with ten times higher luminosity. We study the radiation-hardness of VCSELs (Vertical-Cavity Surface-Emitting Laser) and GaAs and silicon PINs using 24 GeV/c protons at CERN for possible application in the data transmission upgrade. The optical power of VCSEL arrays decreases significantly after the irradiation but can be partially annealed with high drive currents. The responsivities of the PIN diodes also decrease significantly after irradiation, but can be recovered by operating at higher bias voltage. This provides a simple mechanism to recover from the radiation damage.

  16. Prototype for a Radiation Hard Upgrade to the ATLAS ZDC

    CERN Document Server

    Phipps, Michael William; The ATLAS collaboration

    2017-01-01

    Increases in luminosity and collision energy at the LHC challenge the radiation hardness of detectors located along the beamline. This problem is especially acute for the Zero Degree Calorimeters (ZDCs) in ATLAS, which are exposed to around 10^{10} rad/yr, rendering the current version of the detector inviable during p+p running. To address this shortcoming and allow for important triggers and potential access to low-x physics, we designed a prototype detector that replaces quartz radiator material with a circulating, liquid hydrocarbon. It also features a dual-stage wavelength shifting scheme to transport light to silicon photo-multipliers, as well as both transverse and longitudinal segmentation to study the shower development in two dimensions. Design considerations, results from an SPS beam test and comparisons to GEANT simulation will be presented.

  17. Studies of radiation hardness of MOS devices for application in a linear collider vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Qingyu

    2008-10-17

    The proposed International Linear Collider (ILC) together with the Large Hadron Collider (LHC) at CERN serve as a combined tool to explore the mysteries of the universe: the former is a precision machine and the latter can be considered as a finding machine. The key component of the ILC is the vertex detector that should be placed as close as possible to the Interaction Point (IP) and has better radiation tolerance against the dominant electron-positron pair production background from beam-beam interactions. A new generation of MOS-type Depleted-Field-Effect Transistor (MOSDEPFET) active pixel detectors has been proposed and developed by Semiconductor Labor Munich for Physics and for extraterrestrial Physics in order to meet the requirements of the vertex detector at the ILC. Since all MOS devices are susceptible to ionizing radiation, the main topic is focused on the radiation hardness of detectors, by which a series of physical processes are analyzed: e.g. surface damage due to ionizing radiation as well as damage mechanisms and their associated radiation effects. As a consequence, the main part of this thesis consists of a large number of irradiation experiments and the corresponding discussions. Finally, radiation hardness of the detectors should be improved through a set of concluded experiences that are based on a series of analysis of the characteristic parameters using different measurement techniques. The feasibility of the MOSDEPFET-based vertex detector is, therefore, predicted at ILC. (orig.)

  18. Studies of radiation hardness of MOS devices for application in a linear collider vertex detector

    International Nuclear Information System (INIS)

    Wei, Qingyu

    2008-01-01

    The proposed International Linear Collider (ILC) together with the Large Hadron Collider (LHC) at CERN serve as a combined tool to explore the mysteries of the universe: the former is a precision machine and the latter can be considered as a finding machine. The key component of the ILC is the vertex detector that should be placed as close as possible to the Interaction Point (IP) and has better radiation tolerance against the dominant electron-positron pair production background from beam-beam interactions. A new generation of MOS-type Depleted-Field-Effect Transistor (MOSDEPFET) active pixel detectors has been proposed and developed by Semiconductor Labor Munich for Physics and for extraterrestrial Physics in order to meet the requirements of the vertex detector at the ILC. Since all MOS devices are susceptible to ionizing radiation, the main topic is focused on the radiation hardness of detectors, by which a series of physical processes are analyzed: e.g. surface damage due to ionizing radiation as well as damage mechanisms and their associated radiation effects. As a consequence, the main part of this thesis consists of a large number of irradiation experiments and the corresponding discussions. Finally, radiation hardness of the detectors should be improved through a set of concluded experiences that are based on a series of analysis of the characteristic parameters using different measurement techniques. The feasibility of the MOSDEPFET-based vertex detector is, therefore, predicted at ILC. (orig.)

  19. Using Neural Networks to Predict the Hardness of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    B. Zahran

    2015-02-01

    Full Text Available Aluminum alloys have gained significant industrial importance being involved in many of the light and heavy industries and especially in aerospace engineering. The mechanical properties of aluminum alloys are defined by a number of principal microstructural features. Conventional mathematical models of these properties are sometimes very complex to be analytically calculated. In this paper, a neural network model is used to predict the correlations between the hardness of aluminum alloys in relation to certain alloying elements. A backpropagation neural network is trained using a thorough dataset. The impact of certain elements is documented and an optimum structure is proposed.

  20. Development of Radiation Hard Radiation Detectors, Differences between Czochralski Silicon and Float Zone Silicon

    CERN Document Server

    Tuominen, Eija

    2012-01-01

    The purpose of this work was to develop radiation hard silicon detectors. Radiation detectors made ofsilicon are cost effective and have excellent position resolution. Therefore, they are widely used fortrack finding and particle analysis in large high-energy physics experiments. Silicon detectors willalso be used in the CMS (Compact Muon Solenoid) experiment that is being built at the LHC (LargeHadron Collider) accelerator at CERN (European Organisation for Nuclear Research). This work wasdone in the CMS programme of Helsinki Institute of Physics (HIP).Exposure of the silicon material to particle radiation causes irreversible defects that deteriorate theperformance of the silicon detectors. In HIP CMS Programme, our approach was to improve theradiation hardness of the silicon material with increased oxygen concentration in silicon material. Westudied two different methods: diffusion oxygenation of Float Zone silicon and use of high resistivityCzochralski silicon.We processed, characterised, tested in a parti...

  1. Radiation hard silicon sensors for the CMS tracker upgrade

    CERN Document Server

    Pohlsen, Thomas

    2013-01-01

    At an instantaneous luminosity of $5 \\times 10^{34}$ cm$^{-2}$ s$^{-1}$, the high-luminosity phase of the Large Hadron Collider (HL-LHC) is expected to deliver a total of $3\\,000$ fb$^{-1}$ of collisions, hereby increasing the discovery potential of the LHC experiments significantly. However, the radiation dose of the tracking systems will be severe, requiring new radiation hard sensors for the CMS tracker. The CMS tracker collaboration has initiated a large material investigation and irradiation campaign to identify the silicon material and design that fulfils all requirements for detectors for the HL-LHC. Focussing on the upgrade of the outer tracker region, pad sensors as well as fully functional strip sensors have been implemented on silicon wafers with different material properties and thicknesses. The samples were irradiated with a mixture of neutrons and protons corresponding to fluences as expected for the positions of detector layers in the future tracker. Different proton energies were used for irr...

  2. Development of high temperature, radiation hard detectors based on diamond

    Energy Technology Data Exchange (ETDEWEB)

    Metcalfe, Alex, E-mail: Alex.Metcalfe@brunel.ac.uk [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Fern, George R. [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Hobson, Peter R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Ireland, Terry; Salimian, Ali; Silver, Jack [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Smith, David R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Lefeuvre, Gwenaelle [Micron Semiconductor Ltd., Lancing BN15 8 SJ (United Kingdom); Saenger, Richard [Schlumberger Limited, 91240 Clamart (France)

    2017-02-11

    Single crystal CVD diamond has many desirable properties compared to current, well developed, detector materials; exceptional radiation, chemical and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry), wide bandgap and an intrinsic pathway to fast neutron detection through the {sup 12}C(n,α){sup 9}Be reaction. However effective exploitation of these properties requires development of a suitable metallisation scheme to give stable contacts for high temperature applications. To best utilise available processing techniques to optimise sensor response through geometry and conversion media configurations, a reliable model is required. This must assess the performance in terms of spectral response and overall efficiency as a function of detector and converter geometry. The same is also required for proper interpretation of experimental data. Sensors have been fabricated with varying metallisation schemes indented to permit high temperature operation; Present test results indicate that viable fabrication schemes for high temperature contacts have been developed and present modelling results, supported by preliminary data from partners indicate simulations provide a useful representation of response. - Highlights: • Radiation sensors using diamond as the sensitive volume have been constructed. • Functionality of these sensors with minimal degradation has been confirmed at 100 °C. • Sensitisation to thermal neutrons by addition of conversion layers has been modelled. • Modelling suggests 4× efficiency improvements from 3d converter-substrate interfaces.

  3. Test of radiation hardness of pcCVD detectors

    Energy Technology Data Exchange (ETDEWEB)

    Schlemme, Steffen [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Technische Universitaet Darmstadt (Germany); Enders, Joachim [Technische Universitaet Darmstadt (Germany); Figuera, P.; Salamone, S. [LNS-INFN Catania (Italy); Fruehauf, J.; Kis, Mladen; Kratz, A.; Kurz, N.; Loechner, S.; Nociforo, Chiara; Schirru, Fabio; Szczepanczyk, B.; Traeger, M.; Visinka, R. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Musumarra, A. [LNS-INFN Catania (Italy); University of Catania (Italy)

    2016-07-01

    The new in-flight separator Super-FRS is under construction at the Facility for Antiproton and Ion Research (FAIR, Darmstadt). Ion rates up to 3 x 10{sup 11} {sup 238}U/spill demand an adaption of detectors to a high radiation environment. A test experiment to investigate the radiation hardness of polycrystalline diamond detectors (pcCVD) was performed at the LNS-INFN in Catania using a {sup 12}C beam at 62 MeV/u and intensities of up to 1.5 pnA. The setup consisted of pcCVD strip detectors to measure the beam profile, a single crystal diamond detector to calibrate the ionisation chamber working in current mode as a beam intensity monitor and a pcCVD sample to be irradiated. The IC used was designed for FAIR and showed a stable counting rate allowing us to calibrate and perform beam intensity measurements with it. The total measured counts on the sample were 8.25 x 10{sup 11} counts/mm{sup 2} over a period of 60 hours. Digital waveforms of the pcCVD signals were taken with an oscilloscope and analysed. The results showed no change of the pcCVD signal properties during the entire irradiation.

  4. Radiation-hard semiconductor detectors for SuperLHC

    CERN Document Server

    Bruzzi, Mara; Al-Ajili, A A; Alexandrov, P; Alfieri, G; Allport, Philip P; Andreazza, A; Artuso, M; Assouak, S; Avset, B S; Barabash, L; Baranova, E; Barcz, A; Basile, A; Bates, R; Belova, N; Betta, G F D; Biagi, S F; Bilei, G M; Bisello, D; Blue, A; Blumenau, A; Boisvert, V; Bölla, G; Bondarenko, G B; Borchi, E; Borrello, L; Bortoletto, D; Boscardin, M; Bosisio, L; Bowcock, T J V; Brodbeck, T J; Broz, J; Brukhanov, A; Brzozowski, A; Buda, M; Buhmann, P; Buttar, C; Campabadal, F; Campbell, D; Candelori, A; Casse, G; Cavallini, A; Chilingarov, A G; Chren, D; Cindro, V; Citterio, M; Collins, P; Coluccia, R; Contarato, D; Coutinho, J; Creanza, D; Cunningham, W; Cvetkov, V; Davies, G; Dawson, I; De Palma, M; Demina, R; Dervan, P; Dierlamm, A; Dittongo, S; Dobrzanski, L; Dolezal, Z; Dolgolenko, A; Eberlein, T; Eremin, V; Fall, C; Fasolo, F; Ferbel, T; Fizzotti, F; Fleta, C; Focardi, E; Forton, E; Franchenko, S; Fretwurst, E; Gamaz, F; García-Navarro, J E; García, C; Gaubas, E; Genest, M H; Gill, K A; Giolo, K; Glaser, M; Gössling, C; Golovine, V; Gorelov, I; Goss, J; Gouldwell, A; Grégoire, G; Gregori, P; Grigoriev, E; Grigson, C; Grillo, A; Groza, A; Guskov, J; Haddad, L; Harding, R; Härkönen, J; Hauler, F; Hayama, S; Hoeferkamp, M; Honniger, F; Horazdovsky, T; Horisberger, R P; Horn, M; Houdayer, A; Hourahine, B; Hruban, A; Hughes, G; Ilyashenko, Yu S; Irmscher, K; Ivanov, A; Jarasiunas, K; Jin, T; Jones, B K; Jones, R; Joram, C; Jungermann, L; Kalinina, E; Kaminski, P; Karpenko, A; Karpov, A; Kazlauskiene, V; Kazukauskas, V; Khivrich, V; Khomenkov, V P; Kierstead, J A; Klaiber Lodewigs, J M; Kleverman, M; Klingenberg, R; Kodys, P; Kohout, Z; Korjenevski, S; Kowalik, A; Kozlowski, R; Kozodaev, M; Kramberger, G; Krasel, O; Kuznetsov, A; Kwan, S; Lagomarsino, S; Lari, T; Lassila-Perini, K M; Lastovetsky, V F; Latino, G; Latushkin, S T; Lazanu, I; Lazanu, S; Lebel, C; Leinonen, K; Leroy, C; Li, Z; Lindström, G; Lindström, L; Linhart, V; Litovchenko, A P; Litovchenko, P G; Litvinov, V; Lo Giudice, A; Lozano, M; Luczynski, Z; Luukka, Panja; Macchiolo, A; Mainwood, A; Makarenko, L F; Mandic, I; Manfredotti, C; Martí i García, S; Marunko, S; Mathieson, K; Melone, J; Menichelli, D; Meroni, C; Messineo, A; Miglio, S; Mikuz, M; Miyamoto, J; Moll, M; Monakhov, E; Moscatelli, F; Mozzanti, A; Murin, L; Naoumov, D; Nava, F; Nossarzhevska, E; Nummela, S; Nysten, J; Olivero, P; O'Shea, V; Palviainen, T; Paolini, C; Parkes, C; Passeri, D; Pein, U; Pellegrini, G; Perera, L; Petasecca, M; Piatkowski, B; Piemonte, C; Pignatel, G U; Pinho, N; Pintilie, I; Pintilie, L; Polivtsev, L; Polozov, P; Popa, A I; Popule, J; Pospísil, S; Pucker, G; Radicci, V; Rafí, J M; Ragusa, F; Rahman, M; Rando, R; Röder, R; Rohe, T; Ronchin, S; Rott, C; Roy, A; Roy, P; Ruzin, A; Ryazanov, A; Sadrozinski, H F W; Sakalauskas, S; Scaringella, M; Schiavulli, L; Schnetzer, S; Schumm, B; Sciortino, S; Scorzoni, A; Segneri, G; Seidel, S; Seiden, A; Sellberg, G; Sellin, P J; Sentenac, D; Sevilla, S G; Shipsey, I; Sícho, P; Sloan, T; Solar, M; Son, S; Sopko, B; Spencer, N; Stahl, J; Stavitski, I; Stolze, D; Stone, R; Storasta, J; Strokan, N; Strupinski, W; Sudzius, M; Surma, B; Suuronen, J; Suvorov, A; Svensson, B G; Tipton, P; Tomasek, M; Troncon, C; Tsvetkov, A; Tuominen, E; Tuovinen, E; Tuuva, T; Tylchin, M; Uebersee, H; Uher, J; Ullán, M; Vaitkus, J V; Vanni, P; Velthuis, J; Verbitskaya, E; Verzellesi, G; Vrba, V; Wagner, G; Wilhelm, I; Worm, S; Wright, V; Wunstorf, R; Zabierowski, P; Zaluzhny, A; Zavrtanik, M; Zen, M; Zhukov, V; Zorzi, N; de Boer, Wim

    2005-01-01

    An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 10/sup 35/ cm-/sup 2/s-/sup 1/ has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the interaction region will receive severe doses of fast hadron irradiation and the inner tracker detectors will need to survive fast hadron fluences of up to above 10 /sup 16/ cm-/sup 2/. The CERN-RD50 project "Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders" has been established in 2002 to explore detector materials and technologies that will allow to operate devices up to, or beyond, this limit. The strategies followed by RD50 to enhance the radiation tolerance include the development of new or defect engineered detector materials (SiC, GaN, Czochralski and epitaxial silicon, oxygen enriched Flo...

  5. Shutdown and degradation: Space computers for nuclear application, verification of radiation hardness. Final report

    International Nuclear Information System (INIS)

    Eichhorn, E.; Gerber, V.; Schreyer, P.

    1995-01-01

    (1) Employment of those radiation hard electronics which are already known in military and space applications. (2) The experience in space-flight shall be used to investigate nuclear technology areas, for example, by using space electronics to prove the range of applications in nuclear radiating environments. (3) Reproduction of a computer developed for telecommunication satellites; proof of radiation hardness by radiation tests. (4) At 328 Krad (Si) first failure of radiation tolerant devices with 100 Krad (Si) hardness guaranteed. (5) Using radiation hard devices of the same type you can expect applications at doses of greater than 1 Mrad (Si). Electronic systems applicable for radiation categories D, C and lower part of B for manipulators, vehicles, underwater robotics. (orig.) [de

  6. Study of fast electrons from hard-X radiation

    International Nuclear Information System (INIS)

    Arslanbekov, R.

    1995-01-01

    The goal of this thesis is the study of fast electron dynamics by means of the hard X-ray diagnosis installed in TORE SUPRA and numerical simulations. Fast electrons are generated in the plasma in the presence of the injected lower hybrid (LH) waves. Two aspects are studied in detail: the lower hybrid wave propagation and absorption in a periodically perturbed media and 2-D Fokker-Planck modelling of the fast electron dynamics in the presence of the LH power. Ripple effects on lower hybrid wave propagation and absorption are investigated using the ray tracing technique. A cylindrical equilibrium is first studied and a strong modification of the ray dynamics is predicted. Calculations are carried out in a real toroidal geometry corresponding to TORE SUPRA. It is shown that the lack of toroidal axisymmetry of the magnetic field may result in a modification of the ray evolution even if the global ray evolution is governed by the larger poloidal inhomogeneity. Simulation of LH experiments are performed for TORE SUPRA tokamak which has a large magnetic ripple (7% at the plasma edge). By considering ripple perturbation in LH current drive simulations, a better agreement is found with experimental results, in particular with the hard-X spectra and the current density profiles. In the second part of the thesis, a 2-D modeling of the fast electron dynamics in the velocity phase space is considered, based on the 2-D relativistic electron Fokker-Planck equation. Electron distribution functions obtained are used to calculate non-thermal Bremsstrahlung emission for different TORE SUPRA shots in a wide range of experimental conditions. (J.S.). 168 refs., 93 figs., 1 tab., 3 appendix

  7. Radiation-hard/high-speed parallel optical links

    International Nuclear Information System (INIS)

    Gan, K.K.; Buchholz, P.; Kagan, H.P.; Kass, R.D.; Moore, J.; Smith, D.S.; Wiese, A.; Ziolkowski, M.

    2014-01-01

    We have designed an ASIC for use in a parallel optical engine for a new layer of the ATLAS pixel detector in the initial phase of the LHC luminosity upgrade. The ASIC is a 12-channel VCSEL (Vertical Cavity Surface Emitting Laser) array driver capable of operating up to 5 Gb/s per channel. The ASIC is designed using a 130 nm CMOS process to enhance the radiation-hardness. A scheme for redundancy has also been implemented to allow bypassing of a broken VCSEL. The ASIC also contains a power-on reset circuit that sets the ASIC to a default configuration with no signal steering. In addition, the bias and modulation currents of the individual channels are programmable. The performance of the first prototype ASIC up to 5 Gb/s is satisfactory. Furthermore, we are able to program the bias and modulation currents and to bypass a broken VCSEL channel. We are currently upgrading our design to allow operation at 10 Gb/s per channel yielding an aggregated bandwidth of 120 Gb/s. Some preliminary results of the design will be presented

  8. Chronic radiation effects on dental hard tissue (''radiation carries''). Classification and therapeutic strategies

    International Nuclear Information System (INIS)

    Groetz, K.A.; Brahm, R.; Al-Nawas, B.; Wagner, W.; Riesenbeck, D.; Willich, N.; Seegenschmiedt, M.H.

    2001-01-01

    Objectives: Since the first description of rapid destruction of dental hard tissues following head and neck radiotherapy 80 years ago, 'radiation caries' is an established clinical finding. The internationally accepted clinical evaluation score RTOG/EORTC however is lacking a classification of this frequent radiogenic alteration. Material and Methods: Medical records, data and images of radiation effects on the teeth of more than 1,500 patients, who underwent periradiotherapeutic care, were analyzed. Macroscopic alterations regarding the grade of late lesions of tooth crowns were used for a classification into 4 grades according to the RTOG/EORTC guidelines. Results: No early radiation effects were found by macroscopic inspection. In the first 90 days following radiotherapy 1/3 of the patients complained of reversible hypersensitivity, which may be related to a temporary hyperemia of the pulp. It was possible to classify radiation caries as a late radiation effect on a graded scale as known from RTOG/EORTC for other organ systems. This is a prerequisite for the integration of radiation caries into the international nomenclature of the RTOG/EORTC classification. Conclusions: The documentation of early radiation effects on dental hard tissues seems to be neglectable. On the other hand the documentation of late radiation effects has a high clinical impact. The identification of an initial lesion at the high-risk areas of the neck and incisal part of the tooth can lead to a successful therapy as a major prerequisite for orofacial rehabilitation. An internationally standardized documentation is a basis for the evaluation of the side effects of radiooncotic therapy as well as the effectiveness of protective and supportive procedures. (orig.) [de

  9. Selecting Optimal Random Forest Predictive Models: A Case Study on Predicting the Spatial Distribution of Seabed Hardness

    Science.gov (United States)

    Li, Jin; Tran, Maggie; Siwabessy, Justy

    2016-01-01

    Spatially continuous predictions of seabed hardness are important baseline environmental information for sustainable management of Australia’s marine jurisdiction. Seabed hardness is often inferred from multibeam backscatter data with unknown accuracy and can be inferred from underwater video footage at limited locations. In this study, we classified the seabed into four classes based on two new seabed hardness classification schemes (i.e., hard90 and hard70). We developed optimal predictive models to predict seabed hardness using random forest (RF) based on the point data of hardness classes and spatially continuous multibeam data. Five feature selection (FS) methods that are variable importance (VI), averaged variable importance (AVI), knowledge informed AVI (KIAVI), Boruta and regularized RF (RRF) were tested based on predictive accuracy. Effects of highly correlated, important and unimportant predictors on the accuracy of RF predictive models were examined. Finally, spatial predictions generated using the most accurate models were visually examined and analysed. This study confirmed that: 1) hard90 and hard70 are effective seabed hardness classification schemes; 2) seabed hardness of four classes can be predicted with a high degree of accuracy; 3) the typical approach used to pre-select predictive variables by excluding highly correlated variables needs to be re-examined; 4) the identification of the important and unimportant predictors provides useful guidelines for further improving predictive models; 5) FS methods select the most accurate predictive model(s) instead of the most parsimonious ones, and AVI and Boruta are recommended for future studies; and 6) RF is an effective modelling method with high predictive accuracy for multi-level categorical data and can be applied to ‘small p and large n’ problems in environmental sciences. Additionally, automated computational programs for AVI need to be developed to increase its computational efficiency and

  10. Comptonization of low-frequency radiation in accretion disks Angular distribution and polarization of hard X-ray radiation

    International Nuclear Information System (INIS)

    Suniaev, R.A.; Titarchuk, L.G.

    1984-01-01

    Analytical consideration is given to the comptonization of photons and its effects on the radiation emitted from accretion disks of compact X-ray sources, such as black holes and neutron stars. Attention is given to the photon distribution during escape from the disk, the angular distribution of hard radiation from the disk, the polarization of hard radiation and the electron temperature distribution over the optical depth. It is shown that the hard radiation spectrum is independent of the low-frequency photon source distribution. The angular distribution and polarization of the outgoing X-rays are a function of the optical depth. A Thomson approximation is used to estimate the angular distribution of the hard radiation and the polarization over the disk. The polarization results are compared with OSO-8 satellite data for Cyg X-1 and show good agreement at several energy levels. 17 references

  11. Effect of gamma radiation on micromechanical hardness of lead-free solder joint

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, Wilfred [Universiti Kebangsaan Malaysia, Bangi, 43600 Kajang, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahman, Irman Abdul; Jalar, Azman; Kamil, Insan; Bakar, Maria Abu [Universiti Kebangsaan Malaysia, Bangi, 43600 Kajang, Selangor (Malaysia); Yusoff, Wan Yusmawati Wan [Universiti Pertahanan Nasional Malaysia, Kem Sg. Besi, 57000 Kuala Lumpur (Malaysia)

    2015-09-25

    Lead-free solders are important material in nano and microelectronic surface mounting technology for various applications in bio medicine, environmental monitoring, spacecraft and satellite instrumentation. Nevertheless solder joint in radiation environment needs higher reliability and resistance to any damage caused by ionizing radiations. In this study a lead-free 99.0Sn0.3Ag0.7Cu wt.% (SAC) solder joint was developed and subjected to various doses of gamma radiation to investigate the effects of the ionizing radiation to micromechanical hardness of the solder. Averaged hardness of the SAC joint was obtained from nanoindentation test. The results show a relationship between hardness values of indentations and the increment of radiation dose. Highest mean hardness, 0.2290 ± 0.0270 GPa was calculated on solder joint which was exposed to 5 Gray dose of gamma radiation. This value indicates possible radiation hardening effect on irradiated solder. The hardness gradually decreased to 0.1933 ± 0.0210 GPa and 0.1631 ± 0.0173 GPa when exposed to doses 50 and 500 gray respectively. These values are also lower than the hardness of non irradiated sample which was calculated as 0.2084 ± 0.0.3633 GPa indicating possible radiation damage and needs further related atomic dislocation study.

  12. Towards Radiation Hard Sensor Materials for the CMS Tracker Upgrade

    CERN Document Server

    Steinbrueck, Georg

    2012-01-01

    Many measurements are described in literature, performed on a variety of silicon materials and technologies, but they are often hard to compare, because they were done under different conditions. To systematically compare the prope...

  13. Effects of device scaling and geometry on MOS radiation hardness assurance

    International Nuclear Information System (INIS)

    Shaneyfelt, M.R.; Fleetwood, D.M.; Winokur, P.S.; Schwank, J.R.; Meisenheimer, T.L.

    1993-01-01

    In this work the authors investigate the effects of transistor scaling and geometry on radiation hardness. The total dose response is shown to depend strongly on transistor channel length. Specifically, transistors with shorter gate lengths tend to show more negative threshold-voltage shifts during irradiation than transistors with longer gate lengths. Similarly, transistors with longer gate lengths tend to show more positive threshold-voltage shifts during post-irradiation annealing than transistors with shorter gate lengths. These differences in radiation response, caused by differences in transistor size and geometry, will be important to factor into test-structure-to-IC correlations necessary to support cost-effective Qualified Manufacturers List (QML) hardness assurance. Transistors with minimum gate length (more negative ΔV th ) will have a larger effect on standby power supply current for an IC at high dose rates, such as in a weapon environment, where worst-case response is associated with negative threshold-voltage shifts during irradiation. On the other hand, transistors with maximum gate length (more positive ΔV th ) will have a larger effect on the timing parameters of an IC at low dose rates, such as in a space environment, where worst-case response is represented by positive threshold-voltage shifts after postirradiation anneal. The channel size and geometry effects they observe cannot be predicted from simple scaling models, but occur because of real differences in oxide-, interface-, and border-trap charge densities among devices of different sizes

  14. Uncooled Radiation Hard SiC Schottky VUV Detectors Capable of Single Photon Sensing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to design, fabricate, characterize and commercialize very large area, uncooled and radiative hard 4H-SiC VUV detectors capable of near single...

  15. Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

    CERN Document Server

    Adzic, P.; Andelin, D.; Anicin, I.; Antunovic, Z.; Arcidiacono, R.; Arenton, M.W.; Auffray, E.; Argiro, S.; Askew, A.; Baccaro, S.; Baffioni, S.; Balazs, M.; Bandurin, D.; Barney, D.; Barone, L.M.; Bartoloni, A.; Baty, C.; Beauceron, S.; Bell, K.W.; Bernet, C.; Besancon, M.; Betev, B.; Beuselinck, R.; Biino, C.; Blaha, J.; Bloch, P.; Borisevitch, A.; Bornheim, A.; Bourotte, J.; Brown, R.M.; Buehler, M.; Busson, P.; Camanzi, B.; Camporesi, T.; Cartiglia, N.; Cavallari, F.; Cecilia, A.; Chang, P.; Chang, Y.H.; Charlot, C.; Chen, E.A.; Chen, W.T.; Chen, Z.; Chipaux, R.; Choudhary, B.C.; Choudhury, R.K.; Cockerill, D.J.A.; Conetti, S.; Cooper, S.I.; Cossutti, F.; Cox, B.; Cussans, D.G.; Dafinei, I.; Da Silva Di Calafiori, D.R.; Daskalakis, G.; David, A.; Deiters, K.; Dejardin, M.; De Benedetti, A.; Della Ricca, G.; Del Re, D.; Denegri, D.; Depasse, P.; Descamps, J.; Diemoz, M.; Di Marco, E.; Dissertori, G.; Dittmar, M.; Djambazov, L.; Djordjevic, M.; Dobrzynski, L.; Dolgopolov, A.; Drndarevic, S.; Drobychev, G.; Dutta, D.; Dzelalija, M.; Elliott-Peisert, A.; El Mamouni, H.; Evangelou, I.; Fabbro, B.; Faure, J.L.; Fay, J.; Fedorov, A.; Ferri, F.; Franci, D.; Franzoni, G.; Freudenreich, K.; Funk, W.; Ganjour, S.; Gascon, S.; Gataullin, M.; Gentit, F.X.; Ghezzi, A.; Givernaud, A.; Gninenko, S.; Go, A.; Gobbo, B.; Godinovic, N.; Golubev, N.; Govoni, P.; Grant, N.; Gras, P.; Haguenauer, M.; Hamel de Monchenault, G.; Hansen, M.; Haupt, J.; Heath, H.F.; Heltsley, B.; Cornell U., LNS.; Hintz, W.; Hirosky, R.; Hobson, P.R.; Honma, A.; Hou, G.W.S.; Hsiung, Y.; Huhtinen, M.; Ille, B.; Ingram, Q.; Inyakin, A.; Jarry, P.; Jessop, C.; Jovanovic, D.; Kaadze, K.; Kachanov, V.; Kailas, S.; Kataria, S.K.; Kennedy, B.W.; Kokkas, P.; Kolberg, T.; Korjik, M.; Krasnikov, N.; Krpic, D.; Kubota, Y.; Kuo, C.M.; Kyberd, P.; Kyriakis, A.; Lebeau, M.; Lecomte, P.; Lecoq, P.; Ledovskoy, A.; Lethuillier, M.; Lin, S.W.; Lin, W.; Litvine, V.; Locci, E.; Longo, E.; Loukas, D.; Luckey, P.D.; Lustermann, W.; Ma, Y.; Malberti, M.; Malcles, J.; Maletic, D.; Manthos, N.; Maravin, Y.; Marchica, C.; Marinelli, N.; Markou, A.; Markou, C.; Marone, M.; Matveev, V.; Mavrommatis, C.; Meridiani, P.; Milenovic, P.; Mine, P.; Missevitch, O.; Mohanty, A.K.; Moortgat, F.; Musella, P.; Musienko, Y.; Nardulli, A.; Nash, J.; Nedelec, P.; Negri, P.; Newman, H.B.; Nikitenko, A.; Nessi-Tedaldi, F.; Obertino, M.M.; Organtini, G.; Orimoto, T.; Paganoni, M.; Paganini, P.; Palma, A.; Pant, L.; Papadakis, A.; Papadakis, I.; Papadopoulos, I.; Paramatti, R.; Parracho, P.; Pastrone, N.; Patterson, J.R.; Pauss, F.; Peigneux, J.P.; Petrakou, E.; Phillips, D.G.; Piroue, P.; Ptochos, F.; Puljak, I.; Pullia, A.; Punz, T.; Puzovic, J.; Ragazzi, S.; Rahatlou, S.; Rander, J.; Razis, P.A.; Redaelli, N.; Renker, D.; Reucroft, S.; Ribeiro, P.; Rogan, C.; Ronquest, M.; Rosowsky, A.; Rovelli, C.; Rumerio, P.; Rusack, R.; Rusakov, S.V.; Ryan, M.J.; Sala, L.; Salerno, R.; Schneegans, M.; Seez, C.; Sharp, P.; Shepherd-Themistocleous, C.H.; Shiu, J.G.; Shivpuri, R.K.; Shukla, P.; Siamitros, C.; Sillou, D.; Silva, J.; Silva, P.; Singovsky, A.; Sirois, Y.; Sirunyan, A.; Smith, V.J.; Stockli, F.; Swain, J.; Tabarelli de Fatis, T.; Takahashi, M.; Tancini, V.; Teller, O.; Theofilatos, K.; Thiebaux, C.; Timciuc, V.; Timlin, C.; Titov, Maxim P.; Topkar, A.; Triantis, F.A.; Troshin, S.; Tyurin, N.; Ueno, K.; Uzunian, A.; Varela, J.; Verrecchia, P.; Veverka, J.; Virdee, T.; Wang, M.; Wardrope, D.; Weber, M.; Weng, J.; Williams, J.H.; Yang, Y.; Yaselli, I.; Yohay, R.; Zabi, A.; Zelepoukine, S.; Zhang, J.; Zhang, L.Y.; Zhu, K.; Zhu, R.Y.

    2010-01-01

    Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.

  16. Development of radiation hard components for ITER blanket remote handling system

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Makiko, E-mail: saito.makiko@jaea.go.jp; Anzai, Katsunori; Maruyama, Takahito; Noguchi, Yuto; Ueno, Kenichi; Takeda, Nobukazu; Kakudate, Satoshi

    2016-11-01

    Highlights: • Clarify the components that will degrade by gamma ray irradiation. • Perform the irradiation tests to BRHS components. • Optimize the materials to increase the radiation hardness. - Abstract: The ITER blanket remote handling system (BRHS) will be operated in a high radiation environment (250 Gy/h max.) and must stably handle the blanket modules, which weigh 4.5 t and are more than 1.5 m in length, with a high degree of position and posture accuracy. The reliability of the system can be improved by reviewing the failure events of the system caused by high radiation. A failure mode and effects analysis (FMEA) identified failure modes and determined that lubricants, O-rings, and electric insulation cables were the dominant components affecting radiation hardness. Accordingly, we tried to optimize the lubricants and cables of the AC servo motors by using polyphenyl ether (PPE)-based grease and polyether ether ketone (PEEK), respectively. Materials containing radiation protective agents were also selected for the cable sheaths and O-rings to improve radiation hardness. Gamma ray irradiation tests were performed on these components and as a result, a radiation hardness of 8 MGy was achieved for the AC servo motors. On the other hand, to develop the radiation hardness and BRHS compatibility furthermore, the improvement of materials of cable and O ring were performed.

  17. Radiation-hard silicon photonics for high energy physics and beyond

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Silicon photonics (SiPh) is currently being investigated as a promising technology for future radiation hard optical links. The possibility of integrating SiPh devices with electronics and/or silicon particle sensors as well as an expected very high resistance against radiation damage make this technology particularly interesting for potential use close to the interaction points in future in high energy physics experiments and other radiation-sensitive applications. The presentation will summarize the outcomes of the research on radiation hard SiPh conducted within the ICE-DIP projected.

  18. Study of hard braking x-ray radiation on the radiation-beam complex ''TEMP''

    International Nuclear Information System (INIS)

    Batrakov, A.B.; Glushko, E.G.; Egorov, A.M.; Zinchenko, A.A.; Litvinenko, V.V.; Lonin, Yu.F.; Ponomarev, A.G.; Rybka, A.V.; Fedotov, S.I.; Uvarov, V.T.

    2015-01-01

    A calculation over of basic parameters of the hard brake x-rayed radiation for the microsecond accelerating of relativistic electronic beam T EMP . Optimization of converters is conducted for these aims. Maximal doses are experimentally got brake x-rayed radiation on beam-radiation complex T EMP . The diagrams of orientation of the brake x-rayed radiation are taken off depending on energies of bunches and forms of electrodes.

  19. Hardness measurements of silicon rubber and polyurethane rubber cured by ionizing radiation

    International Nuclear Information System (INIS)

    Basfar, A.A.

    1995-01-01

    This work investigates the hardness of both silicon rubber and polyurethane rubber cured by ionizing radiation. Shore A Hardness is used to characterize the subject elastomers in relation to the crosslinking process. Various formulations of both materials have been investigated in order to achieve the optimum cure conditions desired. A small amount of the curing agent has been incorporated in some formulations in order to reduce the required dose to achieve full cure conditions. Silicon rubber has shown improvements in hardness as absorbed dose is increased, whereas hardness remained constant over a range of absorbed doses for polyurethane rubber

  20. Radiation Hard and High Light Yield Scintillator Search for CMS Phase II Upgrade

    CERN Document Server

    Tiras, Emrah

    2015-01-01

    The CMS detector at the LHC requires a major upgrade to cope with the higher instantaneous luminosity and the elevated radiation levels. The active media of the forward backing hadron calorimeters is projected to be radiation-hard, high light yield scintillation materials or similar alternatives. In this context, we have studied various radiation-hard scintillating materials such as Polyethylene Terephthalate (PET), Polyethylene Naphthalate (PEN), High Efficiency Mirror (HEM) and quartz plates with various coatings. The quartz plates are pure Cerenkov radiators and their radiation hardness has been confirmed. In order to increase the light output, we considered organic and inorganic coating materials such as p-Terphenyl (pTp), Anthracene and Gallium-doped Zinc Oxide (ZnO Ga) that are applied as thin layers on the surface of the quartz plates. Here, we present the results of the related test beam activities, laboratory measurements and recent developments.

  1. Integration of Radiation-Hard Magnetic Random Access Memory with CMOS ICs

    CERN Document Server

    Cerjan, C J

    2000-01-01

    The research undertaken in this LDRD-funded project addressed the joint development of magnetic material-based nonvolatile, radiation-hard memory cells with Sandia National Laboratory. Specifically, the goal of this project was to demonstrate the intrinsic radiation-hardness of Giant Magneto-Resistive (GMR) materials by depositing representative alloy combinations upon radiation-hardened silicon-based integrated circuits. All of the stated goals of the project were achieved successfully. The necessary films were successfully deposited upon typical integrated circuits; the materials retained their magnetic field response at the highest radiation doses; and a patterning approach was developed that did not degrade the as-fabricated properties of the underlying circuitry. These results establish the feasibility of building radiation-hard magnetic memory cells.

  2. Prediction of hardness for Al-Cu-Zn alloys in as-cast and quenching conditions

    International Nuclear Information System (INIS)

    Villegas-Cardenas, J. D.; Saucedo-Munoz, M. L.; Lopez-Hirata, V. M.; Dorantes Rosales, H. J.

    2014-01-01

    This work presents a new experimental and numerical methodology in order to predict the hardness in the as-cast, and solution treated and quenched Al-Cu-Zn alloys. Chemical composition of alloys is located inside two straight lines represented by two equations. Eight different compositions were selected from each line. All the alloys were characterized for light microscope, scanning electron microscope, X-ray diffraction and Rockwell B hardness test. The equilibrium phases were obtained at different temperatures by Thermo-Calc. The microstructure characterization and regression analysis enabled to determine the phase transformations and two equations of hardness assessment. The combination of hardness equations and composition line equations permitted to estimate the hardness of any alloy composition inside this zone. This was verified by calculating hardness with the information reported in other works, with an error lower than 7% in the estimated hardness. (Author)

  3. Inclusion of Radiation Environment Variability in Total Dose Hardness Assurance Methodology

    Science.gov (United States)

    Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; LaBel, K. A.

    2016-01-01

    Variability of the space radiation environment is investigated with regard to parts categorization for total dose hardness assurance methods. It is shown that it can have a significant impact. A modified approach is developed that uses current environment models more consistently and replaces the radiation design margin concept with one of failure probability during a mission.

  4. CeF3(Ba) radiation hard scintillator for electromagnetic calorimeters

    International Nuclear Information System (INIS)

    Aseev, A.A.; Devitsin, E.G.; Kozlov, V.A.; Hovepyan, Yu.I.; Potashov, S.Yu.; Sokolovsky, K.A.; Uvarova, T.V.; Vasilchenko, V.G.

    1992-01-01

    The influence of divalent fluoride dopants BaF 2 , CaF 2 , SrF 2 on radiation and luminescent properties of CeF 3 crystal is studied. A high radiation hardness (>10 8 rad) has been obtained for CeF 3 crystals doped with BaF 2 . (orig.)

  5. Radiation-hard Silicon Photonics for Future High Energy Physics Experiments

    CERN Document Server

    AUTHOR|(CDS)2089774; Troska, Jan

    Collisions of proton beams in the Large Hadron Collider at CERN produce very high radiation levels in the innermost parts of the particle detectors and enormous amounts of measurement data. Thousands of radiation-hard optical links based on directly-modulated laser diodes are thus installed in the particle detectors to transmit the measurement data to the processing electronics. The radiation levels in the innermost regions of future particle detectors will be much higher than they are now. Alternative solutions to laser-based radiation-hard optical links have to be found since the performance of laser diodes decreases beyond the operation margin of the system when irradiated to sufficiently high radiation levels. Silicon Photonics (SiPh) is currently being investigated as a promising alternative technology. First tests have indeed shown that SiPh Mach-Zehnder modulators (MZMs) are relatively insensitive to a high neutron fluence. However, they showed a strong degradation when exposed to ionizing radiation. ...

  6. Radiation hardness on very front-end for SPD

    International Nuclear Information System (INIS)

    Cano, Xavier; Graciani, Ricardo; Gascon, David; Garrido, Lluis; Bota, Sebastia; Herms, Atila; Comerma, Albert; Riera, Jordi

    2005-01-01

    The calorimeter front-end electronics of the LHCb experiment will be located in a region, which is not protected from radiation. Therefore, all the electronics must be qualified to stand some defined radiation levels. The procedure, measurements and results of an irradiation test for every component of the very front-end SPD detector, which is part of the LHCb calorimeter are presented here. All the tested components, except a custom made ASIC, are commercially available

  7. Transition radiation in metal-metal multilayer nanostructures as a medical source of hard x-ray radiation

    International Nuclear Information System (INIS)

    Pokrovsky, A. L.; Kaplan, A. E.; Shkolnikov, P. L.

    2006-01-01

    We show that a periodic metal-metal multilayer nanostructure can serve as an efficient source of hard x-ray transition radiation. Our research effort is aimed at developing an x-ray source for medical applications, which is based on using low-energy relativistic electrons. The approach toward choosing radiator-spacer couples for the generation of hard x-ray resonant transition radiation by few-MeV electrons traversing solid multilayer structures for the energies of interest to medicine (30-50 keV) changes dramatically compared with that for soft x-ray radiation. We show that one of the main factors in achieving the required resonant line is the absence of the contrast of the refractive indices between the spacer and the radiator at the far wings of the radiation line; for that purpose, the optimal spacer, as a rule, should have a higher atomic number than the radiator. Having experimental goals in mind, we have considered also the unwanted effects due to bremsstrahlung radiation, absorption and scattering of radiated photons, detector-related issues, and inhibited coherence of transition radiation due to random deviation of spacing between the layers. Choosing as a model example a Mo-Ag radiator-spacer pair of materials, we demonstrate that the x-ray transition radiation line can be well resolved with the use of spatial and frequency filtering

  8. Radiation-hard Optoelectronics for LHC detector upgrades.

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00375195; Newbold, Dave

    A series of upgrades foreseen for the LHC over the next decade will allow the proton-proton collisions to reach the design center of mass energy of 14 TeV and increase the luminosity to five times (High Luminosity-LHC) the design luminosity by 2027. Radiation-tolerant high-speed optical data transmission links will continue to play an important role in the infrastructure of particle physics experiments over the next decade. A new generation of optoelectronics that meet the increased performance and radiation tolerance limits imposed by the increase in the intensity of the collisions at the interaction points are currently being developed. This thesis focuses on the development of a general purpose bi-directional 5 Gb/s radiation tolerant optical transceiver, the Versatile Transceiver (VTRx), for use by the LHC experiments over the next five years, and on exploring the radiation-tolerance of state-of-the art silicon photonics modulators for HL-LHC data transmission applications. The compliance of the VTRx ...

  9. Building memristive and radiation hardness TiO{sub 2}-based junctions

    Energy Technology Data Exchange (ETDEWEB)

    Ghenzi, N., E-mail: n.ghenzi@gmail.com [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Rubi, D. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); ECyT, UNSAM, Martín de Irigoyen 3100, 1650 San Martín, Bs As (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Mangano, E.; Gimenez, G. [Instituto Nacional de Tecnología Industrial (INTI) (Argentina); Lell, J. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica (Argentina); Zelcer, A. [Gerencia Química, Comisión Nacional de Energía Atómica (Argentina); ECyT, UNSAM, Martín de Irigoyen 3100, 1650 San Martín, Bs As (Argentina); Stoliar, P. [ECyT, UNSAM, Martín de Irigoyen 3100, 1650 San Martín, Bs As (Argentina); IMN, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes (France); and others

    2014-01-01

    We study micro-scale TiO{sub 2} junctions that are suitable to be used as resistive random-access memory nonvolatile devices with radiation hardness memristive properties. The fabrication and structural and electrical characterization of the junctions are presented. We obtained a retentivity of 10{sup 5} s, an endurance of 10{sup 4} cycles and reliable switching with short electrical pulses (time-width below 10 ns). Additionally, the devices were exposed to 25 MeV oxygen ions. Then, we performed electrical measurements comparing pristine and irradiated devices in order to check the feasibility of using these junctions as memory elements with memristive and radiation hardness properties. - Highlights: • We fabricated radiation hardness memristive metal insulator metal junctions. • We characterized the structural properties of the devices. • We showed the feasibility of the junctions as a non-volatile memory.

  10. Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

    Science.gov (United States)

    Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

    2018-05-01

    Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

  11. Room Temperature Hard Radiation Detectors Based on Solid State Compound Semiconductors: An Overview

    Science.gov (United States)

    Mirzaei, Ali; Huh, Jeung-Soo; Kim, Sang Sub; Kim, Hyoun Woo

    2018-03-01

    Si and Ge single crystals are the most common semiconductor radiation detectors. However, they need to work at cryogenic temperatures to decrease their noise levels. In contrast, compound semiconductors can be operated at room temperature due to their ability to grow compound materials with tunable densities, band gaps and atomic numbers. Highly efficient room temperature hard radiation detectors can be utilized in biomedical diagnostics, nuclear safety and homeland security applications. In this review, we discuss room temperature compound semiconductors. Since the field of radiation detection is broad and a discussion of all compound materials for radiation sensing is impossible, we discuss the most important materials for the detection of hard radiation with a focus on binary heavy metal semiconductors and ternary and quaternary chalcogenide compounds.

  12. Hydrogenated amorphous silicon radiation detectors: Material parameters; radiation hardness; charge collection

    International Nuclear Information System (INIS)

    Qureshi, S.

    1991-01-01

    Properties of hydrogenated amorphous silicon p-i-n diodes relevant to radiation detection applications were studied. The interest in using this material for radiation detection applications in physics and medicine was motivated by its high radiation hardness and the fact that it can be deposited over large area at relatively low cost. Thick, fully depleted a-Si:H diodes are required for sufficient energy deposition by a charged particle and better signal to noise ratio. A sizeable electric field is essential for charge collection in a -Si:H diodes. The large density of ionized defects that exist in the i layer when the diode is under DC bias causes the electric field to be uniform. Material parameters, namely carrier mobility and lifetime and the ionized defect density in thick a-Si:H p-i-n diodes were studied by the transient photoconductivity method. The increase in diode leakage current with reverse bias over the operating bias was consistent with the Poole-Frenkel effect, involving excitation of carriers from neutral defects. The diode noise over the operating voltage range was completely explained in terms of the shot noise component for CR-(RC) 4 (pseudo-Gaussian) shaping at 3 μs shaping time and the noise component at 0 V bias (delta and thermal noise) added in quadrature. Irradiation with 1 Mev neutrons produced no significant degradation in leakage current and noise at fluences exceeding 4 x 10 14 cm -2 . Irradiation with 1.4 Mev proton fluence of 1 x 10 14 cm -2 decreased carrier lifetime by a factor of ∼4. Degradation in leakage current and noise became significant at proton fluence of ∼10 13 cm -2

  13. The effect of gamma radiation on hardness evolution in high density polyethylene at elevated temperatures

    International Nuclear Information System (INIS)

    Chen, Pei-Yun; Chen, C.C.; Harmon, Julie P.; Lee, Sanboh

    2014-01-01

    This research focuses on characterizing hardness evolution in irradiated high density polyethylene (HDPE) at elevated temperatures. Hardness increases with increasing gamma ray dose, annealing temperature and annealing time. The hardness change is attributed to the variation of defects in microstructure and molecular structure. The kinetics of defects that control the hardness are assumed to follow the first order structure relaxation. The experimental data are in good agreement with the predicted model. The rate constant follows the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The defects that control hardness in post-annealed HDPE increase with increasing dose and annealing temperature. The structure relaxation of HDPE has a lower energy of mixing in crystalline regions than in amorphous regions. Further, the energy of mixing for defects that influence hardness in HDPE is lower than those observed in polycarbonate (PC), poly(methyl methacrylate) (PMMA) and poly (hydroxyethyl methacrylate) (HEMA). This is due to the fact that polyethylene is a semi-crystalline material, while PC, PMMA and PHEMA are amorphous. - Highlights: • Hardness of HDPE increases with increasing gamma ray dose, annealing time and temperature. • The hardness change arises from defects in microstructure and molecular structure. • Defects affecting hardness follow a kinetics of structure relaxation. • The structure relaxation has a low energy of mixing in crystalline regime

  14. The effect of gamma radiation on hardness evolution in high density polyethylene at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pei-Yun [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chen, C.C. [Institute of Nuclear Energy Research, Longtan, Taoyuan 325, Taiwan (China); Harmon, Julie P. [Department of Chemistry, University of South Florida, Tampa, FL 33620 (United States); Lee, Sanboh, E-mail: sblee@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China)

    2014-08-01

    This research focuses on characterizing hardness evolution in irradiated high density polyethylene (HDPE) at elevated temperatures. Hardness increases with increasing gamma ray dose, annealing temperature and annealing time. The hardness change is attributed to the variation of defects in microstructure and molecular structure. The kinetics of defects that control the hardness are assumed to follow the first order structure relaxation. The experimental data are in good agreement with the predicted model. The rate constant follows the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The defects that control hardness in post-annealed HDPE increase with increasing dose and annealing temperature. The structure relaxation of HDPE has a lower energy of mixing in crystalline regions than in amorphous regions. Further, the energy of mixing for defects that influence hardness in HDPE is lower than those observed in polycarbonate (PC), poly(methyl methacrylate) (PMMA) and poly (hydroxyethyl methacrylate) (HEMA). This is due to the fact that polyethylene is a semi-crystalline material, while PC, PMMA and PHEMA are amorphous. - Highlights: • Hardness of HDPE increases with increasing gamma ray dose, annealing time and temperature. • The hardness change arises from defects in microstructure and molecular structure. • Defects affecting hardness follow a kinetics of structure relaxation. • The structure relaxation has a low energy of mixing in crystalline regime.

  15. GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

    Science.gov (United States)

    Son, Kyung-ah; Liao, Anna; Lung, Gerald; Gallegos, Manuel; Hatakeh, Toshiro; Harris, Richard D.; Scheick, Leif Z.; Smythe, William D.

    2010-01-01

    We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....

  16. Radiation Hardness Study of CsI(Tl) Crystals for Belle II Calorimeter

    CERN Document Server

    Matvienko, D V; Sedov, E V; Shwartz, B A

    2017-01-01

    The Belle II calorimeter (at least, its barrel part) consists of CsI(Tl) scintillation crystals which have been used at the Belle experiment. We perform the radiation hardness study of some typical Belle crystals and conclude their light output reductions are acceptable for Belle II experiment where the absorption dose can reach 10 krad during the detector operation. CsI(Tl) crystals have high stablity and low maintenance cost and are considered as possible option for the calorimeter of the future Super-Charm-Tau factory (SCT) in Novosibirsk. Our study demonstrates sufficiently high radiation hardness of CsI(Tl) crystals for SCT conditions.

  17. Radiation hardness of LuAG:Ce and LuAG:Pr scintillator crystals

    CERN Document Server

    Derdzyan, M V; Belsky, A; Dujardin, C; Lecoq, P; Lucchini, M; Ovanesyan, K L; Pauwels, K; Pedrini, C; Petrosyan, A G

    2012-01-01

    Single crystals of LuAG:Ce, LuAG:Pr and un-doped LuAG were grown by the vertical Bridgman method and studied for radiation hardness under gamma-rays with doses in the range 10-10(5) Gy (Co-60). A wide absorption band peaking at around 600 nm springs up in all three types of crystals after the irradiations. The second band peaking at around 375 nm appears in both LuAG:Pr and un-doped LuAG. Compositional variations have been done to reveal the spectral behavior of induced color centers in more detail and to understand their origin. Similarities in behavior of Yb2+ centers in as-grown garnets are found, indicating that radiation induced color centers can be associated with residual trace amounts of Yb present in the raw materials. Un-doped LuAG and LuAG:Ce demonstrate moderate radiation hardness (the induced absorption coefficients being equal to 0.05-0.08 cm(-1) for accumulated doses of 10(3)-10(4) Gy), while LuAG:Pr is less radiation hard. The ways to improve the radiation hardness are discussed.

  18. Axial ion-electron emission microscopy of IC radiation hardness

    Science.gov (United States)

    Doyle, B. L.; Vizkelethy, G.; Walsh, D. S.; Swenson, D.

    2002-05-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV/amu. The electronic stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 μm in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

  19. Radiation-hard silicon gate bulk CMOS cell family

    International Nuclear Information System (INIS)

    Gibbon, C.F.; Habing, D.H.; Flores, R.S.

    1980-01-01

    A radiation-hardened bulk silicon gate CMOS technology and a topologically simple, high-performance dual-port cell family utilizing this process have been demonstrated. Additional circuits, including a random logic circuit containing 4800 transistors on a 236 x 236 mil die, are presently being designed and processed. Finally, a joint design-process effort is underway to redesign the cell family in reduced design rules; this results in a factor of 2.5 cell size reduction and a factor of 3 decrease in chip interconnect area. Cell performance is correspondingly improved

  20. Design of a radiation hard silicon pixel sensor for X-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Schwandt, Joern

    2014-06-15

    At DESY Hamburg the European X-ray Free-Electron Laser (EuXFEL) is presently under construction. The EuXFEL has unique properties with respect to X-ray energy, instantaneous intensity, pulse length, coherence and number of pulses/sec. These properties of the EuXFEL pose very demanding requirements for imaging detectors. One of the detector systems which is currently under development to meet these challenges is the Adaptive Gain Integrating Pixel Detector, AGIPD. It is a hybrid pixel-detector system with 1024 x 1024 p{sup +} pixels of dimensions 200 μm x 200 μm, made of 16 p{sup +}nn{sup +}- silicon sensors, each with 10.52 cm x 2.56 cm sensitive area and 500 μm thickness. The particular requirements for the AGIPD are a separation between noise and single photons down to energies of 5 keV, more than 10{sup 4} photons per pixel for a pulse duration of less than 100 fs, negligible pile-up at the EuXFEL repetition rate of 4.5 MHz, operation for X-ray doses up to 1 GGy, good efficiency for X-rays with energies between 5 and 20 keV, and minimal inactive regions at the edges. The main challenge in the sensor design is the required radiation tolerance and high operational voltage, which is required to reduce the so-called plasma effect. This requires a specially optimized sensor. The X-ray radiation damage results in a build-up of oxide charges and interface traps which lead to a reduction of the breakdown voltage, increased leakage current, increased interpixel capacitances and charge losses. Extensive TCAD simulations have been performed to understand the impact of X-ray radiation damage on the detector performance and optimize the sensor design. To take radiation damage into account in the simulation, radiation damage parameters have been determined on MOS capacitors and gate-controlled diodes as function of dose. The optimized sensor design was fabricated by SINTEF. Irradiation tests on test structures and sensors show that the sensor design is radiation hard and

  1. Radiation-hard optoelectronic data transfer for the CMS tracker

    International Nuclear Information System (INIS)

    Troska, J.K.

    1999-01-01

    An introduction to the physics prospects of future experiments at the CERN Large Hadron Collider (LHC) will be given, along with the rather stringent requirements placed on their detectors by the LHC environment. Emphasis will be placed upon the particle tracking detectors, and the particular problem of their readout systems. The novel analogue optical readout scheme chosen by the Compact Muon Solenoid (CMS) experiment at the LHC will provide the basis for the thesis. The reasons for preferring analogue optical data transmission in CMS will be given, leading to a description of a generic optical readout scheme and its components. The particular scheme chosen by CMS makes as wide as possible use of commercially available components. These will be given greatest importance, with descriptions of component operation and characteristics pertinent to successful readout of the CMS tracker within the constraints of the LHC environment. Of particular concern is the effect of the LHC's harsh radiation environment on the operational characteristics of the readout system and its components. Work on radiation effects in components of the CMS tracker optical readout system will be described. This work includes the effects of ionising (gamma photon) and particle (neutron, proton, pion) irradiation on the operational characteristics and reliability of laser diodes, photodiodes, and optical fibres. System integration issues are discussed in the context of the long-term operation of the full CMS tracker readout system under laboratory conditions. It will be shown that system stability can be maintained even under widely varying ambient conditions. (author)

  2. Radiation hardness of Ce-doped sol-gel silica fibers for high energy physics applications.

    Science.gov (United States)

    Cova, Francesca; Moretti, Federico; Fasoli, Mauro; Chiodini, Norberto; Pauwels, Kristof; Auffray, Etiennette; Lucchini, Marco Toliman; Baccaro, Stefania; Cemmi, Alessia; Bártová, Hana; Vedda, Anna

    2018-02-15

    The results of irradiation tests on Ce-doped sol-gel silica using x- and γ-rays up to 10 kGy are reported in order to investigate the radiation hardness of this material for high-energy physics applications. Sol-gel silica fibers with Ce concentrations of 0.0125 and 0.05 mol. % are characterized by means of optical absorption and attenuation length measurements before and after irradiation. The two different techniques give comparable results, evidencing the formation of a main broad radiation-induced absorption band, peaking at about 2.2 eV, related to radiation-induced color centers. The results are compared with those obtained on bulk silica. This study reveals that an improvement of the radiation hardness of Ce-doped silica fibers can be achieved by reducing Ce content inside the fiber core, paving the way for further material development.

  3. LHCb: Radiation hard programmable delay line for LHCb Calorimeter Upgrade

    CERN Multimedia

    Mauricio Ferre, J; Vilasís Cardona, X; Picatoste Olloqui, E; Machefert, F; Lefrançois, J; Duarte, O

    2013-01-01

    This poster describes the implementation of a SPI-programmable clock delay chip based on a Delay Locked Loop (DLL) in order to shift the phase of the LHC clock (25 ns) in steps of 1ns, with a 4ps jitter and 18ps of DNL. The delay lines will be integrated into ICECAL, the LHCb calorimeter front-end ASIC in the near future. The stringent noise requirements on the ASIC imply minimizing the noise contribution of digital components. This is accomplished by implementing the DLL in differential mode. To achieve the required radiation tolerance several techniques are applied: double guard rings between PMOS and NMOS transistors as well as glitch suppressors and TMR Registers. This 5.7 mm2 chip has been implemented in CMOS 0.35um technology.

  4. Recent results on the development of radiation-hard diamond detectors

    CERN Document Server

    Conway, J S; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Dabrowski, W; Da Graca, J; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Jamieson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernicka, Manfred; Peitz, A; Pirollo, S; Plano, R; Polesello, P; Prawer, S; Pretzl, Klaus P; Procario, M; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Russ, J; Schnetzer, S; Sciortino, S; Somalwar, S V; Speziali, V; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R; Thomson, G B; Trawick, M; Trischuk, W; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; White, C; Ziock, H J; Zöller, M

    1999-01-01

    Charged particle detectors made from chemical vapor deposition (CVD) diamond have radiation hardness greatly exceeding that of silicon- based detectors. The CERN-based RD42 Collaboration has developed and tested CVD diamond microstrip and pixel detectors with an eye to their application in the intense radiation environment near the interaction region of hadron colliders. This paper presents recent results from tests of these detectors. (4 refs).

  5. Radiation hard silicon detectors - developments by the RD48(ROSE) collaboration

    Czech Academy of Sciences Publication Activity Database

    Lindström, G.; Kohout, Z.; Pospíšil, S.; Šícho, Petr; Sopko, B.; Vrba, Václav; Wilhelm, I.

    2001-01-01

    Roč. 466, č. 2 (2001), s. 308-326 ISSN 0168-9002 R&D Projects: GA MŠk LN00A006 Institutional research plan: CEZ:AV0Z1010920 Keywords : silicon detectors * radiation hardness * defect engineering * non ionizing energy los Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.026, year: 2001

  6. Radiation hardness properties of full-3D active edge silicon sensors

    Czech Academy of Sciences Publication Activity Database

    Da Via, C.; Hasi, J.; Kenney, C.; Linhart, V.; Parker, S.; Slavíček, T.; Watts, S. J.; Bém, Pavel; Horažďovský, T.; Pospíšil, S.

    2008-01-01

    Roč. 587, 2-3 (2008), s. 243-249 ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10480505 Keywords : silicon detectors * radiation hardness * 3D Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.019, year: 2008

  7. RD50 Status Report 2008 - Radiation hard semiconductor devices for very high luminosity colliders

    CERN Document Server

    Balbuena, Juan Pablo; Campabadal, Francesca; Díez, Sergio; Fleta, Celeste; Lozano, Manuel; Pellegrini, Giulio; Rafí, Joan Marc; Ullán, Miguel; Creanza, Donato; De Palma, Mauro; Fedele, Francesca; Manna, Norman; Kierstead, Jim; Li, Zheng; Buda, Manuela; Lazanu, Sorina; Pintilie, Lucian; Pintilie, Ioana; Popa, Andreia-Ioana; Lazanu, Ionel; Collins, Paula; Fahrer, Manuel; Glaser, Maurice; Joram, Christian; Kaska, Katharina; La Rosa, Alessandro; Mekki, Julien; Moll, Michael; Pacifico, Nicola; Pernegger, Heinz; Goessling, Claus; Klingenberg, Reiner; Weber, Jens; Wunstorf, Renate; Roeder, Ralf; Stolze, Dieter; Uebersee, Hartmut; Cihangir, Selcuk; Kwan, Simon; Spiegel, Leonard; Tan, Ping; Bruzzi, Mara; Focardi, Ettore; Menichelli, David; Scaringella, Monica; Breindl, Michael; Eckert, Simon; Köhler, Michael; Kuehn, Susanne; Parzefall, Ulrich; Wiik, Liv; Bates, Richard; Blue, Andrew; Buttar, Craig; Doherty, Freddie; Eklund, Lars; Bates, Alison G; Haddad, Lina; Houston, Sarah; James, Grant; Mathieson, Keith; Melone, J; OShea, Val; Parkes, Chris; Pennicard, David; Buhmann, Peter; Eckstein, Doris; Fretwurst, Eckhart; Hönniger, Frank; Khomenkov, Vladimir; Klanner, Robert; Lindström, Gunnar; Pein, Uwe; Srivastava, Ajay; Härkönen, Jaakko; Lassila-Perini, Katri; Luukka, Panja; Mäenpää, Teppo; Tuominen, Eija; Tuovinen, Esa; Eremin, Vladimir; Ilyashenko, Igor; Ivanov, Alexandr; Kalinina, Evgenia; Lebedev, Alexander; Strokan, Nikita; Verbitskaya, Elena; Barcz, Adam; Brzozowski, Andrzej; Kaminski, Pawel; Kozlowski, Roman; Kozubal, Michal; Luczynski, Zygmunt; Pawlowski, Marius; Surma, Barbara; Zelazko, Jaroslaw; de Boer, Wim; Dierlamm, Alexander; Frey, Martin; Hartmann, Frank; Zhukov, Valery; Barabash, L; Dolgolenko, A; Groza, A; Karpenko, A; Khivrich, V; Lastovetsky, V; Litovchenko, P; Polivtsev, L; Campbell, Duncan; Chilingarov, Alexandre; Fox, Harald; Hughes, Gareth; Jones, Brian Keith; Sloan, Terence; Samadashvili, Nino; Tuuva, Tuure; Affolder, Anthony; Allport, Phillip; Bowcock, Themis; Casse, Gianluigi; Vossebeld, Joost; Cindro, Vladimir; Dolenc, Irena; Kramberger, Gregor; Mandic, Igor; Mikuž, Marko; Zavrtanik, Marko; Zontar, Dejan; Gil, Eduardo Cortina; Grégoire, Ghislain; Lemaitre, Vincent; Militaru, Otilia; Piotrzkowski, Krzysztof; Kazuchits, Nikolai; Makarenko, Leonid; Charron, Sébastien; Genest, Marie-Helene; Houdayer, Alain; Lebel, Celine; Leroy, Claude; Aleev, Andrey; Golubev, Alexander; Grigoriev, Eugene; Karpov, Aleksey; Martemianov, Alxander; Rogozhkin, Sergey; Zaluzhny, Alexandre; Andricek, Ladislav; Beimforde, Michael; Macchiolo, Anna; Moser, Hans-Günther; Nisius, Richard; Richter, Rainer; Gorelov, Igor; Hoeferkamp, Martin; Metcalfe, Jessica; Seidel, Sally; Toms, Konstantin; Hartjes, Fred; Koffeman, Els; van der Graaf, Harry; Visschers, Jan; Kuznetsov, Andrej; Sundnes Løvlie, Lars; Monakhov, Edouard; Svensson, Bengt G; Bisello, Dario; Candelori, Andrea; Litovchenko, Alexei; Pantano, Devis; Rando, Riccardo; Bilei, Gian Mario; Passeri, Daniele; Petasecca, Marco; Pignatel, Giorgio Umberto; Bernardini, Jacopo; Borrello, Laura; Dutta, Suchandra; Fiori, Francesco; Messineo, Alberto; Bohm, Jan; Mikestikova, Marcela; Popule, Jiri; Sicho, Petr; Tomasek, Michal; Vrba, Vaclav; Broz, Jan; Dolezal, Zdenek; Kodys, Peter; Tsvetkov, Alexej; Wilhelm, Ivan; Chren, Dominik; Horazdovsky, Tomas; Kohout, Zdenek; Pospisil, Stanislav; Solar, Michael; Sopko, Vít; Sopko, Bruno; Uher, Josef; Horisberger, Roland; Radicci, Valeria; Rohe, Tilman; Bolla, Gino; Bortoletto, Daniela; Giolo, Kim; Miyamoto, Jun; Rott, Carsten; Roy, Amitava; Shipsey, Ian; Son, SeungHee; Demina, Regina; Korjenevski, Sergey; Grillo, Alexander; Sadrozinski, Hartmut; Schumm, Bruce; Seiden, Abraham; Spence, Ned; Hansen, Thor-Erik; Artuso, Marina; Borgia, Alessandra; Lefeuvre, Gwenaelle; Guskov, J; Marunko, Sergey; Ruzin, Arie; Tylchin, Tamir; Boscardin, Maurizio; Dalla Betta, Gian - Franco; Gregori, Paolo; Piemonte, Claudio; Ronchin, Sabina; Zen, Mario; Zorzi, Nicola; Garcia, Carmen; Lacasta, Carlos; Marco, Ricardo; Marti i Garcia, Salvador; Minano, Mercedes; Soldevila-Serrano, Urmila; Gaubas, Eugenijus; Kadys, Arunas; Kazukauskas, Vaidotas; Sakalauskas, Stanislavas; Storasta, Jurgis; Vidmantis Vaitkus, Juozas; CERN. Geneva. The LHC experiments Committee; LHCC

    2010-01-01

    The objective of the CERN RD50 Collaboration is the development of radiation hard semiconductor detectors for very high luminosity colliders, particularly to face the requirements of a possible upgrade scenario of the LHC.This document reports the status of research and main results obtained after the sixth year of activity of the collaboration.

  8. The chemistry of two-component fluoride crystalline optical media for heavy, fast, radiation hard scintillators

    International Nuclear Information System (INIS)

    Sobolev, B.P.; Krivandina, E.A.; Fedorov, P.P.; Vasilchenko, V.G.

    1994-01-01

    Prospects for preparation of two-component dense optical materials for scintillators are shown, using data on phase diagrams of about 300 MF m - RF n (m, n ≤ 4) type systems, formed by metal fluorides. Primary characteristics (decay time and light output of luminescence, radiation hardness, etc.) of some multicomponent crystals are reported

  9. RD50 Status Report 2009/2010 - Radiation hard semiconductor devices for very high luminosity colliders

    CERN Document Server

    Moll, Michael

    2012-01-01

    The objective of the CERN RD50 Collaboration is the development of radiation hard semiconductor detectors for very high luminosity colliders, particularly to face the requirements for the upgrade of the LHC detectors. This document reports on the status of research and main results obtained in the years 2009 and 2010.

  10. Shared Task System Description: Frustratingly Hard Compositionality Prediction

    DEFF Research Database (Denmark)

    Johannsen, Anders Trærup; Martinez Alonso, Hector; Rishøj, Christian

    2011-01-01

    , and the likelihood of long translation equivalents in other languages. Many of the features we considered correlated significantly with human compositionality scores, but in support vector regression experiments we obtained the best results using only COALS-based endocentricity scores. Our system was nevertheless......We considered a wide range of features for the DiSCo 2011 shared task about compositionality prediction for word pairs, including COALS-based endocentricity scores, compositionality scores based on distributional clusters, statistics about wordnet-induced paraphrases, hyphenation...

  11. Predicting the Performance of Chain Saw Machines Based on Shore Scleroscope Hardness

    Science.gov (United States)

    Tumac, Deniz

    2014-03-01

    Shore hardness has been used to estimate several physical and mechanical properties of rocks over the last few decades. However, the number of researches correlating Shore hardness with rock cutting performance is quite limited. Also, rather limited researches have been carried out on predicting the performance of chain saw machines. This study differs from the previous investigations in the way that Shore hardness values (SH1, SH2, and deformation coefficient) are used to determine the field performance of chain saw machines. The measured Shore hardness values are correlated with the physical and mechanical properties of natural stone samples, cutting parameters (normal force, cutting force, and specific energy) obtained from linear cutting tests in unrelieved cutting mode, and areal net cutting rate of chain saw machines. Two empirical models developed previously are improved for the prediction of the areal net cutting rate of chain saw machines. The first model is based on a revised chain saw penetration index, which uses SH1, machine weight, and useful arm cutting depth as predictors. The second model is based on the power consumed for only cutting the stone, arm thickness, and specific energy as a function of the deformation coefficient. While cutting force has a strong relationship with Shore hardness values, the normal force has a weak or moderate correlation. Uniaxial compressive strength, Cerchar abrasivity index, and density can also be predicted by Shore hardness values.

  12. Intelligent optimization models based on hard-ridge penalty and RBF for forecasting global solar radiation

    International Nuclear Information System (INIS)

    Jiang, He; Dong, Yao; Wang, Jianzhou; Li, Yuqin

    2015-01-01

    Highlights: • CS-hard-ridge-RBF and DE-hard-ridge-RBF are proposed to forecast solar radiation. • Pearson and Apriori algorithm are used to analyze correlations between the data. • Hard-ridge penalty is added to reduce the number of nodes in the hidden layer. • CS algorithm and DE algorithm are used to determine the optimal parameters. • Proposed two models have higher forecasting accuracy than RBF and hard-ridge-RBF. - Abstract: Due to the scarcity of equipment and the high costs of maintenance, far fewer observations of solar radiation are made than observations of temperature, precipitation and other weather factors. Therefore, it is increasingly important to study several relevant meteorological factors to accurately forecast solar radiation. For this research, monthly average global solar radiation and 12 meteorological parameters from 1998 to 2010 at four sites in the United States were collected. Pearson correlation coefficients and Apriori association rules were successfully used to analyze correlations between the data, which provided a basis for these relative parameters as input variables. Two effective and innovative methods were developed to forecast monthly average global solar radiation by converting a RBF neural network into a multiple linear regression problem, adding a hard-ridge penalty to reduce the number of nodes in the hidden layer, and applying intelligent optimization algorithms, such as the cuckoo search algorithm (CS) and differential evolution (DE), to determine the optimal center and scale parameters. The experimental results show that the proposed models produce much more accurate forecasts than other models

  13. Monitoring system for testing the radiation hardness of a KINTEX-7 FPGA

    Energy Technology Data Exchange (ETDEWEB)

    Cojocariu, L. N., E-mail: lucian.cojocariu@cern.ch [Horia Hulubei National Institute for R& D in Physics and Nuclear Engineering (Reactorului 30, MG, Romania) (Romania); Stefan cel Mare University of Suceava (Universitatii 13, Suceava, Romania) (Romania); Placinta, V. M., E-mail: vlad-mihai.placinta@cern.ch [Horia Hulubei National Institute for R& D in Physics and Nuclear Engineering (Reactorului 30, MG, Romania) (Romania); University POLITEHNICA of Bucharest (Splaiul Independentei 313, Bucharest, Romania) (Romania); Dumitru, L., E-mail: dlaur@nipne.ro [Horia Hulubei National Institute for R& D in Physics and Nuclear Engineering (Reactorului 30, MG, Romania) (Romania)

    2016-03-25

    A much more efficient Ring Imaging Cherenkov sub-detector system will be rebuilt in the second long shutdown of Large Hadron Collider for the LHCb experiment. Radiation-hard electronic components together with Commercial Off-The-Shelf ones will be used in the new Cherenkov photon detection system architecture. An irradiation program was foreseen to determine the radiation tolerance for the new electronic devices, including a Field Programmable Gate Array from KINTEX-7 family of XILINX. An automated test bench for online monitoring of the XC7K70T KINTEX-7 device operation in radiation conditions was designed and implemented by the LHCb Romanian group.

  14. Process and devices of detection of hard electromagnetic or particle radiations using a superconducting element

    International Nuclear Information System (INIS)

    Drukier, A.K.; Valette, Claude; Waysand, Georges.

    1975-01-01

    The invention relates to processes and systems for the detection of hard electromagnetic or particle radiations and the sensors fitted to these systems. 'Hard radiations' means those whose energy is greater than a variable threshold, depending on the applications, but always more than 5 keV. The use of these sensors and the associated systems can therefore be envisaged in radiography and also in emission gammagraphy in the biological, anatomic and medical fields. In these processes, in order to detect a photon or a radiation particle, use is made of the transition phenomenon of a homogeneous grain of superconducting material of the first kind, from the metastable superconducting state to the normal state, under the effect of a photoelectron ejected by the impact of the photon or of the particle on the grain of superconducting material [fr

  15. Performance And Radiation Hardness Of The Atlas/sct Detector Module

    CERN Document Server

    Eklund, L

    2003-01-01

    The ATLAS experiment is a general purpose experiment being constructed at the Large Hadron Collider (LHC) at FERN, Geneva. ATLAS is designed to exploit the full physics potential of LHC, in particular to study topics concerning the Higgs mechanism, Super-symmetry and CP violation. The cross sections for the processes under study are extremely small, requiring very high luminosity colliding beams. The Semiconductor Tracker (SCT) is an essential part of the Inner Detector tracking system of ATLAS. The active elements of the SCT is 4088 detector modules, tiled on four barrel cylinders and eighteen endcap disks. As a consequence of the high luminosity, the detector modules will operate in a harsh radiation environment. This thesis describes work concerning radiation hardness, beam test performance and methods for production testing of detector modules. The radiation hardness studies have been focused on the electrical performance of the front-end ASIC and the detector module. The results have identified features ...

  16. Effects of plasma-deposited silicon nitride passivation on the radiation hardness of CMOS integrated circuits

    International Nuclear Information System (INIS)

    Clement, J.J.

    1980-01-01

    The use of plasma-deposited silicon nitride as a final passivation over metal-gate CMOS integrated circuits degrades the radiation hardness of these devices. The hardness degradation is manifested by increased radiation-induced threshold voltage shifts caused principally by the charging of new interface states and, to a lesser extent, by the trapping of holes created upon exposure to ionizing radiation. The threshold voltage shifts are a strong function of the deposition temperature, and show very little dependence on thickness for films deposited at 300 0 C. There is some correlation between the threshold voltage shifts and the hydrogen content of the PECVD silicon nitride films used as the final passivation layer as a function of deposition temperature. The mechanism by which the hydrogen contained in these films may react with the Si/SiO 2 interface is not clear at this point

  17. R and D on Radiation Hard Active Media Based on Quartz Plates

    CERN Document Server

    Onel, Yasar

    2014-01-01

    The need for radiation-hard active media in particle detectors is prominently dictated by the future colliders and the future operations of the Large Hadron Collider. The areas of implementation range from calorimetry to beamline instrumentation to specialized forward detectors e.g. luminosity monitors. In this context, we developed the idea of utilizing quartz plates with various surface coating properties as the active medium for such detectors. Plain quartz is a pure Cerenkov radiator which has quite limited photostatistics. In order to improve the efficiency of the photodetection, various methods were investigated including radiation hard wavelength shifters, p-terphenyl or 4pct gallium doped zinc oxide. The readout options include direct coupling of the photodetector to the quartz plate, or fibers. We have studied various geometries and readout options and constructed calorimeter prototypes. Here we report on the results of the previous tests, and the recent developments, which enable several factors of ...

  18. Extreme Radiation Hardness and Space Qualification of AlGaN Optoelectronic Devices

    International Nuclear Information System (INIS)

    Sun, Ke-Xun; MacNeil, Lawrence; Balakrishnan, Kathik; Hultgren, Eric; Goebel, John; Bilenko, Yuri; Yang, Jinwei; Sun, Wenhong; Shatalov, Max; Hu, Xuhong; Gaska, Remis

    2010-01-01

    Unprecedented radiation hardness and environment robustness are required in the new generation of high energy density physics (HEDP) experiments and deep space exploration. National Ignition Facility (NIF) break-even shots will have a neutron yield of 10 15 or higher. The Europa Jupiter System Mission (EJSM) mission instruments will be irradiated with a total fluence of 10 12 protons/cm 2 during the space journey. In addition, large temperature variations and mechanical shocks are expected in these applications under extreme conditions. Hefty radiation and thermal shields are required for Si and GaAs based electronics and optoelectronics devices. However, for direct illumination and imaging applications, shielding is not a viable option. It is an urgent task to search for new semiconductor technologies and to develop radiation hard and environmentally robust optoelectronic devices. We will report on our latest systematic experimental studies on radiation hardness and space qualifications of AlGaN optoelectronic devices: Deep UV Light Emitting Diodes (DUV LEDs) and solarblind UV Photodiodes (PDs). For custom designed AlGaN DUV LEDs with a central emission wavelength of 255 nm, we have demonstrated its extreme radiation hardness up to 2 x 10 12 protons/cm 2 with 63.9 MeV proton beams. We have demonstrated an operation lifetime of over 26,000 hours in a nitrogen rich environment, and 23,000 hours of operation in vacuum without significant power drop and spectral shift. The DUV LEDs with multiple packaging styles have passed stringent space qualifications with 14 g random vibrations, and 21 cycles of 100K temperature cycles. The driving voltage, current, emission spectra and optical power (V-I-P) operation characteristics exhibited no significant changes after the space environmental tests. The DUV LEDs will be used for photoelectric charge management in space flights. For custom designed AlGaN UV photodiodes with a central response wavelength of 255 nm, we have

  19. Predicted solar cell edge radiation effects

    International Nuclear Information System (INIS)

    Gates, M.T.

    1993-01-01

    The Advanced Solar Cell Orbital Test (ASCOT) will test six types of solar cells in a high energy proton environment. During the design of the experiment a question was raised about the effects of proton radiation incident on the edge of the solar cells and whether edge radiation shielding was required. Historical geosynchronous data indicated that edge radiation damage is not detectable over the normal end of life solar cell degradation; however because the ASCOT radiation environment has a much higher and more energetic fluence of protons, considerably more edge damage is expected. A computer analysis of the problem was made by modeling the expected radiation damage at the cell edge and using a network model of small interconnected solar cells to predict degradation in the cell's electrical output. The model indicated that the deepest penetration of edge radiation was at the top of the cell near the junction where the protons have access to the cell through the low density cell/cover adhesive layer. The network model indicated that the cells could tolerate high fluences at their edge as long as there was high electrical resistance between the edge radiated region and the contact system on top of the cell. The predicted edge radiation related loss was less than 2% of maximum power for GaAs/Ge solar cells. As a result, no edge radiation protection was used for ASCOT

  20. Hardness prediction of HAZ in temper bead welding by non-consistent layer technique

    International Nuclear Information System (INIS)

    Yu, Lina; Saida, Kazuyoshi; Mochizuki, Masahito; Kameyama, Masashi; Chigusa, Naoki; Nishimoto, Kazutoshi

    2014-01-01

    Based on the experimentally obtained hardness database, the neural network-based hardness prediction system of heat affect zone (HAZ) in temper bead welding by Consistent Layer (CSL) technique has been constructed by the authors. However in practical operation, CSL technique is sometimes difficult to perform because of difficulty of the precise heat input controlling, and in such case non-CSL techniques are mainly used in the actual repair process. Therefore in the present study, the neural network-based hardness prediction system of HAZ in temper bead welding by non-CSL techniques has been constructed through thermal cycle simplification, from the view of engineering. The hardness distribution in HAZ with non-CSL techniques was calculated based on the thermal cycles numerically obtained by finite element method. The experimental result has shown that the predicted hardness is in good accordance with the measured ones. It follows that the currently proposed method is effective for estimating the tempering effect during temper bead welding by non-CSL techniques. (author)

  1. Study of runaway electrons using dosimetry of hard x-ray radiations in Damavand tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Rasouli, C.; Pourshahab, B.; Rasouli, H. [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Hosseini Pooya, S. M.; Orouji, T. [Radiation Application Research School, Nuclear Science and Technology Research Institute, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)

    2014-05-15

    In this work several studies have been conducted on hard x-ray emissions of Damavand tokamak based on radiation dosimetry using the Thermoluminescence method. The goal was to understand interactions of runaway electrons with plasma particles, vessel wall, and plasma facing components. Total of 354 GR-200 (LiF:Mg,Cu,P) thermoluminescence dosimeter (TLD) crystals have been placed on 118 points – three TLDs per point – to map hard x-ray radiation doses on the exterior of the vacuum vessel. Results show two distinctive levels of x-ray radiations doses on the exterior of the vessel. The low-dose area on which measured dose is about 0.5 mSv/shot. In the low-dose area there is no particular component inside the vessel. On the contrary, on high-dose area of the vessel, x-ray radiations dose exceeds 30 mSv/shot. The high-dose area coincides with the position of limiters, magnetic probe ducts, and vacuum vessel intersections. Among the high-dose areas, the highest level of dose is measured in the position of the limiter, which could be due to its direct contact with the plasma column and with runaway electrons. Direct collisions of runaway electrons with the vessel wall and plasma facing components make a major contribution for production of hard x-ray photons in Damavand tokamak.

  2. A top-down approach for the prediction of hardness and toughness of hierarchical materials

    International Nuclear Information System (INIS)

    Carpinteri, Alberto; Paggi, Marco

    2009-01-01

    Many natural and man-made materials exhibit structure over more than one length scale. In this paper, we deal with hierarchical grained composite materials that have recently been designed to achieve superior hardness and toughness as compared to their traditional counterparts. Their nested structure, where meso-grains are recursively composed of smaller and smaller micro-grains at the different scales with a fractal-like topology, is herein studied from a hierarchical perspective. Considering a top-down approach, i.e. from the largest to the smallest scale, we propose a recursive micromechanical model coupled with a generalized fractal mixture rule for the prediction of hardness and toughness of a grained material with n hierarchical levels. A relationship between hardness and toughness is also derived and the analytical predictions are compared with experimental data.

  3. RD50 recent results: Development of radiation hard sensors for SLHC

    CERN Document Server

    Macchiolo, Anna

    2009-01-01

    The need for radiation hard semiconductor detectors for the tracker regions in high energy physics experiments at a future high luminosity hadron collider, like the proposed LHC upgrade, has led to the formation of the CERN RD50 collaboration. The R&D directions of RD50 follow two paths: the optimization of radiation hard bulk materials (Material Engineering) and the development of new detector designs (Device Engineering) as 3D sensors, thin sensors and n-in-p sensors. Some of the RD50 most recent results about silicon detectors are reported in this paper, with special reference to: (i) identification of defects responsible for long term annealing, (ii) charge collection efficiency of irradiated planar devices, in particular n-in-p microstrip detectors and epitaxial diodes, (iii) charge collection efficiency of double-type column 3D detectors, (iv) comparison of the performances of FZ and MCZ structures under mixed irradiation.

  4. Development and Studies of Novel Microfabricated Radiation Hard Scintillation Detectors With High Spatial Resolution

    CERN Document Server

    Mapelli, A; Haguenauer, M; Jiguet, S; Renaud, P; Vico Triviño, N

    2011-01-01

    A new type of scintillation detector is being developed with standard microfabrication techniques. It consists of a dense array of scintillating waveguides obtained by coupling microfluidic channels filled with a liquid scintillator to photodetectors. Easy manipulation of liquid scintillators inside microfluidic devices allow their flushing, renewal, and exchange making the active medium intrinsically radiation hard. Prototype detectors have been fabricated by photostructuration of a radiation hard epoxy resin (SU-8) deposited on silicon wafers and coupled to a multi-anode photomultiplier tube (MAPMT) to read-out the scintillation light. They have been characterized by exciting the liquid scintillator in the 200 micrometers thick microchannels with electrons from a 90Sr yielding approximately 1 photoelectron per impinging Minimum Ionizing Particle (MIP). These promising results demonstrate the concept of microfluidic scintillating detection and are very encouraging for future developments.

  5. Hard synchrotron radiation scattering from a nonideal surface grating from multilayer X-ray mirrors

    International Nuclear Information System (INIS)

    Punegov, V.I.; Nesterets, Ya.I.; Mytnichenko, S.V.; Kovalenko, N.V.; Chernov, V.A.

    2003-01-01

    The hard synchrotron radiation scattering from a multilayer surface grating is theoretically and experimentally investigated. The numerical calculations of angular distribution of scattering intensity from X-ray mirror Ni/C are executed with use of recurrence formulae and statistical dynamical theory of diffraction. It is shown, that the essential role in formation of a diffraction pattern plays a diffuse scattering caused by structure imperfection of a multilayer grating [ru

  6. Silicon Photo-Multiplier Radiation Hardness Tests with a White Neutron Beam

    International Nuclear Information System (INIS)

    Montanari, A.; Tosi, N.; Pietropaolo, A.; Andreotti, M.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Luppi, E.; Cotta Ramusino, A.; Malaguti, R.; Santoro, V.; Tellarini, G.; Tomassetti, L.; De Donato, C.; Reali, E.

    2013-06-01

    We report radiation hardness tests performed, with a white neutron beam, at the Geel Electron Linear Accelerator in Belgium on silicon Photo-Multipliers. These are semiconductor photon detectors made of a square matrix of Geiger-Mode Avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated integrating up to about 6.2 x 10 9 1-MeV-equivalent neutrons per cm 2 . (authors)

  7. A Radiation-Hard Analog Memory In The AVLSI-RA Process

    International Nuclear Information System (INIS)

    Britton, C.L. Jr.; Wintenberg, A.L.; Read, K.F.; Simpson, M.L.; Young, G.R.; Clonts, L.G.; Kennedy, E.J.; Smith, R.S.; Swann, B.K.; Musser, J.A.

    1995-01-01

    A radiation hardened analog memory for an Interpolating Pad Camber has been designed at Oak Ridge National Laboratory and fabricated by Harris Semiconductor in the AVLSI-RA CMOS process. The goal was to develop a rad-hard analog pipeline that would deliver approximately 9-bit performance, a readout settling time of 500ns following read enable, an input and output dynamic range of +/-2.25V, a corrected rms pedestal of approximately 5mV or less, and a power dissipation of less than 10mW/channel. The pre- and post-radiation measurements to 5MRad are presented

  8. System tests of radiation hard optical links for the ATLAS semiconductor tracker

    International Nuclear Information System (INIS)

    Charlton, D.G.; Dowell, J.D.; Homer, R.J.; Jovanovic, P.; Kenyon, I.R.; Mahout, G.; Shaylor, H.R.; Wilson, J.A.; Rudge, A.; Fopma, J.; Mandic, I.; Nickerson, R.B.; Shield, P.; Wastie, R.; Weidberg, A.R.; Eek, L.-O.; Go, A.; Lund-Jensen, B.; Pearce, M.; Soederqvist, J.; Morrissey, M.; White, D.J.

    2000-01-01

    A prototype optical data and Timing, Trigger and Control transmission system based on LEDs and PIN-diodes has been constructed. The system would be suitable in terms of radiation hardness and radiation length for use in the ATLAS SemiConductor Tracker. Bit error rate measurements were performed for the data links and for the links distributing the Timing, Trigger and Control data from the counting room to the front-end modules. The effects of cross-talk between the emitters and receivers were investigated. The advantages of using Vertical Cavity Surface Emitting Lasers (VCSELs) instead of LEDs are discussed

  9. Radiation hard silicon particle detectors for HL-LHC—RD50 status report

    Energy Technology Data Exchange (ETDEWEB)

    Terzo, S., E-mail: Stefano.Terzo@mpp.mpg.de

    2017-02-11

    It is foreseen to significantly increase the luminosity of the LHC by upgrading towards the HL-LHC (High Luminosity LHC). The Phase-II-Upgrade scheduled for 2024 will mean unprecedented radiation levels, way beyond the limits of the silicon trackers currently employed. All-silicon central trackers are being studied in ATLAS, CMS and LHCb, with extremely radiation hard silicon sensors to be employed on the innermost layers. Within the RD50 Collaboration, a massive R&D program is underway across experimental boundaries to develop silicon sensors with sufficient radiation tolerance. We will present results of several detector technologies and silicon materials at radiation levels corresponding to HL-LHC fluences. Based on these results, we will give recommendations for the silicon detectors to be used at the different radii of tracking systems in the LHC detector upgrades. In order to complement the measurements, we also perform detailed simulation studies of the sensors. - Highlights: • The RD50 collaboration investigates the radiation hardness of silicon sensors. • Different approaches to simulate the detector response after irradiation are shown. • HV-CMOS are cost-effective solution for the outer pixel layers at HL-LHC. • 3D and thin planar sensors with slim edges are solutions for innermost layers at HL-LHC. • Sensors with intrinsic gain are investigated to develop ultra-fast silicon detectors.

  10. Comparison of proton microbeam and gamma irradiation for the radiation hardness testing of silicon PIN diodes

    Science.gov (United States)

    Jakšić, M.; Grilj, V.; Skukan, N.; Majer, M.; Jung, H. K.; Kim, J. Y.; Lee, N. H.

    2013-09-01

    Simple and cost-effective solutions using Si PIN diodes as detectors are presently utilized in various radiation-related applications in which excessive exposure to radiation degrades their charge transport properties. One of the conventional methods for the radiation hardness testing of such devices is time-consuming irradiation with electron beam or gamma-ray irradiation facilities, high-energy proton accelerators, or with neutrons from research reactors. Recently, for the purpose of radiation hardness testing, a much faster nuclear microprobe based approach utilizing proton irradiation has been developed. To compare the two different irradiation techniques, silicon PIN diodes have been irradiated with a Co-60 gamma radiation source and with a 6 MeV proton microbeam. The signal degradation in the silicon PIN diodes for both irradiation conditions has been probed by the IBIC (ion beam induced charge) technique, which can precisely monitor changes in charge collection efficiency. The results presented are reviewed on the basis of displacement damage calculations and NIEL (non-ionizing energy loss) concept.

  11. A novel method to predict the highest hardness of plasma sprayed coating without micro-defects

    Science.gov (United States)

    Zhuo, Yukun; Ye, Fuxing; Wang, Feng

    2018-04-01

    The plasma sprayed coatings are stacked by splats, which are regarded generally as the elementary units of coating. Many researchers have focused on the morphology and formation mechanism of splat. However, a novel method to predict the highest hardness of plasma sprayed coating without micro-defects is proposed according to the nanohardness of splat in this paper. The effectiveness of this novel method was examined by experiments. Firstly, the microstructure of splats and coating, meanwhile the 3D topography of the splats were observed by SEM (SU1510) and video microscope (VHX-2000). Secondly, the nanohardness of splats was evaluated by nanoindentation (NHT) in order to be compared with microhardness of coating measured by microhardness tester (HV-1000A). The results show that the nanohardness of splats with diameter of 70 μm, 100 μm and 140 μm were in the scope of 11∼12 GPa while the microhardness of coating were in the range of 8∼9 GPa. Because the splats had not micro-defects such as pores and cracks in the nanohardness evaluated nano-zone, the nanohardness of the splats can be utilized to predict the highest hardness of coating without micro-defects. This method indicates the maximum of sprayed coating hardness and will reduce the test number to get high hardness coating for better wear resistance.

  12. Uncooled Radiation Hard Large Area SiC X-ray and EUV Detectors and 2D Arrays, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to design, fabricate, characterize and commercialize large area, uncooled and radiative hard 4H-SiC EUV ? soft X-ray detectors capable of ultra...

  13. Systems for detecting and recording hard corpuscular and electromagnetic radiations using a superconducting element

    International Nuclear Information System (INIS)

    Drukier, A.K.; Valette, Claude; Waysand, Georges.

    1975-01-01

    The invention relates to systems for detecting hard X ray or gamma radiations above 5 keV in energy, intended, for example, for gammagraphy by emission in the biological, anatomic and medical fields. It describes systems of the above type which directly give the image of a radiation distribution, that is to say without intermediate processing. Another purpose of the invention is to provide the devices with main memory measuring the radiation distribution, in other words systems that display the said data for as long as the operator deems necessary and that can be reset, that is to say returned to measuring conditions, immediately. The invention makes use of the properties of type I superconductors [fr

  14. Electrical properties and radiation hardness of SOI systems with multilayer buried dielectric

    International Nuclear Information System (INIS)

    Barchuk, I.P.; Kilchitskaya, V.I.; Lysenko, V.S.

    1997-01-01

    In this work SOI structures with buried SiO 2 -Si 3 N 4 -SiO 2 layers have been fabricated by the ZMR-technique with the aim of improving the total dose radiation hardness of the buried dielectric layer. To optimize the fabrication process, buried layers were investigated by secondary ion mass spectrometry before and after the ZMR process, and the obtained results were compared with electrical measurements. It is shown that optimization of the preparation processes of the initial buried dielectric layers provides ZMR SOI structures with multilayer buried isolation, which are of high quality for both Si film interfaces. Particular attention is paid to the investigation of radiation-induced charge trapping in buried insulators. Buried isolation structures with a nitride layer exhibit significant reduction of radiation-induced positive charge as compared to classical buried SiO 2 layers produced by either the ZMR or the SIMOX technique

  15. Radiation hardness tests of SiPMs for the JLab Hall D Barrel calorimeter

    International Nuclear Information System (INIS)

    Qiang, Yi; Zorn, Carl; Barbosa, Fernando; Smith, Elton

    2013-01-01

    We report on the measurement of the neutron radiation hardness of silicon photomultipliers (SiPMs) manufactured by Hamamatsu Corporation in Japan and SensL in Ireland. Samples from both companies were irradiated by neutrons created by a 1 GeV electron beam hitting a thin lead target at Jefferson Lab Hall A. More tests regarding the temperature dependence of the neutron radiation damage and self-annealing were performed on Hamamatsu SiPMs using a calibrated Am–Be neutron source from the Jefferson Lab Radiation Control group. As the result of irradiation both dark current and dark rate increase linearly as a function of the 1 MeV equivalent neutron fluence and a temperature dependent self-annealing effect is observed.

  16. Radiation hardness of GaAs sensors against gamma-rays, neutrons and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Šagátová, Andrea, E-mail: andrea.sagatova@stuba.sk [Institute of Nuclear and Physical Engineering, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava (Slovakia); University Centre of Electron Accelerators, Slovak Medical University, Ku kyselke 497, 911 06 Trenčín (Slovakia); Zaťko, Bohumír; Dubecký, František [Institute of Electrical Engineering, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava (Slovakia); Ly Anh, Tu [Faculty of Applied Science, University of Technology VNU HCM, 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City (Viet Nam); Nečas, Vladimír; Sedlačková, Katarína; Pavlovič, Márius [Institute of Nuclear and Physical Engineering, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovičova 3, 812 19 Bratislava (Slovakia); Fülöp, Marko [University Centre of Electron Accelerators, Slovak Medical University, Ku kyselke 497, 911 06 Trenčín (Slovakia)

    2017-02-15

    Highlights: • Radiation hardness of SI GaAs detectors against gamma-rays, neutrons and electrons was compared. • Good agreement was achieved between the experimental results and displacement damage factor of different types of radiation. • CCE and FWHM first slightly improved (by 1–8%) and just then degraded with the cumulative dose. • An increase of detection efficiency with cumulative dose was observed. - Abstract: Radiation hardness of semi-insulating GaAs detectors against {sup 60}Co gamma-rays, fast neutrons and 5 MeV electrons was compared. Slight improvements in charge collection efficiency (CCE) and energy resolution in FWHM (Full Width at Half Maximum) were observed at low doses with all kinds of radiation followed by their degradation. The effect occurred at a dose of about 10 Gy of neutrons (CCE improved by 1%, FWHM by 5% on average), at 1 kGy of electrons (FWHM decreased by 3% on average) and at 10 kGy of gamma-rays (CCE raised by 5% and FWHM dropped by 8% on average), which is in agreement with the relative displacement damage of the used types of radiation. Gamma-rays of MeV energies are 1000-times less damaging than similar neutrons and electrons about 10-times more damaging than photons. On irradiating the detectors with neutrons and electrons, we observed a global increase in their detection efficiency, which was caused probably by enlargement of the active detector area as a consequence of created radiation defects in the base material. Detectors were still functional after a dose of 1140 kGy of ∼1 MeV photons, 104 kGy of 5 MeV electrons but only up to 0.576 kGy of fast (∼2 to 30 MeV) neutrons.

  17. Mathematical model of heat transfer to predict distribution of hardness through the Jominy bar

    International Nuclear Information System (INIS)

    Lopez, E.; Hernandez, J. B.; Solorio, G.; Vergara, H. J.; Vazquez, O.; Garnica, F.

    2013-01-01

    The heat transfer coefficient was estimated at the bottom surface at Jominy bar end quench specimen by solution of the heat inverse conduction problem. A mathematical model based on the finite-difference method was developed to predict thermal paths and volume fraction of transformed phases. The mathematical model was codified in the commercial package Microsoft Visual Basic v. 6. The calculated thermal path and final phase distribution were used to evaluate the hardness distribution along the AISI 4140 Jominy bar. (Author)

  18. The influence of parotid gland sparing on radiation damages of dental hard tissues.

    Science.gov (United States)

    Hey, Jeremias; Seidel, Johannes; Schweyen, Ramona; Paelecke-Habermann, Yvonne; Vordermark, Dirk; Gernhardt, Christian; Kuhnt, Thomas

    2013-07-01

    The aim of the present study was to evaluate whether radiation damage on dental hard tissue depends on the mean irradiation dose the spared parotid gland is subjected to or on stimulated whole salivary flow rate. Between June 2002 and October 2008, 70 patients with neck and cancer curatively irradiated were included in this study. All patients underwent dental treatment referring to the guidelines and recommendations of the German Society of Dental, Oral and Craniomandibular Sciences prior, during, and after radiotherapy (RT). During the follow-up period of 24 months, damages on dental hard tissues were classified according to the RTOG/EORTC guidelines. The mean doses (D(mean)) during spared parotid gland RT were determined. Stimulated whole saliva secretion flow rates (SFR) were measured before RT and 1, 6, 12, 24 months after RT. Thirty patients showed no carious lesions (group A), 18 patients developed sporadic carious lesions (group B), and 22 patients developed general carious lesions (group C). Group A patients received a D mean of 21.2 ± 11.04 Gy. Group B patients received a D(mean) of 26.5 ± 11.59 Gy and group C patients received a D(mean) of 33.9 ± 9.93 Gy, respectively. The D(mean) of group A was significantly lower than the D(mean) of group C (p dental hard tissue correlates with increased mean irradiation doses as well as decreased salivary flow rates. Parotid gland sparing resulting in a dose below 20 Gy reduces radiation damage on dental hard tissues, and therefore, the dose may act as a predictor for the damage to be expected.

  19. Development of radiation-hard optical links for the CMS tracker at CERN

    International Nuclear Information System (INIS)

    Vasey, F.; Arbet-Engels, V.; Cervelli, G.; Gill, K.; Grabit, R.; Mommaert, C.; Stefanini, G.

    1998-01-01

    A radiation-hard optical link is under development for readout and control of the tracking detector in the future CMS experiment at the CERN Large Hadron Collider. The authors present the optical system architecture based on edge-emitting InGaAsP laser-diode transmitters operating at a wavelength of 1.3 microm, single mode fiber ribbons, multi-way connectors and InGaAsP in photodiode receivers. They report on radiation hardness tests of lasers, photodiodes, fibers and connectors. Increases of laser threshold and pin leakage currents with hadron fluence have been observed together with decreases in laser slope-efficiency and photodiode responsivity. Short lengths of single-mode optical fiber and multi-way connectors have been found to be little affected by radiation damage. They analyze the analog and digital performance of prototype optical links transmitting data generated at a 40 MSample/s rate. Distortion, settling time, bandwidth, noise, dynamic range and bit-error-rate results are discussed

  20. A Demonstrator Analog Signal Processing Circuit in a Radiation Hard SOI-CMOS Technology

    CERN Multimedia

    2002-01-01

    % RD-9 A Demonstrator Analog Signal Processing Circuit in a Radiation Hard SOI-CMOS Technology \\\\ \\\\Radiation hardened SOI-CMOS (Silicon-On-Insulator, Complementary Metal-Oxide- \\linebreak Semiconductor planar microelectronic circuit technology) was a likely candidate technology for mixed analog-digital signal processing electronics in experiments at the future high luminosity hadron colliders. We have studied the analog characteristics of circuit designs realized in the Thomson TCS radiation hard technologies HSOI3-HD. The feature size of this technology was 1.2 $\\mu$m. We have irradiated several devices up to 25~Mrad and 3.10$^{14}$ neutrons cm$^{-2}$. Gain, noise characteristics and speed have been measured. Irradiation introduces a degradation which in the interesting bandwidth of 0.01~MHz~-~1~MHz is less than 40\\%. \\\\ \\\\Some specific SOI phenomena have been studied in detail, like the influence on the noise spectrum of series resistence in the thin silicon film that constitutes the body of the transistor...

  1. Radiation hardness of a single crystal CVD diamond detector for MeV energy protons

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yuki, E-mail: y.sato@riken.jp [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Shimaoka, Takehiro; Kaneko, Junichi H. [Graduate School of Engineering, Hokkaido University, N13, W8, Sapporo 060-8628 (Japan); Murakami, Hiroyuki [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Isobe, Mitsutaka; Osakabe, Masaki [National Institute for Fusion Science, 322-6, Oroshi-cho Toki-city, Gifu 509-5292 (Japan); Tsubota, Masakatsu [Graduate School of Engineering, Hokkaido University, N13, W8, Sapporo 060-8628 (Japan); Ochiai, Kentaro [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Chayahara, Akiyoshi; Umezawa, Hitoshi; Shikata, Shinichi [National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

    2015-06-01

    We have fabricated a particle detector using single crystal diamond grown by chemical vapor deposition. The irradiation dose dependence of the output pulse height from the diamond detector was measured using 3 MeV protons. The pulse height of the output signals from the diamond detector decreases as the amount of irradiation increases at count rates of 1.6–8.9 kcps because of polarization effects inside the diamond crystal. The polarization effect can be cancelled by applying a reverse bias voltage, which restores the pulse heights. Additionally, the radiation hardness performance for MeV energy protons was compared with that of a silicon surface barrier detector.

  2. Silicon photo-multiplier radiation hardness tests with a beam controlled neutron source

    International Nuclear Information System (INIS)

    Angelone, M.; Pillon, M.; Faccini, R.; Pinci, D.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Cotta Ramusino, A.; Malaguti, R.; Pozzati, M.

    2010-01-01

    Radiation hardness tests were performed at the Frascati Neutron Generator on silicon Photo-Multipliers that were made of semiconductor photon detectors built from a square matrix of avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated, integrating up to 7x10 10 1-MeV-equivalent neutrons per cm 2 . Detector performance was recorded during the neutron irradiation, and a gradual deterioration of their properties began after an integrated fluence of the order of 10 8 1-MeV-equivalent neutrons per cm 2 was reached.

  3. Radiation hardness of silicon detectors manufactured on wafers from various sources

    International Nuclear Information System (INIS)

    Dezillie, B.; Bates, S.; Glaser, M.; Lemeilleur, F.; Leroy, C.

    1997-01-01

    Impurity concentrations in the initial silicon material are expected to play an important role for the radiation hardness of silicon detectors, during their irradiation and for their evolution with time after irradiation. This work reports on the experimental results obtained with detectors manufactured using various float-zone (FZ) and epitaxial-grown material. Preliminary results comparing the changes in leakage current and full depletion voltage of FZ and epitaxial detectors as a function of fluence and of time after 10 14 cm -2 proton irradiation are given. The measurement of charge collection efficiency for epitaxial detectors is also presented. (orig.)

  4. Cryogenic and radiation-hard asic for interfacing large format NIR/SWIR detector arrays

    Science.gov (United States)

    Gao, Peng; Dupont, Benoit; Dierickx, Bart; Müller, Eric; Verbruggen, Geert; Gielis, Stijn; Valvekens, Ramses

    2017-11-01

    For scientific and earth observation space missions, weight and power consumption is usually a critical factor. In order to obtain better vehicle integration, efficiency and controllability for large format NIR/SWIR detector arrays, a prototype ASIC is designed. It performs multiple detector array interfacing, power regulation and data acquisition operations inside the cryogenic chambers. Both operation commands and imaging data are communicated via the SpaceWire interface which will significantly reduce the number of wire goes in and out the cryogenic chamber. This "ASIC" prototype is realized in 0.18um CMOS technology and is designed for radiation hardness.

  5. Study of Radiation Hardness of Gd2SiO5 scintillator for Heavy Ion Beam

    CERN Document Server

    Kawade, K; Itow, Y; Masuda, K; Murakami, T; Sako,T; Suzuki, K; Suzuki, T; Taki, K

    2011-01-01

    Gd2SiO5 (GSO) scintillator has very excellent radiation resistance, a fast decay time and a large light yield. Because of these features, GSO scintillator is a suitable material for high radiation environment experiments such as those encountered at high energy accelerators. The radiation hardness of GSO has been measured with Carbon ion beams at the Heavy Ion Medical Accelerator in Chiba (HIMAC). During two nights of irradiation the GSO received a total radiation dose of 7 × 10$^5$ Gy and no decrease of light yield was observed. On the other hand an increase of light yield by 25% was observed. The increase is proportional to the total dose, increasing at a rate of 0.025%/Gy and saturating at around 1 kGy. Recovery to the initial light yield was also observed during the day between two nights of radiation exposure. The recovery was observed to have a slow exponential time constant of approximately 1.5 × 10$^4$ seconds together with a faster component. In case of the LHCf experiment, a very forward region ex...

  6. The radiation hardness of silica optical fiber used in the LED-fiber monitor of BLM and BESIII EMC

    International Nuclear Information System (INIS)

    Xue Zhen; Hu Tao; Fang Jian; Xu Zizong; Wang Xiaolian; Lü Junguang; Zhou Li; Cai Xiao; Yu Boxiang; Wang Zhigang; Sun Lijun; Sun Xilei; Zhang Aiwu

    2012-01-01

    LED-fiber system has been used to monitor BLM and BESIII EMC. A radiation hard silica optical fiber is essential for its stability and reliability. Three types of silica optical fibers, silicone-clad silica optical fiber with high OH - content (SeCS), silica-clad silica optical fiber with low OH - content (SCSL) and silica-clad silica opical fiber with high OH - content (SCSH) were studied. In the experiment, 12 groups of fiber samples were irradiated by 60 Co and 3 groups of fiber samples were irradiated by BEPCII background radiation. Radiation hardness: the radiation hardness of SCSH is best and meets the radiation hardness requirement for LED-fiber monitor of BLM and BESIII EMC. The transmission of SeCS and SCSH decreased to around 80% under the 60 Co-irradiation of 5 Gy and 10 Gy, respectively. The radiation hardness of SeCS is worst because of its silicone cladding. Recovery characteristics: 60 Co-irradiated by the same doses, there were both more annealable and more permanent color centers formed in SeCS than SCSL, and for the same kind of fibers, as long as the irradiated doses are under a certain amount (for example, less than 5 Gy for SeCS), the higher the doses, both the more annealable and the more permanent color centers are formed.

  7. Radiation-Hard Complementary Integrated Circuits Based on Semiconducting Single-Walled Carbon Nanotubes.

    Science.gov (United States)

    McMorrow, Julian J; Cress, Cory D; Gaviria Rojas, William A; Geier, Michael L; Marks, Tobin J; Hersam, Mark C

    2017-03-28

    Increasingly complex demonstrations of integrated circuit elements based on semiconducting single-walled carbon nanotubes (SWCNTs) mark the maturation of this technology for use in next-generation electronics. In particular, organic materials have recently been leveraged as dopant and encapsulation layers to enable stable SWCNT-based rail-to-rail, low-power complementary metal-oxide-semiconductor (CMOS) logic circuits. To explore the limits of this technology in extreme environments, here we study total ionizing dose (TID) effects in enhancement-mode SWCNT-CMOS inverters that employ organic doping and encapsulation layers. Details of the evolution of the device transport properties are revealed by in situ and in operando measurements, identifying n-type transistors as the more TID-sensitive component of the CMOS system with over an order of magnitude larger degradation of the static power dissipation. To further improve device stability, radiation-hardening approaches are explored, resulting in the observation that SWNCT-CMOS circuits are TID-hard under dynamic bias operation. Overall, this work reveals conditions under which SWCNTs can be employed for radiation-hard integrated circuits, thus presenting significant potential for next-generation satellite and space applications.

  8. Radiation hardness of silicon detectors manufactured on epitaxial material and FZ bulk enriched with oxygen, carbon, tin and platinum

    CERN Document Server

    Ruzin, A; Glaser, M; Lemeilleur, F; Talamonti, R; Watts, S; Zanet, A

    1999-01-01

    Recent results on the radiation hardness of silicon detectors fabricated on epitaxial and float zone bulk silicon enriched by various impurities, such as carbon, oxygen, tin and platinum are reported. A new methodology of measurements of electrical properties of the devices has been utilized in the experiment. It has been shown that in the case of irradiation by protons, oxygen enriched silicon has better radiation hardness than standard float zone silicon. The carbon enriched silicon detectors, on the other hand, exhibited significantly inferior radiation hardness compared to standard detectors. This study shows for the first time, a violation of the widely used normalization technique of the various particle irradiations by NIEL coefficients. The study has been carried out in the framework of the RD48 (ROSE) collaboration, which studies the radiation hardening of silicon detectors. (5 refs).

  9. Ridge regression for predicting elastic moduli and hardness of calcium aluminosilicate glasses

    Science.gov (United States)

    Deng, Yifan; Zeng, Huidan; Jiang, Yejia; Chen, Guorong; Chen, Jianding; Sun, Luyi

    2018-03-01

    It is of great significance to design glasses with satisfactory mechanical properties predictively through modeling. Among various modeling methods, data-driven modeling is such a reliable approach that can dramatically shorten research duration, cut research cost and accelerate the development of glass materials. In this work, the ridge regression (RR) analysis was used to construct regression models for predicting the compositional dependence of CaO-Al2O3-SiO2 glass elastic moduli (Shear, Bulk, and Young’s moduli) and hardness based on the ternary diagram of the compositions. The property prediction over a large glass composition space was accomplished with known experimental data of various compositions in the literature, and the simulated results are in good agreement with the measured ones. This regression model can serve as a facile and effective tool for studying the relationship between the compositions and the property, enabling high-efficient design of glasses to meet the requirements for specific elasticity and hardness.

  10. Evaluation of accelerated test parameters for CMOS IC total dose hardness prediction

    International Nuclear Information System (INIS)

    Sogoyan, A.V.; Nikiforov, A.Y.; Chumakov, A.I.

    1999-01-01

    The approach to accelerated test parameters evaluation is presented in order to predict CMOS IC total dose behavior in variable dose-rate environment. The technique is based on the analytical model of MOSFET parameters total dose degradation. The simple way to estimate model parameter is proposed using IC's input-output MOSFET radiation test results. (authors)

  11. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

  12. Radiation hardness tests of piezoelectric actuators with fast neutrons at liquid helium temperature

    Energy Technology Data Exchange (ETDEWEB)

    Fouaidy, M.; Martinet, G.; Hammoudi, N.; Chatelet, F.; Olivier, A.; Blivet, S.; Galet, F. [CNRS-IN2P3-IPN Orsay, Orsay (France)

    2007-07-01

    Piezoelectric actuators, which are integrated into the cold tuning system and used to compensate the small mechanical deformations of the cavity wall induced by Lorentz forces due to the high electromagnetic surface field, may be located in the radiation environment during particle accelerator operation. In order to provide for a reliable operation of the accelerator, the performance and life time of piezoelectric actuators ({approx}24.000 units for ILC) should not show any significant degradation for long periods (i.e. machine life duration: {approx}20 years), even when subjected to intense radiation (i.e. gamma rays and fast neutrons). An experimental program, aimed at investigating the effect of fast neutrons radiation on the characteristics of piezoelectric actuators at liquid helium temperature (i.e. T{approx}4.2 K), was proposed for the working package WPNo.8 devoted to tuners development in the frame of CARE project. A neutrons irradiation facility, already installed at the CERI cyclotron located at Orleans (France), was upgraded and adapted for actuators irradiations tests purpose. A deuterons beam (maximum energy and beam current: 25 MeV and 35{mu}A) collides with a thin (thickness: 3 mm) beryllium target producing a high neutrons flux with low gamma dose ({approx}20%): a neutrons fluence of more than 10{sup 14} n/cm{sup 2} is achieved in {approx}20 hours of exposure. A dedicated cryostat was developed at IPN Orsay and used previously for radiation hardness test of calibrated cryogenic thermometers and pressure transducers used in LHC superconducting magnets. This cryostat could be operated either with liquid helium or liquid argon. This irradiation facility was upgraded for allowing fast turn-over of experiments and a dedicated experimental set-up was designed, fabricated, installed at CERI and successfully operated for radiation hardness tests of several piezoelectric actuators at T{approx}4.2 K. This new apparatus allows on-line automatic measurements

  13. Radiation hardness tests of piezoelectric actuators with fast neutrons at liquid helium temperature

    International Nuclear Information System (INIS)

    Fouaidy, M.; Martinet, G.; Hammoudi, N.; Chatelet, F.; Olivier, A.; Blivet, S.; Galet, F.

    2007-01-01

    Piezoelectric actuators, which are integrated into the cold tuning system and used to compensate the small mechanical deformations of the cavity wall induced by Lorentz forces due to the high electromagnetic surface field, may be located in the radiation environment during particle accelerator operation. In order to provide for a reliable operation of the accelerator, the performance and life time of piezoelectric actuators (∼24.000 units for ILC) should not show any significant degradation for long periods (i.e. machine life duration: ∼20 years), even when subjected to intense radiation (i.e. gamma rays and fast neutrons). An experimental program, aimed at investigating the effect of fast neutrons radiation on the characteristics of piezoelectric actuators at liquid helium temperature (i.e. T∼4.2 K), was proposed for the working package WPNo.8 devoted to tuners development in the frame of CARE project. A neutrons irradiation facility, already installed at the CERI cyclotron located at Orleans (France), was upgraded and adapted for actuators irradiations tests purpose. A deuterons beam (maximum energy and beam current: 25 MeV and 35μA) collides with a thin (thickness: 3 mm) beryllium target producing a high neutrons flux with low gamma dose (∼20%): a neutrons fluence of more than 10 14 n/cm 2 is achieved in ∼20 hours of exposure. A dedicated cryostat was developed at IPN Orsay and used previously for radiation hardness test of calibrated cryogenic thermometers and pressure transducers used in LHC superconducting magnets. This cryostat could be operated either with liquid helium or liquid argon. This irradiation facility was upgraded for allowing fast turn-over of experiments and a dedicated experimental set-up was designed, fabricated, installed at CERI and successfully operated for radiation hardness tests of several piezoelectric actuators at T∼4.2 K. This new apparatus allows on-line automatic measurements of actuators characteristics and the

  14. Development of Radiation-hard Bandgap Reference and Temperature Sensor in CMOS 130 nm Technology

    CERN Document Server

    Kuczynska, Marika; Bugiel, Szymon; Firlej, Miroslaw; Fiutowski, Tomasz; Idzik, Marek; Michelis, Stefano; Moron, Jakub; Przyborowski, Dominik; Swientek, Krzysztof

    2015-01-01

    A stable reference voltage (or current) source is a standard component of today's microelectronics systems. In particle physics experiments such reference is needed in spite of harsh ionizing radiation conditions, i.e. doses exceeding 100 Mrads and fluences above 1e15 n/cm2. After such radiation load a bandgap reference using standard p-n junction of bipolar transistor does not work properly. Instead of using standard p-n junctions, two enclosed layout transistor (ELTMOS) structures are used to create radiation-hard diodes: the ELT bulk diode and the diode obtained using the ELTMOS as dynamic threshold transistor (DTMOS). In this paper we have described several sub-1V references based on ELTMOS bulk diode and DTMOS based diode, using CMOS 130 nm process. Voltage references the structures with additional PTAT (Proportional To Absolute Temperature) output for temperature measurements were also designed. We present and compare post-layout simulations of the developed bandgap references and temperature sensors, w...

  15. Radiation hard silicon microstrip detectors for use in ATLAS at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, Lars Gimmestad

    2005-07-01

    The Large Hadron Collider (LHC) at CERN (Geneva, Switzerland) will accelerate protons in colliding beams to a center of mass energy of 14 TeV at very high luminosities. The ATLAS detector is being built to explore the physics in this unprecedented energy range. Tracking of charged particles in high-energy physics (HEP) experiments requires a high spatial resolution and fast signal readout, all with as little material as possible. Silicon microstrip detectors meet these requirements well and have been chosen for the Semiconductor Tracker (SCT) which is part of the inner tracking system of ATLAS and has a total area of 61 m2. During the 10 years of operation at LHC, the total fluence received by the detectors is sufficiently large that they will suffer a severe degradation from radiation induced damage. The damage affects both the physics performance of the detectors as well as their operability and a great challenge has been to develop radiation hard detectors for this environment. An extensive irradiation programme has been carried out where detectors of various designs, including defect engineering by oxygen enriched silicon, have been irradiated to the expected fluence. A subsequent thermal annealing period is included to account for a realistic annual maintenance schedule at room temperature, during which the radiation induced defects alter the detector properties significantly. This thesis presents work that has been carried out in the Bergen ATLAS group with results both from the irradiation programme and from detector testing during the module production. (Author)

  16. Recent advancements in the development of radiation hard semiconductor detectors for S-LHC

    CERN Document Server

    Fretwurst, E; Al-Ajili, A A; Alfieri, G; Allport, P P; Artuso, M; Assouak, S; Avset, B S; Barabash, L; Barcz, A; Bates, R; Biagi, S F; Bilei, G M; Bisello, D; Blue, A; Blumenau, A; Boisvert, V; Bölla, G; Bondarenko, G B; Borchi, E; Borrello, L; Bortoletto, D; Boscardin, M; Bosisio, L; Bowcock, T J V; Brodbeck, T J; Broz, J; Bruzzi, M; Brzozowski, A; Buda, M; Buhmann, P; Buttar, C; Campabadal, F; Campbell, D; Candelori, A; Casse, G; Cavallini, A; Charron, S; Chilingarov, A G; Chren, D; Cindro, V; Collins, P; Coluccia, R; Contarato, D; Coutinho, J; Creanza, D; Cunningham, L; Dalla Betta, G F; Dawson, I; de Boer, Wim; De Palma, M; Demina, R; Dervan, P; Dittongo, S; Dolezal, Z; Dolgolenko, A; Eberlein, T; Eremin, V; Fall, C; Fasolo, F; Ferbel, T; Fizzotti, F; Fleta, C; Focardi, E; Forton, E; García, C; García-Navarro, J E; Gaubas, E; Genest, M H; Gill, K A; Giolo, K; Glaser, M; Gössling, C; Golovine, V; González-Sevilla, S; Gorelov,I; Goss, J; Gouldwell-Bates, A; Grégoire, G; Gregori, P; Grigoriev, E; Grillo, A A; Groza, A; Guskov, J; Haddad, L; Härkönen, J; Hauler, F; Hoeferkamp, M; Honniger, F; Horazdovsky, T; Horisberger, R P; Horn, M; Houdayer, A; Hourahine, B; Hughes, G; Ilyashenko, Yu S; Irmscher, K; Ivanov, A; Jarasiunas, K; Johansen, K M H; Jones, B K; Jones, R; Joram, C; Jungermann, L; Kalinina, E; Kaminski, P; Karpenko, A; Karpov, A; Kazlauskiene, V; Kazukauskas, V; Khivrich, V; Khomenkov, V P; Kierstead, J A; Klaiber Lodewigs, J M; Klingenberg, R; Kodys, P; Kohout, Z; Korjenevski, S; Koski, M; Kozlowski, R; Kozodaev, M; Kramberger, G; Krasel, O; Kuznetsov, A; Kwan, S; Lagomarsino, S; Lassila-Perini, K M; Lastovetsky, V F; Latino, G; Lazanu, I; Lazanu, S; Lebedev, A; Lebel, C; Leinonen, K; Leroy, C; Li, Z; Lindström, G; Linhart, V; Litovchenko, P G; Litovchenko, A P; Lo Giudice, A; Lozano, M; Luczynski, Z; Luukka, Panja; Macchiolo, A; Makarenko, L F; Mandic, I; Manfredotti, C; Manna, N; Martí i García, S; Marunko, S; Mathieson, K; Melone, J; Menichelli, D; Messineo, A; Metcalfe, J; Miglio, S; Mikuz, M; Miyamoto, J; Moll, M; Monakhov, E; Moscatelli, F; Naoumov, D; Nossarzhevska, E; Nysten, J; Olivero, P; O'Shea, V; Palviainen, T; Paolini, C; Parkes, C; Passeri, D; Pein, U; Pellegrini, G; Perera, L; Petasecca, M; Piemonte, C; Pignatel, G U; Pinho, N; Pintilie, I; Pintilie, L; Polivtsev, L; Polozov, P; Popa, A; Populea, J; Pospísil, S; Pozza, A; Radicci, V; Rafí, J M; Rando, R; Röder, R; Rohe, T; Ronchin, S; Rott, C; Roy, A; Ruzin, A; Sadrozinski, H F W; Sakalauskas, S; Scaringella, M; Schiavulli, L; Schnetzer, S; Schumm, B; Sciortino, S; Scorzoni, A; Segneri, G; Seidela, S; Seiden, A; Sellberg, G; Sellin, P J; Sentenac, D; Shipsey, I; Sícho, P; Sloan, T; Solar, M; Son, S; Sopko, B; Sopko, V; Spencer, N; Stahl, J; Stolze, D; Stone, R; Storasta, J; Strokan, N; Sudzius, M; Surma, B; Suvorov, A; Svensson, B G; Tipton, P; Tomasek, M; Tsvetkov, A; Tuominen, E; Tuovinen, E; Tuuva, T; Tylchin, M; Uebersee, H; Uher, J; Ullán, M; Vaitkus, J V; Velthuis, J; Verbitskaya, E; Vrba, V; Wagner, G; Wilhelm, I; Worm, S; Wright, V; Wunstorf, R; Yiuri, Y; Zabierowski, P; Zaluzhny, A; Zavrtanik, M; Zen, M; Zhukov, V; Zorzi, N

    2005-01-01

    The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 1016 hadrons/cm2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of this challenge. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has started in 2002 an R&D program for the development of detector technologies that will fulfill the requirements of the S-LHC. Different strategies are followed by RD50 to improve the radiation tolerance. These include the development of defect engineered silicon like Czochralski, epitaxial and oxygen-enriched silicon and of other semiconductor materials like SiC and GaN as well as extensive studies of the microscopic defects responsible for the degradation of irradiated sensors. Furthe...

  17. Radiation hard silicon microstrip detectors for use in ATLAS at CERN

    International Nuclear Information System (INIS)

    Johansen, Lars Gimmestad

    2005-06-01

    The Large Hadron Collider (LHC) at CERN (Geneva, Switzerland) will accelerate protons in colliding beams to a center of mass energy of 14 TeV at very high luminosities. The ATLAS detector is being built to explore the physics in this unprecedented energy range. Tracking of charged particles in high-energy physics (HEP) experiments requires a high spatial resolution and fast signal readout, all with as little material as possible. Silicon microstrip detectors meet these requirements well and have been chosen for the Semiconductor Tracker (SCT) which is part of the inner tracking system of ATLAS and has a total area of 61 m2. During the 10 years of operation at LHC, the total fluence received by the detectors is sufficiently large that they will suffer a severe degradation from radiation induced damage. The damage affects both the physics performance of the detectors as well as their operability and a great challenge has been to develop radiation hard detectors for this environment. An extensive irradiation programme has been carried out where detectors of various designs, including defect engineering by oxygen enriched silicon, have been irradiated to the expected fluence. A subsequent thermal annealing period is included to account for a realistic annual maintenance schedule at room temperature, during which the radiation induced defects alter the detector properties significantly. This thesis presents work that has been carried out in the Bergen ATLAS group with results both from the irradiation programme and from detector testing during the module production. (Author)

  18. Life evaluation of FR-CV cable on thermal-radiation combined aging by micro-hardness

    International Nuclear Information System (INIS)

    Sugiyama, Masahiko; Ogata, Akimasa; Nitta, Makoto; Tani, Tsuneo; Yagi, Toshiaki; Seguchi, Tadao.

    1996-01-01

    For the evaluation of cable life for the application to nuclear facilities, the accelerated test was conducted by the combination of radiation and thermal oxidation. The degradation of FR-CV cable by the aging was monitored by tensile test, micro-hardness test, and gel-fraction measurement. The micro-hardness increased with the progress of degradation and related well with decrease of ultimate elongation of the sheath material, and was also reflected by the loss of plasticizer. The micro-hardness technique has a possibility to detect the degradation of cable as a non-destructive detector. (author)

  19. Radiation hardness of CMOS monolithic active pixel sensors manufactured in a 0.18 μm CMOS process

    Energy Technology Data Exchange (ETDEWEB)

    Linnik, Benjamin [Goethe-Universitaet Frankfurt (Germany); Collaboration: CBM-MVD-Collaboration

    2015-07-01

    CMOS Monolithic Active Pixels Sensors (MAPS) are considered as the technology of choice for various vertex detectors in particle and heavy-ion physics including the STAR HFT, the upgrade of the ALICE ITS, the future ILC detectors and the CBM experiment at FAIR. To match the requirements of those detectors, their hardness to radiation is being improved, among others in a joined research activity of the Goethe University Frankfurt and the IPHC Strasbourg. It was assumed that combining an improved high resistivity (1-8 kΩcm) sensitive medium with the features of a 0.18 μm CMOS process, is suited to reach substantial improvements in terms of radiation hardness as compared to earlier sensor designs. This strategy was tested with a novel generation of sensor prototypes named MIMOSA-32 and MIMOSA-34. We show results on the radiation hardness of those sensors and discuss its impact on the design of future vertex detectors.

  20. Response surface and neural network based predictive models of cutting temperature in hard turning

    Directory of Open Access Journals (Sweden)

    Mozammel Mia

    2016-11-01

    Full Text Available The present study aimed to develop the predictive models of average tool-workpiece interface temperature in hard turning of AISI 1060 steels by coated carbide insert. The Response Surface Methodology (RSM and Artificial Neural Network (ANN were employed to predict the temperature in respect of cutting speed, feed rate and material hardness. The number and orientation of the experimental trials, conducted in both dry and high pressure coolant (HPC environments, were planned using full factorial design. The temperature was measured by using the tool-work thermocouple. In RSM model, two quadratic equations of temperature were derived from experimental data. The analysis of variance (ANOVA and mean absolute percentage error (MAPE were performed to suffice the adequacy of the models. In ANN model, 80% data were used to train and 20% data were employed for testing. Like RSM, herein, the error analysis was also conducted. The accuracy of the RSM and ANN model was found to be ⩾99%. The ANN models exhibit an error of ∼5% MAE for testing data. The regression coefficient was found to be greater than 99.9% for both dry and HPC. Both these models are acceptable, although the ANN model demonstrated a higher accuracy. These models, if employed, are expected to provide a better control of cutting temperature in turning of hardened steel.

  1. Effects of gamma radiation on hard dental tissues of albino rats: investigation by light microscopy.

    Science.gov (United States)

    El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; El-Zainy, Medhat

    2013-08-01

    The present work aims at studying the effect of gamma radiation on the hard dental tissues. Eighty adult male albino rats with weights of about 250 g were used. The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy whole-body gamma doses. The effects on hard dental tissue samples were investigated after 48 h in histological and ground sections using light microscopy. Areas of acid phosphatase activity were detected using tartrate-resistant acid phosphatase (TRAP) stains. Observation of histological sections revealed disturbance in predentin thickness and odontoblastic layer as the irradiation dose increased. In cementum, widened cementocytes lacunae were occasionally detected even with low irradiated doses. On the other hand, relatively homogenous enamel was detected with darkened areas in enamel surface at doses over than 0.5 Gy. TRAP-positive cells were detected on the surface of the dentin of irradiated groups as well as cementum surface. Minimal detectable changes were observed in ground sections.

  2. Forecasting noise and radiation hardness of CMOS front-end electronics beyond the 100 nm frontier

    International Nuclear Information System (INIS)

    Re, V.; Gaioni, L.; Manghisoni, M.; Ratti, L.; Traversi, G.

    2010-01-01

    The progress of industrial microelectronic technologies has already overtaken the 130 nm CMOS generation that is currently the focus of IC designers for new front-end chips in LHC upgrades and other detector applications. In a broader time span, sub-100 nm CMOS processes may become appealing for the design of very compact front-end systems with advanced integrated functionalities. This is especially true in the case of pixel detectors, both for monolithic devices (MAPS) and for hybrid implementations where a high resistivity sensor is connected to a CMOS readout chip. Technologies beyond the 100 nm frontier have peculiar features, such as the evolution of the device gate material to reduce tunneling currents through the thin dielectric. These new physical device parameters may impact on functional properties such as noise and radiation hardness. On the basis of experimental data relevant to commercial devices, this work studies potential advantages and challenges associated to the design of low-noise and rad-hard analog circuits in these aggressively scaled technologies.

  3. Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders

    CERN Multimedia

    Joram, C; Gregor, I; Dierlamm, A H; Wilson, F F; Sloan, T; Tuboltsev, Y V; Marone, M; Artuso, M; Cindro, V; Bruzzi, M; Bhardwaj, A; Bohm, J; Mikestikova, M; Walz, M; Breindl, M A; Ruzin, A; Marunko, S; Guskov, J; Haerkoenen, J J; Pospisil, S; Fadeyev, V; Makarenko, L; Kaminski, P; Zelazko, J; Pintilie, L; Radu, R; Nistor, S V; Ullan comes, M; Storasta, J V; Gaubas, E; Lacasta llacer, C; Kilminster, B J; Garutti, E; Buhmann, P; Khomenkov, V; Poehlsen, J A; Fernandez garcia, M; Buttar, C; Eklund, L M; Munoz sanchez, F J; Eremin, V; Aleev, A; Modi, B; Sicho, P; Gisen, A J; Nikolopoulos, K; Van beuzekom, M G; Kozlowski, R; Lozano fantoba, M; Leroy, C; Pernegger, H; Del burgo, R; Vila alvarez, I; Palomo pinto, F R; Lounis, A; Eremin, I; Fadeeva, N; Rogozhkin, S; Shivpuri, R K; Arsenovich, T; Ott, J; Abt, M; Loenker, J; Savic, N; Monaco, V; Visser, J; Lynn, D; Horazdovsky, T; Solar, M; Dervan, P J; Meng, L; Spencer, E N; Kazuchits, N; Brzozowski, A; Kozubal, M; Nistor, L C; Marti i garcia, S; Gomez camacho, J J; Fretwurst, E; Hoenniger, F; Schwandt, J; Hartmann, F; Marchiori, G; Maneuski, D; De capua, S; Williams, M R J; Mandic, I; Gadda, A; Preiss, J; Macchiolo, A; Nisius, R; Grinstein, S; Gonella, L; Wennloef, H L O; Slavicek, T; Masek, P; Casse, G; Flores, D; Tuuva, T; Jimenez ramos, M D C; Charron, S; Rubinskiy, I; Jansen, H; Eichhorn, T V; Matysek, M; Andersson-lindstroem, G; Donegani, E; Bomben, M; Oshea, V; Muenstermann, D; Holmkvist, C W; Oh, A; Lopez paz, I; Verbitskaya, E; Mitina, D; Grigoriev, E; Zaluzhnyy, A; Mikuz, M; Kramberger, G; Scaringella, M; Ranjeet, R; Jain, A; Luukka, P R; Tuominen, E M; Allport, P P; Cartiglia, N; Brigljevic, V; Kohout, Z; Quirion, D; Lauer, K; Collins, P; Gallrapp, C; Rohe, T V; Chauveau, J; Villani, E G; Fox, H; Parkes, C J; Nikitin, A; Spiegel, L G; Creanza, D M; Menichelli, D; Mcduff, H; Carna, M; Weers, M; Weigell, P; Bortoletto, D; Staiano, A; Bellan, R; Szumlak, T; Sopko, V; Pawlowski, M; Pintilie, I; Pellegrini, G; Rafi tatjer, J M; Moll, M; Eckstein, D; Klanner, R; Gomez, G; Gersabeck, M; Cobbledick, J L; Shepelev, A; Golubev, A; Apresyan, A; Lipton, R J; Borgia, A; Zavrtanik, M; Manna, N; Ranjan, K; Chhabra, S; Beyer, J; Korolkov, I; Heintz, U; Sadrozinski, H; Seiden, A; Surma, B; Esteban, S; Kazukauskas, V; Kalendra, V; Mekys, A; Nachman, B P; Tackmann, K; Steinbrueck, G; Pohlsen, T; Calderini, G; Svihra, P; Murray, D; Bolla, G; Zontar, D; Focardi, E; Seidel, S C; Winkler, A D; Altenheiner, S; Parzefall, U; Moser, H; Sopko, B; Buckland, M D; Vaitkus, J V; Ortlepp, T

    2002-01-01

    The requirements at the Large Hadron Collider (LHC) at CERN have pushed the present day silicon tracking detectors to the very edge of the current technology. Future very high luminosity colliders or a possible upgrade scenario of the LHC to a luminosity of 10$^{35}$ cm$^{-2}$s$^{-1}$ will require semiconductor detectors with substantially improved properties. Considering the expected total fluences of fast hadrons above 10$^{16}$ cm$^{-2}$ and a possible reduced bunch-crossing interval of $\\approx$10 ns, the detector must be ultra radiation hard, provide a fast and efficient charge collection and be as thin as possible.\\\\ We propose a research and development program to provide a detector technology, which is able to operate safely and efficiently in such an environment. Within this project we will optimize existing methods and evaluate new ways to engineer the silicon bulk material, the detector structure and the detector operational conditions. Furthermore, possibilities to use semiconductor materials othe...

  4. Development of radiation hard CMOS active pixel sensors for HL-LHC

    International Nuclear Information System (INIS)

    Pernegger, Heinz

    2016-01-01

    New pixel detectors, based on commercial high voltage and/or high resistivity full CMOS processes, hold promise as next-generation active pixel sensors for inner and intermediate layers of the upgraded ATLAS tracker. The use of commercial CMOS processes allow cost-effective detector construction and simpler hybridisation techniques. The paper gives an overview of the results obtained on AMS-produced CMOS sensors coupled to the ATLAS Pixel FE-I4 readout chips. The SOI (silicon-on-insulator) produced sensors by XFAB hold great promise as radiation hard SOI-CMOS sensors due to their combination of partially depleted SOI transistors reducing back-gate effects. The test results include pre-/post-irradiation comparison, measurements of charge collection regions as well as test beam results.

  5. A radiation hard dipole magnet coils using aluminum clad copper conductors

    International Nuclear Information System (INIS)

    Leonhardt, W.J.

    1989-01-01

    A C-type septum dipole magnet is located 600 mm downstream of the primary target in an external beam line of the AGS. Conventional use of fiber glass/epoxy electrical insulation for the magnet coils results in their failure after a relatively short running period, therefore a radiation hard insulation system is required. This is accomplished by replacing the existing copper conductor with a copper conductor having a thin aluminum skin which is anodized to provide the electrical insulation. Since the copper supports a current density of 59 A/mm 2 , no reduction in cross sectional area can be tolerated. Design considerations, manufacturing techniques, and operating experience of a prototype dipole is presented. 3 refs., 4 figs

  6. Radiation hardness tests of double-sided 3D strip sensors with passing-through columns

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Betta, Gian-Franco, E-mail: gianfranco.dallabetta@unitn.it [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); INFN TIFPA, Via Sommarive 14, I-38123 Trento (Italy); Betancourt, Christopher [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Boscardin, Maurizio; Giacomini, Gabriele [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive 18, I-38123 Trento (Italy); Jakobs, Karl; Kühn, Susanne [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Lecini, Besnik [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); Mendicino, Roberto [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); INFN TIFPA, Via Sommarive 14, I-38123 Trento (Italy); Mori, Riccardo; Parzefall, Ulrich [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Povoli, Marco [Dipartimento di Ingegneria Industriale, Università degli Studi di Trento, Via Sommarive 9, I-38123 Trento (Italy); Thomas, Maira [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Zorzi, Nicola [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive 18, I-38123 Trento (Italy)

    2014-11-21

    This paper deals with a radiation hardness study performed on double-sided 3D strip sensors with passing-through columns. Selected results from the characterization of the irradiated sensors with a beta source and a laser setup are reported and compared to pre-irradiation results and to TCAD simulations. The sensor performance in terms of signal efficiency is found to be in good agreement with that of other 3D sensors irradiated at the same fluences and tested under similar experimental conditions. - Highlights: • We report results from 3D silicon strip detectors irradiated up to HL-LHC fluences. • I–V curves, noise, charge collection measurements and laser scans are shown. • In all sensors, signals are distinguished from the noise already at low voltage. • Signal efficiency is in agreement with values expected from the electrode geometry. • Efficiency and spatial uniformity would benefit from higher operation voltages.

  7. Radiation hardness tests of double-sided 3D strip sensors with passing-through columns

    International Nuclear Information System (INIS)

    Dalla Betta, Gian-Franco; Betancourt, Christopher; Boscardin, Maurizio; Giacomini, Gabriele; Jakobs, Karl; Kühn, Susanne; Lecini, Besnik; Mendicino, Roberto; Mori, Riccardo; Parzefall, Ulrich; Povoli, Marco; Thomas, Maira; Zorzi, Nicola

    2014-01-01

    This paper deals with a radiation hardness study performed on double-sided 3D strip sensors with passing-through columns. Selected results from the characterization of the irradiated sensors with a beta source and a laser setup are reported and compared to pre-irradiation results and to TCAD simulations. The sensor performance in terms of signal efficiency is found to be in good agreement with that of other 3D sensors irradiated at the same fluences and tested under similar experimental conditions. - Highlights: • We report results from 3D silicon strip detectors irradiated up to HL-LHC fluences. • I–V curves, noise, charge collection measurements and laser scans are shown. • In all sensors, signals are distinguished from the noise already at low voltage. • Signal efficiency is in agreement with values expected from the electrode geometry. • Efficiency and spatial uniformity would benefit from higher operation voltages

  8. Development, optimisation and characterisation of a radiation hard mixed-signal readout chip for LHCb

    Energy Technology Data Exchange (ETDEWEB)

    Loechner, S.

    2006-07-26

    The Beetle chip is a radiation hard, 128 channel pipelined readout chip for silicon strip detectors. The front-end consists of a charge-sensitive preamplifier followed by a CR-RC pulse shaper. The analogue pipeline memory is implemented as a switched capacitor array with a maximum latency of 4us. The 128 analogue channels are multiplexed and transmitted off chip in 900ns via four current output drivers. Beside the pipelined readout path, the Beetle provides a fast discrimination of the front-end pulse. Within this doctoral thesis parts of the radiation hard Beetle readout chip for the LHCb experiment have been developed. The overall chip performances like noise, power consumption, input charge rates have been optimised as well as the elimination of failures so that the Beetle fulfils the requirements of the experiment. Furthermore the characterisation of the chip was a major part of this thesis. Beside the detailed measurement of the chip performance, several irradiation tests and an Single Event Upset (SEU) test were performed. A long-time measurement with a silicon strip detector was also part of this work as well as the development and test of a first mass production test setup. The Beetle chip showed no functional failure and only slight degradation in the analogue performance under irradiation of up to 130Mrad total dose. The Beetle chip fulfils all requirements of the vertex detector (VELO), the trigger tracker (TT) and the inner tracker (IT) and is ready for the start of LHCb end of 2007. (orig.)

  9. Development, optimisation and characterisation of a radiation hard mixed-signal readout chip for LHCb

    International Nuclear Information System (INIS)

    Loechner, S.

    2006-01-01

    The Beetle chip is a radiation hard, 128 channel pipelined readout chip for silicon strip detectors. The front-end consists of a charge-sensitive preamplifier followed by a CR-RC pulse shaper. The analogue pipeline memory is implemented as a switched capacitor array with a maximum latency of 4us. The 128 analogue channels are multiplexed and transmitted off chip in 900ns via four current output drivers. Beside the pipelined readout path, the Beetle provides a fast discrimination of the front-end pulse. Within this doctoral thesis parts of the radiation hard Beetle readout chip for the LHCb experiment have been developed. The overall chip performances like noise, power consumption, input charge rates have been optimised as well as the elimination of failures so that the Beetle fulfils the requirements of the experiment. Furthermore the characterisation of the chip was a major part of this thesis. Beside the detailed measurement of the chip performance, several irradiation tests and an Single Event Upset (SEU) test were performed. A long-time measurement with a silicon strip detector was also part of this work as well as the development and test of a first mass production test setup. The Beetle chip showed no functional failure and only slight degradation in the analogue performance under irradiation of up to 130Mrad total dose. The Beetle chip fulfils all requirements of the vertex detector (VELO), the trigger tracker (TT) and the inner tracker (IT) and is ready for the start of LHCb end of 2007. (orig.)

  10. A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing

    International Nuclear Information System (INIS)

    Camargo, Fábio de; Gonçalves, Josemary A.C.; Bueno, Carmen C.

    2017-01-01

    In this work, we report on the results obtained with rad-hard Standard Float Zone (STFZ) and Diffused Oxygenated Float Zone (DOFZ) silicon diodes in radiation processing dosimetry. The dosimetric probes were designed to operate in the direct current mode, as on-line radiation dosimeter. The irradiation of the samples was performed using a 60 Co source with a dose rate of almost 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. In this dose range it is observed a significant decrease in the photocurrent generated in both devices due to gamma radiation defects produced in their active volumes. To mitigate this effect, the samples were pre-irradiated with 60 Co gamma rays at 700 kGy. Despite of being less sensitive, these devices presented stable and reproducible current signals with a relative sensitivity decrease of about 19% within the whole range of dose studied. The dose-response curves of the pre-irradiated diodes showed quadratic behavior with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison of the FZ and DOFZ responses evidenced that the latter was slightly superior to the first. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications. (author)

  11. A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Fábio de [Amazônia Azul Tecnologias de Defesa S.A. (AMAZUL), São Paulo, SP (Brazil); Gonçalves, Josemary A.C.; Bueno, Carmen C., E-mail: dcamargo@gmail.com, E-mail: ccbueno@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

    2017-07-01

    In this work, we report on the results obtained with rad-hard Standard Float Zone (STFZ) and Diffused Oxygenated Float Zone (DOFZ) silicon diodes in radiation processing dosimetry. The dosimetric probes were designed to operate in the direct current mode, as on-line radiation dosimeter. The irradiation of the samples was performed using a {sup 60}Co source with a dose rate of almost 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. In this dose range it is observed a significant decrease in the photocurrent generated in both devices due to gamma radiation defects produced in their active volumes. To mitigate this effect, the samples were pre-irradiated with {sup 60}Co gamma rays at 700 kGy. Despite of being less sensitive, these devices presented stable and reproducible current signals with a relative sensitivity decrease of about 19% within the whole range of dose studied. The dose-response curves of the pre-irradiated diodes showed quadratic behavior with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison of the FZ and DOFZ responses evidenced that the latter was slightly superior to the first. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications. (author)

  12. Low-Dimensional Nanomaterials and Molecular Dielectrics for Radiation-Hard Electronics

    Science.gov (United States)

    McMorrow, Julian

    memory (SRAM) cells, an accomplishment that illustrates the technological relevance of this work by implementing a highly utilized component of modern day computing. Next, these SRAM devices demonstrate functionality as true random number generators (TRNGs), which are critical components in cryptography and encryption. The randomness of these SWCNT TRNGs is verified by a suite of statistical tests. This achievement has implications for securing data and communication in future solution-processed, large-area, flexible electronics. The unprecedented integration achieved by the underlying SWCNT doping and encapsulation motivates the study of this technology in a radiation environment. Doing so results in an understanding of the fundamental charge trapping mechanisms responsible for the radiation response in this system. The integrated nature of these devices enables, for the first time, the observation of system-level effects in a SWCNT integrated circuit technology. This technology is found to be total ionizing dose-hard, a promising result for the adoption of SWCNTs in future space-bound applications. Compared to SWCNTs, the field of MoS2 electronics is relatively nascent. As a result, studies of radiation effects in MoS2 devices focus on the fundamental mechanisms at play in the materials system. Here, we reveal the critical role of atmospheric adsorbates in the radiation effects of MoS2 transistors by measuring their response to vacuum ultraviolet radiation. These results highlight the importance of controlling the atmosphere of MoS2 devices during irradiation. Furthermore, we make recommendations for radiation-hard MoS2-based devices in the future as the technology continues to mature. One such recommendation is the incorporation of specialized dielectrics with proven radiation hardness. To this end, we address the materials integration challenge of incorporating SAND gate dielectrics on arbitrary substrates. We explore a novel approach for preparing metal substrates

  13. Hard-Wired Dopant Networks and the Prediction of High Transition Temperatures in Ceramic Superconductors

    International Nuclear Information System (INIS)

    Phillips, J.C.

    2010-01-01

    The review multiple successes of the discrete hard-wired dopant network model ZZIP, and comment on the equally numerous failures of continuum models, in describing and predicting the properties of ceramic superconductors. The prediction of transition temperatures can be regarded in several ways, either as an exacting test of theory, or as a tool for identifying theoretical rules for defining new homology models. Popular first principle methods for predicting transition temperatures in conventional crystalline superconductors have failed for cuprate HTSC, as have parameterized models based on CuO2 planes (with or without apical oxygen). Following a path suggested by Bayesian probability, it was found that the glassy, self-organized dopant network percolative model is so successful that it defines a new homology class appropriate to ceramic superconductors. The reasons for this success in an exponentially complex (non-polynomial complete, NPC) problem are discussed, and a critical comparison is made with previous polynomial (PC) theories. The predictions are successful for the superfamily of all ceramics, including new non-cuprates based on FeAs in place of CuO2.

  14. Time-resolved hard x-ray studies using third-generation synchrotron radiation sources (abstract)

    International Nuclear Information System (INIS)

    Mills, D.M.

    1992-01-01

    The third-generation, high-brilliance, synchrotron radiation sources currently under construction will usher in a new era of x-ray research in the physical, chemical, and biological sciences. One of the most exciting areas of experimentation will be the extension of static x-ray scattering and diffraction techniques to the study of transient or time-evolving systems. The high repetition rate, short-pulse duration, high-brilliance, variable spectral bandwidth, and large particle beam energies of these sources make them ideal for hard x-ray, time-resolved studies. The primary focus of this presentation will be on the novel instrumentation required for time-resolved studies such as optics which can increase the flux on the sample or disperse the x-ray beam, detectors and electronics for parallel data collection, and methods for altering the natural time structure of the radiation. This work is supported by the U.S. Department of Energy, BES-Materials Science, under Contract No. W-31-109-ENG-38

  15. Decision feedback equalization for radiation hard data link at 5 Gbps

    International Nuclear Information System (INIS)

    Wallängen, V.; Garcia-Sciveres, M.

    2017-01-01

    The increased particle collision rate following the upgrade of the Large Hadron Collider (LHC) to an increased luminosity requires an increased readout data speed, especially for the ATLAS pixel detector, located closest to the particle interaction point. For this reason, during the Phase-II upgrade of the ATLAS experiment the output data speed of the pixel front-end chips will be increased from 160 Mbps to 5 Gbps. The increased radiation levels will require a radiation hard data transmission link to be designed to carry this data from the pixel front-end to the off-detector system where it will undergo optical conversion. We propose a receiver utilizing the concept of Decision Feedback Equalization (DFE) to be used in this link, where the number of filter taps can be determined from simulations using S-parameter data from measurements of various customized cable prototypes under characterization as candidates to function as transmission medium between the on-chip data driver and the receiver of the link. A dedicated framework has been set up in Matlab to analyze the S-parameter characteristics for the various cable prototypes and investigate the possibilities for signal recovery and maintained signal integrity using DFE, as well as pre-emphasis and different encoding schemes. The simulation results indicate that DFE could be an excellent choice for expanding the system bandwidth to reach required data speeds with minimal signal distortion.

  16. Non-stoichiometry defects and radiation hardness of lead tungstate crystals PbWO sub 4

    CERN Document Server

    Devitsin, E G; Potashov, S Yu; Terkulov, A R; Nefedov, V A; Polyansky, E V; Zadneprovski, B I; Kjellberg, P; Korbel, V

    2002-01-01

    It has been stated many times that the formation of radiation infringements in PbWO sub 4 is to a big extent stipulated by the non-stoichiometry defects of the crystals, arising in the process of their growth and annealing. To refine the idea of characteristics of the non-stoichiometry defects and their effect on the radiation hardness of PbWO sub 4 , the current study is aimed at the melt composition infringements during its evaporation and at optical transmission of crystals obtained in these conditions after their irradiation ( sup 1 sup 3 sup 7 Cs source). In the optical transmission measurements along with traditional techniques a method 'in situ' was used, which provided the measurements in fixed points of the spectrum (380, 470 and 535 nm) directly in the process of the irradiation. X-ray phase and fluorescence analysis of condensation products of vapours over PbWO sub 4 melt has found PbWO sub 4 phase in their content as well as compounds rich in lead PbO, Pb sub 2 WO sub 5 with overall ratio Pb/W (3....

  17. Non-stoichiometry Defects and Radiation Hardness of Lead Tungstate Crystals PbWO4

    CERN Document Server

    Devitsin, E G; Kozlov, V A; Nefedov, L; Polyansky, E V; Potashov, S Yu; Terkulov, A R; Zadneprovski, B I

    2001-01-01

    It has been stated many times that the formation of radiation infringements in PbWO4 is to big extent stipulated by non-stoichiometry defects of the crystals, arising in the process of their growth and annealing. To refine the idea of characteristics of non-stoichiometry defects and their effect on the radiation hardness of PbWO4 the current study is aimed at the melt composition infringements during its evaporation and at optical transmission of crystals obtained in these conditions after their irradiation (137Cs source). In the optical transmission measurements along with traditional techniques a method "in situ" was used, which provided the measurements in fixed points of the spectrum (380, 470 and 535 nm) directly in the process of the irradiation. X-ray phase and fluorescence analysis of condensation products of vapours over PbWO4 melt has found PbWO4 phase in their content as well as compounds rich in lead, PbO, Pb2WO5, with overall ratio Pb/W = 3.2. Correspondingly the lack of lead and variations in th...

  18. First tests of a novel radiation hard CMOS sensor process for Depleted Monolithic Active Pixel Sensors

    Science.gov (United States)

    Pernegger, H.; Bates, R.; Buttar, C.; Dalla, M.; van Hoorne, J. W.; Kugathasan, T.; Maneuski, D.; Musa, L.; Riedler, P.; Riegel, C.; Sbarra, C.; Schaefer, D.; Schioppa, E. J.; Snoeys, W.

    2017-06-01

    The upgrade of the ATLAS [1] tracking detector for the High-Luminosity Large Hadron Collider (LHC) at CERN requires novel radiation hard silicon sensor technologies. Significant effort has been put into the development of monolithic CMOS sensors but it has been a challenge to combine a low capacitance of the sensing node with full depletion of the sensitive layer. Low capacitance brings low analog power. Depletion of the sensitive layer causes the signal charge to be collected by drift sufficiently fast to separate hits from consecutive bunch crossings (25 ns at the LHC) and to avoid losing the charge by trapping. This paper focuses on the characterization of charge collection properties and detection efficiency of prototype sensors originally designed in the framework of the ALICE Inner Tracking System (ITS) upgrade [2]. The prototypes are fabricated both in the standard TowerJazz 180nm CMOS imager process [3] and in an innovative modification of this process developed in collaboration with the foundry, aimed to fully deplete the sensitive epitaxial layer and enhance the tolerance to non-ionizing energy loss. Sensors fabricated in standard and modified process variants were characterized using radioactive sources, focused X-ray beam and test beams before and after irradiation. Contrary to sensors manufactured in the standard process, sensors from the modified process remain fully functional even after a dose of 1015neq/cm2, which is the the expected NIEL radiation fluence for the outer pixel layers in the future ATLAS Inner Tracker (ITk) [4].

  19. Radiation hardness and charge collection efficiency of lithium irradiated thin silicon diodes

    CERN Document Server

    Boscardin, Maurizio; Bruzzi, Mara; Candelori, Andrea; Focardi, Ettore; Khomenkov, Volodymyr P; Piemonte, Claudio; Ronchin, S; Tosi, C; Zorzi, N

    2005-01-01

    Due to their low depletion voltage, even after high particle fluences, improved tracking precision and momentum resolution, and reduced material budget, thin substrates are one of the possible choices to provide radiation hard detectors for future high energy physics experiments. In the framework of the CERN RD50 Collaboration, we have developed PIN diode detectors on membranes obtained by locally thinning the silicon substrate by means of TMAH etching from the wafer backside. Diodes of different shapes and sizes have been fabricated on 50- mu m and 100- mu m thick membranes and tested, showing a low leakage current (of 300 nA/cm/sup 3/) and a very low depletion voltage (in the order of 1 V for the 50 mu m membrane) before irradiation. Radiation damage tests have been performed with 58 MeV lithium (Li) ions up to the fluence of 10/sup 14/ Li/cm/sup 2/ in order to determine the depletion voltage and leakage current density increase after irradiation. Charge collection efficiency tests carried out with a beta /...

  20. Radiation Hardness tests with neutron flux on different Silicon photomultiplier devices

    Science.gov (United States)

    Cattaneo, P. W.; Cervi, T.; Menegolli, A.; Oddone, M.; Prata, M.; Prata, M. C.; Rossella, M.

    2017-07-01

    Radiation hardness is an important requirement for solid state readout devices operating in high radiation environments common in particle physics experiments. The MEG II experiment, at PSI, Switzerland, investigates the forbidden decay μ+ → e+ γ. Exploiting the most intense muon beam of the world. A significant flux of non-thermal neutrons (kinetic energy Ek>= 0.5 MeV) is present in the experimental hall produced along the beam-line and in the hall itself. We present the effects of neutron fluxes comparable to the MEG II expected doses on several Silicon Photomultiplier (SiPMs). The tested models are: AdvanSiD ASD-NUV3S-P50 (used in MEG II experiment), AdvanSiD ASD-NUV3S-P40, AdvanSiD ASD-RGB3S-P40, Hamamatsu and Excelitas C30742-33-050-X. The neutron source is the thermal Sub-critical Multiplication complex (SM1) moderated with water, located at the University of Pavia (Italy). We report the change of SiPMs most important electric parameters: dark current, dark pulse frequency, gain, direct bias resistance, as a function of the integrated neutron fluency.

  1. Development of cryogenic Si detectors by CERN RD39 Collaboration for ultra radiation hardness in SLHC environment

    CERN Document Server

    Li, Z; Anbinderis, P; Anbinderis, T; D’Ambrosio, N; de Boer, Wim; Borchi, E; Borer, K; Bruzzi, M; Buontempo, S; Chen, W; Cindro, V; Dierlamm, A; Eremin, V; Gaubas, E; Gorbatenko, V; Grigoriev, E; Hauler, F; Heijne, Erik H M; Heising, S; Hempel, O; Herzog, R; Härkönen, J; Ilyashenko, I; Janos, S; Jungermann, L; Kalesinskas, V; Kapturauskas, J; Laiho, R; Luukka, P; Mandic, I; De Masi, R; Menichelli, D; Mikuz, M; Militaru, O; Niinikosky, T O; O’Shea, V; Pagano, S; Paul, S; Piotrzkowski, K; Pretzl, K; Rato-Mendes, P; Rouby, X; Ruggiero, G; Smith, K; Sonderegger, P; Sousa, P; Tuominen, E; Tuovinen, E; Verbitskaya, E; Vaitkus, J; Wobst, E; Zavrtanik, M

    2007-01-01

    There are two key approaches in our CERN RD 39 Collaboration efforts to obtain ultra-radiation-hard Si detectors: (1) use of the charge/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range (150 K), and (2) freezing out of the trapping centers that affects the CCE at cryogenic temperatures lower than that of the liquid nitrogen (LN2) temperature. In our first approach, we have developed the advanced radiation hard detectors using charge or current injection, the current injected diodes (CID). In a CID, the electric field is controlled by injected current, which is limited by the space charge, yielding a nearly uniform electric field in the detector, independent of the radiation fluence. In our second approach, we have developed models of radiation-induced trapping levels and the physics of their freezing out at cryogenic temperatures.

  2. Evaluation of erbium:YAG and holmium:YAG laser radiation and dental hard tissue

    Science.gov (United States)

    Attrill, David Cameron

    Lasers have become increasingly established in medicine as effective alternatives or adjuncts to conventional techniques. In dentistry, several clinical laser systems have been developed and marketed, but their applications have been limited to soft tissue surgery. To date, no laser has been capable of effectively cutting or modifying the highly mineralised dental tissues of enamel and dentine. The aim of this study was to evaluate two new laser systems for use in dentistry through a series of in vitro experiments. Both generic erbium and holmium lasers have theoretically superior operating characteristics over currently established lasers for applications with dental hard tissues. The two lasers investigated in this study were pulsed Er:YAG (lambda=2.94) a.m. and Cr-Tm-Ho:YAG (lambda=2.1mu.m). Both operated with a macropulse duration of approximately 200lambdas, at pulse repetition rates of 2-8Hz and mean pulse energies up to 230mJ. Radiation was focused using CaF[2] lenses (f=50-120mm). The lasers could be operated with or without the addition of a surface water film at the interaction site. Tissue removal efficiency was expressed as a latent heat of ablation (LHA, kJ/cm[3]) using a modification of the technique described by Charlton et al. (1990). The mean LHA's for the Er:YAG laser were 6.24kJ/cm[3] and 22.99kJ/cm[3] with dentine and enamel respectively without water, and 10.07kJ/cm[3] and 18.73kJ/cm[3] for dentine and enamel with water. The Cr-Tm-Ho:YAG laser was unable to effectively remove enamel at the fluences and pulse energies available; the mean LHA's for the Cr-Tm- Ho:YAG laser with dentine were 82.79kJ/cm3 and 57.57kJ/cm3 with and without water respectively. The Cr-Tm-Ho;YAG was approximately 8-9 times less efficient for tissue removal than the Er:YAG system. Er:YAG tissue removal with water was characterised by clean "surgical" cuts, comparable in histological appearance to those obtained using conventional instrumentation. Some thermal disruption

  3. Single-Event Gate Rupture in Power MOSFETs: A New Radiation Hardness Assurance Approach

    Science.gov (United States)

    Lauenstein, Jean-Marie

    2011-01-01

    Almost every space mission uses vertical power metal-semiconductor-oxide field-effect transistors (MOSFETs) in its power-supply circuitry. These devices can fail catastrophically due to single-event gate rupture (SEGR) when exposed to energetic heavy ions. To reduce SEGR failure risk, the off-state operating voltages of the devices are derated based upon radiation tests at heavy-ion accelerator facilities. Testing is very expensive. Even so, data from these tests provide only a limited guide to on-orbit performance. In this work, a device simulation-based method is developed to measure the response to strikes from heavy ions unavailable at accelerator facilities but posing potential risk on orbit. This work is the first to show that the present derating factor, which was established from non-radiation reliability concerns, is appropriate to reduce on-orbit SEGR failure risk when applied to data acquired from ions with appropriate penetration range. A second important outcome of this study is the demonstration of the capability and usefulness of this simulation technique for augmenting SEGR data from accelerator beam facilities. The mechanisms of SEGR are two-fold: the gate oxide is weakened by the passage of the ion through it, and the charge ionized along the ion track in the silicon transiently increases the oxide electric field. Most hardness assurance methodologies consider the latter mechanism only. This work demonstrates through experiment and simulation that the gate oxide response should not be neglected. In addition, the premise that the temporary weakening of the oxide due to the ion interaction with it, as opposed to due to the transient oxide field generated from within the silicon, is validated. Based upon these findings, a new approach to radiation hardness assurance for SEGR in power MOSFETs is defined to reduce SEGR risk in space flight projects. Finally, the potential impact of accumulated dose over the course of a space mission on SEGR

  4. Numerical simulation of continuous cooling of a low alloy steel to predict microstructure and hardness

    International Nuclear Information System (INIS)

    Kakhki, M Eshraghi; Kermanpur, A; Golozar, M A

    2009-01-01

    In this work, a numerical model was developed to simulate the continuous cooling of a low alloy steel. In order to simulate the kinetics of diffusional phase transformations, the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation and additivity rule were employed, while a new model was applied for martensitic transformation. In addition, a novel approach was applied for computing the actual phase fractions in the multiphase steel. Effects of latent heat release during phase transformations, temperature and phase fractions on the variation of thermo-physical properties were considered. The developed numerical model was applied to simulate the cooling process during the Jominy end quench test as well as the quenching of a steel gear in water and oil. In this respect, precise models were used to simulate the complex boundary conditions in the Jominy test and a stainless steel probe was used for determining the heat transfer coefficients of quenching media by an inverse method. The present model was validated against cooling curve measurements, metallographic analysis and hardness tests. Good agreement was found between the experimental and simulation results. This model is able to simulate the continuous cooling and kinetics of phase transformation and to predict the final distribution of microstructures and hardness in low alloy steels

  5. Radiation-hard ASICS for sLHC optical data transmission

    International Nuclear Information System (INIS)

    Gan, K.K.

    2009-01-01

    High-speed data transmission in a high radiation environment poses an immense challenge in the detector design. We investigate the feasibility of using optical links for the silicon trackers of the ATLAS experiment for the planned upgrade of the LHC. The planned upgrade with ten times higher collision rate will produce a similar increase in the radiation. One possibility for the optical transmission is to use VCSEL arrays operating at 850 nm to transmit optical signals while using PIN arrays to convert the optical signals into electrical signals. We have designed a prototype chip containing building blocks for future SLHC optical links using a 130 nm CMOS 8RF process. The chip contains four main blocks; a VCSEL driver optimized for operation at 640 Mb/s, a VCSEL driver optimized for 3.2 Gb/s, a PIN receiver with a clock/data recovery circuit for operation at 40, 160, and 320 Mb/s, and two clock multipliers designed to operate at 640 Mb/s. The clock multiplier is designed to produce the high speed clock to serialize the data for transmission. All circuitry was designed following test results and guidelines from CERN on radiation tolerant design for the process. We have irradiated the chips with 24 GeV protons at CERN. For the VDC, the duty cycle of the output signal and the current consumption of the LVDS receiver remained constant during the irradiation. However, we observed significant decreases in the current consumption of the VCSEL driver circuit and the output drive current. This indicated that the think oxide layout used in the VCSEL driver portion of the chip might not be as radiation-hard and the circuit had been redesigned to minimize this sensitivity. For the PIN receiver, we found that the radiation produced no significant degradation, including the single event upset rate. The upset rate decreased with larger PIN current and was higher for a chip coupled to a PIN diode as expected. For the clock multipliers, we observed that the clocks of some chips

  6. Comparison of first quadrant yield loci for Ti--6Al--4V with those predicted by Knoop hardness measurements

    International Nuclear Information System (INIS)

    Amateau, M.F.; Hanna, W.D.

    1975-01-01

    Knoop hardness impressions were used to construct biaxial yield loci in Ti--6A l--4V for a variety of textures. These results were compared with partial yield loci in the first quadrant, determined from flow stress measurements at three stress ratios. In each case, the Knoop hardness technique was not sufficiently sensitive to predict the shape of the yield locus, the largest discrepancy occurring for the most anisotropic sample. (U.S.)

  7. Applications of Robust, Radiation Hard AlGaN Optoelectronic Devices in Space Exploration and High Energy Density Physics

    Energy Technology Data Exchange (ETDEWEB)

    Sun, K.

    2011-05-04

    This slide show presents: space exploration applications; high energy density physics applications; UV LED and photodiode radiation hardness; UV LED and photodiode space qualification; UV LED AC charge management; and UV LED satellite payload instruments. A UV LED satellite will be launched 2nd half 2012.

  8. Improvement of optical properties and radiation hardness of NaBi(WO sub 4) sub 2 Cherenkov crystals

    CERN Document Server

    Zadneprovski, B I; Polyansky, E V; Devitsin, E G; Kozlov, V A; Potashov, S Yu; Terkulov, A R

    2002-01-01

    On the basis of the data on melt evaporation while growing NaBi(WO sub 4) sub 2 Cherenkov crystals, the formation of nonstoichiometry and most probable types of dot defects of the crystals have been considered. The influence of melt nonstoichiometry and doping with Sc on optical transmission and radiation hardness of the crystals has been experimentally investigated. The surplus of WO sub 3 has been established to increase optical transmission and radiation hardness and lack of Bi sub 2 O sub 3 in the melt to reduce radiation hardness. Sc doping is shifting the absorption edge to UV region by 30-35 nm and is increasing radiation hardness of the crystals about three-fold. Analytical estimations give the increase of the number of Cherenkov photons by a factor of 1.3, which leads to an improvement of the energy resolution of a calorimeter based on NaBi(WO sub 4) sub 2 :Sc crystals compared with undoped NaBi(WO sub 4) sub 2 of approximately 15%.

  9. Hardness prediction for the repair welding of 2.25Cr-1Mo pressure vessels

    International Nuclear Information System (INIS)

    Oddy, A.S.; Chandel, R.S.

    1991-01-01

    Reactor vessels used for the hydrotreating of heavy oils and tar sand bitumen are frequently made of 2.25Cr-1Mo steel in thicknesses of 150 to 300 nm. Defects developed during installation or service are often repaired by welding. For practical reasons, postweld heat treatment of the repair welds is undesirable. This has led to continued effort to develop weld repair techniques that do not involve postweld heat treatment. Recently a six-layer automatic gas tungsten arc welding (GTAW) technique has been proposed for the repair welding of nuclear reactor vessels made of SA508 Class 2 Steel. In this technique, the second and third passes refine the microstructure of the first pass, and the last three passes temper the first pass. Alberry has developed a set of empirical rules predicting the hardness after each pass in multipass welds made in SA508 Class 2 Steels. This algorithm has been used to predict the number of layers required to achieve desired hardness. A transformation and tempering algorithm for 2.25Cr-1Mo, similar to that of the above steel, is presented. The tempering algorithm of Alberry suffers from several minor problems and can be improved. A mathematically correct method for the calculation of the tempering occurring in an anisothermal cycle is demonstrated. In addition, the rules used to relate the softening that occurs during temperature are heuristic. Separate rules are proposed for the kinetics of softening depending on the peak temperature. A re-examination of those rules reveals that they can be recast in the form of a single rule for the material examined. Reassessing the basic data presented by Alberry leads to a single softening rule with better theoretical justification

  10. Investigation of DEPFET as vertex detector at ILC. Intrinsic properties, radiation hardness and alternative readout schemes

    International Nuclear Information System (INIS)

    Rummel, Stefan

    2009-01-01

    The International Linear Collider (ILC) is supposed to be the next generation lepton collider. The detectors at ILC are intended to be precision instruments improving the performance in impact parameter (IP), momentum and energy resolution significantly compared to previous detectors at lepton colliders. To achieve this goal it is necessary to develop new detector technologies or pushing existing technologies to their technological edges. Regarding the Vertex detector (VTX) this implies challenges in resolution, material budget, power consumption and readout speed. A promising technology for the Vertex detector is the Depleted Field Effect Transistor (DEPFET). The DEPFET is a semiconductor device with in-pixel ampli cation integrated on a fully depleted bulk. This allows building detectors with intrinsically high SNR due to the large sensitive volume and the small input capacitance at the rst ampli er. To reach the ambitious performance goals it is important to understand its various features: clear performance, internal amplification, noise and radiation hardness. The intrinsic noise is analyzed, showing that the contribution of the DEPFET is below 50 e - at the required speed. Moreover it is possible to show that the internal ampli cation could be further improved to more than 1nA/e - using the standard DEPFET technology. The clear performance is investigated on matrix level utilizing a dedicated setup for single pixel testing which allows direct insight into the DEPFET operation, without the complexity of the full readout system. It is possible to show that a full clear could be achieved with a voltage pulse of 10 V. Furthermore a novel clear concept - the capacitive coupled clear gate - is demonstrated. The radiation hardness is studied with respect to the system performance utilizing various irradiations with ionizing and non ionizing particles. The impact on the bulk as well as the interface damage is investigated. Up to now the readout is performed with

  11. Investigation of DEPFET as vertex detector at ILC. Intrinsic properties, radiation hardness and alternative readout schemes

    Energy Technology Data Exchange (ETDEWEB)

    Rummel, Stefan

    2009-07-20

    The International Linear Collider (ILC) is supposed to be the next generation lepton collider. The detectors at ILC are intended to be precision instruments improving the performance in impact parameter (IP), momentum and energy resolution significantly compared to previous detectors at lepton colliders. To achieve this goal it is necessary to develop new detector technologies or pushing existing technologies to their technological edges. Regarding the Vertex detector (VTX) this implies challenges in resolution, material budget, power consumption and readout speed. A promising technology for the Vertex detector is the Depleted Field Effect Transistor (DEPFET). The DEPFET is a semiconductor device with in-pixel ampli cation integrated on a fully depleted bulk. This allows building detectors with intrinsically high SNR due to the large sensitive volume and the small input capacitance at the rst ampli er. To reach the ambitious performance goals it is important to understand its various features: clear performance, internal amplification, noise and radiation hardness. The intrinsic noise is analyzed, showing that the contribution of the DEPFET is below 50 e{sup -} at the required speed. Moreover it is possible to show that the internal ampli cation could be further improved to more than 1nA/e{sup -} using the standard DEPFET technology. The clear performance is investigated on matrix level utilizing a dedicated setup for single pixel testing which allows direct insight into the DEPFET operation, without the complexity of the full readout system. It is possible to show that a full clear could be achieved with a voltage pulse of 10 V. Furthermore a novel clear concept - the capacitive coupled clear gate - is demonstrated. The radiation hardness is studied with respect to the system performance utilizing various irradiations with ionizing and non ionizing particles. The impact on the bulk as well as the interface damage is investigated. Up to now the readout is performed

  12. First tests of a novel radiation hard CMOS sensor process for Depleted Monolithic Active Pixel Sensors

    International Nuclear Information System (INIS)

    Pernegger, H.; Hoorne, J.W. van; Kugathasan, T.; Musa, L.; Riedler, P.; Riegel, C.; Schaefer, D.; Schioppa, E.J.; Snoeys, W.; Bates, R.; Buttar, C.; Maneuski, D.; Dalla, M.; Sbarra, C.

    2017-01-01

    The upgrade of the ATLAS [1] tracking detector for the High-Luminosity Large Hadron Collider (LHC) at CERN requires novel radiation hard silicon sensor technologies. Significant effort has been put into the development of monolithic CMOS sensors but it has been a challenge to combine a low capacitance of the sensing node with full depletion of the sensitive layer. Low capacitance brings low analog power. Depletion of the sensitive layer causes the signal charge to be collected by drift sufficiently fast to separate hits from consecutive bunch crossings (25 ns at the LHC) and to avoid losing the charge by trapping. This paper focuses on the characterization of charge collection properties and detection efficiency of prototype sensors originally designed in the framework of the ALICE Inner Tracking System (ITS) upgrade [2]. The prototypes are fabricated both in the standard TowerJazz 180nm CMOS imager process [3] and in an innovative modification of this process developed in collaboration with the foundry, aimed to fully deplete the sensitive epitaxial layer and enhance the tolerance to non-ionizing energy loss. Sensors fabricated in standard and modified process variants were characterized using radioactive sources, focused X-ray beam and test beams before and after irradiation. Contrary to sensors manufactured in the standard process, sensors from the modified process remain fully functional even after a dose of 10"1"5 n _e_q/cm"2, which is the the expected NIEL radiation fluence for the outer pixel layers in the future ATLAS Inner Tracker (ITk) [4].

  13. Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade

    International Nuclear Information System (INIS)

    Gan, K.K.; Buchholz, P.; Kagan, H.P.; Kass, R.D.; Moore, J.R.; Smith, D.S.; Wiese, A.; Ziolkowskic, M.

    2011-01-01

    We have designed two ASICs for possible applications in the optical links of a new layer of the pixel detector to be install inside the ATLAS Pixel detector for the first phase of the LHC luminosity upgrade. The ASICs include a high-speed driver for a VCSEL and a receiver/decoder to decode the signal received at a PIN diode to extract the data and clock. Both ASICs contain 4 channels for operation with a VCSEL or PIN array. The ASICs were designed using a 130 nm CMOS process to enhance the radiation-hardness. We have characterized the fabricated ASICs and the performance of the ASICs is satisfactory. The receiver/decoder properly decodes the bi-phase marked input stream with low PIN current and the driver can operate a VCSEL up to ∼5 Gb/s. The added functionalities are also successful, including redundancy to bypass a broken VCSEL or PIN channel, individual control of VCSEL current, and power-on reset circuit to set all VCSEL currents to a nominal value.

  14. Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade

    International Nuclear Information System (INIS)

    Gan, K K; Kagan, H P; Kass, R D; Moore, J R; Smith, D S; Buchholz, P; Wiese, A; Ziolkowskic, M

    2010-01-01

    We have designed two ASICs for possible applications in the optical links of a new layer of the pixel detector to be install inside the ATLAS Pixel detector for the first phase of the LHC luminosity upgrade. The ASICs include a high-speed driver for the VCSEL and a receiver/decoder to decode the signal received at the PIN diode to extract the data and clock. Both ASICs contain 4 channels for operation with a VCSEL or PIN array. The ASICs were designed using a 130 nm CMOS process to enhance the radiation-hardness. We have characterized the fabricated ASICs and the performance of the ASICs is satisfactory. The receiver/decoder can properly decode the bi-phase marked input stream with low PIN current and the driver can operate a VCSEL up to ∼ 5 Gb/s. The added functionalities are also successful, including redundancy to bypass a broken VCSEL or PIN channel, individual control of VCSEL current, and power-on reset circuit to set all VCSEL currents to a nominal value. The ASICs were irradiated to a dose of 46 Mrad with 24 GeV/c protons. The observed modest degradation is acceptable and the single event upset rate is negligible.

  15. Radiation-hard ASICs for optical data transmission in the first phase of the LHC upgrade

    CERN Document Server

    Gan, K K; Kagan, H P; Kass, R D; Moore, J R; Smith, D S; Wiese, A; Ziolkowskic, M; 10.1088/1748-0221/5/12/C12006

    2010-01-01

    We have designed two ASICs for possible applications in the optical links of a new layer of the pixel detector to be install inside the ATLAS Pixel detector for the first phase of the LHC luminosity upgrade. The ASICs include a high-speed driver for the VCSEL and a receiver/decoder to decode the signal received at the PIN diode to extract the data and clock. Both ASICs contain 4 channels for operation with a VCSEL or PIN array. The ASICs were designed using a 130 nm CMOS process to enhance the radiation-hardness. We have characterized the fabricated ASICs and the performance of the ASICs is satisfactory. The receiver/decoder can properly decode the bi-phase marked input stream with low PIN current and the driver can operate a VCSEL up to ~ 5 Gb/s. The added functionalities are also successful, including redundancy to bypass a broken VCSEL or PIN channel, individual control of VCSEL current, and power-on reset circuit to set all VCSEL currents to a nominal value. The ASICs were irradiated to a dose of 46 Mrad ...

  16. A study on image quality and exposure dose of hard radiation radiography of the chest

    International Nuclear Information System (INIS)

    Hayashi, Taro; Ishida, Yuji; Maeda, Mika; Sakurai, Tatsuya; Kim, Chung Woon; Hwang, Jong Sun

    1991-01-01

    Experiment was conducted on the image quality and exposure dose following replacement of CaWO 4 system screen BH - III and BX - III which have so far been used for high - voltage hard - radiation quality radiography, with rare earth system screen KO750, combined with high contrast film SRH, while additional filter was altered, Cu 0.8 mm + Al 1.4 mm(HVL : AI 8.8 mm), Cu 1.3 mm + AI 1.0mm(HVL: AI 10.6mm) and Cu 1.8mm + AI 1.5mm(HVL: AI 11.4mm). AS a result, visual evaluation did not detect extreme changes in image quality under the respective condition (HVL : Al 8.8 mm ∼ AI 11.4 mm). It was noted, however, that surface exposure dose declined with an increase in the thickness of the additional filter, as it was 18.9 μGy at HVL Al 8.8 mm, 17.5 μGy at Al 10.6 mm and 15.7 μGy at Al 11.4 mm. Considering the limited rating of X-ray equipment and wear of machinery, however, the range of Cu 1.3 mm ∼ l.8 mm + AI 1.0 mm ∼ 1.5 mm(1/16 VL ∼ 1/32 VL) seemed to be a limit

  17. Development and characterisation of a radiation hard readout chip for the LHCb experiment

    CERN Document Server

    Baumeister, Daniel; Stachel, Johanna

    2003-01-01

    Within this doctoral thesis parts of the radiation hard readout chip Beetle have been developed and characterised, before and after irradiation. The design work included the analogue memory with the corresponding readout amplifier as well as components of the digital control circuitry. An interface compatible with the I2C-standard and the control logic for event readout have been implemented. A scheme has been developed which ensures the robustness of the Beetle chip against Single-Event Upset (SEU). This includes the consistent use of triple-redundant memory devices together with a self-triggered correction in parts of the circuit. The Beetle ASIC is a 128 channel pipelined readout chip for silicon strip detectors. The front-end consists of a charge-sensitive preamplifier and a CR-RC pulse shaper. It features an equivalent noise charge of ENC = 497 e− +48.3 e−/pF·Cin. The analogue memory is a switched capacitor array, which provides a latency of max. 4 µs. The 128 channels are transmitted off chip in 9...

  18. Towards radiation hard converter material for SiC-based fast neutron detectors

    Science.gov (United States)

    Tripathi, S.; Upadhyay, C.; Nagaraj, C. P.; Venkatesan, A.; Devan, K.

    2018-05-01

    In the present work, Geant4 Monte-Carlo simulations have been carried out to study the neutron detection efficiency of the various neutron to other charge particle (recoil proton) converter materials. The converter material is placed over Silicon Carbide (SiC) in Fast Neutron detectors (FNDs) to achieve higher neutron detection efficiency as compared to bare SiC FNDs. Hydrogenous converter material such as High-Density Polyethylene (HDPE) is preferred over other converter materials due to the virtue of its high elastic scattering reaction cross-section for fast neutron detection at room temperature. Upon interaction with fast neutrons, hydrogenous converter material generates recoil protons which liberate e-hole pairs in the active region of SiC detector to provide a detector signal. The neutron detection efficiency offered by HDPE converter is compared with several other hydrogenous materials viz., 1) Lithium Hydride (LiH), 2) Perylene, 3) PTCDA . It is found that, HDPE, though providing highest efficiency among various studied materials, cannot withstand high temperature and harsh radiation environment. On the other hand, perylene and PTCDA can sustain harsh environments, but yields low efficiency. The analysis carried out reveals that LiH is a better material for neutron to other charge particle conversion with competent efficiency and desired radiation hardness. Further, the thickness of LiH has also been optimized for various mono-energetic neutron beams and Am-Be neutron source generating a neutron fluence of 109 neutrons/cm2. The optimized thickness of LiH converter for fast neutron detection is found to be ~ 500 μm. However, the estimated efficiency for fast neutron detection is only 0.1%, which is deemed to be inadequate for reliable detection of neutrons. A sensitivity study has also been done investigating the gamma background effect on the neutron detection efficiency for various energy threshold of Low-Level Discriminator (LLD). The detection

  19. Radiation hardness investigation of avalanche photodiodes for the Projectile Spectator Detector readout at the Compressed Baryonic Matter experiment

    Czech Academy of Sciences Publication Activity Database

    Kushpil, Vasilij; Mikhaylov, Vasily; Kushpil, Svetlana; Tlustý, Pavel; Svoboda, Ondřej; Kugler, Andrej

    2015-01-01

    Roč. 787, JUL (2015), s. 117-120 ISSN 0168-9002 R&D Projects: GA MŠk LG12007; GA MŠk LG14004; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : avalanche photodiodes * single protons detection * radiation hardness * neutron irradiation tests * compressed Baryonic Matter experiment * Projectile Spectator Detector Subject RIV: BG - Nuclear, Atomic and Molecular Physics , Colliders Impact factor: 1.200, year: 2015

  20. An Evolutionary Algorithm for Feature Subset Selection in Hard Disk Drive Failure Prediction

    Science.gov (United States)

    Bhasin, Harpreet

    2011-01-01

    Hard disk drives are used in everyday life to store critical data. Although they are reliable, failure of a hard disk drive can be catastrophic, especially in applications like medicine, banking, air traffic control systems, missile guidance systems, computer numerical controlled machines, and more. The use of Self-Monitoring, Analysis and…

  1. Final Technical Report Radiation Hard Tight Pitch GaInP SPAD Arrays for High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Harmon, Eric

    2018-01-26

    The specialized photodetectors used in high energy physics experiments often need to remain extremely sensitive for years despite radiation induced damage caused by the constant bombardment of high energy particles. To solve this problem, LightSpin Technologies, Inc. in collaboration with Prof. Bradley Cox and the University of Virginia is developing radiation-hard GaInP photodetectors which are projected to be extraordinarily radiation hard, theoretically capable of withstanding a 100,000-fold higher radiation dose than silicon. In this Phase I SBIR project, LightSpin investigated the performance and radiation hardness of fifth generation GaInP SPAD arrays. These fifth generation devices used a new planar processing approach that enables very tight pitch arrays to be produced. High performance devices with SPAD pitches of 11, 15, and 25 μm were successfully demonstrated, which greatly increased the dynamic range and maximum count rate of the devices. High maximum count rates are critical when considering radiation hardness, since radiation damage causes a proportional increase in the dark count rate, causing SPAD arrays with low maximum count rates (large SPAD pitches) to fail. These GaInP SPAD array Photomultiplier Chips™ were irradiated with protons, electrons, and neutrons. Initial irradiation results were disappointing, with the post-irradiation devices exhibiting excessively high dark currents. The degradation was traced to surface leakage currents that were largely eliminated through the use of trenches etched around the exterior of the Photomultiplier Chip™ (not between SPAD elements). A second round of irradiations on Photomultiplier Chips™ with trenches proved substantially more successful, with post-irradiation dark currents remaining relatively low, though dark count rates were observed to increase at the highest doses. Preliminary analysis of the post-irradiation devices is promising … many of the irradiated Photomultiplier Chips™ still

  2. Predicted Radiation Exposure from Mining at Kvanefjeld

    DEFF Research Database (Denmark)

    Nielsen, Sven Poul; Roos, Per; Andersson, Kasper Grann

    Baseline surveys of gamma radiation and environmental radioactivity have been carried out by Greenland Minerals and Energy Ltd (GMEL) to show existing levels in the town of Narsaq and in the Kvanefjeld project area. Radiation levels in Narsaq are low but elevated in the project area due the prese......Baseline surveys of gamma radiation and environmental radioactivity have been carried out by Greenland Minerals and Energy Ltd (GMEL) to show existing levels in the town of Narsaq and in the Kvanefjeld project area. Radiation levels in Narsaq are low but elevated in the project area due...... the presence of large uranium and thorium deposits in Kvanefjeld. These deposits are also the reason that radon in outdoor air show elevated concentrations in Narsaq and in the project area. It is recommended that future monitoring of external exposure and radon should be based on measurement techniques using...

  3. Prediction of hourly solar radiation with multi-model framework

    International Nuclear Information System (INIS)

    Wu, Ji; Chan, Chee Keong

    2013-01-01

    Highlights: • A novel approach to predict solar radiation through the use of clustering paradigms. • Development of prediction models based on the intrinsic pattern observed in each cluster. • Prediction based on proper clustering and selection of model on current time provides better results than other methods. • Experiments were conducted on actual solar radiation data obtained from a weather station in Singapore. - Abstract: In this paper, a novel multi-model prediction framework for prediction of solar radiation is proposed. The framework started with the assumption that there are several patterns embedded in the solar radiation series. To extract the underlying pattern, the solar radiation series is first segmented into smaller subsequences, and the subsequences are further grouped into different clusters. For each cluster, an appropriate prediction model is trained. Hence a procedure for pattern identification is developed to identify the proper pattern that fits the current period. Based on this pattern, the corresponding prediction model is applied to obtain the prediction value. The prediction result of the proposed framework is then compared to other techniques. It is shown that the proposed framework provides superior performance as compared to others

  4. Influence of transfer gate design and bias on the radiation hardness of pinned photodiode CMOS image sensors

    International Nuclear Information System (INIS)

    Goiffon, V.; Estribeau, M.; Cervantes, P.; Molina, R.; Magnan, P.; Gaillardin, M.

    2014-01-01

    The effects of Cobalt 60 gamma-ray irradiation on pinned photodiode (PPD) CMOS image sensors (CIS) are investigated by comparing the total ionizing dose (TID) response of several transfer gate (TG) and PPD designs manufactured using a 180 nm CIS process. The TID induced variations of charge transfer efficiency (CTE), pinning voltage, equilibrium full well capacity (EFWC), full well capacity (FWC) and dark current measured on the different pixel designs lead to the conclusion that only three degradation sources are responsible for all the observed radiation effects: the pre-metal dielectric (PMD) positive trapped charge, the TG sidewall spacer positive trapped charge and, with less influence, the TG channel shallow trench isolation (STI) trapped charge. The different FWC evolutions with TID presented here are in very good agreement with a recently proposed analytical model. This work also demonstrates that the peripheral STI is not responsible for the observed degradations and thus that the enclosed layout TG design does not improve the radiation hardness of PPD CIS. The results of this study also lead to the conclusion that the TG OFF voltage bias during irradiation has no influence on the radiation effects. Alternative design and process solutions to improve the radiation hardness of PPD CIS are discussed. (authors)

  5. Influence of variable tungsten valency on optical transmittance and radiation hardness of lead tungstate (PWO) scintillation crystals

    CERN Document Server

    Burachas, S; Makov, I; Saveliev, Yu; Ippolitov, M S; Man'ko, V; Nikulin, S P; Nyanin, A; Vasilev, A; Apanasenko, A; Tamulaitis, G

    2003-01-01

    A new approach to interpret the radiation hardness of PbWO//4 (PWO) scintillators is developed by revealing importance of the inclusions of tungsten oxides WO//3//-//x with variable valency. It is demonstrated that the influence of the ionizing radiation on PWO is, in many aspects, similar to the effect of the high-temperature annealing in oxygenless ambient. In both cases, a valency change of the tungsten oxides is initiated and results in induced absorption and, consequently, in crystal coloration. In the PWO crystals doped with L//2O//3 (L = Y, La, Gd), the radiation hardness and the optical properties are mainly affected by inclusions of W//1//-//yL//yO//3//- //x (0 less than x less than 0.3) instead of inclusions of WO//3//- //x prevailing in the undoped samples. It is demonstrated that the radiation-induced bleaching and the photochromic effect of PWO are caused by phase transitions in the inclusions of tungsten oxide. Thermodynamic conditions for the phase transitions are discussed and the optimal oxid...

  6. Investigation on the improved radiation hardness of silicon detectors with high oxygen concentration

    International Nuclear Information System (INIS)

    Moll, M.; Fretwurst, E.; Lindstroem, G.

    2000-01-01

    We present an investigation on the influence of the oxygen concentration on radiation-induced changes in the effective doping concentration of silicon detectors. Diodes fabricated from silicon with interstitial oxygen content ranging from below 2x10 14 to 9x10 17 cm -3 have been irradiated with fast neutrons up to a fluence of 2x10 15 cm -2 . Our main interest focused on the so-called stable damage component in the change of the effective doping concentration being of prime importance for the application of silicon detectors in high-energy physics experiments. We demonstrate, that with a high oxygen enrichment the donor removal is appreciably reduced, reaching a value of only 10% of the initial doping concentration for [O i ]=9x10 17 cm -3 , while for normal detector grade material with [O i ] below 5x10 16 cm -3 that value is 60-90%. Furthermore, we show that the fluence proportional introduction of stable acceptors is independent of the oxygen concentration with an averaged introduction rate of (1.49±0.03)x10 -2 cm -1 . Only one material was found exhibiting a significantly smaller value of about 0.6x10 -2 cm -1 and thus indicating the possibility to suppress the radiation-induced acceptor creation by material modification. Finally, we show that the experimental findings disagree in several important aspects with predictions made by microscopic defect kinetics models, leaving the physical background of some of the measured data as an open question

  7. Techniques for predicting environment electromagnetic radiation at satellite ground station

    International Nuclear Information System (INIS)

    Xu Peiji

    1987-01-01

    The measurement theories, techniques, and calculation methods on public exposure level of electromagnetic radiation at satellite ground station are described for the purpose of enviroment protection and research of EM compatibility. According to the results of the measurement and calculation, it is possible to predict the effects of electromagnetic radiation to environment at satellite ground station

  8. Atomically Smooth Epitaxial Ferroelectric Thin Films for the Development of a Nonvolatile, Ultrahigh Density, Fast, Low Voltage, Radiation-Hard Memory

    National Research Council Canada - National Science Library

    Ahn, Charles H

    2006-01-01

    The goal of this research is to fabricate atomically smooth, single crystalline, complex oxide thin film nanostructures for use in a nonvolatile, ultrahigh density, fast, low voltage, radiation-hard memory...

  9. The ionizing radiation environment of LDEF prerecovery predictions

    Science.gov (United States)

    Watts, John W., Jr.; Derrickson, James H.; Parnell, T. A.; Fishman, G. J.; Harmon, A.; Benton, E. V.; Frank, A. L.; Heinrich, Wolfgang

    1991-01-01

    The Long Duration Exposure Facility (LDEF) was exposed to several sources of ionizing radiation while in orbit. The principal ones were trapped belt protons and electrons, galactic cosmic rays, and albedo particles (protons and neutrons) from the atmosphere. Large solar flares in 1989 may have caused a small contribution. Prior to the recovery of the spacecraft, a number of calculations and estimates were made to predict the radiation exposure of the spacecraft and experiments. These were made to assess whether measurable radiation effects might exist, and to plan the analysis of the large number of radiation measurements available on the LDEF. Calculations and estimates of total dose, particle fluences, linear energy transfer spectra, and induced radioactivity were made. The principal sources of radiation is described, and the preflight predictions are summarized.

  10. Dense plasma focus PACO as a hard X-ray emitter: a study on the radiation source

    OpenAIRE

    Supán, L.; Guichón, S.; Milanese, Maria Magdalena; Niedbalski, Jorge Julio; Moroso, Roberto Luis; Acuña, H.; Malamud, Florencia

    2016-01-01

    The radiation in the X-ray range detected outside the vacuum chamber of the dense plasma focus (DPF) PACO, are produced on the anode zone. The zone of emission is studied in a shot-to-shot analysis, using pure deuterium as filling gas. We present a diagnostic method to determine the place and size of the hard X-ray source by image analysis of high density radiography plates. Fil: Supán, L.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Insti...

  11. Breakup and then makeup: a predictive model of how cilia self-regulate hardness for posture control.

    Science.gov (United States)

    Bandyopadhyay, Promode R; Hansen, Joshua C

    2013-01-01

    Functioning as sensors and propulsors, cilia are evolutionarily conserved organelles having a highly organized internal structure. How a paramecium's cilium produces off-propulsion-plane curvature during its return stroke for symmetry breaking and drag reduction is not known. We explain these cilium deformations by developing a torsional pendulum model of beat frequency dependence on viscosity and an olivo-cerebellar model of self-regulation of posture control. The phase dependence of cilia torsion is determined, and a bio-physical model of hardness control with predictive features is offered. Crossbridge links between the central microtubule pair harden the cilium during the power stroke; this stroke's end is a critical phase during which ATP molecules soften the crossbridge-microtubule attachment at the cilium inflection point where torsion is at its maximum. A precipitous reduction in hardness ensues, signaling the start of ATP hydrolysis that re-hardens the cilium. The cilium attractor basin could be used as reference for perturbation sensing.

  12. Radiation hardness assessment of the charge-integrating hybrid pixel detector JUNGFRAU 1.0 for photon science

    Energy Technology Data Exchange (ETDEWEB)

    Jungmann-Smith, J. H., E-mail: jsmith@magnet.fsu.edu; Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Greiffenberg, D.; Jaggi, A.; Maliakal, D.; Mayilyan, D.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruder, Ch.; Schädler, L.; Schmitt, B.; Shi, X.; Tinti, G. [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Cartier, S. [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Institute for Biomedical Engineering, University and ETHZ, 8092 Zürich (Switzerland); Medjoubi, K. [Synchrotron Soleil, L’Orme des Merisiers, Saint-Aubin–BP 48, 91192 GIF-sur-Yvette Cedex (France)

    2015-12-15

    JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications in free electron lasers, particularly SwissFEL, and synchrotron light sources. JUNGFRAU is an automatic gain switching, charge-integrating detector which covers a dynamic range of more than 10{sup 4} photons of an energy of 12 keV with a good linearity, uniformity of response, and spatial resolving power. The JUNGFRAU 1.0 application-specific integrated circuit (ASIC) features a 256 × 256 pixel matrix of 75 × 75 μm{sup 2} pixels and is bump-bonded to a 320 μm thick Si sensor. Modules of 2 × 4 chips cover an area of about 4 × 8 cm{sup 2}. Readout rates in excess of 2 kHz enable linear count rate capabilities of 20 MHz (at 12 keV) and 50 MHz (at 5 keV). The tolerance of JUNGFRAU to radiation is a key issue to guarantee several years of operation at free electron lasers and synchrotrons. The radiation hardness of JUNGFRAU 1.0 is tested with synchrotron radiation up to 10 MGy of delivered dose. The effect of radiation-induced changes on the noise, baseline, gain, and gain switching is evaluated post-irradiation for both the ASIC and the hybridized assembly. The bare JUNGFRAU 1.0 chip can withstand doses as high as 10 MGy with minor changes to its noise and a reduction in the preamplifier gain. The hybridized assembly, in particular the sensor, is affected by the photon irradiation which mainly shows as an increase in the leakage current. Self-healing of the system is investigated during a period of 11 weeks after the delivery of the radiation dose. Annealing radiation-induced changes by bake-out at 100 °C is investigated. It is concluded that the JUNGFRAU 1.0 pixel is sufficiently radiation-hard for its envisioned applications at SwissFEL and synchrotron beam lines.

  13. Development of radiation-hard electric connector with ball bearing for in-vessel remote maintenance equipment of ITER

    International Nuclear Information System (INIS)

    Ito, Akira; Obara, Kenjiro; Tada, Eisuke; Morita, Yousuke; Yagi, Toshiaki; Iida, Kazuhisa; Sato, Masaru.

    1997-12-01

    Development of radiation-hard electric connector with ball bearing for in-vessel remote maintenance equipment of ITER (International Thermonuclear Experimental Reactor) has been conducted. Since the in-vessel remote maintenance equipment is operated under the condition of 10 6 R/h gamma ray dose rate, the electric connector has to be radiation hard for an accumulation dose of 10 10 R. In addition, the simple attachment/removal mechanism is essential for remote operation. For this, the alumina (Al203) ceramics and a ball bearing were adopted to electric insulator and plug (male) of connector, respectively. The handling tests on attachment/removal of the connector were conducted by using master slave manipulator and general purpose robot with handling tool, and as a result, the validity of the attachment/removal mechanism was verified. In the gamma ray irradiation tests, which are under way, no degradation in break down voltage (1000V 1min.) up to 10 10 R was confirmed. However insulation resistance and contact resistance between contact pin and contact socket were deteriorated in proportion to the accumulation dose. Increase of contact resistance is considered due to an erosion of contact pin. (author)

  14. Recent Progress in Synchrotron Radiation Photoemission Spectroscopy of Solids : Applications of VUV, Soft and Hard X-Ray Radiation

    International Nuclear Information System (INIS)

    Taniguchi, M.

    2004-01-01

    The Hiroshima Synchrotron Radiation Center is a common facility for both research and education in the field of synchrotron radiation science. The operation of the light source was started from March 1998. The storage ring can be operated at 700 MeV with a critical energy of 873 eV. The machine has a racetrack shape with a circumference of 22 m, and has 14 photon beam ports. The maximum operational current is 300 mA, and the beam lifetime is longer than 6 h at 200 mA. Of total 13 beamlines introduced so far, three beamlines are dedicated to photoemission spectroscopy (PES). An available photon-energy range is hν=26-300 eV. A hemispherical photoelectron analyzer is equipped at the end station. Total energy resolution has been achieved to ∼ 15 meV at hν=100 eV. The photon-energy range is hν=4-40 eV and total energy resolution is ∼ 4.5 meV at hν=7 eV. Although total energy resolution has been achieved to ∼25 meV at hν=80 eV, we usually carry out the PES experiments. The PES spectra taken at hν∼7 eV provide information on the conduction band electrons. In order to investigate the bulk-originated electronic structure we started the hard x-ray PES experiments with a total energy resolution of ∼ 270 meV. Thus, we promote the research project with use of light in a wide energy-range (7 eV-6 keV). 1) Unusual energy gap formation in the Kondo semiconductor CeRhAs has attracted much interest for its unusual energy gap formation or metal-to-insulator transition as temperature decreases. The energy gap is assumed to be formed by the temperature dependence of the c-f hybridization. By means of resonant PES, we could observe a energy-gap structure in the Ce 4f states. In order to observe As 4p state and Rh 4d state, we have measured the PES spectra at hν=7.9 eV, 40 eV and 6 keV, respectively, due to the photon-energy dependence of photoionization cross-section. From the spectra at hν=7.9 eV, we could see that the density of states (DOS) near E F decreases with

  15. Work Hard / Play Hard

    OpenAIRE

    Burrows, J.; Johnson, V.; Henckel, D.

    2016-01-01

    Work Hard / Play Hard was a participatory performance/workshop or CPD experience hosted by interdisciplinary arts atelier WeAreCodeX, in association with AntiUniversity.org. As a socially/economically engaged arts practice, Work Hard / Play Hard challenged employees/players to get playful, or go to work. 'The game changes you, you never change the game'. Employee PLAYER A 'The faster the better.' Employer PLAYER B

  16. Movie prediction of lung tumor for precise chasing radiation therapy

    International Nuclear Information System (INIS)

    Chhatkuli, Ritu Bhusal; Demachi, Kazuyuki; Kawai, Masaki; Sakakibara, Hiroshi; Uesaka, Mitsuru

    2012-01-01

    In recent years, precision for radiation therapy is a major challenge in the field of cancer treatment. When it comes to a moving organ like lungs, limiting the radiation to the target and sparing the surrounding healthy tissue is always a concern. It can induce the limit in the accuracy of area irradiated during lung cancer radiation therapy. Many methods have been introduced to compensate the motion in order to reduce the effect of radiation to healthy tissue due to respiratory motion. The motion of lung along with the tumor makes it very difficult to spare the healthy tissue during radiation therapy. The fear of this unintended damage to the neighboring tissue often limits the dose that can be applied to the tumor. The purpose of this research is the prediction of future motion images for the improvement of tumor tracking method. We predict the motion images by using principal component analysis (PCA) and multi-channel singular spectral analysis (MSSA) method. Time series x-ray images are used as training images. The motion images were successfully predicted and verified using the developed algorithm. The real time implementation of this method in future is believed to be significant for higher level of real time tumor tracking during radiation therapy. (author)

  17. Integrating Two-Dimensional Nanomaterials and Molecular Dielectrics for Radiation-Hard Non-Volatile Memory

    Data.gov (United States)

    National Aeronautics and Space Administration — The space radiation environment presents a significant hazard to the critical electronic components used in a variety of space applications. Many such applications...

  18. Radiation Hard Wide Temperature Range Mixed-Signal Components, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Low temperature survivability, high performance and radiation tolerance of electronics in combination is required for NASA's surface missions. Modern sub-micron CMOS...

  19. World Health Organization, radiofrequency radiation and health - a hard nut to crack (Review)

    OpenAIRE

    Hardell, Lennart

    2017-01-01

    In May 2011 the International Agency for Research on Cancer (IARC) evaluated cancer risks from radiofrequency (RF) radiation. Human epidemiological studies gave evidence of increased risk for glioma and acoustic neuroma. RF radiation was classified as Group 2B, a possible human carcinogen. Further epidemiological, animal and mechanistic studies have strengthened the association. In spite of this, in most countries little or nothing has been done to reduce exposure and educate people on health...

  20. Radiation-hard analog-to-digital converters for space and strategic applications

    Science.gov (United States)

    Gauthier, M. K.; Dantas, A. R. V.

    1985-01-01

    During the course of the Jet Propulsion Laboratory's program to study radiation-hardened analog-to-digital converters (ADCs), numerous milestones have been reached in manufacturers' awareness and technology development and transfer, as well as in user awareness of these developments. The testing of ADCs has also continued with twenty different ADCs from seven manufacturers, all tested for total radiation dose and three tested for neutron effects. Results from these tests are reported.

  1. Military Handbook: Management and Design Guidance Electromagnetic Radiation Hardness for Air Launched Ordnance Systems

    Science.gov (United States)

    1981-01-15

    system is attacted to the delivery aircraft until it Impacto a target, it is exposed to electromagnetic radiation from emitters aboard the delivery...homogeneous, isotropic, ambient medium may be a lossy dielectric. Antenna computations include cur- rent distribution, input impedance, radiation...permissible ambient interference level in the system, and when determining the expected signal-to-inter- ference ratio of the signal transmission circuits

  2. HVM-TP: A Time Predictable, Portable Java Virtual Machine for Hard Real-Time Embedded Systems

    DEFF Research Database (Denmark)

    Luckow, Kasper Søe; Thomsen, Bent; Korsholm, Stephan Erbs

    2014-01-01

    We present HVMTIME; a portable and time predictable JVM implementation with applications in resource-constrained hard real-time embedded systems. In addition, it implements the Safety Critical Java (SCJ) Level 1 specification. Time predictability is achieved by a combination of time predictable...... algorithms, exploiting the programming model of the SCJ specification, and harnessing static knowledge of the hosted SCJ system. This paper presents HVMTIME in terms of its design and capabilities, and demonstrates how a complete timing model of the JVM represented as a Network of Timed Automata can...... be obtained using the tool TetaSARTSJVM. Further, using the timing model, we derive Worst Case Execution Times (WCETs) and Best Case Execution Times (BCETs) of the Java Bytecodes....

  3. Radiation damage prediction system using damage function

    International Nuclear Information System (INIS)

    Tanaka, Yoshihisa; Mori, Seiji

    1979-01-01

    The irradiation damage analysis system using a damage function was investigated. This irradiation damage analysis system consists of the following three processes, the unfolding of a damage function, the calculation of the neutron flux spectrum of the object of damage analysis and the estimation of irradiation effect of the object of damage analysis. The damage function is calculated by applying the SAND-2 code. The ANISN and DOT3, 5 codes are used to calculate neutron flux. The neutron radiation and the allowable time of reactor operation can be estimated based on these calculations of the damage function and neutron flux. The flow diagram of the process of analyzing irradiation damage by a damage function and the flow diagram of SAND-2 code are presented, and the analytical code for estimating damage, which is determined with a damage function and a neutron spectrum, is explained. The application of the irradiation damage analysis system using a damage function was carried out to the core support structure of a fast breeder reactor for the damage estimation and the uncertainty evaluation. The fundamental analytical conditions and the analytical model for this work are presented, then the irradiation data for SUS304, the initial estimated values of a damage function, the error analysis for a damage function and the analytical results are explained concerning the computation of a damage function for 10% total elongation. Concerning the damage estimation of FBR core support structure, the standard and lower limiting values of damage, the permissible neutron flux and the allowable years of reactor operation are presented and were evaluated. (Nakai, Y.)

  4. Modelling of hardness prediction of magnesium alloys using artificial neural networks applications

    OpenAIRE

    L.A. Dobrzański; T. Tański; J. Trzaska; L. Čížek

    2008-01-01

    Purpose: In the following paper there have been presented the optimisation of heat treatment condition and structure of the MCMgAl12Zn1, MCMgAl9Zn1, MCMgAl6Zn1, MCMgAl3Zn1 magnesium cast alloy as-cast state and after a heat treatment.Design/methodology/approach: Working out of a neural network model for simulation of influence of temperature, solution heat treatment and ageing time and aluminium content on hardness of the analyzed magnesium cast alloys.Findings: The different heat treatment k...

  5. World Health Organization, radiofrequency radiation and health - a hard nut to crack (Review).

    Science.gov (United States)

    Hardell, Lennart

    2017-08-01

    In May 2011 the International Agency for Research on Cancer (IARC) evaluated cancer risks from radiofrequency (RF) radiation. Human epidemiological studies gave evidence of increased risk for glioma and acoustic neuroma. RF radiation was classified as Group 2B, a possible human carcinogen. Further epidemiological, animal and mechanistic studies have strengthened the association. In spite of this, in most countries little or nothing has been done to reduce exposure and educate people on health hazards from RF radiation. On the contrary ambient levels have increased. In 2014 the WHO launched a draft of a Monograph on RF fields and health for public comments. It turned out that five of the six members of the Core Group in charge of the draft are affiliated with International Commission on Non-Ionizing Radiation Protection (ICNIRP), an industry loyal NGO, and thus have a serious conflict of interest. Just as by ICNIRP, evaluation of non-thermal biological effects from RF radiation are dismissed as scientific evidence of adverse health effects in the Monograph. This has provoked many comments sent to the WHO. However, at a meeting on March 3, 2017 at the WHO Geneva office it was stated that the WHO has no intention to change the Core Group.

  6. A mixed analog-digital radiation hard technology for high energy physics electronics DMILL (Durci Mixte sur Isolant Logico-Linéaire)

    CERN Document Server

    Beuville, E; Borgeaud, P; Fourches, N T; Rouger, M; Blanc, J P; Bruel, M; Delevoye-Orsier, E; Gautier, J; Du Port de Pontcharra, J; Truche, R; Dupont-Nivet, E; Flament, O; Leray, J L; Martin, J L; Montaron, J; Borel, G; Brice, J M; Chatagnon, P; Terrier, C; Aubert, Jean-Jacques; Delpierre, P A; Habrard, M C; Potheau, R; CERN. Geneva. Detector Research and Development Committee

    1992-01-01

    The high radiation level expected in the inner regions of the high luminosity LHC detectors (gamma and neutron) will require radiation hardened electronics. A consortium between the CEA (Commissariat a l'Energie Atomique) and Thomson TMS (Thomson Composants Militaires et Spatiaux) has been created to push for the development and the industrialization of a nascent technology which looks particularly adapted to the needs of HEP electronics. This technology, currently under development at the LETI(CEA), uses a SIMOX substrate with an epitaxial silicon film. It includes CMOS, JFETs and vertical bipolar transistors with a potential multi-megarad hardness. The CMOS and bipolar transistors constitute a rad-hard BiCMOS which will be useful to design analog and digital high-speed architectures. JFETs, which have intrinsically high hardness behaviour and low noise performances even at low temperature will enable very rad-hard, low noise front end electronics to be designed. Present results, together with the improvemen...

  7. Custom high-reliability radiation-hard CMOS-LSI circuit design

    International Nuclear Information System (INIS)

    Barnard, W.J.

    1981-01-01

    Sandia has developed a custom CMOS-LSI design capability to provide high reliability radiation-hardened circuits. This capability relies on (1) proven design practices to enhance reliability, (2) use of well characterized cells and logic modules, (3) computer-aided design tools to reduce design time and errors and to standardize design definition, and (4) close working relationships with the system designer and technology fabrication personnel. Trade-offs are made during the design between circuit complexity/performance and technology/producibility for high reliability and radiation-hardened designs to result. Sandia has developed and is maintaining a radiation-hardened bulk CMOS technology fabrication line for production of prototype and small production volume parts

  8. GfW-handbook for irradiation test guidelines for radiation hardness of electronic components

    International Nuclear Information System (INIS)

    Braeunig, D.; Wulf, F.; Gaebler, W.; Boden, A.

    1982-12-01

    The purpose of the report is to propose irradiation test methods so that a standardized application of the methods can lead to a better comparison of test results. The interaction of different radiation species with matter - ionization and displacement - is described. Application of appropriate radiation sources, dosimetry problems, and shielding for simulating space radiation effects by laboratory testing is discussed. The description and characteristics of the irradiation sources are presented. Flowcharts of the planning and running of irradiation tests are given. Guidelines for running the tests are established, test methods and test circuits are proposed. The test system offers the capability of measuring devices also of high complexity up to microprocessors. The test results are collected regularly and are published in GfW-Handbook TN53/08, 'Data Compilation of Irradiation Tested Electronic Components'. (orig./HP) [de

  9. Radiation-hard, high efficiency InP solar cell and panel development

    International Nuclear Information System (INIS)

    Keavney, C.J.; Vernon, S.M.; Haven, V.E.; Nowlan, M.J.; Walters, R.J.; Slatter, R.L.; Summers, G.P.

    1991-01-01

    Indium phosphide solar cells with efficiencies over 19% (Air mass zero, 25 degrees C) and area of 4 cm 2 have been made and incorporated into prototype panels. The panels will be tested in space to confirm the high radiation resistance expected from InP solar cells, which makes the material attractive for space use, particularly in high-radiation orbits. Laboratory testing indicated an end-of-life efficiency of 15.5% after 10 15 1 MeV electrons, and 12% after 10 16 . These cells are made by metalorganic chemical vapor deposition, and have a shallow homojunction structure. The manufacturing process is amendable to scale-up to larger volumes; more than 200 cells were produced in the laboratory operation. Cell performance, radiation degradation, annealing behavior, and results of deep level transient spectroscopy studies are presented in this paper

  10. Investigation of characteristics and radiation hardness of the Beetle 1.0 front-end chip

    CERN Document Server

    Van Bakel, N; Jans, E; Klous, S; Verkooijen, H

    2001-01-01

    Noise characteristics of the Beetle 1.0 front-end chip have been investigated as a function of input capacitance. Values for the equivalent noise charge and ballastic deficit have been extracted. Amplification and pulse shape have been studied by varying the bias settings over a wide range. Results are compared with simulations that include realistic impedances at the input and output. The chip has been subjected to 10 Mrad of radiation. Subsequently, its behaviour is measured again and compared to that preceeding the irradiation. Observed radiation damage effects are discussed.

  11. Radiation hardness and qualification of semiconductor electronic devices for nuclear reactors

    International Nuclear Information System (INIS)

    Friant, A.; Payat, R.

    1984-05-01

    After a brief review of radiation effects in semiconductors and radiation damage in semiconductor devices, the problems of qualification of electronic equipment to be used in nuclear reactors are compared to those relative to nuclear weapons or space experiments. The conclusion is that data obtained at very high dose rates or under pulsed irradiation in weapons and space programs should not be directly applied to nuclear plant instrumentation. The need for a specific qualification of semiconductor devices appropriate for nuclear reactors is emphasized. Some irradiation studies at IRDI/DEIN (CEN-Saclay) are related [fr

  12. Radiation hardness and lifetime studies of LEDs and VCSELs for the optical readout of the ATLAS SCT

    CERN Document Server

    Beringer, J; Mommsen, R K; Nickerson, R B; Weidberg, A R; Monnier, E; Hou, H Q; Lear, K L

    1999-01-01

    We study the radiation hardness and the lifetime of Light Emitting Diodes (LEDs) and Vertical Cavity Surface Emitting Laser diodes (VCSELs) in the context of the development of the optical readout for the ATLAS SemiConductor Tracker (SCT) at LHC. About 170 LEDs from two different manufacturers and about 130 VCSELs were irradiated with neutron and proton fluences equivalent to (and in some cases more than twice as high as) the combined neutral and charged particle fluence of about 5x10 sup 1 sup 4 n (1 MeV eq. in GaAs)/cm sup 2 expected in the ATLAS inner detector. We report on the radiation damage and the conditions required for its partial annealing under forward bias, we calculate radiation damage constants, and we present post-irradiation failure rates for LEDs and VCSELs. The lifetime after irradiation was investigated by operating the diodes at an elevated temperature of 50 degree sign C for several months, resulting in operating times corresponding to up to 70 years of operation in the ATLAS SCT. From o...

  13. Studies for the LHCb SciFi Tracker - Development of Modules from Scintillating Fibres and Tests of their Radiation Hardness

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00341158

    The LHCb detector will see a major upgrade in the LHC long shutdown 2, which is planned for 2019/20. Among others, the tracking stations, currently realised as silicon strip and drift tube detectors, will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker is based on scintillating fibres with a diameter of $\\text 250 \\mu m$, read out by multichannel silicon photomultipliers. The two major challenges related to the fibres are the radiation damage of the light guidance and the production of precise multi-layer fibre mats. This thesis presents radiation hardness studies performed with protons at the tandem accelerator at Forschungszentrum Garching and in situ in the LHCb cavern. The obtained results are combined with additional data of the LHCb SciFi group and two different wavelength dependent models of the radiation induced attenuation are determined. These are used to simulate the relative light yield, for both models it drops to $83 \\%$ on average at the end of the nominal lifetime of ...

  14. Studies for the LHCb SciFi tracker. Development of modules from scintillating fibres and tests of their radiation hardness

    Energy Technology Data Exchange (ETDEWEB)

    Ekelhof, Robert Jan

    2016-05-18

    The LHCb detector will see a major upgrade in the LHC long shutdown 2, which is planned for 2019/20. Among others, the tracking stations, currently realised as silicon strip and drift tube detectors, will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker is based on scintillating fibres with a diameter of 250 μm, read out by multichannel silicon photomultipliers. The two major challenges related to the fibres are the radiation damage of the light guidance and the production of precise multi-layer fibre mats. This thesis presents radiation hardness studies performed with protons at the tandem accelerator at Forschungszentrum Garching and in situ in the LHCb cavern. The obtained results are combined with additional data of the LHCb SciFi group and two different wavelength dependent models of the radiation induced attenuation are determined. These are used to simulate the relative light yield, for both models it drops to 83% on average at the end of the nominal lifetime of the SciFi Tracker. A machine and techniques to produce multi-layer fibre mats were developed and optimised. Procedures for the production and alignment are described. These are implemented in the serial production of the SciFi modules which will start in the second quarter 2016.

  15. Study of Radiation Hardness of Lattice Matched AlInN/GaN HEMT Heterostructures

    Science.gov (United States)

    2016-10-01

    the wedge to a nanomanipulator probe. d- Lifting -out of the wedge from the bulk sample. e- Attachment of a portion of the wedge to one of the silicon...out by subcontractor Scientic, Inc. The exposures were conducted at the Gamma Radiation Facility at NAVSEA Crane division with doses up to ~6 Mrad

  16. Radiation effects and hardness of semiconductor electronic devices for nuclear industry

    International Nuclear Information System (INIS)

    Payat, R.; Friant, A.

    1988-01-01

    After a brief review of industrial and nuclear specificity and radiation effects in electronics components (semiconductors) the need for a specific test methodology of semiconductor devices is emphasized. Some studies appropriate for nuclear industry at D. LETI/DEIN/CEN-SACLAY are related [fr

  17. Investigation of single defects created in crystals by laser emission and hard radiation

    International Nuclear Information System (INIS)

    Martynovich, E F; Dresvyanskiy, V P; Boychenko, S V; Rakevich, A L; Zilov, S A; Bagayev, S N

    2017-01-01

    The possibility of identifying radiation-created quantum systems via the characteristics of quantum trajectories of luminescence intensity measured on individual centers by confocal scanning fluorescence microscopy with the time-correlated single photon counting has been studied. Calculations of the quantum trajectories have been carried out by the density matrix method. Experimental studies have been carried out using a confocal microscope. (paper)

  18. Evaluation of radiation effects on dental enamel hardness and dental restorative materials

    International Nuclear Information System (INIS)

    Adachi, Lena Katekawa; Saiki, Mitiko; Campos, Tomie Nakakuki

    2000-01-01

    This research presents the results of the microhardness of human dental enamel and of the following dental restorative materials: three dental porcelains - Ceramco II, Finesse and Noritake, and two resin restorative materials - Artglass and Targis, for materials submitted to different times of irradiation at the IEA-R1m nuclear reactor under a thermal neutron flux of 10 12 n cm -2 .s -1 . The results obtained indicated that there is a decrease of the surface microhardness when the enamel is irradiated for 1 h and when dental materials are irradiated for 3 h. However, enamels irradiated for 30 min. did not show significant change of their surface hardness. Therefore, the selection of irradiation time is an important factor to be considered when irradiated teeth or dental materials are used in the investigations of their properties. (author)

  19. Radiation hardness of β-Ga2O3 metal-oxide-semiconductor field-effect transistors against gamma-ray irradiation

    Science.gov (United States)

    Wong, Man Hoi; Takeyama, Akinori; Makino, Takahiro; Ohshima, Takeshi; Sasaki, Kohei; Kuramata, Akito; Yamakoshi, Shigenobu; Higashiwaki, Masataka

    2018-01-01

    The effects of ionizing radiation on β-Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) were investigated. A gamma-ray tolerance as high as 1.6 MGy(SiO2) was demonstrated for the bulk Ga2O3 channel by virtue of weak radiation effects on the MOSFETs' output current and threshold voltage. The MOSFETs remained functional with insignificant hysteresis in their transfer characteristics after exposure to the maximum cumulative dose. Despite the intrinsic radiation hardness of Ga2O3, radiation-induced gate leakage and drain current dispersion ascribed respectively to dielectric damage and interface charge trapping were found to limit the overall radiation hardness of these devices.

  20. Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope - Part 1

    Science.gov (United States)

    El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; Maghraby, Ahmed; El-Zainy, Medhat

    2011-12-01

    In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope. For doses up to 0.5 Gy, there was no evidence of the existence of cracks on the enamel surface. With 1 Gy irradiation dose, cracks were clearly observed with localized erosive areas. At 2 Gy irradiation dose, the enamel showed morphological alterations as disturbed prismatic and interprismatic areas. An increase in dentinal tubules diameter and a contemporary inter-tubular dentine volume decrease were observed with higher irradiation dose. Concerning cementum, low doses,<0.5 Gy, showed surface irregularities and with increase in the irradiation dose to≥1 Gy, noticeable surface irregularities and erosive areas with decrease in Sharpey's fiber sites were observed. These observations could shed light on the hazardous effects of irradiation fields to the functioning of the human teeth.

  1. Study on efficiency of multi-wire tungsten moderator for slow positron source on SPring-8 hard synchrotron radiation

    International Nuclear Information System (INIS)

    Plokhoi, Vladimir; Kandiev, Yadgar; Samarin, Sergey; Malyshkin, Gennady; Baidin, Grigory; Litvinenko, Igor; Nikitin, Valery

    1999-01-01

    The paper provides results of numeric simulations of in-target positron production process, processes of moderation, thermalization, diffusion, and reemission of positrons in high efficiency multi-wire moderator made of tungsten monocrystalline wire with regular wire spacing. The paper looks into dynamics of slow positrons in the moderator's vacuum gaps taking into account of external fields. The possibility for using multi-wire moderator with non-regular structure - multi-layer w ire felt m oderator is discussed. According to maximal estimate the multi-wire moderators can reach very high efficiency of fast-slow positron transformation ∼ 10 -2 . Using such moderator the intensity of slow positron source on hard synchrotron radiation of Spring-8 can reach the level of ∼10 11 e + /s. (author)

  2. Systematic study of radiation hardness of single crystal CVD diamond material investigated with an Au beam and IBIC method

    Energy Technology Data Exchange (ETDEWEB)

    Pietraszko, Jerzy; Koenig, Wolfgang; Traeger, Michael [GSI, Darmstadt (Germany); Draveny, Antoine; Galatyuk, Tetyana [TU, Darmstadt (Germany); Grilj, Veljko [RBI, Zagreb (Croatia); Collaboration: HADES-Collaboration

    2016-07-01

    For the future high rate CBM experiment at FAIR a radiation hard and fast beam detector is required. The detector has to perform precise T0 measurement (σ<50 ps) and should also offer decent beam monitoring capability. These tasks can be performed by utilizing single-crystal Chemical Vapor Deposition (ScCVD) diamond based detector. A prototype, segmented, detector have been constructed and the properties of this detector have been studied with a high current density beam (about 3.10{sup 6}/s/mm{sup 2}) of 1.23 A GeV Au ions in HADES. The irradiated detector properties have been studied at RBI in Zagreb by means of IBIC method. Details of the design, the intrinsic properties of the detectors and their performance after irradiation with such beam are reported.

  3. Radiation Damage Mechanism in PbWO4 Crystal and Radiation Hardness Quality Control of PWO Scintillators for CMS

    CERN Document Server

    Baccaro, Stefania; Borgia, Bruno; Cavallari, Francesca; Cecilia, Angelica; Dafinei, Ioan; Diemoz, Marcella; Lecoq, Paul; Longo, Egidio; Montecchi, Marco; Organtini, Giovanni; Salvatori, S

    1997-01-01

    The optical damage induced by UV light in PbWO4 crystals is found to be similar to that induced by g radiation. Due to the peculiarities of optical absorption in PbWO4, the damage induced by UV light is a bulk process. This fact has important consequences for the approach to be adopted both for the use of the crystal as scintillator and for the qualification methods foreseen in the Regional Centres of the ECAL CMS Collaboration.

  4. Radiation hardness of two CMOS prototypes for the ATLAS HL-LHC upgrade project

    CERN Document Server

    Huffman, B T; Arndt, K; Bates, R; Benoit, M; Di Bello, F; Blue, A; Bortoletto, D; Buckland, M; Buttar, C; Caragiulo, P; Das, D; Dopke, J; Dragone, A; Ehrler, F; Fadeyev, V; Galloway, Z; Grabas, H; Gregor, I M; Grenier, P; Grillo, A; Hoeferkamp, M; Hommels, L B A; John, J; Kanisauskas, K; Kenney, C; Kramberger, J; Liang, Z; Mandic, I; Maneuski, D; Martinez-McKinney, F; McMahon, S; Meng, L; Mikuž, M; Muenstermann, D; Nickerson, R; Peric, I; Phillips, P; Plackett, R; Rubbo, F; Segal, J; Seidel, S; Seiden, A; Shipsey, I; Song, W; Stanitzki, M; Su, D; Tamma, C; Turchetta, R; Vigani, L; olk, J; Wang, R; Warren, M; Wilson, F; Worm, S; Xiu, Q; Zhang, J; Zhu, H

    2016-01-01

    The LHC luminosity upgrade, known as the High Luminosity LHC (HL-LHC), will require the replacement of the existing silicon strip tracker and the transistion radiation tracker. Although a baseline design for this tracker exists the ATLAS collaboration and other non-ATLAS groups are exploring the feasibility of using CMOS Monolithic Active Pixel Sensors (MAPS) which would be arranged in a strip-like fashion and would take advantage of the service and support structure already being developed for the upgrade. Two test devices made with theAMSH35 process (a High voltage or HV CMOS process) have been subjected to various radiation environments and have performed well. The results of these tests are presented in this paper.

  5. Radiation hardness of plastic scintillators for the Tile Calorimeter of the ATLAS detector

    CERN Document Server

    Jivan, Harshna; The ATLAS collaboration

    2014-01-01

    The Tile Calorimeter of the ATLAS detector, is a hadronic calorimeter responsible for detecting hadrons as well as accommodating for the missing transverse energy that result from the p-p collisions within the LHC. Plastic scintillators form an integral component of this calorimeter due to their ability to undergo prompt fluorescence when exposed to ionising particles. The scintillators employed are specifically chosen for their properties of high optical transmission and fast rise and decay time which enables efficient data capture since fast signal pulses can be generated. The main draw-back of plastic scintillators however is their susceptibility to radiation damage. The damage caused by radiation exposure reduces the scintillation light yield and introduces an error into the time-of flight data acquired. During Run 1 of the LHC data taking period, plastic scintillators employed within the GAP region between the Tile Calorimeter’s central and extended barrels sustained a significant amount of damage. Wit...

  6. Radiation hardness of silicon detectors - a challenge from high-energy physics

    CERN Document Server

    Lindström, G; Fretwurst, E

    1999-01-01

    An overview of the radiation-damage-induced problems connected with the application of silicon particle detectors in future high-energy physics experiments is given. Problems arising from the expected hadron fluences are summarized and the use of the nonionizing energy loss for normalization of bulk damage is explained. The present knowledge on the deterioration effects caused by irradiation is described leading to an appropriate modeling. Examples are given for a correlation between the change in the macroscopic performance parameters and effects to be seen on the microscopic level by defect analysis. Finally possible ways are out-lined for improving the radiation tolerance of silicon detectors either by operational conditions, process technology or defect engineering.

  7. Radiation interlocks - The choice between conventional hard-wired logic and computer-based systems

    International Nuclear Information System (INIS)

    Crook, K.F.

    1987-01-01

    During the past few years, the use of computers in radiation safety systems has become more widespread. This is not surprising given the ubiquitous nature of computers in the modern technological world. But is a computer a good choice for the central logic element of a personnel safety system? Recent accidents at computer controlled medical accelerators would indicate that extreme care must be exercised if malfunctions are to be avoided. The Department of Energy (DOE) has recently established a sub-committee to formulate recommendations on the use of computers in safety systems for accelerators. This paper reviews the status of the committee's recommendations, and describes radiation protection interlock systems as applied to both accelerators and to irradiation facilities. Comparisons are made between the conventional (relay) approach and designs using computers

  8. Radiation interlocks: The choice between conventional hard-wired logic and computer-based systems

    International Nuclear Information System (INIS)

    Crook, K.F.

    1986-11-01

    During the past few years, the use of computers in radiation safety systems has become more widespread. This is not surprising given the ubiquitous nature of computers in the modern technological world. But is a computer a good choice for the central logic element of a personnel safety system. Recent accidents at computer controlled medical accelerators would indicate that extreme care must be exercised if malfunctions are to be avoided. The Department of Energy has recently established a sub-committee to formulate recommendations on the use of computers in safety systems for accelerators. This paper will review the status of the committee's recommendations, and describe radiation protection interlock systems as applied to both accelerators and to irradiation facilities. Comparisons are made between the conventional relay approach and designs using computers. 6 refs., 6 figs

  9. Radiation-hard ceramic Resistive Plate Chambers for forward TOF and T0 systems

    Energy Technology Data Exchange (ETDEWEB)

    Akindinov, A., E-mail: Alexander.Akindinov@cern.ch [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Dreyer, J.; Fan, X.; Kämpfer, B. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Kiselev, S. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Kotte, R.; Garcia, A. Laso [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Malkevich, D. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Naumann, L. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Nedosekin, A.; Plotnikov, V. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Stach, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Sultanov, R.; Voloshin, K. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation)

    2017-02-11

    Resistive Plate Chambers with ceramic electrodes are the main candidates for a use in precise multi-channel timing systems operating in high-radiation conditions. We report the latest R&D results on these detectors aimed to meet the requirements of the forward T0 counter at the CBM experiment. RPC design, gas mixture, limits on the bulk resistivity of ceramic electrodes, efficiency, time resolution, counting rate capabilities and ageing test results are presented.

  10. Parallel beam microradiography of dental hard tissue using synchrotron radiation and X-ray image magnification

    International Nuclear Information System (INIS)

    Takagi, S.; Chow, L.C.; Brown, W.E.; Dobbyn, R.C.; Kuriyama, M.

    1984-01-01

    A novel technique utilizing a highly parallel beam of monochromatic synchrotron radiation combined with X-ray image magnification has been used to obtain microradiographs of caries lesions in relatively thick tooth sections. Preliminary results reveal structural features not previously reported. This technique holds the promise of allowing one to follow the structural changes accompanying the formation, destruction and chemical repair of mineralized tissue in real time. (orig.)

  11. Technique for selection of transient radiation-hard junction-isolated integrated circuits

    International Nuclear Information System (INIS)

    Crowley, J.L.; Junga, F.A.; Stultz, T.J.

    1976-01-01

    A technique is presented which demonstrates the feasibility of selecting junction-isolated integrated circuits (JI/ICS) for use in transient radiation environments. The procedure guarantees that all PNPN paths within the integrated circuit are identified and describes the methods used to determine whether the paths represent latchup susceptible structures. Two examples of the latchup analysis are given involving an SSI and an LSI bipolar junction-isolated integrated circuit

  12. Radiation hardness and precision timing study of Silicon detectors for the CMS High Granularity Calorimeter (HGC)

    CERN Document Server

    Curras, E; Gallrapp, C; Gray, L; Mannelli, M; Meridiani, P; Moll, M; Nourbakhsh, S; Scharf, C; Silva, P; Steinbrueck, G; Tabarelli de Fatis, T; Vila, I

    2017-01-01

    The high luminosity upgraded LHC or Phase-II is expected to increase the instantaneous luminosity by a factor of 10 beyond the LHC's design value, expecting to deliver 250 fb^−1 per year for a further 10 years of operation. Under these conditions the performance degradation due to integrated radiation dose will need to be addressed. The CMS collaboration is planning to upgrade the forward calorimeters. The replacement is called the High Granularity Calorimeter (HGC) and it will be realized as a sampling calorimeter with layers of silicon detectors interleaved. The sensors will be realized as pad detectors with sizes of less that ∼1.0 cm^2 and an active thickness between 100 and 300 μm depending on the position, respectively, the expected radiation levels. For an integrated luminosity of 3000 fb^−1, the electromagnetic calorimetry will sustain integrated doses of 1.5 MGy (150 Mrads) and neutron fluences up to 10^16 neq/cm^2. A radiation tolerance study after neutron irradiation of 300, 200, and 100 μ...

  13. The MONOS memory transistor: application in a radiation-hard nonvolatile RAM

    International Nuclear Information System (INIS)

    Brown, W.D.

    1985-01-01

    The MONOS (metal-oxide-nitride-oxide-silicon) device is a prime candidate for use as the nonvolatile memory element in a radiation-hardened RAM (random-access memory). The endurance, retention and radiation properties of MONOS memory transistors have been studied as a function of post nitride deposition annealing. Following the nitride layer deposition, all devices were subjected to an 800 0 C oxidation step and some were then annealed at 900 0 C in nitrogen. The nitrogen anneal produces an increase in memory window size of approximately 40%. The memory window center of the annealed devices is shifted toward more positive voltages and is more stable with endurance cycling. Endurance cycling to 10 9 cycles produces a 20% increase in memory window size and a 60% increase in decay rate. For a radiation total dose of 10 6 rads (Si), the memory window size is essentially unchanged and the decay rate increases approximately 13%. A combination of 10 9 cycles and 10 6 rads (Si) reduces the decades of retention (in sec) from 6.3 to 4.3 for a +- 23-V 16-μsec write/erase pulse. (author)

  14. SIMON [Semi-Intelligent Mobile Observing Navigator] combines radiation hardness with computer power

    International Nuclear Information System (INIS)

    Weber, P.J.; Vanecek, C.W.

    1990-01-01

    SIMON - the Semi-Intelligent Mobile Observing Navigator - has been under development at the US Department of Energy's (DoE's) Savannah River Laboratory for four years. The robot's on-board intelligence units are designed to be radiation-resistant, making it able to function for extended periods within a remotely operated facility. In its current form, SIMON is being developed by the laboratory's Robotics Group for use in the site's production reactors, but it can be adapted for use in any nuclear facility, including commercial reactors. The challenge for Savannah River Laboratory engineers was to eliminate the need for human inspection of certain components. To do this, they designed a robot that could do three things for reactor operators: measure radiation; measure temperature; and provide televised views inside the reactor facility. To be useful, the robot has to be extremely mobile, and its components had to be able to survive months without maintenance in the radiation, temperature and humidity encountered in nuclear facilities. The robot also had to be cost-effective. (author)

  15. Burnout in radiation therapists: the predictive value of selected stressors

    International Nuclear Information System (INIS)

    Akroyd, Duane; Caison, Amy; Adams, Robert D.

    2002-01-01

    Purpose: As cancer caregivers, radiation therapists experience a variety of stresses that may develop into burnout, which has been demonstrated to impact patient care, employee health, and organizational effectiveness. The purpose of the study was to assess the levels of radiation therapists' burnout at three stages. Additionally, the ability of selected workplace variables to predict each of the three stages of burnout was examined. Methods and Materials: We used descriptive and inferential statistical analyses on reliable and valid instruments, which measured stress, burnout, and social support. Results: Radiation therapists have high levels of the first two stages of burnout: emotional exhaustion and depersonalization. Although personal stress, organizational stress, guidance, reassurance of worth, and work load predicted 50% or more of the variance in emotional exhaustion and depersonalization, their predictive ability for personal accomplishment was low. Conclusion: Efforts to alleviate burnout among radiation therapists within an organization should have positive effects, including increased quality of patient care, improved quality of work life, higher levels of job satisfaction, and commitment and lower staff turnover

  16. An integrated artificial neural networks approach for predicting global radiation

    International Nuclear Information System (INIS)

    Azadeh, A.; Maghsoudi, A.; Sohrabkhani, S.

    2009-01-01

    This article presents an integrated artificial neural network (ANN) approach for predicting solar global radiation by climatological variables. The integrated ANN trains and tests data with multi layer perceptron (MLP) approach which has the lowest mean absolute percentage error (MAPE). The proposed approach is particularly useful for locations where no available measurement equipment. Also, it considers all related climatological and meteorological parameters as input variables. To show the applicability and superiority of the integrated ANN approach, monthly data were collected for 6 years (1995-2000) in six nominal cities in Iran. Separate model for each city is considered and the quantity of solar global radiation in each city is calculated. Furthermore an integrated ANN model has been introduced for prediction of solar global radiation. The acquired results of the integrated model have shown high accuracy of about 94%. The results of the integrated model have been compared with traditional angstrom's model to show its considerable accuracy. Therefore, the proposed approach can be used as an efficient tool for prediction of solar radiation in the remote and rural locations with no direct measurement equipment.

  17. Performance analysis of tracked panel according to predicted global radiation

    International Nuclear Information System (INIS)

    Chang, T.P.

    2009-01-01

    In this paper, the performance of a south facing single-axis tracked panel was analyzed according to global radiation predicted by empirical model. Mathematic expressions appropriate for single-axis tracking system were derived to calculate the radiation on it. Instantaneous increments of solar energy collected by the tracked panel relative to fixed panel are illustrated. The validity of the empirical model to Taiwan area will also be examined with the actual irradiation data observed in Taipei. The results are summarized as follows: the gains made by the tracked panel relative to a fixed panel are between 20.0% and 33.9% for four specified days of year, between 20.9% and 33.2% for the four seasons and 27.6% over the entire year. For latitudes below 65 deg., the yearly optimal tilt angle of a fixed panel is close to 0.8 times latitude, the irradiation ratio of the tracked panel to the fixed panel is about 1.3, which are smaller than the corresponding values calculated from extraterrestrial radiation, suggesting us that the installation angle should be adjusted toward a flatter angle and that the gain of the tracked panel will reduce while it works in cloudy climate or in air pollution environment. Although the captured radiation increases with the maximal rotation angle of panel, but the benefit on the global radiation case is still not so good as that on extraterrestrial radiation case. The irradiation data observed is much less than the data predicted by the empirical model, however the trend of fitting curve to the observed data is somewhat in agreement with that to the predicted one; the yearly gain is 14.3% when a tracked panel is employed throughout the year.

  18. New Temperature-based Models for Predicting Global Solar Radiation

    International Nuclear Information System (INIS)

    Hassan, Gasser E.; Youssef, M. Elsayed; Mohamed, Zahraa E.; Ali, Mohamed A.; Hanafy, Ahmed A.

    2016-01-01

    Highlights: • New temperature-based models for estimating solar radiation are investigated. • The models are validated against 20-years measured data of global solar radiation. • The new temperature-based model shows the best performance for coastal sites. • The new temperature-based model is more accurate than the sunshine-based models. • The new model is highly applicable with weather temperature forecast techniques. - Abstract: This study presents new ambient-temperature-based models for estimating global solar radiation as alternatives to the widely used sunshine-based models owing to the unavailability of sunshine data at all locations around the world. Seventeen new temperature-based models are established, validated and compared with other three models proposed in the literature (the Annandale, Allen and Goodin models) to estimate the monthly average daily global solar radiation on a horizontal surface. These models are developed using a 20-year measured dataset of global solar radiation for the case study location (Lat. 30°51′N and long. 29°34′E), and then, the general formulae of the newly suggested models are examined for ten different locations around Egypt. Moreover, the local formulae for the models are established and validated for two coastal locations where the general formulae give inaccurate predictions. Mostly common statistical errors are utilized to evaluate the performance of these models and identify the most accurate model. The obtained results show that the local formula for the most accurate new model provides good predictions for global solar radiation at different locations, especially at coastal sites. Moreover, the local and general formulas of the most accurate temperature-based model also perform better than the two most accurate sunshine-based models from the literature. The quick and accurate estimations of the global solar radiation using this approach can be employed in the design and evaluation of performance for

  19. Prediction of radiation-related small-bowel damage

    International Nuclear Information System (INIS)

    Potish, R.A.

    1980-01-01

    In order to predict which patients have a high risk for radiation-related small-bowel damage, the concept of the dose-response curve was applied to the predisposing factors (number of previous laparotomies, extent of surgery, thin physique, hypertension, age, cancer stage, number of treatment days, fractionation, and weight change during radiotherapy) present in 92 patients receiving identical radiation doses and volumes This analysis allows an estimate of the probability of complication to be assigned to individual patients. The utility and limitations of the dose-response concept are discussed

  20. Sound quality prediction for engine-radiated noise

    Science.gov (United States)

    Liu, Hai; Zhang, Junhong; Guo, Peng; Bi, Fengrong; Yu, Hanzhengnan; Ni, Guangjian

    2015-05-01

    Diesel engine-radiated noise quality prediction is an important topic because engine noise has a significant impact on the overall vehicle noise. Sound quality prediction is based on subjective and objective evaluation of engine noise. The integrated satisfaction index (ISI) is proposed as a criterion for differentiate noise quality in the subjective evaluation, and five psychoacoustic parameters are selected for characterizing and analyzing the noise quality of the diesel engine objectively. The combination of support vector machines (SVM) and genetic algorithm (GA) is proposed in order to establish a model for predicting the diesel engine-radiated noise quality for all operation conditions. The performance of the GA-SVM model is compared with the BP neural network model, and the results show that the mean relative error of the GA-SVM model is smaller than the BP neural network model. The importance rank of the sound quality metrics to the ISI is indicated by the non-parametric correlation analysis. This study suggests that the GA-SVM model is very useful for accurately predicting the diesel engine-radiated noise quality.

  1. Radiation hardness and precision timing study of silicon detectors for the CMS High Granularity Calorimeter (HGC)

    Energy Technology Data Exchange (ETDEWEB)

    Currás, Esteban, E-mail: ecurrasr@cern.ch [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Instituto de Física de Cantabria (CSIC-UC), Avda. los Castros s/n, E-39005 Santander (Spain); Fernández, Marcos [Instituto de Física de Cantabria (CSIC-UC), Avda. los Castros s/n, E-39005 Santander (Spain); Gallrapp, Christian [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Gray, Lindsey [Fermilab, Wilson Street and Kirk Road, Batavia, IL 60510-5011, Illinois (United States); Mannelli, Marcello [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Meridiani, Paolo [Istituto Nazionale Di Fisica Nucleare – Sezione di Roma, Piazzale Aldo Moro, 2, 00185 Roma (Italy); Moll, Michael [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Nourbakhsh, Shervin [University of Minnesota, Minneapolis, MN 55455 (United States); Scharf, Christian [Hamburg University, Notkestraße 85, 22607 Hamburg (Germany); Silva, Pedro [CERN, Organisation europnne pour la recherche nucleaire, CH-1211 Genéve 23 (Switzerland); Steinbrueck, Georg [Hamburg University, Notkestraße 85, 22607 Hamburg (Germany); Fatis, Tommaso Tabarelli de [Istituto Nazionale di Fisica Nucleare – Sezione di Milano-Bicocca Piazza della Scienza 3, 20126 Milano (Italy); Vila, Iván [Instituto de Física de Cantabria (CSIC-UC), Avda. los Castros s/n, E-39005 Santander (Spain)

    2017-02-11

    The high luminosity upgraded LHC or Phase-II is expected to increase the instantaneous luminosity by a factor of 10 beyond the LHC's design value, expecting to deliver 250 fb{sup −1} per year for a further 10 years of operation. Under these conditions the performance degradation due to integrated radiation dose will need to be addressed. The CMS collaboration is planning to upgrade the forward calorimeters. The replacement is called the High Granularity Calorimeter (HGC) and it will be realized as a sampling calorimeter with layers of silicon detectors interleaved. The sensors will be realized as pad detectors with sizes of less that ∼1.0 cm{sup 2} and an active thickness between 100 and 300 μm depending on the position, respectively, the expected radiation levels. For an integrated luminosity of 3000 fb{sup −1}, the electromagnetic calorimetry will sustain integrated doses of 1.5 MGy (150 Mrads) and neutron fluences up to 10{sup 16} neq/cm{sup 2}. A radiation tolerance study after neutron irradiation of 300, 200, and 100 μm n-on-p and p-on-n silicon pads irradiated to fluences up to 1.6×10{sup 16} neq/cm{sup 2} is presented. The properties of these diodes studied before and after irradiation were leakage current, capacitance, charge collection efficiency, annealing effects and timing capability. The results of these measurements validate these sensors as candidates for the HGC system.

  2. Generation of radicals in hard biological tissues under the action of laser radiation

    Science.gov (United States)

    Sviridov, Alexander P.; Bagratashvili, Victor N.; Sobol, Emil N.; Omelchenko, Alexander I.; Lunina, Elena V.; Zhitnev, Yurii N.; Markaryan, Galina L.; Lunin, Valerii V.

    2002-07-01

    The formation of radicals upon UV and IR laser irradiation of some biological tissues and their components was studied by the EPR technique. The radical decay kinetics in body tissue specimens after their irradiation with UV light were described by various models. By the spin trapping technique, it was shown that radicals were not produced during IR laser irradiation of cartilaginous tissue. A change in optical absorption spectra and the dynamics of optical density of cartilaginous tissue, fish scale, and a collagen film under exposure to laser radiation in an air, oxygen, and nitrogen atmosphere was studied.

  3. Cryogenic and radiation hard ASIC design for large format NIR/SWIR detector

    Science.gov (United States)

    Gao, Peng; Dupont, Benoit; Dierickx, Bart; Müller, Eric; Verbruggen, Geert; Gielis, Stijn; Valvekens, Ramses

    2014-10-01

    An ASIC is developed to control and data quantization for large format NIR/SWIR detector arrays. Both cryogenic and space radiation environment issue are considered during the design. Therefore it can be integrated in the cryogenic chamber, which reduces significantly the vast amount of long wires going in and out the cryogenic chamber, i.e. benefits EMI and noise concerns, as well as the power consumption of cooling system and interfacing circuits. In this paper, we will describe the development of this prototype ASIC for image sensor driving and signal processing as well as the testing in both room and cryogenic temperature.

  4. Radiation hardness evaluation of the commercial 150 nm CMOS process using 60Co source

    International Nuclear Information System (INIS)

    Carna, M; Havranek, M; Hejtmanek, M; Janoska, Z; Marcisovsky, M; Neue, G; Tomasek, L; Vrba, V

    2014-01-01

    We present a study of radiation effects on MOSFET transistors irradiated with a 60 Co source to a total absorbed dose of 1.5 Mrad. The transistor test structures were manufactured using a commercial 150 nm CMOS process and are composed of transistors of different types (NMOS and PMOS), dimensions and insulation from the bulk material by means of deep n-wells. We have observed a degradation of electrical characteristics of both PMOS and NMOS transistors, namely a large increase of the leakage current of the NMOS transistors after irradiation

  5. Application of gamma-gamma logging in predicting anomalous geodynamic phenomena in hard coal mines

    International Nuclear Information System (INIS)

    Blaha, F.; Keclik, L.

    1980-01-01

    The application is discussed of gamma-gamma logging in the prediction of dynamic events like coal and gas bursts, coal sliding in medium dip seams and rock bumps. The overall analysis of the applied rock characterization method and of the measurement results shows that the prediction possibilities of dynamic events are partly limited due to specific effects of the rock massive. In these cases, however, unambiguous results may be obtained by other geophysical methods such as seismoacoustic testing etc. In most cases, however, the gamma-gamma logging results may be used for estimating the degree of dynamic events or checking the efficiency of preventive measures in the locality under investigation. (author)

  6. Influence of Subjectivity in Geological Mapping on the Net Penetration Rate Prediction for a Hard Rock TBM

    Science.gov (United States)

    Seo, Yongbeom; Macias, Francisco Javier; Jakobsen, Pål Drevland; Bruland, Amund

    2018-05-01

    The net penetration rate of hard rock tunnel boring machines (TBM) is influenced by rock mass degree of fracturing. This influence is taken into account in the NTNU prediction model by the rock mass fracturing factor ( k s). k s is evaluated by geological mapping, the measurement of the orientation of fractures and the spacing of fractures and fracture type. Geological mapping is a subjective procedure. Mapping results can therefore contain considerable uncertainty. The mapping data of a tunnel mapped by three researchers were compared, and the influence of the variation in geological mapping was estimated to assess the influence of subjectivity in geological mapping. This study compares predicted net penetration rates and actual net penetration rates for TBM tunneling (from field data) and suggests mapping methods that can reduce the error related to subjectivity. The main findings of this paper are as follows: (1) variation of mapping data between individuals; (2) effect of observed variation on uncertainty in predicted net penetration rates; (3) influence of mapping methods on the difference between predicted and actual net penetration rate.

  7. Radiation hardness and precision timing study of Silicon Detectors for the CMS High Granularity Calorimeter (HGCAL)

    CERN Document Server

    Curras Rivera, Esteban

    2016-01-01

    The high luminosity LHC (HL-LHC or Phase-II) is expected to increase the instantaneous luminosity of the LHC by a factor of about five, delivering about 250 fba-1 per year between 2025 and 2035. Under these conditions the performance degradation of detectors due to integrated radiation dose/fluence will need to be addressed. The CMS collaboration is planning to upgrade many components, including the forward calorimeters. The replacement for the existing endcap preshower, electromagnetic and hadronic calorimeters is called the High Granularity Calorimeter (HGCAL) and it will be realized as a sampling calorimeter, including 30 layers of silicon detectors totalling 600m^2. The sensors will be realized as pad detectors with cell sizes of between 0.5-1.0 cm^2 and an active thickness between 100 um and 300 um depending on their location in the endcaps the thinner sensors will be used in the highest radiation environment. For an integrated luminosity of 3000 fba-1, the electromagnetic calorimetry will sustain integ...

  8. Development of radiation hard microstrip detectors for the CBM silicon tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Chatterji, Sudeep [GSI, Darmstadt (Germany)

    2010-07-01

    Radiation damage in Silicon microstrip detectors is of the one main concerns for the development of the Silicon Tracking System (STS) in the planned Compressed Baryonic Matter (CBM) experiment at FAIR. The STS will consist of Double Sided Silicon Strip Detectors (DSSD) having pitch around 60 {mu}m, width 20 {mu}m, stereo angle of {+-}7.5{sup 0} on n and p sides with double metallization on either side making it challenging to fabricate.We are using 3-dimensional TCAD simulation tools from SYNOPSYS to carry out process (using Sentaurus Process) and device (using Sentaurus Device) simulations.We have simulated the impact of radiation damage in DSSDs by changing the effective carrier concentration (N{sub eff}) with fluence using the Hamburg model. The change in minority carrier life time has been taken into account using the Kraners model and the Perugia trap model has been used to simulate the traps. We have also extracted macroscopic parameters like Coupling Capacitance, Interstrip Capacitance (both DC and AC), Interstrip Resistance of DSSDs using Mixed Mode simulation (using SPICE with Sentaurus Device) and studied the variation of these parameters with fluence. The simulation results have been compared to the experimental results. We also simulated transients by passing a Heavy Ion through a DSSD and studied the charge collection performance.

  9. A low power high speed radiation hard serializer for High Energy Physics experiments

    CERN Document Server

    AUTHOR|(CDS)2080243; Marchioro, Alessandro; Ottavi, Marco

    This Ph.D. thesis focuses on the development and the characterization of novel solutions for electronic systems for high-speed data transmission in extremely high radio-active environment (e.g. high energy physics application). The text proposes two alternative full-custom solutions for a fundamental enabling block for a lowpower serial data transmission system, the serializer. This block will find place in a future transceiver conceived for the future upgraded phase of the Large Hadron Collider, or LHC, at CERN. The first solution proposed, called “triple module redundancy”, is based on hardware redundancy, a well-known solution, to obtain protection against the temporary malfunctioning induced by radiation. In the second case a new architecture, called “code protected”, is proposed. This architecture takes advantage of the error correction code present in the data word to obtain radiation robustness on data and some parts of the control logic and to further reduce the power consumption. A test chip ...

  10. Technology development of p-type microstrip detectors with radiation hard p-spray isolation

    International Nuclear Information System (INIS)

    Pellegrini, G.; Fleta, C.; Campabadal, F.; Diez, S.; Lozano, M.; Rafi, J.M.; Ullan, M.

    2006-01-01

    A technology for the fabrication of p-type microstrip silicon radiation detectors using p-spray implant isolation has been developed at CNM-IMB. The p-spray isolation has been optimized in order to withstand a gamma irradiation dose up to 50 Mrad (Si), which represents the ionization radiation dose expected in the middle region of the SCT-Atlas detector of the future Super-LHC during 10 years of operation. The best technological options for the p-spray implant were found by using a simulation software package and dedicated calibration runs. Using the optimized technology, detectors have been fabricated in the Clean Room facility of CNM-IMB, and characterized by reverse current and capacitance measurements before and after irradiation. The average full depletion voltage measured on the non-irradiated detectors was V FD =41±3 V, while the leakage current density for the microstrip devices at V FD +20 V was 400 nA/cm 2

  11. Why Gender and Age Prediction from Tweets is Hard : Lessons from a Crowdsourcing Experiment

    NARCIS (Netherlands)

    Nguyen, D.; Trieschnigg, D.; Dogruöz, A. Seza; Gravel, Rilana; Theune, Mariët; Meder, Theo; de Jong, Franciska

    2014-01-01

    There is a growing interest in automatically predicting the gender and age of authors from texts. However, most research so far ignores that language use is related to the social identity of speakers, which may be different from their biological identity. In this paper, we combine insights from

  12. Why Gender and Age Prediction from Tweets is Hard: Lessons from a Crowdsourcing Experiment

    NARCIS (Netherlands)

    Nguyen, Dong-Phuong; Trieschnigg, Rudolf Berend; Dogruoz, A. Seza; Gravel, Rilana; Theune, Mariet; Meder, Theo; de Jong, Franciska M.G.

    2014-01-01

    There is a growing interest in automatically predicting the gender and age of authors from texts. However, most research so far ignores that language use is related to the social identity of speakers, which may be different from their biological identity. In this paper, we combine insights from

  13. Radiation hardness and timing studies of a monolithic TowerJazz pixel design for the new ATLAS Inner Tracker

    Science.gov (United States)

    Riegel, C.; Backhaus, M.; Van Hoorne, J. W.; Kugathasan, T.; Musa, L.; Pernegger, H.; Riedler, P.; Schaefer, D.; Snoeys, W.; Wagner, W.

    2017-01-01

    A part of the upcoming HL-LHC upgrade of the ATLAS Detector is the construction of a new Inner Tracker. This upgrade opens new possibilities, but also presents challenges in terms of occupancy and radiation tolerance. For the pixel detector inside the inner tracker, hybrid modules containing passive silicon sensors and connected readout chips are presently used, but require expensive assembly techniques like fine-pitch bump bonding. Silicon devices fabricated in standard commercial CMOS technologies, which include part or all of the readout chain, are also investigated offering a reduced cost as they are cheaper per unit area than traditional silicon detectors. If they contain the full readout chain, as for a fully monolithic approach, there is no need for the expensive flip-chip assembly, resulting in a further cost reduction and material savings. In the outer pixel layers of the ATLAS Inner Tracker, the pixel sensors must withstand non-ionising energy losses of up to 1015 n/cm2 and offer a timing resolution of 25 ns or less. This paper presents test results obtained on a monolithic test chip, the TowerJazz 180nm Investigator, towards these specifications. The presented program of radiation hardness and timing studies has been launched to investigate this technology's potential for the new ATLAS Inner Tracker.

  14. Radiation hardness and timing studies of a monolithic TowerJazz pixel design for the new ATLAS Inner Tracker

    International Nuclear Information System (INIS)

    Riegel, C.; Backhaus, M.; Hoorne, J.W. Van; Kugathasan, T.; Musa, L.; Pernegger, H.; Riedler, P.; Schaefer, D.; Snoeys, W.; Wagner, W.

    2017-01-01

    A part of the upcoming HL-LHC upgrade of the ATLAS Detector is the construction of a new Inner Tracker. This upgrade opens new possibilities, but also presents challenges in terms of occupancy and radiation tolerance. For the pixel detector inside the inner tracker, hybrid modules containing passive silicon sensors and connected readout chips are presently used, but require expensive assembly techniques like fine-pitch bump bonding. Silicon devices fabricated in standard commercial CMOS technologies, which include part or all of the readout chain, are also investigated offering a reduced cost as they are cheaper per unit area than traditional silicon detectors. If they contain the full readout chain, as for a fully monolithic approach, there is no need for the expensive flip-chip assembly, resulting in a further cost reduction and material savings. In the outer pixel layers of the ATLAS Inner Tracker, the pixel sensors must withstand non-ionising energy losses of up to 10 15 n/cm 2 and offer a timing resolution of 25 ns or less. This paper presents test results obtained on a monolithic test chip, the TowerJazz 180nm Investigator, towards these specifications. The presented program of radiation hardness and timing studies has been launched to investigate this technology's potential for the new ATLAS Inner Tracker.

  15. Radiation-hard Active Pixel Sensors for HL-LHC Detector Upgrades based on HV-CMOS Technology

    CERN Document Server

    Miucci, A; Hemperek, T.; Hügging, F.; Krüger, H.; Obermann, T.; Wermes, N.; Garcia-Sciveres, M.; Backhaus, M.; Capeans, M.; Feigl, S.; Nessi, M.; Pernegger, H.; Ristic, B.; Gonzalez-Sevilla, S.; Ferrere, D.; Iacobucci, G.; Rosa, A.La; Muenstermann, D.; George, M.; Grosse-Knetter, J.; Quadt, A.; Rieger, J.; Weingarten, J.; Bates, R.; Blue, A.; Buttar, C.; Hynds, D.; Kreidl, C.; Peric, I.; Breugnon, P.; Pangaud, P.; Godiot-Basolo, S.; Fougeron, D.; Bompard, F.; Clemens, J.C.; Liu, J; Barbero, M.; Rozanov, A

    2014-01-01

    Luminosity upgrades are discussed for the LHC (HL-LHC) which would make updates to the detectors necessary, requiring in particular new, even more radiation-hard and granular, sensors for the inner detector region. 1Corresponding author. c CERN 2014, published under the terms of the Creative Commons Attribution 3.0 License by IOP Publishing Ltd and Sissa Medialab srl. Any further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation and DOI. doi:10.1088/1748-0221/9/05/C050642014 JINST 9 C05064 A proposal for the next generation of inner detectors is based on HV-CMOS: a new family of silicon sensors based on commercial high-voltage CMOS technology, which enables the fabrication of part of the pixel electronics inside the silicon substrate itself. The main advantages of this technology with respect to the standard silicon sensor technology are: low material budget, fast charge collection time, high radiation tolerance, low cost and operation a...

  16. Radiation-hard Active Pixel Sensors for HL-LHC Detector Upgrades based on HV-CMOS Technology

    International Nuclear Information System (INIS)

    Miucci, A; Gonzalez-Sevilla, S; Ferrere, D; Iacobucci, G; Rosa, A La; Muenstermann, D; Gonella, L; Hemperek, T; Hügging, F; Krüger, H; Obermann, T; Wermes, N; Garcia-Sciveres, M; Backhaus, M; Capeans, M; Feigl, S; Nessi, M; Pernegger, H; Ristic, B; George, M

    2014-01-01

    Luminosity upgrades are discussed for the LHC (HL-LHC) which would make updates to the detectors necessary, requiring in particular new, even more radiation-hard and granular, sensors for the inner detector region. A proposal for the next generation of inner detectors is based on HV-CMOS: a new family of silicon sensors based on commercial high-voltage CMOS technology, which enables the fabrication of part of the pixel electronics inside the silicon substrate itself. The main advantages of this technology with respect to the standard silicon sensor technology are: low material budget, fast charge collection time, high radiation tolerance, low cost and operation at room temperature. A traditional readout chip is still needed to receive and organize the data from the active sensor and to handle high-level functionality such as trigger management. HV-CMOS has been designed to be compatible with both pixel and strip readout. In this paper an overview of HV2FEI4, a HV-CMOS prototype in 180 nm AMS technology, will be given. Preliminary results after neutron and X-ray irradiation are shown

  17. Ionization processes in the Fe 27 region of hot iron plasma in the field of hard gamma radiation

    International Nuclear Information System (INIS)

    Illarionov, A.F.

    1989-01-01

    A highly ionized hot plasma of an iron 26 56 Fe-type heavy element in the field of hard ionizing gamma-ray radiation is considered. The processes of ionization and recombination are discussed for a plasma consisting of the fully ionized Fe 27 and the hydrogen-like Fe 26 ions of iron in the case of large optical depth of the plasma with respect to the photoionization by gamma-ray quanta. The self-ionization process of a hot plasma with the temperature kT ≅ I (I being the ionization potential), due to the production of the own ionizing gamma-ray quanta, by the free-free (ff) and recombination (fb) radiation mechanisms, is investigated. It is noted that in the stationary situation the process of self-ionization of a hot plasma imposes the restriction upon the plasma temperature, kT<1.5 I. It is shown that the ionization of heavy-ion plasma by the impact of thermal electrons is dominating over the processes of ff- and fb-selfionization of plasma only by the large concentration of hydrogen-like iron at the periphery of the region of fully ionized iron Fe 27

  18. Standard Practice for Minimizing Dosimetry Errors in Radiation Hardness Testing of Silicon Electronic Devices Using Co-60 Sources

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice covers recommended procedures for the use of dosimeters, such as thermoluminescent dosimeters (TLD's), to determine the absorbed dose in a region of interest within an electronic device irradiated using a Co-60 source. Co-60 sources are commonly used for the absorbed dose testing of silicon electronic devices. Note 1—This absorbed-dose testing is sometimes called “total dose testing” to distinguish it from “dose rate testing.” Note 2—The effects of ionizing radiation on some types of electronic devices may depend on both the absorbed dose and the absorbed dose rate; that is, the effects may be different if the device is irradiated to the same absorbed-dose level at different absorbed-dose rates. Absorbed-dose rate effects are not covered in this practice but should be considered in radiation hardness testing. 1.2 The principal potential error for the measurement of absorbed dose in electronic devices arises from non-equilibrium energy deposition effects in the vicinity o...

  19. Effects of alpha radiation on hardness and toughness of the borosilicate glass applied to radioactive wastes immobilization

    International Nuclear Information System (INIS)

    Prado, Miguel Oscar; Bernasconi, Norma B. Messi de; Bevilacqua, Arturo Miguel; Arribere, Maria Angelica; Heredia, Arturo D.; Sanfilippo, Miguel

    1999-01-01

    Borosilicate german glass SG7 samples, obtained by frit sintering, were irradiated with different fluences of thermal neutrons in the nucleus of a nuclear reactor. The nuclear reaction 10 B(n,α) 7 Li, where the 10 B isotope is one of the natural glass components, was used to generate alpha particles throughout the glass volume. The maximum alpha disintegration per unit volume achieved was equivalent to that accumulated in a borosilicate glass with nuclear wastes after 3.8 million years. Through Vickers indentations values for microhardness, stress for 50% fracture probability (Weibull statistics) and estimation of the toughness were obtained as a function of alpha radiation dose. Two counterbalanced effects were found: that due to the disorder created by the alpha particles in the glass and that due to the annealing during irradiation (temperature below 240 deg C). Considering the alpha radiation effect, glasses tend decrease Vickers hardness, and to increase thr 50% fracture probability stress with the dose increase. (author)

  20. A measurement of Lorentz Angle of radiation-hard Pixel Sensors

    CERN Document Server

    Aleppo, M

    2001-01-01

    Silicon pixel detectors developed to meet LHC requirements were tested in a beam at CERN in the framework of the ATLAS collaboration. The experimental behaviour of irradiated and not-irradiated sensors in a magnetic field is discussed. The measurement of the Lorentz angle for these sensors at different operating conditions is presented. A simple model of the charge drift in silicon before and after irradiation is presented. The good agreement between the model predictions and the experimental results is shown.

  1. Predictive modeling of terrestrial radiation exposure from geologic materials

    Science.gov (United States)

    Haber, Daniel A.

    Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials in an area by creating a model using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low spatial resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas, referred to as background radiation units, homogenous in terms of K, U, and Th are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by our partner National Security Technologies, LLC (NSTec), allowing for the refinement of the technique. High resolution radiation exposure rate models have been developed for two study areas in Southern Nevada that include the alluvium on the western shore of Lake Mohave, and Government Wash north of Lake Mead; both of these areas are arid with little soil moisture and vegetation. We determined that by using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide radiation background units of alluvium, regions of homogeneous geochemistry can be defined allowing for the exposure rate to be predicted. Soil and rock samples have been collected at Government Wash and Lake Mohave as well as a third site near Cameron, Arizona. K, U, and Th concentrations of these samples have been determined using inductively coupled mass spectrometry (ICP-MS) and laboratory counting using radiation detection equipment. In addition, many sample locations also have

  2. Preparation and characterisation of radiation hard PbWO4 crystal scintillator

    International Nuclear Information System (INIS)

    Sabharwal, S.C.; Desai, D.G.; Sangeeta; Karandikar, S.C.; Chauhan, A.K.; Sangiri, A.K.; Keshwani, K.S.; Ahuja, M.N.

    1996-01-01

    The selective loss of one of the crystal constituents is found to be responsible for the yellowish coloration of PbWO 4 crystals. However, using the already pulled crystals as the starting charge for the subsequent growth, colorless crystals can be grown. The crystals exhibiting excellent transmission characteristics have been grown employing a low temperature gradient, a moderate rotation rate of 15 rpm and a pull speed of 1 mm/h. The colored crystals show some radiation damage on gamma irradiation, while the colorless ones remain unaffected even for irradiation doses as high as 10 Mrad. Both the types of crystals show the presence of weak thermoluminescence (TL) emission when high irradiation doses (similar 10 Mrad) are given. Only one TL glow peak is obtained in both the cases but the peak temperatures are different. The emission centers responsible for the TL emission are found to be the ones which give rise to the scintillation emission in the crystal. (orig.)

  3. Radiation hardness tests with a demonstrator preamplifier circuit manufactured in silicon on sapphire (SOS) VLSI technology

    International Nuclear Information System (INIS)

    Bingefors, N.; Ekeloef, T.; Eriksson, C.; Paulsson, M.; Moerk, G.; Sjoelund, A.

    1992-01-01

    Samples of the preamplifier circuit, as well as of separate n and p channel transistors of the type contained in the circuit, were irradiated with gammas from a 60 Co source up to an integrated dose of 3 Mrad (30 kGy). The VLSI manufacturing technology used is the SOS4 process of ABB Hafo. A first analysis of the tests shows that the performance of the amplifier remains practically unaffected by the radiation for total doses up to 1 Mrad. At higher doses up to 3 Mrad the circuit amplification factor decreases by a factor between 4 and 5 whereas the output noise level remains unchanged. It is argued that it may be possible to reduce the decrease in amplification factor in future by optimizing the amplifier circuit design further. (orig.)

  4. LHCb: The Performance and Radiation Hardness of the Outer Tracker Detector for LHCb

    CERN Multimedia

    Färber, C

    2012-01-01

    The LHC bexperiment is designed to study B-decays at the LHC. It is crucial to accurately and efficiently detect the charged decay particles in the high-density particle environment of the LHC. For this, the Outer Tracker (OT) has been constructed, consisting of 53,760 straw tubes, covering in total an area of 360 m2 of double layers. At the time of the conference, the detector will have operated under nominal LHC conditions for a period of about 2 years, corresponding to an integrated luminosity of approximately 2.5 fb$^{-1}$ . The performance of the detector will be discussed in terms of high voltage stability, noise rate, single hit efficiency and resolution. Finally, first results on the radiation tolerance of this sensitive gas detector will be shown, after having received a total dose corresponding to about 100 mC/cm in the hottest region.

  5. Non-isothermal kinetics model to predict accurate phase transformation and hardness of 22MnB5 boron steel

    Energy Technology Data Exchange (ETDEWEB)

    Bok, H.-H.; Kim, S.N.; Suh, D.W. [Graduate Institute of Ferrous Technology, POSTECH, San 31, Hyoja-dong, Nam-gu, Pohang, Gyeongsangbuk-do (Korea, Republic of); Barlat, F., E-mail: f.barlat@postech.ac.kr [Graduate Institute of Ferrous Technology, POSTECH, San 31, Hyoja-dong, Nam-gu, Pohang, Gyeongsangbuk-do (Korea, Republic of); Lee, M.-G., E-mail: myounglee@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Anam-dong, Seongbuk-gu, Seoul (Korea, Republic of)

    2015-02-25

    A non-isothermal phase transformation kinetics model obtained by modifying the well-known JMAK approach is proposed for application to a low carbon boron steel (22MnB5) sheet. In the modified kinetics model, the parameters are functions of both temperature and cooling rate, and can be identified by a numerical optimization method. Moreover, in this approach the transformation start and finish temperatures are variable instead of the constants that depend on chemical composition. These variable reference temperatures are determined from the measured CCT diagram using dilatation experiments. The kinetics model developed in this work captures the complex transformation behavior of the boron steel sheet sample accurately. In particular, the predicted hardness and phase fractions in the specimens subjected to a wide range of cooling rates were validated by experiments.

  6. A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

    Science.gov (United States)

    Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

    2011-01-01

    ultimately impact the surface of Europa after the mission is completed. The current JEO mission concept includes a range of instruments on the payload, to monitor dynamic phenomena (such as Io's volcanoes and Jupiters atmosphere), map the Jovian magnetosphere and its interactions with the Galilean satellites, and characterize water oceans beneath the ice shells of Europa and Ganymede. The payload includes a low mass (3.7 Kg) and low power (ASIC that resides very close to the thermopile linear array outputs. Both the thermopile array and the MCD ASIC will need to show full functionality within the harsh Jovian radiation environment, operating at cryogenic temperatures, typically 150 K to 170 K. In the following, a radiation mitigation strategy together with a low risk Radiation-Hardened-By-Design (RHBD) methodology using commercial foundry processes is given for the design and manufacture of a MCD ASIC that will meet this challenge.

  7. Characterisation and application of radiation hard sensors for LHC and ILC

    International Nuclear Information System (INIS)

    Novgorodova, Olga

    2013-11-01

    The Large Hadron Collider (LHC) currently in operation intends to explore particle physics on the TeV scale. The International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are being designed to measure the properties of particles discovered at the LHC with higher precision. Very forward detector systems at these machines are needed for the precise measurement of the luminosity and to approach full polar angle overage. In the current detector concepts for linear collider two electromagnetic calorimeters, Beam Calorimeter (BeamCal) and Luminosity Calorimeter (LumiCal), are foreseen. Both calorimeters are designed as sandwich calorimeters with tungsten absorber layers instrumented with finely segmented sensors. Due to a large amount of beamstrahlung remnants hitting BeamCal at the innermost radii, the sensors must withstand up to 1 MGy radiation dose per year. In this thesis two types of sensor materials were investigated: single crystal chemical vapour deposition diamonds (scCVDD) and gallium arsenide doped by chromium (GaAs:Cr). The very forward calorimeters ensure coverage for high energy electrons, positrons and photons down to very low polar angles. Within this thesis, simulation studies are presented for different beam parameters of the ILC. A new sensor segmentation was proposed to achieve better reconstruction efficiency of single high-energy electrons, positrons and photons on top of the beamstrahlung background. Only for a few years ago polycrystalline diamond sensors have been used for beam diagnostics in high-energy physics experiments. The Compact Muon Solenoid experiment, CMS, at the LHC is instrumented with several detectors for the Beam Conditions and Radiation Monitoring. The Fast Beam Conditions Monitor (BCM1F) is part of these systems. Here for the first time single crystal diamond sensors have been used. Eight detectors, comprising each a single crystal sensor and front-end electronics, are positioned around the beam pipe on both

  8. Characterisation and application of radiation hard sensors for LHC and ILC

    Energy Technology Data Exchange (ETDEWEB)

    Novgorodova, Olga

    2013-11-15

    The Large Hadron Collider (LHC) currently in operation intends to explore particle physics on the TeV scale. The International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are being designed to measure the properties of particles discovered at the LHC with higher precision. Very forward detector systems at these machines are needed for the precise measurement of the luminosity and to approach full polar angle overage. In the current detector concepts for linear collider two electromagnetic calorimeters, Beam Calorimeter (BeamCal) and Luminosity Calorimeter (LumiCal), are foreseen. Both calorimeters are designed as sandwich calorimeters with tungsten absorber layers instrumented with finely segmented sensors. Due to a large amount of beamstrahlung remnants hitting BeamCal at the innermost radii, the sensors must withstand up to 1 MGy radiation dose per year. In this thesis two types of sensor materials were investigated: single crystal chemical vapour deposition diamonds (scCVDD) and gallium arsenide doped by chromium (GaAs:Cr). The very forward calorimeters ensure coverage for high energy electrons, positrons and photons down to very low polar angles. Within this thesis, simulation studies are presented for different beam parameters of the ILC. A new sensor segmentation was proposed to achieve better reconstruction efficiency of single high-energy electrons, positrons and photons on top of the beamstrahlung background. Only for a few years ago polycrystalline diamond sensors have been used for beam diagnostics in high-energy physics experiments. The Compact Muon Solenoid experiment, CMS, at the LHC is instrumented with several detectors for the Beam Conditions and Radiation Monitoring. The Fast Beam Conditions Monitor (BCM1F) is part of these systems. Here for the first time single crystal diamond sensors have been used. Eight detectors, comprising each a single crystal sensor and front-end electronics, are positioned around the beam pipe on both

  9. Design of Si-photonic structures to evaluate their radiation hardness dependence on design parameters

    International Nuclear Information System (INIS)

    Zeiler, M.; Detraz, S.; Olantera, L.; Pezzullo, G.; El Nasr-Storey, S. Seif; Sigaud, C.; Soos, C.; Troska, J.; Vasey, F.

    2016-01-01

    Particle detectors for future experiments at the HL-LHC will require new optical data transmitters that can provide high data rates and be resistant against high levels of radiation. Furthermore, new design paths for future optical readout systems for HL-LHC could be opened if there was a possibility to integrate the optical components with their driving electronics and possibly also the silicon particle sensors themselves. All these functionalities could potentially be combined in the silicon photonics technology which currently receives a lot of attention for conventional optical link systems. Silicon photonic test chips were designed in order to assess the suitability of this technology for deployment in high-energy physics experiments. The chips contain custom-designed Mach-Zehnder modulators, pre-designed ''building-block'' modulators, photodiodes and various other passive test structures. The simulation and design flow of the custom designed Mach-Zehnder modulators and some first measurement results of the chips are presented

  10. Radiation hard 3D diamond sensors for vertex detectors at HL-LHC

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00336619; Quadt, Arnulf; Grosse-Knetter, Jörn; Weingarten, Jens

    Diamond is a good candidate to replace silicon as sensor material in the innermost layer of a tracking detector at HL-LHC, due to its high radiation tolerance. After particle fluences of $10^{16}\\,{\\rm protons/cm^2}$, diamond sensors are expected to achieve a higher signal to noise ratio than silicon. In order to use low grade polycrystalline diamonds as sensors, electrodes inside the diamond bulk, so called 3D electrodes, are produced. Typically, this kind of diamond material has a lower charge collection distance (CCD) than higher grade diamond, which results in a decreased signal amplitude. With 3D electrodes it is possible to achieve full charge collection even in samples with low CCDs by decoupling the spacing of the electrodes from the thickness of the diamond bulk. The electrodes are produced using a femtosecond laser, which changes the phase of the diamond material. The phase changed material is conductive and identified as nanocrystalline graphite using Raman spectroscopy. Due to a crater like struct...

  11. The GBTIA, a 5 Gbit/s Radiation-Hard Optical Receiver for the SLHC Upgrades

    CERN Document Server

    Menouni, M; Moreira, P

    2009-01-01

    The GigaBit Transceiver (GBT) is a high-speed optical transmission system currently under development for HEP applications. This system will implement bi-directional optical links to be used in the radiation environment of the Super LHC. The GigaBit Transimpedance Amplifier (GBTIA) is the front-end optical receiver of the GBT chip set. This paper presents the GBTIA, a 5 Gbit/s, fully differential, and highly sensitive optical receiver designed and implemented in a commercial 0.13 μm CMOS process. When connected to a PIN-diode, the GBTIA displays a sensitivity better than −19 dBm for a BER of 10−12. The differential output across an external 50 Ω load remains constant at 400 mVpp even for signals near the sensitivity limit. The chip achieves an overall transimpedance gain of 20 kΩ with a measured bandwidth of 4 GHz. The total power consumption of the chip is less than 120 mW and the chip die size is 0.75 mm x 1.25 mm. Irradiation testing of the chip shows no performance degradation after a dose rate of ...

  12. Investigation on the improved radiation hardness of silicon detectors with high oxygen concentration

    CERN Document Server

    Moll, Michael; Lindström, G

    2000-01-01

    We present an investigation on the influence of the oxygen concentration on radiation-induced changes in the effective doping concentration of silicon detectors. Diodes fabricated from silicon with interstitial oxygen content ranging from below 2*10/sup 14/ to 9*10/sup 17/ cm/sup -3/ have been irradiated with fast neutrons up to a fluence of 2*10/sup 15/ cm/sup -2/. Our main interest focused on the so-called stable damage component in the change of the effective doping concentration being of prime importance for the application of silicon detectors in high-energy physics experiments. We demonstrate, that with a high oxygen enrichment the donor removal is appreciably reduced, reaching a value of only 10601130f the initial doping concentration for [O/sub i/]=9*10/sup 17/ cm/sup -3/, while for normal detector grade material with [O/sub i/] below 5*10/sup 16/ cm /sup -3/ that value is 60-90Furthermore, we show that the fluence proportional introduction of stable acceptors is independent of the oxygen concentratio...

  13. Predicting reading ability in teenagers who are deaf or hard of hearing: A longitudinal analysis of language and reading.

    Science.gov (United States)

    Worsfold, Sarah; Mahon, Merle; Pimperton, Hannah; Stevenson, Jim; Kennedy, Colin

    2018-04-13

    Deaf and hard of hearing (D/HH) children and young people are known to show group-level deficits in spoken language and reading abilities relative to their hearing peers. However, there is little evidence on the longitudinal predictive relationships between language and reading in this population. To determine the extent to which differences in spoken language ability in childhood predict reading ability in D/HH adolescents. and procedures: Participants were drawn from a population-based cohort study and comprised 53 D/HH teenagers, who used spoken language, and a comparison group of 38 normally hearing teenagers. All had completed standardised measures of spoken language (expression and comprehension) and reading (accuracy and comprehension) at 6-10 and 13-19 years of age. and results: Forced entry stepwise regression showed that, after taking reading ability at age 8 years into account, language scores at age 8 years did not add significantly to the prediction of Reading Accuracy z-scores at age 17 years (change in R 2  = 0.01, p = .459) but did make a significant contribution to the prediction of Reading Comprehension z-scores at age 17 years (change in R 2  = 0.17, p skills in middle childhood predict reading comprehension ability in adolescence. Continued intervention to support language development beyond primary school has the potential to benefit reading comprehension and hence educational access for D/HH adolescents. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Radiation-induced gene expression in human subcutaneous fibroblasts is predictive of radiation-induced fibrosis

    DEFF Research Database (Denmark)

    Rødningen, Olaug Kristin; Børresen-Dale, Anne-Lise; Alsner, Jan

    2008-01-01

    BACKGROUND AND PURPOSE: Breast cancer patients show a large variation in normal tissue reactions after ionizing radiation (IR) therapy. One of the most common long-term adverse effects of ionizing radiotherapy is radiation-induced fibrosis (RIF), and several attempts have been made over the last...... years to develop predictive assays for RIF. Our aim was to identify basal and radiation-induced transcriptional profiles in fibroblasts from breast cancer patients that might be related to the individual risk of RIF in these patients. MATERIALS AND METHODS: Fibroblast cell lines from 31 individuals......-treated fibroblasts. Transcriptional differences in basal and radiation-induced gene expression profiles were investigated using 15K cDNA microarrays, and results analyzed by both SAM and PAM. RESULTS: Sixty differentially expressed genes were identified by applying SAM on 10 patients with the highest risk of RIF...

  15. Development and application of the analyzer-based imaging technique with hard synchrotron radiation

    International Nuclear Information System (INIS)

    Coan, P.

    2006-07-01

    The objective of this thesis is twofold: from one side the application of the analyser-based X-ray phase contrast imaging to study cartilage, bone and bone implants using ESRF synchrotron radiation sources and on the other to contribute to the development of the phase contrast techniques from the theoretical and experimental point of view. Several human samples have been studied in vitro using the analyser based imaging (ABI) technique. Examination included projection and computed tomography imaging and 3-dimensional volume rendering of hip, big toe and ankle articular joints. X-ray ABI images have been critically compared with those obtained with conventional techniques, including radiography, computed tomography, ultrasound, magnetic resonance and histology, the latter taken as gold standard. Results show that only ABI imaging was able to either visualize or correctly estimate the early pathological status of the cartilage. The status of the bone ingrowth in sheep implants have also been examined in vitro: ABI images permitted to correctly distinguish between good and incomplete bone healing. Pioneering in-vivo ABI on guinea pigs were also successfully performed, confirming the possible use of the technique to follow up the progression of joint diseases, the bone/metal ingrowth and the efficacy of drugs treatments. As part of the development of the phase contrast techniques, two objectives have been reached. First, it has been experimentally demonstrated for the first time that the ABI and the propagation based imaging (PBI) can be combined to create images with original features (hybrid imaging, HI). Secondly, it has been proposed and experimentally tested a new simplified set-up capable to produce images with properties similar to those obtained with the ABI technique or HI. Finally, both the ABI and the HI have been theoretically studied with an innovative, wave-based simulation program, which was able to correctly reproduce experimental results. (author)

  16. Dark Radiation predictions from general Large Volume Scenarios

    Science.gov (United States)

    Hebecker, Arthur; Mangat, Patrick; Rompineve, Fabrizio; Witkowski, Lukas T.

    2014-09-01

    Recent observations constrain the amount of Dark Radiation (Δ N eff ) and may even hint towards a non-zero value of Δ N eff . It is by now well-known that this puts stringent constraints on the sequestered Large Volume Scenario (LVS), i.e. on LVS realisations with the Standard Model at a singularity. We go beyond this setting by considering LVS models where SM fields are realised on 7-branes in the geometric regime. As we argue, this naturally goes together with high-scale supersymmetry. The abundance of Dark Radiation is determined by the competition between the decay of the lightest modulus to axions, to the SM Higgs and to gauge fields, and leads to strict constraints on these models. Nevertheless, these constructions can in principle meet current DR bounds due to decays into gauge bosons alone. Further, a rather robust prediction for a substantial amount of Dark Radiation can be made. This applies both to cases where the SM 4-cycles are stabilised by D-terms and are small `by accident', i.e. tuning, as well as to fibred models with the small cycles stabilised by loops. In these constructions the DR axion and the QCD axion are the same field and we require a tuning of the initial misalignment to avoid Dark Matter overproduction. Furthermore, we analyse a closely related setting where the SM lives at a singularity but couples to the volume modulus through flavour branes. We conclude that some of the most natural LVS settings with natural values of model parameters lead to Dark Radiation predictions just below the present observational limits. Barring a discovery, rather modest improvements of present Dark Radiation bounds can rule out many of these most simple and generic variants of the LVS.

  17. Predicted radiation environment of the Saturn baseline diode

    International Nuclear Information System (INIS)

    Halbleib, J.A.; Lee, J.R.

    1987-09-01

    Coupled electron/photon Monte Carlo radiation transport was used to predict the radiation environment of the Saturn accelerator for the baseline diode design. The x-ray output has been calculated, as well as energy deposition in CaF 2 thermoluminescent dosimetry and silicon. It is found that the design criteria for the radiation environment will be met and that approximately 10 kJ of x rays will be available for simulation experiments, if the diode provides a nominal beam of 2.0-MeV electrons for 20 ns with a peak current of 12.5 MA. The penalty in dose and x-ray output for operating below the nominal energy in order to obtain a softer spectrum is quantified. The penalty for using excessive electron equilibration in the standard packaging of the thermoluminescent dosimeters is shown to be negligible. An intrinsic lack of electron equilibration for silicon elements of components and subsystems is verified for Saturn environments, demonstrating the ambiguity of design criteria based on silicon deposition. Validation of an efficient next-event-estimator method for predicting energy deposition in equilibrated detectors/dosimetry is confirmed. Finally, direct-electron depositions in excess of 1 kJ/g are shown to be easily achievable. 34 refs., 30 figs

  18. Assertiveness expectancies: how hard people push depends on the consequences they predict.

    Science.gov (United States)

    Ames, Daniel R

    2008-12-01

    The present article seeks to explain varying levels of assertiveness in interpersonal conflict and negotiations with assertiveness expectancies, idiosyncratic predictions people make about the social and instrumental consequences of assertive behavior. This account complements motivation-based models of assertiveness and competitiveness, suggesting that individuals may possess the same social values (e.g., concern for relationships) but show dramatically different assertiveness due to different assumptions about behavioral consequences. Results clarify the form of assertiveness expectancies, namely that most people assume increasing assertiveness can yield positive social and instrumental benefits up to a point, beyond which benefits decline. However, people vary in how assertive this perceived optimal point is. These individual differences in expectancies are linked in 4 studies to assertiveness, including self-reported assertiveness, rated behavioral preferences in assorted interpersonal conflict scenarios, partner ratings of participants' behavior in a face-to-face dyadic negotiation, and work colleague ratings of participants' assertiveness in the workplace. In each case, the link between expectancies and behavior remained after controlling for values. The results suggest a place for expectancies alongside values in psychological models of interpersonal assertiveness.

  19. Study of fast electrons from hard-X radiation; Etude des electrons rapides a partir du rayonnement X-dur

    Energy Technology Data Exchange (ETDEWEB)

    Arslanbekov, R.

    1995-12-19

    The goal of this thesis is the study of fast electron dynamics by means of the hard X-ray diagnosis installed in TORE SUPRA and numerical simulations. Fast electrons are generated in the plasma in the presence of the injected lower hybrid (LH) waves. Two aspects are studied in detail: the lower hybrid wave propagation and absorption in a periodically perturbed media and 2-D Fokker-Planck modelling of the fast electron dynamics in the presence of the LH power. Ripple effects on lower hybrid wave propagation and absorption are investigated using the ray tracing technique. A cylindrical equilibrium is first studied and a strong modification of the ray dynamics is predicted. Calculations are carried out in a real toroidal geometry corresponding to TORE SUPRA. It is shown that the lack of toroidal axisymmetry of the magnetic field may result in a modification of the ray evolution even if the global ray evolution is governed by the larger poloidal inhomogeneity. Simulation of LH experiments are performed for TORE SUPRA tokamak which has a large magnetic ripple (7% at the plasma edge). By considering ripple perturbation in LH current drive simulations, a better agreement is found with experimental results, in particular with the hard-X spectra and the current density profiles. In the second part of the thesis, a 2-D modeling of the fast electron dynamics in the velocity phase space is considered, based on the 2-D relativistic electron Fokker-Planck equation. Electron distribution functions obtained are used to calculate non-thermal Bremsstrahlung emission for different TORE SUPRA shots in a wide range of experimental conditions. (J.S.). 168 refs., 93 figs., 1 tab., 3 appendix.

  20. Evaluation of radiation tolerance of FETs used for Astro-E2 hard X-ray detector (HXD-II)

    International Nuclear Information System (INIS)

    Itoh, Takeshi; Niko, Hisako; Kokubun, Motohide; Makishima, Kazuo; Kawaharada, Madoka; Takahashi, Isao; Miyasaka, Hiromasa

    2005-01-01

    We evaluated the radiation tolerance of three types of metal-can MOS Field Effect Transistors (FETs). They are candidates for flight electronics of the Hard X-ray Detector (HXD-II) experiment which is onboard the cosmic X-ray satellite Astro-E2 scheduled for launch in 2005. We irradiated FETs with a Co60γ-ray source under several different experimental conditions, and measured changes in their I-V characteristic curves. After a 10krad irradiation during which the gate voltage is set at 0V, all types showed a decrease in the switching voltage by ∼0.2-0.4V. In addition, the gate conductance increased under some irradiation conditions. These experimental results may be explained in terms of trapped charges and boundary levels in the oxide layer beneath the gate electrode. We have confirmed that at least two types of FETs can be used in our satellite-borne experiment, one as relay-driving FETs and the other in TTL-ECL conversion circuits

  1. Predictions of integrated circuit serviceability in space radiation fields

    Energy Technology Data Exchange (ETDEWEB)

    Khamidullina, N.M.; Kuznetsov, N.V.; Pichkhadze, K.M.; Popov, V.D

    1999-10-01

    The present paper suggests an approach to estimating and predicting the serviceability of on-board electronic equipment. It is based on the postulates of the reliability theory and accounts for total-dose and single-event radiation effects as well as other exterior destabilizing factors. The methods of determination of failure and upset rates for CMOS devices are considered. The probability of non-failure operation of a two CMOS RAM is calculated along the whole trajectory of the 'Solar Probe' spacecraft.

  2. Prediction of LDEF exposure to the ionizing radiation environment

    Science.gov (United States)

    Watts, J. W.; Armstrong, T. W.; Colborn, B. L.

    1996-01-01

    Predictions of the LDEF mission's trapped proton and electron and galactic cosmic ray proton exposures have been made using the currently accepted models with improved resolution near mission end and better modeling of solar cycle effects. An extension of previous calculations, to provide a more definitive description of the LDEF exposure to ionizing radiation, is represented by trapped proton and electron flux as a function of mission time, presented considering altitude and solar activity variation during the mission and the change in galactic cosmic ray proton flux over the mission. Modifications of the AP8MAX and AP8MIN fluence led to a reduction of fluence by 20%. A modified interpolation model developed by Daly and Evans resulted in 30% higher dose and activation levels, which better agreed with measured values than results predicted using the Vette model.

  3. Shelf life prediction of radiation sterilized polymeric materials

    International Nuclear Information System (INIS)

    Sandford, Craig; Woo, Lecon

    1988-01-01

    The functional properties of many polymers employed in medical disposables are unaffected by sterilizing doses of ionizing radiation. However, some materials (PVC, polypropylene, cellulosics, etc.) undergo undesirable changes which continue to occur for the shelf life of the product. In many cases, conventional accelerated aging techniques do not accurately predict the real time properties of the materials. As real time aging is not generally practical, it has become necessary to develop accelerated aging techniques which can predict the functional properties of a material for the shelf life of the product. This presentation will address issues involved in developing these tests. Real time physical property data is compared to data generated by various acceleration methods. (author)

  4. Influence of ionizing radiation on optical hardness of transparent dielectrics to action of huge intensity laser light

    International Nuclear Information System (INIS)

    Bedilov, M.R.; Khalilov, R.A.

    2006-01-01

    Full text: This paper presents results of researches of optical hardness of γ -irradiated with doze 10 4 - 10 9 rad alkali-silicate (K, GLS, LGS) and quartz (KU, KV, KSG) glasses against influence of radiation neodymium laser with intensity q = 0,1-1000 GWt/cm 2 . It is observed, that the laser produces damage of surface and volume of investigated glasses before and after γ-irradiation. This damage has threshold character and is always accompanied by a bright luminescence of plasma. Definition of threshold values of intensity superficial q s and volumetric q d laser produced damage was made by the complex method - fixing the moment of damage of transparent dielectric by simultaneous registration of the laser impulse which has passed through plasma of breakdown, mass-charge spectrum of ions of plasma and measuring the energy falling on the glass, and of penetrated and mirror-image radiations; and by optical microscopy. This method of research of influence γ-induced in transparent dielectric radiating defects on its optical stability against influence of laser radiation allows not only to define values q s and q d in the investigated interval of dozes, but also to investigate in details physical phenomena taking place in this process of interaction. On the basis of the received data quantitative characteristics of optical durability of the investigated glasses on wave length of λ1,06 microns depending on dozes of γ-irradiation and intensity of laser radiation are made. Doze dependences of charge and power spectra and quantitative characteristics of ions of plasma of breakdown were investigated at q≥ q s . In the investigated interval of dozes of γ- irradiation and intensity of laser radiation by a method of optical microscopy the morphology of occurring laser damage as surfaces, and volume of glass is also studied. It is found, that γ -induced defects in investigated glasses strongly effect on thresholds of damage q s and q d and on characteristics of ions

  5. Through a glass darkly: predicting the future of radiation oncology

    International Nuclear Information System (INIS)

    Peters, Lester J.

    1995-01-01

    To position ourselves professionally for the inevitable transition to managed care demands serious self-appraisal. Like most procedural medical specialties, radiation oncology is currently ill prepared for a capitated system of payment. To prosper under capitation, we need to increase the utility of radiation therapy per unit cost. This can be achieved by making the following adaptive responses: (a) we must ensure that the needs of medical practice drive the use of costly technology and not vice versa; (b) we must subordinate firmly held beliefs and prejudices to solid scientific data and be prepared to modify our practice when more cost-effective alternatives exist; and (c) we must be increasingly conscious of outcome, not process, in deciding among treatment options; and (d) we must acknowledge the need to prioritize the use of finite resources so that the maximum effort is expended on those who have the most to gain from treatment. These changes will permit us to develop guidelines for appropriate use of radiation therapy, and to demonstrate the excellent value of the service we can provide, which is the ultimate key to success. Though the future may at times seem bleak, we can shape it with our actions: the best way to predict the future is to create it

  6. Prediction of novel hard phases of Si{sub 3}N{sub 4}: First-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Lin; Hu, Meng; Wang, Qianqian; Xu, Bo; Yu, Dongli; Liu, Zhongyuan; He, Julong, E-mail: hjl@ysu.edu.cn

    2015-08-15

    Exploration of novel hard metastable phases of silicon nitride was performed using a recently developed particle-swarm optimization method within the CALYPSO software package. Three potential hard metastable phases of t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4} were predicted. These phases are mechanically and dynamically stable at ambient pressure based on their elastic constants and phonon dispersions. t-Si{sub 3}N{sub 4} and m-Si{sub 3}N{sub 4} exhibit lower energies than γ-Si{sub 3}N{sub 4} at pressures below 2.5 GPa and 2.9 GPa, respectively, which promise that the formers could be obtained by quenching from γ-Si{sub 3}N{sub 4}. o-Si{sub 3}N{sub 4} is a better high-pressure metastable phase than CaTi{sub 2}O{sub 4}-type Si{sub 3}N{sub 4} proposed by Tatsumi et al. and it can come from the transition of γ-Si{sub 3}N{sub 4} under 198 GPa. The theoretical band gaps of t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4} at ambient pressure were 3.15 eV, 3.90 eV, and 3.36 eV, respectively. At ambient pressure, the Vickers hardness values of t-Si{sub 3}N{sub 4} (32.6 GPa), m-Si{sub 3}N{sub 4} (31.5 GPa), and o-Si{sub 3}N{sub 4} (36.1 GPa) are comparable to β-Si{sub 3}N{sub 4} and γ-Si{sub 3}N{sub 4}. With the pressure increasing, t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4} will change from the brittle to ductile state at about 15.7 GPa, 7.3 GPa and 28.9 GPa, respectively. - Graphical abstract: This figure shows the crystal structures of three Si{sub 3}N{sub 4} predicted in this manuscript, and left to right: t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4} and o-Si{sub 3}N{sub 4}. - Highlights: • We explored three metastable phases of Si{sub 3}N{sub 4} — t-Si{sub 3}N{sub 4}, m-Si{sub 3}N{sub 4}, and o-Si{sub 3}N{sub 4}. • The enthalpies of t and m- are much lower than that of γ at ambient pressure. • ois one further high pressure phase than γ. • o-Si{sub 3}N{sub 4} is the most hardest phase in Si

  7. Predictive Biomarkers of Radiation Sensitivity in Rectal Cancer

    Science.gov (United States)

    Tut, Thein Ga

    Colorectal cancer (CRC) is the third most common cancer in the world. Australia, New Zealand, Canada, the United States, and parts of Europe have the highest incidence rates of CRC. China, India, South America and parts of Africa have the lowest risk of CRC. CRC is the second most common cancer in both sexes in Australia. Even though the death rates from CRC involving the colon have diminished, those arising from the rectum have revealed no improvement. The greatest obstacle in attaining a complete surgical resection of large rectal cancers is the close anatomical relation to surrounding structures, as opposed to the free serosal surfaces enfolding the colon. To assist complete resection, pre-operative radiotherapy (DXT) can be applied, but the efficacy of ionising radiation (IR) is extremely variable between individual tumours. Reliable predictive marker/s that enable patient stratification in the application of this otherwise toxic therapy is still not available. Current therapeutic management of rectal cancer can be improved with the availability of better predictive and prognostic biomarkers. Proteins such as Plk1, gammaH2AX and MMR proteins (MSH2, MSH6, MLH1 and PMS2), involved in DNA damage response (DDR) pathway may be possible biomarkers for radiation response prediction and prognostication of rectal cancer. Serine/threonine protein kinase Plk1 is overexpressed in most of cancers including CRC. Plk1 functional activity is essential in the restoration of DNA damage following IR, which causes DNA double strand break (DSB). The earliest manifestation of this reparative process is histone H2AX phosphorylation at serine 139, leading to gammaH2AX. Colorectal normal mucosa showed the lowest level of gammaH2AX with gradually increasing levels in early adenoma and then in advanced malignant colorectal tissues, leading to the possibility that gammaH2AX may be a prospective biomarker in rectal cancer management. There are numerous publications regarding DNA mismatch

  8. Numerical weather prediction (NWP) and hybrid ARMA/ANN model to predict global radiation

    International Nuclear Information System (INIS)

    Voyant, Cyril; Muselli, Marc; Paoli, Christophe; Nivet, Marie-Laure

    2012-01-01

    We propose in this paper an original technique to predict global radiation using a hybrid ARMA/ANN model and data issued from a numerical weather prediction model (NWP). We particularly look at the multi-layer perceptron (MLP). After optimizing our architecture with NWP and endogenous data previously made stationary and using an innovative pre-input layer selection method, we combined it to an ARMA model from a rule based on the analysis of hourly data series. This model has been used to forecast the hourly global radiation for five places in Mediterranean area. Our technique outperforms classical models for all the places. The nRMSE for our hybrid model MLP/ARMA is 14.9% compared to 26.2% for the naïve persistence predictor. Note that in the standalone ANN case the nRMSE is 18.4%. Finally, in order to discuss the reliability of the forecaster outputs, a complementary study concerning the confidence interval of each prediction is proposed. -- Highlights: ► Time series forecasting with hybrid method based on the use of ALADIN numerical weather model, ANN and ARMA. ► Innovative pre-input layer selection method. ► Combination of optimized MLP and ARMA model obtained from a rule based on the analysis of hourly data series. ► Stationarity process (method and control) for the global radiation time series.

  9. Prediction of the hardness profile of an AISI 4340 steel cylinder heat-treated by laser - 3D and artificial neural networks modelling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Hadhri, Mahdi; Ouafi, Abderazzak El; Barka, Noureddine [University of Quebec, Rimouski (Canada)

    2017-02-15

    This paper presents a comprehensive approach developed to design an effective prediction model for hardness profile in laser surface transformation hardening process. Based on finite element method and Artificial neural networks, the proposed approach is built progressively by (i) examining the laser hardening parameters and conditions known to have an influence on the hardened surface attributes through a structured experimental investigation, (ii) investigating the laser hardening parameters effects on the hardness profile through extensive 3D modeling and simulation efforts and (ii) integrating the hardening process parameters via neural network model for hardness profile prediction. The experimental validation conducted on AISI4340 steel using a commercial 3 kW Nd:Yag laser, confirm the feasibility and efficiency of the proposed approach leading to an accurate and reliable hardness profile prediction model. With a maximum relative error of about 10 % under various practical conditions, the predictive model can be considered as effective especially in the case of a relatively complex system such as laser surface transformation hardening process.

  10. Prediction of the hardness profile of an AISI 4340 steel cylinder heat-treated by laser - 3D and artificial neural networks modelling and experimental validation

    International Nuclear Information System (INIS)

    Hadhri, Mahdi; Ouafi, Abderazzak El; Barka, Noureddine

    2017-01-01

    This paper presents a comprehensive approach developed to design an effective prediction model for hardness profile in laser surface transformation hardening process. Based on finite element method and Artificial neural networks, the proposed approach is built progressively by (i) examining the laser hardening parameters and conditions known to have an influence on the hardened surface attributes through a structured experimental investigation, (ii) investigating the laser hardening parameters effects on the hardness profile through extensive 3D modeling and simulation efforts and (ii) integrating the hardening process parameters via neural network model for hardness profile prediction. The experimental validation conducted on AISI4340 steel using a commercial 3 kW Nd:Yag laser, confirm the feasibility and efficiency of the proposed approach leading to an accurate and reliable hardness profile prediction model. With a maximum relative error of about 10 % under various practical conditions, the predictive model can be considered as effective especially in the case of a relatively complex system such as laser surface transformation hardening process

  11. Immediate postoperative outcome of orthognathic surgical planning, and prediction of positional changes in hard and soft tissue, independently of the extent and direction of the surgical corrections required

    DEFF Research Database (Denmark)

    Donatsky, Ole; Bjørn-Jørgensen, Jens; Hermund, Niels Ulrich

    2011-01-01

    orthognathic correction using the computerised, cephalometric, orthognathic, surgical planning system (TIOPS). Preoperative cephalograms were analysed and treatment plans and prediction tracings produced by computerised interactive simulation. The planned changes were transferred to models and finally...... with the presently included soft tissue algorithms, the current study shows relatively high mean predictability of the immediately postoperative hard and soft tissue outcome, independent of the extent and direction of required orthognathic correction. Because of the relatively high individual variability, caution...

  12. A nonlinear support vector machine model with hard penalty function based on glowworm swarm optimization for forecasting daily global solar radiation

    International Nuclear Information System (INIS)

    Jiang, He; Dong, Yao

    2016-01-01

    Highlights: • Eclat data mining algorithm is used to determine the possible predictors. • Support vector machine is converted into a ridge regularization problem. • Hard penalty selects the number of radial basis functions to simply the structure. • Glowworm swarm optimization is utilized to determine the optimal parameters. - Abstract: For a portion of the power which is generated by grid connected photovoltaic installations, an effective solar irradiation forecasting approach must be crucial to ensure the quality and the security of power grid. This paper develops and investigates a novel model to forecast 30 daily global solar radiation at four given locations of the United States. Eclat data mining algorithm is first presented to discover association rules between solar radiation and several meteorological factors laying a theoretical foundation for these correlative factors as input vectors. An effective and innovative intelligent optimization model based on nonlinear support vector machine and hard penalty function is proposed to forecast solar radiation by converting support vector machine into a regularization problem with ridge penalty, adding a hard penalty function to select the number of radial basis functions, and using glowworm swarm optimization algorithm to determine the optimal parameters of the model. In order to illustrate our validity of the proposed method, the datasets at four sites of the United States are split to into training data and test data, separately. The experiment results reveal that the proposed model delivers the best forecasting performances comparing with other competitors.

  13. Radiation hard detectors from silicon enriched with both oxygen and thermal donors improvements in donor removal and long-term stability with regard to neutron irradiation

    CERN Document Server

    Li, Z; Eremin, V; Dezillie, B; Chen, W; Bruzzi, M

    2002-01-01

    Detectors made on the silicon wafers with high concentration of thermal donors (TD), which were introduced during the high temperature long time (HTLT) oxygenation procedure, have been investigated in the study of radiation hardness with regard to neutron irradiation and donor removal problems in irradiated high resistivity Si detectors. Two facts have been established as the evidence of radiation hardness improvement of HTLT(TD) Si detectors irradiated below approx 10 sup 1 sup 4 n/cm sup 2 compared to detectors made on standard silicon wafers: the increase of space charge sign inversion fluence (of 1 MeV neutrons) due to lower initial Si resistivity dominated by TD, and the gain in the reverse annealing time constant tau favourable for this material. Coupled with extremely high radiation tolerance to protons observed earlier ('beta zero' behaviour in a wide range of fluence), detectors from HTLT(TD) Si may be unique for application in the experiments with multiple radiations. The changes in the effective sp...

  14. Predicting Radiation Pneumonitis After Stereotactic Ablative Radiation Therapy in Patients Previously Treated With Conventional Thoracic Radiation Therapy

    International Nuclear Information System (INIS)

    Liu Hui; Zhang Xu; Vinogradskiy, Yevgeniy Y.; Swisher, Stephen G.; Komaki, Ritsuko; Chang, Joe Y.

    2012-01-01

    Purpose: To determine the incidence of and risk factors for radiation pneumonitis (RP) after stereotactic ablative radiation therapy (SABR) to the lung in patients who had previously undergone conventional thoracic radiation therapy. Methods and Materials: Seventy-two patients who had previously received conventionally fractionated radiation therapy to the thorax were treated with SABR (50 Gy in 4 fractions) for recurrent disease or secondary parenchymal lung cancer (T 10 and mean lung dose (MLD) of the previous plan and the V 10 -V 40 and MLD of the composite plan were also related to RP. Multivariate analysis revealed that ECOG PS scores of 2-3 before SABR (P=.009), FEV1 ≤65% before SABR (P=.012), V 20 ≥30% of the composite plan (P=.021), and an initial PTV in the bilateral mediastinum (P=.025) were all associated with RP. Conclusions: We found that severe RP was relatively common, occurring in 20.8% of patients, and could be predicted by an ECOG PS score of 2-3, an FEV1 ≤65%, a previous PTV spanning the bilateral mediastinum, and V 20 ≥30% on composite (previous RT+SABR) plans. Prospective studies are needed to validate these predictors and the scoring system on which they are based.

  15. Accompanying of parameters of color, gloss and hardness on polymeric films coated with pigmented inks cured by different radiation doses of ultraviolet light

    International Nuclear Information System (INIS)

    Gonçalves Bardi, Marcelo Augusto; Brocardo Machado, Luci Diva

    2012-01-01

    In the search for alternatives to traditional paint systems solvent-based, the curing process of polymer coatings by ultraviolet light (UV) has been widely studied and discussed, especially because of their high content of solids and null emission of VOC. In UV-curing technology, organic solvents are replaced by reactive diluents, such as monomers. This paper aims to investigate variations on color, gloss and hardness of print inks cured by different UV radiation doses. The ratio pigment/clear coating was kept constant. The clear coating presented higher average values for König hardness than pigmented ones, indicating that UV-light absorption has been reduced by the presence of pigments. Besides, they have indicated a slight variation in function of cure degree for the studied radiation doses range. The gloss loss related to UV light exposition allows inferring that some degradation occurred at the surface of print ink films. - Highlights: ► Color, gloss and hardness are directly influenced by the different pigments. ► Clear coating analysis indicates reduction on UV-light absorption. ► Color and gloss indices indicated aeration in function of cure degree.

  16. Predicted effects of countermeasures on radiation doses from contaminated food

    International Nuclear Information System (INIS)

    Yamamoto, Hideaki; Nielsen, S.P.; Nielsen, F.

    1993-02-01

    Quantitative assessments of the effects on radiation-dose reductions from nine typical countermeasures against accidental fod contamination have been carried out with dynamic radioecological models. The foodstuffs are assumed to be contaminated with iodine-131, caesium-134 and caesium-137 after a release of radioactive materials from the Ringhals nuclear power station in Sweden resulting from a hypothetical core melt accident. The release of activity of these radionuclides is assumed at 0.07% of the core inventory of the unit 1 reactor (1600 TBq of I-131, 220 TBq of Cs-134 and 190 TBq of Cs-137). Radiation doses are estimated for the 55,000 affected inhabitants along the south-eastern coast of Sweden eating locally produced foodstuffs. The average effective dose equivalent to an individual in the critical group is predicted to be 2.9 mSv from food consumption contaminated with I-131. An accident occurring during winter is estimated to cause average individual doses of 0.32 mSv from Cs-134 and 0.47 mSv from Cs-137, and 9.4 mSv and 6.8 mSv from Cs-134 and Cs-137, respectively, for an accident occurring during summer. Doses from the intake of radioiodine may be reduced by up to a factor of 60 by rejecting contaminated food for 30 days. For the doses from radiocaesium, the largest effect is found form deep ploughing which may reduce the dose by up to a factor of 80. (au) (12 tabs., 6 ills., 19 refs.)

  17. Developments for radiation hard silicon detectors by defect engineering - results by the CERN RD48 (ROSE) Collaboration

    International Nuclear Information System (INIS)

    Lindstroem, G.; Ahmed, M.; Albergo, S.; Allport, P.; Anderson, D.; Andricek, L.; Angarano, M.M.; Augelli, V.; Bacchetta, N.; Bartalini, P.; Bates, R.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Borchi, E.; Botila, T.; Brodbeck, T.J.; Bruzzi, M.; Budzynski, T.; Burger, P.; Campabadal, F.; Casse, G.; Catacchini, E.; Chilingarov, A.; Ciampolini, P.; Cindro, V.; Costa, M.J.; Creanza, D.; Clauws, P.; Da Via, C.; Davies, G.; De Boer, W.; Dell'Orso, R.; De Palma, M.; Dezillie, B.; Eremin, V.; Evrard, O.; Fallica, G.; Fanourakis, G.; Feick, H.; Focardi, E.; Fonseca, L.; Fretwurst, E.; Fuster, J.; Gabathuler, K.; Glaser, M.; Grabiec, P.; Grigoriev, E.; Hall, G.; Hanlon, M.; Hauler, F.; Heising, S.; Holmes-Siedle, A.; Horisberger, R.; Hughes, G.; Huhtinen, M.; Ilyashenko, I.; Ivanov, A.; Jones, B.K.; Jungermann, L.; Kaminsky, A.; Kohout, Z.; Kramberger, G.; Kuhnke, M.; Kwan, S.; Lemeilleur, F.; Leroy, C.; Letheren, M.; Li, Z.; Ligonzo, T.; Linhart, V.; Litovchenko, P.; Loukas, D.; Lozano, M.; Luczynski, Z.; Lutz, G.; MacEvoy, B.; Manolopoulos, S.; Markou, A.; Martinez, C.; Messineo, A.; Miku, M.; Moll, M.; Nossarzewska, E.; Ottaviani, G.; Oshea, V.; Parrini, G.; Passeri, D.; Petre, D.; Pickford, A.; Pintilie, I.; Pintilie, L.; Pospisil, S.; Potenza, R.; Radicci, V.; Raine, C.; Rafi, J.M.; Ratoff, P.N.; Richter, R.H.; Riedler, P.; Roe, S.; Roy, P.; Ruzin, A.; Ryazanov, A.I.; Santocchia, A.; Schiavulli, L.; Sicho, P.; Siotis, I.; Sloan, T.; Slysz, W.; Smith, K.; Solanky, M.; Sopko, B.; Stolze, K.; Sundby Avset, B.; Svensson, B.; Tivarus, C.; Tonelli, G.; Tricomi, A.; Tzamarias, S.; Valvo, G.; Vasilescu, A.; Vayaki, A.; Verbitskaya, E.; Verdini, P.; Vrba, V.; Watts, S.; Weber, E.R.; Wegrzecki, M.; Wegrzecka, I.; Weilhammer, P.; Wheadon, R.; Wilburn, C.; Wilhelm, I.; Wunstorf, R.; Wuestenfeld, J.; Wyss, J.; Zankel, K.; Zabierowski, P.; Zontar, D.

    2001-01-01

    This report summarises the final results obtained by the RD48 collaboration. The emphasis is on the more practical aspects directly relevant for LHC applications. The report is based on the comprehensive survey given in the 1999 status report (RD48 3rd Status Report, CERN/LHCC 2000-009, December 1999), a recent conference report (Lindstroem et al. (RD48), and some latest experimental results. Additional data have been reported in the last ROSE workshop (5th ROSE workshop, CERN, CERN/LEB 2000-005). A compilation of all RD48 internal reports and a full publication list can be found on the RD48 homepage (http://cern.ch/RD48/). The success of the oxygen enrichment of FZ-silicon as a highly powerful defect engineering technique and its optimisation with various commercial manufacturers are reported. The focus is on the changes of the effective doping concentration (depletion voltage). The RD48 model for the dependence of radiation effects on fluence, temperature and operational time is verified; projections to operational scenarios for main LHC experiments demonstrate vital benefits. Progress in the microscopic understanding of damage effects as well as the application of defect kinetics models and device modelling for the prediction of the macroscopic behaviour has also been achieved but will not be covered in detail

  18. High resolution hard X-ray photoemission using synchrotron radiation as an essential tool for characterization of thin solid films

    International Nuclear Information System (INIS)

    Kim, J.J.; Ikenaga, E.; Kobata, M.; Takeuchi, A.; Awaji, M.; Makino, H.; Chen, P.P.; Yamamoto, A.; Matsuoka, T.; Miwa, D.; Nishino, Y.; Yamamoto, T.; Yao, T.; Kobayashi, K.

    2006-01-01

    Recently, we have shown that hard X-ray photoemission spectroscopy using undulator X-rays at SPring-8 is quite feasible with both high resolution and high throughput. Here we report an application of hard X-ray photoemission spectroscopy to the characterization of electronic and chemical states of thin solid films, for which conventional PES is not applicable. As a typical example, we focus on the problem of the scatter in the reported band-gap values for InN. We show that oxygen incorporation into the InN film strongly modifies the valence and plays a crucial role in the band gap problem. The present results demonstrate the powerful applicability of high resolution photoemission spectroscopy with hard X-rays from a synchrotron source

  19. Predictions of space radiation fatality risk for exploration missions.

    Science.gov (United States)

    Cucinotta, Francis A; To, Khiet; Cacao, Eliedonna

    2017-05-01

    In this paper we describe revisions to the NASA Space Cancer Risk (NSCR) model focusing on updates to probability distribution functions (PDF) representing the uncertainties in the radiation quality factor (QF) model parameters and the dose and dose-rate reduction effectiveness factor (DDREF). We integrate recent heavy ion data on liver, colorectal, intestinal, lung, and Harderian gland tumors with other data from fission neutron experiments into the model analysis. In an earlier work we introduced distinct QFs for leukemia and solid cancer risk predictions, and here we consider liver cancer risks separately because of the higher RBE's reported in mouse experiments compared to other tumors types, and distinct risk factors for liver cancer for astronauts compared to the U.S. The revised model is used to make predictions of fatal cancer and circulatory disease risks for 1-year deep space and International Space Station (ISS) missions, and a 940 day Mars mission. We analyzed the contribution of the various model parameter uncertainties to the overall uncertainty, which shows that the uncertainties in relative biological effectiveness (RBE) factors at high LET due to statistical uncertainties and differences across tissue types and mouse strains are the dominant uncertainty. NASA's exposure limits are approached or exceeded for each mission scenario considered. Two main conclusions are made: 1) Reducing the current estimate of about a 3-fold uncertainty to a 2-fold or lower uncertainty will require much more expansive animal carcinogenesis studies in order to reduce statistical uncertainties and understand tissue, sex and genetic variations. 2) Alternative model assumptions such as non-targeted effects, increased tumor lethality and decreased latency at high LET, and non-cancer mortality risks from circulatory diseases could significantly increase risk estimates to several times higher than the NASA limits. Copyright © 2017 The Committee on Space Research (COSPAR

  20. Models for prediction of global solar radiation on horizontal surface ...

    African Journals Online (AJOL)

    The estimation of global solar radiation continues to play a fundamental role in solar engineering systems and applications. This paper compares various models for estimating the average monthly global solar radiation on horizontal surface for Akure, Nigeria, using solar radiation and sunshine duration data covering years ...

  1. A proposed hardness assurance test methodology for bipolar linear circuits and devices in a space ionizing radiation environment

    International Nuclear Information System (INIS)

    Pease, R.L.; Brown, D.B.; Cohn, L.

    1997-01-01

    A hardness assurance test approach has been developed for bipolar linear circuits and devices in space. It consists of a screen for dose rate sensitivity and a characterization test method to develop the conditions for a lot acceptance test at high dose rate

  2. Comparison of observed rheological properties of hard wheat flour dough with predictions of the Giesekus-Leonov, White-Metzner and Phan-Thien Tanner models

    Science.gov (United States)

    Dhanasekharan, M.; Huang, H.; Kokini, J. L.; Janes, H. W. (Principal Investigator)

    1999-01-01

    The measured rheological behavior of hard wheat flour dough was predicted using three nonlinear differential viscoelastic models. The Phan-Thien Tanner model gave good zero shear viscosity prediction, but overpredicted the shear viscosity at higher shear rates and the transient and extensional properties. The Giesekus-Leonov model gave similar predictions to the Phan-Thien Tanner model, but the extensional viscosity prediction showed extension thickening. Using high values of the mobility factor, extension thinning behavior was observed but the predictions were not satisfactory. The White-Metzner model gave good predictions of the steady shear viscosity and the first normal stress coefficient but it was unable to predict the uniaxial extensional viscosity as it exhibited asymptotic behavior in the tested extensional rates. It also predicted the transient shear properties with moderate accuracy in the transient phase, but very well at higher times, compared to the Phan-Thien Tanner model and the Giesekus-Leonov model. None of the models predicted all observed data consistently well. Overall the White-Metzner model appeared to make the best predictions of all the observed data.

  3. A pixel unit-cell targeting 16ns resolution and radiation hardness in a column read-out particle vertex detector

    International Nuclear Information System (INIS)

    Wright, M.; Millaud, J.; Nygren, D.

    1993-01-01

    A pixel unit cell (PUC) circuit architecture, optimized for a column read out architecture, is reported. Each PUC contains an integrator, active filter, comparator, and optional analog store. The time-over-threshold (TOT) discriminator allows an all-digital interface to the array periphery readout while passing an analog measure of collected charge. Use of (existing) radiation hard processes, to build a detector bump-bonded to a pixel readout array, is targeted. Here emphasis is on a qualitative explanation of how the unique circuit implementation benefits operation for Super Collider (SSC) detector application. (orig.)

  4. A pixel unit-cell targeting 16 ns resolution and radiation hardness in a column read-out particle vertex detector

    International Nuclear Information System (INIS)

    Wright, M.; Millaud, J.; Nygren, D.

    1992-10-01

    A pixel unit cell (PUC) circuit architecture, optimized for a column read out architecture, is reported. Each PUC contains an integrator, active filter, comparator, and optional analog store. The time-over-threshold (TOT) discriminator allows an all-digital interface to the array periphery readout while passing an analog measure of collected charge. Use of (existing) radiation hard processes, to build a detector bump-bonded to a pixel readout array, is targeted. Here, emphasis is on a qualitative explanation of how the unique circuit implementation benefits operation for Super Collider (SSC) detector application

  5. Statistical experiments using the multiple regression research for prediction of proper hardness in areas of phosphorus cast-iron brake shoes manufacturing

    Science.gov (United States)

    Kiss, I.; Cioată, V. G.; Ratiu, S. A.; Rackov, M.; Penčić, M.

    2018-01-01

    Multivariate research is important in areas of cast-iron brake shoes manufacturing, because many variables interact with each other simultaneously. This article focuses on expressing the multiple linear regression model related to the hardness assurance by the chemical composition of the phosphorous cast irons destined to the brake shoes, having in view that the regression coefficients will illustrate the unrelated contributions of each independent variable towards predicting the dependent variable. In order to settle the multiple correlations between the hardness of the cast-iron brake shoes, and their chemical compositions several regression equations has been proposed. Is searched a mathematical solution which can determine the optimum chemical composition for the hardness desirable values. Starting from the above-mentioned affirmations two new statistical experiments are effectuated related to the values of Phosphorus [P], Manganese [Mn] and Silicon [Si]. Therefore, the regression equations, which describe the mathematical dependency between the above-mentioned elements and the hardness, are determined. As result, several correlation charts will be revealed.

  6. Impact of natural organic matter and increased water hardness on DGT prediction of copper bioaccumulation by yellow lampmussel (Lampsilis cariosa) and fathead minnow (Pimephales promelas).

    Science.gov (United States)

    Philipps, Rebecca R; Xu, Xiaoyu; Mills, Gary L; Bringolf, Robert B

    2018-06-01

    We conducted an exposure experiment with Diffusive Gradients in Thin- Films (DGT), fathead minnow (Pimephales promelas), and yellow lampmussel (Lampsilis cariosa) to estimate bioavailability and bioaccumulation of Cu. We hypothesized that Cu concentrations measured by DGT can be used to predict Cu accumulation in aquatic animals and alterations of water chemistry can affect DGT's predict ability. Three water chemistries (control soft water, hard water, and addition of natural organic matter (NOM)) and three Cu concentrations (0, 30, and 60 μg/L) were selected, so nine Cu-water chemistry combinations were used. NOM addition treatments resulted in decreased concentrations of DGT-measured Cu and free Cu ion predicted by Biotic Ligand Model (BLM). Both hard water and NOM addition treatments had reduced concentrations of Cu ion and Cu-dissolved organic matter complexes compared to other treatments. DGT-measured Cu concentrations were linearly correlated to fish accumulated Cu, but not to mussel accumulated Cu. Concentrations of bioavailable Cu predicted by BLM, the species complexed with biotic ligands of aquatic organisms and, was highly correlated to DGT-measured Cu. In general, DGT-measured Cu fit Cu accumulations in fish, and this passive sampling technique is acceptable at predicting Cu concentrations in fish in waters with low NOM concentrations. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Prediction of hardness for Al-Cu-Zn alloys in as-cast and quenching conditions; Prediccion de la dureza de aleaciones Al-Cu-Zn en estado de colada y templado

    Energy Technology Data Exchange (ETDEWEB)

    Villegas-Cardenas, J. D.; Saucedo-Munoz, M. L.; Lopez-Hirata, V. M.; Dorantes Rosales, H. J.

    2014-10-01

    This work presents a new experimental and numerical methodology in order to predict the hardness in the as-cast, and solution treated and quenched Al-Cu-Zn alloys. Chemical composition of alloys is located inside two straight lines represented by two equations. Eight different compositions were selected from each line. All the alloys were characterized for light microscope, scanning electron microscope, X-ray diffraction and Rockwell B hardness test. The equilibrium phases were obtained at different temperatures by Thermo-Calc. The microstructure characterization and regression analysis enabled to determine the phase transformations and two equations of hardness assessment. The combination of hardness equations and composition line equations permitted to estimate the hardness of any alloy composition inside this zone. This was verified by calculating hardness with the information reported in other works, with an error lower than 7% in the estimated hardness. (Author)

  8. Can radiation therapy treatment planning system accurately predict surface doses in postmastectomy radiation therapy patients?

    International Nuclear Information System (INIS)

    Wong, Sharon; Back, Michael; Tan, Poh Wee; Lee, Khai Mun; Baggarley, Shaun; Lu, Jaide Jay

    2012-01-01

    Skin doses have been an important factor in the dose prescription for breast radiotherapy. Recent advances in radiotherapy treatment techniques, such as intensity-modulated radiation therapy (IMRT) and new treatment schemes such as hypofractionated breast therapy have made the precise determination of the surface dose necessary. Detailed information of the dose at various depths of the skin is also critical in designing new treatment strategies. The purpose of this work was to assess the accuracy of surface dose calculation by a clinically used treatment planning system and those measured by thermoluminescence dosimeters (TLDs) in a customized chest wall phantom. This study involved the construction of a chest wall phantom for skin dose assessment. Seven TLDs were distributed throughout each right chest wall phantom to give adequate representation of measured radiation doses. Point doses from the CMS Xio® treatment planning system (TPS) were calculated for each relevant TLD positions and results correlated. There were no significant difference between measured absorbed dose by TLD and calculated doses by the TPS (p > 0.05 (1-tailed). Dose accuracy of up to 2.21% was found. The deviations from the calculated absorbed doses were overall larger (3.4%) when wedges and bolus were used. 3D radiotherapy TPS is a useful and accurate tool to assess the accuracy of surface dose. Our studies have shown that radiation treatment accuracy expressed as a comparison between calculated doses (by TPS) and measured doses (by TLD dosimetry) can be accurately predicted for tangential treatment of the chest wall after mastectomy.

  9. Sensitivity analysis of numerical weather prediction radiative schemes to forecast direct solar radiation over Australia

    Science.gov (United States)

    Mukkavilli, S. K.; Kay, M. J.; Taylor, R.; Prasad, A. A.; Troccoli, A.

    2014-12-01

    The Australian Solar Energy Forecasting System (ASEFS) project requires forecasting timeframes which range from nowcasting to long-term forecasts (minutes to two years). As concentrating solar power (CSP) plant operators are one of the key stakeholders in the national energy market, research and development enhancements for direct normal irradiance (DNI) forecasts is a major subtask. This project involves comparing different radiative scheme codes to improve day ahead DNI forecasts on the national supercomputing infrastructure running mesoscale simulations on NOAA's Weather Research & Forecast (WRF) model. ASEFS also requires aerosol data fusion for improving accurate representation of spatio-temporally variable atmospheric aerosols to reduce DNI bias error in clear sky conditions over southern Queensland & New South Wales where solar power is vulnerable to uncertainities from frequent aerosol radiative events such as bush fires and desert dust. Initial results from thirteen years of Bureau of Meteorology's (BOM) deseasonalised DNI and MODIS NASA-Terra aerosol optical depth (AOD) anomalies demonstrated strong negative correlations in north and southeast Australia along with strong variability in AOD (~0.03-0.05). Radiative transfer schemes, DNI and AOD anomaly correlations will be discussed for the population and transmission grid centric regions where current and planned CSP plants dispatch electricity to capture peak prices in the market. Aerosol and solar irradiance datasets include satellite and ground based assimilations from the national BOM, regional aerosol researchers and agencies. The presentation will provide an overview of this ASEFS project task on WRF and results to date. The overall goal of this ASEFS subtask is to develop a hybrid numerical weather prediction (NWP) and statistical/machine learning multi-model ensemble strategy that meets future operational requirements of CSP plant operators.

  10. Radiation dosimetry predicts IQ after conformal radiation therapy in pediatric patients with localized ependymoma

    International Nuclear Information System (INIS)

    Merchant, Thomas E.; Kiehna, Erin N.; Li Chenghong; Xiong Xiaoping; Mulhern, Raymond K.

    2005-01-01

    Purpose: To assess the effects of radiation dose-volume distribution on the trajectory of IQ development after conformal radiation therapy (CRT) in pediatric patients with ependymoma. Methods and Materials: The study included 88 patients (median age, 2.8 years ± 4.5 years) with localized ependymoma who received CRT (54-59.4 Gy) that used a 1-cm margin on the postoperative tumor bed. Patients were evaluated with tests that included IQ measures at baseline (before CRT) and at 6, 12, 24, 36, 48, and 60 months. Differential dose-volume histograms (DVH) were derived for total-brain, supratentorial-brain, and right and left temporal-lobe volumes. The data were partitioned into three dose intervals and integrated to create variables that represent the fractional volume that received dose over the specified intervals (e.g., V 0-20Gy , V 20-40Gy , V 40-65Gy ) and modeled with clinical variables to develop a regression equation to estimate IQ after CRT. Results: A total of 327 IQ tests were performed in 66 patients with infratentorial tumors and 20 with supratentorial tumors. The median follow-up was 29.4 months. For all patients, IQ was best estimated by age (years) at CRT; percent volume of the supratentorial brain that received doses between 0 and 20 Gy, 20 and 40 Gy, and 40 and 65 Gy; and time (months) after CRT. Age contributed significantly to the intercept (p > 0.0001), and the dose-volume coefficients were statistically significant (V 0-20Gy , p = 0.01; V 20-40Gy , p 40-65Gy , p = 0.04). A similar model was developed exclusively for patients with infratentorial tumors but not supratentorial tumors. Conclusion: Radiation dosimetry can be used to predict IQ after CRT in patients with localized ependymoma. The specificity of models may be enhanced by grouping according to tumor location

  11. Clinical impact of predictive assays for acute and late radiation morbidity

    International Nuclear Information System (INIS)

    Budach, W.; Classen, J.; Belka, C.; Bamberg, M.

    1998-01-01

    Background: Clinically reliable predictive assays for normal tissue radiation sensitivity would help to avoid severe radiation induced morbidity and result in individualized dose prescriptions. Profound differences of individual fibroblast and lymphocyte radiation sensitivity in vitro have been documented in patients with certain genetic syndromes but also in patients without known genetic disorders. The following review evaluates whether fibroblast or lymphocyte radiation sensitivity measured in vitro correlates with the degree of acute and late radiation induced morbidity. Results: Acute radiation side effects and lymphocyte sensitivity has been investigated in 2 studies. One of them reported an insecure correlation, the other no correlation at all. Fibroblast radiation sensitivity and the extent of acute radiation induced side effects on skin and mucosal sites has been compared in a total of 5 studies. None of these studies found a consistent significant correlation. Lymphocyte radiation sensitivity and late effects have been studied by 2 institutions. Late radiation induced skin and mucosal changes did not correlate with lymphocyte sensitivity in head and neck cancer patients, whereas in breast cancer patients a weak (R 2 =0.06) correlation between the degree of late skin reactions and lymphocyte sensitivity was observed. Late skin or mucosal radiation reactions and fibroblast sensitivity were examined by 5 research groups. Data analysis revealed significant correlations or at least a trend towards a significant correlation in all studies. The quality of the reported correlations expressed as R 2 ranged from 0.13 to 0.60, indicating a low predictive value. Conclusions: Lymphocyte radiation sensitivity as measured by currently available assays does not or only poorly correlate with acute and late effects of radiation in patients, precluding predictive tests based on lymphocyte sensitivity. Fibroblast radiation sensitivity does not correlate with acute but

  12. A radiation-hard dual-channel 12-bit 40 MS/s ADC prototype for the ATLAS liquid argon calorimeter readout electronics upgrade at the CERN LHC

    Energy Technology Data Exchange (ETDEWEB)

    Kuppambatti, J. [Columbia University, Dept. of Electrical Engineering, New York, NY (United States); Ban, J. [Columbia University, Nevis Laboratories, Irvington, NY (United States); Andeen, T., E-mail: tandeen@utexas.edu [Columbia University, Nevis Laboratories, Irvington, NY (United States); Brown, R.; Carbone, R. [Columbia University, Nevis Laboratories, Irvington, NY (United States); Kinget, P. [Columbia University, Dept. of Electrical Engineering, New York, NY (United States); Brooijmans, G.; Sippach, W. [Columbia University, Nevis Laboratories, Irvington, NY (United States)

    2017-05-21

    The readout electronics upgrade for the ATLAS Liquid Argon Calorimeters at the CERN Large Hadron Collider requires a radiation-hard ADC. The design of a radiation-hard dual-channel 12-bit 40 MS/s pipeline ADC for this use is presented. The design consists of two pipeline A/D channels each with four Multiplying Digital-to-Analog Converters followed by 8-bit Successive-Approximation-Register analog-to-digital converters. The custom design, fabricated in a commercial 130 nm CMOS process, shows a performance of 67.9 dB SNDR at 10 MHz for a single channel at 40 MS/s, with a latency of 87.5 ns (to first bit read out), while its total power consumption is 50 mW/channel. The chip uses two power supply voltages: 1.2 and 2.5 V. The sensitivity to single event effects during irradiation is measured and determined to meet the system requirements.

  13. Accompanying of parameters of color, brightness and hardness on polymeric films coated with pigmented inks cured by different radiation doses of ultraviolet light

    International Nuclear Information System (INIS)

    Bardi, M.A.G.; Machado, L.D.B.

    2011-01-01

    Complete text of publication follows. In the search for alternatives to traditional paint systems containing solvents, the curing process of polymer coatings by ultraviolet (UV) light has been widely studied and discussed, specially because of their high content of solids and null emission of VOCs. Radiation curing is defined as the conversion of a reactive liquid into a solid through polymerization and crosslinking reactions between the species, promoted by the interaction of the chemical system with the incident ionizing radiation. The appearance of the coated object (e.g., color, gloss) is a complex function of the light incident on the object, the optical scattering characteristic of the material, and human perception. Pigments are very fine powders being nearly insoluble in binders and solvents, but provide color and the ability to hide the underlying surface. In this context, this paper aims to investigate variations on color, brightness and hardness of UV-cured pigmented coatings by different doses. When it comes to irradiation exposition, the incorporation of pigments can preferentially cause its reflection or absorption of the incident radiation. Reflection usually occurs at the pigment surface within the resin so that the radiation has to pass through the top layers twice. Some degradation can, therefore, occur at the surface, and this is why materials frequently lose gloss on exposure.

  14. Prediction of monthly average global solar radiation based on statistical distribution of clearness index

    International Nuclear Information System (INIS)

    Ayodele, T.R.; Ogunjuyigbe, A.S.O.

    2015-01-01

    In this paper, probability distribution of clearness index is proposed for the prediction of global solar radiation. First, the clearness index is obtained from the past data of global solar radiation, then, the parameters of the appropriate distribution that best fit the clearness index are determined. The global solar radiation is thereafter predicted from the clearness index using inverse transformation of the cumulative distribution function. To validate the proposed method, eight years global solar radiation data (2000–2007) of Ibadan, Nigeria are used to determine the parameters of appropriate probability distribution for clearness index. The calculated parameters are then used to predict the future monthly average global solar radiation for the following year (2008). The predicted values are compared with the measured values using four statistical tests: the Root Mean Square Error (RMSE), MAE (Mean Absolute Error), MAPE (Mean Absolute Percentage Error) and the coefficient of determination (R"2). The proposed method is also compared to the existing regression models. The results show that logistic distribution provides the best fit for clearness index of Ibadan and the proposed method is effective in predicting the monthly average global solar radiation with overall RMSE of 0.383 MJ/m"2/day, MAE of 0.295 MJ/m"2/day, MAPE of 2% and R"2 of 0.967. - Highlights: • Distribution of clearnes index is proposed for prediction of global solar radiation. • The clearness index is obtained from the past data of global solar radiation. • The parameters of distribution that best fit the clearness index are determined. • Solar radiation is predicted from the clearness index using inverse transformation. • The method is effective in predicting the monthly average global solar radiation.

  15. Photon multiplicity in the hard radiation of 150 GeV electrons in an aligned germanium crystal

    International Nuclear Information System (INIS)

    Belkacem, A.; Chevallier, M.; Gaillard, M.J.; Genre, R.; Kirsch, R.; Poizat, J.C.; Remillieux, J.; Bologna, G.; Peigneux, J.P.; Sillou, D.; Spighel, M.; Cue, N.; Kimball, J.C.; Marsh, B.B.; Sun, C.R.

    1988-01-01

    Mean values m of photon multiplicity in the radiation of 150 GeV electrons directed at and near the axis of a 0.185 mm thick Ge crystal cooled to 100 K have been deduced from the measurements of pair conversion probabilities. Depending on the distribution of multiplicity assumed, values of m ranging from 3.8 to 4.3 are obtained for the previously reported anomalous radiation peak. (orig.)

  16. Predictive value of histologic tumor necrosis after radiation.

    Science.gov (United States)

    Chen, Y; Taghian, A G; Rosenberg, A E; O'Connell, J; Okunieff, P; Suit, H D

    2001-12-20

    Postsurgical evaluation of histologic changes of tumors after preoperative chemotherapy and/or radiotherapy has been a routine clinical practice of pathologists and oncologists. There appears to be secure evidence that the extent of tumor necrosis vs. viable tumor cells postchemotherapy is a clinically useful predictor of outcome. The significance of histologic tumor necrosis after radiotherapy, however, has not been clearly established and deserves further investigation. We investigated the correlation between histological extent of tumor necrosis, survival of tumor transplants, and radiation doses in an experimental model using three human tumor xenografts. Three human tumor cell lines were investigated: STS-26, SCC-21, and HGL-21. Tumors were grown subcutaneously in athymic nude mice and received external beam radiation of different doses. Tumors were excised 2 weeks postirradiation. One-half of the tumor was divided into 1-mm(3) fragments and transplanted to naive mice. The other half was examined for histologic tumor necrosis. Transplant survival was strongly correlated with radiation dose, TCD(p) (radiation dose that results in local tumor control in proportion, p, to irradiated tumors). In contrast, there was no clear association between transplant survival rate and the extent of tumor necrosis. The experimental model demonstrated a strong inverse correlation between radiation doses and tumor transplant survival. Histologic tumor necrosis did not correlate well with radiation doses or transplant survival rates. Despite common practices in histologic examination of tumors posttherapy, clinical interpretations and implications of histologic tumor necrosis after radiotherapy should be considered with caution. Copyright 2001 Wiley-Liss, Inc.

  17. Evaluation of mathematical methods for predicting optimum dose of gamma radiation in sugarcane (Saccharum sp.)

    International Nuclear Information System (INIS)

    Wu, K.K.; Siddiqui, S.H.; Heinz, D.J.; Ladd, S.L.

    1978-01-01

    Two mathematical methods - the reversed logarithmic method and the regression method - were used to compare the predicted and the observed optimum gamma radiation dose (OD 50 ) in vegetative propagules of sugarcane. The reversed logarithmic method, usually used in sexually propagated crops, showed the largest difference between the predicted and observed optimum dose. The regression method resulted in a better prediction of the observed values and is suggested as a better method for the prediction of optimum dose for vegetatively propagated crops. (author)

  18. Prediction of Ionizing Radiation Resistance in Bacteria Using a Multiple Instance Learning Model.

    Science.gov (United States)

    Aridhi, Sabeur; Sghaier, Haïtham; Zoghlami, Manel; Maddouri, Mondher; Nguifo, Engelbert Mephu

    2016-01-01

    Ionizing-radiation-resistant bacteria (IRRB) are important in biotechnology. In this context, in silico methods of phenotypic prediction and genotype-phenotype relationship discovery are limited. In this work, we analyzed basal DNA repair proteins of most known proteome sequences of IRRB and ionizing-radiation-sensitive bacteria (IRSB) in order to learn a classifier that correctly predicts this bacterial phenotype. We formulated the problem of predicting bacterial ionizing radiation resistance (IRR) as a multiple-instance learning (MIL) problem, and we proposed a novel approach for this purpose. We provide a MIL-based prediction system that classifies a bacterium to either IRRB or IRSB. The experimental results of the proposed system are satisfactory with 91.5% of successful predictions.

  19. Study of solar radiation prediction and modeling of relationships between solar radiation and meteorological variables

    International Nuclear Information System (INIS)

    Sun, Huaiwei; Zhao, Na; Zeng, Xiaofan; Yan, Dong

    2015-01-01

    Highlights: • We investigate relationships between solar radiation and meteorological variables. • A strong relationship exists between solar radiation and sunshine duration. • Daily global radiation can be estimated accurately with ARMAX–GARCH models. • MGARCH model was applied to investigate time-varying relationships. - Abstract: The traditional approaches that employ the correlations between solar radiation and other measured meteorological variables are commonly utilized in studies. It is important to investigate the time-varying relationships between meteorological variables and solar radiation to determine which variables have the strongest correlations with solar radiation. In this study, the nonlinear autoregressive moving average with exogenous variable–generalized autoregressive conditional heteroscedasticity (ARMAX–GARCH) and multivariate GARCH (MGARCH) time-series approaches were applied to investigate the associations between solar radiation and several meteorological variables. For these investigations, the long-term daily global solar radiation series measured at three stations from January 1, 2004 until December 31, 2007 were used in this study. Stronger relationships were observed to exist between global solar radiation and sunshine duration than between solar radiation and temperature difference. The results show that 82–88% of the temporal variations of the global solar radiation were captured by the sunshine-duration-based ARMAX–GARCH models and 55–68% of daily variations were captured by the temperature-difference-based ARMAX–GARCH models. The advantages of the ARMAX–GARCH models were also confirmed by comparison of Auto-Regressive and Moving Average (ARMA) and neutral network (ANN) models in the estimation of daily global solar radiation. The strong heteroscedastic persistency of the global solar radiation series was revealed by the AutoRegressive Conditional Heteroscedasticity (ARCH) and Generalized Auto

  20. Radiation hardness and timing studies of a monolithic TowerJazz pixel design for the new ATLAS Inner Tracker

    OpenAIRE

    Riegel, C; Backhaus, M; Hoorne, J W Van; Kugathasan, T; Musa, L; Pernegger, H; Riedler, P; Schaefer, D; Snoeys, W; Wagner, W

    2017-01-01

    A part of the upcoming HL-LHC upgrade of the ATLAS Detector is the construction of a new Inner Tracker. This upgrade opens new possibilities, but also presents challenges in terms of occupancy and radiation tolerance. For the pixel detector inside the inner tracker, hybrid modules containing passive silicon sensors and connected readout chips are presently used, but require expensive assembly techniques like fine-pitch bump bonding. Silicon devices fabricated in standard commercial CMOS techn...

  1. Vis-NIR hyperspectral imaging and multivariate analysis for prediction of the moisture content and hardness of Pistachio kernels roasted in different conditions

    Directory of Open Access Journals (Sweden)

    T Mohammadi Moghaddam

    2015-09-01

    of determination (R2, the root mean square error of prediction (RMSEP and the ratio of the standard deviation of the response variable to RMSEP (known as relative performance determinant (RPD were calculated. Results and discussion: Interpretation of hyperspectral data: The results showed that the spectra of the shell, the whole kernel and the internal part of the kernel have different patterns. The internal part of thekernel had 2 peaks at 630 nm and 690 nm, while the shell and the whole kernel had 1 peak at 670 nm and 720 nm, respectively and the peak of the whole kernel was sharper than that of the shell. The highest and lowest intensities were for the internal part of the kernel and the whole kernel, respectively. The spectral slope of the internal part is higher than that of the shell and the whole kernel at 500-700 nm. The effect of different pre-processing techniques and analysis on prediction of pistachio kernels properties: In the absence of pre-processing techniques, low correlation coefficients were observed for prediction of moisture content and hardness. However, with the use of pre-processing techniques, in some models, correlation coefficient and RPD increased and the RMSEP decreased. The results revealed that ANN models would predict moisture content and textural characteristics of roasted pistachio kernels better than PLSR models. Moisture content: ANN models can predict moisture content of roasted pistachio kernels better than PLSR models. In total, PLSR models showed low RPD and R2. For all samples, RPD was lower than 1.5, indicating that the developed models do not give an accurate prediction for moisture content. The best results with ANN method were achieved using a combination of SNV, wavelet and D1 for predicting moisture content with R2 =0.907 and RMSEP=0.179. Hardness: The results indicated that ANN models can predict the hardness better than PLSR models. The best results with PLSR models were achieved using a combination of SNV, wavelet and

  2. Gene expression signatures that predict radiation exposure in mice and humans.

    Directory of Open Access Journals (Sweden)

    Holly K Dressman

    2007-04-01

    Full Text Available The capacity to assess environmental inputs to biological phenotypes is limited by methods that can accurately and quantitatively measure these contributions. One such example can be seen in the context of exposure to ionizing radiation.We have made use of gene expression analysis of peripheral blood (PB mononuclear cells to develop expression profiles that accurately reflect prior radiation exposure. We demonstrate that expression profiles can be developed that not only predict radiation exposure in mice but also distinguish the level of radiation exposure, ranging from 50 cGy to 1,000 cGy. Likewise, a molecular signature of radiation response developed solely from irradiated human patient samples can predict and distinguish irradiated human PB samples from nonirradiated samples with an accuracy of 90%, sensitivity of 85%, and specificity of 94%. We further demonstrate that a radiation profile developed in the mouse can correctly distinguish PB samples from irradiated and nonirradiated human patients with an accuracy of 77%, sensitivity of 82%, and specificity of 75%. Taken together, these data demonstrate that molecular profiles can be generated that are highly predictive of different levels of radiation exposure in mice and humans.We suggest that this approach, with additional refinement, could provide a method to assess the effects of various environmental inputs into biological phenotypes as well as providing a more practical application of a rapid molecular screening test for the diagnosis of radiation exposure.

  3. Predicting diffuse radiation where only data on sunshine duration is available

    International Nuclear Information System (INIS)

    Massaquoi, J.G.M.

    1985-12-01

    In most locations there are no data on either global or diffuse radiation. Yet most of the existing correlations for predicting the latter require measured data on the former. This is because these correlations express the diffuse radiation as a function of the clearness index. To overcome this, one approach has been to develop correlations of diffuse radiation as a function of sunshine hours. This paper considers another approach: that of using predicted values of global radiation when measured values are not available. With this approach one could then use correlations of diffuse radiation as a function of clearness index. In this paper we have carried out a comparative assessment of the two approaches and reached the conclusion that the latter is more accurate. (author)

  4. Improving radiation hardness in space-based Charge-Coupled Devices through the narrowing of the charge transfer channel

    Science.gov (United States)

    Hall, D. J.; Skottfelt, J.; Soman, M. R.; Bush, N.; Holland, A.

    2017-12-01

    Charge-Coupled Devices (CCDs) have been the detector of choice for imaging and spectroscopy in space missions for several decades, such as those being used for the Euclid VIS instrument and baselined for the SMILE SXI. Despite the many positive properties of CCDs, such as the high quantum efficiency and low noise, when used in a space environment the detectors suffer damage from the often-harsh radiation environment. High energy particles can create defects in the silicon lattice which act to trap the signal electrons being transferred through the device, reducing the signal measured and effectively increasing the noise. We can reduce the impact of radiation on the devices through four key methods: increased radiation shielding, device design considerations, optimisation of operating conditions, and image correction. Here, we concentrate on device design operations, investigating the impact of narrowing the charge-transfer channel in the device with the aim of minimising the impact of traps during readout. Previous studies for the Euclid VIS instrument considered two devices, the e2v CCD204 and CCD273, the serial register of the former having a 50 μm channel and the latter having a 20 μm channel. The reduction in channel width was previously modelled to give an approximate 1.6× reduction in charge storage volume, verified experimentally to have a reduction in charge transfer inefficiency of 1.7×. The methods used to simulate the reduction approximated the charge cloud to a sharp-edged volume within which the probability of capture by traps was 100%. For high signals and slow readout speeds, this is a reasonable approximation. However, for low signals and higher readout speeds, the approximation falls short. Here we discuss a new method of simulating and calculating charge storage variations with device design changes, considering the absolute probability of capture across the pixel, bringing validity to all signal sizes and readout speeds. Using this method, we

  5. Thermal Radiometer Signal Processing Using Radiation Hard CMOS Application Specific Integrated Circuits for Use in Harsh Planetary Environments

    Science.gov (United States)

    Quilligan, G.; DuMonthier, J.; Aslam, S.; Lakew, B.; Kleyner, I.; Katz, R.

    2015-01-01

    Thermal radiometers such as proposed for the Europa Clipper flyby mission require low noise signal processing for thermal imaging with immunity to Total Ionizing Dose (TID) and Single Event Latchup (SEL). Described is a second generation Multi- Channel Digitizer (MCD2G) Application Specific Integrated Circuit (ASIC) that accurately digitizes up to 40 thermopile pixels with greater than 50 Mrad (Si) immunity TID and 174 MeV-sq cm/mg SEL. The MCD2G ASIC uses Radiation Hardened By Design (RHBD) techniques with a 180 nm CMOS process node.

  6. On the role of radiation and dimensionality in predicting flow opposed flame spread over thin fuels

    Science.gov (United States)

    Kumar, Chenthil; Kumar, Amit

    2012-06-01

    In this work a flame-spread model is formulated in three dimensions to simulate opposed flow flame spread over thin solid fuels. The flame-spread model is coupled to a three-dimensional gas radiation model. The experiments [1] on downward spread and zero gravity quiescent spread over finite width thin fuel are simulated by flame-spread models in both two and three dimensions to assess the role of radiation and effect of dimensionality on the prediction of the flame-spread phenomena. It is observed that while radiation plays only a minor role in normal gravity downward spread, in zero gravity quiescent spread surface radiation loss holds the key to correct prediction of low oxygen flame spread rate and quenching limit. The present three-dimensional simulations show that even in zero gravity gas radiation affects flame spread rate only moderately (as much as 20% at 100% oxygen) as the heat feedback effect exceeds the radiation loss effect only moderately. However, the two-dimensional model with the gas radiation model badly over-predicts the zero gravity flame spread rate due to under estimation of gas radiation loss to the ambient surrounding. The two-dimensional model was also found to be inadequate for predicting the zero gravity flame attributes, like the flame length and the flame width, correctly. The need for a three-dimensional model was found to be indispensable for consistently describing the zero gravity flame-spread experiments [1] (including flame spread rate and flame size) especially at high oxygen levels (>30%). On the other hand it was observed that for the normal gravity downward flame spread for oxygen levels up to 60%, the two-dimensional model was sufficient to predict flame spread rate and flame size reasonably well. Gas radiation is seen to increase the three-dimensional effect especially at elevated oxygen levels (>30% for zero gravity and >60% for normal gravity flames).

  7. Predictive assays and their role in selection of radiation as the therapeutic modality

    International Nuclear Information System (INIS)

    2002-07-01

    Radiation therapy is a modality to treat cancer patients using ionising radiation. Ionising radiation kills cancer (or malignant tumour) cells and hopefully cures the patient. If some cancer cells survive the treatment, those cells would ultimately multiply again and eventually kill the patient. Although radiation is intended to focus on the cancer, irradiation of the normal tissues is unavoidable. The higher the radiation dose given to the cancer, the greater the chance of eradicating it. On the other hand, the greater the radiation dose, the greater the probability of severe morbidity or side effects. Thus, optimising the dose for the patients is crucial. Human cancers have variable radiation sensitivities. Many factors influence the sensitivity. These factors include simple parameters such as tumour size, cellular sensitivity, such as repair capacity, and tumour environment, such as oxygen content. If we can predict the radiation sensitivity of the individual tumours prior to radiation therapy, or even during the radiation therapy, it would give us valuable information with regard to determining the optimal dose. Such an approach has led to the search for predictive assays. Recent advances in molecular technology and equipment have facilitated progress in this field. Some of the studies relied on tumour tissues taken by biopsy, while others focused on cell cycle parameters, which could suggest optimal fractionation schedules. The IAEA's sub-programme on Applied Radiation Biology and Radiotherapy aims to assist Member States in establishing or upgrading radiotherapy facilities to contribute effectively to cancer treatment for palliative or curative purposes and to provide assistance towards the enhancement of radiation-induced therapeutic gain. The Co-ordinated Research Project (CRP) on Radiation Responsiveness Criteria for Human Tumours as Determinant for Therapeutic Modality Planning was initiated in 1992 to address this problem. This publication was assembled

  8. Bread-Board Testing of the Radiation Hard Electron Monitor (RADEM) being developed for the ESA JUICE Mission

    Science.gov (United States)

    Mrigakshi, Alankrita; Hajdas, Wojtek; Marcinkowski, Radoslaw; Xiao, Hualin; Goncalves, Patricia; Pinto, Marco; Pinto, Costa; Marques, Arlindo; Meier, Dirk

    2016-04-01

    The RADEM instrument will serve as the radiation monitor for the JUICE spacecraft. It will characterize the highly dynamic radiation environment of the Jovian system by measuring the energy spectra of energetic electrons and protons up to 40 MeV and 250 MeV, respectively. It will also determine the directionality of 0.3-10 MeV electrons. Further goals include the detection of heavy ions, and the determination of the corresponding LET spectra and dose rates. Here, the tests of the Electron and Proton Telescopes, and the Directionality Detector of the RADEM Bread-Board model are described. The objective of these tests is to validate RADEM design and physical concept applied therein. The tests were performed at various irradiation facilities at the Paul Scherrer Institute (PSI) where energy ranges relevant for space applications can be covered (electrons: ≤100 MeV and protons: ≤230 MeV). The measured values are also compared with GEANT4 Monte-Carlo Simulation results.

  9. A novel epitaxially grown LSO-based thin-film scintillator for micro-imaging using hard synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Douissard, P.A.; Martin, T.; Chevalier, V.; Rack, A. [European Synchrotron Radiat Facil, F-38043 Grenoble, (France); Cecilia, A.; Baumbach, T.; Rack, A. [Karlsruhe Inst Technol ANKA, D-76021 Karlsruhe, (Germany); Couchaud, M. [CEA LETI, F-38054 Grenoble, (France); Dupre, K. [FEE GmbH, D-55743 Idar Oberstein, (Germany); Kuhbacher, M. [Helmholtz Zentrum Berlin Mat and Energie, D-14109 Berlin, (Germany)

    2010-07-01

    The efficiency of high-resolution pixel detectors for hard X-rays is nowadays one of the major criteria which drives the feasibility of imaging experiments and in general the performance of an experimental station for synchrotron-based microtomography and radiography. Here the luminescent screen used for the indirect detection is focused on in order to increase the detective quantum efficiency a novel scintillator based on doped Lu{sub 2}SiO{sub 5} (LSO), epitaxially grown as thin film via the liquid phase epitaxy technique. It is shown that, by using adapted growth and doping parameters as well as a dedicated substrate, the scintillation behaviour of a LSO-based thin crystal together with the high stopping power of the material allows for high-performance indirect X-ray detection. In detail, the conversion efficiency, the radioluminescence spectra, the optical absorption spectra under UV/visible-light and the afterglow are investigated. A set-up to study the effect of the thin-film scintillator's temperature on its conversion efficiency is described as well it delivers knowledge which is important when working with higher photon flux densities and the corresponding high heat load on the material. Additionally, X-ray imaging systems based on different diffraction-limited visible-light optics and CCD cameras using among others LSO-based thin film are compared. Finally, the performance of the LSO thin film is illustrated by imaging a honey bee leg, demonstrating the value of efficient high-resolution computed tomography for life sciences. (authors)

  10. Total ionizing dose radiation hardness of the ATLAS MDT-ASD and the HP-Agilent 0.5 um CMOS process

    CERN Document Server

    Posch, C

    2002-01-01

    A total ionizing dose (TID) test of the MDT-ASD, the ATLAS MDT front-end chip has been performed at the Harvard Cyclotron Lab. The MDT-ASD is an 8-channel drift tube read-out ASIC fabricated in a commercial 0.5 um CMOS process (AMOS14TB). The accumulated TID at the end of the test was 300 krad, delivered by 160 MeV protons at a rate of approximately 70 rad/sec. All 10 irradiated chips retained their full functionality and performance and showed only irrelevantly small changes in device parameters. As the total accumulated dose is substantially higher than the relevant ATLAS Radiation Tolerance Criteria (RTCtid), the results of this test indicate that MDT-ASD meets the ATLAS TID radiation hardness requirements. In addition, the results of this test correspond well with results of a 30 keV gamma TID irradiation test performed by us on an earlier prototype at the CERN x-ray facility as well as with results of other irradiation test on this process found in literature.

  11. Optical properties, luminescence quenching mechanism and radiation hardness of Eu-doped GaN red powder phosphor

    International Nuclear Information System (INIS)

    Jadwisienczak, W.; Wisniewski, K.; Spencer, M.; Thomas, T.; Ingram, D.

    2010-01-01

    We report on the luminescence quenching mechanism of Eu-doped GaN powder phosphor produced with a low-cost, high yield rapid-ammonothermal method. We have studied as-synthesized and acid rinsed Eu-doped GaN powders with the Eu concentration of ∼0.5 at.%. The Eu-doped GaN photoluminescence (PL) was investigated with 325 nm excitation wavelength at hydrostatic pressures up to 7.7 GPa in temperature range between 12 K and 300 K. The room temperature integrated Eu 3+ ion PL intensity from acid rinsed material is a few times stronger than from the as-synthesized material. The temperature dependent PL studies revealed that the thermal quenching of the dominant Eu 3+ ion transition ( 5 D 0 → 7 F 2 ) at 622 nm is stronger in the chemically modified phosphor indicating more efficient coupling between the Eu 3+ ion and passivated GaN powder grains. Furthermore, it was found that thermal quenching of Eu 3+ ion emission intensity can be completely suppressed in studied materials by applied pressure. This is due to stronger localization of bound exciton on Eu 3+ ion trap induced by hydrostatic pressure. Furthermore, the effect of 2 MeV oxygen irradiation on the PL properties has been investigated for highly efficient Eu-doped GaN phosphor embedded in KBr-GaN:Eu 3+ composite. Fairly good radiation damage resistance was obtained for 1.7 x 10 12 to 5 x 10 13 cm -2 oxygen fluence. Preliminary data indicate that Eu-doped GaN powder phosphor can be considered for devices in a radiation environment.

  12. Development of beam halo monitors for the European XFEL using radiation hard sensors and demonstration of the technology at FLASH

    International Nuclear Information System (INIS)

    Ignatenko, Alexandr

    2015-05-01

    The European X-Ray Free-Electron Laser (E-XFEL), currently under construction in Hamburg, Germany, is intended to be an international linear accelerator (linac) based user facility. Its electron beam can carry maximal average power of 600 kW. A beam with such a high power needs to be carefully transmitted through the machine and safely dumped after utilization. This is supported by various diagnostics tools. A Beam Halo Monitor (BHM) based on synthetic diamond and sapphire sensors has been designed. Diamond sensors are developed by the company element6 for the detection of ionizing radiation and used previously elsewhere. Sapphire sensors are in this thesis applied for the first time. The BHM concept has been applied already at the Free-electron Laser in Hamburg (FLASH). A module with four diamond and four sapphire sensors was designed, installed inside the beam pipe, commissioned, calibrated and has been successfully operated for 4 years. The system contributed significantly to safe and efficient operation of FLASH. Both types of the sensors for the BHM were characterized. Measurements of radiation tolerance are done in a 10 MeV electron beam for polycrystalline CVD (pCVD) diamond sensors for the first time up to a dose of 10 MGy and for sapphire sensors up to 5 MGy. The charge collection efficiency (CCE) drops as a function of the absorbed dose, is however still sufficient for application as a BHM. To improve a main sensor characteristic, the charge collection efficiency, for sapphire sensors the impurity concentration was reduced and different growth techniques were compared. Finally, charge collection efficiency of about 5 % for a bias voltage of 500 V was reached. The BHM concept for the XFEL is designed and in the construction phase.

  13. Prediction of Large Vessel Occlusions in Acute Stroke: National Institute of Health Stroke Scale Is Hard to Beat.

    Science.gov (United States)

    Vanacker, Peter; Heldner, Mirjam R; Amiguet, Michael; Faouzi, Mohamed; Cras, Patrick; Ntaios, George; Arnold, Marcel; Mattle, Heinrich P; Gralla, Jan; Fischer, Urs; Michel, Patrik

    2016-06-01

    Endovascular treatment for acute ischemic stroke with a large vessel occlusion was recently shown to be effective. We aimed to develop a score capable of predicting large vessel occlusion eligible for endovascular treatment in the early hospital management. Retrospective, cohort study. Two tertiary, Swiss stroke centers. Consecutive acute ischemic stroke patients (1,645 patients; Acute STroke Registry and Analysis of Lausanne registry), who had CT angiography within 6 and 12 hours of symptom onset, were categorized according to the occlusion site. Demographic and clinical information was used in logistic regression analysis to derive predictors of large vessel occlusion (defined as intracranial carotid, basilar, and M1 segment of middle cerebral artery occlusions). Based on logistic regression coefficients, an integer score was created and validated internally and externally (848 patients; Bernese Stroke Registry). None. Large vessel occlusions were present in 316 patients (21%) in the derivation and 566 (28%) in the external validation cohort. Five predictors added significantly to the score: National Institute of Health Stroke Scale at admission, hemineglect, female sex, atrial fibrillation, and no history of stroke and prestroke handicap (modified Rankin Scale score, < 2). Diagnostic accuracy in internal and external validation cohorts was excellent (area under the receiver operating characteristic curve, 0.84 both). The score performed slightly better than National Institute of Health Stroke Scale alone regarding prediction error (Wilcoxon signed rank test, p < 0.001) and regarding discriminatory power in derivation and pooled cohorts (area under the receiver operating characteristic curve, 0.81 vs 0.80; DeLong test, p = 0.02). Our score accurately predicts the presence of emergent large vessel occlusions, which are eligible for endovascular treatment. However, incorporation of additional demographic and historical information available on hospital arrival

  14. Response-driven imaging biomarkers for predicting radiation necrosis of the brain

    International Nuclear Information System (INIS)

    Nazem-Zadeh, Mohammad-Reza; Chapman, Christopher H; Lawrence, Theodore S; Ten Haken, Randall K; Tsien, Christina I; Cao, Yue; Chenevert, Thomas

    2014-01-01

    Radiation necrosis is an uncommon but severe adverse effect of brain radiation therapy (RT). Current predictive models based on radiation dose have limited accuracy. We aimed to identify early individual response biomarkers based upon diffusion tensor (DT) imaging and incorporated them into a response model for prediction of radiation necrosis. Twenty-nine patients with glioblastoma received six weeks of intensity modulated RT and concurrent temozolomide. Patients underwent DT-MRI scans before treatment, at three weeks during RT, and one, three, and six months after RT. Cases with radiation necrosis were classified based on generalized equivalent uniform dose (gEUD) of whole brain and DT index early changes in the corpus callosum and its substructures. Significant covariates were used to develop normal tissue complication probability models using binary logistic regression. Seven patients developed radiation necrosis. Percentage changes of radial diffusivity (RD) in the splenium at three weeks during RT and at six months after RT differed significantly between the patients with and without necrosis (p = 0.05 and p = 0.01). Percentage change of RD at three weeks during RT in the 30 Gy dose–volume of the splenium and brain gEUD combined yielded the best-fit logistic regression model. Our findings indicate that early individual response during the course of RT, assessed by radial diffusivity, has the potential to aid the prediction of delayed radiation necrosis, which could provide guidance in dose-escalation trials. (paper)

  15. Predicting Behavioral Problems in Craniopharyngioma Survivors after Conformal Radiation Therapy

    Science.gov (United States)

    Dolson, Eugenia P.; Conklin, Heather M.; Li, Chenghong; Xiong, Xiaoping; Merchant, Thomas E.

    2009-01-01

    Background Although radiation therapy is a primary treatment for craniopharyngioma, it can exacerbate existing problems related to the tumor and pre-irradiation management. Survival is often marked by neurologic deficits, panhypopituitarism, diabetes insipidus, cognitive deficiencies and behavioral and social problems. Procedure The Achenbach Child Behavior Checklist (CBCL) was used to evaluate behavioral and social problems during the first five years of follow-up in 27 patients with craniopharyngioma treated with conformal radiation therapy. Results All group averages for the CBCL scales were within the age-typical range at pre-irradiation baseline. Extent of surgical resection was implicated in baseline differences for the Internalizing, Externalizing, Behavior Problem and Social scores. Significant longitudinal changes were found in Internalizing, Externalizing, Behavior Problem and School scores that correlated with tumor and treatment related factors. Conclusions The most common variables implicated in post-irradiation behavioral and social problems were CSF shunting, presence of an Ommaya reservoir, diabetes insipidus, and low pre-irradiation growth hormone levels. PMID:19191345

  16. Radiation hardness test of un-doped CsI crystals and Silicon Photomultipliers for the Mu2e calorimeter

    Science.gov (United States)

    Baccaro, S.; Cemmi, A.; Cordelli, M.; Diociaiuti, E.; Donghia, R.; Giovannella, S.; Loreti, S.; Miscetti, S.; Pillon, M.; Sarra, I.

    2017-11-01

    The Mu2e calorimeter is composed by 1400 un-doped CsI crystals coupled to large area UV extended Silicon Photomultipliers arranged in two annular disks. This calorimeter has to provide precise information on energy, timing and position. It should also be fast enough to handle the high rate background and it must operate and survive in a high radiation environment. Simulation studies estimated that, in the hottest regions, each crystal will absorb a dose of 300 Gy and will be exposed to a neutron fluency of 6 × 1011 n/cm2 in 3 years of running. Test of un-doped CsI crystals irradiated up to 900 Gy and to a neutron fluency up to 9 × 1011 n/cm2 have been performed at CALLIOPE and FNG ENEA facilities in Italy. We present our study on the variation of light yield (LY) and longitudinal response uniformity (LRU) of these crystals after irradiation. The ionization dose does not modify LRU while a 20% reduction in LY is observed at 900 Gy. Similarly, the neutron flux causes an acceptable LY deterioration (≤ 15%). A neutron irradiation test on different types of SIPMs (two different array models from Hamamatsu and one from FBK) have also been carried out by measuring the variation of the leakage current and the charge response to an ultraviolet led. We concluded that, in the experiment, we will need to cool down the SIPMs to 0 °C reduce the leakage current to an acceptable level.

  17. Prediction of the strength of concrete radiation shielding based on LS-SVM

    International Nuclear Information System (INIS)

    Juncai, Xu; Qingwen, Ren; Zhenzhong, Shen

    2015-01-01

    Highlights: • LS-SVM was introduced for prediction of the strength of RSC. • A model for prediction of the strength of RSC was implemented. • The grid search algorithm was used to optimize the parameters of the LS-SVM. • The performance of LS-SVM in predicting the strength of RSC was evaluated. - Abstract: Radiation-shielding concrete (RSC) and conventional concrete differ in strength because of their distinct constituents. Predicting the strength of RSC with different constituents plays a vital role in radiation shielding (RS) engineering design. In this study, a model to predict the strength of RSC is established using a least squares-support vector machine (LS-SVM) through grid search algorithm. The algorithm is used to optimize the parameters of the LS-SVM on the basis of traditional prediction methods for conventional concrete. The predicted results of the LS-SVM model are compared with the experimental data. The results of the prediction are stable and consistent with the experimental results. In addition, the studied parameters exhibit significant effects on the simulation results. Therefore, the proposed method can be applied in predicting the strength of RSC, and the predicted results can be adopted as an important reference for RS engineering design

  18. External radiation survey and dose predictions for Rongelap, Utirik, Rongerik, Ailuk, and Wotje Atolls

    International Nuclear Information System (INIS)

    Greenhouse, N.A.; Miltenberger, R.P.

    1977-01-01

    External radiation measurements were made at several atolls in the northern Marshall Islands, which are known or suspected to have been the recipients of tropospheric fallout during the Pacific Testing Programs. Sufficient data were available to ascertain realistic dose predictions for the inhabitants of Rongelap and Utirik Atolls where the 30 year integral doses from external sources exclusive of background radiation were 0.65 and 0.06 rem respectively. These estimates are based on realistic life-style models based on observations of each atoll community. Ailuk and Wotje Atolls were found to be represenatives of regional background radiation levels

  19. Prediction of the thickness of the compensator filter in radiation therapy using computational intelligence

    International Nuclear Information System (INIS)

    Dehlaghi, Vahab; Taghipour, Mostafa; Haghparast, Abbas; Roshani, Gholam Hossein; Rezaei, Abbas; Shayesteh, Sajjad Pashootan; Adineh-Vand, Ayoub; Karimi, Gholam Reza

    2015-01-01

    In this study, artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS) are investigated to predict the thickness of the compensator filter in radiation therapy. In the proposed models, the input parameters are field size (S), off-axis distance, and relative dose (D/D 0 ), and the output is the thickness of the compensator. The obtained results show that the proposed ANN and ANFIS models are useful, reliable, and cheap tools to predict the thickness of the compensator filter in intensity-modulated radiation therapy

  20. Prediction of the thickness of the compensator filter in radiation therapy using computational intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Dehlaghi, Vahab; Taghipour, Mostafa; Haghparast, Abbas [Department of Biomedical Engineering, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Roshani, Gholam Hossein [School of Energy, Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of); Rezaei, Abbas [Department of Electrical Engineering, Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of); Shayesteh, Sajjad Pashootan [Department of Biomedical Engineering, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Adineh-Vand, Ayoub [Department of Computer Engineering, Islamic Azad University, Kermanshah (Iran, Islamic Republic of); Department of Electrical Engineering, Razi University, Kermanshah (Iran, Islamic Republic of); Karimi, Gholam Reza, E-mail: ghkarimi@razi.ac.ir [Department of Electrical Engineering, Razi University, Kermanshah (Iran, Islamic Republic of)

    2015-04-01

    In this study, artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS) are investigated to predict the thickness of the compensator filter in radiation therapy. In the proposed models, the input parameters are field size (S), off-axis distance, and relative dose (D/D{sub 0}), and the output is the thickness of the compensator. The obtained results show that the proposed ANN and ANFIS models are useful, reliable, and cheap tools to predict the thickness of the compensator filter in intensity-modulated radiation therapy.

  1. Hardness variability in commercial technologies

    International Nuclear Information System (INIS)

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-01-01

    The radiation hardness of commercial Floating Gate 256K E 2 PROMs from a single diffusion lot was observed to vary between 5 to 25 krad(Si) when irradiated at a low dose rate of 64 mrad(Si)/s. Additional variations in E 2 PROM hardness were found to depend on bias condition and failure mode (i.e., inability to read or write the memory), as well as the foundry at which the part was manufactured. This variability is related to system requirements, and it is shown that hardness level and variability affect the allowable mode of operation for E 2 PROMs in space applications. The radiation hardness of commercial 1-Mbit CMOS SRAMs from Micron, Hitachi, and Sony irradiated at 147 rad(Si)/s was approximately 12, 13, and 19 krad(Si), respectively. These failure levels appear to be related to increases in leakage current during irradiation. Hardness of SRAMs from each manufacturer varied by less than 20%, but differences between manufacturers are significant. The Qualified Manufacturer's List approach to radiation hardness assurance is suggested as a way to reduce variability and to improve the hardness level of commercial technologies

  2. CdTe Timepix detectors for single-photon spectroscopy and linear polarimetry of high-flux hard x-ray radiation.

    Science.gov (United States)

    Hahn, C; Weber, G; Märtin, R; Höfer, S; Kämpfer, T; Stöhlker, Th

    2016-04-01

    Single-photon spectroscopy of pulsed, high-intensity sources of hard X-rays - such as laser-generated plasmas - is often hampered by the pileup of several photons absorbed by the unsegmented, large-volume sensors routinely used for the detection of high-energy radiation. Detectors based on the Timepix chip, with a segmentation pitch of 55 μm and the possibility to be equipped with high-Z sensor chips, constitute an attractive alternative to commonly used passive solutions such as image plates. In this report, we present energy calibration and characterization measurements of such devices. The achievable energy resolution is comparable to that of scintillators for γ spectroscopy. Moreover, we also introduce a simple two-detector Compton polarimeter setup with a polarimeter quality of (98 ± 1)%. Finally, a proof-of-principle polarimetry experiment is discussed, where we studied the linear polarization of bremsstrahlung emitted by a laser-driven plasma and found an indication of the X-ray polarization direction depending on the polarization state of the incident laser pulse.

  3. Factors predicting radiation pneumonitis in locally advanced non-small cell lung cancer

    International Nuclear Information System (INIS)

    Kim, Myung Soo; Lee, Ji Hae; Ha, Bo Ram; Lee, Re Na

    2011-01-01

    Thoracic radiotherapy is a major treatment modality of stage III non-small cell lung cancer. The normal lung tissue is sensitive to radiation and radiation pneumonitis is the most important dose-limiting complication of thoracic radiation therapy. This study was performed to identify the clinical and dosimetric parameters related to the risk of radiation pneumonitis after definitive radiotherapy in stage III non-small cell cancer patients. The medical records were reviewed for 49 patients who completed definitive radiation therapy for locally advanced non-small cell lung cancer from August 2000 to February 2010. Radiation therapy was delivered with the daily dose of 1.8 Gy to 2.0 Gy and the total radiation dose ranged from 50.0 Gy to 70.2 Gy (median, 61.2 Gy). Elective nodal irradiation was delivered at a dose of 45.0 Gy to 50.0 Gy. Seven patients (14.3%) were treated with radiation therapy alone and forty two patients (85.7%) were treated with chemotherapy either sequentially or concurrently. Twenty-five cases (51.0%) out of 49 cases experienced radiation pneumonitis. According to the radiation pneumonitis grade, 10 (20.4%) were grade 1, 9 (18.4%) were grade 2, 4 (8.2%) were grade 3, and 2 (4.1%) were grade 4. In the univariate analyses, no clinical factors including age, sex, performance status, smoking history, underlying lung disease, tumor location, total radiation dose and chemotherapy were associated with grade ≥2 radiation pneumonitis. In the subgroup analysis of the chemotherapy group, concurrent rather than sequential chemotherapy was significantly related to grade ≥2 radiation pneumonitis comparing sequential chemotherapy. In the univariate analysis with dosimetric factors, mean lung dose (MLD), V20, V30, V40, MLDipsi, V20ipsi, V30ipsi, and V40ipsi were associated with grade ≥2 radiation pneumonitis. In addition, multivariate analysis showed that MLD and V30 were independent predicting factors for grade ≥2 radiation pneumonitis. Concurrent

  4. Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

  5. Hard coatings

    International Nuclear Information System (INIS)

    Dan, J.P.; Boving, H.J.; Hintermann, H.E.

    1993-01-01

    Hard, wear resistant and low friction coatings are presently produced on a world-wide basis, by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, CVD and PVD. Some of the most advanced processes, especially those dedicated to thin film depositions, basically belong to CVD or PVD technologies, and will be looked at in more detail. The hard coatings mainly consist of oxides, nitrides, carbides, borides or carbon. Over the years, many processes have been developed which are variations and/or combinations of the basic CVD and PVD methods. The main difference between these two families of deposition techniques is that the CVD is an elevated temperature process (≥ 700 C), while the PVD on the contrary, is rather a low temperature process (≤ 500 C); this of course influences the choice of substrates and properties of the coating/substrate systems. Fundamental aspects of the vapor phase deposition techniques and some of their influences on coating properties will be discussed, as well as the very important interactions between deposit and substrate: diffusions, internal stress, etc. Advantages and limitations of CVD and PVD respectively will briefly be reviewed and examples of applications of the layers will be given. Parallel to the development and permanent updating of surface modification technologies, an effort was made to create novel characterisation methods. A close look will be given to the coating adherence control by means of the scratch test, at the coating hardness measurement by means of nanoindentation, at the coating wear resistance by means of a pin-on-disc tribometer, and at the surface quality evaluation by Atomic Force Microscopy (AFM). Finally, main important trends will be highlighted. (orig.)

  6. Prediction of a photovoltaic system performance using cumulative frequency curves of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lasnier, F; Sivoththaman, S [Asian Inst. of Technology, Bangkok (TH). Div. of Energy Technology

    1990-01-01

    The system performance of stand-alone photovoltaic systems is analysed. From the hourly radiation data for Bangkok (from 1984 to 1987) the cumulative frequency curves of radiation are generated and a typical meteorological day (TMD) is created each year. The system performance is determined using both the TMD radiation and the actual radiation values. The comparison results show that the TMD method can be applied for the sizing of stand-alone photovoltaic systems. The storage batteries of realistic sizes usually exhibit a daily cyclic variation in state-of-charge, with constant load consumption. Only very large and unrealistic sizes of batteries show a seasonal variation in state-of-charge. This is the fact that prompted the attempt to predict the system performance for a season by using a single representative day (TMD) of that season. Apart from giving reliable results, the TMD method significantly reduces the computation time and simplifies the process. (author).

  7. Uncertainty and Sensitivity Analysis of Afterbody Radiative Heating Predictions for Earth Entry

    Science.gov (United States)

    West, Thomas K., IV; Johnston, Christopher O.; Hosder, Serhat

    2016-01-01

    The objective of this work was to perform sensitivity analysis and uncertainty quantification for afterbody radiative heating predictions of Stardust capsule during Earth entry at peak afterbody radiation conditions. The radiation environment in the afterbody region poses significant challenges for accurate uncertainty quantification and sensitivity analysis due to the complexity of the flow physics, computational cost, and large number of un-certain variables. In this study, first a sparse collocation non-intrusive polynomial chaos approach along with global non-linear sensitivity analysis was used to identify the most significant uncertain variables and reduce the dimensions of the stochastic problem. Then, a total order stochastic expansion was constructed over only the important parameters for an efficient and accurate estimate of the uncertainty in radiation. Based on previous work, 388 uncertain parameters were considered in the radiation model, which came from the thermodynamics, flow field chemistry, and radiation modeling. The sensitivity analysis showed that only four of these variables contributed significantly to afterbody radiation uncertainty, accounting for almost 95% of the uncertainty. These included the electronic- impact excitation rate for N between level 2 and level 5 and rates of three chemical reactions in uencing N, N(+), O, and O(+) number densities in the flow field.

  8. A biological approach to the interspecies prediction of radiation-induced mortality risk

    International Nuclear Information System (INIS)

    Carnes, B.A.; Grahn, D.; Olshansky, S.J.

    1997-01-01

    Evolutionary explanations for why sexually reproducing organisms grow old suggest that the forces of natural selection affect the ages when diseases occur that are subject to a genetic influence (referred to here as intrinsic diseases). When extended to the population level for a species, this logic leads to the general prediction that age-specific death rates from intrinsic causes should begin to rise as the force of selection wanes once the characteristic age of sexual maturity is attained. Results consistent with these predictions have been found for laboratory mice, beagles, and humans where, after adjusting for differences in life span, it was demonstrated that these species share a common age pattern of mortality for intrinsic causes of death. In quantitative models used to predict radiation-induced mortality, risks are often expressed as multiples of those observed in a control population. A control population, however, is an aging population. As such, mortality risks related to exposure must be interpreted relative to the age-specific risk of death associated with aging. Given the previous success in making interspecies predictions of age-related mortality, the purpose of this study was to determine whether radiation-induced mortality observed in one species could also be predicted quantitatively from a model used to describe the mortality consequences of exposure to radiation in a different species. Mortality data for B6CF 1 mice and beagles exposed to 60 Co γ-rays for the duration of life were used for analysis

  9. A prediction model for the radiation safety management behavior of medical cyclotrons

    International Nuclear Information System (INIS)

    Jung, Ji Hye; Han, Eun Ok; Kim, Ssang Tae

    2008-01-01

    This study attempted to provide reference materials for improving the behavior level in radiation safety managements by drawing a prediction model that affects the radiation safety management behavior because the radiation safety management of medical Cyclotrons, which can be used to produce radioisotopes, is an important factor that protects radiation caused diseases not only for radiological operators but average users. In addition, this study obtained follows results through the investigation applied from January 2 to January 30, 2008 for the radiation safety managers employed in 24 authorized organizations, which have already installed Cyclotrons, through applying a specific form of questionnaire in which the validity was guaranteed by reference study, site investigation, and focus discussion by related experts. The radiation safety management were configured as seven steps: step 1 is a production preparation step, step 2 is an RI production step, step 3 is a synthesis step, step 4 is a distribution step, step 5 is a quality control step, step 6 is a carriage container packing step, and step 7 is a transportation step. It was recognized that the distribution step was the most exposed as 15 subjects (62.5%), the items of 'the sanction and permission related works' and 'the guarantee of installation facilities and production equipment' were the most difficult as 9 subjects (37.5%), and in the trouble steps in such exposure, the item of 'the synthesis and distribution' steps were 4 times, respectively (30.8%). In the score of the behavior level in radiation safety managements, the minimum and maximum scores were 2.42 and 4.00, respectively, and the average score was 3.46 ± 0.47 out of 4. Prosperity and well-being programs in the behavior and job in radiation safety managements (r=0.529) represented a significant correlation statistically. In the drawing of a prediction model based on the factors that affected the behavior in radiation safety managements, general

  10. A prediction model for the radiation safety management behavior of medical cyclotrons

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ji Hye; Han, Eun Ok [Daegu Health College, Daegu (Korea, Republic of); Kim, Ssang Tae [CareCamp Inc., Seoul (Korea, Republic of)

    2008-06-15

    This study attempted to provide reference materials for improving the behavior level in radiation safety managements by drawing a prediction model that affects the radiation safety management behavior because the radiation safety management of medical Cyclotrons, which can be used to produce radioisotopes, is an important factor that protects radiation caused diseases not only for radiological operators but average users. In addition, this study obtained follows results through the investigation applied from January 2 to January 30, 2008 for the radiation safety managers employed in 24 authorized organizations, which have already installed Cyclotrons, through applying a specific form of questionnaire in which the validity was guaranteed by reference study, site investigation, and focus discussion by related experts. The radiation safety management were configured as seven steps: step 1 is a production preparation step, step 2 is an RI production step, step 3 is a synthesis step, step 4 is a distribution step, step 5 is a quality control step, step 6 is a carriage container packing step, and step 7 is a transportation step. It was recognized that the distribution step was the most exposed as 15 subjects (62.5%), the items of 'the sanction and permission related works' and 'the guarantee of installation facilities and production equipment' were the most difficult as 9 subjects (37.5%), and in the trouble steps in such exposure, the item of 'the synthesis and distribution' steps were 4 times, respectively (30.8%). In the score of the behavior level in radiation safety managements, the minimum and maximum scores were 2.42 and 4.00, respectively, and the average score was 3.46 {+-} 0.47 out of 4. Prosperity and well-being programs in the behavior and job in radiation safety managements (r=0.529) represented a significant correlation statistically. In the drawing of a prediction model based on the factors that affected the behavior in

  11. Predicted Rates of Secondary Malignancies From Proton Versus Photon Radiation Therapy for Stage I Seminoma

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Charles B., E-mail: csimone@alumni.upenn.edu [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Kramer, Kevin [Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland (United States); O' Meara, William P. [Division of Radiation Oncology, National Naval Medical Center, Bethesda, Maryland (United States); Bekelman, Justin E. [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); Belard, Arnaud [Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland (United States); McDonough, James [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); O' Connell, John [Radiation Oncology Service, Walter Reed Army Medical Center, Washington, DC (United States)

    2012-01-01

    Purpose: Photon radiotherapy has been the standard adjuvant treatment for stage I seminoma. Single-dose carboplatin therapy and observation have emerged as alternative options due to concerns for acute toxicities and secondary malignancies from radiation. In this institutional review board-approved study, we compared photon and proton radiotherapy for stage I seminoma and the predicted rates of excess secondary malignancies for both treatment modalities. Methods and Material: Computed tomography images from 10 consecutive patients with stage I seminoma were used to quantify dosimetric differences between photon and proton therapies. Structures reported to be at increased risk for secondary malignancies and in-field critical structures were contoured. Reported models of organ-specific radiation-induced cancer incidence rates based on organ equivalent dose were used to determine the excess absolute risk of secondary malignancies. Calculated values were compared with tumor registry reports of excess secondary malignancies among testicular cancer survivors. Results: Photon and proton plans provided comparable target volume coverage. Proton plans delivered significantly lower mean doses to all examined normal tissues, except for the kidneys. The greatest absolute reduction in mean dose was observed for the stomach (119 cGy for proton plans vs. 768 cGy for photon plans; p < 0.0001). Significantly more excess secondary cancers per 10,000 patients/year were predicted for photon radiation than for proton radiation to the stomach (4.11; 95% confidence interval [CI], 3.22-5.01), large bowel (0.81; 95% CI, 0.39-1.01), and bladder (0.03; 95% CI, 0.01-0.58), while no difference was demonstrated for radiation to the pancreas (0.02; 95% CI, -0.01-0.06). Conclusions: For patients with stage I seminoma, proton radiation therapy reduced the predicted secondary cancer risk compared with photon therapy. We predict a reduction of one additional secondary cancer for every 50 patients

  12. Predictive modelling for swallowing dysfunction after primary (chemo)radiation: results of a prospective observational study.

    Science.gov (United States)

    Christianen, Miranda E M C; Schilstra, Cornelis; Beetz, Ivo; Muijs, Christina T; Chouvalova, Olga; Burlage, Fred R; Doornaert, Patricia; Koken, Phil W; Leemans, C René; Rinkel, Rico N P M; de Bruijn, Marieke J; de Bock, G H; Roodenburg, Jan L N; van der Laan, Bernard F A M; Slotman, Ben J; Verdonck-de Leeuw, Irma M; Bijl, Hendrik P; Langendijk, Johannes A

    2012-10-01

    The purpose of this large multicentre prospective cohort study was to identify which dose volume histogram parameters and pre-treatment factors are most important to predict physician-rated and patient-rated radiation-induced swallowing dysfunction (RISD) in order to develop predictive models for RISD after curative (chemo) radiotherapy ((CH) RT). The study population consisted of 354 consecutive head and neck cancer patients treated with (CH) RT. The primary endpoint was grade 2 or more swallowing dysfunction according to the RTOG/EORTC late radiation morbidity scoring criteria at 6 months after (CH) RT. The secondary endpoints were patient-rated swallowing complaints as assessed with the EORTC QLQ-H&N35 questionnaire. To select the most predictive variables a multivariate logistic regression analysis with bootstrapping was used. At 6 months after (CH) RT the bootstrapping procedure revealed that a model based on the mean dose to the superior pharyngeal constrictor muscle (PCM) and mean dose to the supraglottic larynx was most predictive. For the secondary endpoints different predictive models were found: for problems with swallowing liquids the most predictive factors were the mean dose to the supraglottic larynx and radiation technique (3D-CRT versus IMRT). For problems with swallowing soft food the mean dose to the middle PCM, age (18-65 versus >65 years), tumour site (naso/oropharynx versus other sites) and radiation technique (3D-CRT versus IMRT) were the most predictive factors. For problems with swallowing solid food the most predictive factors were the mean dose to the superior PCM, the mean dose to the supraglottic larynx and age (18-65 versus >65 years). And for choking when swallowing the V60 of the oesophageal inlet muscle and the mean dose to the supraglottic larynx were the most predictive factors. Physician-rated and patient-rated RISD in head and neck cancer patients treated with (CH) RT cannot be predicted with univariate relationships between the

  13. DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Behne, Patrick Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-08

    The modeling of the detectability of special nuclear material (SNM) at ports and border crossings requires accurate knowledge of the background radiation at those locations. Background radiation originates from two main sources, cosmic and terrestrial. Cosmic background is produced by high-energy galactic cosmic rays (GCR) entering the atmosphere and inducing a cascade of particles that eventually impact the earth’s surface. The solar modulation potential represents one of the primary inputs to modeling cosmic background radiation. Usosokin et al. formally define solar modulation potential as “the mean energy loss [per unit charge] of a cosmic ray particle inside the heliosphere…” Modulation potential, a function of elevation, location, and time, shares an inverse relationship with cosmic background radiation. As a result, radiation detector thresholds require adjustment to account for differing background levels, caused partly by differing solar modulations. Failure to do so can result in higher rates of false positives and failed detection of SNM for low and high levels of solar modulation potential, respectively. This study focuses on solar modulation’s time dependence, and seeks the best method to predict modulation for future dates using Python. To address the task of predicting future solar modulation, we utilize both non-linear least squares sinusoidal curve fitting and cubic spline interpolation. This material will be published in transactions of the ANS winter meeting of November, 2016.

  14. A Neural Network Based Intelligent Predictive Sensor for Cloudiness, Solar Radiation and Air Temperature

    Science.gov (United States)

    Ferreira, Pedro M.; Gomes, João M.; Martins, Igor A. C.; Ruano, António E.

    2012-01-01

    Accurate measurements of global solar radiation and atmospheric temperature, as well as the availability of the predictions of their evolution over time, are important for different areas of applications, such as agriculture, renewable energy and energy management, or thermal comfort in buildings. For this reason, an intelligent, light-weight and portable sensor was developed, using artificial neural network models as the time-series predictor mechanisms. These have been identified with the aid of a procedure based on the multi-objective genetic algorithm. As cloudiness is the most significant factor affecting the solar radiation reaching a particular location on the Earth surface, it has great impact on the performance of predictive solar radiation models for that location. This work also represents one step towards the improvement of such models by using ground-to-sky hemispherical colour digital images as a means to estimate cloudiness by the fraction of visible sky corresponding to clouds and to clear sky. The implementation of predictive models in the prototype has been validated and the system is able to function reliably, providing measurements and four-hour forecasts of cloudiness, solar radiation and air temperature. PMID:23202230

  15. The use of normal tissue complication probability to predict radiation hepatitis

    International Nuclear Information System (INIS)

    Keum, Ki Chang; Seong, Jin Sil; Suh, Chang Ok; Lee, Sang Wook; Chung, Eun Ji; Shin, Hyun Soo; Kim, Gwi Eon

    2000-01-01

    correlated to predict a radiation hepatitis. The risk of radiation hepatitis was increased above the cut-off value. Therefore the NTCP seems to be used for predicting the radiation hepatitis

  16. Prevalence and Predicting Factors for Commonly Neglected Sexual Side Effects to External-Beam Radiation Therapy for Prostate Cancer.

    Science.gov (United States)

    Frey, Anders; Pedersen, Christian; Lindberg, Henriette; Bisbjerg, Rasmus; Sønksen, Jens; Fode, Mikkel

    2017-04-01

    Changes in sexual function other than erectile dysfunction are sparsely investigated after radiation therapy for prostate cancer. To investigate orgasmic dysfunction, urinary incontinence during sexual activity, changes in penile morphology, and sensory disturbances in the penis in patients with prostate cancer treated with external-beam radiation therapy (EBRT). In February 2015, men treated with EBRT at our center 3 months to 5 years previously (N = 519) received a study-specific questionnaire. This was developed from purpose-built questions and validated tools including the Erection Hardness Scale. All patients had received a radiation dose of 78 Gy. Androgen deprivation therapy was administered according to disease characteristics. Outcome measurements were prevalence rates and predictors of these side effects as identified by multivariate logistic regression analyses. One hundred nine patients were eligible (sexually active and had completed androgen deprivation therapy) for inclusion. Twenty-four percent reported anorgasmia, 44% reported a decreased intensity of their orgasms, and 40% reported that the time it took to reach orgasm had increased. Eleven percent reported anejaculation. Fifteen percent reported orgasm-associated pain. Only 4% reported urinary incontinence during sexual activity. Subjective penile length loss in excess of 1 cm was reported by 42%. Twelve percent reported an altered curvature of their penis after EBRT. Six percent reported painful erections. Twenty-seven percent reported decreased sensitivity in the penis after EBRT, 2% reported a cold sensation, and 2% reported paresthesia. Increasing time since final treatment increased the risk of penile sensory disturbances (odds ratio = 1.05; P = .028). Orgasmic dysfunction, changes in penile morphology, and sensory disturbances in the penis are common side effects of ERBT. Patients should be properly informed of the occurrence of these side effects before deciding which treatment to

  17. Real-Time Aircraft Cosmic Ray Radiation Exposure Predictions from the NAIRAS Model

    Science.gov (United States)

    Mertens, C. J.; Tobiska, W.; Kress, B. T.; Xu, X.

    2012-12-01

    The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a prototype operational model for predicting commercial aircraft radiation exposure from galactic and solar cosmic rays. NAIRAS predictions are currently streaming live from the project's public website, and the exposure rate nowcast is also available on the SpaceWx smartphone app for iPhone, IPad, and Android. Cosmic rays are the primary source of human exposure to high linear energy transfer radiation at aircraft altitudes, which increases the risk of cancer and other adverse health effects. Thus, the NAIRAS model addresses an important national need with broad societal, public health and economic benefits. There is also interest in extending NAIRAS to the LEO environment to address radiation hazard issues for the emerging commercial spaceflight industry. The processes responsible for the variability in the solar wind, interplanetary magnetic field, solar energetic particle spectrum, and the dynamical response of the magnetosphere to these space environment inputs, strongly influence the composition and energy distribution of the atmospheric ionizing radiation field. Real-time observations are required at a variety of locations within the geospace environment. The NAIRAS model is driven by real-time input data from ground-, atmospheric-, and space-based platforms. During the development of the NAIRAS model, new science questions and observational data gaps were identified that must be addressed in order to obtain a more reliable and robust operational model of atmospheric radiation exposure. The focus of this talk is to present the current capabilities of the NAIRAS model, discuss future developments in aviation radiation modeling and instrumentation, and propose strategies and methodologies of bridging known gaps in current modeling and observational capabilities.

  18. Artificial neural network optimisation for monthly average daily global solar radiation prediction

    International Nuclear Information System (INIS)

    Alsina, Emanuel Federico; Bortolini, Marco; Gamberi, Mauro; Regattieri, Alberto

    2016-01-01

    Highlights: • Prediction of the monthly average daily global solar radiation over Italy. • Multi-location Artificial Neural Network (ANN) model: 45 locations considered. • Optimal ANN configuration with 7 input climatologic/geographical parameters. • Statistical indicators: MAPE, NRMSE, MPBE. - Abstract: The availability of reliable climatologic data is essential for multiple purposes in a wide set of anthropic activities and operative sectors. Frequently direct measures present spatial and temporal lacks so that predictive approaches become of interest. This paper focuses on the prediction of the Monthly Average Daily Global Solar Radiation (MADGSR) over Italy using Artificial Neural Networks (ANNs). Data from 45 locations compose the multi-location ANN training and testing sets. For each location, 13 input parameters are considered, including the geographical coordinates and the monthly values for the most frequently adopted climatologic parameters. A subset of 17 locations is used for ANN training, while the testing step is against data from the remaining 28 locations. Furthermore, the Automatic Relevance Determination method (ARD) is used to point out the most relevant input for the accurate MADGSR prediction. The ANN best configuration includes 7 parameters, only, i.e. Top of Atmosphere (TOA) radiation, day length, number of rainy days and average rainfall, latitude and altitude. The correlation performances, expressed through statistical indicators as the Mean Absolute Percentage Error (MAPE), range between 1.67% and 4.25%, depending on the number and type of the chosen input, representing a good solution compared to the current standards.

  19. Rockburst Disaster Prediction of Isolated Coal Pillar by Electromagnetic Radiation Based on Frictional Effect

    Science.gov (United States)

    Zhao, Tongbin; Yin, Yanchun; Xiao, Fukun; Tan, Yunliang; Zou, Jianchao

    2014-01-01

    Based on the understanding that charges generated during coal cracking are due to coal particle friction, a microstructure model was developed by considering four different variation laws of friction coefficient. Firstly, the frictional energy release of coal sample during uniaxial compressive tests was investigated and discussed. Then electromagnetic radiation method was used to predict the potential rockburst disaster in isolated coal pillar mining face, Muchengjian Colliery. The results indicate that the friction coefficient of coal particles decreases linearly with the increase of axial loading force. In predicting the strain-type rockburst, the high stress state of coal must be closely monitored. Field monitoring shows that electromagnetic radiation signal became abnormal before the occurrence of rockburst during isolated coal pillar mining. Furthermore, rockburst tends to occur at the early and ending stages of isolated coal pillar extraction. Mine-site investigation shows the occurrence zone of rockburst is consistent with the prediction, proving the reliability of the electromagnetic radiation method to predict strain-type rockburst disaster. PMID:25054186

  20. Rockburst Disaster Prediction of Isolated Coal Pillar by Electromagnetic Radiation Based on Frictional Effect

    Directory of Open Access Journals (Sweden)

    Tongbin Zhao

    2014-01-01

    Full Text Available Based on the understanding that charges generated during coal cracking are due to coal particle friction, a microstructure model was developed by considering four different variation laws of friction coefficient. Firstly, the frictional energy release of coal sample during uniaxial compressive tests was investigated and discussed. Then electromagnetic radiation method was used to predict the potential rockburst disaster in isolated coal pillar mining face, Muchengjian Colliery. The results indicate that the friction coefficient of coal particles decreases linearly with the increase of axial loading force. In predicting the strain-type rockburst, the high stress state of coal must be closely monitored. Field monitoring shows that electromagnetic radiation signal became abnormal before the occurrence of rockburst during isolated coal pillar mining. Furthermore, rockburst tends to occur at the early and ending stages of isolated coal pillar extraction. Mine-site investigation shows the occurrence zone of rockburst is consistent with the prediction, proving the reliability of the electromagnetic radiation method to predict strain-type rockburst disaster.

  1. Study of radiative leptonic events with hard photons and search for excited charged leptons at $\\sqrt{s}$ = 130-136 GeV

    CERN Document Server

    Abreu, P; Adye, T; Agasi, E; Aleksan, Roy; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbi, M S; Barbiellini, Guido; Bardin, Dimitri Yuri; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Berggren, M; Bertini, D; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Buys, A; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Durand, J D; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Fenyuk, A; Ferrer, A; Fichet, S; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gibbs, M; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Last, I; Laugier, J P; Lauhakangas, R; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Libby, J; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Merk, M; Meroni, C; Meyer, S; Meyer, W T; Myagkov, A; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Novák, M; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Pindo, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sahr, O; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Serbelloni, L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Solokov, A; Sosnowski, R; Souza-Santos, D; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stevenson, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Thomas, J; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Todorova, S; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zucchelli, G C; Zumerle, G

    1996-01-01

    During the last 1995 data acquisition period at LEP, the DELPHI experiment collected an integrated luminosity of $5.9$ pb$^{-1}$ at centre-of-mass energies of 130 GeV and 136 GeV. Radiative leptonic events ($e, \\mu, \\tau$) with high energy photons were studied and compared to Standard Model predictions. The data were used to search for charged excited leptons decaying through an electromagnetic transition. No significant signal was found. From the search for pair produced excited leptons, the limits $m_{e^*} > 62.5$ GeV/$c^2$, $m_{\\mu^*} > 62.6$ GeV/$c^2$ and $m_{\\tau^*} > 62.2$ GeV/$c^2$ at 95\\% confidence level were established. For single excited lepton production, upper limits on the ratio $\\lambda/m_{\\ell^*}$ of the coupling of the excited charged lepton to its mass were derived.

  2. A comparison of field-only electronic portal imaging hard copies with double exposure port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center

    International Nuclear Information System (INIS)

    Hatherly, Kay; Smylie, Josephine; Rodger, Alan

    1999-01-01

    Purpose: To determine in which treatment sites field-only hard copy electronic portal images (EPI) captured during a treatment exposure could replace traditional double exposed port films in a busy radiation oncology department. Methods and Materials: The three linear accelerators in the William Buckland Radiotherapy Centre (WBRC) at the Alfred Hospital in Melbourne are each equipped with an electronic portal imaging device (EPID). These devices can be used daily on all patients where the treatment fields are within the size constraint of the cassette, for example, less than 25 x 25 cm. Port films using radiographic film in hard cassettes were previously considered the standard method of field placement verification. After the radiation therapists were trained in all program aspects of capturing, enhancing, and producing hard copies of EPIs, a study was developed to evaluate the possibility of replacing port films with EPI hard copies within the established departmental procedures. Comparison of EPI hard copy with the simulator film and the port film of the same field was carried out by the radiation oncologist specialists. Seventy-eight comparison sets were generated and grouped into seven anatomical regions for evaluation by the radiation oncologist specialist responsible for each particular region. The outcome decision was the preferred imaging option. Where no preference was stated, EPI became the modality of choice, as it increased the efficiency of work practice. Results: The results indicate that field-only EPI can be considered to be at least as clinically useful for treatment verification in the following sites: breast, chest, hip, spine, and large pelvic fields. Port films using a standard, double exposure technique were considered necessary for partial brain fields, small pelvis fields, extremities, and radical head and neck fields. Conclusion: The quality of field-only images captured using an EPID has been favorably assessed to be equivalent to, or an

  3. Does Unintentional Splenic Radiation Predict Outcomes After Pancreatic Cancer Radiation Therapy?

    International Nuclear Information System (INIS)

    Chadha, Awalpreet S.; Liu, Guan; Chen, Hsiang-Chun; Das, Prajnan; Minsky, Bruce D.; Mahmood, Usama; Delclos, Marc E.; Suh, Yelin; Sawakuchi, Gabriel O.; Beddar, Sam; Katz, Matthew H.; Fleming, Jason B.; Javle, Milind M.; Varadhachary, Gauri R.; Wolff, Robert A.; Crane, Christopher H.; Wang, Xuemei; Thames, Howard; Krishnan, Sunil

    2017-01-01

    Purpose: To determine whether severity of lymphopenia is dependent on radiation dose and fractional volume of spleen irradiated unintentionally during definitive chemoradiation (CRT) in patients with locally advanced pancreatic cancer (LAPC). Methods: 177 patients with LAPC received induction chemotherapy (mainly gemcitabine-based regimens) followed by CRT (median 50.4 Gy with concurrent capecitabine) from January 2006 to December 2012. Absolute lymphocyte count (ALC) was recorded at baseline, before CRT, and 2 to 10 weeks after CRT. Splenic dose-volume histogram (DVH) parameters were reported as mean splenic dose (MSD) and percentage of splenic volume receiving at least 5- (V5), 10- (V10), 15- (V15), and 20-Gy (V20) dose. Overall survival (OS) was analyzed with use of the Cox model, and development of post-CRT severe lymphopenia (ALC <0.5 K/UL) was assessed by multivariate logistic regression with use of baseline and treatment factors. Results: The median post-CRT ALC (0.68 K/UL; range, 0.13-2.72) was significantly lower than both baseline ALC (1.42 K/UL; range, 0.34-3.97; P<.0001) and pre-CRT ALC (1.32 K/UL, range 0.36-4.82; P<.0001). Post-CRT ALC <0.5 K/UL was associated with inferior OS on univariate analysis (median, 11.1 vs 15.3 months; P=.01) and multivariate analysis (hazard ratio = 1.66, P=.01). MSD (9.8 vs 6 Gy, P=.03), median V10 (32.6 vs 16%, P=.04), V15 (23.2 vs 9.5%, P=.03), and V20 (15.4 vs 4.6%, P=.02) were significantly higher in patients with severe lymphopenia than in those without. On multivariate analysis, postinduction lymphopenia (P<.001; odds ratio [OR] = 5.25) and MSD (P=.002; OR= 3.42) were independent predictors for the development of severe post-CRT lymphopenia. Conclusion: Severe post-CRT lymphopenia is an independent predictor of poor OS in LAPC patients receiving CRT. Higher splenic doses increase the risk for the development of severe post-CRT lymphopenia. When clinically indicated, assessment of splenic DVHs before the

  4. Does Unintentional Splenic Radiation Predict Outcomes After Pancreatic Cancer Radiation Therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Chadha, Awalpreet S.; Liu, Guan [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chen, Hsiang-Chun [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Das, Prajnan; Minsky, Bruce D.; Mahmood, Usama; Delclos, Marc E. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Suh, Yelin [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sawakuchi, Gabriel O. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas (United States); Beddar, Sam [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Katz, Matthew H.; Fleming, Jason B. [Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Javle, Milind M.; Varadhachary, Gauri R.; Wolff, Robert A. [Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Crane, Christopher H. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang, Xuemei [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Thames, Howard [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Krishnan, Sunil, E-mail: skrishnan@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2017-02-01

    Purpose: To determine whether severity of lymphopenia is dependent on radiation dose and fractional volume of spleen irradiated unintentionally during definitive chemoradiation (CRT) in patients with locally advanced pancreatic cancer (LAPC). Methods: 177 patients with LAPC received induction chemotherapy (mainly gemcitabine-based regimens) followed by CRT (median 50.4 Gy with concurrent capecitabine) from January 2006 to December 2012. Absolute lymphocyte count (ALC) was recorded at baseline, before CRT, and 2 to 10 weeks after CRT. Splenic dose-volume histogram (DVH) parameters were reported as mean splenic dose (MSD) and percentage of splenic volume receiving at least 5- (V5), 10- (V10), 15- (V15), and 20-Gy (V20) dose. Overall survival (OS) was analyzed with use of the Cox model, and development of post-CRT severe lymphopenia (ALC <0.5 K/UL) was assessed by multivariate logistic regression with use of baseline and treatment factors. Results: The median post-CRT ALC (0.68 K/UL; range, 0.13-2.72) was significantly lower than both baseline ALC (1.42 K/UL; range, 0.34-3.97; P<.0001) and pre-CRT ALC (1.32 K/UL, range 0.36-4.82; P<.0001). Post-CRT ALC <0.5 K/UL was associated with inferior OS on univariate analysis (median, 11.1 vs 15.3 months; P=.01) and multivariate analysis (hazard ratio = 1.66, P=.01). MSD (9.8 vs 6 Gy, P=.03), median V10 (32.6 vs 16%, P=.04), V15 (23.2 vs 9.5%, P=.03), and V20 (15.4 vs 4.6%, P=.02) were significantly higher in patients with severe lymphopenia than in those without. On multivariate analysis, postinduction lymphopenia (P<.001; odds ratio [OR] = 5.25) and MSD (P=.002; OR= 3.42) were independent predictors for the development of severe post-CRT lymphopenia. Conclusion: Severe post-CRT lymphopenia is an independent predictor of poor OS in LAPC patients receiving CRT. Higher splenic doses increase the risk for the development of severe post-CRT lymphopenia. When clinically indicated, assessment of splenic DVHs before the

  5. The Multi-Layered Perceptrons Neural Networks for the Prediction of Daily Solar Radiation

    OpenAIRE

    Radouane Iqdour; Abdelouhab Zeroual

    2007-01-01

    The Multi-Layered Perceptron (MLP) Neural networks have been very successful in a number of signal processing applications. In this work we have studied the possibilities and the met difficulties in the application of the MLP neural networks for the prediction of daily solar radiation data. We have used the Polack-Ribière algorithm for training the neural networks. A comparison, in term of the statistical indicators, with a linear model most used in literature, is also perfo...

  6. A new Predictive Model for Relativistic Electrons in Outer Radiation Belt

    Science.gov (United States)

    Chen, Y.

    2017-12-01

    Relativistic electrons trapped in the Earth's outer radiation belt present a highly hazardous radiation environment for spaceborne electronics. These energetic electrons, with kinetic energies up to several megaelectron-volt (MeV), manifest a highly dynamic and event-specific nature due to the delicate interplay of competing transport, acceleration and loss processes. Therefore, developing a forecasting capability for outer belt MeV electrons has long been a critical and challenging task for the space weather community. Recently, the vital roles of electron resonance with waves (including such as chorus and electromagnetic ion cyclotron) have been widely recognized; however, it is still difficult for current diffusion radiation belt models to reproduce the behavior of MeV electrons during individual geomagnetic storms, mainly because of the large uncertainties existing in input parameters. In this work, we expanded our previous cross-energy cross-pitch-angle coherence study and developed a new predictive model for MeV electrons over a wide range of L-shells inside the outer radiation belt. This new model uses NOAA POES observations from low-Earth-orbits (LEOs) as inputs to provide high-fidelity nowcast (multiple hour prediction) and forecast (> 1 day prediction) of the energization of MeV electrons as well as the evolving MeV electron distributions afterwards during storms. Performance of the predictive model is quantified by long-term in situ data from Van Allen Probes and LANL GEO satellites. This study adds new science significance to an existing LEO space infrastructure, and provides reliable and powerful tools to the whole space community.

  7. A novel prediction method of vibration and acoustic radiation for rectangular plate with particle dampers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqiang; Wu, Chengjun [Xi' an Jiaotong University, Xi' an (China)

    2016-03-15

    Particle damping technology is widely used in mechanical and structural systems or civil engineering to reduce vibration and suppress noise as a result of its high efficiency, simplicity and easy implementation, low cost, and energy-saving characteristic without the need for any auxiliary power equipment. Research on particle damping theory has focused on the vibration response of the particle damping structure, but the acoustic radiation of the particle damping structure is rarely investigated. Therefore, a feasible modeling method to predict the vibration response and acoustic radiation of the particle damping structure is desirable to satisfy the actual requirements in industrial practice. In this paper, a novel simulation method based on multiphase flow theory of gas particle by COMSOL multiphysics is developed to study the vibration and acoustic radiation characteristics of a cantilever rectangular plate with Particle dampers (PDs). The frequency response functions and scattered far-field sound pressure level of the plate without and with PDs under forced vibration are predicted, and the predictions agree well with the experimental results. Results demonstrate that the added PDs have a significant effect on vibration damping and noise reduction for the primary structure. The presented work in this paper shows that the theoretical work is valid, which can provide important theoretical guidance for low-noise optimization design of particle damping structure. This model also has an important reference value for the noise control of this kind of structure.

  8. Individual response to ionising radiation: What predictive assay(s) to choose?

    International Nuclear Information System (INIS)

    Granzotto, A.; Viau, M.; Devic, C.; Maalouf, M.; Thomas, Ch.; Vogin, G.; Foray, N.; Granzotto, A.; Vogin, G.; Balosso, J.; Joubert, A.; Maalouf, M.; Vogin, G.; Colin, C.; Malek, K.; Balosso, J.; Colin, C.

    2011-01-01

    Individual response to ionizing radiation is an important information required to apply an efficient radiotherapy treatment against tumour and to avoid any adverse effects in normal tissues. In 1981, Fertil and Malaise have demonstrated that the post-irradiation local tumor control determined in vivo is correlated with clonogenic cell survival assessed in vitro. Furthermore, these authors have reminded the relevance of the concept of intrinsic radiosensitivity that is specific to each individual organ (Fertil and Malaise, 1981) [1]. To date, since clonogenicity assays are too time-consuming and do not provide any other molecular information, a plethora of research groups have attempted to determine the molecular bases of intrinsic radiosensitivity in order to propose reliable and faster predictive assays. To this aim, several approaches have been developed. Notably, the recent revolution in genomic and proteomics technologies is providing a considerable number of data but their link with radiosensitivity still remains to be elucidated. On another hand, the systematic screening of some candidate genes potentially involved in the radiation response is highlighting the complexity of the molecular and cellular mechanisms of DNA damage sensing and signalling and shows that an abnormal radiation response is not necessarily due to the impairment of one single protein. Finally, more modest approaches consisting in focusing some specific functions of DNA repair seem to provide more reliable clues to predict over-acute reactions caused by radiotherapy. In this review, we endeavored to analyse the contributions of these major approaches to predict human radiosensitivity. (authors)

  9. Applications Of Monte Carlo Radiation Transport Simulation Techniques For Predicting Single Event Effects In Microelectronics

    International Nuclear Information System (INIS)

    Warren, Kevin; Reed, Robert; Weller, Robert; Mendenhall, Marcus; Sierawski, Brian; Schrimpf, Ronald

    2011-01-01

    MRED (Monte Carlo Radiative Energy Deposition) is Vanderbilt University's Geant4 application for simulating radiation events in semiconductors. Geant4 is comprised of the best available computational physics models for the transport of radiation through matter. In addition to basic radiation transport physics contained in the Geant4 core, MRED has the capability to track energy loss in tetrahedral geometric objects, includes a cross section biasing and track weighting technique for variance reduction, and additional features relevant to semiconductor device applications. The crucial element of predicting Single Event Upset (SEU) parameters using radiation transport software is the creation of a dosimetry model that accurately approximates the net collected charge at transistor contacts as a function of deposited energy. The dosimetry technique described here is the multiple sensitive volume (MSV) model. It is shown to be a reasonable approximation of the charge collection process and its parameters can be calibrated to experimental measurements of SEU cross sections. The MSV model, within the framework of MRED, is examined for heavy ion and high-energy proton SEU measurements of a static random access memory.

  10. The relationship of animal experiments in predicting the effects on intrauterine radiation effects in the human

    International Nuclear Information System (INIS)

    Brent, R.L.; Beckmann, D.A.; Jensh, R.P.; Thomas Jefferson Univ., Philadelphia, PA

    1986-01-01

    Although animal studies cannot be used to predict human disease, they can be utilized to study the mechanisms and the risk of radiation embryological effects reported in humans. The radiation embryological effects dealing with sterility, tumor development, life span studies and certain aspects of central nervous system functions cannot be so evaluated because of marked discordance in development or function between the rodent and human. It is important to recognize that, although the effects are markedly different, all stages of gestation have pathological effects following intrauterine radiation. There is no stage that will not be affected by 50 cGy: death in the preimplantation period; major malformations during early organogenesis; minor malformations during later organogenesis; histogenetic depletion, disorganization and cell depletion in midgestation; and cell depletion during the later part of gestation. The threshold dose for each of these effects is approximately 20 cGy, except during late gestation when permanent effects may not be produced at this low dose. All radiation embryological effects are multicellular phenomenona and, since it is unlikely that they are stochastic phenomena, the risks are not linearly related to radiation dose. The only exception may be the lethal effect produced on the first day of gestation. The present maximum permissible exposure of 0.5 cGy per years is appropriate for women of reproductive age exposed to radiation in the work place. Exposures from diagnostic radiation below 5 cGy present such a small or non-measurable risk, that counselors can support the continuation of wanted pregnancies. Inadvertant or medically necessary radiographic examinations present no greater concern whether in the first or second half of the menstrual cycle since pre-ovulation exposures or post-conception exposures before the first missed menstrual period of 5 cGy or less present a similar minimal risk. (orig.)

  11. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Nina N. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Harvard Medical School, Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Niemierko, Andrzej [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); Larvie, Mykol [Harvard Medical School, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts (United States); Curtin, Hugh [Harvard Medical School, Department of Radiology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Loeffler, Jay S. [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States); McKenna, Michael J. [Harvard Medical School, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-05-01

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  12. Prediction of the performance of an ion chamber amplifier under γ radiation

    International Nuclear Information System (INIS)

    Agarwal, Vivek; Sundarsingh, V.P.; Ramachandran, V.

    2005-01-01

    The ion chamber amplifier (ICA) plays a major role in the proper functioning of a nuclear reactor as it monitors the radiations from the nuclear reactor by measuring the ionic activity inside the ion chamber. The signal conditioning circuitry of the ICA detects and conditions the weak ionic currents coming from the ion chamber dome. Degradation in the performance of the semiconductor devices used in this part of the ICA, can lead to inaccurate monitoring of the reactor operation, resulting in a possible catastrophe due to malfunction. Further, the response of the ICA under irradiation also depends upon the strength of the input signal (ionic) current it is required to handle. The active devices used in the ICA under study are operational amplifiers (Op-Amps) such as DN8500A and OPA111, instrumentation amplifier INA101, transistor 2N2920A and a voltage reference device, AD584. Since these devices may be sensitive to radiation, one must know their radiation behaviour so that the performance of the ICA can be predicted. This paper examines the performance of the ICA by characterising the radiation profiles of its vital components, viz. the Op-Amps, instrumentation amplifiers, transistors, etc. by monitoring their parametric changes on-line, i.e. when the source is on, and the devices are biased. The simulation runs involve the simulation of the entire ICA circuitry using the changed values of the vital parameters such as input bias current and input offset voltage. The main advantage of this method is that it obviates irradiating the whole ICA circuit to study its irradiation performance, and simulates an environment of radiation leakage around the ICA. Based on this study, results are presented to predict the performance of the ICA

  13. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    International Nuclear Information System (INIS)

    Niu, Nina N.; Niemierko, Andrzej; Larvie, Mykol; Curtin, Hugh; Loeffler, Jay S.; McKenna, Michael J.; Shih, Helen A.

    2014-01-01

    Purpose: Vestibular schwannomas (VS) are often followed without initial therapeutic intervention because many tumors do not grow and radiation therapy is associated with potential adverse effects. In an effort to determine whether maximizing initial surveillance predicts for later treatment response, the predictive value of preirradiation growth rate of VS on response to radiation therapy was assessed. Methods and Materials: Sixty-four patients with 65 VS were treated with single-fraction stereotactic radiation surgery or fractionated stereotactic radiation therapy. Pre- and postirradiation linear expansion rates were estimated using volumetric measurements on sequential magnetic resonance images (MRIs). In addition, postirradiation tumor volume change was classified as demonstrating shrinkage (ratio of volume on last follow-up MRI to MRI immediately preceding irradiation <80%), stability (ratio 80%-120%), or expansion (ratio >120%). The median pre- and postirradiation follow-up was 20.0 and 27.5 months, respectively. Seven tumors from neurofibromatosis type 2 (NF2) patients were excluded from statistical analyses. Results: In the 58 non-NF2 patients, there was a trend of correlation between pre- and postirradiation volume change rates (slope on linear regression, 0.29; P=.06). Tumors demonstrating postirradiation expansion had a median preirradiation growth rate of 89%/year, and those without postirradiation expansion had a median preirradiation growth rate of 41%/year (P=.02). As the preirradiation growth rate increased, the probability of postirradiation expansion also increased. Overall, 24.1% of tumors were stable, 53.4% experienced shrinkage, and 22.5% experienced expansion. Predictors of no postirradiation tumor expansion included no prior surgery (P=.01) and slower tumor growth rate (P=.02). The control of tumors in NF2 patients was only 43%. Conclusions: Radiation therapy is an effective treatment for VS, but tumors that grow quickly preirradiation may be

  14. Prediction of shock-layer ultraviolet radiation for hypersonic vehicles in near space

    Directory of Open Access Journals (Sweden)

    Niu Qinglin

    2016-10-01

    Full Text Available A systemic and validated model was developed to predict ultraviolet spectra features from the shock layer of near-space hypersonic vehicles in the “solar blind” band region. Computational procedures were performed with 7-species thermal non-equilibrium fluid mechanics, finite rate chemistry, and radiation calculations. The thermal non-equilibrium flow field was calculated with a two-temperature model by the finite volume technique and verified against the bow-shock ultra-violet (BSUV flight experiments. The absorption coefficient of the mixture gases was evaluated with a line-by-line method and validated through laboratory shock tube measurements. Using the line of sight (LOS method, radiation was calculated from three BSUV flights at altitudes of 38, 53.5 and 71 km. The investigation focused on the level and structure of ultraviolet spectra radiated from a NO band system in wavelengths of 200–400 nm. Results predicted by the current model show qualitative spatial agreement with the measured data. At a velocity of 3.5 km/s (about Mach 11, the peak absolute intensity at an altitude of 38 km is two orders of magnitude higher than that at 53.5 km. Under the same flight conditions, the spectra structures have quite a similar distribution at different viewing angles. The present computational model performs well in the prediction of the ultraviolet spectra emitted from the shock layer and will contribute to the investigation and analysis of radiative features of hypersonic vehicles in near space.

  15. A hybrid numerical prediction scheme for solar radiation estimation in un-gauged catchments.

    Science.gov (United States)

    Shamim, M. A.; Bray, M.; Ishak, A. M.; Remesan, R.; Han, D.

    2009-09-01

    The importance of solar radiation on earth's surface is depicted in its wide range of applications in the fields of meteorology, agricultural sciences, engineering, hydrology, crop water requirements, climatic changes and energy assessment. It is quite random in nature as it has to go through different processes of assimilation and dispersion while on its way to earth. Compared to other meteorological parameters, solar radiation is quite infrequently measured, for example, the worldwide ratio of stations collecting solar radiation to those collecting temperature is 1:500 (Badescu, 2008). Researchers, therefore, have to rely on indirect techniques of estimation that include nonlinear models, artificial intelligence (e.g. neural networks), remote sensing and numerical weather predictions (NWP). This study proposes a hybrid numerical prediction scheme for solar radiation estimation in un-gauged catchments. It uses the PSU/NCAR's Mesoscale Modelling system (MM5) (Grell et al., 1995) to parameterise the cloud effect on extraterrestrial radiation by dividing the atmosphere into four layers of very high (6-12 km), high (3-6 km), medium (1.5-3) and low (0-1.5) altitudes from earth. It is believed that various cloud forms exist within each of these layers. An hourly time series of upper air pressure and relative humidity data sets corresponding to all of these layers is determined for the Brue catchment, southwest UK, using MM5. Cloud Index (CI) was then determined using (Yang and Koike, 2002): 1 p?bi [ (Rh - Rh )] ci =------- max 0.0,---------cri dp pbi - ptipti (1- Rhcri) where, pbi and pti represent the air pressure at the top and bottom of each layer and Rhcri is the critical value of relative humidity at which a certain cloud type is formed. Output from a global clear sky solar radiation model (MRM v-5) (Kambezidis and Psiloglu, 2008) is used along with meteorological datasets of temperature and precipitation and astronomical information. The analysis is aided by the

  16. The HIRLAM fast radiation scheme for mesoscale numerical weather prediction models

    Science.gov (United States)

    Rontu, Laura; Gleeson, Emily; Räisänen, Petri; Pagh Nielsen, Kristian; Savijärvi, Hannu; Hansen Sass, Bent

    2017-07-01

    This paper provides an overview of the HLRADIA shortwave (SW) and longwave (LW) broadband radiation schemes used in the HIRLAM numerical weather prediction (NWP) model and available in the HARMONIE-AROME mesoscale NWP model. The advantage of broadband, over spectral, schemes is that they can be called more frequently within the model, without compromising on computational efficiency. In mesoscale models fast interactions between clouds and radiation and the surface and radiation can be of greater importance than accounting for the spectral details of clear-sky radiation; thus calling the routines more frequently can be of greater benefit than the deterioration due to loss of spectral details. Fast but physically based radiation parametrizations are expected to be valuable for high-resolution ensemble forecasting, because as well as the speed of their execution, they may provide realistic physical perturbations. Results from single-column diagnostic experiments based on CIRC benchmark cases and an evaluation of 10 years of radiation output from the FMI operational archive of HIRLAM forecasts indicate that HLRADIA performs sufficiently well with respect to the clear-sky downwelling SW and longwave LW fluxes at the surface. In general, HLRADIA tends to overestimate surface fluxes, with the exception of LW fluxes under cold and dry conditions. The most obvious overestimation of the surface SW flux was seen in the cloudy cases in the 10-year comparison; this bias may be related to using a cloud inhomogeneity correction, which was too large. According to the CIRC comparisons, the outgoing LW and SW fluxes at the top of atmosphere are mostly overestimated by HLRADIA and the net LW flux is underestimated above clouds. The absorption of SW radiation by the atmosphere seems to be underestimated and LW absorption seems to be overestimated. Despite these issues, the overall results are satisfying and work on the improvement of HLRADIA for the use in HARMONIE-AROME NWP system

  17. Location of subventricular zone recurrence and its radiation dose predicts survival in patients with glioblastoma.

    Science.gov (United States)

    Weinberg, Brent D; Boreta, Lauren; Braunstein, Steve; Cha, Soonmee

    2018-07-01

    Glioblastomas are aggressive brain tumors that frequently recur in the subventricular zone (SVZ) despite maximal treatment. The purpose of this study was to evaluate imaging patterns of subventricular progression and impact of recurrent subventricular tumor involvement and radiation dose to patient outcome. Retrospective review of 50 patients diagnosed with glioblastoma and treated with surgery, radiation, and concurrent temozolomide from January 2012 to June 2013 was performed. Tumors were classified based on location, size, and cortical and subventricular zone involvement. Survival was compared based on recurrence type, distance from the initial enhancing tumor (local ≤ 2 cm, distant > 2 cm), and the radiation dose at the recurrence site. Progression of enhancing subventricular tumor was common at both local (58%) and distant (42%) sites. Median survival was better after local SVZ recurrence than distant SVZ recurrence (8.7 vs. 4.3 months, p = 0.04). Radiation doses at local SVZ recurrence sites recurrence averaged 57.0 ± 4.0 Gy compared to 44.7 ± 6.7 Gy at distant SVZ recurrence sites (p = 0.008). Distant subventricular progression at a site receiving ≤ 45 Gy predicted worse subsequent survival (p = 0.05). Glioblastomas frequently recurred in the subventricular zone, and patient survival was worse when enhancing tumor occurred at sites that received lower radiation doses. This recurrent disease may represent disease undertreated at the time of diagnosis, and further study is needed to determine if improved treatment strategies, such as including the subventricular zone in radiation fields, could improve clinical outcomes.

  18. Developing a theoretical predictive model for cellular response to combined actions of low radiation and hyperthermia

    International Nuclear Information System (INIS)

    Jin Kyu Kim; Petin, V.G.; Mishra, K.P.

    2007-01-01

    Complete text of publication follows. Background: Organisms in their living environment are not exposed to merely a single stress agent. Several factors such as radiation and heat may simultaneously exert their stressful effect to the organisms. The combined exposure to two stressors can result in an enhanced effect that would be expected from the addition of the separate exposures to individual agents. Objective: This study has been undertaken to develop a theoretical model for assessment of combined effects of low dose radiation and mild heat for predictive cellular response assay. Rationale: Present study was motivated from the belief that synergism may occur in terms of lethal lesions arising from the interaction of non-lethal sub-lesions induced by individual agents. The sub-lesions induced by each agent may be negligible or undetectable. But, there exists a possibility of some cross talk between sublesions produced by radiation and heat. These processes may reflect the real mechanisms for inflicting the lethal damage by otherwise ignorable or undetectable insults to exposed organisms. Results: A theoretically developed mathematical model of the synergy was formulated which was tested for validation on the experimental data. The model predictions fairly closely corresponded with several experimental results. .The significance of synergistic effects for radiation biology has been demonstrated. A number of common peculiarities of synergistic interactions were found to play their roles. A unified biophysical concept for synergistic interaction has been suggested. Conclusions: For a constant dose rate, synergistic interaction between radiation and hyperthermia especially at low intensity is realized only within a certain range of temperature, independently of the target object analyzed. For temperatures below the range, the synergistic effect was not observed and cell killing was mainly determined by the damage induced by ionizing radiation. On the contrary, the

  19. Stochastic Predictions of Cell Kill During Stereotactic Ablative Radiation Therapy: Do Hypoxia and Reoxygenation Really Matter?

    Energy Technology Data Exchange (ETDEWEB)

    Harriss-Phillips, Wendy M., E-mail: wharrphil@gmail.com [Department of Medical Physics, Royal Adelaide Hospital, Adelaide, South Australia (Australia); School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia (Australia); Bezak, Eva [School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia (Australia); International Centre for Allied Health Evidence, University of South Australia, Adelaide, South Australia (Australia); Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia (Australia); Potter, Andrew [Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, South Australia (Australia); Adelaide Radiotherapy Centre, Genesis CancerCare, Adelaide, South Australia (Australia)

    2016-07-15

    Purpose: To simulate stereotactic ablative radiation therapy on hypoxic and well-oxygenated in silico tumors, incorporating probabilistic parameter distributions and linear-quadratic versus linear-quadratic-cubic methodology and the evaluation of optimal fractionation schemes using biological effective dose (BED{sub α/β=10} {sub or} {sub 3}) comparisons. Methods and Materials: A temporal tumor growth and radiation therapy algorithm simulated high-dose external beam radiation therapy using stochastic methods. Realistic biological proliferative cellular hierarchy and pO{sub 2} histograms were incorporated into the 10{sup 8}-cell tumor model, with randomized radiation therapy applied during continual cell proliferation and volume-based gradual tumor reoxygenation. Dose fractions ranged from 6-35 Gy, with predictive outcomes presented in terms of the total doses (converted to BED) required to eliminate all cells that could potentially regenerate the tumor. Results: Well-oxygenated tumor control BED{sub 10} outcomes were not significantly different for high-dose versus conventional radiation therapy (BED{sub 10}: 79-84 Gy; Equivalent Dose in 2 Gy fractions with α/β of 10: 66-70 Gy); however, total treatment times decreased from 7 down to 1-3 weeks. For hypoxic tumors, an additional 28 Gy (51 Gy BED{sub 10}) was required, with BED{sub 10} increasing with dose per fraction due to wasted dose in the final fraction. Fractions of 9 Gy compromised well for total treatment time and BED, with BED{sub 10}:BED{sub 3} of 84:176 Gy for oxic and 132:278 Gy for non-reoxygenating hypoxic tumors. Initial doses of 12 Gy followed by 6 Gy further increased the therapeutic ratio. When delivering ≥9 Gy per fraction, applying reoxygenation and/or linear-quadratic-cubic cell survival both affected tumor control doses by a significant 1-2 fractions. Conclusions: The complex temporal dynamics of tumor oxygenation combined with probabilistic cell kinetics in the modeling of

  20. Hardness ratio evolutionary curves of gamma-ray bursts expected by the curvature effect

    International Nuclear Information System (INIS)

    Qin, Y.-P.; Su, C.-Y.; Fan, J. H.; Gupta, A. C.

    2006-01-01

    We have investigated the gamma-ray bursts (GRBs) pulses with a fast rise and an exponential decay phase, assumed to arise from relativistically expending fireballs, and found that the curvature effect influences the evolutionary curve of the corresponding hardness ratio (hereafter HRC). We find, due to the curvature effect, the evolutionary curve of the pure hardness ratio (when the background count is not included) would peak at the very beginning of the curve, and then would undergo a drop-to-rise-to-decay phase. In the case of the raw hardness ratio (when the background count is included), the curvature effect would give rise to several types of evolutionary curve, depending on the hardness of a burst. For a soft burst, an upside down pulse of its raw HRC would be observed; for a hard burst, its raw HRC shows a pulselike profile with a sinkage in its decaying phase; for a very hard burst, the raw HRC possesses a pulselike profile without a sinkage in its decaying phase. For a pulselike raw HRC as shown in the case of the hard and very hard bursts, its peak would appear in advance of that of the corresponding light curve, which was observed previously in some GRBs. For illustration, we have studied here the HRC of GRB 920216, GRB 920830, and GRB 990816 in detail. The features of the raw HRC expected in the hard burst are observed in these bursts. A fit to the three bursts shows that the curvature effect alone could indeed account for the predicted characteristics of HRCs. In addition, we find that the observed hardness ratio tends to be harder at the beginning of the pulses than what the curvature effect could predict and be softer at the late time of the pulses. We believe this is an evidence showing the existence of intrinsic hard-to-soft radiation which might be due to the acceleration-to-deceleration mode of shocks

  1. Mathematical model of heat transfer to predict distribution of hardness through the Jominy bar; Modelo matematico de la transferencia de calor para predecir el perfil de durezas en probetas Jominy

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, E.; Hernandez, J. B.; Solorio, G.; Vergara, H. J.; Vazquez, O.; Garnica, F.

    2013-06-01

    The heat transfer coefficient was estimated at the bottom surface at Jominy bar end quench specimen by solution of the heat inverse conduction problem. A mathematical model based on the finite-difference method was developed to predict thermal paths and volume fraction of transformed phases. The mathematical model was codified in the commercial package Microsoft Visual Basic v. 6. The calculated thermal path and final phase distribution were used to evaluate the hardness distribution along the AISI 4140 Jominy bar. (Author)

  2. A comparison of radiative transfer models for predicting the microwave emission from soils

    Science.gov (United States)

    Schmugge, T. J.; Choudhury, B. J.

    1981-01-01

    Noncoherent and coherent numerical models for predicting emission from soils are compared. Coherent models use the boundary conditions on the electric fields across the layer boundaries to calculate the radiation intensity, and noncoherent models consider radiation intensities directly. Interference may cause different results in the two approaches when coupling between soil layers in coherent models causes greater soil moisture sampling depths. Calculations performed at frequencies of 1.4 and 19.4 GHz show little difference between the models at 19.4 GHz, although differences are apparent at the lower frequency. A definition for an effective emissivity is also given for when a nonuniform temperature profile is present, and measurements made from a tower show good agreement with calculations from the coherent model.

  3. Radiative Heating in MSL Entry: Comparison of Flight Heating Discrepancy to Ground Test and Predictive Models

    Science.gov (United States)

    Cruden, Brett A.; Brandis, Aaron M.; White, Todd R.; Mahzari, Milad; Bose, Deepak

    2014-01-01

    During the recent entry of the Mars Science Laboratory (MSL), the heat shield was equipped with thermocouple stacks to measure in-depth heating of the thermal protection system (TPS). When only convective heating was considered, the derived heat flux from gauges in the stagnation region was found to be underpredicted by as much as 17 W/sq cm, which is significant compared to the peak heating of 32 W/sq cm. In order to quantify the contribution of radiative heating phenomena to the discrepancy, ground tests and predictive simulations that replicated the MSL entry trajectory were performed. An analysis is carried through to assess the quality of the radiation model and the impact to stagnation line heating. The impact is shown to be significant, but does not fully explain the heating discrepancy.

  4. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  5. Machine Learning Approaches for Predicting Radiation Therapy Outcomes: A Clinician's Perspective.

    Science.gov (United States)

    Kang, John; Schwartz, Russell; Flickinger, John; Beriwal, Sushil

    2015-12-01

    Radiation oncology has always been deeply rooted in modeling, from the early days of isoeffect curves to the contemporary Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) initiative. In recent years, medical modeling for both prognostic and therapeutic purposes has exploded thanks to increasing availability of electronic data and genomics. One promising direction that medical modeling is moving toward is adopting the same machine learning methods used by companies such as Google and Facebook to combat disease. Broadly defined, machine learning is a branch of computer science that deals with making predictions from complex data through statistical models. These methods serve to uncover patterns in data and are actively used in areas such as speech recognition, handwriting recognition, face recognition, "spam" filtering (junk email), and targeted advertising. Although multiple radiation oncology research groups have shown the value of applied machine learning (ML), clinical adoption has been slow due to the high barrier to understanding these complex models by clinicians. Here, we present a review of the use of ML to predict radiation therapy outcomes from the clinician's point of view with the hope that it lowers the "barrier to entry" for those without formal training in ML. We begin by describing 7 principles that one should consider when evaluating (or creating) an ML model in radiation oncology. We next introduce 3 popular ML methods--logistic regression (LR), support vector machine (SVM), and artificial neural network (ANN)--and critique 3 seminal papers in the context of these principles. Although current studies are in exploratory stages, the overall methodology has progressively matured, and the field is ready for larger-scale further investigation. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Machine Learning Approaches for Predicting Radiation Therapy Outcomes: A Clinician's Perspective

    International Nuclear Information System (INIS)

    Kang, John; Schwartz, Russell; Flickinger, John; Beriwal, Sushil

    2015-01-01

    Radiation oncology has always been deeply rooted in modeling, from the early days of isoeffect curves to the contemporary Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) initiative. In recent years, medical modeling for both prognostic and therapeutic purposes has exploded thanks to increasing availability of electronic data and genomics. One promising direction that medical modeling is moving toward is adopting the same machine learning methods used by companies such as Google and Facebook to combat disease. Broadly defined, machine learning is a branch of computer science that deals with making predictions from complex data through statistical models. These methods serve to uncover patterns in data and are actively used in areas such as speech recognition, handwriting recognition, face recognition, “spam” filtering (junk email), and targeted advertising. Although multiple radiation oncology research groups have shown the value of applied machine learning (ML), clinical adoption has been slow due to the high barrier to understanding these complex models by clinicians. Here, we present a review of the use of ML to predict radiation therapy outcomes from the clinician's point of view with the hope that it lowers the “barrier to entry” for those without formal training in ML. We begin by describing 7 principles that one should consider when evaluating (or creating) an ML model in radiation oncology. We next introduce 3 popular ML methods—logistic regression (LR), support vector machine (SVM), and artificial neural network (ANN)—and critique 3 seminal papers in the context of these principles. Although current studies are in exploratory stages, the overall methodology has progressively matured, and the field is ready for larger-scale further investigation.

  7. Machine Learning Approaches for Predicting Radiation Therapy Outcomes: A Clinician's Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kang, John [Medical Scientist Training Program, University of Pittsburgh-Carnegie Mellon University, Pittsburgh, Pennsylvania (United States); Schwartz, Russell [Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania (United States); Flickinger, John [Departments of Radiation Oncology and Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (United States); Beriwal, Sushil, E-mail: beriwals@upmc.edu [Department of Radiation Oncology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (United States)

    2015-12-01

    Radiation oncology has always been deeply rooted in modeling, from the early days of isoeffect curves to the contemporary Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) initiative. In recent years, medical modeling for both prognostic and therapeutic purposes has exploded thanks to increasing availability of electronic data and genomics. One promising direction that medical modeling is moving toward is adopting the same machine learning methods used by companies such as Google and Facebook to combat disease. Broadly defined, machine learning is a branch of computer science that deals with making predictions from complex data through statistical models. These methods serve to uncover patterns in data and are actively used in areas such as speech recognition, handwriting recognition, face recognition, “spam” filtering (junk email), and targeted advertising. Although multiple radiation oncology research groups have shown the value of applied machine learning (ML), clinical adoption has been slow due to the high barrier to understanding these complex models by clinicians. Here, we present a review of the use of ML to predict radiation therapy outcomes from the clinician's point of view with the hope that it lowers the “barrier to entry” for those without formal training in ML. We begin by describing 7 principles that one should consider when evaluating (or creating) an ML model in radiation oncology. We next introduce 3 popular ML methods—logistic regression (LR), support vector machine (SVM), and artificial neural network (ANN)—and critique 3 seminal papers in the context of these principles. Although current studies are in exploratory stages, the overall methodology has progressively matured, and the field is ready for larger-scale further investigation.

  8. Combining multiple models to generate consensus: Application to radiation-induced pneumonitis prediction

    Energy Technology Data Exchange (ETDEWEB)

    Das, Shiva K.; Chen Shifeng; Deasy, Joseph O.; Zhou Sumin; Yin Fangfang; Marks, Lawrence B. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599 (United States)

    2008-11-15

    The fusion of predictions from disparate models has been used in several fields to obtain a more realistic and robust estimate of the ''ground truth'' by allowing the models to reinforce each other when consensus exists, or, conversely, negate each other when there is no consensus. Fusion has been shown to be most effective when the models have some complementary strengths arising from different approaches. In this work, we fuse the results from four common but methodologically different nonlinear multivariate models (Decision Trees, Neural Networks, Support Vector Machines, Self-Organizing Maps) that were trained to predict radiation-induced pneumonitis risk on a database of 219 lung cancer patients treated with radiotherapy (34 with Grade 2+ postradiotherapy pneumonitis). Each model independently incorporated a small number of features from the available set of dose and nondose patient variables to predict pneumonitis; no two models had all features in common. Fusion was achieved by simple averaging of the predictions for each patient from all four models. Since a model's prediction for a patient can be dependent on the patient training set used to build the model, the average of several different predictions from each model was used in the fusion (predictions were made by repeatedly testing each patient with a model built from different cross-validation training sets that excluded the patient being tested). The area under the receiver operating characteristics curve for the fused cross-validated results was 0.79, with lower variance than the individual component models. From the fusion, five features were extracted as the consensus among all four models in predicting radiation pneumonitis. Arranged in order of importance, the features are (1) chemotherapy; (2) equivalent uniform dose (EUD) for exponent a=1.2 to 3; (3) EUD for a=0.5 to 1.2, lung volume receiving >20-30 Gy; (4) female sex; and (5) squamous cell histology. To facilitate

  9. Population sensitivities of animals to chronic ionizing radiation-model predictions from mice to elephant.

    Science.gov (United States)

    Sazykina, Tatiana G

    2018-02-01

    Model predictions of population response to chronic ionizing radiation (endpoint 'morbidity') were made for 11 species of warm-blooded animals, differing in body mass and lifespan - from mice to elephant. Predictions were made also for 3 bird species (duck, pigeon, and house sparrow). Calculations were based on analytical solutions of the mathematical model, simulating a population response to low-LET ionizing radiation in an ecosystem with a limiting resource (Sazykina, Kryshev, 2016). Model parameters for different species were taken from biological and radioecological databases; allometric relationships were employed for estimating some parameter values. As a threshold of decreased health status in exposed populations ('health threshold'), a 10% reduction in self-repairing capacity of organisms was suggested, associated with a decline in ability to sustain environmental stresses. Results of the modeling demonstrate a general increase of population vulnerability to ionizing radiation in animal species of larger size and longevity. Populations of small widespread species (mice, house sparrow; body mass 20-50 g), which are characterized by intensive metabolism and short lifespan, have calculated 'health thresholds' at dose rates about 6.5-7.5 mGy day -1 . Widespread animals with body mass 200-500 g (rat, common pigeon) - demonstrate 'health threshold' values at 4-5 mGy day -1 . For populations of animals with body mass 2-5 kg (rabbit, fox, raccoon), the indicators of 10% health decrease are in the range 2-3.4 mGy day -1 . For animals with body mass 40-100 kg (wolf, sheep, wild boar), thresholds are within 0.5-0.8 mGy day -1 ; for herbivorous animals with body mass 200-300 kg (deer, horse) - 0.5-0.6 mGy day -1 . The lowest health threshold was estimated for elephant (body mass around 5000 kg) - 0.1 mGy day -1 . According to the model results, the differences in population sensitivities of warm-blooded animal species to ionizing radiation are generally

  10. Formulating the strength factor α for improved predictability of radiation hardening

    Energy Technology Data Exchange (ETDEWEB)

    Tan, L., E-mail: tanl@ornl.gov; Busby, J.T.

    2015-10-15

    Analytical equations were developed to calculate the strength factors of precipitates, Frank loops, and cavities in austenitic alloys, which strongly depend on barrier type, size, geometry and density, as well as temperature. Calculated strength factors were successfully used to estimate radiation hardening using the broadly employed dispersed barrier-hardening model, leading to good agreement with experimentally measured hardening in neutron-irradiated type 304 and 316 stainless steel variants. The formulated strength factor provides a route for more reliable hardening predictions and can be easily incorporated into component simulations and design.

  11. A new approach to reduce uncertainties in space radiation cancer risk predictions.

    Directory of Open Access Journals (Sweden)

    Francis A Cucinotta

    Full Text Available The prediction of space radiation induced cancer risk carries large uncertainties with two of the largest uncertainties being radiation quality and dose-rate effects. In risk models the ratio of the quality factor (QF to the dose and dose-rate reduction effectiveness factor (DDREF parameter is used to scale organ doses for cosmic ray proton and high charge and energy (HZE particles to a hazard rate for γ-rays derived from human epidemiology data. In previous work, particle track structure concepts were used to formulate a space radiation QF function that is dependent on particle charge number Z, and kinetic energy per atomic mass unit, E. QF uncertainties where represented by subjective probability distribution functions (PDF for the three QF parameters that described its maximum value and shape parameters for Z and E dependences. Here I report on an analysis of a maximum QF parameter and its uncertainty using mouse tumor induction data. Because experimental data for risks at low doses of γ-rays are highly uncertain which impacts estimates of maximum values of relative biological effectiveness (RBEmax, I developed an alternate QF model, denoted QFγAcute where QFs are defined relative to higher acute γ-ray doses (0.5 to 3 Gy. The alternate model reduces the dependence of risk projections on the DDREF, however a DDREF is still needed for risk estimates for high-energy protons and other primary or secondary sparsely ionizing space radiation components. Risk projections (upper confidence levels (CL for space missions show a reduction of about 40% (CL∼50% using the QFγAcute model compared the QFs based on RBEmax and about 25% (CL∼35% compared to previous estimates. In addition, I discuss how a possible qualitative difference leading to increased tumor lethality for HZE particles compared to low LET radiation and background tumors remains a large uncertainty in risk estimates.

  12. Improving the Accuracy of a Heliocentric Potential (HCP Prediction Model for the Aviation Radiation Dose

    Directory of Open Access Journals (Sweden)

    Junga Hwang

    2016-12-01

    Full Text Available The space radiation dose over air routes including polar routes should be carefully considered, especially when space weather shows sudden disturbances such as coronal mass ejections (CMEs, flares, and accompanying solar energetic particle events. We recently established a heliocentric potential (HCP prediction model for real-time operation of the CARI-6 and CARI-6M programs. Specifically, the HCP value is used as a critical input value in the CARI-6/6M programs, which estimate the aviation route dose based on the effective dose rate. The CARI-6/6M approach is the most widely used technique, and the programs can be obtained from the U.S. Federal Aviation Administration (FAA. However, HCP values are given at a one month delay on the FAA official webpage, which makes it difficult to obtain real-time information on the aviation route dose. In order to overcome this critical limitation regarding the time delay for space weather customers, we developed a HCP prediction model based on sunspot number variations (Hwang et al. 2015. In this paper, we focus on improvements to our HCP prediction model and update it with neutron monitoring data. We found that the most accurate method to derive the HCP value involves (1 real-time daily sunspot assessments, (2 predictions of the daily HCP by our prediction algorithm, and (3 calculations of the resultant daily effective dose rate. Additionally, we also derived the HCP prediction algorithm in this paper by using ground neutron counts. With the compensation stemming from the use of ground neutron count data, the newly developed HCP prediction model was improved.

  13. 20. Prediction of 10-year risk of hard coronary events among Saudi adults based on prevalence of heart disease risk factors

    Directory of Open Access Journals (Sweden)

    Muhammad Adil Soofi

    2015-10-01

    Conclusions: Our study is the first to estimate the 10-year risk of HCE among adults in an emerging country and discovered a significant proportion of younger aged population are at risk for development of hard coronary events. Public awareness programs to control risk factors are warranted.

  14. A flavor dependent gauge symmetry, predictive radiative seesaw and LHCb anomalies

    Directory of Open Access Journals (Sweden)

    P. Ko

    2017-09-01

    Full Text Available We propose a predictive radiative seesaw model at one-loop level with a flavor dependent gauge symmetry U(1xB3−xe−μ+τ and Majorana fermion dark matter. For the neutrino mass matrix, we obtain an A1 type texture (with two zeros that provides us several predictions such as the normal ordering for the neutrino masses. We analyze the constraints from lepton flavor violations, relic density of dark matter, and collider physics for the new U(1xB3−xe−μ+τ gauge boson. Within the allowed region, the LHCb anomalies in B→K⁎μ+μ− and B→Kℓ+ℓ− with ℓ=e or μ can be resolved, and such Z′ could be also observed at the LHC.

  15. Modelling techniques for predicting the long term consequences of radiation on natural aquatic populations

    International Nuclear Information System (INIS)

    Wallis, I.G.

    1978-01-01

    The purpose of this working paper is to describe modelling techniques for predicting the long term consequences of radiation on natural aquatic populations. Ideally, it would be possible to use aquatic population models: (1) to predict changes in the health and well-being of all aquatic populations as a result of changing the composition, amount and location of radionuclide discharges; (2) to compare the effects of steady, fluctuating and accidental releases of radionuclides; and (3) to evaluate the combined impact of the discharge of radionuclides and other wastes, and natural environmental stresses on aquatic populations. At the onset it should be stated that there is no existing model which can achieve this ideal performance. However, modelling skills and techniques are available to develop useful aquatic population models. This paper discusses the considerations involved in developing these models and briefly describes the various types of population models which have been developed to date

  16. New paradigm for prediction of radiation life-time of reactor pressure vessel

    International Nuclear Information System (INIS)

    Kotrechko, S.A.; Meshkov, Yu.Ya.; Neklyudov, I.M.; Revka, V.N.

    2011-01-01

    New paradigm for prediction of radiation life-time of reactor pressure vessel is presented. Equation for limiting state of reactor pressure vessel wall with crack-like defect is obtained. It is exhibited that the value of critical fluence Φ c may be determined not by shift of critical temperature of fracture of surveillance specimen, which is indirect characteristic, but by direct method, namely, by the condition of initiation of brittle fracture of irradiated metal ahead of a crack in RPV wall. Within the framework of engineering version of LA to fracture the technique for Φ c ascertainment is developed. Prediction of Φ c for WWER pressure vessels demonstrates potentialities of this technique.

  17. Rad Hard Active Media For Calorimeters

    CERN Document Server

    Norbeck, E; Möller, A; Onel, Y

    2006-01-01

    Zero-degree calorimeters have limited space and extreme levels of radiation. A simple, low cost, radiation hard design uses tungstenmetal as the absorber and a suitable liquid as the ˇCerenkov radiator. In other applications a PPAC (Parallel Plate Avalanche Counter) operatingwith a suitable atmosphericpressure gas is an attractive active material for a calorimeter. It can be made radiation hard and has sufficient gain in the gas that no electronic components are needed near the detector. It works well even with the highest concentration of shower particles. For this pressure range, R134A (used in auto air conditioners) has many desirable features.

  18. Radiation

    International Nuclear Information System (INIS)

    2013-01-01

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  19. Random Forests to Predict Rectal Toxicity Following Prostate Cancer Radiation Therapy

    International Nuclear Information System (INIS)

    Ospina, Juan D.; Zhu, Jian; Chira, Ciprian; Bossi, Alberto; Delobel, Jean B.; Beckendorf, Véronique; Dubray, Bernard; Lagrange, Jean-Léon; Correa, Juan C.

    2014-01-01

    Purpose: To propose a random forest normal tissue complication probability (RF-NTCP) model to predict late rectal toxicity following prostate cancer radiation therapy, and to compare its performance to that of classic NTCP models. Methods and Materials: Clinical data and dose-volume histograms (DVH) were collected from 261 patients who received 3-dimensional conformal radiation therapy for prostate cancer with at least 5 years of follow-up. The series was split 1000 times into training and validation cohorts. A RF was trained to predict the risk of 5-year overall rectal toxicity and bleeding. Parameters of the Lyman-Kutcher-Burman (LKB) model were identified and a logistic regression model was fit. The performance of all the models was assessed by computing the area under the receiving operating characteristic curve (AUC). Results: The 5-year grade ≥2 overall rectal toxicity and grade ≥1 and grade ≥2 rectal bleeding rates were 16%, 25%, and 10%, respectively. Predictive capabilities were obtained using the RF-NTCP model for all 3 toxicity endpoints, including both the training and validation cohorts. The age and use of anticoagulants were found to be predictors of rectal bleeding. The AUC for RF-NTCP ranged from 0.66 to 0.76, depending on the toxicity endpoint. The AUC values for the LKB-NTCP were statistically significantly inferior, ranging from 0.62 to 0.69. Conclusions: The RF-NTCP model may be a useful new tool in predicting late rectal toxicity, including variables other than DVH, and thus appears as a strong competitor to classic NTCP models

  20. Prospective assessment of dosimetric/physiologic-based models for predicting radiation pneumonitis

    International Nuclear Information System (INIS)

    Kocak, Zafer; Borst, Gerben R.; Zeng Jing; Zhou Sumin; Hollis, Donna R.; Zhang Junan; Evans, Elizabeth S.; Folz, Rodney J.; Wong, Terrence; Kahn, Daniel; Belderbos, Jose S.A.; Lebesque, Joos V.; Marks, Lawrence B.

    2007-01-01

    Purpose: Clinical and 3D dosimetric parameters are associated with symptomatic radiation pneumonitis rates in retrospective studies. Such parameters include: mean lung dose (MLD), radiation (RT) dose to perfused lung (via SPECT), and pre-RT lung function. Based on prior publications, we defined pre-RT criteria hypothesized to be predictive for later development of pneumonitis. We herein prospectively test the predictive abilities of these dosimetric/functional parameters on 2 cohorts of patients from Duke and Netherlands Cancer Institute (NKI). Methods and Materials: For the Duke cohort, 55 eligible patients treated between 1999 and 2005 on a prospective IRB-approved study to monitor RT-induced lung injury were analyzed. A similar group of patients treated at the NKI between 1996 and 2002 were identified. Patients believed to be at high and low risk for pneumonitis were defined based on: (1) MLD; (2) OpRP (sum of predicted perfusion reduction based on regional dose-response curve); and (3) pre-RT DLCO. All doses reflected tissue density heterogeneity. The rates of grade ≥2 pneumonitis in the 'presumed' high and low risk groups were compared using Fisher's exact test. Results: In the Duke group, pneumonitis rates in patients prospectively deemed to be at 'high' vs. 'low' risk are 7 of 20 and 9 of 35, respectively; p = 0.33 one-tailed Fisher's. Similarly, comparable rates for the NKI group are 4 of 21 and 6 of 44, respectively, p = 0.41 one-tailed Fisher's. Conclusion: The prospective model appears unable to accurately segregate patients into high vs. low risk groups. However, considered retrospectively, these data are consistent with prior studies suggesting that dosimetric (e.g., MLD) and functional (e.g., PFTs or SPECT) parameters are predictive for RT-induced pneumonitis. Additional work is needed to better identify, and prospectively assess, predictors of RT-induced lung injury

  1. In vitro assays for predicting tumor cell response to radiation by apoptotic pathways

    International Nuclear Information System (INIS)

    Algan, Oe.; Hanks, G.E.; Biade, S.; Chapman, J.D.

    1995-01-01

    Purpose: We had previously shown that the rate of spontaneous and radiation-induced apoptosis was significantly greater in well-differentiated compared to anaplastic Dunning prostate carcinomas. The goal of this study was to define the most useful assay for quantifying radiation-induced apoptotic cell death and to determine if measured rates of radiation-induced apoptosis in tumor cell populations can predict treatment outcome. Materials and Methods: The time course and extent of radiation-induced apoptosis after single doses of Cesium-137 gamma-rays were measured by five different assays. These included gross DNA degradation, nucleosome ladder formation, labeling of 3'-OH ends in DNA with an immunofluorescence probe, immunofluorescence vital stains (LIVE/DEAD[reg] EUKOLIGHT TM ) and trypan blue. The majority of these studies were performed with DU-145 human prostate cells. Data was analyzed to determine the component of cell inactivation resulting from apoptosis with the modified linear quadratic equation, -1n (SF) = (α a + α p ) D + β p D 2 , were α a represents cell inactivation by radiation-induced apoptosis, α p and β p represent cell death by proliferative mechanisms and D represents radiation dose. Results: These studies indicated that DU-145 cell death after radiation occurs over two distinct time periods. The first phase of death begins shortly after irradiation and plateaus within 16-24 hr. This process of cell death has properties consistent with apoptosis as determined by 3'-OH DNA end-labeling and nucleosome ladder assays. The second phase of cell death (determined by viability staining) begins approximately 48 hr after irradiation and continues until the remainder of inactivated cells express their death. This longer phase of cell inactivation probably represents proliferative cell death and other non-apoptotic mechanisms. The five different assays were performed on DU-145 cells 24 hr after irradiation with 10 Gy. Significant nucleosome ladders

  2. Determining if pretreatment PSA doubling time predicts PSA trajectories after radiation therapy for localized prostate cancer

    International Nuclear Information System (INIS)

    Soto, Daniel E.; Andridge, Rebecca R.; Pan, Charlie C.; Williams, Scott G.; Taylor, Jeremy M.G.; Sandler, Howard M.

    2009-01-01

    Introduction: To determine if pretreatment PSA doubling time (PSA-DT) can predict post-radiation therapy (RT) PSA trajectories for localized prostate cancer. Materials and methods: Three hundred and seventy-five prostate cancer patients treated with external beam RT without androgen deprivation therapy (ADT) were identified with an adequate number of PSA values. We utilized a linear mixed model (LMM) analysis to model longitudinal PSA data sets after definitive treatment. Post-treatment PSA trajectories were allowed to depend on the pre-RT PSA-DT, pre-RT PSA (iPSA), Gleason score (GS), and T-stage. Results: Pre-RT PSA-DT had a borderline impact on predicting the rate of PSA rise after nadir (p = 0.08). For a typical low risk patient (T1, GS ≤ 6, iPSA 10), the predicted PSA-DT post-nadir was 21% shorter for pre-RT PSA-DT 24 month (19 month vs. 24 month). Additional significant predictors of post-RT PSA rate of rise included GS (p < 0.0001), iPSA (p < 0.0001), and T-stage (p = 0.02). Conclusions: We observed a trend between rapidly rising pre-RT PSA and the post-RT post-nadir PSA rise. This effect appeared to be independent of iPSA, GS, or T-stage. The results presented suggest that pretreatment PSA-DT may help predict post-RT PSA trajectories

  3. Microsatellite Instability Predicts Clinical Outcome in Radiation-Treated Endometrioid Endometrial Cancer

    International Nuclear Information System (INIS)

    Bilbao, Cristina; Lara, Pedro Carlos; Ramirez, Raquel; Henriquez-Hernandez, Luis Alberto; Rodriguez, German; Falcon, Orlando; Leon, Laureano; Perucho, Manuel

    2010-01-01

    Purpose: To elucidate whether microsatellite instability (MSI) predicts clinical outcome in radiation-treated endometrioid endometrial cancer (EEC). Methods and Materials: A consecutive series of 93 patients with EEC treated with extrafascial hysterectomy and postoperative radiotherapy was studied. The median clinical follow-up of patients was 138 months, with a maximum of 232 months. Five quasimonomorphic mononucleotide markers (BAT-25, BAT-26, NR21, NR24, and NR27) were used for MSI classification. Results: Twenty-five patients (22%) were classified as MSI. Both in the whole series and in early stages (I and II), univariate analysis showed a significant association between MSI and poorer 10-year local disease-free survival, disease-free survival, and cancer-specific survival. In multivariate analysis, MSI was excluded from the final regression model in the whole series, but in early stages MSI provided additional significant predictive information independent of traditional prognostic and predictive factors (age, stage, grade, and vascular invasion) for disease-free survival (hazard ratio [HR] 3.25, 95% confidence interval [CI] 1.01-10.49; p = 0.048) and cancer-specific survival (HR 4.20, 95% CI 1.23-14.35; p = 0.022) and was marginally significant for local disease-free survival (HR 3.54, 95% CI 0.93-13.46; p = 0.064). Conclusions: These results suggest that MSI may predict radiotherapy response in early-stage EEC.

  4. Theory and validation of a liquid radiation filter greenhouse simulation for performance prediction

    International Nuclear Information System (INIS)

    Feuermann, D.; Kopel, R.; Zeroni, M.; Levi, S.; Gale, J.

    1997-01-01

    A greenhouse is described which has a selectively absorbing liquid radiation filter (LRF) circulating in double layered cladding. The filter removes much of the near infrared wave band of solar radiation (700 nm) while transmitting most of the photosynthetic radiation (400-700 nm). This greatly reduces the heat input to the greenhouse and, by transferring heat from day to night, facilitates better temperature control. This is particularly important for CO2 fertilization, which requires that the greenhouse should remain closed during daylight hours. A computer simulation model was developed to study the relationship between design parameters of such a LRF greenhouse and its thermal performance under different climatic conditions. The model was based on a small number of governing equations describing the major physical phenomena responsible for the greenhouse climate. Validation of the simulation was performed with data from a 330 m2 LRF greenhouse, operating in the Negev (Israel) desert highlands. The predicted greenhouse temperatures were found to agree with measured values to within one to two degrees Celsius. Performances of a LRF and a conventional greenhouse were compared using the simulation and hourly meteorological data for central Israel. For the summer season of May to October, the number of daylight hours during which the LRF greenhouse could remain closed was larger by about two-thirds than that of the conventional greenhouse

  5. Monitoring Top-of-Atmosphere Radiative Energy Imbalance for Climate Prediction

    Science.gov (United States)

    Lin, Bing; Chambers, Lin H.; Stackhouse, Paul W., Jr.; Minnis, Patrick

    2009-01-01

    Large climate feedback uncertainties limit the prediction accuracy of the Earth s future climate with an increased CO2 atmosphere. One potential to reduce the feedback uncertainties using satellite observations of top-of-atmosphere (TOA) radiative energy imbalance is explored. Instead of solving the initial condition problem in previous energy balance analysis, current study focuses on the boundary condition problem with further considerations on climate system memory and deep ocean heat transport, which is more applicable for the climate. Along with surface temperature measurements of the present climate, the climate feedbacks are obtained based on the constraints of the TOA radiation imbalance. Comparing to the feedback factor of 3.3 W/sq m/K of the neutral climate system, the estimated feedback factor for the current climate system ranges from -1.3 to -1.0 W/sq m/K with an uncertainty of +/-0.26 W/sq m/K. That is, a positive climate feedback is found because of the measured TOA net radiative heating (0.85 W/sq m) to the climate system. The uncertainty is caused by the uncertainties in the climate memory length. The estimated time constant of the climate is large (70 to approx. 120 years), implying that the climate is not in an equilibrium state under the increasing CO2 forcing in the last century.

  6. Modeling radiation dosimetry to predict cognitive outcomes in pediatric patients with CNS embryonal tumors including medulloblastoma

    International Nuclear Information System (INIS)

    Merchant, Thomas E.; Kiehna, Erin N.; Li Chenghong; Shukla, Hemant; Sengupta, Saikat; Xiong Xiaoping; Gajjar, Amar; Mulhern, Raymond K.

    2006-01-01

    Purpose: Model the effects of radiation dosimetry on IQ among pediatric patients with central nervous system (CNS) tumors. Methods and Materials: Pediatric patients with CNS embryonal tumors (n = 39) were prospectively evaluated with serial cognitive testing, before and after treatment with postoperative, risk-adapted craniospinal irradiation (CSI) and conformal primary-site irradiation, followed by chemotherapy. Differential dose-volume data for 5 brain volumes (total brain, supratentorial brain, infratentorial brain, and left and right temporal lobes) were correlated with IQ after surgery and at follow-up by use of linear regression. Results: When the dose distribution was partitioned into 2 levels, both had a significantly negative effect on longitudinal IQ across all 5 brain volumes. When the dose distribution was partitioned into 3 levels (low, medium, and high), exposure to the supratentorial brain appeared to have the most significant impact. For most models, each Gy of exposure had a similar effect on IQ decline, regardless of dose level. Conclusions: Our results suggest that radiation dosimetry data from 5 brain volumes can be used to predict decline in longitudinal IQ. Despite measures to reduce radiation dose and treatment volume, the volume that receives the highest dose continues to have the greatest effect, which supports current volume-reduction efforts

  7. Radiation-induced brain structural and functional abnormalities in presymptomatic phase and outcome prediction.

    Science.gov (United States)

    Ding, Zhongxiang; Zhang, Han; Lv, Xiao-Fei; Xie, Fei; Liu, Lizhi; Qiu, Shijun; Li, Li; Shen, Dinggang

    2018-01-01

    Radiation therapy, a major method of treatment for brain cancer, may cause severe brain injuries after many years. We used a rare and unique cohort of nasopharyngeal carcinoma patients with normal-appearing brains to study possible early irradiation injury in its presymptomatic phase before severe, irreversible necrosis happens. The aim is to detect any structural or functional imaging biomarker that is sensitive to early irradiation injury, and to understand the recovery and progression of irradiation injury that can shed light on outcome prediction for early clinical intervention. We found an acute increase in local brain activity that is followed by extensive reductions in such activity in the temporal lobe and significant loss of functional connectivity in a distributed, large-scale, high-level cognitive function-related brain network. Intriguingly, these radiosensitive functional alterations were found to be fully or partially recoverable. In contrast, progressive late disruptions to the integrity of the related far-end white matter structure began to be significant after one year. Importantly, early increased local brain functional activity was predictive of severe later temporal lobe necrosis. Based on these findings, we proposed a dynamic, multifactorial model for radiation injury and another preventive model for timely clinical intervention. Hum Brain Mapp 39:407-427, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. Evaluation and prediction of solar radiation for energy management based on neural networks

    Science.gov (United States)

    Aldoshina, O. V.; Van Tai, Dinh

    2017-08-01

    Currently, there is a high rate of distribution of renewable energy sources and distributed power generation based on intelligent networks; therefore, meteorological forecasts are particularly useful for planning and managing the energy system in order to increase its overall efficiency and productivity. The application of artificial neural networks (ANN) in the field of photovoltaic energy is presented in this article. Implemented in this study, two periodically repeating dynamic ANS, that are the concentration of the time delay of a neural network (CTDNN) and the non-linear autoregression of a network with exogenous inputs of the NAEI, are used in the development of a model for estimating and daily forecasting of solar radiation. ANN show good productivity, as reliable and accurate models of daily solar radiation are obtained. This allows to successfully predict the photovoltaic output power for this installation. The potential of the proposed method for controlling the energy of the electrical network is shown using the example of the application of the NAEI network for predicting the electric load.

  9. Standard practice for application of thermoluminescence-dosimetry (TLD) systems for determining absorbed dose in radiation-hardness testing of electronic devices. ASTM standard

    International Nuclear Information System (INIS)

    1998-05-01

    This practice is under the jurisdiction of ASTM Committee E-10 on Nuclear Technology and Applications and is the direct responsibility of Subcommittee E10.07 on Radiation Dosimetry for Radiation Effects on Materials and Devices. Current edition approved Jun. 10, 1997. Published May 1998. Originally published as E 668-78. Last previous edition E 668-93

  10. Addressing Common Cloud-Radiation Errors from 4-hour to 4-week Model Prediction

    Science.gov (United States)

    Benjamin, S.; Sun, S.; Grell, G. A.; Green, B.; Olson, J.; Kenyon, J.; James, E.; Smirnova, T. G.; Brown, J. M.

    2017-12-01

    Cloud-radiation representation in models for subgrid-scale clouds is a known gap from subseasonal-to-seasonal models down to storm-scale models applied for forecast duration of only a few hours. NOAA/ESRL has been applying common physical parameterizations for scale-aware deep/shallow convection and boundary-layer mixing over this wide range of time and spatial scales, with some progress to be reported in this presentation. The Grell-Freitas scheme (2014, Atmos. Chem. Phys.) and MYNN boundary-layer EDMF scheme (Olson / Benjamin et al. 2016 Mon. Wea. Rev.) have been applied and tested extensively for the NOAA hourly updated 3-km High-Resolution Rapid Refresh (HRRR) and 13-km Rapid Refresh (RAP) model/assimilation systems over the United States and North America, with targeting toward improvement to boundary-layer evolution and cloud-radiation representation in all seasons. This representation is critical for both warm-season severe convective storm forecasting and for winter-storm prediction of snow and mixed precipitation. At the same time the Grell-Freitas scheme has been applied also as an option for subseasonal forecasting toward improved US week 3-4 prediction with the FIM-HYCOM coupled model (Green et al 2017, MWR). Cloud/radiation evaluation using CERES satellite-based estimates have been applied to both 12-h RAP (13km) and also during Weeks 1-4 from 32-day FIM-HYCOM (60km) forecasts. Initial results reveal that improved cloud representation is needed for both resolutions and now is guiding further refinement for cloud representation including with the Grell-Freitas scheme and with the updated MYNN-EDMF scheme (both now also in global testing as well as with the 3km HRRR and 13km RAP models).

  11. A Mixed Analog-Digital Radiation Hard Technology for High Energy Physics Electronics: DMILL~(Durci~Mixte~sur~Isolant~Logico-Lineaire)

    CERN Multimedia

    Lugiez, F; Leray, J; Rouger, M; Fourches, N T; Musseau, O; Potheau, R

    2002-01-01

    %RD29 %title\\\\ \\\\Physics experiments under preparation with the future LHC require a fast, low noise, very rad-hard (>10 Mrad and >10$^{14}$ neutron/cm$^{2}$), mixed analog-digital microelectronics VLSI technology.\\\\ \\\\The DMILL microelectronics technology (RD29) was developed between 1990 and 1995 by a Consortium gathering the CEA and the firm Thomson-TCS, with the collaboration of IN2P3. The goal of the DMILL program, which is now completed, was to provide the High Energy Physics community, space industry, nuclear industry, and other applications, with an industrial very rad-hard mixed analog-digital microelectronics technology.\\\\ \\\\DMILL integrates mixed analog-digital very rad-hard (>10 Mrad and >10$^{14}$ neutron/cm$^{2}$) vertical bipolar, 0.8 $\\mu$m CMOS and 1.2 $\\mu$m PJFET transistors. Its SOI substrate and its dielectric trenches strongly reduce SEU sensitivity and completely eliminate any possibility of latch-up. Its four transistors are optimized to obtain low-noise features. DMILL also integrates...

  12. The prediction of human exposure to substances and radiation. The status of RIVM research

    International Nuclear Information System (INIS)

    Vermeire, T.; Veeren, M. van; Janssen, M.

    1998-03-01

    In 1994, the substances and risks sector of the National Institute of Public Health and the Environment (RIVM) decided to strengthen its research into risk assessment methodology strategically. To further this goal, this report describes the area of RIVM research dealing with the prediction of human exposure. A representative selection of the models used to predict human exposure to both chemical substances and radiation is analysed. The analysis considers aspects of the models such as the aims, basic principles, the extent to which the models have been analysed and values of default parameters. For comparison purposes, a model used to assess human exposure to micro-organisms is also included. All models are being, or are about to be, used operationally to produce risk assessments in the substances and risks sector and also in the public health and environmental research sectors. All the models discussed have a defined area of application and are directly available in support of policy implementation. Comparison of areas of research dealing with exposure assessment for substances and radiation reveals many methodological similarities. However, at the level of models and parameters, an in-depth analysis of these similarities and explained or unexplained differences is lacking. A first attempt is made in this report. Detailed examination of organisational aspects and RIVM-models for human exposure prediction reveals that all relevant areas of interest are covered. The range of methodology for the prediction of actual risks and exposures is great, for all exposure routes. The coverage is more uniform for radiation than for chemical substances, however. For both areas the prediction and recording of emissions could be improved. The development of risk assessment systems and related harmonisation projects have been underway for many years (for example CSOIL, USES, RIBRON). The methodology for the prediction of actual exposures and risks still requires further

  13. Levels of naturally occurring gamma radiation measured in British homes and their prediction in particular residences

    Energy Technology Data Exchange (ETDEWEB)

    Kendall, G.M. [University of Oxford, Cancer Epidemiology Unit, Oxford (United Kingdom); Wakeford, R. [University of Manchester, Centre for Occupational and Environmental Health, Institute of Population Health, Manchester (United Kingdom); Athanson, M. [University of Oxford, Bodleian Library, Oxford (United Kingdom); Vincent, T.J. [University of Oxford, Childhood Cancer Research Group, Oxford (United Kingdom); Carter, E.J. [University of Worcester, Earth Heritage Trust, Geological Records Centre, Henwick Grove, Worcester (United Kingdom); McColl, N.P. [Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxon (United Kingdom); Little, M.P. [National Cancer Institute, DHHS, NIH, Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, Bethesda, MD (United States)

    2016-03-15

    Gamma radiation from natural sources (including directly ionising cosmic rays) is an important component of background radiation. In the present paper, indoor measurements of naturally occurring gamma rays that were undertaken as part of the UK Childhood Cancer Study are summarised, and it is shown that these are broadly compatible with an earlier UK National Survey. The distribution of indoor gamma-ray dose rates in Great Britain is approximately normal with mean 96 nGy/h and standard deviation 23 nGy/h. Directly ionising cosmic rays contribute about one-third of the total. The expanded dataset allows a more detailed description than previously of indoor gamma-ray exposures and in particular their geographical variation. Various strategies for predicting indoor natural background gamma-ray dose rates were explored. In the first of these, a geostatistical model was fitted, which assumes an underlying geologically determined spatial variation, superimposed on which is a Gaussian stochastic process with Matern correlation structure that models the observed tendency of dose rates in neighbouring houses to correlate. In the second approach, a number of dose-rate interpolation measures were first derived, based on averages over geologically or administratively defined areas or using distance-weighted averages of measurements at nearest-neighbour points. Linear regression was then used to derive an optimal linear combination of these interpolation measures. The predictive performances of the two models were compared via cross-validation, using a randomly selected 70 % of the data to fit the models and the remaining 30 % to test them. The mean square error (MSE) of the linear-regression model was lower than that of the Gaussian-Matern model (MSE 378 and 411, respectively). The predictive performance of the two candidate models was also evaluated via simulation; the OLS model performs significantly better than the Gaussian-Matern model. (orig.)

  14. Levels of naturally occurring gamma radiation measured in British homes and their prediction in particular residences

    International Nuclear Information System (INIS)

    Kendall, G.M.; Wakeford, R.; Athanson, M.; Vincent, T.J.; Carter, E.J.; McColl, N.P.; Little, M.P.

    2016-01-01

    Gamma radiation from natural sources (including directly ionising cosmic rays) is an important component of background radiation. In the present paper, indoor measurements of naturally occurring gamma rays that were undertaken as part of the UK Childhood Cancer Study are summarised, and it is shown that these are broadly compatible with an earlier UK National Survey. The distribution of indoor gamma-ray dose rates in Great Britain is approximately normal with mean 96 nGy/h and standard deviation 23 nGy/h. Directly ionising cosmic rays contribute about one-third of the total. The expanded dataset allows a more detailed description than previously of indoor gamma-ray exposures and in particular their geographical variation. Various strategies for predicting indoor natural background gamma-ray dose rates were explored. In the first of these, a geostatistical model was fitted, which assumes an underlying geologically determined spatial variation, superimposed on which is a Gaussian stochastic process with Matern correlation structure that models the observed tendency of dose rates in neighbouring houses to correlate. In the second approach, a number of dose-rate interpolation measures were first derived, based on averages over geologically or administratively defined areas or using distance-weighted averages of measurements at nearest-neighbour points. Linear regression was then used to derive an optimal linear combination of these interpolation measures. The predictive performances of the two models were compared via cross-validation, using a randomly selected 70 % of the data to fit the models and the remaining 30 % to test them. The mean square error (MSE) of the linear-regression model was lower than that of the Gaussian-Matern model (MSE 378 and 411, respectively). The predictive performance of the two candidate models was also evaluated via simulation; the OLS model performs significantly better than the Gaussian-Matern model. (orig.)

  15. Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

    Science.gov (United States)

    Denkins, Pamela; Badhwar, Gautam; Obot, Victor; Wilson, Bobby; Jejelewo, Olufisayo

    2001-08-01

    NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far, the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space, exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

  16. Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

    Science.gov (United States)

    Denkins, P.; Badhwar, G.; Obot, V.; Wilson, B.; Jejelewo, O.

    2001-01-01

    NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far. the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space. exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

  17. Prediction of UV spectra and UV-radiation damage in actual plasma etching processes using on-wafer monitoring technique

    International Nuclear Information System (INIS)

    Jinnai, Butsurin; Fukuda, Seiichi; Ohtake, Hiroto; Samukawa, Seiji

    2010-01-01

    UV radiation during plasma processing affects the surface of materials. Nevertheless, the interaction of UV photons with surface is not clearly understood because of the difficulty in monitoring photons during plasma processing. For this purpose, we have previously proposed an on-wafer monitoring technique for UV photons. For this study, using the combination of this on-wafer monitoring technique and a neural network, we established a relationship between the data obtained from the on-wafer monitoring technique and UV spectra. Also, we obtained absolute intensities of UV radiation by calibrating arbitrary units of UV intensity with a 126 nm excimer lamp. As a result, UV spectra and their absolute intensities could be predicted with the on-wafer monitoring. Furthermore, we developed a prediction system with the on-wafer monitoring technique to simulate UV-radiation damage in dielectric films during plasma etching. UV-induced damage in SiOC films was predicted in this study. Our prediction results of damage in SiOC films shows that UV spectra and their absolute intensities are the key cause of damage in SiOC films. In addition, UV-radiation damage in SiOC films strongly depends on the geometry of the etching structure. The on-wafer monitoring technique should be useful in understanding the interaction of UV radiation with surface and in optimizing plasma processing by controlling UV radiation.

  18. SU-F-P-20: Predicting Waiting Times in Radiation Oncology Using Machine Learning

    International Nuclear Information System (INIS)

    Joseph, A; Herrera, D; Hijal, T; Kildea, J; Hendren, L; Leung, A; Wainberg, J; Sawaf, M; Gorshkov, M; Maglieri, R; Keshavarz, M

    2016-01-01

    Purpose: Waiting times remain one of the most vexing patient satisfaction challenges facing healthcare. Waiting time uncertainty can cause patients, who are already sick or in pain, to worry about when they will receive the care they need. These waiting periods are often difficult for staff to predict and only rough estimates are typically provided based on personal experience. This level of uncertainty leaves most patients unable to plan their calendar, making the waiting experience uncomfortable, even painful. In the present era of electronic health records (EHRs), waiting times need not be so uncertain. Extensive EHRs provide unprecedented amounts of data that can statistically cluster towards representative values when appropriate patient cohorts are selected. Predictive modelling, such as machine learning, is a powerful approach that benefits from large, potentially complex, datasets. The essence of machine learning is to predict future outcomes by learning from previous experience. The application of a machine learning algorithm to waiting time data has the potential to produce personalized waiting time predictions such that the uncertainty may be removed from the patient’s waiting experience. Methods: In radiation oncology, patients typically experience several types of waiting (eg waiting at home for treatment planning, waiting in the waiting room for oncologist appointments and daily waiting in the waiting room for radiotherapy treatments). A daily treatment wait time model is discussed in this report. To develop a prediction model using our large dataset (with more than 100k sample points) a variety of machine learning algorithms from the Python package sklearn were tested. Results: We found that the Random Forest Regressor model provides the best predictions for daily radiotherapy treatment waiting times. Using this model, we achieved a median residual (actual value minus predicted value) of 0.25 minutes and a standard deviation residual of 6.5 minutes

  19. SU-F-P-20: Predicting Waiting Times in Radiation Oncology Using Machine Learning

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, A; Herrera, D; Hijal, T; Kildea, J [McGill University Health Centre, Montreal, Quebec (Canada); Hendren, L; Leung, A; Wainberg, J; Sawaf, M; Gorshkov, M; Maglieri, R; Keshavarz, M [McGill University, Montreal, Quebec (Canada)

    2016-06-15

    Purpose: Waiting times remain one of the most vexing patient satisfaction challenges facing healthcare. Waiting time uncertainty can cause patients, who are already sick or in pain, to worry about when they will receive the care they need. These waiting periods are often difficult for staff to predict and only rough estimates are typically provided based on personal experience. This level of uncertainty leaves most patients unable to plan their calendar, making the waiting experience uncomfortable, even painful. In the present era of electronic health records (EHRs), waiting times need not be so uncertain. Extensive EHRs provide unprecedented amounts of data that can statistically cluster towards representative values when appropriate patient cohorts are selected. Predictive modelling, such as machine learning, is a powerful approach that benefits from large, potentially complex, datasets. The essence of machine learning is to predict future outcomes by learning from previous experience. The application of a machine learning algorithm to waiting time data has the potential to produce personalized waiting time predictions such that the uncertainty may be removed from the patient’s waiting experience. Methods: In radiation oncology, patients typically experience several types of waiting (eg waiting at home for treatment planning, waiting in the waiting room for oncologist appointments and daily waiting in the waiting room for radiotherapy treatments). A daily treatment wait time model is discussed in this report. To develop a prediction model using our large dataset (with more than 100k sample points) a variety of machine learning algorithms from the Python package sklearn were tested. Results: We found that the Random Forest Regressor model provides the best predictions for daily radiotherapy treatment waiting times. Using this model, we achieved a median residual (actual value minus predicted value) of 0.25 minutes and a standard deviation residual of 6.5 minutes

  20. Predicting commuter flows in spatial networks using a radiation model based on temporal ranges

    Science.gov (United States)

    Ren, Yihui; Ercsey-Ravasz, Mária; Wang, Pu; González, Marta C.; Toroczkai, Zoltán

    2014-11-01

    Understanding network flows such as commuter traffic in large transportation networks is an ongoing challenge due to the complex nature of the transportation infrastructure and human mobility. Here we show a first-principles based method for traffic prediction using a cost-based generalization of the radiation model for human mobility, coupled with a cost-minimizing algorithm for efficient distribution of the mobility fluxes through the network. Using US census and highway traffic data, we show that traffic can efficiently and accurately be computed from a range-limited, network betweenness type calculation. The model based on travel time costs captures the log-normal distribution of the traffic and attains a high Pearson correlation coefficient (0.75) when compared with real traffic. Because of its principled nature, this method can inform many applications related to human mobility driven flows in spatial networks, ranging from transportation, through urban planning to mitigation of the effects of catastrophic events.

  1. Analytical Prediction of the Spin Stabilized Satellite's Attitude Using The Solar Radiation Torque

    International Nuclear Information System (INIS)

    Motta, G B; Carvalho, M V; Zanardi, M C

    2013-01-01

    The aim of this paper is to present an analytical solution for the spin motion equations of spin-stabilized satellite considering only the influence of solar radiation torque. The theory uses a cylindrical satellite on a circular orbit and considers that the satellite is always illuminated. The average components of this torque were determined over an orbital period. These components are substituted in the spin motion equations in order to get an analytical solution for the right ascension and declination of the satellite spin axis. The time evolution for the pointing deviation of the spin axis was also analyzed. These solutions were numerically implemented and compared with real data of the Brazilian Satellite of Data Collection – SCD1 an SCD2. The results show that the theory has consistency and can be applied to predict the spin motion of spin-stabilized artificial satellites

  2. Prediction of hardness of the Zn-Al-Cu alloys of agreement by composition in weight; Prediccion de la dureza de la aleacion Zn-Al-Cu de acuerdo a su composicion en peso

    Energy Technology Data Exchange (ETDEWEB)

    Villegas-Cardenas, Jose David; Camarillo-Villegas, Alejandra; Juanico-Loran, Antonio [Universidad Politecnica del Valle de Mexico, Tultitlan, Estado de Mexico (Mexico)]. E-mails: jdvc76@yahoo.com.mx; v_c_a_77@hotmail.com; ajuanico@yahoo.com.mx; Espinosa-Rojas, Raul [Universidad Autonoma Metropolitana, Unidad Azcapotzalco (Mexico)]. E-mail: rer21@hotmail.com; Camacho-Olguin, Carlos [Universidad Politecnica del Valle de Mexico, Tultitlan, Estado de Mexico (Mexico)]. E-mail: ccamacho@upvm.edu.mx

    2013-07-15

    Ten alloys Zn-Al-Cu were developed in two parts, in agreement to two zones presented in the isopleth diagrams (Villas et al., 1995). The percentage of Cu and Al was systematically varied. Subsequently, hardness measurements were performed. These measurements allowed establishing two equations that predict the hardness with an error lower than 5%. With these equations, it is possible to obtain alloys that replace Al base alloys by a Zn base alloy, having the same hardness. This implicates also the elimination of the volumetric change in the presence of e phase. [Spanish] Se desarrollaron diez aleaciones Zn-Al-Cu divididas en dos partes, de acuerdo a dos zonas presentadas en los diagramas isopleticos de Hans (Villas et al., 1995). Se incremento el porcentaje de Cu y Al paulatinamente. Posteriormente se desarrollaron pruebas de macrodureza y de ese analisis se obtuvieron dos ecuaciones que permiten pronosticar y disenar aleaciones de una dureza determinada de acuerdo a su porcentaje en peso de cada elemento, con un error menor que 5%. Como se demuestra en este trabajo, con estas ecuaciones es posible desarrollar aleaciones sustitutas base aluminio por una aleacion base zinc o viceversa, teniendo la misma dureza para cada tipo de aleacion y eliminando el problema del cambio volumetrico debido a la presencia de la fase e.

  3. An Easy Tool to Predict Survival in Patients Receiving Radiation Therapy for Painful Bone Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Westhoff, Paulien G., E-mail: p.g.westhoff@umcutrecht.nl [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Graeff, Alexander de [Department of Medical Oncology, University Medical Center Utrecht, Utrecht (Netherlands); Monninkhof, Evelyn M. [Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht (Netherlands); Bollen, Laurens; Dijkstra, Sander P. [Department of Orthopedic Surgery, Leiden University Medical Center (Netherlands); Steen-Banasik, Elzbieta M. van der [ARTI Institute for Radiation Oncology Arnhem, Arnhem (Netherlands); Vulpen, Marco van [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Leer, Jan Willem H. [Department of Radiotherapy, University Medical Center Nijmegen, Nijmegen (Netherlands); Marijnen, Corrie A.; Linden, Yvette M. van der [Department of Clinical Oncology, Leiden University Medical Center, Leiden (Netherlands)

    2014-11-15

    Purpose: Patients with bone metastases have a widely varying survival. A reliable estimation of survival is needed for appropriate treatment strategies. Our goal was to assess the value of simple prognostic factors, namely, patient and tumor characteristics, Karnofsky performance status (KPS), and patient-reported scores of pain and quality of life, to predict survival in patients with painful bone metastases. Methods and Materials: In the Dutch Bone Metastasis Study, 1157 patients were treated with radiation therapy for painful bone metastases. At randomization, physicians determined the KPS; patients rated general health on a visual analogue scale (VAS-gh), valuation of life on a verbal rating scale (VRS-vl) and pain intensity. To assess the predictive value of the variables, we used multivariate Cox proportional hazard analyses and C-statistics for discriminative value. Of the final model, calibration was assessed. External validation was performed on a dataset of 934 patients who were treated with radiation therapy for vertebral metastases. Results: Patients had mainly breast (39%), prostate (23%), or lung cancer (25%). After a maximum of 142 weeks' follow-up, 74% of patients had died. The best predictive model included sex, primary tumor, visceral metastases, KPS, VAS-gh, and VRS-vl (C-statistic = 0.72, 95% CI = 0.70-0.74). A reduced model, with only KPS and primary tumor, showed comparable discriminative capacity (C-statistic = 0.71, 95% CI = 0.69-0.72). External validation showed a C-statistic of 0.72 (95% CI = 0.70-0.73). Calibration of the derivation and the validation dataset showed underestimation of survival. Conclusion: In predicting survival in patients with painful bone metastases, KPS combined with primary tumor was comparable to a more complex model. Considering the amount of variables in complex models and the additional burden on patients, the simple model is preferred for daily use. In addition, a risk table for survival is

  4. Predicting Downward Longwave Radiation for Various Land Use in All-Sky Condition: Northeast Florida

    Directory of Open Access Journals (Sweden)

    Chi-Han Cheng

    2014-01-01

    Full Text Available Accurate estimate of the surface longwave radiation is important for the surface radiation budget, which in turn controls evaporation and sensible heat fluxes. Regional land use changes can impact local weather conditions; for example, heterogeneous land use patterns and temporal changes in atmospheric circulation patterns would affect air temperature and water vapor pressure, which are more commonly used as inputs in existing models for estimating downward longwave radiation (LWd. In this study, first, we analyzed the cloud cover and land use covers impacts on LWd. Next, LWd on all-sky conditions were developed by using the existing land use-adapted model and cloud cover data from the region of Saint Johns River Water Management District (SJRWMD, FL. The results show that factors, such as, seasonal effects, cloud cover, and land use, are of importance in the estimation of LWd and they cannot be ignored when developing a model for LWd prediction. The all-sky land use-adapted model with all factors taken into account performs better than other existing models statistically. The results of the statistical analyses indicated that the BIAS, RMSE, MAE, and PMRE are −0.18 Wm−2, 10.81 Wm−2, 8.00 Wm−2, and 2.30%; −2.61 Wm−2, 14.45 Wm−2, 10.64 Wm−2, and 3.19%; −0.07 Wm−2, 10.53 Wm−2, 8.03 Wm−2, and 2.27%; and −0.62 Wm−2, 13.97 Wm−2, 9.76 Wm−2, and 2.87% for urban, rangeland, agricultural, and wetland areas, respectively.

  5. Age-adjusted Charlson Comorbidity Index predicts prognosis of laryngopharyngeal cancer treated with radiation therapy.

    Science.gov (United States)

    Takemura, Kazuya; Takenaka, Yukinori; Ashida, Naoki; Shimizu, Kotaro; Oya, Ryohei; Kitamura, Takahiro; Yamamoto, Yoshifumi; Uno, Atsuhiko

    2017-12-01

    To examine the ability of comorbidity indices to predict the prognosis of laryngopharyngeal cancer and their association with treatment modalities. This retrospective study included 198 patients with laryngeal, hypopharyngeal, and oropharyngeal cancers. The effect of comorbidity indices on overall survival between surgery and (chemo)-radiation therapy ((C)RT) groups was analyzed. The cumulative incidence rates for cancer mortality and other mortalities according to the age-adjusted Charlson Comorbidity Index (ACCI) and Charlson Comorbidity Index (CCI) were compared. Univariate survival analyses showed a significant association between the ACCI and overall survival in the (C)RT group, but not in the surgery group. The association between the CCI and overall survival was not significant in either group. In multivariate analyses, a high ACCI score was an independent prognostic factor in the (C)RT group (HR 2.89, 95% confidence interval (CI) 1.28-6.49), but not in the surgery group (HR 1.39, 95%CI 0.27-5.43). The higher ACCI group had increased mortality from other causes compared with the lower ACCI group (5-year cumulative incidence, 8.5% and 17.8%, respectively, p = .003). The ACCI was a better prognostic factor than the CCI. Surgery may be more beneficial than radiation for patients with a high ACCI.

  6. Predicting the components of the total hemispherical solar radiation from sunshine duration measurements in Lagos, Nigeria

    International Nuclear Information System (INIS)

    Maduekwe, A.A.L.; Chendo, M.A.C.

    1994-06-01

    Correlations for the city of Lagos (latitude 6.58 deg. N, longitude 3.33 deg. E) have been found between the records of bright sunshine hours and the daily and monthly components of the total hemispherical solar radiation. Four new models have been developed which include H/H 0 as a predictor in the Angstrom type models for the diffuse and beam fractions. They contain the quadratic term of the sunshine index, (n/N) and are given as follows: Q/H 0 =a+b(H/H 0 )+c(n/N)+d(n/N) 2 Q/H 0 =a+b(H/H 0 )+d(n/N) 2 ; Q/H 0 =a+b(H/H 0 )+c(n/N)+d(n/N) 2 ; Q/H 0 =a+b(H/H 0 )+d(n/N) 2 ; where Q is the diffuse or beam radiation on a horizontal plane. The statistical test carried out showed that the new equations generally improved the prediction of the beam or diffuse components from the Angstrom type equations by over 25%. (author). 21 refs, 3 tabs

  7. Predicting thermal distortion of synchrotron radiation mirrors with finite element analysis

    International Nuclear Information System (INIS)

    DiGennaro, R.; Edwards, W.R.; Hoyer, E.

    1985-10-01

    High power and high power densities due to absorbed radiation are significant design considerations which can limit performance of mirrors receiving highly collimated synchrotron radiation from insertion devices and bending magnet sources. Although the grazing incidence angles needed for x-ray optics spread the thermal load, localized, non-uniform heating can cause distortions which exceed allowable surface figure errors and limit focusing resolution. This paper discusses the suitability of numerical approximations using finite element methods for heat transfer, deformation, and stress analysis of optical elements. The primary analysis objectives are (1) to estimate optical surface figure under maximum heat loads, (2) to correctly predict thermal stresses in order to select suitable materials and mechanical design configurations, and (3) to minimize fabrication costs by specifying appropriate tolerances for surface figure. Important factors which determine accuracy of results include finite element model mesh refinement, accuracy of boundary condition modeling, and reliability of material property data. Some methods to verify accuracy are suggested. Design analysis for an x-ray mirror is presented. Some specific configurations for internal water-cooling are evaluated in order to determine design sensitivity with respect to structural geometry, material properties, fabrication tolerances, absorbed heat magnitude and distribution, and heat transfer approximations. Estimated accuracy of these results is discussed

  8. Towards Relaxing the Spherical Solar Radiation Pressure Model for Accurate Orbit Predictions

    Science.gov (United States)

    Lachut, M.; Bennett, J.

    2016-09-01

    The well-known cannonball model has been used ubiquitously to capture the effects of atmospheric drag and solar radiation pressure on satellites and/or space debris for decades. While it lends itself naturally to spherical objects, its validity in the case of non-spherical objects has been debated heavily for years throughout the space situational awareness community. One of the leading motivations to improve orbit predictions by relaxing the spherical assumption, is the ongoing demand for more robust and reliable conjunction assessments. In this study, we explore the orbit propagation of a flat plate in a near-GEO orbit under the influence of solar radiation pressure, using a Lambertian BRDF model. Consequently, this approach will account for the spin rate and orientation of the object, which is typically determined in practice using a light curve analysis. Here, simulations will be performed which systematically reduces the spin rate to demonstrate the point at which the spherical model no longer describes the orbital elements of the spinning plate. Further understanding of this threshold would provide insight into when a higher fidelity model should be used, thus resulting in improved orbit propagations. Therefore, the work presented here is of particular interest to organizations and researchers that maintain their own catalog, and/or perform conjunction analyses.

  9. Role of electroweak radiation in predictions for dark matter indirect detection

    Energy Technology Data Exchange (ETDEWEB)

    Ali Cavasonza, Leila; Pellen, Mathieu; Kraemer, Michael [RWTH Aachen, Aachen (Germany)

    2015-07-01

    A very exciting challenge in particle and astroparticle physics is the exploration of the nature of dark matter. The evidences of the existence of dark matter are also the strongest phenomenological indications for physics beyond the Standard Model. A huge experimental effort is currently made at colliders and via astrophysical experiments to shed light on the nature of dark matter: dark matter may be produced at colliders or detected through direct and indirect detection experiments. The interplay and complementarity between these different approaches offers extraordinary opportunities to improve our understanding of the nature of dark matter or to set constraints on dark matter models. In indirect detection one searches for dark matter annihilation products, that produce secondary antimatter particles like positrons and antiprotons. Such antimatter particles propagate through the Galaxy and can be detected at Earth by astrophysical experiments. Particularly interesting is the importance of electroweak corrections to the predictions for the expected fluxes at Earth. The inclusion of EW radiation from the primary dark matter annihilation products can significantly affect the spectra of the secondary SM particles. The EW radiation can be described using fragmentation functions, as done for instance in QCD. We study the quality of this approximation in a simplified SUSY model and in a UED model.

  10. Pre-radiotherapy FDG PET predicts radiation pneumonitis in lung cancer

    International Nuclear Information System (INIS)

    Castillo, Richard; Guerrero, Thomas; Pham, Ngoc; Ansari, Sobiya; Meshkov, Dmitriy; Castillo, Sarah; Li, Min; Olanrewaju, Adenike; Hobbs, Brian; Castillo, Edward

    2014-01-01

    A retrospective analysis is performed to determine if pre-treatment [ 18 F]-2-fluoro-2-deoxyglucose positron emission tomography/computed tomography (FDG PET/CT) image derived parameters can predict radiation pneumonitis (RP) clinical symptoms in lung cancer patients. We retrospectively studied 100 non-small cell lung cancer (NSCLC) patients who underwent FDG PET/CT imaging before initiation of radiotherapy (RT). Pneumonitis symptoms were evaluated using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv4) from the consensus of 5 clinicians. Using the cumulative distribution of pre-treatment standard uptake values (SUV) within the lungs, the 80th to 95th percentile SUV values (SUV 80 to SUV 95 ) were determined. The effect of pre-RT FDG uptake, dose, patient and treatment characteristics on pulmonary toxicity was studied using multiple logistic regression. The study subjects were treated with 3D conformal RT (n = 23), intensity modulated RT (n = 64), and proton therapy (n = 13). Multiple logistic regression analysis demonstrated that elevated pre-RT lung FDG uptake on staging FDG PET was related to development of RP symptoms after RT. A patient of average age and V 30 with SUV 95 = 1.5 was an estimated 6.9 times more likely to develop grade ≥ 2 radiation pneumonitis when compared to a patient with SUV 95 = 0.5 of the same age and identical V 30 . Receiver operating characteristic curve analysis showed the area under the curve was 0.78 (95% CI = 0.69 – 0.87). The CT imaging and dosimetry parameters were found to be poor predictors of RP symptoms. The pretreatment pulmonary FDG uptake, as quantified by the SUV 95 , predicted symptoms of RP in this study. Elevation in this pre-treatment biomarker identifies a patient group at high risk for post-treatment symptomatic RP

  11. Bayesian network ensemble as a multivariate strategy to predict radiation pneumonitis risk

    International Nuclear Information System (INIS)

    Lee, Sangkyu; Ybarra, Norma; Jeyaseelan, Krishinima; Seuntjens, Jan; El Naqa, Issam; Faria, Sergio; Kopek, Neil; Brisebois, Pascale; Bradley, Jeffrey D.; Robinson, Clifford

    2015-01-01

    Purpose: Prediction of radiation pneumonitis (RP) has been shown to be challenging due to the involvement of a variety of factors including dose–volume metrics and radiosensitivity biomarkers. Some of these factors are highly correlated and might affect prediction results when combined. Bayesian network (BN) provides a probabilistic framework to represent variable dependencies in a directed acyclic graph. The aim of this study is to integrate the BN framework and a systems’ biology approach to detect possible interactions among RP risk factors and exploit these relationships to enhance both the understanding and prediction of RP. Methods: The authors studied 54 nonsmall-cell lung cancer patients who received curative 3D-conformal radiotherapy. Nineteen RP events were observed (common toxicity criteria for adverse events grade 2 or higher). Serum concentration of the following four candidate biomarkers were measured at baseline and midtreatment: alpha-2-macroglobulin, angiotensin converting enzyme (ACE), transforming growth factor, interleukin-6. Dose-volumetric and clinical parameters were also included as covariates. Feature selection was performed using a Markov blanket approach based on the Koller–Sahami filter. The Markov chain Monte Carlo technique estimated the posterior distribution of BN graphs built from the observed data of the selected variables and causality constraints. RP probability was estimated using a limited number of high posterior graphs (ensemble) and was averaged for the final RP estimate using Bayes’ rule. A resampling method based on bootstrapping was applied to model training and validation in order to control under- and overfit pitfalls. Results: RP prediction power of the BN ensemble approach reached its optimum at a size of 200. The optimized performance of the BN model recorded an area under the receiver operating characteristic curve (AUC) of 0.83, which was significantly higher than multivariate logistic regression (0

  12. Bayesian network ensemble as a multivariate strategy to predict radiation pneumonitis risk

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sangkyu, E-mail: sangkyu.lee@mail.mcgill.ca; Ybarra, Norma; Jeyaseelan, Krishinima; Seuntjens, Jan; El Naqa, Issam [Medical Physics Unit, McGill University, Montreal, Quebec H3G1A4 (Canada); Faria, Sergio; Kopek, Neil; Brisebois, Pascale [Department of Radiation Oncology, Montreal General Hospital, Montreal, H3G1A4 (Canada); Bradley, Jeffrey D.; Robinson, Clifford [Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri 63110 (United States)

    2015-05-15

    Purpose: Prediction of radiation pneumonitis (RP) has been shown to be challenging due to the involvement of a variety of factors including dose–volume metrics and radiosensitivity biomarkers. Some of these factors are highly correlated and might affect prediction results when combined. Bayesian network (BN) provides a probabilistic framework to represent variable dependencies in a directed acyclic graph. The aim of this study is to integrate the BN framework and a systems’ biology approach to detect possible interactions among RP risk factors and exploit these relationships to enhance both the understanding and prediction of RP. Methods: The authors studied 54 nonsmall-cell lung cancer patients who received curative 3D-conformal radiotherapy. Nineteen RP events were observed (common toxicity criteria for adverse events grade 2 or higher). Serum concentration of the following four candidate biomarkers were measured at baseline and midtreatment: alpha-2-macroglobulin, angiotensin converting enzyme (ACE), transforming growth factor, interleukin-6. Dose-volumetric and clinical parameters were also included as covariates. Feature selection was performed using a Markov blanket approach based on the Koller–Sahami filter. The Markov chain Monte Carlo technique estimated the posterior distribution of BN graphs built from the observed data of the selected variables and causality constraints. RP probability was estimated using a limited number of high posterior graphs (ensemble) and was averaged for the final RP estimate using Bayes’ rule. A resampling method based on bootstrapping was applied to model training and validation in order to control under- and overfit pitfalls. Results: RP prediction power of the BN ensemble approach reached its optimum at a size of 200. The optimized performance of the BN model recorded an area under the receiver operating characteristic curve (AUC) of 0.83, which was significantly higher than multivariate logistic regression (0

  13. IL-6 is a potential marker for radiation pneumonitis: a prospective clinical study of circulating cytokines in predicting radiation pulmonary injury

    International Nuclear Information System (INIS)

    Chen Yuhchyau; Rubin, Philip; McDonald, Sandra; Finkelstein, Jacob; Smudzin, Therese; Hernady, Eric; Williams, Jacqueline

    1997-01-01

    Purpose/Objective: The use of radiotherapy in eradicating thoracic malignancy is limited by the normal lung tissue tolerance to ionizing radiation. Subacute and late radiation pulmonary toxicity manifests as radiation pneumonitis and ultimately lung fibrosis. Recently, the addition of chemotherapy or a biologic response modifier to radiation has become the standard therapy for inoperable lung cancer. The radiosensitizing effect of these agents is associated with an increased risk of radiation pulmonary injury and treatment related mortality. The search for a serum marker for predicting radiation pulmonary injury will help us understand the mechanism leading to such events and find possible interventions to prevent the adverse outcome. Unpublished data from our laboratory suggested that following a single dose of radiation, there was a dose-related elevation in IL-6 protein levels in the lung of radiation fibrosis prone mice. Based on this information, a prospective clinical study of circulating cytokine levels and its application to predict radiation induced pulmonary injury was conducted at University of Rochester. Preliminary results revealed promising information in identifying a circulating cytokine as a predictor for radiation pneumonitis. Materials and Methods: Eighteen patients receiving thoracic irradiation for primary thoracic malignancy were registered in the study. Radiation pneumonitis was determined by subjective respiratory symptoms assessed according to RTOG morbidity scoring criteria. Pretreatment and serial post-therapy chest X-ray, chest CT scan and pulmonary function tests were obtained. Radiation fibrosis was determined by radiographic changes in irradiated normal lung using a scoring system which quantified the extent of loss of air content, degree of opacification, anatomic extent of involvement, air bronchogram, pleural thickening, or effusion. Plasma levels of interleukin-6 (IL-6), tumor necrosis factor (TNF), transforming growth factor

  14. Possibility of coherent hard x-ray production by pumping with synchrotron radiation and low energy photons. Period covered: November 17, 1976--August 16, 1977

    International Nuclear Information System (INIS)

    Csonka, P.L.

    1977-01-01

    Coherent x-rays in the keV range could be produced by pumping a suitable gas with synchrotron radiation in combination with low energy photon beams in the presence of appropriately arranged mirrors. With a wiggler magnet placed in the low beta section of the PEP machine to be constructed at Stanford, 1020 eV coherent photons could be produced from Ne. Appropriate synchrotron radiation will produce a highly ionized cool gas. Low energy photons modify the outer electron structure of ions to enhance lasing: they modify the lifetime of the inverted state, counterbalance unwanted collisionally induced transitions, reduce Stark line broadening

  15. Space Radiation Environment Prediction for VLSI microelectronics devices onboard a LEO Satellite using OMERE-Trad Software

    Science.gov (United States)

    Sajid, Muhammad

    This tutorial/survey paper presents the assessment/determination of level of hazard/threat to emerging microelectronics devices in Low Earth Orbit (LEO) space radiation environment with perigee at 300 Km, apogee at 600Km altitude having different orbital inclinations to predict the reliability of onboard Bulk Built-In Current Sensor (BBICS) fabricated in 350nm technology node at OptMA Lab. UFMG Brazil. In this context, the various parameters for space radiation environment have been analyzed to characterize the ionizing radiation environment effects on proposed BBICS. The Space radiation environment has been modeled in the form of particles trapped in Van-Allen radiation belts(RBs), Energetic Solar Particles Events (ESPE) and Galactic Cosmic Rays (GCR) where as its potential effects on Device- Under-Test (DUT) has been predicted in terms of Total Ionizing Dose (TID), Single-Event Effects (SEE) and Displacement Damage Dose (DDD). Finally, the required mitigation techniques including necessary shielding requirements to avoid undesirable effects of radiation environment at device level has been estimated /determined with assumed standard thickness of Aluminum shielding. In order to evaluate space radiation environment and analyze energetic particles effects on BBICS, OMERE toolkit developed by TRAD was utilized.

  16. Scoring system predictive of survival for patients undergoing stereotactic body radiation therapy for liver tumors

    Directory of Open Access Journals (Sweden)

    Kress Marie-Adele S

    2012-09-01

    Full Text Available Abstract Background Stereotactic body radiation therapy (SBRT is an emerging treatment option for liver tumors. This study evaluated outcomes after SBRT to identify prognostic variables and to develop a novel scoring system predictive of survival. Methods The medical records of 52 patients with a total of 85 liver lesions treated with SBRT from 2003 to 2010 were retrospectively reviewed. Twenty-four patients had 1 lesion; 27 had 2 or more. Thirteen lesions were primary tumors; 72 were metastases. Fiducials were placed in all patients prior to SBRT. The median prescribed dose was 30 Gy (range, 16 – 50 Gy in a median of 3 fractions (range, 1–5. Results With median follow-up of 11.3 months, median overall survival (OS was 12.5 months, and 1 year OS was 50.8%. In 42 patients with radiographic follow up, 1 year local control was 74.8%. On univariate analysis, number of lesions (p = 0.0243 and active extralesional disease (p  Conclusions SBRT offers a safe and feasible treatment option for liver tumors. A prognostic scoring system based on the number of liver lesions, activity of extralesional disease, and KPS predicts survival following SBRT and can be used as a guide for prospective validation and ultimately for treatment decision-making.

  17. Prediction Model of the Outer Radiation Belt Developed by Chungbuk National University

    Directory of Open Access Journals (Sweden)

    Dae-Kyu Shin

    2014-12-01

    Full Text Available The Earth’s outer radiation belt often suffers from drastic changes in the electron fluxes. Since the electrons can be a potential threat to satellites, efforts have long been made to model and predict electron flux variations. In this paper, we describe a prediction model for the outer belt electrons that we have recently developed at Chungbuk National University. The model is based on a one-dimensional radial diffusion equation with observationally determined specifications of a few major ingredients in the following way. First, the boundary condition of the outer edge of the outer belt is specified by empirical functions that we determine using the THEMIS satellite observations of energetic electrons near the boundary. Second, the plasmapause locations are specified by empirical functions that we determine using the electron density data of THEMIS. Third, the model incorporates the local acceleration effect by chorus waves into the one-dimensional radial diffusion equation. We determine this chorus acceleration effect by first obtaining an empirical formula of chorus intensity as a function of drift shell parameter L*, incorporating it as a source term in the one-dimensional diffusion equation, and lastly calibrating the term to best agree with observations of a certain interval. We present a comparison of the model run results with and without the chorus acceleration effect, demonstrating that the chorus effect has been incorporated into the model to a reasonable degree.

  18. Standard Test Method for Application of Ionization Chambers to Assess the Low Energy Gamma Component of Cobalt-60 Irradiators Used in Radiation-Hardness Testing of Silicon Electronic Devices

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 Low energy components in the photon energy spectrum of Co-60 irradiators lead to absorbed dose enhancement effects in the radiation-hardness testing of silicon electronic devices. These low energy components may lead to errors in determining the absorbed dose in a specific device under test. This method covers procedures for the use of a specialized ionization chamber to determine a figure of merit for the relative importance of such effects. It also gives the design and instructions for assembling this chamber. 1.2 This method is applicable to measurements in Co-60 radiation fields where the range of exposure rates is 7 × 10 −6 to 3 × 10−2 C kg −1 s−1 (approximately 100 R/h to 100 R/s). For guidance in applying this method to radiation fields where the exposure rate is >100 R/s, see Appendix X1. Note 1—See Terminology E170 for definition of exposure and its units. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information onl...

  19. Evaluation of radiation effects on dental enamel hardness and dental restorative materials; Avaliacao do efeito da irradiacao na dureza do esmalte dental e de materiais odontologicos

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Lena Katekawa; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica; Campos, Tomie Nakakuki [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia. Dept. de Protese

    2000-07-01

    This research presents the results of the microhardness of human dental enamel and of the following dental restorative materials: three dental porcelains - Ceramco II, Finesse and Noritake, and two resin restorative materials - Artglass and Targis, for materials submitted to different times of irradiation at the IEA-R1m nuclear reactor under a thermal neutron flux of 10{sup 12}n cm{sup -2}.s{sup -1} . The results obtained indicated that there is a decrease of the surface microhardness when the enamel is irradiated for 1 h and when dental materials are irradiated for 3 h. However, enamels irradiated for 30 min. did not show significant change of their surface hardness. Therefore, the selection of irradiation time is an important factor to be considered when irradiated teeth or dental materials are used in the investigations of their properties. (author)

  20. A Nonlinear Autoregressive Exogenous (NARX Neural Network Model for the Prediction of the Daily Direct Solar Radiation

    Directory of Open Access Journals (Sweden)

    Zina Boussaada

    2018-03-01

    Full Text Available The solar photovoltaic (PV energy has an important place among the renewable energy sources. Therefore, several researchers have been interested by its modelling and its prediction, in order to improve the management of the electrical systems which include PV arrays. Among the existing techniques, artificial neural networks have proved their performance in the prediction of the solar radiation. However, the existing neural network models don’t satisfy the requirements of certain specific situations such as the one analyzed in this paper. The aim of this research work is to supply, with electricity, a race sailboat using exclusively renewable sources. The developed solution predicts the direct solar radiation on a horizontal surface. For that, a Nonlinear Autoregressive Exogenous (NARX neural network is used. All the specific conditions of the sailboat operation are taken into account. The results show that the best prediction performance is obtained when the training phase of the neural network is performed periodically.

  1. Analysis of the value of post-radiation prostate biopsy in predicting subsequent disease progression

    International Nuclear Information System (INIS)

    Benda, R.; Shamsa, F.; Meetze, K.; Bolton, S.; Littrup, P.; Grignon, D.; Washington, T.; Forman, J.D.

    1997-01-01

    Purpose: To analyze the value of Transrectal ultrasound(TRUS), Color flow doppler(CFD) and Prostate specific antigen(PSA) in identifying residual disease in the prostate status post external beam radiation therapy and to determine the value of this pathologic information in predicting subsequent disease progression. Materials and Methods: As part of four prospective protocols, 146 patients had scheduled TRUS guided prostate biopsies 6-25 months status post radiation therapy. The stage distribution was: 13% T1, 51% T2, and 36% T3/T4. Fifty six percent had neo-adjuvant hormones. Conformal photon or mixed neutron/photon irradiation was given to a median 2 Gy/fraction equivalent dose of 77 Gy(range 74 to 84 Gy). Following treatment, patients were assessed by digital rectal exam (DRE), PSA and TRUS guided biopsies at 6, 12 and/or 18 months. The ultrasound and CFD results were scored as normal, suspicious or abnormal. Sextant biopsies were obtained as well as ultrasound guided biopsies from any abnormal ultrasound or doppler area. The biopsies, all read by one pathologist (DG), were graded as negative, marked, moderate, minimal therapeutic effect or positive. The median followup post radiation therapy was 33.6 months and post biopsy was 25.3 months. Comparisons were done by Kappa index with corresponding 95% CI, chi square and Fisher's exact tests. Results: Twenty-eight patients had biopsies at both six and 12-18 months. Overall 35% of patients had all negative cores, 30% had at least one core showing a marked therapeutic effect, and 35% had at least one core showing moderate or minimal therapeutic effect or were positive. Although CFD correlated with a positive biopsy in 9% and a suspicious doppler identified cancer in 15% of cases, an abnormal TRUS identified cancer in 29.5% biopsies ((49(166))). However, a serum PSA >1.5ng/ml at the time of biopsy predicted 61% of positive biopsies ((23(38))). A negative biopsy was associated with low stage (≤T2c, p=0.001), low pre

  2. Ultra-low power high temperature and radiation hard complementary metal-oxide-semiconductor (CMOS) silicon-on-insulator (SOI) voltage reference.

    Science.gov (United States)

    Boufouss, El Hafed; Francis, Laurent A; Kilchytska, Valeriya; Gérard, Pierre; Simon, Pascal; Flandre, Denis

    2013-12-13

    This paper presents an ultra-low power CMOS voltage reference circuit which is robust under biomedical extreme conditions, such as high temperature and high total ionized dose (TID) radiation. To achieve such performances, the voltage reference is designed in a suitable 130 nm Silicon-on-Insulator (SOI) industrial technology and is optimized to work in the subthreshold regime of the transistors. The design simulations have been performed over the temperature range of -40-200 °C and for different process corners. Robustness to radiation was simulated using custom model parameters including TID effects, such as mobilities and threshold voltages degradation. The proposed circuit has been tested up to high total radiation dose, i.e., 1 Mrad (Si) performed at three different temperatures (room temperature, 100 °C and 200 °C). The maximum drift of the reference voltage V(REF) depends on the considered temperature and on radiation dose; however, it remains lower than 10% of the mean value of 1.5 V. The typical power dissipation at 2.5 V supply voltage is about 20 μW at room temperature and only 75 μW at a high temperature of 200 °C. To understand the effects caused by the combination of high total ionizing dose and temperature on such voltage reference, the threshold voltages of the used SOI MOSFETs were extracted under different conditions. The evolution of V(REF) and power consumption with temperature and radiation dose can then be explained in terms of the different balance between fixed oxide charge and interface states build-up. The total occupied area including pad-ring is less than 0.09 mm2.

  3. Interest of blood markers in predicting radiation-induced toxicity; Interet des marqueurs sanguins dans la prediction de la toxicite radio-induite

    Energy Technology Data Exchange (ETDEWEB)

    Lacombe, J. [Departement de cancerologie radiotherapie, CRLC Val-d' Aurelle-Paul-Lamarque, rue Croix-Verte, 34298 Montpellier cedex 5 (France); Universite de Montpellier I, 5, boulevard Henri-IV, CS 19044, 34967 Montpellier cedex 2 (France); Laboratoire d' oncoproteomique clinique, CRLC Val-d' Aurelle-Paul-Lamarque, rue Croix-Verte, 34298 Montpellier cedex 5 (France); Solassol, J. [Laboratoire de biologie cellulaire et hormonale, hopital Arnaud-de-Villeneuve, CHU de Montpellier, 371, avenue du Doyen-Gaston-Giraud, 34295 Montpellier cedex 5 (France); Laboratoire d' oncoproteomique clinique, CRLC Val-d' Aurelle-Paul-Lamarque, rue Croix-Verte, 34298 Montpellier cedex 5 (France); Coelho, M. [Inserm U896, institut de recherche en cancerologie de Montpellier, CRLC Val-d' Aurelle-Paul-Lamarque, rue Croix-Verte, 34298 Montpellier cedex 5 (France); Ozsahin, M. [Service de radio-oncologie, centre hospitalier universitaire Vaudois, 1011 Lausanne (Switzerland); Azria, D. [Departement de cancerologie radiotherapie, CRLC Val-d' Aurelle-Paul-Lamarque, rue Croix-Verte, 34298 Montpellier cedex 5 (France); Universite de Montpellier I, 5, boulevard Henri-IV, CS 19044, 34967 Montpellier cedex 2 (France); Inserm U896, institut de recherche en cancerologie de Montpellier, CRLC Val-d' Aurelle-Paul-Lamarque, rue Croix-Verte, 34298 Montpellier cedex 5 (France)

    2011-08-15

    The oncologic outcome and the total dose are highly correlated with the treatment by ionizing radiation. The dose increase (total or per fraction) may provoke late-side effects that are potentially irreversible. The radiation-induced CD8 lymphocyte apoptotic value and the molecular modifications within the lymphocyte are capable of predicting the level of risk of developing late-side effects after curative intent radiotherapy. In this review, we present the different blood assays in this setting and discuss the current possibilities of researches, namely those involving the proteomic process. (authors)

  4. TU-CD-BRB-01: Normal Lung CT Texture Features Improve Predictive Models for Radiation Pneumonitis

    International Nuclear Information System (INIS)

    Krafft, S; Briere, T; Court, L; Martel, M

    2015-01-01

    Purpose: Existing normal tissue complication probability (NTCP) models for radiation pneumonitis (RP) traditionally rely on dosimetric and clinical data but are limited in terms of performance and generalizability. Extraction of pre-treatment image features provides a potential new category of data that can improve NTCP models for RP. We consider quantitative measures of total lung CT intensity and texture in a framework for prediction of RP. Methods: Available clinical and dosimetric data was collected for 198 NSCLC patients treated with definitive radiotherapy. Intensity- and texture-based image features were extracted from the T50 phase of the 4D-CT acquired for treatment planning. A total of 3888 features (15 clinical, 175 dosimetric, and 3698 image features) were gathered and considered candidate predictors for modeling of RP grade≥3. A baseline logistic regression model with mean lung dose (MLD) was first considered. Additionally, a least absolute shrinkage and selection operator (LASSO) logistic regression was applied to the set of clinical and dosimetric features, and subsequently to the full set of clinical, dosimetric, and image features. Model performance was assessed by comparing area under the curve (AUC). Results: A simple logistic fit of MLD was an inadequate model of the data (AUC∼0.5). Including clinical and dosimetric parameters within the framework of the LASSO resulted in improved performance (AUC=0.648). Analysis of the full cohort of clinical, dosimetric, and image features provided further and significant improvement in model performance (AUC=0.727). Conclusions: To achieve significant gains in predictive modeling of RP, new categories of data should be considered in addition to clinical and dosimetric features. We have successfully incorporated CT image features into a framework for modeling RP and have demonstrated improved predictive performance. Validation and further investigation of CT image features in the context of RP NTCP

  5. Pretreatment clinical findings predict outcome for patients receiving preoperative radiation for rectal cancer

    International Nuclear Information System (INIS)

    Myerson, Robert J.; Singh, Anurag; Birnbaum, Elisa H.; Fry, Robert D.; Fleshman, James W.; Kodner, Ira J.; Lockett, Mary Ann; Picus, Joel; Walz, Bruce J.; Read, Thomas E.

    2001-01-01

    adverse clinical factors were present: 0 for none, 1 for one or two, 2 for three or four. This sorted outcome highly significantly (p≤0.002, Tarone Ware), with 5-year LC/FFR of 98%/85% (score 0), 90%/72% (score 1), and 74%/58% (score 2). The scoring system sorts the data for both subgroups of surgeons; however, there are substantial differences in LC on the basis of the surgeon's experience. For colorectal specialists (251 cases), the 5-year LC is 100%, 94%, and 78% for scores of 0, 1, and 2, respectively (p=0.004). For the more mixed group of nonspecialist surgeons (133 cases), LC is 98%, 80%, and 65% for scores of 0, 1, and 2 (p=0.008). In multivariate analysis, the clinical score and surgeon's background retained independent predictive value, even when pathologic stage was included. Conclusions: For many patients with rectal cancer, adjuvant treatment can be administered in a well-tolerated sequential fashion--moderate doses of preoperative radiation followed by surgery followed by postoperative chemotherapy to address the risk of occult metastatic disease. A clinical scoring system has been presented here that would suggest that the local control is excellent for lesions with a score of 0 or (if the surgeon is experienced) 1, and therefore sequential treatment could be considered. Cases with a clinical score of 2 should be strongly considered for protocols evaluating more aggressive preoperative treatment, such as combined modality preoperative treatment

  6. Development of fast and radiation hard Monolithic Active Pixel Sensors (MAPS) optimized for open charm meson detection with the CBM experiment

    International Nuclear Information System (INIS)

    Deveaux, M.

    2008-03-01

    The adequacy of CMOS MAPS (Monolithic Active Pixel Sensors) to provide high spatial resolution while submitted to high particle flux and radiation level is assessed in this work. A 55 Fe-source and minimum ionizing particle beams were used to study the performances of MAPS being irradiated either with neutrons and X-rays. As expected, ionizing radiation dominantly causes an increase of the leakage current of the pixels, which translates into increased shot noise. Non-ionizing radiation generates increases in terms of leakage currents but can reduce substantially the lifetime of the signal electrons in the pixel. The latter was found to cause a dramatic drop of the signal if the lifetime of the electrons shrinks below the time required for charge collection. The performances of irradiated detectors were studied as a function of the operation conditions, i.e. in terms of temperature and integration time of the pixel. It was demonstrated that running the detectors at low temperature ( 7 collisions per second, would shrink the lifetime of the detector to a few days. It was however demonstrated that a balanced configuration exists where, for lower beam interaction rate, enough D 0 -mesons can be collected and analyzed to investigate their production properties with a satisfactory sensitivity. (A.C.)

  7. A comparative study of the radiation hardness of plastic scintillators for the upgrade of the Tile Calorimeter of the ATLAS detector

    Science.gov (United States)

    Liao, S.; Erasmus, R.; Jivan, H.; Pelwan, C.; Peters, G.; Sideras-Haddad, E.

    2015-10-01

    The influence of radiation on the light transmittance of plastic scintillators was studied experimentally. The high optical transmittance property of plastic scintillators makes them essential in the effective functioning of the Tile calorimeter of the ATLAS detector at CERN. This significant role played by the scintillators makes this research imperative in the movement towards the upgrade of the tile calorimeter. The radiation damage of polyvinyl toluene (PVT) based plastic scintillators was studied, namely, EJ-200, EJ-208 and EJ-260, all manufactured and provided to us by ELJEN technology. In addition, in order to compare to scintillator brands actually in use at the ATLAS detector currently, two polystyrene (PS) based scintillators and an additional PVT based scintillator were also scrutinized in this study, namely, Dubna, Protvino and Bicron, respectively. All the samples were irradiated using a 6 MeV proton beam at different doses at iThemba LABS Gauteng. The radiation process was planned and mimicked by doing simulations using a SRIM program. In addition, transmission spectra for the irradiated and unirradiated samples of each grade were obtained, observed and analyzed.

  8. Incorporating Single-nucleotide Polymorphisms Into the Lyman Model to Improve Prediction of Radiation Pneumonitis

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Susan L., E-mail: sltucker@mdanderson.org [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li Minghuan [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Xu Ting; Gomez, Daniel [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Yuan Xianglin [Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Yu Jinming [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Liu Zhensheng; Yin Ming; Guan Xiaoxiang; Wang Lie; Wei Qingyi [Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Vinogradskiy, Yevgeniy [University of Colorado School of Medicine, Aurora, Colorado (United States); Martel, Mary [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-01-01

    Purpose: To determine whether single-nucleotide polymorphisms (SNPs) in genes associated with DNA repair, cell cycle, transforming growth factor-{beta}, tumor necrosis factor and receptor, folic acid metabolism, and angiogenesis can significantly improve the fit of the Lyman-Kutcher-Burman (LKB) normal-tissue complication probability (NTCP) model of radiation pneumonitis (RP) risk among patients with non-small cell lung cancer (NSCLC). Methods and Materials: Sixteen SNPs from 10 different genes (XRCC1, XRCC3, APEX1, MDM2, TGF{beta}, TNF{alpha}, TNFR, MTHFR, MTRR, and VEGF) were genotyped in 141 NSCLC patients treated with definitive radiation therapy, with or without chemotherapy. The LKB model was used to estimate the risk of severe (grade {>=}3) RP as a function of mean lung dose (MLD), with SNPs and patient smoking status incorporated into the model as dose-modifying factors. Multivariate analyses were performed by adding significant factors to the MLD model in a forward stepwise procedure, with significance assessed using the likelihood-ratio test. Bootstrap analyses were used to assess the reproducibility of results under variations in the data. Results: Five SNPs were selected for inclusion in the multivariate NTCP model based on MLD alone. SNPs associated with an increased risk of severe RP were in genes for TGF{beta}, VEGF, TNF{alpha}, XRCC1 and APEX1. With smoking status included in the multivariate model, the SNPs significantly associated with increased risk of RP were in genes for TGF{beta}, VEGF, and XRCC3. Bootstrap analyses selected a median of 4 SNPs per model fit, with the 6 genes listed above selected most often. Conclusions: This study provides evidence that SNPs can significantly improve the predictive ability of the Lyman MLD model. With a small number of SNPs, it was possible to distinguish cohorts with >50% risk vs <10% risk of RP when they were exposed to high MLDs.

  9. The Effect Of Gamma Radiation On The Shear Bond Strength And Micro-Hardness Of Zirconia Ceramic Using Three Types Of Luting Agents

    International Nuclear Information System (INIS)

    Abd El Rahman, R.H.M.

    2012-01-01

    Complete elimination of radiation exposure is impossible. All humans are continuously exposed to natural background ionizing radiation from cosmic rays; radioactive elements in the earth’s crust; potassium- 40, and other radionuclides normally present in human tissues; as well as inhaled radon and its daughter elements. In people residing at high altitudes, the contribution from cosmic rays may be increased two-folds. Likewise, in regions where the earth’s crust is rich in radium, the contribution from this radionuclide may be similarly increased. However, we know that if we are exposed to a lot of it, or even to a small amount over a long period of time it can cause many health problems. When ionizing radiation interacts with the human body, it gives its energy to the body tissues. The amount of energy absorbed per unit weight of the organ or tissue is called absorbed dose and is expressed in units of gray (Gy). One gray dose is equivalent to one joule radiation energy absorbed per kilogram of organ or tissue weight. Studies have reported on the physical and chemical changes in enamel after radiotherapy, which are a direct consequence of the irradiation treatment. For dentin, significant reduction in microhardness is observed after irradiation, and then accompanied by reduced stability of the amelodentinal junction after radiotherapy. The cementation of crown and bridge can be extremely demanding on both the patient and dentist. This is exacerbated by luting materials not holding up very well in the altered oral environment, due to the reduced stability of the dentoenamel junction after radiotherapy. Glass ionomer cements (GICs) are tooth-colored materials that have several clinical advantages over other restorative materials. These include physicochemical bonding to the tooth structures and long-term fluoride release. Due to the irreversibility of radiation-induced xerostomia, the re mineralization effects of saliva may not be expected in irradiated patients

  10. Combining Physical and Biologic Parameters to Predict Radiation-Induced Lung Toxicity in Patients With Non-Small-Cell Lung Cancer Treated With Definitive Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Stenmark, Matthew H. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Cai Xuwei [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Radiation Oncology, Shanghai Cancer Hospital, Fudan University, Shanghai (China); Shedden, Kerby [Department of Biostatistics, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Hayman, James A. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Yuan Shuanghu [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Radiation Oncology, Shangdong Cancer Hospital, Jinan (China); Ritter, Timothy [Veterans Affairs Medical Center, Ann Arbor, Michigan (United States); Ten Haken, Randall K.; Lawrence, Theodore S. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Kong Fengming, E-mail: fengkong@med.umich.edu [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Veterans Affairs Medical Center, Ann Arbor, Michigan (United States)

    2012-10-01

    Purpose: To investigate the plasma dynamics of 5 proinflammatory/fibrogenic cytokines, including interleukin-1beta (IL-1{beta}), IL-6, IL-8, tumor necrosis factor alpha (TNF-{alpha}), and transforming growth factor beta1 (TGF-{beta}1) to ascertain their value in predicting radiation-induced lung toxicity (RILT), both individually and in combination with physical dosimetric parameters. Methods and Materials: Treatments of patients receiving definitive conventionally fractionated radiation therapy (RT) on clinical trial for inoperable stages I-III lung cancer were prospectively evaluated. Circulating cytokine levels were measured prior to and at weeks 2 and 4 during RT. The primary endpoint was symptomatic RILT, defined as grade 2 and higher radiation pneumonitis or symptomatic pulmonary fibrosis. Minimum follow-up was 18 months. Results: Of 58 eligible patients, 10 (17.2%) patients developed RILT. Lower pretreatment IL-8 levels were significantly correlated with development of RILT, while radiation-induced elevations of TGF-ss1 were weakly correlated with RILT. Significant correlations were not found for any of the remaining 3 cytokines or for any clinical or dosimetric parameters. Using receiver operator characteristic curves for predictive risk assessment modeling, we found both individual cytokines and dosimetric parameters were poor independent predictors of RILT. However, combining IL-8, TGF-ss1, and mean lung dose into a single model yielded an improved predictive ability (P<.001) compared to either variable alone. Conclusions: Combining inflammatory cytokines with physical dosimetric factors may provide a more accurate model for RILT prediction. Future study with a larger number of cases and events is needed to validate such findings.

  11. Pitfalls in Prediction Modeling for Normal Tissue Toxicity in Radiation Therapy: An Illustration With the Individual Radiation Sensitivity and Mammary Carcinoma Risk Factor Investigation Cohorts

    Energy Technology Data Exchange (ETDEWEB)

    Mbah, Chamberlain, E-mail: chamberlain.mbah@ugent.be [Department of Basic Medical Sciences, Faculty of Health Sciences, Ghent University, Ghent (Belgium); Department of Mathematical Modeling, Statistics, and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, Ghent (Belgium); Thierens, Hubert [Department of Basic Medical Sciences, Faculty of Health Sciences, Ghent University, Ghent (Belgium); Thas, Olivier [Department of Mathematical Modeling, Statistics, and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, Ghent (Belgium); National Institute for Applied Statistics Research Australia, University of Wollongong, Wollongong, New South Wales (Australia); De Neve, Jan [Department of Data Analysis, Faculty of Psychology and Educational Sciences, Ghent University, Ghent (Belgium); Chang-Claude, Jenny; Seibold, Petra; Botma, Akke [Division of Cancer Epidemiology, German Cancer Research Center, Heidelberg (Germany); West, Catharine [Translational Radiobiology Group, Institute of Cancer Sciences, Radiotherapy Related Research, Christie Hospital NHS Trust, University of Manchester, Manchester (United Kingdom); De Ruyck, Kim [Department of Basic Medical Sciences, Faculty of Health Sciences, Ghent University, Ghent (Belgium)

    2016-08-01

    Purpose: To identify the main causes underlying the failure of prediction models for radiation therapy toxicity to replicate. Methods and Materials: Data were used from two German cohorts, Individual Radiation Sensitivity (ISE) (n=418) and Mammary Carcinoma Risk Factor Investigation (MARIE) (n=409), of breast cancer patients with similar characteristics and radiation therapy treatments. The toxicity endpoint chosen was telangiectasia. The LASSO (least absolute shrinkage and selection operator) logistic regression method was used to build a predictive model for a dichotomized endpoint (Radiation Therapy Oncology Group/European Organization for the Research and Treatment of Cancer score 0, 1, or ≥2). Internal areas under the receiver operating characteristic curve (inAUCs) were calculated by a naïve approach whereby the training data (ISE) were also used for calculating the AUC. Cross-validation was also applied to calculate the AUC within the same cohort, a second type of inAUC. Internal AUCs from cross-validation were calculated within ISE and MARIE separately. Models trained on one dataset (ISE) were applied to a test dataset (MARIE) and AUCs calculated (exAUCs). Results: Internal AUCs from the naïve approach were generally larger than inAUCs from cross-validation owing to overfitting the training data. Internal AUCs from cross-validation were also generally larger than the exAUCs, reflecting heterogeneity in the predictors between cohorts. The best models with largest inAUCs from cross-validation within both cohorts had a number of common predictors: hypertension, normalized total boost, and presence of estrogen receptors. Surprisingly, the effect (coefficient in the prediction model) of hypertension on telangiectasia incidence was positive in ISE and negative in MARIE. Other predictors were also not common between the 2 cohorts, illustrating that overcoming overfitting does not solve the problem of replication failure of prediction models completely

  12. Factors Predictive of Symptomatic Radiation Injury After Linear Accelerator-Based Stereotactic Radiosurgery for Intracerebral Arteriovenous Malformations

    Energy Technology Data Exchange (ETDEWEB)

    Herbert, Christopher, E-mail: cherbert@bccancer.bc.ca [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Moiseenko, Vitali [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); McKenzie, Michael [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Redekop, Gary [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Hsu, Fred [Department of Radiation Oncology, British Columbia Cancer Agency, Abbotsford, BC (Canada); Gete, Ermias; Gill, Brad; Lee, Richard; Luchka, Kurt [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); Haw, Charles [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Lee, Andrew [Department of Neurosurgery, Royal Columbian Hospital, New Westminster, BC (Canada); Toyota, Brian [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Martin, Montgomery [Department of Medical Imaging, British Columbia Cancer Agency, Vancouver, BC (Canada)

    2012-07-01

    Purpose: To investigate predictive factors in the development of symptomatic radiation injury after treatment with linear accelerator-based stereotactic radiosurgery for intracerebral arteriovenous malformations and relate the findings to the conclusions drawn by Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC). Methods and Materials: Archived plans for 73 patients who were treated at the British Columbia Cancer Agency were studied. Actuarial estimates of freedom from radiation injury were calculated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used for analysis of incidence of radiation injury. Log-rank test was used to search for dosimetric parameters associated with freedom from radiation injury. Results: Symptomatic radiation injury was exhibited by 14 of 73 patients (19.2%). Actuarial rate of symptomatic radiation injury was 23.0% at 4 years. Most patients (78.5%) had mild to moderate deficits according to Common Terminology Criteria for Adverse Events, version 4.0. On univariate analysis, lesion volume and diameter, dose to isocenter, and a V{sub x} for doses {>=}8 Gy showed statistical significance. Only lesion diameter showed statistical significance (p < 0.05) in a multivariate model. According to the log-rank test, AVM volumes >5 cm{sup 3} and diameters >30 mm were significantly associated with the risk of radiation injury (p < 0.01). The V{sub 12} also showed strong association with the incidence of radiation injury. Actuarial incidence of radiation injury was 16.8% if V{sub 12} was <28 cm{sup 3} and 53.2% if >28 cm{sup 3} (log-rank test, p = 0.001). Conclusions: This study confirms that the risk of developing symptomatic radiation injury after radiosurgery is related to lesion diameter and volume and irradiated volume. Results suggest a higher tolerance than proposed by QUANTEC. The widely differing findings reported in the literature, however, raise considerable uncertainties.

  13. Factors Predictive of Symptomatic Radiation Injury After Linear Accelerator-Based Stereotactic Radiosurgery for Intracerebral Arteriovenous Malformations

    International Nuclear Information System (INIS)

    Herbert, Christopher; Moiseenko, Vitali; McKenzie, Michael; Redekop, Gary; Hsu, Fred; Gete, Ermias; Gill, Brad; Lee, Richard; Luchka, Kurt; Haw, Charles; Lee, Andrew; Toyota, Brian; Martin, Montgomery

    2012-01-01

    Purpose: To investigate predictive factors in the development of symptomatic radiation injury after treatment with linear accelerator–based stereotactic radiosurgery for intracerebral arteriovenous malformations and relate the findings to the conclusions drawn by Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC). Methods and Materials: Archived plans for 73 patients who were treated at the British Columbia Cancer Agency were studied. Actuarial estimates of freedom from radiation injury were calculated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used for analysis of incidence of radiation injury. Log–rank test was used to search for dosimetric parameters associated with freedom from radiation injury. Results: Symptomatic radiation injury was exhibited by 14 of 73 patients (19.2%). Actuarial rate of symptomatic radiation injury was 23.0% at 4 years. Most patients (78.5%) had mild to moderate deficits according to Common Terminology Criteria for Adverse Events, version 4.0. On univariate analysis, lesion volume and diameter, dose to isocenter, and a V x for doses ≥8 Gy showed statistical significance. Only lesion diameter showed statistical significance (p 5 cm 3 and diameters >30 mm were significantly associated with the risk of radiation injury (p 12 also showed strong association with the incidence of radiation injury. Actuarial incidence of radiation injury was 16.8% if V 12 was 3 and 53.2% if >28 cm 3 (log–rank test, p = 0.001). Conclusions: This study confirms that the risk of developing symptomatic radiation injury after radiosurgery is related to lesion diameter and volume and irradiated volume. Results suggest a higher tolerance than proposed by QUANTEC. The widely differing findings reported in the literature, however, raise considerable uncertainties.

  14. Predicting Radiative Heat Transfer in Oxy-Methane Flame Simulations: An Examination of Its Sensitivities to Chemistry and Radiative Property Models

    Directory of Open Access Journals (Sweden)

    Hassan Abdul-Sater

    2015-01-01

    Full Text Available Measurements from confined, laminar oxy-methane flames at different O2/CO2 dilution ratios in the oxidizer are first reported with measurements from methane-air flames included for comparison. Simulations of these flames employing appropriate chemistry and radiative property modeling options were performed to garner insights into the experimental trends and assess prediction sensitivities to the choice of modeling options. The chemistry was modeled employing a mixture-fraction based approach, Eddy dissipation concept (EDC, and refined global finite rate (FR models. Radiative properties were estimated employing four weighted-sum-of-gray-gases (WSGG models formulated from different spectroscopic/model databases. The mixture fraction and EDC models correctly predicted the trends in flame length and OH concentration variations, and the O2, CO2, and temperature measurements outside the flames. The refined FR chemistry model predictions of CO2 and O2 deviated from their measured values in the flame with 50% O2 in the oxidizer. Flame radiant power estimates varied by less than 10% between the mixture fraction and EDC models but more than 60% between the different WSGG models. The largest variations were attributed to the postcombustion gases in the temperature range 500 K–800 K in the upper sections of the furnace which also contributed significantly to the overall radiative transfer.

  15. Individual response to ionising radiation: What predictive assay(s) to choose?; Reponse individuelle aux radiations ionisantes: quel(s) test(s) predictif(s) choisir?

    Energy Technology Data Exchange (ETDEWEB)

    Granzotto, A.; Viau, M.; Devic, C.; Maalouf, M.; Thomas, Ch.; Vogin, G.; Foray, N. [Inserm, U836, groupe de radiobiologie, institut des neurosciences, chemin Fortune-Ferrini, 38042 Grenoble (France); Granzotto, A.; Vogin, G.; Balosso, J. [Centre de hadrontherapie Etoile, 69008 Lyon (France); Joubert, A. [Societe Magelis, 84160 Cadenet (France); Maalouf, M. [Centre national d' etudes spatiales, 75001 Paris (France); Vogin, G.; Colin, C. [EA 3738, faculte de medecine, Lyon-Sud, 69921 Oullins (France); Malek, K.; Balosso, J. [Service de radiotherapie, CHU A.-Michallon, 38042 Grenoble (France); Colin, C. [Service de radiologie, CHU Lyon-Sud, 69490 Pierre-Benite (France)

    2011-02-15

    Individual response to ionizing radiation is an important information required to apply an efficient radiotherapy treatment against tumour and to avoid any adverse effects in normal tissues. In 1981, Fertil and Malaise have demonstrated that the post-irradiation local tumor control determined in vivo is correlated with clonogenic cell survival assessed in vitro. Furthermore, these authors have reminded the relevance of the concept of intrinsic radiosensitivity that is specific to each individual organ (Fertil and Malaise, 1981) [1]. To date, since clonogenicity assays are too time-consuming and do not provide any other molecular information, a plethora of research groups have attempted to determine the molecular bases of intrinsic radiosensitivity in order to propose reliable and faster predictive assays. To this aim, several approaches have been developed. Notably, the recent revolution in genomic and proteomics technologies is providing a considerable number of data but their link with radiosensitivity still remains to be elucidated. On another hand, the systematic screening of some candidate genes potentially involved in the radiation response is highlighting the complexity of the molecular and cellular mechanisms of DNA damage sensing and signalling and shows that an abnormal radiation response is not necessarily due to the impairment of one single protein. Finally, more modest approaches consisting in focusing some specific functions of DNA repair seem to provide more reliable clues to predict over-acute reactions caused by radiotherapy. In this review, we endeavored to analyse the contributions of these major approaches to predict human radiosensitivity. (authors)

  16. HeartCare+: A Smart Heart Care Mobile Application for Framingham-Based Early Risk Prediction of Hard Coronary Heart Diseases in Middle East

    Directory of Open Access Journals (Sweden)

    Hoda Ahmed Galal Elsayed

    2017-01-01

    Full Text Available Background. Healthcare is a challenging, yet so demanding sector that developing countries are paying more attention to recently. Statistics show that rural areas are expected to develop a high rate of heart diseases, which is a leading cause of sudden mortality, in the future. Thus, providing solutions that can assist rural people in detecting the cardiac risks early will be vital for uncovering and even preventing the long-term complications of cardiac diseases. Methodology. Mobile technology can be effectively utilized to limit the cardiac diseases’ prevalence in rural Middle East. This paper proposes a smart mobile solution for early risk detection of hard coronary heart diseases that uses the Framingham scoring model. Results. Smart HeartCare+ mobile app estimates accurately coronary heart diseases’ risk over 10 years based on clinical and nonclinical data and classifies the patient risk to low, moderate, or high. HeartCare+ also directs the patients to further treatment recommendations. Conclusion. This work attempts to investigate the effectiveness of the mobile technology in the early risk detection of coronary heart diseases. HeartCare+ app intensifies the communication channel between the lab workers and patients residing in rural areas and cardiologists and specialist residing in urban places.

  17. On the application of response surface methodology for predicting and optimizing surface roughness and cutting forces in hard turning by PVD coated insert

    Directory of Open Access Journals (Sweden)

    Hessainia Zahia

    2015-04-01

    Full Text Available This paper focuses on the exploitation of the response surface methodology (RSM to determine optimum cutting conditions leading to minimum surface roughness and cutting force components. The technique of RSM helps to create an efficient statistical model for studying the evolution of surface roughness and cutting forces according to cutting parameters: cutting speed, feed rate and depth of cut. For this purpose, turning tests of hardened steel alloy (AISI 4140 (56 HRC were carried out using PVD – coated ceramic insert under different cutting conditions. The equations of surface roughness and cutting forces were achieved by using the experimental data and the technique of the analysis of variance (ANOVA. The obtained results are presented in terms of mean values and confidence levels. It is shown that feed rate and depth of cut are the most influential factors on surface roughness and cutting forces, respectively. In addition, it is underlined that the surface roughness is mainly related to the cutting speed, whereas depth of cut has the greatest effect on the evolution of cutting forces. The optimal machining parameters obtained in this study represent reductions about 6.88%, 3.65%, 19.05% in cutting force components (Fa, Fr, Ft, respectively. The latters are compared with the results of initial cutting parameters for machining AISI 4140 steel in the hard turning process.

  18. Importance of ECP in the prediction of radiation fields in PWR and VVER primary circuits

    International Nuclear Information System (INIS)

    Urquidi-Macdonald, M.; Jacesko, S.L.; Macdonald, Digby D.; Salter-Williams, M.

    2002-01-01

    A model has been developed for predicting mass and activity transport in the primary coolant circuits of PWRs and VVERs with the objective of demonstrating and quantifying the importance of the electrochemical corrosion potential (ECP) in determining the impact of both processes on reactor operation. The model initially employs a radiolysis/mixed potential code to calculate the ECP at four locations (core, hot leg, steam generator, cold leg) and the ECP is then used to estimate the local magnetite solubility. The solubility is then averaged around the loop to yield the ''background'' solubility. Comparison of the background solubility with the local solubility determines whether precipitation or dissolution will occur at any given point in the circuit under any given set of conditions. It is further assumed that the concentration of 59 Co in the coolant is given by the isotopic fraction of this species compared with iron averaged over all materials and weighted by the respective wetted areas. Activation of 59 Co to 60 Co is assumed to occur in the coolant phase by fast, epithermal, and thermal neutron capture. The calculated activity is then used to train an artificial neural network (ANN) to establish relationships between activity at any given location and the operating properties of the reactor, including coolant pH, ECP, temperature, power level, etc. The model predicts that during shut down, magnetite (and hence 59 Co) migrates to the core, where it is irradiated and activated, particularly during subsequent start-up. During start-up, the magnetite (and hence 60 Co) migrates from the core to out-of-core surfaces where it establishes the radiation fields. (authors)

  19. Apparent diffusion coefficient histogram analysis can evaluate radiation-induced parotid damage and predict late xerostomia degree in nasopharyngeal carcinoma.

    Science.gov (United States)

    Zhou, Nan; Guo, Tingting; Zheng, Huanhuan; Pan, Xia; Chu, Chen; Dou, Xin; Li, Ming; Liu, Song; Zhu, Lijing; Liu, Baorui; Chen, Weibo; He, Jian; Yan, Jing; Zhou, Zhengyang; Yang, Xiaofeng

    2017-09-19

    We investigated apparent diffusion coefficient (ADC) histogram analysis to evaluate radiation-induced parotid damage and predict xerostomia degrees in nasopharyngeal carcinoma (NPC) patients receiving radiotherapy. The imaging of bilateral parotid glands in NPC patients was conducted 2 weeks before radiotherapy (time point 1), one month after radiotherapy (time point 2), and four months after radiotherapy (time point 3). From time point 1 to 2, parotid volume, skewness, and kurtosis decreased ( P histogram parameters increased (all P histogram parameters. Early mean change rates for bilateral parotid SD and ADC max could predict late xerostomia degrees at seven months after radiotherapy (three months after time point 3) with AUC of 0.781 and 0.818 ( P = 0.014, 0.005, respectively). ADC histogram parameters were reproducible (intraclass correlation coefficient, 0.830 - 0.999). ADC histogram analysis could be used to evaluate radiation-induced parotid damage noninvasively, and predict late xerostomia degrees of NPC patients treated with radiotherapy.

  20. Prediction of Daily Global Solar Radiation by Daily Temperatures and Artificial Neural Networks in Different Climates

    Directory of Open Access Journals (Sweden)

    S. I Saedi

    2018-03-01

    Full Text Available Introduction Global solar radiation is the sum of direct, diffuse, and reflected solar radiation. Weather forecasts, agricultural practices, and solar equipment development are three major fields that need proper information about solar radiation. Furthermore, sun in regarded as a huge source of renewable and clean energy which can be used in numerous applications to get rid of environmental impacts of non-renewable fossil fuels. Therefore, easy and fast estimation of daily global solar radiation would play an effective role is these affairs. Materials and Methods This study aimed at predicting the daily global solar radiation by means of artificial neural network (ANN method, based on easy-to-gain weather data i.e. daily mean, minimum and maximum temperatures. Having a variety of climates with long-term valid weather data, Washington State, located at the northwestern part of USA was chosen for this purpose. It has a total number of 19 weather stations to cover all the State climates. First, a station with the largest number of valid historical weather data (Lind was chosen to develop, validate, and test different ANN models. Three training algorithms i.e. Levenberg – Marquardt (LM, Scaled Conjugate Gradient (SCG, and Bayesian regularization (BR were tested in one and two hidden layer networks each with up to 20 neurons to derive six best architectures. R, RMSE, MAPE, and scatter plots were considered to evaluate each network in all steps. In order to investigate the generalizability of the best six models, they were tested in other Washington State weather stations. The most accurate and general models was evaluated in an Iran sample weather station which was chosen to be Mashhad. Results and Discussion The variation of MSE for the three training functions in one hidden layer models for Lind station indicated that SCG converged weights and biases in shorter time than LM, and LM did that faster than BR. It means that SCG provided the fastest

  1. Individualized Prediction of Overall Survival After Postoperative Radiation Therapy in Patients With Early-Stage Cervical Cancer: A Korean Radiation Oncology Group Study (KROG 13-03)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Jin [Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Han, Seungbong [Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Kim, Young Seok, E-mail: ysk@amc.seoul.kr [Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Nam, Joo-Hyun [Department of Obstetrics and Gynecology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Kim, Hak Jae [Department of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Jae Weon [Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul (Korea, Republic of); Park, Won [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Byoung-Gie [Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Jin Hee [Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of); Cha, Soon Do [Department of Obstetrics and Gynecology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of); Kim, Juree [Department of Radiation Oncology, Cheil General Hospital and Women' s Healthcare Center, Kwandong University, College of Medicine, Seoul (Korea, Republic of); Lee, Ki-Heon [Department of Obstetrics and Gynecology, Cheil General Hospital and Women' s Healthcare Center, Kwandong University, College of Medicine, Seoul (Korea, Republic of); Yoon, Mee Sun [Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Jeollanam-do (Korea, Republic of); and others

    2013-11-15

    Purpose: A nomogram is a predictive statistical model that generates the continuous probability of a clinical event such as death or recurrence. The aim of the study was to construct a nomogram to predict 5-year overall survival after postoperative radiation therapy for stage IB to IIA cervical cancer. Methods and Materials: The clinical data from 1702 patients with early-stage cervical cancer, treated at 10 participating hospitals from 1990 to 2011, were reviewed to develop a prediction nomogram based on the Cox proportional hazards model. Demographic, clinical, and pathologic variables were included and analyzed to formulate the nomogram. The discrimination and calibration power of the model was measured using a concordance index (c-index) and calibration curve. Results: The median follow-up period for surviving patients was 75.6 months, and the 5-year overall survival probability was 87.1%. The final model was constructed using the following variables: age, number of positive pelvic lymph nodes, parametrial invasion, lymphovascular invasion, and the use of concurrent chemotherapy. The nomogram predicted the 5-year overall survival with a c-index of 0.69, which was superior to the predictive power of the International Federation of Gynecology and Obstetrics (FIGO) staging system (c-index of 0.54). Conclusions: A survival-predicting nomogram that offers an accurate level of prediction and discrimination was developed based on a large multi-center study. The model may be more useful than the FIGO staging system for counseling individual patients regarding prognosis.

  2. Individualized Prediction of Overall Survival After Postoperative Radiation Therapy in Patients With Early-Stage Cervical Cancer: A Korean Radiation Oncology Group Study (KROG 13-03)

    International Nuclear Information System (INIS)

    Lee, Hyun Jin; Han, Seungbong; Kim, Young Seok; Nam, Joo-Hyun; Kim, Hak Jae; Kim, Jae Weon; Park, Won; Kim, Byoung-Gie; Kim, Jin Hee; Cha, Soon Do; Kim, Juree; Lee, Ki-Heon; Yoon, Mee Sun

    2013-01-01

    Purpose: A nomogram is a predictive statistical model that generates the continuous probability of a clinical event such as death or recurrence. The aim of the study was to construct a nomogram to predict 5-year overall survival after postoperative radiation therapy for stage IB to IIA cervical cancer. Methods and Materials: The clinical data from 1702 patients with early-stage cervical cancer, treated at 10 participating hospitals from 1990 to 2011, were reviewed to develop a prediction nomogram based on the Cox proportional hazards model. Demographic, clinical, and pathologic variables were included and analyzed to formulate the nomogram. The discrimination and calibration power of the model was measured using a concordance index (c-index) and calibration curve. Results: The median follow-up period for surviving patients was 75.6 months, and the 5-year overall survival probability was 87.1%. The final model was constructed using the following variables: age, number of positive pelvic lymph nodes, parametrial invasion, lymphovascular invasion, and the use of concurrent chemotherapy. The nomogram predicted the 5-year overall survival with a c-index of 0.69, which was superior to the predictive power of the International Federation of Gynecology and Obstetrics (FIGO) staging system (c-index of 0.54). Conclusions: A survival-predicting nomogram that offers an accurate level of prediction and discrimination was developed based on a large multi-center study. The model may be more useful than the FIGO staging system for counseling individual patients regarding prognosis

  3. Predictive spatio-temporal model for spatially sparse global solar radiation data

    International Nuclear Information System (INIS)

    André, Maïna; Dabo-Niang, Sophie; Soubdhan, Ted; Ould-Baba, Hanany

    2016-01-01

    This paper introduces a new approach for the forecasting of solar radiation series at a located station for very short time scale. We built a multivariate model in using few stations (3 stations) separated with irregular distances from 26 km to 56 km. The proposed model is a spatio temporal vector autoregressive VAR model specifically designed for the analysis of spatially sparse spatio-temporal data. This model differs from classic linear models in using spatial and temporal parameters where the available predictors are the lagged values at each station. A spatial structure of stations is defined by the sequential introduction of predictors in the model. Moreover, an iterative strategy in the process of our model will select the necessary stations removing the uninteresting predictors and also selecting the optimal p-order. We studied the performance of this model. The metric error, the relative root mean squared error (rRMSE), is presented at different short time scales. Moreover, we compared the results of our model to simple and well known persistence model and those found in literature. - Highlights: • A spatio-temporal VAR forecast model is used for spatially sparse data solar. • Lags and locations are selected by an optimization strategy. • Definition of spatial ordering of predictors influences forecasting results. • The model shows a better performance predictive at 30 min ahead in our context. • Benchmarking study shows a more accurate forecast at 1 h ahead with spatio-temporal VAR.