WorldWideScience

Sample records for activation detectors

  1. Passive neutron dosemeter with activation detector

    Valero L, C.; Banuelos F, A.; Guzman G, K. A.; Borja H, C. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2011-10-15

    A passive neutron dosemeter with {sup 197}Au activation detector has been developed. The area dosemeter was made as a 20.5 {phi} x 20.5 cm{sup 2} polyethylene moderator, with a polyethylene pug where a {sup 197}Au foil can be located either parallel or perpendicular to moderator axis. Using Monte Carlo methods, with the MCNP5 code. With the fluence response and the fluence-to-equivalent dose conversion coefficients from ICRP-74, responses to H*(10) were also calculated, these were compared against responses of commercially available neutron area monitors and dosemeters. (Author)

  2. Dual energy radiography using active detector technology

    A new technology has been implemented using an open-quotes active-detectorclose quotes comprised of two computed radiography (CR) imaging plates in a sandwich geometry for dual-energy radiography. This detector allows excellent energy separation, short exposure time, and high signal to noise ratio (SNR) for clinically robust open-quotes bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images with minimum patient motion. Energy separation is achieved by two separate exposures at widely different kVp's: the high energy (120 kVp + 1.5 mm Cu filter) exposure is initiated first, followed by a short burst of intense light to erase the latent image on the front plate, and then a 50 kVp (low energy) exposure. A personal computer interfaced to the x-ray generator, filter wheel, and active detector system orchestrates the acquisition sequence within a time period of 150 msec. The front and back plates are processed using a CR readout algorithm with fixed speed and wide dynamic range. open-quotes Bone-onlyclose quotes and open-quotes soft-tissue onlyclose quotes images are calculated by geometric alignment of the two images and application of dual energy decomposition algorithms on a pixel by pixel basis. Resultant images of a calibration phantom demonstrate an increase of SNR2 / dose by ∼73 times when compared to a single exposure open-quotes passive-detectorclose quotes comprised of CR imaging plates, and an ∼8 fold increase compared to a screen-film dual-energy cassette comprised of different phosphor compounds. In conclusion, dual energy imaging with open-quotes active detectorclose quotes technology is clinically feasible and can provide substantial improvements over conventional methods for dual-energy radiography

  3. Synthesis and evaluation of phase detectors for active bit synchronizers

    Mcbride, A. L.

    1974-01-01

    Self-synchronizing digital data communication systems usually use active or phase-locked loop (PLL) bit synchronizers. The three main elements of PLL synchronizers are the phase detector, loop filter, and the voltage controlled oscillator. Of these three elements, phase detector synthesis is the main source of difficulty, particularly when the received signals are demodulated square-wave signals. A phase detector synthesis technique is reviewed that provides a physically realizable design for bit synchronizer phase detectors. The development is based upon nonlinear recursive estimation methods. The phase detector portion of the algorithm is isolated and analyzed.

  4. Charged particle detectors with active detector surface for partial energy deposition of the charged particles and related methods

    Gerts, David W; Bean, Robert S; Metcalf, Richard R

    2013-02-19

    A radiation detector is disclosed. The radiation detector comprises an active detector surface configured to generate charge carriers in response to charged particles associated with incident radiation. The active detector surface is further configured with a sufficient thickness for a partial energy deposition of the charged particles to occur and permit the charged particles to pass through the active detector surface. The radiation detector further comprises a plurality of voltage leads coupled to the active detector surface. The plurality of voltage leads is configured to couple to a voltage source to generate a voltage drop across the active detector surface and to separate the charge carriers into a plurality of electrons and holes for detection. The active detector surface may comprise one or more graphene layers. Timing data between active detector surfaces may be used to determine energy of the incident radiation. Other apparatuses and methods are disclosed herein.

  5. Recovery of thallium-activated sodium iodide detectors

    A method for recovery and treatment of sodium iodide thallium activated detectors, NaI(Tl), is described. Special techniques of polishing and mounting in a dry environment (relative humidity less than 10%) are applied. The resolution was determined and compared with that obtained with a new detector and the results showed that a typical 3' phi x 3' recovered detector had a performance very similar to that of a new one. (Author)

  6. Active volume studies with depleted and enriched BEGe detectors

    Sturm, Katharina von [Eberhard Karls Universitaet Tuebingen (Germany); Universita degli Studi di Padova, Padua (Italy); Collaboration: GERDA-Collaboration

    2013-07-01

    The Gerda experiment is currently taking data for the search of the 0νββ decay in {sup 76}Ge. In 2013, 30 newly manufactured Broad Energy Germanium (BEGe) diodes will be deployed which will double the active mass within Gerda. These detectors were fabricated from high-purity germanium enriched in {sup 76}Ge and tested in the HADES underground laboratory, owned by SCK.CEN, in Mol, Belgium. As the BEGes are source and detector at the same time, one crucial parameter is their active volume which directly enters into the evaluation of the half-life. This talk illustrates the dead layer and active volume determination of prototype detectors from depleted germanium as well as the newly produced detectors from enriched material, using gamma spectroscopy methods and comparing experimental results to Monte-Carlo simulations. Recent measurements and their results are presented, and systematic effects are discussed.

  7. CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors

    Turchetta, R

    2006-01-01

    This paper reviews the development of CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors. MAPS are developed in a standard CMOS technology. In the imaging field, where the technology found its first applications, they are also known as CMOS Image Sensors. The use of MAPS as a detector for particle physics was first proposed at the end of 1999. Since then, their good performance in terms of spatial resolution, efficiency, radiation hardness have been demonstrated and work is now well under way to deliver the first MAPS-based vertex detectors.

  8. Calibration of HPGe detector for flowing sample neutron activation analysis

    This work is concerned with the calibration of the HPGe detector used in flowing sample neutron activation analysis technique. The optimum counting configuration and half-life based correction factors have been estimated using Monte Carlo computer simulations. Depending on detection efficiency, sample volume and flow type around the detector, the optimum geometry was achieved using 4 mm diameter hose rolled in spiral shape around the detector. The derived results showed that the half-life based efficiency correction factors are strongly dependent on sample flow rate and the isotope half-life. (author)

  9. CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors

    This paper reviews the development of CMOS Monolithic Active Pixel Sensors (MAPS) for future vertex detectors. MAPS are developed in a standard CMOS technology. In the imaging field, where the technology found its first applications, they are also known as CMOS Image Sensors. The use of MAPS as a detector for particle physics was first proposed at the end of 1999. Since then, their good performance in terms of spatial resolution, efficiency, radiation hardness have been demonstrated and work is now well under way to deliver the first MAPS-based vertex detectors

  10. Active Well Counting Using New PSD Plastic Detectors

    Hausladen, Paul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Newby, Jason [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McElroy, Robert Dennis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-11-01

    This report presents results and analysis from a series of proof-of-concept measurements to assess the suitability of segmented detectors constructed from Eljen EJ-299-34 PSD-plastic scintillator with pulse-shape discrimination capability for the purposes of quantifying uranium via active neutron coincidence counting. Present quantification of bulk uranium materials for international safeguards and domestic materials control and accounting relies on active neutron coincidence counting systems, such as the Active Well Coincidence Counter (AWCC) and the Uranium Neutron Coincidence Collar (UNCL), that use moderated He-3 proportional counters along with necessarily low-intensity 241Am(Li) neutron sources. Scintillation-based fast-neutron detectors are a potentially superior technology to the existing AWCC and UNCL designs due to their spectroscopic capability and their inherently short neutron coincidence times that largely eliminate random coincidences and enable interrogation by stronger sources. One of the past impediments to the investigation and adoption of scintillation counters for the purpose of quantifying bulk uranium was the commercial availability of scintillators having the necessary neutron-gamma pulse-shape discrimination properties only as flammable liquids. Recently, Eljen EJ-299-34 PSD-plastic scintillator became commercially available. The present work is the first assessment of an array of PSD-plastic detectors for the purposes of quantifying bulk uranium. The detector panel used in the present work was originally built as the focal plane for a fast-neutron imager, but it was repurposed for the present investigation by construction of a stand to support the inner well of an AWCC immediately in front of the detector panel. The detector panel and data acquisition of this system are particularly well suited for performing active-well fast-neutron counting of LEU and HEU samples because the active detector volume is solid, the 241Am(Li) interrogating

  11. Indoor 222Rn measurements using an activated charcoal detector

    A commercially available activated charcoal detector for measuring 222Rn activity concentrations in air was calibrated with known amounts of 222Rn and examined in terms of air luminescence counts and interferences from 220Rn and 219Rn. The results for conditions normally encountered indoor indicate that the detector is simple and reliable. The method has been applied to assay indoor 222Rn activity concentrations in 387 homes in Tokyo and the adjacent four prefectures, which ranged from 0.7 to 140 Bq/m3 and averaged 22.7 Bq/m3

  12. In-core detector activation rate for a PWR assembly

    The in-core detector system is the principal source of information for determining relative assembly powers, and maximum fuel rod powers in a reactor core. The detector signals are used in conjunction with pre-calculated factors, and appropriate normalizations, to obtain measured power values. Considerable reliance is placed on the accuracy of in-core detector inferred power distributions in reactor operations, and in the verification of calculational methods. The objective of this study was to compare results from standard design codes for the in-core detector activation rate (and the fission rate distribution in an assembly), to results obtained from a detailed calculation performed with a continuous energy Monte Carlo program with ENDF/B-V nuclear data

  13. Monolithic active pixel radiation detector with shielding techniques

    Deptuch, Grzegorz W.

    2016-09-06

    A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

  14. Optical theorem detectors for active scatterers

    Marengo, Edwin A.; Tu, Jing

    2015-10-01

    We develop a new theory of the optical theorem for scalar fields in nonhomogeneous media which can be bounded or unbounded. It applies to arbitrary lossless backgrounds and quite general probing fields. The derived formulation holds for arbitrary passive scatterers, which can be dissipative, as well as for the more general class of active scatterers which are composed of a (passive) scatterer component and an active, radiating (antenna) component. The generalization of the optical theorem to active scatterers is relevant to many applications such as surveillance of active targets including certain cloaks and invisible scatterers and wireless communications. The derived theoretical framework includes the familiar real power optical theorem describing power extinction due to both dissipation and scattering as well as a novel reactive optical theorem related to the reactive power changes. The developed approach naturally leads to three optical theorem indicators or statistics which can be used to detect changes or targets in unknown complex media. The paper includes numerical simulation results that illustrate the application of the derived optical theorem results to change detection in complex and random media.

  15. NaI detector neutron activation spectra for PGNAA applications

    Gardner; El; Zheng; Hayden; Mayo

    2000-10-01

    When NaI detectors are used in prompt gamma-ray neutron activation analysis devices, they are activated by neutrons that penetrate the detector. While thermal neutron filters like boron or lithium can be used to reduce this activation, it can never be completely eliminated by this approach since high energy neutrons can penetrate the detector and thermalize inside it. This activation results in the emission of prompt gamma rays from both the I and Na and the production of the radioisotopes 128I and 24Na that subsequently decay and emit their characteristic beta particles and gamma rays. The resulting three spectra represent a background for this measurement. An experimental method for obtaining these three spectra is described and results are reported for 2" x 2", 5" x 5", 6" x 6", and 1" x 6" NaI detectors using the thermal neutron beam of the NCSU PULSTAR nuclear reactor. In addition, Monte Carlo simulation programs have been developed and used for simulating these spectra. Good results have been obtained by the Monte Carlo method for the two radioisotope spectra, and it is anticipated that good results will also be obtained for the prompt gamma-ray spectrum when the I and Na coincidence schemes are known. PMID:11003483

  16. NaI detector neutron activation spectra for PGNAA applications

    Gardner, R.P. E-mail: gardner@ncsu.edu; Sayyed, El; Zheng Yuanshui; Hayden, Stephanie; Mayo, C.W

    2000-11-15

    When NaI detectors are used in prompt gamma-ray neutron activation analysis devices, they are activated by neutrons that penetrate the detector. While thermal neutron filters like boron or lithium can be used to reduce this activation, it can never be completely eliminated by this approach since high energy neutrons can penetrate the detector and thermalize inside it. This activation results in the emission of prompt gamma rays from both the I and Na and the production of the radioisotopes {sup 128}I and {sup 24}Na that subsequently decay and emit their characteristic beta particles and gamma rays. The resulting three spectra represent a background for this measurement. An experimental method for obtaining these three spectra is described and results are reported for 2x2, 5x5, 6x6, and 1x6 NaI detectors using the thermal neutron beam of the NCSU PULSTAR nuclear reactor. In addition, Monte Carlo simulation programs have been developed and used for simulating these spectra. Good results have been obtained by the Monte Carlo method for the two radioisotope spectra, and it is anticipated that good results will also be obtained for the prompt gamma-ray spectrum when the I and Na coincidence schemes are known.

  17. Characterization of active CMOS sensors for capacitively coupled pixel detectors

    Hirono, Toko; Gonella, Laura; Janssen, Jens; Hemperek, Tomasz; Huegging, Fabian; Krueger, Hans; Wermes, Norbert [Institute of Physics, University of Bonn (Germany); Peric, Ivan [Institut fuer Prozessdatenverarbeitung und Elektronik, Karlsruher Institut fuer Technologie, Karlsruhe (Germany)

    2015-07-01

    Active CMOS pixel sensor is one of the most attractive candidates for detectors of upcoming particle physics experiments. In contrast to conventional sensors of hybrid detectors, signal processing circuit can be integrated in the active CMOS sensor. The characterization and optimization of the pixel circuit are indispensable to obtain a good performance from the sensors. The prototype chips of the active CMOS sensor were fabricated in the AMS 180nm and L-Foundry 150 nm CMOS processes, respectively a high voltage and high resistivity technology. Both chips have a charge sensitive amplifier and a comparator in each pixel. The chips are designed to be glued to the FEI4 pixel readout chip. The signals from 3 pixels of the prototype chips are capacitively coupled to the FEI4 input pads. We have performed lab tests and test beams to characterize the prototypes. In this presentation, the measurement results of the active CMOS prototype sensors are shown.

  18. Neutron spectra unfolding from measured detector activations

    Our knowledge of the neutron spectrum in irradiation facilities essentially rests on the calculation and on the unfolding resp. adjustment based on measured activations, more generally said reactions rates, since the other direct or indirect experimental methods here frequently are not applicable on account of technical reasons. In this situation the neutronic calculation by no means renders superfluous the unfolding because the measurements can confirm or possibly correct resp. improve the calculational results. The FORTRAN code SAND-MX2 is a contribution of the KFA to the international repertoire of unfolding codes. With regard to its contents it is one of the newer versions of the original code SAND-II which are presently used as SAND-II also in the laboratories of several countries as especially practice related unfolding calculational methods. This report may serve as an instruction manual for the routinely neutron spectrum unfolding by means of the code SAND-MX2. It appeared to us not to be superfluous in addition to the above mentioned aim also to give a general view of the present situation in unfolding technique and to touch shortly the other advanced methods because we believed thereby also to give a better understanding of the characteristic features of our programme. In some laboratories several of the here described calculational programmes are alternatively in current use for the purpose of giving a greater confidence to the result of the neutron spectrum unfolding in question. (orig.)

  19. Measurement of nuclear activity with Ge detectors and its uncertainty

    Cortes, C A P

    1999-01-01

    presented in the fifth chapter and they are applied to establish the optimum conditions for the measurement of the activity of a gamma transmitter isolated radioactive source with a spectrometer with germanium detector. (Author) The objective of this work is to analyse the influence magnitudes which affect the activity measurement of gamma transmitter isolated radioactive sources. They prepared by means of the gravimetric method, as well as, determining the uncertainty of such measurement when this is carried out with a gamma spectrometer system with a germanium detector. This work is developed in five chapters: In the first one, named Basic principles it is made a brief description about the meaning of the word Measurement and its implications and the necessaries concepts are presented which are used in this work. In the second chapter it is exposed the gravimetric method used for the manufacture of the gamma transmitter isolated radioactive sources, it is tackled the problem to determine the main influence ...

  20. Beryllium neutron activation detector for pulsed DD fusion sources

    A compact fast neutron detector based on beryllium activation has been developed to perform accurate neutron fluence measurements on pulsed DD fusion sources. It is especially well suited to moderate repetition-rate (9Be(n,α)6He cross-section, energy calibration of the proportional counters, and numerical simulations of neutron interactions and beta-particle paths using MCNP5. The response function R(En) is determined over the neutron energy range 2-4 MeV. The count rate capability of the detector has been studied and the corrections required for high neutron fluence measurements are discussed. For pulsed DD neutron fluencies >3×104 cm-2, the statistical uncertainty in the fluence measurement is better than 1%. A small plasma focus device has been employed as a pulsed neutron source to test two of these new detectors, and their responses are found to be practically identical. Also the level of interfering activation is found to be sufficiently low as to be negligible.

  1. Calibration of the active radiation detector for Spacelab-One

    1982-01-01

    The flight models of the active radiation detector (ARD) for the ENV-01 environmental monitor were calibrated using gamma radiation. Measured sensitivities of the ion chambers were 6.1 + or - 0.3 micron rad per count for ARD S/N1, and 10.4 + or - 0.5 micron rad per count for ARD S/N2. Both were linear over the measured range 0.10 to 500 m/rad hour. The particle counters (proportional counters) were set to respond to approximately 85% of minimum ionizing particles of unit charge passing through them. These counters were also calibrated in the gamma field.

  2. Measurement of nuclear activity with Ge detectors and its uncertainty

    The objective of this work is to analyse the influence magnitudes which affect the activity measurement of gamma transmitter isolated radioactive sources. They prepared by means of the gravimetric method, as well as, determining the uncertainty of such measurement when this is carried out with a gamma spectrometer system with a germanium detector. This work is developed in five chapters: In the first one, named Basic principles it is made a brief description about the meaning of the word Measurement and its implications and the necessaries concepts are presented which are used in this work. In the second chapter it is exposed the gravimetric method used for the manufacture of the gamma transmitter isolated radioactive sources, it is tackled the problem to determine the main influence magnitudes which affect in the measurement of their activity and the respective correction factors and their uncertainties are deduced. The third chapter describes the gamma spectrometry system which is used in this work for the measurement of the activity of isolated sources and also its performance and experimental arrangement that it is used. In the fourth chapter are applied the three previous items with the object of determining the uncertainty which would be obtained in the measurement of an isolated radioactive source elaborated with the gravimetric method in the experimental conditions less favourable predicted above the obtained results from the chapter two. The conclusions are presented in the fifth chapter and they are applied to establish the optimum conditions for the measurement of the activity of a gamma transmitter isolated radioactive source with a spectrometer with germanium detector. (Author)

  3. Activity on improving performance of time-of-flight detector at CDF

    Menzione, A; Prokoshin, F; Tokar, S; Vataga, E

    2002-01-01

    The paper describes activity on improving the time resolution of the Time-of-Flight detector at CDF. The main goal of the detector is the identification of kaons and pions for b-quark (B-meson) flavour tagging. Construction of the detector has been described as well as proposals on detector design changes to improve its time resolution. Monte Carlo simulation of the detector response to MIP was performed. The results of the simulation showed that the proposed modifications (at least with currently available materials) bring modest or no improvement of the detector time resolution. An automated set-up was assembled to test and check out the changes in the electronic readout system of the detector. Sophisticated software has been developed for this set-up to provide control of the system as well as processing and presentation of data from the detector. This software can perform various tests using different implementations of the hardware set-up

  4. Activity on improving performance of time-of-flight detector at CDF

    The paper describes activity on improving the time resolution of the Time-of-Flight detector at CDF. The main goal of the detector is the identification of kaons and pions for b-quark (B-meson) flavour tagging. Construction of the detector has been described as well as proposals on detector design changes to improve its time resolution. Monte Carlo simulation of the detector response to MIP was performed. The results of the simulation showed that the proposed modifications (at least with currently available materials) bring modest or no improvement of the detector time resolution. An automated set-up was assembled to test and check out the changes in the electronic readout system of the detector. Sophisticated software has been developed for this set-up to provide control of the system as well as processing and presentation of data from the detector. This software can perform various tests using different implementations of the hardware set-up

  5. Glasses as active and passive components for scintillating fiber detectors

    Scintillating fibers are of growing interest in high energy physics for applications in calorimetry and in tracking detectors. At present plastic scintillating fibers are mainly used in these applications because of their high light yield and their fast decay rates; however, in thin fibers, required for high spatial resolution, these suffer from low attenuation lengths. Moreover, cross-talk is still a severe problem. As alternatives the authors will discuss the following two concepts: (1) using Ce- and Tb-doped multicomponent glasses as active core material of glass fibers and (2) using liquid scintillator filled glass capillary arrays. The optical properties of the rare earth doped glasses are described and the scintillation efficiency of the fibers and fiber bundles utilizing these glasses as core material are presented. Broad applications appear to be possible with liquid scintillator filled capillary arrays. Suitable liquid scintillators with high refractive index solvents and locally emitting solutes with high yields, short decay times and large Stokes-shifts are available. Arrays can be produced with and without extra mural absorber in various sizes and shapes. Theoretical estimates show that reflection losses at the liquid/glass interface do not effect the overall transmission up to length/diameter ratios of 105. In addition recent results have shown that the system resists radiation doses in the 100 kGy range. Further experimental results obtained at CERN with these arrays will be discussed

  6. Impact of detector-element active-area shape and fill factor on super-resolution

    Russell C. Hardie; Douglas R. Droege; Alexander J Dapore; Mark E Greiner

    2015-01-01

    In many undersampled imaging systems, spatial integration from the individual detector elements is the dominant component of the system point spread function (PSF). Conventional focal plane arrays (FPAs) utilize square detector elements with a nearly 100% fill factor, where fill factor is defined as the fraction of the detector element area that is active in light detection. A large fill factor is generally considered to be desirable because more photons are collected for a given pitch, and t...

  7. DEPFET Active Pixel Detectors for a Future Linear e(+}e({-)) Collider

    Alonso, O.; Casanova, R.; Dieguez, A.; Dingfelder, J.; Hemperek, T.; Kishishita, T.; Kleinohl, T.; Koch, M.; Kruger, H.; Lemarenko, M.; Lutticke, F.; Marinas, C.; Schnell, M.; Wermes, N.; Campbell, A.; Ferber, T.; Kleinwort, C.; Niebuhr, C.; Soloviev, Y.; Steder, M.; Volkenborn, R.; Yaschenko, S.; Fischer, P.; Kreidl, C.; Peric, I.; Knopf, J.; Ritzert, M.; Curras, E.; Lopez-Virto, A.; Moya, D.; Vila, I.; Boronat, M.; Esperante, D.; Fuster, J.; Garcia, I. Garcia; Lacasta, C.; Oyanguren, A.; Ruiz, P.; Timon, G.; Vos, M.; Gessler, T.; Kuhn, W.; Lange, S.; Munchow, D.; Spruck, B.; Frey, A.; Geisler, C.; Schwenker, B.; Wilk, F.; Barvich, T.; Heck, M.; Heindl, S.; Lutz, O.; Muller, Th.; Pulvermacher, C.; Simonis, H. J.; Weiler, T.; Krausser, T.; Lipsky, O.; Rummel, S.; Schieck, J.; Schluter, T.; Ackermann, K.; Andricek, L.; Chekelian, V.; Chobanova, V.; Dalseno, J.; Kiesling, C.; Koffmane, C.; Gioi, L. Li; Moll, A.; Moser, H. G.; Muller, F.; Nedelkovska, E.; Ninkovic, J.; Petrovics, S.; Prothmann, K.; Richter, R.; Ritter, A.; Ritter, M.; Simon, F.; Vanhoefer, P.; Wassatsch, A.; Dolezal, Z.; Drasal, Z.; Kodys, P.; Kvasnicka, P.; Scheirich, J.

    2013-04-01

    The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at future collider experiments. The characterization of detector prototypes has proven that the key principle, the integration of a first amplification stage in a detector-grade sensor material, can provide a comfortable signal to noise ratio of over 40 for a sensor thickness of 50-75 $\\mathrm{\\mathbf{\\mu m}}$. ASICs have been designed and produced to operate a DEPFET pixel detector with the required read-out speed. A complete detector concept is being developed, including solutions for mechanical support, cooling and services. In this paper the status of DEPFET R & D project is reviewed in the light of the requirements of the vertex detector at a future linear $\\mathbf{e^+ e^-}$ collider.

  8. DEPFET active pixel detectors for a future linear e+e− collider

    Vos, M

    2010-01-01

    The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at future collider experiments. The characterization of detector prototypes has proven that the key principle, the integration of a first amplification stage in a detector-grade sensor material, can provide a comfortable signal to noise ratio of over 40 for a sensor thickness of 50-75 µm. ASICs have been designed and produced to operate a DEPFET pixel detector with the required read-out speed. A complete detector concept is being developed, including solutions for mechanical support, cooling and services. In this paper the status of DEPFET R & D project is reviewed in the light of the requirements of the vertex detector at a future linear e^+e^− collider.

  9. Active noise canceling system for mechanically cooled germanium radiation detectors

    Nelson, Karl Einar; Burks, Morgan T

    2014-04-22

    A microphonics noise cancellation system and method for improving the energy resolution for mechanically cooled high-purity Germanium (HPGe) detector systems. A classical adaptive noise canceling digital processing system using an adaptive predictor is used in an MCA to attenuate the microphonics noise source making the system more deployable.

  10. Feasibility Study of an Active Sandwich Detector for duel-energy imaging

    Kim, Dongwoon; Han, Jongchul; Kim, Hokyung [Pusan National Univ., Busan, (Korea, Republic of)

    2013-10-15

    In this study, we investigate a feasibility of sandwich detector based on flat-panel detectors for dual-energy x-ray imaging, particularly for industry application such as a foreign substance detection in noodles. Dual-energy (DE) imaging can remove overlapping background structures that obscure the detection and characterization of target object in radiographs. Although the theoretical framework describing DE imaging had been initialized in the late of 1970s, its renewed interest has been in the spotlight since large area flat-panel detectors capable of real-time imaging with high detective quantum efficiency had been commercially available. DE x-ray imaging based on the fast kVp-switching technique (also known as 'double shot or double-exposure' DE imaging), which acquires low- and high-energy projections in successive exposures, is therefore now available in clinic. Figure 1(a), (b) and (c) show preparations of 'single shot or single-exposure' DE imaging detector, which acquires low- and high-energy projections simultaneously from two detectors arranged in upper and lower layers. Since two detectors are doubly layered, we named it 'the sandwich detector'. While sandwich-detector configurations based on 'passive' film-screen combinations or storage phosphors were often reported, there has not been sufficient attention paid to the use of 'active' solid-state detectors.

  11. The effect of the detector thickness on the minimum detectable activity of lung counters

    In the recent years, the trend is that WBC (Whole Body Counting) laboratories are replacing old Phoswich detectors, which suffer from poor resolution, to HPGe detectors. It was expected that counting with HPGe detectors will improve the Minimum Detectable Activity (MDA) considerably, due to the very significant improvement of the detectors resolution. The better resolution reduces the background region, and hence the background counting, which is the main factor that determines the MDA. NRC-Negev WBC laboratory upgraded lately the old Phoswich detectors with a system of new HPGe detectors. In the present work a study was done to check in more depth the factors influencing the MDA, especially the contribution of the thickness of the detector. Monte Carlo simulations were used to calculate the MDA and to analyze the effects of the detectors' thickness and type on the MDA value. The present work summarizes the results of this study. It is shown that the advantage of HPGe systems seems to be strongly dependent on the detector thickness and the photons energy

  12. Feasibility Study of an Active Sandwich Detector for duel-energy imaging

    In this study, we investigate a feasibility of sandwich detector based on flat-panel detectors for dual-energy x-ray imaging, particularly for industry application such as a foreign substance detection in noodles. Dual-energy (DE) imaging can remove overlapping background structures that obscure the detection and characterization of target object in radiographs. Although the theoretical framework describing DE imaging had been initialized in the late of 1970s, its renewed interest has been in the spotlight since large area flat-panel detectors capable of real-time imaging with high detective quantum efficiency had been commercially available. DE x-ray imaging based on the fast kVp-switching technique (also known as 'double shot or double-exposure' DE imaging), which acquires low- and high-energy projections in successive exposures, is therefore now available in clinic. Figure 1(a), (b) and (c) show preparations of 'single shot or single-exposure' DE imaging detector, which acquires low- and high-energy projections simultaneously from two detectors arranged in upper and lower layers. Since two detectors are doubly layered, we named it 'the sandwich detector'. While sandwich-detector configurations based on 'passive' film-screen combinations or storage phosphors were often reported, there has not been sufficient attention paid to the use of 'active' solid-state detectors

  13. Activation Spectrometry of Fast Neutrons by IAEA Threshold Detectors at Neutron Generators

    The suitability of the IAEA set of threshold detectors for neutron accident purposes was investigated. A generator producing 14.3-MeV neutrons by the T(d, n)4He reaction was employed for this purpose. 237Np, 232Th, 58Ni and 27Al threshold detectors were used. The induced activity was determined by gamma spectrometry using a multichannel analyser. Fast neutron spectra have been estimated from the experimental results. Measurements at the surface and at the depth of a phantom were provided. Some difficulties from low induced and fission activities (caused by the small neutron flux density and the light weight of the detectors) are pointed out. (author)

  14. Radiochemical evaluation of activation detectors for fluence determination of fast neutrons

    For monitoring of radiation embrittlement of reactor pressure vessels, irradiation experiments to determine the fluence of fast neutrons are carried out. The activation detectors used for this purpose are based on the following nuclear reactions: Fe54(n,p)Mn54 Nb93(n,n')Nb93m Th232(n,f)Cs137. The criteria, which led to the selection of these activation detectors, are discussed. The evaluation via chemical preparation and radiation measurement as well as the problems of calibration yield control and interferences are described. The experience made to date shows that - depending on detector and effort - the disintegration rates can be measured during routine measurements with an accuracy of 5 to 25%. The error range of the determined neutron fluence is 15 to 30%. The results of the three activation detectors are in agreement within this error range. (orig.)

  15. Cherenkov detector of the water flow activated by 14 MeV neutrons

    For the purpose of monitoring the D-T neutrons in the system using neutron activation of flowing water, a new approach was proposed. It enables to solve problems associated with the response delay and temporal resolution, which are the most important drawbacks of the previous approach. In support of this idea, the first experimental phase was completed. The response of the detector to the Cherenkov light from the 16N was studied comprehensively. It was concluded, that the water Cherenkov detector is very efficient in measuring the 16N activity, due to: high counting efficiency; absence of the scintillation detector; and simplicity of the method. The present study elaborates upon the feasibility and effectiveness of utilizing the Cherenkov radiation detector in the D-T neutron monitoring system. (author)

  16. Study of the possibility of dielectric detectors' utilization for the measurement of radon's activity

    At present, much attention has been paid to the measurement of concentration of radon in water, soil and atmosphere as radon-222 is decay product of uranium and can give information on the pollution of atmosphere, geophysical and geochemical process taking place in earth. Alpha activity of radon is registered by the different method including dielectric detector. This method differs simplicity and economical utilization. Irradiated detectors etched in 20 per cent solution Na OH at temperature 60 degrees centigrade during 80 minutes

  17. Neutron activation detector saturation activities measured in the AAEC research reactor HIFAR

    Titanium and cobalt wires are irradiated with radiation damage specimens in each reactor period to determine variations in neutron flux densities. The results from these monitors constitute a considerable body of data with good statistical significance. However, a difficulty encountered when using measurements collected over a number of reactor periods for determining flux depression factors or cadmium ratios is accounting for the effects on saturation activities of different irradiation conditions, in particular the continuously changing fuel burn-up rates. This difficulty was overcome by correlating the saturation activities of (n,γ) reactions with the number of fissions in the fuel. The experimental saturation activities so correlated enable (1) flux depression factors to be obtained for cobalt and silver wires, relative to thin foils, and (2) use of these flux depression factors and others quoted in the literature to calculate the ratio of saturation activities of Co and Ag wires. Finally, reference is made to the potential usefulness of the 123Sb(n,γ) reaction as a resonance detector given that a new method for making thin monitors can be readily applied to antimony

  18. Physical characterization and performance comparison of active- and passive-pixel CMOS detectors for mammography.

    Elbakri, I A; McIntosh, B J; Rickey, D W

    2009-03-21

    We investigated the physical characteristics of two complementary metal oxide semiconductor (CMOS) mammography detectors. The detectors featured 14-bit image acquisition, 50 microm detector element (del) size and an active area of 5 cm x 5 cm. One detector was a passive-pixel sensor (PPS) with signal amplification performed by an array of amplifiers connected to dels via data lines. The other detector was an active-pixel sensor (APS) with signal amplification performed at each del. Passive-pixel designs have higher read noise due to data line capacitance, and the APS represents an attempt to improve the noise performance of this technology. We evaluated the detectors' resolution by measuring the modulation transfer function (MTF) using a tilted edge. We measured the noise power spectra (NPS) and detective quantum efficiencies (DQE) using mammographic beam conditions specified by the IEC 62220-1-2 standard. Our measurements showed the APS to have much higher gain, slightly higher MTF, and higher NPS. The MTF of both sensors approached 10% near the Nyquist limit. DQE values near dc frequency were in the range of 55-67%, with the APS sensor DQE lower than the PPS DQE for all frequencies. Our results show that lower read noise specifications in this case do not translate into gains in the imaging performance of the sensor. We postulate that the lower fill factor of the APS is a possible cause for this result. PMID:19242050

  19. Cosmic-ray-induced background intercomparison with actively shielded HPGe detectors at underground locations

    Szuecs, T. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Institute for Nuclear Research (MTA Atomki), Debrecen (Hungary); Bemmerer, D.; Wagner, A.; Weinberger, D. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Reinhardt, T.P.; Zuber, K. [Technische Universitaet Dresden, Institute for Nuclear and Particle Physics, Dresden (Germany); Schmidt, K.; Takacs, M.P.; Wagner, L. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Technische Universitaet Dresden, Institute for Nuclear and Particle Physics, Dresden (Germany)

    2015-03-01

    The main background above 3MeV for in-beam nuclear astrophysics studies with γ -ray detectors is caused by cosmic-ray-induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray-induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45m and 1400m, respectively. (orig.)

  20. Cosmic-ray-induced background intercomparison with actively shielded HPGe detectors at underground locations

    The main background above 3MeV for in-beam nuclear astrophysics studies with γ -ray detectors is caused by cosmic-ray-induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray-induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45m and 1400m, respectively. (orig.)

  1. Monte Carlo simulation of GM probe and NaI detector efficiency for surface activity measurements

    This paper deals with the direct measurement of total (fixed plus removable) surface activity in the presence of interfering radiation fields. Two methods based on Monte Carlo simulations are used: one for a Geiger–Muller (GM) ionisation probe and the other for sodium iodide (NaI) detector with lead collimators; equations for the most general case and the geometry models for Monte Carlo simulation of both (GM and NaI) detectors are employed. Finally, an example of application is discussed. - Highlights: • Two methods for direct measurements of beta/gamma surface activity are proposed. • Monte Carlo simulated efficiency of detectors was validated and tested. • The calculated and measured efficiencies of detection systems were very similar. • The comparison between two different methods shows good agreement. • Methods can be used for rapid and accurate direct measurements of surface activity

  2. Cosmic-ray induced background intercomparison with actively shielded HPGe detectors at underground locations

    Szücs, T; Reinhardt, T P; Schmidt, K; Takács, M P; Wagner, A; Wagner, L; Weinberger, D; Zuber, K

    2015-01-01

    The main background above 3\\,MeV for in-beam nuclear astrophysics studies with $\\gamma$-ray detectors is caused by cosmic-ray induced secondaries. The two commonly used suppression methods, active and passive shielding, against this kind of background were formerly considered only as alternatives in nuclear astrophysics experiments. In this work the study of the effects of active shielding against cosmic-ray induced events at a medium deep location is performed. Background spectra were recorded with two actively shielded HPGe detectors. The experiment was located at 148\\,m below the surface of the Earth in the Reiche Zeche mine in Freiberg, Germany. The results are compared to data with the same detectors at the Earth's surface, and at depths of 45\\,m and 1400\\,m, respectively.

  3. Preparation of neutron-activated xenon for liquid xenon detector calibration

    We report the preparation of neutron-activated xenon for the calibration of liquid xenon (LXe) detectors. Gamma rays from the decay of xenon metastable states, produced by fast neutron activation, were detected and their activities measured in a LXe scintillation detector. Following a 5-day activation of natural xenon gas with a 252Cf (4x105n/s) source, the activities of two gamma ray lines at 164 and 236 keV, from 131mXe and 129mXe metastable states, were measured at about 95 and 130 Bq/kg, respectively. We also observed three additional lines at 35, 100 and 275 keV, which decay away within a few days. No long-lifetime activity was observed after the neutron activation

  4. Calibration of activation detectors in a monoenergetic neutron beam. Contribution to criticality dosimetry

    Activation detectors have been calibrated for critical dosimetry applications. Measurements are made using a monoenergetic neutron flux. 14 MeV neutrons obtained par (D-T) reaction are produced by 150 kV accelerator. Neutron flux determined by different methods leads us to obtain an accuracy better than 6%. The present dosimetric system (Activation Neutron Spectrometer - SNAC) gives few informations in the (10 keV - 2 MeV) energetic range. The system has been improved and modified so that SNAC detectors must be read out by gamma spectrometer

  5. Background intercomparison with an active shielded HPGE detector extended to Freiberg mine in Germany

    A key requirement for underground nuclear astrophysics experiments is the very low background level in germanium detectors. The reference for these purposes is the world's so far only underground accelerator laboratory for nuclear astrophysics, LUNA. LUNA is located deep underground in the Gran Sasso laboratory in Italy, shielded from cosmic rays by 1400m of rock. The background at LUNA was studied in detail using an escape-suppressed Clovertype HPGe detector. Exactly the same detector was subsequently transported to the Felsenkeller underground laboratory in Dresden, shielded by 45m of rock, and the background was shown to be only a factor of three higher than at LUNA when comparing the escape-suppressed spectra, with interesting consequences for underground nuclear astrophysics [2]. As the next step of a systematic study of the effects of a combination of active and passive shielding on the cosmic ray induced background, this detector has recently been brought to the 'Reiche Zeche' mine in Freiberg, Germany, shielded by 150m of rock. The data available with one and the same actively shielded HPGe detector at the Earth's surface and below 45, 150, and 1400m of rock allow getting a general understanding of the effects of active shielding with depth. Supported by the Helmholtz Association (HGF) through the Nuclear Astrophysics Virtual Institute (HGF VH-VI-417). (author)

  6. Provisional shielding for laboratory measurements of low level activities with semiconductor detectors

    The application of semiconductor spectrometry in low level counting requires the use of detector shielding to weaken the effect of ambient sources of ionizing radiation. The design is described of provisional shields of lead bricks for three different types of high-purity Ge detectors by Canberra. In the configuration of six polyethylene vessels around the detector with a total sample volume of 1200 ml, minimal detectable activities were determined of selected radionuclides. The experiment showed that the determination of minimal detectable activity in this configuration shows sufficient values for determining the content of natural and artificial radionuclides for monitoring samples from the environment of nuclear power plants. (Z.M.). 5 figs., 3 tabs., 2 refs

  7. Signal formation and active edge studies of 3D silicon detector technology

    Kok, Angela

    3D detectors and devices with an ‘active edge’ were fabricated at the Stanford Nanofabrication Facility. Characteristics such as time response and edge sensitivity were studied. The induced signals from a 3D detector were studied using a fast, low-noise transimpedance amplifier. The rise time of the output signal obtained for a minimum ionising particle was faster than 4 ns at room temperature and 2 ns at 130K. This is in agreement with earlier calculations of 3D detectors that predicted the charge collection time to be between one to two ns. The first understanding of signal formation in a 3D detector was achieved by comparing measurements with a full system simulation. The differences in collection behaviour between electrons and holes were also understood and verified by measurement. Edge sensitivity was measured at the CERN SPS, using a high energy muon beam and a silicon telescope. The detector was measured to be efficient up to less than 4 μm from its physical edge. This confirmed that active edge ...

  8. The Effect of a Voice Activity Detector on the Speech Enhancement

    Dau, Torsten; Catic, Jasmina; Buchholz, Jörg;

    2010-01-01

    A multimicrophone speech enhancement algorithm for binaural hearing aids that preserves interaural time delays was proposed recently. The algorithm is based on multichannel Wiener filtering and relies on a voice activity detector (VAD) for estimation of second-order statistics. Here, the effect of...

  9. Description of methods for making activation detectors for use in nuclear reactors

    A brief description of methods currently used for making activation detectors, thin films and various deposits used in nuclear reactors. The thicknesses required vary from about a few tenths of a micron to a few tenths of a millimeter. Different techniques are used for fixing the large variety of elements: rolling, moulding, painting, electrolysis, vacuum deposition, thin films, wires, enamels, protective linings, etc. (authors)

  10. The Dexela 2923 CMOS X-ray detector: A flat panel detector based on CMOS active pixel sensors for medical imaging applications

    Konstantinidis, A. C.; Szafraniec, M. B.; Speller, R.D.; Olivo, A.

    2012-01-01

    Complementary metal-oxide-semiconductors (CMOS) active pixel sensors (APS) have been introduced recently in many scientific applications. This work reports on the performance (in terms of signal and noise transfer) of an X-ray detector that uses a novel CMOS APS which was developed for medical X-ray imaging applications. For a full evaluation of the detector's performance, electro-optical and X-ray characterizations were carried out. The former included measuring read noise, full well capacit...

  11. Solid-state radiation detectors for active personal dosimetry and radiations source tracking

    We report on the design of the readout electronics using PIN diode radiation detector of 5 mm thickness for nuclear safety and active personal dosimetry. Our effort consisted in designing and fabricating the electronics to reflect the needs of gamma radiations dosimetry and hybrids PIN diode arrays for charged particle detectors. We report results obtained during testing and characterizing the new devices in gamma fields, operating at room temperature. There were determined the energy spectrum resolution, radiation hardness and readout rate. Also, data recording methods and parallel acquisition problems from a transducer matrix are presented. (authors)

  12. Thick activation detectors for neutron spectrometry using different unfolding methods: sensitivity analysis and dose calculation

    This paper discusses the use of threshold detectors of extended sizes for low intensity neutron fields' characterization. The detectors were tested by the measurement of the neutron spectrum of an 241Am–Be source. Integral quantities characterizing the neutron field, required for radiological protection, have been derived by unfolding the measured data. A good agreement is achieved between the obtained results and those deduced using Bonner spheres. In addition, a sensitivity analysis of the results to the deconvolution procedure is given. - Highlights: ► Low intensity neutron fields' characterization using thick threshold detectors. ► Low activity 241Am–Be neutron source spectrum measurement. ► Integral quantities required for radiological protection have been derived. ► The results are in good agreement with those deduced using Bonner spheres. ► The results are not very sensitive to the chosen deconvolution procedure.

  13. Needle Type Solid State Detectors for In-Vivo Measurement of Tracer Activity

    A set of miniature detector probes for in-vivo-measurement of beta and gamma tracer activity is described. The probes use a lithium-compensated p-i-n silicon detector as sensing element. The standard 'needle probe' contains a cylindrical detector 0.9 mm in diameter and 3 mm long, enclosed in a stainless steel tube 1.1 mm in outer diameter and with walls 0. 05 mm thick. For particular applications several modified types have been developed: probes with larger sensing elements, probes with extra thin walls for low-energy beta detection, probes with two or three sensing elements in the same needle and probes containing a movable sensing element. This report describes the construction and the properties of the different needle probes

  14. Needle Type Solid State Detectors for In-Vivo Measurement of Tracer Activity

    Lauber, A. [AB Atomenergi, Nykoeping (Sweden); Wolgast, W. [Univ. of Uppsala (Sweden). Inst. of Physiology and Medical Biophysics

    1970-07-15

    A set of miniature detector probes for in-vivo-measurement of beta and gamma tracer activity is described. The probes use a lithium-compensated p-i-n silicon detector as sensing element. The standard 'needle probe' contains a cylindrical detector 0.9 mm in diameter and 3 mm long, enclosed in a stainless steel tube 1.1 mm in outer diameter and with walls 0. 05 mm thick. For particular applications several modified types have been developed: probes with larger sensing elements, probes with extra thin walls for low-energy beta detection, probes with two or three sensing elements in the same needle and probes containing a movable sensing element. This report describes the construction and the properties of the different needle probes.

  15. A universal setup for active control of a single-photon detector

    Liu, Qin; Skaar, Johannes [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Lamas-Linares, Antía; Kurtsiefer, Christian [Centre for Quantum Technologies and Department of Physics, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Makarov, Vadim, E-mail: makarov@vad1.com [Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Gerhardt, Ilja, E-mail: ilja@quantumlah.org [Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart (Germany)

    2014-01-15

    The influence of bright light on a single-photon detector has been described in a number of recent publications. The impact on quantum key distribution (QKD) is important, and several hacking experiments have been tailored to fully control single-photon detectors. Special attention has been given to avoid introducing further errors into a QKD system. We describe the design and technical details of an apparatus which allows to attack a quantum-cryptographic connection. This device is capable of controlling free-space and fiber-based systems and of minimizing unwanted clicks in the system. With different control diagrams, we are able to achieve a different level of control. The control was initially targeted to the systems using BB84 protocol, with polarization encoding and basis switching using beamsplitters, but could be extended to other types of systems. We further outline how to characterize the quality of active control of single-photon detectors.

  16. Use of active-edge silicon detectors as X-ray beam monitors

    Silicon detectors have been developed which are active to within several microns of the physical edge of the detector. These active-edge devices can be placed near an intense X-ray beam to accurately measure the X-ray beam properties. In addition, they can be fabricated in a variety of geometries that will be useful for monitoring the intensity, profile, and position of synchrotron X-ray beams. One shape is a detector with a through hole surrounded by four active elements. The hole allows the intense X-ray beam to go through the center while the four elements can detect any change in the position or dispersion of the beam. Another shape is a rectangular 5 mm longx0.5 mm wide device with a set of four elements that are 100 μm wide. These devices could be mounted on the upstream side of the jaws of an x-y collimating slit to measure the intensity profile of the beam that each jaw of the slit is stopping. Small detectors could also be mounted in a cylindrical beam stop to give on-line beam intensity measurements. A variety of different geometries were tested at beamline 10.3.1 of the Advanced Light Source using a 12.5 keV X-ray beam. They have wide dynamic range, excellent position sensitivity and low sensitivity to radiation damage

  17. Calibration of Cherenkov detectors for monoenergetic photon imaging in active interrogation applications

    Rose, P.B., E-mail: prose6@gatech.edu; Erickson, A.S., E-mail: anna.erickson@me.gatech.edu

    2015-11-01

    Active interrogation of cargo containers using monoenergetic photons offers a rapid and low-dose approach to search for shielded special nuclear materials. Cherenkov detectors can be used for imaging of the cargo provided that gamma ray energies used in interrogation are well resolved, as the case in {sup 11}B(d,n-γ){sup 12}C reaction resulting in 4.4 MeV and 15.1 MeV photons. While an array of Cherenkov threshold detectors reduces low energy background from scatter while providing the ability of high contrast transmission imaging, thus confirming the presence of high-Z materials, these detectors require a special approach to energy calibration due to the lack of resolution. In this paper, we discuss the utility of Cherenkov detectors for active interrogation with monoenergetic photons as well as the results of computational and experimental studies of their energy calibration. The results of the studies with sources emitting monoenergetic photons as well as complex gamma ray spectrum sources, for example {sup 232}Th, show that calibration is possible as long as the energies of photons of interest are distinct.

  18. Dead layer and active volume determination for GERDA Phase II detectors

    Lehnert, Bjoern [TU Dresden (Germany); Collaboration: GERDA-Collaboration

    2013-07-01

    The GERDA experiment investigates the neutrinoless double beta decay of {sup 76}Ge and is currently running Phase I of its physics program. Using the same isotope as the Heidelberg Moscow (HDM) experiment, GERDA aims to directly test the claim of observation by a subset of the HDM collaboration. For the update to Phase II of the experiment in 2013, the collaboration organized the production of 30 new Broad Energy Germanium (BEGe) type detectors from original 35 kg enriched material and tested their performance in the low background laboratory HADES in SCK.CEN, Belgium. With additional 20 kg of detectors, GERDA aims to probe the degenerated hierarchy scenario. One of the crucial detector parameters is the active volume (AV) fraction which directly enters into all physics analysis. This talk presents the methodology of dead layer and AV determination with different calibration sources such as {sup 241}Am, {sup 133}Ba, {sup 60}Co and {sup 228}Th and the results obtained for the new Phase II detectors. Furthermore, the AV fraction turned out to be the largest systematic uncertainty in the analysis of Phase I data which makes it imperative to reduce its uncertainty for Phase II. This talk addresses the major contributions to the AV uncertainty and gives an outlook for improvements in Phase II analysis.

  19. Dead layer and active volume determination for GERDA Phase II detectors

    The GERDA experiment investigates the neutrinoless double beta decay of 76Ge and is currently running Phase I of its physics program. Using the same isotope as the Heidelberg Moscow (HDM) experiment, GERDA aims to directly test the claim of observation by a subset of the HDM collaboration. For the update to Phase II of the experiment in 2013, the collaboration organized the production of 30 new Broad Energy Germanium (BEGe) type detectors from original 35 kg enriched material and tested their performance in the low background laboratory HADES in SCK.CEN, Belgium. With additional 20 kg of detectors, GERDA aims to probe the degenerated hierarchy scenario. One of the crucial detector parameters is the active volume (AV) fraction which directly enters into all physics analysis. This talk presents the methodology of dead layer and AV determination with different calibration sources such as 241Am, 133Ba, 60Co and 228Th and the results obtained for the new Phase II detectors. Furthermore, the AV fraction turned out to be the largest systematic uncertainty in the analysis of Phase I data which makes it imperative to reduce its uncertainty for Phase II. This talk addresses the major contributions to the AV uncertainty and gives an outlook for improvements in Phase II analysis.

  20. Prototype Active Silicon Sensor in 150 nm HR-CMOS Technology for ATLAS Inner Detector Upgrade

    Rymaszewski, Piotr; Barbero, Marlon; Breugnon, Patrick; Godiot, Stépahnie; Gonella, Laura; Hemperek, Tomasz; Hirono, Toko; Hügging, Fabian; Krüger, Hans; Liu, Jian; Pangaud, Patrick; Peric, Ivan; Rozanov, Alexandre; Wang, Anqing; Wermes, Norbert

    2016-01-01

    The LHC Phase-II upgrade will lead to a significant increase in luminosity, which in turn will bring new challenges for the operation of inner tracking detectors. A possible solution is to use active silicon sensors, taking advantage of commercial CMOS technologies. Currently ATLAS R&D programme is qualifying a few commercial technologies in terms of suitability for this task. In this paper a prototype designed in one of them (LFoundry 150 nm process) will be discussed. The chip architecture ...

  1. Dosimetric characteristics of radiation fields on board Czechoslovak Airlines' aircraft as measured with different active and passive detectors

    Dosimetric characteristics on board Czechoslovak Airlines' aircraft (TU 154M; A310-300) were studied with different active and passive detectors (ionisation chamber RSS 112; scintillator based rate meter; GM counter based rate meter; neutron remmeter based on neutron moderation; thermoluminescence detectors, CR 39 track detectors and bubble-damage neutron detectors). Results obtained are analysed and discussed. It is estimated that the dose equivalent rates at altitudes of about 10 km are at least 3-4 μSv.h-1. Conclusions and recommendations for further studies and for radiation protection are given. (author)

  2. Alpha activity of 190 Pt isotope measured with CR-39 track detector

    A new method to measure alpha activity of long-lived radioisotopes is reported. The method consists basically in using CR-39 track detectors in close contact with thick samples of the radioelement to be investigated. Accordingly, a long-term exposure experiment has been performed using metallic sheets of natural platinum to measure alpha activity of platinum 190 isotope. The half-life of platinum 190 has been obtained in good agreement with two recent theoretical half-life predictions. (author). 21 refs., 3 figs., 2 tabs

  3. Characterization of thin p-on-p radiation detectors with active edges

    Peltola, T.; Wu, X.; Kalliopuska, J.; Granja, C.; Jakubek, J.; Jakubek, M.; Härkönen, J.; Gädda, A.

    2016-03-01

    Active edge p-on-p silicon pixel detectors with thickness of 100 μm were fabricated on 150 mm float zone silicon wafers at VTT. By combining measured results and TCAD simulations, a detailed study of electric field distributions and charge collection performances as a function of applied voltage in a p-on-p detector was carried out. A comparison with the results of a more conventional active edge p-on-n pixel sensor is presented. The results from 3D spatial mapping show that at pixel-to-edge distances less than 100 μm the sensitive volume is extended to the physical edge of the detector when the applied voltage is above full depletion. The results from a spectroscopic measurement demonstrate a good functionality of the edge pixels. The interpixel isolation above full depletion and the breakdown voltage were found to be equal to the p-on-n sensor while lower charge collection was observed in the p-on-p pixel sensor below 80 V. Simulations indicated this to be partly a result of a more favourable weighting field in the p-on-n sensor and partly of lower hole lifetimes in the p-bulk.

  4. Characterization of Thin p-on-p Radiation Detectors with Active Edges

    Peltola, T; Kalliopuska, J; Granja, C; Jakubek, J; Jakubek, M; Härkönen, J; Gädda, A

    2016-01-01

    Active edge p-on-p silicon pixel detectors with thickness of 100 $\\mu$m were fabricated on 150 mm Float zone silicon wafers at VTT. By combining measured results and TCAD simulations, a detailed study of electric field distributions and charge collection performances as a function of applied voltage in a p-on-p detector was carried out. A comparison with the results of a more conventional active edge p-on-n pixel sensor is presented. The results from 3D spatial mapping show that at pixel-to-edge distances less than 100 $\\mu$m the sensitive volume is extended to the physical edge of the detector when the applied voltage is above full depletion. The results from a spectroscopic measurement demonstrate a good functionality of the edge pixels. The interpixel isolation above full depletion and the breakdown voltage were found to be equal to the p-on-n sensor while lower charge collection was observed in the p-on-p pixel sensor below 80 V. Simulations indicated this to be partly a result of a more favourable weight...

  5. Measurement and analysis of high energy radiation through activation detectors. Application in dosimetry

    This work is concerned with the possibility of measurement and analysis of radiation fluences within objects of small volume submitted to a high energy proton beam. The first part, consecrated to the establishment of a method of analysis, comprises a detailed study of the radiation nature and energy spectra as well as of the various dosimetry methods. In order to select a group of detectors, high energy nuclear reactions were systematically studied and for some of them cross sections were measured or calculated: for example the cross section of the reaction 11B (p,n) 11C between 150 and 3000 MeV and of the reaction 34S (p,2pn) 32P between 50 and 3000 MeV. The second part is relative to the application of the fore-mentioned analysis to radiation within a tissue equivalent phantom irradiated by 3 GeV protons. This analysis is sufficiently detailed to allow the reconstitution of the absorbed doses, the dose equivalent and, contingent on a better knowledge of the dose due to heavy particles, the quality factors. It allowed also to follow the evolution of the various dosimetric data as a function of the depth inside the phantom and to verify calculations already done by other researchers. The comparison of the measured doses and the corresponding detector activities revealed the possibility that some detectors could give directly the absorbed dose, or even the dose equivalent, by a simple activity measurement. (author)

  6. Tragaldabas: a muon ground-based detector for the study of the solar activity; first observations

    José Blanco, Juan

    2016-04-01

    A new RPC-based cosmic ray detector, TRAGALDABAS (acronym of "TRAsGo for the AnaLysis of the nuclear matter Decay, the Atmosphere, the earth's B-field And the Solar activity") has been installed at the Univ. of Santiago de Compostela, Spain (N:42°52'34",W:8°33'37"). The detector, in its present layout, consists of three 1.8 m2 planes of three 1mm-gap glass RPCs. Each plane is readout with 120 pads with grounded guard electrodes between them to minimize the crosstalk noise. The main performances of the detectors are: an arrival time resolution of about ~300 ps, a tracking angular resolution below 3°, a detection efficiency close to 1, and a solid angle acceptance of ~5 srad. TRAGALDABAS will be able to monitor the cosmic ray low energy component strongly modulated by solar activity by mean the observation of secondary muons from the interaction between cosmic rays and atmospheric molecules. Its cadence and its angular resolution will allow to study in detail, small variations in cosmic ray anisotropy. These variations can be a key parameter to understand the effect of solar disturbances on the propagation of cosmic ray in the inner heliosphere and, maybe, provide a new tool for space weather analysis. In this work first TRAGALDABAS observations of solar events are shown

  7. Logarithmic InGaAs detectors with global shutter and active dark current reduction

    Ni, Yang; Arion, Bogdan; Bouvier, Christian; Noguier, Vincent

    2015-05-01

    In this paper, we present newly developed logarithmic InGaAs detectors with global shuttering and also an active dark current reduction technique to ensure ambient temperature operation without TEC for industrial applications. The newly released detectors come with both VGA (15um pitch) and QVGA (25um pitch) resolutions, giving the possibility to use lens less than 1-inch size. The logarithmic response is obtained by using solar-cell mode InGaAs photodiodes. The VGA and QVGA ROICs have 3 analog memories inside each pixel which permit, except the classic ITR, IWR and CDS modes, a new differential imaging mode which can be a useful feature in active imaging systems. The photodiode frontend circuit, in pure voltage mode, is made with non-inverting amplifier instead of CTIA. The reason of this choice is that the exposure time can be shortened without need of excessive power consumption as in CTIA front-end. We think that this arrangement associated with true CDS could match the noise performance of CTIA based one. VGA and QVGA ROICs have been designed and manufactured by using 0.18um 1P4M CMOS process. Both ROIC have been tested with success and match the design targets. The first batch of both detectors is under fabrication and will be presented during the conference.

  8. Measurement of the cosmogenic activation of germanium detectors in EDELWEISS-III

    Armengaud, E; Augier, C; Benoît, A; Bergé, L; Billard, J; Blümer, J; de Boissière, T; Broniatowski, A; Camus, P; Cazes, A; Chapellier, M; Charlieux, F; De Jésus, M; Dumoulin, L; Eitel, K; Foerster, N; Gascon, J; Giuliani, A; Gros, M; Hehn, L; Heuermann, G; Jin, Y; Juillard, A; Kéfélian, C; Kleifges, M; Kozlov, V; Kraus, H; Kudryavtsev, V A; Le-Sueur, H; Marnieros, S; Navick, X -F; Nones, C; Olivieri, E; Pari, P; Paul, B; Piro, M -C; Poda, D; Queguiner, E; Rozov, S; Sanglard, V; Schmidt, B; Scorza, S; Siebenborn, B; Tcherniakhovski, D; Vagneron, L; Weber, M; Yakushev, E

    2016-01-01

    We present a measurement of the cosmogenic activation in the germanium cryogenic detectors of the EDELWEISS III direct dark matter search experiment. The decay rates measured in detectors with different exposures to cosmic rays above ground are converted into production rates of different isotopes. The measured production rates in units of nuclei/kg/day are 82 $\\pm$ 21 for $^3$H, 2.8 $\\pm$ 0.6 for $^{49}$V, 4.6 $\\pm$ 0.7 for $^{55}$Fe, and 106 $\\pm$ 13 for $^{65}$Zn. These results are the most accurate for these isotopes. A lower limit on the production rate of $^{68}$Ge of 74 nuclei/kg/day is also presented. They are compared to model predictions present in literature and to estimates calculated with the ACTIVIA code.

  9. Performance of an improved thermal neutron activation detector for buried bulk explosives

    McFee, J.E., E-mail: jemcfee@gmail.com [Defence R and D Canada – Suffield, Medicine Hat (Canada); Faust, A.A. [Defence R and D Canada – Suffield, Medicine Hat (Canada); Andrews, H.R.; Clifford, E.T.H. [Bubble Technology Industries Inc., Chalk River (Canada); Mosquera, C.M. [Defence R and D Canada – Suffield, Medicine Hat (Canada)

    2013-06-01

    First generation thermal neutron activation (TNA) sensors, employing an isotopic source and NaI(Tl) gamma ray detectors, were deployed by Canadian Forces in 2002 as confirmation sensors on multi-sensor landmine detection systems. The second generation TNA detector is being developed with a number of improvements aimed at increasing sensitivity and facilitating ease of operation. Among these are an electronic neutron generator to increase sensitivity for deeper and horizontally displaced explosives; LaBr{sub 3}(Ce) scintillators, to improve time response and energy resolution; improved thermal and electronic stability; improved sensor head geometry to minimize spatial response nonuniformity; and more robust data processing. The sensor is described, with emphasis on the improvements. Experiments to characterize the performance of the second generation TNA in detecting buried landmines and improvised explosive devices (IEDs) hidden in culverts are described. Performance results, including comparisons between the performance of the first and second generation systems are presented.

  10. Stabilization of prompt gamma-ray neutron activation analysis (PGNAA) spectra from NaI detectors

    Metwally, W.A.; Gardner, R.P. E-mail: gardner@ncsu.edu

    2004-06-11

    NaI detectors are still used frequently in industrial Prompt Gamma-Ray Neutron Activation Analysis applications such as in bulk material analysis. They have the advantages of being efficient for high-energy gamma rays, being relatively rugged, and being able to be used without cooling. When using NaI detectors, and consequently photomultiplier tubes, the quality of the data can drastically deteriorate through gain and zero shifts that result in spectral smearing due to temperature and/or counting rate changes. A new offline approach is presented to stabilize the NaI spectral drift. The approach is not sensitive to the cause of the drift and takes into account the NaI and ADC non-linearities. Peak resolution is improved substantially when this approach is used in the presence of spectral drift.

  11. Stabilization of prompt gamma-ray neutron activation analysis (PGNAA) spectra from NaI detectors

    Metwally, W. A.; Gardner, R. P.

    2004-06-01

    NaI detectors are still used frequently in industrial Prompt Gamma-Ray Neutron Activation Analysis applications such as in bulk material analysis. They have the advantages of being efficient for high-energy gamma rays, being relatively rugged, and being able to be used without cooling. When using NaI detectors, and consequently photomultiplier tubes, the quality of the data can drastically deteriorate through gain and zero shifts that result in spectral smearing due to temperature and/or counting rate changes. A new offline approach is presented to stabilize the NaI spectral drift. The approach is not sensitive to the cause of the drift and takes into account the NaI and ADC non-linearities. Peak resolution is improved substantially when this approach is used in the presence of spectral drift.

  12. Exploration Of Activity Measurements And Equilibrium Checks For Sediment Dating Using Thick-Window Germanium Detectors

    Warner, Jacob A.; Fitzsimmons, Kathryn E.; Reynolds, Eva M.; Gladkis, Laura G.; Timmers, Heiko

    2011-06-01

    Activity measurements on sediment samples for trapped-charge geological dating using gamma-ray spectroscopy are an important verification of the field-site dose rate determination. Furthermore gamma-ray spectroscopy can check if the natural decay series are in secular equilibrium which is a crucial assumption in such dating. Typically the activities of leading members of the Thorium and Uranium decay series are measured, which requires Germanium detectors with thin windows and good energy resolution in order to effectively detect the associated low energy gamma-rays. Such equipment is not always readily available. The potential of conventional Germanium detectors with thick entrance window has been explored towards routine gamma-ray spectroscopy of sediment samples using higher energy gamma-rays. Alternative isotopes, such as Ac-228 and Pb-212 for the Thorium series, and Pa-234m, Ra-226 and Bi-214 for the Uranium series, have been measured in order to determine the mass-specific activity for the respective series and possibly provide a check of secular equilibrium. In addition to measurements of the K-40 activity, with the alternative approach, the activities of both decay series can be accurately determined. The secular equilibrium condition may be tested for the Thorium series. Measurement accuracy for Pa-234m is, however, not sufficient to permit also a reliable check of equilibrium for the Uranium series.

  13. Praseodymium activation detector for measuring bursts of 14 MeV neutrons

    A new, accurate, neutron activation detection scheme for measuring pulsed neutrons has been designed and tested. The detection system is sensitive to neutrons with energies above 10 MeV; importantly, it is insensitive to gamma radiation 141Pr, an element that has a single, naturally occurring isotope, a significant n,2n cross-section, and decays by positron emission that result in two coincident 511 keV photons. Neutron fluences are thus inferred by relating measured reaction product decay activity to fluence. Specific sample activity is measured using the sum-peak method to count gamma-ray coincidences from the annihilation of the positron decay products. The system was tested using 14 and 2.45 MeV neutron bursts produced by NSTec Dense Plasma Focus Laboratory fusion sources. Lead, copper, beryllium, and silver activation detectors were compared. The detection method allows measurement of 14 MeV neutron yield with a total error of ∼18%.

  14. Activity of CERN and LNF groups on large area GEM detectors

    Alfonsi, M; Brock, I; Cerioni, S; Croci, G; David, E; De Lucia, E; De Oliveira, R; De Robertis, G; Domenici, D; Duarte Pinto, S; Felici, G; Gatta, M; Jacewicz, M; Loddo, F; Morello, G; Pistilli, M; Ranieri, A; Ropelewski, L; Sauli, F; Schioppa, M; Van Stenis, M

    2010-01-01

    We report on the activity of CERN and INFN-LNF groups on the development of large area GEM detectors. The two groups work together within the RD51 Collaboration, to aim at the development of Micro-pattern Gas detectors technologies. The vast request for large area foils by the GEM community has driven a change in the manufacturing procedure by the TS-DEM-PMT laboratory, needed to overcome the previous size limitation of 450 x 450 mm2. Now a single-mask technology is used allowing foils to be made as large as 450 x 2000 mm2. The limitation in the short size, due to the definite width of the raw material, can be overcome by splicing more foils together. A 10 x 10 cm2 GEM detector with the new single-mask foil has been tested with X-rays and the results are shown. Possible future applications for large area GEM are the TOTEM experiment upgrade at CERN, and the KLOE-2 experiment at the Dafne Φ-factory in Frascati.

  15. Activity of CERN and LNF groups on large area GEM detectors

    Alfonsi, M. [CERN, Geneva (Switzerland); Bencivenni, G. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Brock, I. [Physikalisches Institute der Universitat Bonn, Bonn (Germany); Cerioni, S. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Croci, G.; David, E. [CERN, Geneva (Switzerland); De Lucia, E. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); De Oliveira, R. [CERN, Geneva (Switzerland); De Robertis, G. [Sezione INFN di Bari, Bari (Italy); Domenici, D., E-mail: Danilo.Domenici@lnf.infn.i [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Duarte Pinto, S. [CERN, Geneva (Switzerland); Felici, G.; Gatta, M.; Jacewicz, M. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Loddo, F. [Sezione INFN di Bari, Bari (Italy); Morello, G. [Dipeartimento di Fisica Universita della Calabria e INFN, Cosenza (Italy); Pistilli, M. [Laboratori Nazionali di Frascati dell' INFN, Frascati (Italy); Ranieri, A. [Sezione INFN di Bari, Bari (Italy); Ropelewski, L. [CERN, Geneva (Switzerland); Sauli, F. [TERA Foundation, Novara (Italy)

    2010-05-21

    We report on the activity of CERN and INFN-LNF groups on the development of large area GEM detectors. The two groups work together within the RD51 Collaboration, to aim at the development of Micro-pattern Gas detectors technologies. The vast request for large area foils by the GEM community has driven a change in the manufacturing procedure by the TS-DEM-PMT laboratory, needed to overcome the previous size limitation of 450x450mm{sup 2}. Now a single-mask technology is used allowing foils to be made as large as 450x2000mm{sup 2}. The limitation in the short size, due to the definite width of the raw material, can be overcome by splicing more foils together. A 10x10cm{sup 2} GEM detector with the new single-mask foil has been tested with X-rays and the results are shown. Possible future applications for large area GEM are the TOTEM experiment upgrade at CERN, and the KLOE-2 experiment at the Dafne {Phi}-factory in Frascati.

  16. Activity of CERN and LNF groups on large area GEM detectors

    We report on the activity of CERN and INFN-LNF groups on the development of large area GEM detectors. The two groups work together within the RD51 Collaboration, to aim at the development of Micro-pattern Gas detectors technologies. The vast request for large area foils by the GEM community has driven a change in the manufacturing procedure by the TS-DEM-PMT laboratory, needed to overcome the previous size limitation of 450x450mm2. Now a single-mask technology is used allowing foils to be made as large as 450x2000mm2. The limitation in the short size, due to the definite width of the raw material, can be overcome by splicing more foils together. A 10x10cm2 GEM detector with the new single-mask foil has been tested with X-rays and the results are shown. Possible future applications for large area GEM are the TOTEM experiment upgrade at CERN, and the KLOE-2 experiment at the Dafne Φ-factory in Frascati.

  17. CMOS Active Pixel Sensors as energy-range detectors for proton Computed Tomography

    Since the first proof of concept in the early 70s, a number of technologies has been proposed to perform proton CT (pCT), as a means of mapping tissue stopping power for accurate treatment planning in proton therapy. Previous prototypes of energy-range detectors for pCT have been mainly based on the use of scintillator-based calorimeters, to measure proton residual energy after passing through the patient. However, such an approach is limited by the need for only a single proton passing through the energy-range detector in a read-out cycle. A novel approach to this problem could be the use of pixelated detectors, where the independent read-out of each pixel allows to measure simultaneously the residual energy of a number of protons in the same read-out cycle, facilitating a faster and more efficient pCT scan. This paper investigates the suitability of CMOS Active Pixel Sensors (APSs) to track individual protons as they go through a number of CMOS layers, forming an energy-range telescope. Measurements performed at the iThemba Laboratories will be presented and analysed in terms of correlation, to confirm capability of proton tracking for CMOS APSs

  18. CMOS Active Pixel Sensors as energy-range detectors for proton Computed Tomography

    Esposito, M.; Anaxagoras, T.; Evans, P. M.; Green, S.; Manolopoulos, S.; Nieto-Camero, J.; Parker, D. J.; Poludniowski, G.; Price, T.; Waltham, C.; Allinson, N. M.

    2015-06-01

    Since the first proof of concept in the early 70s, a number of technologies has been proposed to perform proton CT (pCT), as a means of mapping tissue stopping power for accurate treatment planning in proton therapy. Previous prototypes of energy-range detectors for pCT have been mainly based on the use of scintillator-based calorimeters, to measure proton residual energy after passing through the patient. However, such an approach is limited by the need for only a single proton passing through the energy-range detector in a read-out cycle. A novel approach to this problem could be the use of pixelated detectors, where the independent read-out of each pixel allows to measure simultaneously the residual energy of a number of protons in the same read-out cycle, facilitating a faster and more efficient pCT scan. This paper investigates the suitability of CMOS Active Pixel Sensors (APSs) to track individual protons as they go through a number of CMOS layers, forming an energy-range telescope. Measurements performed at the iThemba Laboratories will be presented and analysed in terms of correlation, to confirm capability of proton tracking for CMOS APSs.

  19. A proposed STAR microvertex detector using Active Pixel Sensors with some relevant studies on APS performance

    A vertex detector that can measure particles with charm or bottom quarks would dramatically expand the physics capability of the STAR detector at RHIC. To accomplish this, we are proposing to build the Heavy Flavor Tracker (HFT) using 2x2 cm Active Pixels Sensors (APS). Ten of these APS chips will be arranged on a ladder (0.28% of a radiation length) at radii of 1.5 and at 5.0 cm. We have examined several properties of APS chips, so that we can characterize the performance of this detector. Using 1.5 GeV/c electrons, we have measured the charge collected and compared it to the expected charge. To achieve high efficiency, we have considered two different cluster finding algorithms and found that the choice of algorithm is dependent on noise level. We have demonstrated that a Scanning Electron Microscope can probe properties of an APS chip. In particular, we studied several position resolution algorithms. Finally, we studied the properties of pixel pitches from 5 to 30 μm

  20. Thick activation detectors for neutron spectrometry using different unfolding methods: sensitivity analysis and dose calculation

    Medkour Ishak-Boushaki, Ghania, E-mail: gmedkour@yahoo.com [Laboratoire SNIRM-Faculte de Physique, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia BabEzzouar, Algiers (Algeria); Boukeffoussa, Khelifa [Laboratoire SNIRM-Faculte de Physique, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia BabEzzouar, Algiers (Algeria); Idiri, Zahir [Centre de Recherche Nucleaire d' Alger, 02 Boulevard Frantz-Fanon, BP 399, Algiers (Algeria); Allab, Malika [Laboratoire SNIRM-Faculte de Physique, Universite des Sciences et de la Technologie Houari Boumediene, BP 32 El-Alia BabEzzouar, Algiers (Algeria)

    2012-03-15

    This paper discusses the use of threshold detectors of extended sizes for low intensity neutron fields' characterization. The detectors were tested by the measurement of the neutron spectrum of an {sup 241}Am-Be source. Integral quantities characterizing the neutron field, required for radiological protection, have been derived by unfolding the measured data. A good agreement is achieved between the obtained results and those deduced using Bonner spheres. In addition, a sensitivity analysis of the results to the deconvolution procedure is given. - Highlights: Black-Right-Pointing-Pointer Low intensity neutron fields' characterization using thick threshold detectors. Black-Right-Pointing-Pointer Low activity {sup 241}Am-Be neutron source spectrum measurement. Black-Right-Pointing-Pointer Integral quantities required for radiological protection have been derived. Black-Right-Pointing-Pointer The results are in good agreement with those deduced using Bonner spheres. Black-Right-Pointing-Pointer The results are not very sensitive to the chosen deconvolution procedure.

  1. Performance of hybrid photon detector prototypes with 80% active area for the RICH counters of LHCb

    Albrecht, E; Barber, G J; Bibby, J H; Campbell, M; Duane, A; Gys, Thierry; Montenegro, J; Piedigrossi, D; Schomaker, R; Snoeys, W; Wotton, S A; Wyllie, Ken H

    2000-01-01

    We report on the ongoing work towards a hybrid photon detector with integrated Si pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN. The photon detector is based on an electrostatically focussed image intensifier tube geometry where the image is de-magnified by a factor of ~5. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The performance of full-scale prototypes equipped with 61-pixel anodes and external analogue readout is presented. The average signal-to-noise ratio is ~11 with a peaking time of 1.2 mu s. The tube active-to-total surface ratio is 81.7%, which meets the LHCb requirements. The spatial precision is measured to be better than 90 mu m. A cluster of three such tubes has been installed in the LHCb RICH 1 prototype where Cherenkov gas rings have been successfully detected. Progress towards the encapsulation of new pixel electronics into a tube is also reported. In pa...

  2. Prototype Active Silicon Sensor in 150 nm HR-CMOS Technology for ATLAS Inner Detector Upgrade

    Rymaszewski, Piotr; Breugnon, Patrick; Godiot, Stépahnie; Gonella, Laura; Hemperek, Tomasz; Hirono, Toko; Hügging, Fabian; Krüger, Hans; Liu, Jian; Pangaud, Patrick; Peric, Ivan; Rozanov, Alexandre; Wang, Anqing; Wermes, Norbert

    2016-01-01

    The LHC Phase-II upgrade will lead to a significant increase in luminosity, which in turn will bring new challenges for the operation of inner tracking detectors. A possible solution is to use active silicon sensors, taking advantage of commercial CMOS technologies. Currently ATLAS R&D programme is qualifying a few commercial technologies in terms of suitability for this task. In this paper a prototype designed in one of them (LFoundry 150 nm process) will be discussed. The chip architecture will be described, including different pixel types incorporated into the design, followed by simulation and measurement results.

  3. Prototype Active Silicon Sensor in 150 nm HR-CMOS technology for ATLAS Inner Detector Upgrade

    Rymaszewski, P.; Barbero, M.; Breugnon, P.; Godiot, S.; Gonella, L.; Hemperek, T.; Hirono, T.; Hügging, F.; Krüger, H.; Liu, J.; Pangaud, P.; Peric, I.; Rozanov, A.; Wang, A.; Wermes, N.

    2016-02-01

    The LHC Phase-II upgrade will lead to a significant increase in luminosity, which in turn will bring new challenges for the operation of inner tracking detectors. A possible solution is to use active silicon sensors, taking advantage of commercial CMOS technologies. Currently ATLAS R&D programme is qualifying a few commercial technologies in terms of suitability for this task. In this paper a prototype designed in one of them (LFoundry 150 nm process) will be discussed. The chip architecture will be described, including different pixel types incorporated into the design, followed by simulation and measurement results.

  4. History of the bubble chamber and related active- and internal-target nuclear tracking detectors

    Donald Glaser, 1960 Nobel laureate in Physics, recently passed away (2013), as have many of his colleagues who were involved with the early development of bubble chambers at the University of Michigan. In this paper I will review those early years and the subsequent wide-spread application of active-target (AT) bubble chambers that dominated high-energy physics (HEP) research for over thirty years. Some of the related, but more modern nuclear tracking detectors being used in HEP, neutrino astrophysics and dark-matter searches also will be discussed

  5. Transmutation detectors

    Viererbl, L.; Lahodová, Z.; Klupák, V.; Sus, F.; Kučera, Jan; Kůs, P.; Marek, M.

    2011-01-01

    Roč. 632, č. 1 (2011), s. 109-111. ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10480505 Keywords : Transmutation detector * Activation method * Neutron detector * Neutron fluence Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.207, year: 2011

  6. Evaluation of radon measuring technique using passive detector activated carbon; Avaliacao da tecnica de medicao do radonio utilizando detector passivo com carvao ativado

    Ferreira, Paulo Roberto Rocha; Lessa, Edmilson de Lima; Oliveira, Evaldo Paulo de, E-mail: epoliveira@aluno.ird.gov.br [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Radioprotecao Ambiental e Ocupacional

    2014-07-01

    This study aims to evaluate the efficiency of measuring the radioactive gas Radon ({sup 222} Rn) with passive detector activated carbon. Alpha Guard, exposure chamber, air sampler, default font Radio, calibrator flow, flow adjuster, ducts drivers: For this, various equipment to make the measurement system as were used. An assembly of such equipment, with specific sequence was used allowing for more efficient exposure of passive detectors Radon gas. Twenty samples were heated to remove moisture and then stored in desiccator until the experiment were made. The exhibition was held passive dosimeters being removed from the chamber, and one hour after, subjected to analysis by gamma spectrometry in germanium (HPGe) for an hour. Subsequently, other measurements were made at scheduled times and sequential for one hour. The results were presented in report form and spectra, measures and graphs generated by Alpha Guard were also extracted. Finally we calculated the efficiency of the passive meter activated carbon. (author)

  7. Silver activated counter detector for measurements of high intensity fast neutron burst

    In fusion facilities, such as Z pinch, plasma focus or laser driven experiments, fast neutrons are produced in the form of a burst of radiation. For these kinds of sources, moderation of the neutron energy and silver activation is one of the most common techniques for measurement of the neutron yield. In the recent years, the study of this detection system has been revisited in order to improve the calibration methodologies, and to study the effects of moderator geometry for measurements in low intensity burst neutron sources. In this work, the design, construction and characterization of a silver activated neutron counter for measurements in high intensity neutron burst sources are reported. For such sources (Y4π > 109 n/burst), the effects of moderator geometry, as well as, the systematic effects introduced in the measurement by dead time, after irradiation of the detector by a burst of neutrons, are discussed and included in the measurement methodology

  8. Micro-Fabricated Solid-State Radiation Detectors for Active Personal Dosimetry

    Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Chen, Liang-Yu

    2007-01-01

    Active radiation dosimetry is important to human health and equipment functionality for space applications outside the protective environment of a space station or vehicle. This is especially true for long duration missions to the moon, where the lack of a magnetic field offers no protection from space radiation to those on extravehicular activities. In order to improve functionality, durability and reliability of radiation dosimeters for future NASA lunar missions, single crystal silicon carbide devices and scintillating fiber detectors are currently being investigated for applications in advanced extravehicular systems. For many years, NASA Glenn Research Center has led significant efforts in silicon carbide semiconductor technology research and instrumentation research for sensor applications under extreme conditions. This report summarizes the technical progress and accomplishments toward characterization of radiation-sensing components for the recommendation of their fitness for advanced dosimetry development.

  9. Activation of Organic Photovoltaic Light Detectors Using Bend Leakage from Optical Fibers.

    Griffith, Matthew J; Willis, Matthew S; Kumar, Pankaj; Holdsworth, John L; Bezuidenhout, Henco; Zhou, Xiaojing; Belcher, Warwick; Dastoor, Paul C

    2016-03-30

    This work investigates the detection and subsequent utilization of leaked light from bends in a silica optical fiber using organic photovoltaic detectors. The optic power lost by single mode and multimode silica optical fibers was calibrated for bend radii between 1 and 7 mm for 532 and 633 nm light, exhibiting excellent agreement with previous theoretical solutions. The spatial location of maximum power leakage on the exterior of the fiber was found to exist in the same plane as the fiber, with a 10° offset from the normal. Two different organic photovoltaic detectors fabricated using a poly(3-hexylthiophene):indene-C60-bisadduct donor-acceptor blend cast from chloroform and chlorobenzene were fabricated to detect the leaked light. The two detectors exhibited different photovoltaic performances, predominantly due to different active layer thicknesses. Both devices showed sensitivity to leakage light, exhibiting voltages between 200 and 300 mV in response to leaked light from the fiber. The temporal responses of the devices were observed to differ, with a rise time from 10% to 90% of maximum voltage of 1430 μs for the chlorobenzene device, and a corresponding rise time of 490 μs for the higher performing chloroform device. The two OPVs were used to simultaneously detect leaked light from induced bends in the optical fiber, with the differing temporal profiles employed to create a unique time-correlated detection signal with enhanced security. The delay between detection of each OPV voltage could be systematically varied, allowing for either a programmable and secure single detection signal or triggering of multiple events with variable time resolution. The results reported in this study present exciting avenues toward the deployment of this simple and noninvasive optical detection system in a range of different applications. PMID:26891938

  10. Determination of self-shielding factor of activation detectors in neutron flux and spectrum measurements in RSG-Gas reactor

    Determination of self-shielding factor and cadmium ration of foil and cylindrical probe have been done by measurement and calculation. Self-shielding factor was determined by dividing the activity of detector with its Al-alloy. Theoretically, self-shielding factor can be determined by numerical solution of two-dimensional integral equations in FORTRAN. For gold foil and wire, the calculation result are quite close to the measurement. The relative difference between calculation and measurement of activity, self-shielding factor and cadmium ratio are respectively less than 11%, 9% and 4%. It is therefore, the calculation program can be used for calculation of other kinds of activation detectors. The application in neutron flux measurement gives a better result especially for epithermal flux. For neutron spectrum measurement, self-shielding correction can avoid resonance peaks in epithermal region due to absorption by activation detectors. (author)

  11. A new single crystal diamond dosimeter for small beam: comparison with different commercial active detectors

    Recent developments of new therapy techniques using small photon beams, such as stereotactic radiotherapy, require suitable detectors to determine the delivered dose with a high accuracy. The dosimeter has to be as close as possible to tissue equivalence and to exhibit a small detection volume compared to the size of the irradiation field, because of the lack of lateral electronic equilibrium in small beam. Characteristics of single crystal diamond (tissue equivalent material Z = 6, high density) make it an ideal candidate to fulfil most of small beam dosimetry requirements. A commercially available Element Six electronic grade synthetic diamond was used to develop a single crystal diamond dosimeter (SCDDo) with a small detection volume (0.165 mm3). Long term stability was studied by irradiating the SCDDo in a 60Co beam over 14 h. A good stability (deviation less than ± 0.1%) was observed. Repeatability, dose linearity, dose rate dependence and energy dependence were studied in a 10 × 10 cm2 beam produced by a Varian Clinac 2100 C linear accelerator. SCDDo lateral dose profile, depth dose curve and output factor (OF) measurements were performed for small photon beams with a micro multileaf collimator m3 (BrainLab) attached to the linac. This study is focused on the comparison of SCDDo measurements to those obtained with different commercially available active detectors: an unshielded silicon diode (PTW 60017), a shielded silicon diode (Sun Nuclear EDGE), a PinPoint ionization chamber (PTW 31014) and two natural diamond detectors (PTW 60003). SCDDo presents an excellent spatial resolution for dose profile measurements, due to its small detection volume. Low energy dependence (variation of 1.2% between 6 and 18 MV photon beam) and low dose rate dependence of the SCDDo (variation of 1% between 0.53 and 2.64 Gy min−1) are obtained, explaining the good agreement between the SCDDo and the efficient unshielded diode (PTW 60017) in depth dose curve measurements. For

  12. Radiation-hard active CMOS pixel sensors for HL-LHC detector upgrades

    Backhaus, Malte

    2015-02-01

    The luminosity of the Large Hadron Collider (LHC) will be increased during the Long Shutdown of 2022 and 2023 (LS3) in order to increase the sensitivity of its experiments. A completely new inner detector for the ATLAS experiment needs to be developed to withstand the extremely harsh environment of the upgraded, so-called High-Luminosity LHC (HL-LHC). High radiation hardness as well as granularity is mandatory to cope with the requirements in terms of radiation damage as well as particle occupancy. A new silicon detector concept that uses commercial high voltage and/or high resistivity full complementary metal-oxide-semiconductor (CMOS) processes as active sensor for pixel and/or strip layers has risen high attention, because it potentially provides high radiation hardness and granularity and at the same time reduced price due to the commercial processing and possibly relaxed requirements for the hybridization technique. Results on the first prototypes characterized in a variety of laboratory as well as test beam environments are presented.

  13. Estimation of radioactive noble gas activity in FBTR. A simple method of Calibration of HPGe detector

    In the plant health physics surveillance programme, analysis and activity estimation of radioactive gaseous species released through stack are essential from the point of view of protecting environment and public. Reactor cover gas analysis is used for detection of fuel-clad failure and the localization of the failed fuel in the core by quantifying fission product noble gases (FPNGs). Gamma spectrometry is the most established method used for the identification and quantification of radioactive gases. For proper estimation of gaseous radioisotopes, the calibration procedure shall be an accurate one and also it is preferable if the experimental findings are in agreement with the theoretically estimated ones. Getting the gaseous calibration standard sources is practically not easy because the half-lives of noble gases are very less. To overcome this difficulty, a simple experimental method of determination of the sensitivity factors covering an energy up to 1.5 MeV for the HPGe detector based γ-ray spectrometer is developed. In place of gaseous isotope standard, standard aqueous salt solutions containing 152Eu, 133Ba, 60Co, 22Na and 137Cs are used for calibration. The activity distribution profile is uniform in both aqueous and gaseous medium; however, the self-absorption by the aqueous medium needs to be taken into account while determining the sensitivity factors for various energies of gas. These self absorption factors in aqueous medium are calculated using the MCNP code and are applied to determine the sensitivity factors for gaseous medium. Calibration curve for a one-litre sample bottle kept on the top of a coaxial vertical HPGe detector is determined experimentally, Experimental values are compared with values computed by MCNP and these are in close agreement. Activity of radioactive noble gases present in the cover gas of fast breeder test reactor (FBTR) is estimated by using this method. (author)

  14. Germanium detectors for nuclear spectroscopy: Current research and development activity at LNL

    Napoli, D. R.; Maggioni, G.; Carturan, S.; Eberth, J.; Gelain, M.; Grimaldi, M. G.; Tatí, S.; Riccetto, S.; Mea, G. Della

    2016-07-01

    High-purity Germanium (HPGe) detectors have reached an unprecedented level of sophistication and are still the best solution for high-resolution gamma spectroscopy. In the present work, we will show the results of the characterization of new surface treatments for the production of these detectors, studied in the framework of our multidisciplinary research program in HPGe detector technologies.

  15. Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors.

    Jungmann, Julia H; Heeren, Ron M A

    2013-01-15

    Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and high mass detectors for mass spectrometry (imaging) are treated. State-of-the-art detection systems for multi-dimensional ion, electron and photon detection are highlighted. Their application and performance in three different imaging modes--integrated, selected and spectral image detection--are described. Electro-optical and microchannel-plate-based systems are contrasted. The analytical capabilities of solid-state pixel detectors--both charge coupled device (CCD) and complementary metal oxide semiconductor (CMOS) chips--are introduced. The Medipix/Timepix detector family is described as an example of a CMOS hybrid active pixel sensor. Alternative imaging methods for particle detection and their potential for future applications are investigated. PMID:23239313

  16. A Needle-Type p-i-n Junction Semiconductor Detector for In-Vivo Measurement of Beta Tracer Activity

    A miniature detector probe has been developed for in-vivo detection of beta tracer activity. A lithium-drifted p-i-n detector shaped as a cylinder 0.9 mm in diameter and 3 mm long acts as the sensing element. The detector is encased in a stainless steel tube 50 mm long, fastened to a holder fitted with a miniature coaxial contact. The free end of the tube has a syringe-like, entirely tight tip. The steel tube has an outer diameter of 1.4 mm except for 10 mm at the free end where the outer diameter is 1.1 mm corresponding to a wall thickness of 005 mm. The detector is placed in the 1.1 mm part of the tube. The construction and the properties of the probe are described

  17. Active Target detectors for studies with exotic beams: Present and next future

    Mittig, W.; Beceiro-Novo, S.; Fritsch, A.; Abu-Nimeh, F.; Bazin, D.; Ahn, T.; Lynch, W. G.; Montes, F.; Shore, A.; Suzuki, D.; Usher, N.; Yurkon, J.; Kolata, J. J.; Howard, A.; Roberts, A. L.; Tang, X. D.; Becchetti, F. D.

    2015-06-01

    Reaccelerated radioactive beams near the Coulomb barrier, which are starting to be available from the ReA3 accelerator at NSCL and in next future at FRIB, will open up new opportunities for the study of nuclear structure near the drip lines. Efficient measurement techniques must be developed to compensate for the limited intensity of the most exotic beams. The Active-Target Time Projection Chamber (AT-TPC) constructed at MSU solves this problem by providing the increased luminosity of a thick target while maintaining a good energy resolution by tracking the reaction vertex over an essentially 4 π solid angle. The AT-TPC and similar detectors allow us to take full advantage of the radioactive ion beams at present and future nuclear physics facilities to explore the frontier of rare isotopes.

  18. Active Detectors for Plasma Soft X-Ray Detection at PALS

    C. Granja

    2010-01-01

    Full Text Available This paper summarizes the work carried out for an experimental study of low-energy nuclear excitation by laser-produced plasma at the PALS Prague laser facility. We describe the adaptation and shielding of single-quantum active radiation detectors developed at IEAP CTU Prague to facilitate their operation inside the laser interaction chamber in the vicinity of the plasma target. The goal of this effort is direct real-time single-quantum detection of plasma soft X-ray radiation with energy above a few keV and subsequent identification of the decay of the excited nuclear states via low-energy gamma rays in a highly radiative environment with strong electromagnetic interference.

  19. Praseodymium activation detector for measuring bursts of 14 MeV neutrons

    Meehan, Tim, E-mail: meehanbt@nv.doe.go [National Security Technologies, LLC, P.O. Box 98521, North Las Vegas, NV 89030 (United States); Hagen, E.C. [National Security Technologies, LLC, P.O. Box 98521, North Las Vegas, NV 89030 (United States); Ruiz, C.L.; Cooper, G.W. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)

    2010-08-21

    A new, accurate, neutron activation detection scheme for measuring pulsed neutrons has been designed and tested. The detection system is sensitive to neutrons with energies above 10 MeV; importantly, it is insensitive to gamma radiation <10 MeV and to lower-energy (e.g., fission and thermal) neutrons. It is based upon the use of {sup 141}Pr, an element that has a single, naturally occurring isotope, a significant n,2n cross-section, and decays by positron emission that result in two coincident 511 keV photons. Neutron fluences are thus inferred by relating measured reaction product decay activity to fluence. Specific sample activity is measured using the sum-peak method to count gamma-ray coincidences from the annihilation of the positron decay products. The system was tested using 14 and 2.45 MeV neutron bursts produced by NSTec Dense Plasma Focus Laboratory fusion sources. Lead, copper, beryllium, and silver activation detectors were compared. The detection method allows measurement of 14 MeV neutron yield with a total error of {approx}18%.

  20. A study of the active thermal control for the high energy detector on the HXMT%A study of the active thermal control for the high energy detector on the HXMT

    张翼飞; 康士秀; 宋黎明; 李延国; 吴伯冰; 张永杰; 董永伟; 孙建超; 赵冬华; 邢闻; 柴军营

    2011-01-01

    A thermal control system (TCS) based on the resistance heating method is designed for the High Energy Detector (HED) on the Hard X-ray Modulation Telescope (HXMT). The ground-based experiments of the active thermal control for the HED with the TCS are per

  1. The Dexela 2923 CMOS X-ray detector: A flat panel detector based on CMOS active pixel sensors for medical imaging applications

    Complementary metal-oxide-semiconductors (CMOS) active pixel sensors (APS) have been introduced recently in many scientific applications. This work reports on the performance (in terms of signal and noise transfer) of an X-ray detector that uses a novel CMOS APS which was developed for medical X-ray imaging applications. For a full evaluation of the detector's performance, electro-optical and X-ray characterizations were carried out. The former included measuring read noise, full well capacity and dynamic range. The latter, which included measuring X-ray sensitivity, presampling modulation transfer function (pMTF), noise power spectrum (NPS) and the resulting detective quantum efficiency (DQE), was assessed under three beam qualities (28 kV, 50 kV (RQA3) and 70 kV (RQA5) using W/Al) all in accordance with the IEC standard. The detector features an in-pixel option for switching the full well capacity between two distinct modes, high full well (HFW) and low full well (LFW). Two structured CsI:Tl scintillators of different thickness (a “thin” one for high resolution and a thicker one for high light efficiency) were optically coupled to the sensor array to optimize the performance of the system for different medical applications. The electro-optical performance evaluation of the sensor results in relatively high read noise (∼360 e−), high full well capacity (∼1.5×106 e−) and wide dynamic range (∼73 dB) under HFW mode operation. When the LFW mode is used, the read noise is lower (∼165) at the expense of a reduced full well capacity (∼0.5×106 e−) and dynamic range (∼69 dB). The maximum DQE values at low frequencies (i.e. 0.5 lp/mm) are high for both HFW (0.69 for 28 kV, 0.71 for 50 kV and 0.75 for 70 kV) and LFW (0.69 for 28 kV and 0.7 for 50 kV) modes. The X-ray performance of the studied detector compares well to that of other mammography and general radiography systems, obtained under similar experimental conditions. This demonstrates the

  2. Design and Test of an Event Detector for the ReflectoActive Seals System

    Stinson, Brad J [ORNL

    2006-05-01

    The purpose of this thesis was to research, design, develop and test a novel instrument for detecting fiber optic loop continuity and spatially locating fiber optic breaches. The work is for an active seal system called ReflectoActive Seals whose purpose is to provide real time container tamper indication. A Field Programmable Gate Array was used to implement a loop continuity detector and a spatial breach locator based on a high acquisition speed single photon counting optical time domain reflectometer. Communication and other control features were added in order to create a usable instrument that met defined requirements. A host graphical user interface was developed to illustrate system use and performance. The resulting device meets performance specifications by exhibiting a dynamic range of 27dB and a spatial resolution of 1.5 ft. The communication scheme used expands installation options and allows the device to communicate to a central host via existing Local Area Networks and/or the Internet.

  3. Characterization of Depleted Monolithic Active Pixel detectors implemented with a high-resistive CMOS technology

    Kishishita, T.; Hemperek, T.; Rymaszewski, P.; Hirono, T.; Krüger, H.; Wermes, N.

    2016-07-01

    We present the recent development of DMAPS (Depleted Monolithic Active Pixel Sensor), implemented with a Toshiba 130 nm CMOS process. Unlike in the case of standard MAPS technologies which are based on an epi-layer, this process provides a high-resistive substrate that enables larger signal and faster charge collection by drift in a 50 - 300 μm thick depleted layer. Since this process also enables the use of deep n-wells to isolate the collection electrodes from the thin active device layer, NMOS and PMOS transistors are available for the readout electronics in each pixel cell. In order to characterize the technology, we implemented a simple three transistor readout with a variety of pixel pitches and input FET sizes. This layout variety gives us a clue on sensor characteristics for future optimization, such as the input detector capacitance or leakage current. In the initial measurement, the radiation spectra were obtained from 55Fe with an energy resolution of 770 eV (FWHM) and 90Sr with the MVP of 4165 e-.

  4. Active pixels of transverse field detector based on a charge preamplifier

    Langfelder, G.; Buffa, C.; Longoni, A. F.; Pelamatti, A.; Zaraga, F.

    2012-01-01

    The Transverse Field Detector (TFD), a filter-less and tunable color sensitive pixel, is based on the generation of specific electric field configurations within a depleted Silicon volume. Each field configuration determines a set of three or more spectral responses that can be used for direct color acquisition at each pixel position. In order to avoid unpredictable changes of the electric field configuration during the single image capture, a specific active pixel (AP) has been designed. In this AP the dark- and photo-generated charge is not integrated directly on the junction capacitance, but, for each color, it is integrated on the feedback capacitance of a single-transistor charge pre-amplifier. The AP further includes a bias transistor, a reset transistor and a follower. In this work the design of such a pixel is discussed and the experimental results obtained on a 2x2 matrix of these active pixels are analyzed in terms of spectral response, linearity, noise, dynamic range and repeatability.

  5. Design and Test of an Event Detector and Locator for the ReflectoActive Seals System

    Stinson, Brad J [ORNL

    2006-06-01

    The purpose of this work was to research, design, develop and test a novel instrument for detecting fiber optic loop continuity and spatially locating fiber optic breaches. The work is for an active seal system called ReflectoActive{trademark} Seals whose purpose is to provide real time container tamper indication. A Field Programmable Gate Array was used to implement a loop continuity detector and a spatial breach locator based on a high acquisition speed single photon counting optical time domain reflectometer. Communication and other control features were added in order to create a usable instrument that met defined requirements. A host graphical user interface was developed to illustrate system use and performance. The resulting device meets performance specifications by exhibiting a dynamic range of 27dB and a spatial resolution of 1.5 ft. The communication scheme used expands installation options and allows the device to communicate to a central host via existing Local Area Networks and/or the Internet.

  6. Design and Test of an Event Detector and Locator for the ReflectoActive Seals System

    The purpose of this work was to research, design, develop and test a novel instrument for detecting fiber optic loop continuity and spatially locating fiber optic breaches. The work is for an active seal system called ReflectoActive(trademark) Seals whose purpose is to provide real time container tamper indication. A Field Programmable Gate Array was used to implement a loop continuity detector and a spatial breach locator based on a high acquisition speed single photon counting optical time domain reflectometer. Communication and other control features were added in order to create a usable instrument that met defined requirements. A host graphical user interface was developed to illustrate system use and performance. The resulting device meets performance specifications by exhibiting a dynamic range of 27dB and a spatial resolution of 1.5 ft. The communication scheme used expands installation options and allows the device to communicate to a central host via existing Local Area Networks and/or the Internet.

  7. Voice Activity Detector of Wake-Up-Word Speech Recognition System Design on FPGA

    Veton Z. Këpuska

    2014-12-01

    Full Text Available A typical speech recognition system is push-to-talk operated that requires activation. However for those who use hands-busy applications, movement may by restricted or impossible. One alternative is to use Speech-Only Interface. The proposed method that is called Wake-Up-Word Speech Recognition (WUW-SR that utilizes speech only interface. A WUW-SR system would allow the user to activate systems (Cell phone, Computer, etc. with only speech commands instead of manual activation. The trend in WUW-SR hardware design is towards implementing a complete system on a single chip intended for various applications. This paper presents an experimental FPGA design and implementation of a novel architecture of a real time feature extraction processor that includes: Voice Activity Detector (VAD, and features extraction, MFCC, LPC, and ENH_MFCC. In the WUW-SR system, the recognizer front-end with VAD is located at the terminal which is typically connected over a data network(e.g., serverfor remote back-end recognition. VAD is responsible for segmenting the signal into speech-like and non-speech-like segments. For any given frame VAD reports one of two possible states: VAD_ON or VAD_OFF. The back-end is then responsible to score the features that are being segmented during VAD_ON stage. The most important characteristic of the presented design is that it should guarantee virtually 100% correct rejection for non-WUW (out of vocabulary words - OOV while maintaining correct acceptance rate of 99.9% or higher (in vocabulary words - INV. This requirement sets apart WUW-SR from other speech recognition tasks because no existing system can guarantee 100% reliability by any measure.

  8. Measurement of nuclear activity with Ge detectors and its uncertainty; Medicion de actividad nuclear con detectores de Ge y su incertidumbre

    Cortes P, C.A

    1999-07-01

    The objective of this work is to analyse the influence magnitudes which affect the activity measurement of gamma transmitter isolated radioactive sources. They prepared by means of the gravimetric method, as well as, determining the uncertainty of such measurement when this is carried out with a gamma spectrometer system with a germanium detector. This work is developed in five chapters: In the first one, named Basic principles it is made a brief description about the meaning of the word Measurement and its implications and the necessaries concepts are presented which are used in this work. In the second chapter it is exposed the gravimetric method used for the manufacture of the gamma transmitter isolated radioactive sources, it is tackled the problem to determine the main influence magnitudes which affect in the measurement of their activity and the respective correction factors and their uncertainties are deduced. The third chapter describes the gamma spectrometry system which is used in this work for the measurement of the activity of isolated sources and also its performance and experimental arrangement that it is used. In the fourth chapter are applied the three previous items with the object of determining the uncertainty which would be obtained in the measurement of an isolated radioactive source elaborated with the gravimetric method in the experimental conditions less favourable predicted above the obtained results from the chapter two. The conclusions are presented in the fifth chapter and they are applied to establish the optimum conditions for the measurement of the activity of a gamma transmitter isolated radioactive source with a spectrometer with germanium detector. (Author)

  9. Photo- and digital-detectors for quantitative digital densitometry for distribution analysis of ores by means of gamma-activation

    A method for photo processing of nuclear film detectors, which ensures higher reproducibility (about 2 %) of densitometry has been suggested. Application of the method allows for recovering fine mineralogical texture of a complex polymetallic ore of the Norilsk deposit with time series autoradiograms after computer processing. Some problems concerning interpretation of the results are discussed. It has been shown that application of digital imaging plates as a detector demonstrates high reproducibility suitable for precise quantitative autoradiography. The developed method of digital gamma-activation autoradiography via short-lived radionuclides may be successfully used for screening analysis of large area ore's thin sections. (author)

  10. Development of a new fast shower maximum detector based on microchannel plates photomultipliers (MCP-PMT) as an active element

    One possibility to make a fast and radiation resistant shower maximum (SM) detector is to use a secondary emitter as an active element. We present below test beam results, obtained with different types of photodetectors based on microchannel plates (MCPs) as the secondary emitter. We performed the measurements at the Fermilab Test Beam Facility with 120 GeV proton beam and 12 GeV and 32 GeV secondary beams. The goal of the measurement with 120 GeV protons was to determine time resolution for minimum ionizing particles (MIPs). The SM time resolution we obtained for this new type of detector is at the level of 20–30 ps. We estimate that a significant contribution to the detector response originates from secondary emission of the MCP. This work can be considered as the first step in building a new type of calorimeter based on this principle

  11. Development of a new fast shower maximum detector based on microchannel plates photomultipliers (MCP-PMT) as an active element

    Ronzhin, A.; Los, S.; Ramberg, E.; Spiropulu, M.; Apresyan, A.; Xie, S.; Kim, H.; Zatserklyaniy, A.

    2014-09-01

    One possibility to make a fast and radiation resistant shower maximum (SM) detector is to use a secondary emitter as an active element. We present below test beam results, obtained with different types of photodetectors based on microchannel plates (MCPs) as the secondary emitter. We performed the measurements at the Fermilab Test Beam Facility with 120 GeV proton beam and 12 GeV and 32 GeV secondary beams. The goal of the measurement with 120 GeV protons was to determine time resolution for minimum ionizing particles (MIPs). The SM time resolution we obtained for this new type of detector is at the level of 20-30 ps. We estimate that a significant contribution to the detector response originates from secondary emission of the MCP. This work can be considered as the first step in building a new type of calorimeter based on this principle.

  12. Active conductivity of plane two-barrier resonance tunnel structure as operating element of quantum cascade laser or detector

    Ju.O. Set; M.V. Tkach; Matijek, V. O.; O.M. Voitsekhivska

    2011-01-01

    Within the model of rectangular potentials and different effective masses of electrons in different elements of plane two-barrier resonance tunnel structure there is developed a theory of spectral parameters of quasi-stationary states and active conductivity for the case of mono-energetic electronic current interacting with electromagnetic field. It is shown that the two-barrier resonance tunnel structure can be utilized as a separate or active element of quantum cascade laser or detector. Fo...

  13. Liquid chromatography automatic system with optical activity laser detector and its applications

    A new liquid chromatographic system with polarimetric detection and a computer program allowing the output of chromatograms to a display on line and electronic data storing was designed, built and put to work. The chromatographic system includes the laser polarimetric detector, having a measuring interval of one second, the chromatographic columns, the continuous flux polarimeter tubes of 50 and 100 mm, the programs for data acquisition, processing and storing, and the technical know-how for its most efficiently application. Thirty minutes is all the time needed to obtain a chromatogram by this method which is reasonably shorter than the time required for any other known comparable technique, and offering, besides, lower operation cost. The combination of molecular exclusion liquid chromatography and laser polarimetric detection has turned into a carbohydrate separation and quantification system of basic importance for the evaluation of plants fluids of industrial interest (sugarcane, agave, vegetable extracts, etc.). It is described here the application of this system as an early or complementary indicator of leaf scald -disease that affects sugarcane plants-. Another application on algae extracts gave good results in the separation and identification of biologically active components. The introduction of this system in several research centers in Cuba and abroad has resulted in practical information for the industry. (Author)

  14. Speech enhancement via Mel-scale Wiener filtering with a frequency-wise voice activity detector

    This paper presents a speech enhancement system that enables a comfortable communication inside an automobile. A couple of novel concepts are proposed in an effort to improve two major building blocks in the existing speech enhancement systems: a voice activity detector (VAD) and a noise filtering algorithm. The proposed VAD classifies a given data frame as speech or noise at each frequency, enabling the frequency-wise updates of noise statistics and thereby improving the effectiveness of the noise filtering algorithms by providing more up-to-date noise statistics. The celebrated Wiener filter is adopted in this paper as the accompanying noise filtering algorithm, which results in significant noise suppression. Yet, the musical noise present in most Wiener filter-based systems prompts the idea of applying the Wiener filter in the Mel-scale in which the human auditory system responds to the external stimulation. It turns out that the Mel-scale Wiener filter creates some masking effects and thereby reduces musical noise significantly, leading to smooth transition between data frames

  15. A novel depleted monolithic active pixel sensor for future high energy physics detectors

    Fernandez-Perez, Sonia

    2016-01-01

    El Gran Colisionador de Hadrones (LHC) tiene previsto aumentar su luminosidad hasta siete veces su valor actual con el objetivo de ampliar su actual programa de física. Esta mejora se conoce con el nombre de High Luminosity LHC (HL-LHC) y está prevista para el año 2024-2026. El actual Inner Detector (ID) del detector de ALTAS será completamente reemplazado por uno nuevo para ajustarse a los rigurosos requisitos que impone el HL-LHC. Nuevos detectores de píxeles están siendo investigados para ...

  16. Measure of thermal neutron flux in the IPEN/MB-01 reactor using 197 Au wire activation detectors

    This dissertation has aimed at developing a neutron flux measurement technique by means of detectors activation analysis. The main task of this work was the implementation of this thermal neutron flux measurement technique, using gold wires as activation detectors in the IPEN/MB-01 reactor core. The neutron thermal flux spatial distribution was obtained by gold wire activation technique, with wire diameters of 0.125 mm and 0.250 mm in seven selected reactor experimental channels. The values of thermal flux were about 109 neutrons/cm2.s. This experiment has been the first one conducted with gold wires in the IPEN/MB-01 reactor, being this technique implemented for use by experiments in flux mapping of the core

  17. Cherenkov Detector for Measuring the 90-Sr Activity Using Silica Aerogel

    90Sr is a highly radio-toxic fission product, which may pollute the environment following an accident in a nuclear power plant. It is a pure b emitter and thus difficult to detect by standard methods. Recent progress in silica aerogel production as well as the new multi anode photomultiplier tubes offer possibilities for detection of 90Sr, based on Cherenkov radiation of β particles emitted by its daughter 90Y. An appropriate choice of the aerogel refractive index (produced in the range between 1.005 to 1.06) determines the threshold for Cherenkov radiation and thus separates between higher and lower energy β particles. Also multi anode PMT's permit the counting of the Cherenkov photon yield, offering additional discrimination. An apparatus is thus constructed for detection of the relatively higher energy β particles emitted by 90Y (Emax = 2.27 MeV). The efficiency of the detector and the photon yield as a function of the β spectrum end-point energy will be presented. The results obtained by the present test apparatus show a very low background rate, suitable for measurements of low activity environmental samples. The efficiencies obtained are however also low, which is due mainly to the low coverage of the aerogel area. This can be improved by either increasing the number of photomultipliers or by a photon concentrator such as a Winston cone. Also the problem of β-γ coincidences needs further attention. It is expected that with the above mentioned improvements and known solutions to problems, one could construct an apparatus capable of measuring low activities of 90Sr/90Y in environmental samples like air filters or sediments. (author)

  18. Tin Can Radiation Detector.

    Crull, John L.

    1986-01-01

    Provides instructions for making tin can radiation detectors from empty aluminum cans, aluminum foil, clear plastic, copper wire, silica gel, and fine, unwaxed dental floss put together with tape or glue. Also provides suggestions for activities using the detectors. (JN)

  19. Balloon Flight Background Measurement with Actively-Shielded Planar and Imaging CZT Detectors

    Bloser, P F; Jenkins, J A; Perrin, M; Murray, R; Grindlay, J E

    2001-01-01

    We present results from the flight of two prototype CZT detectors on a scientific balloon payload in September 2000. The first detector, referred to as ``CZT1,'' consisted of a 10 mm x 10 mm x 2 mm CZT crystal with a single gold planar electrode readout. This detector was shielded by a combination of a passive collimator surrounded by plastic scintillator and a thick BGO crystal in the rear. The second detector, ``CZT2,'' comprised two 10 mm x 10 mm x 5 mm CZT crystals, one made of eV Products high pressure Bridgman material and the other of IMARAD horizontal Bridgman material, each fashioned with a 4 x 4 array of gold pixels on a 2.5 mm pitch. The pixellated detectors were flip-chip-mounted side by side and read out by a 32-channel ASIC. This detector was also shielded by a passive/plastic collimator in the front, but used only additional passive/plastic shielding in the rear. Both experiments were flown from Ft. Sumner, NM on September 19, 2000 on a 24 hour balloon flight. CZT1 recorded a non-vetoed backgro...

  20. Segmented Ge detector rejection of internal beta activity produced by neutron irradiation

    Varnell, L. S.; Callas, J. L.; Mahoney, W. A.; Pehl, R. H.; Landis, D. A.

    1991-01-01

    Future Ge spectrometers flown in space to observe cosmic gamma-ray sources will incorporate segmented detectors to reduce the background from radioactivity produced by energetic particle reactions. To demonstrate the effectiveness of a segmented Ge detector in rejecting background events due to the beta decay of internal radioactivity, a laboratory experiment has been carried out in which radioactivity was produced in the detector by neutron irradiation. A Cf-252 source of neutrons was used to produce, by neutron capture on Ge-74 (36.5 percent of natural Ge) in the detector itself, Ge-75 (t sub 1/2 = 82.78 min), which decays by beta emission with a maximum electron kinetic energy of 1188 keV. By requiring that an ionizing event deposit energy in two or more of the five segments of the detector, each about 1-cm thick, the beta particles, which have a range of about 1-mm, are rejected, while most external gamma rays incident on the detector are counted. Analysis of this experiment indicates that over 85 percent of the beta events from the decay of Ge-75 are rejected, which is in good agreement with Monte Carlo calculations.

  1. Measurements of the neutron-spectra on the nuclear plants by means of the activation and fission detectors

    Here are presented the results of the neutron spectra determinations on the nuclear plants HPRR(USA), SILEN (FRANCE), and VIPER (GREAT BRITAIN) by means of a method developed in the Institute for Nuclear Sciences BORIS KIDRIC, Vinca based on the measurements of the induced activities in the activation detectors, created number of fissions in the fission detectors as well as on the measurements of the specific activity Na-24 in a phantom of BOMAB type. The measurements of the neutron spectra by means of the activation and fission detectors is particularly convenient on the nuclear plants operating on an impulse rate, where exist neutron fields of relatively high intensities. The forms of the neutron spectra on these plants measured by the method developed in the Institute BORIS KIDRIC for the needs of the accidental dosimetry are used to determine the mean values of the conversion factors fluens - absorbed dose of the neutrons for the energy interval 1 keV - 14 MeV. The results are compared with the values obtained by the other authors and in most cases the departures were within 10%. (author)

  2. Active conductivity of plane two-barrier resonance tunnel structure as operating element of quantum cascade laser or detector

    Ju.O. Set

    2011-06-01

    Full Text Available Within the model of rectangular potentials and different effective masses of electrons in different elements of plane two-barrier resonance tunnel structure there is developed a theory of spectral parameters of quasi-stationary states and active conductivity for the case of mono-energetic electronic current interacting with electromagnetic field. It is shown that the two-barrier resonance tunnel structure can be utilized as a separate or active element of quantum cascade laser or detector. For the experimentally studied In0.53Ga0.47As/In0.52Al0.48As nano-system it is established that the two-barrier resonance tunnel structure, in detector and laser regimes, optimally operates (with the biggest conductivity at the smallest exciting current at the quantum transitions between the lowest quasi-stationary states.

  3. Study on the measurement technique of threshold detectors' γ activated spectrum

    Using a method combining experimental measurement and Monte Carlo calculation, the measurement technique of high-threshold detectors is more systematically studied in special experimental conditions of small measurement inter-space and weak neutron flux. Influenced factors mostly include self-absorption of γ-ray in foils, self-shielding of neutrons, perturbation among detectors and scattered background neutrons and so on. the varied rules as function of a foil's thickness are attained. The study's results show that when the thickness of a foil is suited, the experimental systematical errors may fall down. The experimental-shielding method is used to proof-test the fraction of scattered back-ground neutrons, and for high-threshold detectors, the influence of background neutrons is very small. (authors)

  4. Simulation of active-edge pixelated CdTe radiation detectors

    Duarte, DD; Lipp, JD; Schneider, A.; Seller, P; Veale, MC; Wilson, MD; Baker, MA; Sellin, PJ

    2016-01-01

    The edge surfaces of single crystal CdTe play an important role in the electronic properties and performance of this material as an X-ray and γ-ray radiation detector. Edge effects have previously been reported to reduce the spectroscopic performance of the edge pixels in pixelated CdTe radiation detectors without guard bands. A novel Technology Computer Aided Design (TCAD) model based on experimental data has been developed to investigate these effects. The results presented in this paper sh...

  5. Measurement of volumic activities of radon in air in houses and in working rooms with solid state nuclear track detectors

    In this work, a new method of measuring volumic activity of radon has been developed. This method is based on using solid state nuclear track detectors LR-115 type II. It has been applied to measurement of volumic activities of radon in air in houses and in working rooms in different regions of Morocco. These measurements, carried out for the first time in the country, allowed to estimate the dose equivalents of radon received by the population of the studied regions. 59 refs., 38 figs., 38 tabs. (F.M.)

  6. Flight activity and habitat preference of bats in a karstic area, as revealed by bat detectors

    Zukal, Jan; Řehák, Z.

    2006-01-01

    Roč. 55, č. 3 (2006), s. 273-281. ISSN 0139-7893 Institutional research plan: CEZ:AV0Z60930519 Keywords : Moravian Karst * echolocation calls * bat community * detectoring Subject RIV: EG - Zoology Impact factor: 0.529, year: 2006 http://www.ivb.cz/folia/55/3/273-281.pdf

  7. A passive radon dosimeter based on the combination of a track etch detector and activated charcoal

    Deynse, A V; Poffijn, A

    1999-01-01

    The aim of this work is to test a combination of a Makrofol track detector with a new type of charcoal (Carboxen-564) to design a personal radon dosimeter. The intention is to use this dosimeter as a personal radon dosimeter to measure the monthly radon exposure in workplaces, especially when the occupancy is not exactly known. The proposed combination was exposed to low and high concentrations of radon in a large range of relative humidity (RH). For the optimal layer thickness, a charcoal bed of 2.2 mm, a specific track density of 5.1 tracks cm sup - sup 2 /kBq h m sup - sup 3 was obtained. For a monthly working exposure (170 h) at an average radon concentration of 100 Bq/m sup 3 , this means 87 tracks/cm sup 2 or 10 times the background of the Makrofol detector, with a statistical uncertainty of 15%.

  8. Simulation of active-edge pixelated CdTe radiation detectors

    Duarte, D. D.; Lipp, J. D.; Schneider, A.; Seller, P.; Veale, M. C.; Wilson, M. D.; Baker, M. A.; Sellin, P. J.

    2016-01-01

    The edge surfaces of single crystal CdTe play an important role in the electronic properties and performance of this material as an X-ray and γ-ray radiation detector. Edge effects have previously been reported to reduce the spectroscopic performance of the edge pixels in pixelated CdTe radiation detectors without guard bands. A novel Technology Computer Aided Design (TCAD) model based on experimental data has been developed to investigate these effects. The results presented in this paper show how localized low resistivity surfaces modify the internal electric field of CdTe creating potential wells. These result in a reduction of charge collection efficiency of the edge pixels, which compares well with experimental data.

  9. 3D Particle Track Reconstrution in a Single Layer Cadmium-Telluride Hybrid Active Pixel Detector

    Filipenko, Mykhaylo; Anton, Gisela; Michel, Thilo

    2014-01-01

    In the past 20 years the search for neutrinoless double beta decay has driven many developements in all kind of detector technology. A new branch in this field are highly-pixelated semiconductor detectors - such as the CdTe-Timepix detectors. It compromises a cadmium-telluride sensor of 14 mm x 14 mm x 1 mm size with an ASIC which has 256 x 256 pixel of 55 \\textmu m pixel pitch and can be used to obtain either spectroscopic or timing information in every pixel. In regular operation it can provide a 2D projection of particle trajectories; however, three dimensional trajectories are desirable for neutrinoless double beta decay and other applications. In this paper we present a method to obtain such trajectories. The method was developed and tested with simulations that assume some minor modifications to the Timepix ASIC. Also, we were able to test the method experimentally and in the best case achieved a position resolution of about 90 \\textmu m with electrons of 4.4 GeV.

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

    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

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

    Miucci, A.; 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.; Gonzalez-Sevilla, S.; Ferrere, D.; Iacobucci, G.; La Rosa, A.; 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.; HV-CMOS Collaboration

    2014-05-01

    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.

  12. Neutron Activation and Thermoluminescent Detector Responses to a Bare Pulse of the CEA Valduc SILENE Critical Assembly

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Celik, Cihangir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McMahan, Kimberly L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Yi-kang [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette (France); Gagnier, Emmanuel [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette (France); Authier, Nicolas [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille (France); Piot, Jerome [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille (France); Jacquet, Xavier [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille (France); Rousseau, Guillaume [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille (France); Reynolds, Kevin H. [Oak Ridge Y-12 Plant (Y-12), Oak Ridge, TN (United States)

    2015-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 11, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  13. Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

    E.H. Seabury; C.J. Wharton; A.J. Caffrey; J.B. McCabe; C. DeW. Van Siclen

    2013-10-01

    Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their use to areas where liquid nitrogen is readily available or produced on-site. Also, having a relatively large volume of liquid nitrogen close to the detector can impact some assessments, possibly leading to a false detection of explosives or other nitrogen-containing chemical. Use of a mechanically-cooled HPGe detector is therefore very attractive for PGNAA applications where nitrogen detection is critical or where liquid-nitrogen logistics are problematic. Mechanically-cooled HPGe detectors constructed from p-type germanium, such as Ortec’s trans-SPEC, have been commercially available for several years. In order to assess whether these detectors would be suitable for use in a fielded PGNAA system, Idaho National Laboratory (INL) has been performing a number of tests of the resistance of mechanically-cooled HPGe detectors to neutron damage. These detectors have been standard commercially-available p-type HPGe detectors as well as prototype n-type HPGe detectors. These tests compare the performance of these different detector types as a function of crystal temperature and incident neutron fluence on the crystal.

  14. Detection of trace elements in manufacturing silicon detectors by means of neutron activation analysis

    Trace elements impurities play an important role in manufacturing silicon radiation detectors which require silicon discs of highest purity, e.g. of doping concentrations of 1012 atoms/cm3. Metal contaminations in the range from ppb to ppt may drastically change the electric properties. The technological steps of the planar process were studied with a view to finding out the respective contamination pattern. Such patterns could be used as reference tools in analysing the single process steps in order to facilitate the analytical fault detection in the case of process variations. Knowledge of contamination patterns is also important for the process transfer to other laboratories and for a rapid optimization. (orig.)

  15. A new type active personal dosemeter with a solid state detector

    We have developed a new type personal dosemeter by using a B-10 doped silicon p-n junction detector with a polyethylene radiator and a polyethylene moderator. The purpose of this study was to develop a real time neutron dosemeter with a nearly flat response in the energy range from thermal to 15 MeV and low angular dependence to the incident neutron direction. The neutron response of the dosemeter was obtained with the Monte Carlo calculation and the monoenergetic neutron experiment in a free air field and also under a condition attached on a phantom

  16. Textile UV detector with 2,3,5-triphenyltetrazolium chloride as an active compound

    In this paper, results on the construction of a new flat textile-based UV light dosimeter are reported. As a textile support polyamide woven fabric was chosen, which was surface-modified with 2,3,5-triphenyltetrazolium chloride (TTC). At first, spectrophotometric and dynamic laser light scattering results on the steady-state UV irradiation of aqueous TTC solutions in the presence of oxygen are discussed. If irradiated, TTC converts to the corresponding formazan molecules of red colour. The size and size distribution of the particles is related to the absorbed radiation and pH of the solution. When TTC molecules reside on polyamide textile, UV irradiation causes a colour change from white to deep red. The tinge intensity depends on the absorbed energy per unit surface area. On this basis, the calibration parameters of the detectors, such as dose sensitivity, dose range, quasi-linear dose range, were calculated. Furthermore, the improvement of the dosimeters' resistance to atmospheric conditions was achieved and assessed through washing fastness tests. Finally, the detectors were proved to be adequate for measurements of the 2D distribution of absorbed UV energy. A simple method of UV dose distribution measurements was proposed. The textile-based systems show promise as dosimeters.

  17. Holmium-166m: multi-gamma standard to determine the activity of radionuclides in semiconductor detectors

    The efficiency and calibration curves as function of gamma-ray energy for a germanium detector are usually established by using many standard gamma ray sources of radionuclides decaying with few gamma rays or radionuclides having complex decay scheme, as 152Eu or 133Ba. But these radionuclides cannot be used alone, because they have a few gamma lines with high intensity and these lines have a irregular distribution in the energy spectrum. 166mHo is found to be a convenient single source for such calibration, because it decays by β- with subsequent emission of about 40 strong and well distributed gamma lines between 80 and 1500 keV. Moreover, its long half - life (1200 years) and X-rays characteristics between 40 and 50 keV makes it a good standard for calibration of germanium detectors. However, it is necessary to know with accuracy and precision the gamma ray intensities of their main lines, due to the fact that literature has showed discrepant values. Then, a methodology to determine the emission probability of its main lines is proposed by means of combined use of gamma spectrometry and coincidence 4πβ -γ techniques. The experimental results show consistence to the others authors, with lower or compatible uncertainties. (author)

  18. Silicon detectors

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  19. Scintillating glass, fiber-optic plate detectors for active target and tracking applications in high energy physics experiments

    The authors have studied the performance of scintillating glass fiber-optic plates using 10 GeV/c particles at the SLAC test beam. The plates were composed of: Terbium activated cladded-glass cores in a matrix of 15 μm spacing; and Cerium activated cladded-glass cores in a matrix of variable spacing 6-10 μm. The target plates were viewed with a three-stage, gatable image intensifier. Particle tracks and nuclear interactions were recorded on film for both materials. We observe 5 detected hits/mm for minimum ionizing particles for the Tb glass, and 1-2 hits/mm for the Ce glass. The test results indicate that scintillating glass fiber-optic plates can be used as high spatial resolution tracking detectors for both fixed target and colliding beam experiments

  20. Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

    Chen, Jiunn-Wei; Chi, Hsin-Chang; Lin, Shin-Ted; Liu, C.-P.; Singh, Lakhwinder; Wong, Henry T.; Wu, Chih-Liang; Wu, Chih-Pan

    2016-05-01

    The transition magnetic moment of a sterile neutrino can give rise to its conversion to an active neutrino through radiative decay or nonstandard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic x-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with low-threshold low-background germanium detectors, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from astrophysical observations.

  1. The C shell, an active detector of UH nuclei. [in cosmic radiation

    Waddington, C. J.; Clinton, Robert R.

    1990-01-01

    This paper gives a brief description of the current status of the present program to develop a modular array of large electronic particle detectors. These modules were designed to study the UH nuclei in the cosmic radiation with eventual deployment on the Space Station or at a lunar base. This array would determine the abundances of elements from iron to the actinides and directly measure the energies of the lower energy nuclei. If the array was deployed on the Space Station, it would use the geomagnetic threshold to place limits on the higher energy nuclei, thus studying the energy spectrum up to about 10 GeV/n. Deployed at a lunar base, it would detect nuclei with energies down to the instrumental limit. Smaller versions could be flown on balloons to test and refine the modules.

  2. High voltage monolithic active pixel sensors for the PANDA luminosity detector

    The PANDA-Experiment will be part of the new FAIR accelerator center at Darmstadt, Germany. It is a fixed target experiment using a antiproton beam with very high resolution for precision measurements. For a variety of measurements like energy-scans the precise determination of the luminosity is needed. The luminosity detector will determine the luminosity by measuring the angular distribution of elastically scattered antiprotons very close to the beam axis (3-8 mrad). To reconstruct antiproton tracks four layers of thinned silicon sensors with smart pixel readout on chip (HV-MAPS) will be used. Those sensors are currently under development by the Mu3e-collaboration. In the talk the concept of the luminosity measurement is shortly introduced before a summary of the status of HV-MAP prototypes and recent test beam results are presented.

  3. The engineering development of an actively controlled precise muon chamber for the SDC detector

    As the detector configuration for the Solenoidal Detector Collaboration (SDC) evolved, a number of concepts for MUON chambers were proposed and investigated. The Boston Group (Brandeis, Harvard and Tufts Universities, with Draper Laboratory) has developed a concept incorporating elliptical section drift tubes with field shaping and intermediate wire supports. This approach combines good single and multi-track resolution with a small channel count and modularity at the tube level. Other concepts have been developed which arise from differing interpretations of the fundamental physics and economic requirements. These include: Octagonal Drift Tubes, Unsupported Wires, No Field Shaping, U. Wisconsin; Round Tubes, Unsupported Wires, w or w/o Field Shaping, U. Washington; JFT Chambers (Multi-Wire, Intermediate Support, Field Shaping), KEK, Japan. This paper outlines the mechanical implementation of the Boston MUON chamber concept and discusses the rationale for several key design decisions imposed by the stringent mechanical tolerances. A prototype MUON chamber designed to verify design feasibility, performance, and cost is also described. A special section is devoted to the design and development of an optical alignment system within the chamber, which provides error signals driving the intermediate supports to true position. The Boston subgroup MUON chamber design is called the wine rack concept by virtue of its numerous (non-structural) drift tubes laid into a supporting chamber, which provides structural and handling capability. A number of individual θ,φ, and Stereo chambers is normally grouped into a supermodule, which in turn is assembled into a multi-layer supertower. Supertowers are the basic elements of the SDC MUON System, each comprising three supermodule layers in the barrel region and five in the forward regions

  4. Design and Preliminary Monte Carlo Calculations of an Active Compton Suppressed LaBr3(Ce) Detector System for TRU Assay in Remote-Handled Wastes

    Recent studies indicate LaBr3(Ce) scintillation detectors have desirable attributes, such as room temperature operability, which may make them viable alternatives as primary detectors (PD) in a Compton suppression spectrometer (CSS) used for remote-handled transuranic (RH-TRU) waste assay. A CSS with a LaBr3(Ce) PD has been designed and its expected performance evaluated using Monte Carlo analysis. The unique design of this unit minimizes the amount of ''dead'' material between the PD and the secondary guard detector. The analysis results indicate that this detector will have a relatively high Compton-suppression capability, with greater suppression ability for large angle-scattered photons in the PD. J. K. Hartwell1, M. E. McIlwain1, R. P. Gardner2, J. Kulisek3 (1) Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2114 USA (2) North Carolina State University, Dept of Nuclear Eng., PO Box 7909, Raleigh, NC 27695 USA (3) Ohio State University, Columbus, Ohio 43210 The US Department of Energy's transuranic (TRU) waste inventory includes about 4,500 m3 of remote-handled TRU (RH-TRU) wastes. The RH-TRU waste stream is composed of a variety of containerized waste forms having a contact surface dose rate that exceeds 2 mSv/hr (200 mrem/hr) containing waste materials with a total TRU concentration greater than 3700 Bq/g (100 nCi/g). As part of a research project to investigate the use of active Compton-suppressed room-temperature gamma-ray detectors for direct non-destructive quantification of the TRU content of these RH-TRU wastes, we have designed and purchased a unique detector system using a LaBr3(Ce) primary detector and a NaI(Tl) suppression mantle. The expected detector performance has been modeled using MCNP-X [1] and CEARCPG [2], and incorporates certain design features modeled as important to active Compton suppression systems in previously-published work [3]. The unique detector system is sketched in Fig. 1. The ∼25 mm diameter by 75 mm long LaBr3

  5. Characteristics and application of spherical-type activation detectors in neutron spectrum measurements at a boron neutron capture therapy (BNCT) facility

    Lin, Heng-Xiao; Chen, Wei-Lin; Liu, Yuan-Hao; Sheu, Rong-Jiun

    2016-03-01

    A set of spherical-type activation detectors was developed aiming to provide better determination of the neutron spectrum at the Tsing Hua Open-pool Reactor (THOR) BNCT facility. An activation foil embedded in a specially designed spherical holder exhibits three advantages: (1) minimizing the effect of neutron angular dependence, (2) creating response functions with broadened coverage of neutron energies by introducing additional moderators or absorbers to the central activation foil, and (3) reducing irradiation time because of improved detection efficiencies to epithermal neutron beam. This paper presents the design concept and the calculated response functions of new detectors. Theoretical and experimental demonstrations of the performance of the detectors are provided through comparisons of the unfolded neutron spectra determined using this method and conventional multiple-foil activation techniques.

  6. Detection systems for mass spectrometry imaging: a perspective on novel developments with a focus on active pixel detectors

    Jungmann, JH; Heeren, R.M.A.

    2013-01-01

    Instrumental developments for imaging and individual particle detection for biomolecular mass spectrometry (imaging) and fundamental atomic and molecular physics studies are reviewed. Ion-counting detectors, array detection systems and highmass detectors for mass spectrometry (imaging) are treated.

  7. The AFIS experiment: Detecting low energetic antiprotons in a low earth orbit, using an active target detector

    Poeschl, Thomas; Gaisbauer, Dominic; Greenwald, Daniel; Hahn, Alexander; Hauptmann, Philipp; Konorov, Igor; Meng, Lingxin; Paul, Stephan [Physics Department E18, Technische Universitaet Muenchen (Germany); Losekamm, Martin [Physics Department E18, Technische Universitaet Muenchen (Germany); Institute of Astronautics, Technische Universitaet Muenchen (Germany); Renker, Dieter [Physics Department E17, Technische Universitaet Muenchen (Germany)

    2014-07-01

    Since the first observation of geomagnetically trapped antiprotons by the PAMELA experiment and the new results on the positron excess by the AMS-02 experiment, the creation and transport of antimatter in the Earth's upper atmosphere attracts more and more attention both at theoretical and experimental side. For this reason the AFIS experiment was initiated to measure the flux of low energetic antiprotons in the South Atlantic Anomaly (SAA). We developed an active target detector made from scintillating fibers connected to silicon photomultipliers which allows to detect antiprotons in the energy interval of about 30 MeV-100 MeV. The stopping curve of incoming antiprotons (Bragg peak) and the signal of outgoing pions created from the annihilation, are used for particle identification as well as triggering. We plan to implement this detector on a 3 unit cubesat satellite in the framework the 'Move2Warp' mission, which is carried out as a student project by the Technische Universitaet Muenchen.

  8. The development of a thermal neutron activation (TNA) system as a confirmatory non-metallic land mine detector

    In order to detect and locate buried landmines for peacekeeping, the Canadian Department of National Defence (DND), under the Improved Landmine Detection Project, is developing a vehicle-mounted, two-phase mine detection system. The first phase constitutes a suite of detectors used to indicate the possibility of a mine at a particular location (to ±30 cm in accuracy). In the second phase a Thermal Neutron Activation (TNA) system is used to confirm the presence of explosives via detection of the 10.83 MeV gamma-ray associated with nitrogen decay. The TNA system developed for this uses a 100 μg 252Cf neutron source surrounded by four 3'x3' NaI(Tl) detectors. Combining the use of state-of-the art radiation transport codes for design, judicious choice of specialized shielding materials and development of high-rate, fast-pulse processing electronics, has led to a system which can; (i) confirm the presence of all surface- or lightly-buried anti-tank mines in a few seconds to a minute (depending on mass of explosive), (ii) confirm the presence of anti-tank mines down to 20 cm depth in less than 5 minutes, (iii) confirm the presence of large (> 100 g nitrogen) anti-personnel mines in less than five minutes, (iv) operate in adverse climatic conditions. These results have been verified in field trials and the system is due to be fielded in 1999. (author)

  9. Voice Activity Detector of Wake-Up-Word Speech Recognition System Design on FPGA

    Veton Z. Këpuska; Mohamed M. Eljhani; Brian H. Hight

    2014-01-01

    A typical speech recognition system is push-to-talk operated that requires activation. However for those who use hands-busy applications, movement may by restricted or impossible. One alternative is to use Speech-Only Interface. The proposed method that is called Wake-Up-Word Speech Recognition (WUW-SR) that utilizes speech only interface. A WUW-SR system would allow the user to activate systems (Cell phone, Computer, etc.) with only speech commands instead of manual activation. T...

  10. Ionization detector

    A novel ionization detector for use in X-ray tomography is described in detail. To achieve the ultimate resolution, the use of small detectors is necessary and, for ionization detectors, this implies using xenon gas at high pressure. Conventional small detectors can suffer from ''bowing'' but the present design overcomes their problems. (U.K.)

  11. Regular radon activity concentration and effective dose measurements inside the great pyramid with passive nuclear track detectors.

    Hafez, A F; Bishara, A A; Kotb, M A; Hussein, A S

    2003-08-01

    Radon activity concentrations and equilibrium factors inside the great pyramid of "Cheops" were measured with passive nuclear track detectors. The variation of these concentrations in location was investigated. Seasonal variation of radon activity concentrations with winter maximum and summer minimum were observed inside the pyramid. The 1-y average radon activity concentration ranged from a minimum of 20 to a maximum of 170 Bq m(-3). Results show that the yearly average equilibrium factor between radon and its progeny was assessed as 0.16 and 0.36 inside the pyramid and near entrance, respectively. Moreover, the estimated annual effective dose was 0.05 mSv to tour guides and varied from 0.19 to 0.36 mSv for the pyramid guards; for visitors the average effective dose was 0.15 microSv per visit. These are lower than the 3-10 mSv y(-1) dose limit recommend by ICRP 65. PMID:12938968

  12. Development of a wearable motion detector for telemonitoring and real-time identification of physical activity.

    Yang, Che-Chang; Hsu, Yeh-Liang

    2009-01-01

    Characteristics of physical activity are indicative of one's mobility level, latent chronic diseases, and aging process. Current research has been oriented to provide quantitative assessment of physical activity with ambulatory monitoring approaches. This study presents the design of a portable microprocessor-based accelerometry measuring device to implement real-time physical activity identification. An algorithm was developed to process real-time tri-axial acceleration signals produced by human movement to identify targeted still postures, postural transitions, and dynamic movements. Fall detection was also featured in this algorithm to meet the increasing needs of elderly care in free-living environments. High identification accuracy was obtained in performance evaluation. This device is technically viable for telemonitoring and real-time identification of physical activity, while providing sufficient information to evaluate a person's activity of daily living and her/his status of physical mobility. Limitations regarding real-time processing and implementation of the system for telemonitoring in the home environment were also observed. PMID:19199849

  13. Feasibility study of the water Cherenkov detector as a D-T fusion power monitor in the system using neutron activation of flowing water. First experimental phase

    The technique of monitoring D-T neutrons using water flow is based on the reaction of the 16O(n, p)16N. In order to significantly improve the D-T neutron monitoring system in the ITER reactor in comparison with the system that uses a γ-ray scintillation detector, a new approach was proposed. The basic idea of this approach is to utilize the Cherenkov light, produced by energetic β-particles from 16N in water near the first wall of the fusion reactor, and then deliver the light by the optical fiber to the remote light detector. The proof of the principle experiment is divided into two phases. The main idea of the first experimental phase is to examine Cherenkov light measurements using a remotely located water and light detector. During the second phase the water radiator will be placed next to the neutron source, then the Cherenkov light will be transferred by an optical fiber to the remotely located light detector. For the purpose of the first experimental phase, a water Cherenkov detector was installed in the shielded measurement room. A closed water loop, with circulating water, was used to transport 16N from the D-T source to the Cherenkov detector. The experiment was carried out at FNS/JAERI, with the accelerator set to a direct current mode, the source neutron yield around 2 x 1011 n/s, and the water flowage approximately 2 m/s. The registered Cherenkov signal was identified as the light produced by β-particles from 16N using the time decay and the energy spectra data. According to the present study, the water Cherenkov detector is very effective for measurements of the 16N activity, due to high counting efficiency, absence of the scintillation detector and simplicity of the method. (author)

  14. The self-shielding factors in activation detectors used in the IPEN/MB-01 reactor

    This work aims to obtain self-shielding factors (G) to several activation foils, such as gold, cobalt, scandium, magnesium, uranium, thorium and indium foils used at measurements of the neutron spectrum energy in the IPEN/MB-01 reactor core. The knowledge of the self-shielding factors allows obtaining of precise nuclear reaction rates without the effects of neutron flux depression inside of activation foils. This study is carried out in two parts. First are determined the self-shielding factors for bare foils (without cadmium covered) and after the self-shielding factors to foils with cadmium covered. (author)

  15. Application of epithermal neutron activation in multielement analysis of silicate rocks employing both coaxial Ge(Li) and low energy photon detector systems

    Baedecker, P.A.; Rowe, J.J.; Steinnes, E.

    1977-01-01

    The instrumental activation analysis of silicate rocks using epithermal neutrons has been studied using both high resolution coaxial Ge(Li) detectors and low energy photon detectors, and applied to the determination of 23 elements in eight new U.S.G.S. standard rocks. The analytical use X-ray peaks associated with electron capture or internal conversion processes has been evaluated. Of 28 elements which can be considered to be determinable by instrumental means, the epithermal activation approach is capable of giving improved sensitivity and precision in 16 cases, over the normal INAA procedure. In eleven cases the use of the low energy photon detector is thought to show advantages over convertional coaxial Ge(Li) spectroscopy. ?? 1977 Akade??miai Kiado??.

  16. The HERMES Recoil Detector

    Kaiser, R.

    2006-07-01

    The HERMES Collaboration is installing a new Recoil Detector to upgrade the spectrometer for measurements of hard exclusive electron/positron scattering reactions, in particular deeply virtual Compton scattering. These measurements will provide access to generalised parton distributions and hence to the localisation of quarks inside hadrons and to their orbital angular momentum. The HERMES Recoil Detector consists of three active components: a silicon detector surrounding the target cell inside the beam vacuum, a scintillating fibre tracker and a photon detector consisting of three layers of tungsten/scintillator. All three detectors are located inside a solenoidal magnetic field of 1 Tesla. The Recoil Detector was extensively tested with cosmic muons over the summer of 2005 and is being installed in the winter of 2005/6 for data taking until summer 2007.

  17. The HERMES Recoil Detector

    The HERMES Collaboration is installing a new Recoil Detector to upgrade the spectrometer for measurements of hard exclusive electron/positron scattering reactions, in particular deeply virtual Compton scattering. These measurements will provide access to generalised parton distributions and hence to the localisation of quarks inside hadrons and to their orbital angular momentum. The HERMES Recoil Detector consists of three active components: a silicon detector surrounding the target cell inside the beam vacuum, a scintillating fibre tracker and a photon detector consisting of three layers of tungsten/scintillator. All three detectors are located inside a solenoidal magnetic field of 1 Tesla. The Recoil Detector was extensively tested with cosmic muons over the summer of 2005 and is being installed in the winter of 2005/6 for data taking until summer 2007

  18. A high frequency transient detector suitable for monitoring marine mammal activity

    Laterveer, R.; Beerens, S.P.; IJsselmuide, S.P. van; Snyder, M.; Newcomb, J.

    2004-01-01

    As part of a program to study the effect of man-made noise on marine mammals an EARS Acoustic Recording System) buoy was deployed in the Ligurian sea. The EARS buoy was deployed at a position with a high probability of marine mammal activity at a depth of around 950 m. It was operating for almost 19

  19. Determination of radioactive trace elements in ultra low background detectors by means of neutron activation analysis

    In this paper new analytical methods for the determination of naturally occurring radionuclides are being presented. They combine neutron activation, radiochemical separation and coincidence counting techniques. For complex matrices such as organic liquids and silicon we have obtained detection limits lower than 10-14 g/g for Th, U, La and lower than 10-12 g/g for Cd, In, K, Lu, and Rb with radiochemical separation methods geared to the nuclides investigated. The β-γ coincidence counting techniques used for the determination of U, Th and Lu in the ultra trace region are discussed in detail, with recorded spectra and applied selection criteria for the evaluation of decay events. Impacts of the results on low level experiments in the field of astro and particle physics are being discussed as well as the advantage of neutron activation analysis which is sensitive to most naturally occurring radionuclides. (author)

  20. Efficiency calibration of a HPGe detector for [{sup 18}F] FDG activity measurements

    Fragoso, Maria da Conceicao de Farias; Lacerda, Isabelle Viviane Batista de; Albuquerque, Antonio Morais de Sa, E-mail: mariacc05@yahoo.com.br, E-mail: isabelle.lacerda@ufpe.br, E-mail: moraisalbuquerque@hotmaiI.com [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Oliveira, Mercia Liane de; Hazin, Clovis Abrahao; Lima, Fernando Roberto de Andrade, E-mail: mercial@cnen.gov.br, E-mail: chazin@cnen.gov.br, E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2013-11-01

    The radionuclide {sup 18}F, in the form of flurodeoxyglucose (FDG), is the most used radiopharmaceutical for Positron Emission Tomography (PET). Due to [{sup 18}F]FDG increasing demand, it is important to ensure high quality activity measurements in the nuclear medicine practice. Therefore, standardized reference sources are necessary to calibrate of {sup 18}F measuring systems. Usually, the activity measurements are performed in re-entrant ionization chambers, also known as radionuclide calibrators. Among the existing alternatives for the standardization of radioactive sources, the method known as gamma spectrometry is widely used for short-lived radionuclides, since it is essential to minimize source preparation time. The purpose of this work was to perform the standardization of the [{sup 18}F]FDG solution by gamma spectrometry. In addition, the reference sources calibrated by this method can be used to calibrate and test the radionuclide calibrators from the Divisao de Producao de Radiofarmacos (DIPRA) of the Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE). Standard sources of {sup 152}Eu, {sup 137}Cs and {sup 68}Ge were used for the efficiency calibration of the spectrometer system. As a result, the efficiency curve as a function of energy was determined in wide energy range from 122 to 1408 keV. Reference sources obtained by this method can be used in [{sup 18}F]FDG activity measurements comparison programs for PET services localized in the Brazilian Northeast region. (author)

  1. Efficiency calibration of a HPGe detector for [18F] FDG activity measurements

    The radionuclide 18F, in the form of flurodeoxyglucose (FDG), is the most used radiopharmaceutical for Positron Emission Tomography (PET). Due to [18F]FDG increasing demand, it is important to ensure high quality activity measurements in the nuclear medicine practice. Therefore, standardized reference sources are necessary to calibrate of 18F measuring systems. Usually, the activity measurements are performed in re-entrant ionization chambers, also known as radionuclide calibrators. Among the existing alternatives for the standardization of radioactive sources, the method known as gamma spectrometry is widely used for short-lived radionuclides, since it is essential to minimize source preparation time. The purpose of this work was to perform the standardization of the [18F]FDG solution by gamma spectrometry. In addition, the reference sources calibrated by this method can be used to calibrate and test the radionuclide calibrators from the Divisao de Producao de Radiofarmacos (DIPRA) of the Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE). Standard sources of 152Eu, 137Cs and 68Ge were used for the efficiency calibration of the spectrometer system. As a result, the efficiency curve as a function of energy was determined in wide energy range from 122 to 1408 keV. Reference sources obtained by this method can be used in [18F]FDG activity measurements comparison programs for PET services localized in the Brazilian Northeast region. (author)

  2. Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

    Chen, Jiunn-Wei; Lin, Shin-Ted; Liu, C -P; Singh, Lakhwinder; Wong, Henry T; Wu, Chih-Liang; Wu, Chih-Pan

    2016-01-01

    The transition magnetic moment of a sterile-to-active neutrino conversion gives rise to not only radiative decay of a sterile neutrino, but also its non-standard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic X-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with germanium detectors that have fine energy resolution in keV and sub-keV regimes, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from ast...

  3. Simulation of a multi-detector gamma camera for validation protocols of quantification the activity from SPECT images

    The main sources that decreasing accuracy in the estimation of internal absorbed dose has been identified in the methods for the quantification of cumulated activity from scintigraphic imaging, likes the corrections required by the physical and instrumental phenomena related to the formation of those images. The results of the simulation of a dual detector gamma camera E.cam SIEMENS using the Monte Carlo code SIMIND to obtain tomographic SPECT projections are presented here. SIMIND will allow dealing with the contribution of physical interactions and instrumental effects during simulations. Energy resolution, spatial resolution and sensitivity planar were determined with real and simulated systems. The relative differences did not exceed 10%. Energy spectra simulated under different conditions (source in air and water) with the inclusion of interactions in the collimator and phantom were compared. The tomographic sensitivity of a volumetric phantom containing radioactive solutions of 99mTc and 131I were determined from real and simulated SPECT images. Two processing protocols were considered: with scatter correction (99mTc dual energy window method and 131I were calculated after corrections. The results, expressed in terms of the differences relative to the well-know activity value in the phantom inserts improves when attenuation and scattering corrections are applied, obtaining good agreement between the results for real and simulated systems. (Author)

  4. GEM-MSTPC: An active-target type detector in low-pressure He/CO2 mixed gas

    We developed an active-target type gas counter operating with low pressure He/CO2(10%) detector gas for application in studying low-energy nuclear reactions using radioactive nuclear beams (RNBs). A 400-μm-thick gas electron multiplier (THGEM) was used as the proportional counter for high injection rate capability. We examined the gas gain stability and the influence of ion feedback on particle tracks at high beam injection rates of up to 105 particles per second (pps) using a low-energy 12C beam. By means of modifications to the THGEM, the shift in the relative pulse height of the output signal normalized to that measured at the 12C injection rate of several hundred pps improved to within 2% at the rate of 105 pps. The position distortion induced by ion feedback was suppressed to within 1.5 mm because of the relatively high drift field value of 1 kV/cm⋅atm and the use of the double GEM configuration. The THGEM was found to be applicable for our active target at high injection rates of up to 105 pps.

  5. Influence of a priori information and choice of activation detectors in integral experiments on the accuracy of neutron spectrum unfolding in fusion reactor blanket models

    The document contains the following two papers translated from Russian: Choice of activation detectors for integral experiments in the fusion reactor blanket models; Influence of a priori information on the accuracy of ''thermonuclear'' neutron spectrum unfolding. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  6. A Wireless Object Location Detector Enabling People with Developmental Disabilities to Control Environmental Stimulation through Simple Occupational Activities with Nintendo Wii Balance Boards

    Shih, Ching-Hsiang; Chang, Man-Ling

    2012-01-01

    The latest researches have adopted software technology, turning the Nintendo Wii Balance Board into a high performance standing location detector with a newly developed standing location detection program (SLDP). This study extended SLDP functionality to assess whether two people with developmental disabilities would be able to actively perform…

  7. A Semi-Continuous State-Transition Probability HMM-Based Voice Activity Detector

    Othman H

    2007-01-01

    Full Text Available We introduce an efficient hidden Markov model-based voice activity detection (VAD algorithm with time-variant state-transition probabilities in the underlying Markov chain. The transition probabilities vary in an exponential charge/discharge scheme and are softly merged with state conditional likelihood into a final VAD decision. Working in the domain of ITU-T G.729 parameters, with no additional cost for feature extraction, the proposed algorithm significantly outperforms G.729 Annex B VAD while providing a balanced tradeoff between clipping and false detection errors. The performance compares very favorably with the adaptive multirate VAD, option 2 (AMR2.

  8. A Semi-Continuous State-Transition Probability HMM-Based Voice Activity Detector

    H. Othman

    2007-02-01

    Full Text Available We introduce an efficient hidden Markov model-based voice activity detection (VAD algorithm with time-variant state-transition probabilities in the underlying Markov chain. The transition probabilities vary in an exponential charge/discharge scheme and are softly merged with state conditional likelihood into a final VAD decision. Working in the domain of ITU-T G.729 parameters, with no additional cost for feature extraction, the proposed algorithm significantly outperforms G.729 Annex B VAD while providing a balanced tradeoff between clipping and false detection errors. The performance compares very favorably with the adaptive multirate VAD, option 2 (AMR2.

  9. Search of high energy neutrino flares from active galactic nuclei with the IceCube detector

    Cruz Silva, Angel Humberto; Bernardini, Elisa [DESY, Platanenallee 6, D 15738 Zeuthen (Germany); Gora, Dariusz [DESY, Platanenallee 6, D 15738 Zeuthen (Germany); Institute of Nuclear Physics PAN, ul. Radzikowskiego 152,31-342 Cracow, Krakow (Poland); Collaboration: IceCube-Collaboration

    2013-07-01

    Active Galactic Nuclei (AGN) are among the best candidates for sources of high energy cosmic rays. One of their properties is the extreme variability in their electromagnetic emission at different wavelengths with flare durations ranging from minutes, in some cases, to several weeks. This photon flares may be correlated with neutrinos emitted from the same source if protons are also accelerated in the AGN relativistic jet. Here we present a new statistical test method to look for neutrino flares from selected AGNs. The method takes into account a list of possible neutrino sources from different categories (FSRQs and BL-Lacs) in a so called stacking approach. The performance and results of the method using IceCube data in its 79 string configuration are presented.

  10. CERN-RD39 collaboration activities aimed at cryogenic silicon detector application in high-luminosity Large Hadron Collider

    Li, Zheng; Eremin, Vladimir; Verbitskaya, Elena; Dehning, Bernd; Sapinski, Mariusz; Bartosik, Marcin R.; Alexopoulos, Andreas; Kurfürst, Christoph; Härkönen, Jaakko

    2016-07-01

    Beam Loss Monitors (BLM) made of silicon are new devices for monitoring of radiation environment in the vicinity of superconductive magnets of the Large Hadron Collider. The challenge of BLMs is extreme radiation hardness, up to 1016 protons/cm2 while placed in superfluid helium (temperature of 1.9 K). CERN BE-BI-BL group, together with CERN-RD39 collaboration, has developed prototypes of BLMs and investigated their device physics. An overview of this development-results of the in situ radiation tests of planar silicon detectors at 1.9 K, performed in 2012 and 2014-is presented. Our main finding is that silicon detectors survive under irradiation to 1×1016 p/cm2 at 1.9 K. In order to improve charge collection, current injection into the detector sensitive region (Current Injection Detector (CID)) was tested. The results indicate that the detector signal increases while operated in CID mode.

  11. Measuring the activity of neutron-activation detectors using gamma-spectroscopy technique in the presence of positron decay

    The present paper is of methodical character and is aimed at drawing experimentators' attention to the systematic error sources occurring on positron-decay nuclide activity measuring with gamma spectrometric method. The paper deals with summing in the detection unit the signals from the measured photons with energy Eph to those from annihilation radiation photons. Summation results in decrease of the area under the total energy absorption peak for measured photons and, as the consequence, in decrease of the sample external radiation measured value

  12. Detrmination of the Si-Pin Detector Active Zone Thickness Using Analytic Line Intensity Wavelength Dependence of the Single-Component Standards

    А.А. Mamaluy

    2010-01-01

    Full Text Available The simple procedure of the detector active zone thickness determination is proposed, in which the fluxes of fluorescent radiation analytical lines from single-component samples excited by monochromatic radiation of a secondary radiator are used as the known fluxes. The superposition of experimental and calculated curves of the analytical line intensity versus the wavelength allows determination of the active zone thickness d = 170 μm with an accuracy of ± 10 μm.

  13. ABC 27-2 General bat activity measured with an ultrasound detector in a fragmented tropical landscape in Los Tuxtlas, Mexico

    Estrada, A.; Jímemez, C.; A. Rivera; Fuentes, E.

    2004-01-01

    Bat tolerance to neotropical forest fragmentation may be related to ability by bats to use available habitats in the modified environmental matrix. This paper presents data on general bat activity (for three hours starting at dusk) measured with an ultrasound detector in a fragmented landscape in the region of Los Tuxtlas, Mexico. Bat activity was measured in continuous forests, forests fragments, forest-pasture edges, forest corridors, linear strips of vegetation, citrus groves, pastures and...

  14. Improvement of in vivo neutron activation analysis of Mn using a 4π NaI(Tl) detector array

    Manganese contents in hand phantoms were analyzed by in vivo neutron activation analysis using a 4π NaI(Tl) detector array. Solution-type phantoms with varying amount of Mn and fixed amounts of physiological normal elements (Na, Cl, Ca) were prepared in a cylindrical shape to simulate fisted hands and were irradiated with the 7Li(p,n) neutron beam. The proton energy and polyethlyene cavity were set at optimized conditions established before. The γ-ray spectra were accumulated under the anticoincidence mode. The calibration was done both for the 847 keV full-energy peak area and for the total area of 56Mn, which is defined as the total number of counts anywhere in the γ-ray spectrum from 56Mn. From the analysis of the 847 keV peak, the Mn detection limit has been improved by a factor of 1.6 compared to the previous feasibility test thanks to a significant gain in the γ-ray detection efficiency. Further improvement by a factor of 1.2 was identified when the total area of 56Mn was used for the calibration. The final sensitivity and detection limit for a 20 mSv hand dose reached 12,050 counts/mg Mn, and 86 μg, respectively. The overall improvement achieved in this study will be a considerable contribution toward realization of the clinical application. (author)

  15. Scintillating glass, fiber-optic plate detectors for active target and tracking applications in high energy physics experiments

    We have been developing a scintillating glass fiber-optic imaging system for active target and tracking applications in high energy physics experiments. Extensive measurements have been performed on several scintillating-glass compositions, one of which is a silicate-glass containing 0.6 mole % of Ce2O3 known commercially as NRL glass. For this material, fabricated into coherent fiber-optic plates of 10 μm and 25 μm diameter cladded-glass fibers, have observed clear particle tracks and interactions and a yield of about 2 photoelectrons per millimeter of path length for minimum ionizing particles. Additionally, for the bulk NRL glass formed in disks of 1'' diameter and 4 mm thickness, we have observed a about 80% retention of optical transmission through 4 mm of material at 395 mm (the peak of the fluorescence spectrum) for a radiation dose in excess of 107 rads acquired over several days. Results of these tests and others suggest that Ce2O3 based scintillating glasses constitute very promising materials for the fabrication of high resolution tracking detectors for fixed target and colliding beam applications

  16. Study of the timing performance of micro-channel plate photomultiplier for use as an active layer in a shower maximum detector

    Ronzhin, A.; Los, S.; Ramberg, E.; Apresyan, A.; Xie, S.; Spiropulu, M.; Kim, H.

    2015-09-01

    We continue the study of micro-channel plate photomultiplier (MCP-PMT) as the active element of a shower maximum (SM) detector. We present test beam results obtained with Photek 240 and Photonis XP85011 MCP-PMTs devices. For proton beams, we obtained a time resolution of 9.6 ps, representing a significant improvement over past results using the same time of flight system. For electron beams, the time resolution obtained for this new type of SM detector is measured to be at the level of 13 ps when we use Photek 240 as the active element of the SM. Using the Photonis XP85011 MCP-PMT as the active element of the SM, we performed time resolution measurements with pixel readout, and achieved a TR better than 30 ps, The pixel readout was observed to improve upon the TR compared to the case where the individual channels were summed.

  17. Study of the timing performance of micro-channel plate photomultiplier for use as an active layer in a shower maximum detector

    Ronzhin, A., E-mail: ronzhin@fnal.gov [Fermilab, Batavia, Il 60510 (United States); Los, S.; Ramberg, E. [Fermilab, Batavia, Il 60510 (United States); Apresyan, A.; Xie, S.; Spiropulu, M. [California Institute of Technology, Pasadena, CA 91126 (United States); Kim, H. [University of Chicago, Chicago, Il 60637 (United States)

    2015-09-21

    We continue the study of micro-channel plate photomultiplier (MCP-PMT) as the active element of a shower maximum (SM) detector. We present test beam results obtained with Photek 240 and Photonis XP85011 MCP-PMTs devices. For proton beams, we obtained a time resolution of 9.6 ps, representing a significant improvement over past results using the same time of flight system. For electron beams, the time resolution obtained for this new type of SM detector is measured to be at the level of 13 ps when we use Photek 240 as the active element of the SM. Using the Photonis XP85011 MCP-PMT as the active element of the SM, we performed time resolution measurements with pixel readout, and achieved a TR better than 30 ps, The pixel readout was observed to improve upon the TR compared to the case where the individual channels were summed.

  18. Study of the timing performance of micro-channel plate photomultiplier for use as an active layer in a shower maximum detector

    We continue the study of micro-channel plate photomultiplier (MCP-PMT) as the active element of a shower maximum (SM) detector. We present test beam results obtained with Photek 240 and Photonis XP85011 MCP-PMTs devices. For proton beams, we obtained a time resolution of 9.6 ps, representing a significant improvement over past results using the same time of flight system. For electron beams, the time resolution obtained for this new type of SM detector is measured to be at the level of 13 ps when we use Photek 240 as the active element of the SM. Using the Photonis XP85011 MCP-PMT as the active element of the SM, we performed time resolution measurements with pixel readout, and achieved a TR better than 30 ps, The pixel readout was observed to improve upon the TR compared to the case where the individual channels were summed

  19. A Study of Active Shielding Optimized for 1-80 keV Wide-Band X-ray Detector in Space

    Furuta, Yoshihiro; Hiraga, Junko S; Sasano, Makoto; Murakami, Hiroaki; Nakazawa, Kazuhiro

    2015-01-01

    Active shielding is an effective technique to reduce background signals in hard X-ray detectors and to enable observing darker sources with high sensitivity in space. Usually the main detector is covered with some shield detectors made of scintillator crystals such as BGO (Bi$_4$Ge$_3$O$_{12}$), and the background signals are filtered out using anti-coincidence among them. Japanese X-ray observing satellites "Suzaku" and "ASTRO-H" employed this technique in their hard X-ray instruments observing at > 10 keV. In the next generation X-ray satellites, such as the NGHXT proposal, a single hybrid detector is expected to cover both soft (1-10 keV) and hard (> 10 keV) X-rays for effectiveness. However, present active shielding is not optimized for the soft X-ray band, 1-10 keV. For example, Bi and Ge, which are contained in BGO, have their fluorescence emission lines around 10 keV. These lines appear in the background spectra obtained by ASTRO-H Hard X-ray Imager, which are non-negligible in its observation energy b...

  20. Detectors on base of scintillation structures for registration of volumetric activities of gaseous and liquid media gamma radiation

    Kadilin, V. V.; Yurov, V. N.; Ryabeva, E. V.; Samossadny, V. T.; Lupar, E. E.; Trofimov, Yu A.; Kolesnikov, S. V.; Chebishev, S. B.; Nebolsin, V. O.

    2016-02-01

    The main aim of this research is the development and prototyping of the ionizing radiation detectors for the diagnosis of the physical processes used for monitoring the radiation situation at the thermal or fast neutrons reactors. In this article we present the experimental verification of applicability of the scintillation detectors based on LaBr3(Ce) and YAlO3(Ce). The experimental studies of the gamma-ray detection with several designs of the crystal scintillation detectors in gas and liquid are considered. It was shown that the measurement range in the liquid medium at the duration of one measurement of 100 seconds for 137Cs equals from 3.79·102 Bq/l to 1.08·108 Bq/l for detector prototype based on YAlO3(Ce).

  1. Activity measurements of radioactive solutions by liquid scintillation counting and pressurized ionization chambers and Monte Carlo simulations of source-detector systems for metrology

    The research works 'Activity measurements of radioactive solutions by liquid scintillation and pressurized ionization chambers and Monte Carlo simulations of source-detector systems' was presented for the graduation: 'Habilitation a diriger des recherches'. The common thread of both themes liquid scintillation counting and pressurized ionization chambers lies in the improvement of the techniques of radionuclide activity measurement. Metrology of ionization radiation intervenes in numerous domains, in the research, in the industry including the environment and the health, which are subjects of constant concern for the world population these last years. In this big variety of applications answers a large number of radionuclides of diverse disintegration scheme and under varied physical forms. The presented works realized within the National Laboratory Henri Becquerel have for objective to assure detector calibration traceability and to improve the methods of activity measurements within the framework of research projects and development. The improvement of the primary and secondary activity measurement methods consists in perfecting the accuracy of the measurements in particular by a better knowledge of the parameters influencing the detector yield. The works of development dealing with liquid scintillation counting concern mainly the study of the response of liquid scintillators to low energy electrons as well as their linear absorption coefficients using synchrotron radiation. The research works on pressurized ionization chambers consist of the study of their response to photons and electrons by experimental measurements compared to the simulation of the source-detector system using Monte Carlo codes. Besides, the design of a new type of ionization chamber with variable pressure is presented. This new project was developed to guarantee the precision of the amount of activity injected into the patient within the framework of diagnosis examination

  2. A High-Speed, Event-Driven, Active Pixel Sensor Readout for Photon-Counting Microchannel Plate Detectors

    Kimble, Randy A.; Pain, Bedabrata; Norton, Timothy J.; Haas, J. Patrick; Oegerle, William R. (Technical Monitor)

    2002-01-01

    Silicon array readouts for microchannel plate intensifiers offer several attractive features. In this class of detector, the electron cloud output of the MCP intensifier is converted to visible light by a phosphor; that light is then fiber-optically coupled to the silicon array. In photon-counting mode, the resulting light splashes on the silicon array are recognized and centroided to fractional pixel accuracy by off-chip electronics. This process can result in very high (MCP-limited) spatial resolution while operating at a modest MCP gain (desirable for dynamic range and long term stability). The principal limitation of intensified CCD systems of this type is their severely limited local dynamic range, as accurate photon counting is achieved only if there are not overlapping event splashes within the frame time of the device. This problem can be ameliorated somewhat by processing events only in pre-selected windows of interest of by using an addressable charge injection device (CID) for the readout array. We are currently pursuing the development of an intriguing alternative readout concept based on using an event-driven CMOS Active Pixel Sensor. APS technology permits the incorporation of discriminator circuitry within each pixel. When coupled with suitable CMOS logic outside the array area, the discriminator circuitry can be used to trigger the readout of small sub-array windows only when and where an event splash has been detected, completely eliminating the local dynamic range problem, while achieving a high global count rate capability and maintaining high spatial resolution. We elaborate on this concept and present our progress toward implementing an event-driven APS readout.

  3. Development of a Standardised Readout System for Active Pixel Sensors in HV/HR-CMOS Technologies for ATLAS Inner Detector Upgrades

    The LHC Phase-II Upgrade results in new challenges for tracking detectors for example in terms of cost effectiveness, resolution and radiation hardness. Active Pixel Sensors in HV/HR-CMOS technologies show promising results coping with these challenges. In order to demonstrate the feasibility of hybrid modules with active CMOS sensors and readout chips for the future ATLAS Inner Tracker, ATLAS R and D activities have started. After introducing the basic concepts and the demonstrator program, the development of an ATLAS compatible readout system will be presented as well as tuning procedures and measurements with demonstrator modules to test the readout system

  4. Microfluidic Scintillation Detectors

    Microfluidic scintillation detectors are devices of recent introduction for the detection of high energy particles, developed within the EP-DT group at CERN. Most of the interest for such technology comes from the use of liquid scintillators, which entails the possibility of changing the active material in the detector, leading to an increased radiation resistance. This feature, together with the high spatial resolution and low thickness deriving from the microfabrication techniques used to manufacture such devices, is desirable not only in instrumentation for high energy physics experiments but also in medical detectors such as beam monitors for hadron therapy.

  5. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

    Zhao, C.; Konstantinidis, A. C.; Zheng, Y.; Anaxagoras, T.; Speller, R. D.; Kanicki, J.

    2015-12-01

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm-1 and a DQE of around 0.5 at spatial frequencies  CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered.

  6. Development of Blocked-Impurity-Band-Type Ge Detectors Fabricated with the Surface-Activated Wafer Bonding Method for Far-Infrared Astronomy

    Hanaoka, M.; Kaneda, H.; Oyabu, S.; Yamagishi, M.; Hattori, Y.; Ukai, S.; Shichi, K.; Wada, T.; Suzuki, T.; Watanabe, K.; Nagase, K.; Baba, S.; Kochi, C.

    2016-07-01

    We report the current status of the development of our new detectors for far-infrared (FIR) astronomy. We develop Blocked-Impurity-Band (BIB)-type Ge detectors to realize large-format compact arrays covering a wide FIR wavelength range up to 200 \\upmu m. We fabricated Ge junction devices of different physical parameters with a BIB-type structure, using the room temperature, surface-activated wafer bonding (SAB) method. We measured the absolute responsivity and the spectral response curve of each device at low temperatures, using an internal blackbody source in a cryostat and a Fourier transform spectrometer, respectively. The results show that the SAB Ge junction devices have significantly higher absolute responsivities and longer cut-off wavelengths of the spectral response than the conventional bulk Ge:Ga device. Based upon the results, we discuss the optimum parameters of SAB Ge junction devices for FIR detectors. We conclude that SAB Ge junction devices possess a promising applicability to next-generation FIR detectors covering wavelengths up to ˜ 200 \\upmu m with high responsivity. As a next step, we plan to fabricate a BIB-type Ge array device in combination with a low-power cryogenic readout integrated circuit.

  7. The effect of interface phonons on operating electron states in three-barrier resonant tunneling structure as an active region of quantum cascade detector

    M.V. Tkach; Ju.O. Seti; Grynyshyn, Y. B.; O.M. Voitsekhivska

    2014-01-01

    The Hamiltonian of electrons interacting with interface phonons in three-barrier resonant tunneling structure is established using the first principles within the models of effective mass and polarization continuum. Using the Green's functions method, the temperature shifts and decay rates of operating electron states are calculated depending on geometric design of three-barrier nano-structure GaAs/AlxGa1-xAs which is an active region of quantum cascade detector. It is established that indepe...

  8. Fiber optic detector

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  9. Metal Detectors.

    Harrington-Lueker, Donna

    1992-01-01

    Schools that count on metal detectors to stem the flow of weapons into the schools create a false sense of security. Recommendations include investing in personnel rather than hardware, cultivating the confidence of law-abiding students, and enforcing discipline. Metal detectors can be quite effective at afterschool events. (MLF)

  10. Gaseous detectors

    Fischer, Hans Gerhard

    1996-01-01

    Detector physics and operational aspects of gaseous detectors will be discussed. Topics such as ionization processes, gas amplification and its limitations, pulse formation and decoupling, related electronics constraints, operational stability and ageing phenomena will be touched with the aim at some quantitative understanding.

  11. Radiation-hard active pixel sensors for HL-LHC detector upgrades based on HV-CMOS technology

    Miucci, A.; Gonella, L.; Hemperek, T.; Hügging, F.; H. Krüger; Obermann, T.; N. Wermes; M. Garcia-Sciveres; Backhaus, M.; Capeans, M.; Feigl, S.; Nessi, M; Pernegger, H.(CERN, Geneva, Switzerland); Ristic, B.; Gonzalez-Sevilla, S

    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 ci...

  12. Advanced superconducting optical detectors

    We have investigated advanced superconducting optical and infrared detectors for their integration with superconductive active circuits. The detectors are based on ultra-thin NbN striplines. NbN is the material of choice for single photon optical and infrared detectors, as already demonstrated in the literature. The detectors so far proposed are based on conceptually simple, although difficult to realize, sub-micrometric meander type structures. Most applications of such detectors require some treatment of the signal generated, either as pulse shaping or signal amplification, to fully exploit the detection capabilities, such as sub-ns response time and proportional response. We have developed a room temperature process that, while preserving reasonable superconducting properties of NbN, allows a simple integration of the detectors in Nb-based circuits. Moreover we have developed a passivation technique, by using a protective AlN layer on top of the NbN one. The developed technology allows complex detector configurations, such as integrated RSFQ circuits or SQUID readout, to be relatively easily realized. The response of our NbN strip to photon irradiation will be presented

  13. ATLAS Detector Interface Group

    Mapelli, L

    Originally organised as a sub-system in the DAQ/EF-1 Prototype Project, the Detector Interface Group (DIG) was an information exchange channel between the Detector systems and the Data Acquisition to provide critical detector information for prototype design and detector integration. After the reorganisation of the Trigger/DAQ Project and of Technical Coordination, the necessity to provide an adequate context for integration of detectors with the Trigger and DAQ lead to organisation of the DIG as one of the activities of Technical Coordination. Such an organisation emphasises the ATLAS wide coordination of the Trigger and DAQ exploitation aspects, which go beyond the domain of the Trigger/DAQ project itself. As part of Technical Coordination, the DIG provides the natural environment for the common work of Trigger/DAQ and detector experts. A DIG forum for a wide discussion of all the detector and Trigger/DAQ integration issues. A more restricted DIG group for the practical organisation and implementation o...

  14. Multisensor mine detector for peacekeeping: improved landmine detector concept (ILDC)

    McFee, John E.; Carruthers, Al

    1996-05-01

    The Improved Landmine Detector Concept Project was initiated in Autumn 1994 to develop a prototype vehicle mounted mine detector for low metal content and nonmetallic mines for a peacekeeping role on roads. The system will consist of a teleoperated vehicle carrying a highly sensitive electromagnetic induction (EMI) detector, an infrared imager (IR), ground probing radar (GPR), and a thermal neutron activation (TNA) detector for confirmation. The IR, EMI and TNA detectors have been under test since 1995 and the GPR will be received in June 1996. Results of performance trials of the individual detectors are discussed. Various design configurations and their tradeoffs are discussed. Fusion of data from the detectors to reduce false alarm rate and increase probability of detection, a key element to the success of the system, is discussed. An advanced development model of the system is expected to be complete by Spring 1997.

  15. Application of the spatial efficiency e(~r) of a HpGe detector to determine the speci activity of radioactive material in cylindrical extended sources

    In the present work, the intrinsic efficiency for a high-resolution spectroscopy gamma system as a function of the source-detector position, i.e. (r), and the specific activity for a radioactive homogeneous extended source in cylindrical geometry, for an energy of 661.65 keV (137Cs), were determined. Mathematical expressions for the intrinsic spatial efficiency and the spe ci activity of a volumetric cylindrical sample were obtained from basic concepts of solid angle and gamma attenuation. In order to determine the intrinsic spatial e iency, a 137Cs source of known activity was positioned at difference source-detector position. This efficiency was used to establish the specific activity for different reference materials.This methodology allows us to determine the spe ci activity of radioactive species present in volumetric samples, such as soil, water and construction materials samples, without the direct use of reference materials for qu anti ation of radiation levels. The reference material was only used to validate the method. The advantage of this method is that allows specific activity determination without the need of making matrix effect corrections (shape and size of the sample, sample density, self-attenuation and moisture), which are the principal error sources in this type of measurement

  16. MUON DETECTOR

    F. Gasparini

    DT As announced in the previous Bulletin MU DT completed the installation of the vertical chambers of barrel wheels 0, +1 and +2. 242 DT and RPC stations are now installed in the negative barrel wheels. The missing 8 (4 in YB-1 and 4 in YB-2) chambers can be installed only after the lowering of the two wheels into the UX cavern, which is planned for the last quarter of the year. Cabling on the surface of the negative wheels was finished in May after some difficulties with RPC cables. The next step was to begin the final commissioning of the wheels with the final trigger and readout electronics. Priority was giv¬en to YB0 in order to check everything before the chambers were covered by cables and services of the inner detectors. Commissioning is not easy since it requires both activity on the central and positive wheels underground, as well as on the negative wheels still on the surface. The DT community is requested to commission the negative wheels on surface to cope with a possible lack of time a...

  17. Single gas chromatography method with nitrogen phosphorus detector for urinary cotinine determination in passive and active smokers

    Lusiane Malafatti

    2010-12-01

    Full Text Available Nicotine is a major addictive compound in cigarettes and is rapidly and extensively metabolized to several metabolites in humans, including urinary cotinine, considered a biomarker due to its high concentration compared to other metabolites. The aim of this study was to develop a single method for determination of urinary cotinine, in active and passive smokers, by gas chromatography with a nitrogen phosphorus detector (GC-NPD. Urine (5.0 mL was extracted with 1.0 mL of sodium hydroxide 5 mol L-1, 5.0 mL of chloroform, and lidocaine used as the internal standard. Injection volume was 1 μL in GC-NPD. Limit of quantification was 10 ng mL-1. Linearity was evaluated in the ranges 10-1000 ng mL-1 and 500-6000 ng mL-1, with determination coefficients of 0.9986 and 0.9952, respectively. Intra- and inter-assay standard relative deviations were lower than 14.2 %, while inaccuracy (bias was less than +11.9%. The efficiency of extraction was greater than 88.5%. Ruggedness was verified, according to Youden's test. Means of cotinine concentrations observed were 2,980 ng mL-1 for active smokers and 132 ng mL-1, for passive smokers. The results revealed that satisfactory chromatographic separation between the analyte and interferents was obtained with a ZB-1 column. This method is reliable, precise, linear and presented ruggedness in the range evaluated. The results suggest that it can be applied in routine analysis for passive and active smokers, since it is able to quantify a wide range of cotinine concentrations in urine.A nicotina é uma substância presente no cigarro capaz de causar dependência, sendo biotransformada em vários metabólitos nos seres humanos, dentre eles a cotinina urinária, que é considerada um indicador biológico de exposição à nicotina, devido a suas altas concentrações, comparado a outras matrizes. Assim, o objetivo deste estudo foi desenvolver um único método para determinação de cotinina urinária, em amostras de

  18. SMARTPIX, a photon-counting pixel detector for synchrotron applications based on Medipix3RX readout chip and active edge pixel sensors

    Photon-counting pixel detectors are now routinely used on synchrotron beamlines. Many applications benefit from their noiseless mode of operation, single-pixel point spread function and high frame rates. One of their drawbacks is a discontinuous detection area due to the space-consuming wirebonded connections of the readout chips. Moreover, charge sharing limits their efficiency and their energy discrimination capabilities. In order to overcome these issues the ESRF is developing SMARTPIX,a scalable and versatile pixel detector system with minimized dead areas and with energy resolving capabilities based on the MEDIPIX3RX readout chip. SMARTPIX exploits the through-silicon via technology implemented on MEDIPIX3RX, the active edge sensor processing developed in particular at ADVACAM, and the on-chip analog charge summing feature of MEDIPIX3RX. This article reports on system architecture, unit module structure, data acquisition electronics, target characteristics and applications

  19. SMARTPIX, a photon-counting pixel detector for synchrotron applications based on Medipix3RX readout chip and active edge pixel sensors

    Ponchut, C.; Collet, E.; Hervé, C.; Le Caer, T.; Cerrai, J.; Siron, L.; Dabin, Y.; Ribois, J. F.

    2015-01-01

    Photon-counting pixel detectors are now routinely used on synchrotron beamlines. Many applications benefit from their noiseless mode of operation, single-pixel point spread function and high frame rates. One of their drawbacks is a discontinuous detection area due to the space-consuming wirebonded connections of the readout chips. Moreover, charge sharing limits their efficiency and their energy discrimination capabilities. In order to overcome these issues the ESRF is developing SMARTPIX,a scalable and versatile pixel detector system with minimized dead areas and with energy resolving capabilities based on the MEDIPIX3RX readout chip. SMARTPIX exploits the through-silicon via technology implemented on MEDIPIX3RX, the active edge sensor processing developed in particular at ADVACAM, and the on-chip analog charge summing feature of MEDIPIX3RX. This article reports on system architecture, unit module structure, data acquisition electronics, target characteristics and applications.

  20. ABC 27-2 General bat activity measured with an ultrasound detector in a fragmented tropical landscape in Los Tuxtlas, Mexico

    Estrada, A.

    2004-12-01

    Full Text Available Bat tolerance to neotropical forest fragmentation may be related to ability by bats to use available habitats in the modified environmental matrix. This paper presents data on general bat activity (for three hours starting at dusk measured with an ultrasound detector in a fragmented landscape in the region of Los Tuxtlas, Mexico. Bat activity was measured in continuous forests, forests fragments, forest-pasture edges, forest corridors, linear strips of vegetation, citrus groves, pastures and the vegetation present in local villages. The highest bat activity rates were recorded in the villages, in the forest fragments and in linear strips of vegetation. The lowest activity rates were detected in pasture habitats. Data suggest that native and man-made arboreal vegetation may be important for sustaining bat activity in fragmented landscapes.

  1. The role of activator concentration and precipitate formation on optical and dosimetric properties of KCl:Eu{sup 2+} storage phosphor detectors

    Hansel, Rachael A.; Xiao, Zhiyan; Hu, Yanle; Green, Olga; Yang, Deshan; Harold Li, H. [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

    2013-09-15

    Purpose: The activator ion (Eu{sup 2+} in KCl:Eu{sup 2+}) plays an important role in the photostimulated luminescence (PSL) mechanism of storage phosphor radiation detectors. In order to design an accurate, effective, and robust detector, it is important to understand how the activator ion concentration affects the structure and, consequently, radiation detection properties of KCl:Eu{sup 2+}.Methods: Potassium chloride pellets were fabricated with various amounts of europium dopant (0.01–5.0 mol.% Eu{sup 2+}). Clinical radiation doses were given with a 6 MV linear accelerator. Radiation doses larger than 100 Gy were given with a {sup 137}Cs irradiator. Dose response curves, radiation hardness, and temporal signal stability were measured using a laboratory PSL readout system. The crystal structure of the material was studied using x ray diffraction and luminescence spectroscopy.Results: The most intense PSL signal was from samples with 1.0 mol.% Eu. However, samples with concentrations higher than 0.05 mol.% Eu exhibited significant degradation in PSL intensity for cumulated doses larger than 3000 Gy. Structural and luminescence spectroscopy showed clear evidence of precipitate phases within the KCl lattice, especially for high activator concentrations. Analysis of PL emission spectra showed that interactions between Eu-V{sub c} dipoles and Eu-V{sub c} trimers could explain trends in PSL sensitivity and radiation hardness observations.Conclusions: The concentration of the activator ion (Eu{sup 2+}) significantly affects radiation detection properties of the storage phosphor KCl:Eu{sup 2+}. An activator concentration between 0.01 and 0.05 mol.% Eu in KCl:Eu{sup 2+} storage phosphor detectors is recommended for linear dose response, good PSL sensitivity, predictable temporal stability, and high reusability for megavoltage radiation detection.

  2. MS Detectors

    Koppenaal, David W.; Barinaga, Charles J.; Denton, M Bonner B.; Sperline, Roger P.; Hieftje, Gary M.; Schilling, G. D.; Andrade, Francisco J.; Barnes IV., James H.

    2005-11-01

    Good eyesight is often taken for granted, a situation that everyone appreciates once vision begins to fade with age. New eyeglasses or contact lenses are traditional ways to improve vision, but recent new technology, i.e. LASIK laser eye surgery, provides a new and exciting means for marked vision restoration and improvement. In mass spectrometry, detectors are the 'eyes' of the MS instrument. These 'eyes' have also been taken for granted. New detectors and new technologies are likewise needed to correct, improve, and extend ion detection and hence, our 'chemical vision'. The purpose of this report is to review and assess current MS detector technology and to provide a glimpse towards future detector technologies. It is hoped that the report will also serve to motivate interest, prompt ideas, and inspire new visions for ion detection research.

  3. ALARA Review of the Activation/Repair of Fire Detectors in Zone Three at the 233-S Facility

    A formal as low as reasonably achievable (ALARA) review is required by BHI-SH-02, Vol. 1, Procedure 1.22, 'Planning Radiological Work', when radiological conditions exceed trigger levels. The level of contamination inside the viewing room meets this criterion. This ALARA review is for task instruction 1997-03-18-005-8.3.3 (mini task instruction to a living work package), 'Instructions for D ampersand D Support of Fire Detector Troubleshooting and Minor Maintenance Work at 233-S,' and DynCorp 2G-98-7207C, '233-S Reconnect Smoke Detectors Zone 3.' The Radiological Work Permit (RWP) request broke these two task instructions into four separate tasks. The four tasks identified in the RWP request were used to estimate airborne concentrations and the total exposure

  4. Measurement of thermal neutron distribution from a medical cyclotron using auto radiography with 23Na activation detector and medical imaging plate

    When the generated activity of 18F was 100 GBq, about 1015 neutrons are emitted by the nuclear reaction in target of the medical cyclotron. These neutrons induce activity in the cyclotron and the indoor concrete of the cyclotron room, and will contribute to the exposure of the staff maintaining the cyclotron. This paper describes the basic characteristics of the thermal neutron measurement method of 23Na activation detector by auto radiography (ARG) using the medical imaging plate (IP). Simple linear regression lines were able to describe the relationship between the scanner unit and the activity of 24Na. The optimal S value and exposure time of ARG method was found to be 1,000 and 24 hours. This method that uses the salt instead of gold foil allows hospitals to measure the thermal neutron fluencies easily at many locations for the radiation safety management of routine work and the decommissioning of the cyclotron facility. (author)

  5. Studies On Monolithic Active Pixel Sensors and Detector Performance for the Inner Tracking System Upgrade of ALICE

    Siddhanta, Sabyasachi

    2014-01-01

    ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC designed to study the physics of strongly interacting matter, and in particular the properties of the Quark-Gluon Plasma (QGP), using Pb-Pb collisions at unprecedented energy densities. During the first three years of operation, it has demonstrated very good capabilities for measurements at high energy Pb-Pb collisions. But there are certain measurements like high precision measurements o...

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

    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...

  7. Active filters study for electronic circuit associated at the lecture of signals coming from detectors with high particle rates

    In the case of detectors with high particle rates, the read out electronics has to be fast. The overall response of the chain to the detector signal has to be made short by using appropriate filtering. Hence, shortening filters are used for the detector signal tail, for the preamplifier integration time constant and for the transmission cable tail when used with fast signals. For exponential waveform shortening, the filter synthesis is easy: the signal pole is cancelled by the zero of the filter circuit response and replaced by a new pole. The filter is called a pole-zero. For a signal with a non exponential tail, there is no simple way to accomplish the filter synthesis. In this case, the same pole-zero filters are used, but the synthesis is done by using an approximation for the signal with: a fast component by a Dirac function and a slow component by an exponential function. We are able in this case to determine the characteristics of the filter as a function of the desired shortening, which depends on the gaussian filter width desired for the overall response

  8. 50 μm pixel pitch wafer-scale CMOS active pixel sensor x-ray detector for digital breast tomosynthesis

    Wafer-scale CMOS active pixel sensors (APSs) have been developed recently for x-ray imaging applications. The small pixel pitch and low noise are very promising properties for medical imaging applications such as digital breast tomosynthesis (DBT). In this work, we evaluated experimentally and through modeling the imaging properties of a 50 μm pixel pitch CMOS APS x-ray detector named DynAMITe (Dynamic Range Adjustable for Medical Imaging Technology). A modified cascaded system model was developed for CMOS APS x-ray detectors by taking into account the device nonlinear signal and noise properties. The imaging properties such as modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) were extracted from both measurements and the nonlinear cascaded system analysis. The results show that the DynAMITe x-ray detector achieves a high spatial resolution of 10 mm−1 and a DQE of around 0.5 at spatial frequencies  <1 mm−1. In addition, the modeling results were used to calculate the image signal-to-noise ratio (SNRi) of microcalcifications at various mean glandular dose (MGD). For an average breast (5 cm thickness, 50% glandular fraction), 165 μm microcalcifications can be distinguished at a MGD of 27% lower than the clinical value (∼1.3 mGy). To detect 100 μm microcalcifications, further optimizations of the CMOS APS x-ray detector, image aquisition geometry and image reconstruction techniques should be considered. (paper)

  9. Photon detectors

    Va`vra, J.

    1995-10-01

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF{sub 2} windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission.

  10. Photon detectors

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF2 windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission

  11. Commissioning the CMS pixel detector with Cosmic Rays

    Heyburn, Bernadette

    2009-01-01

    commissioning activities in the CMS pixel detector. Results from cosmic ray studies will be presented, in addition to results obtained from the integration of the pixel detector within the CMS detector and various calibration and alignment analyses.

  12. Design and testing of a unique active Compton-suppressed LaBr3(Ce) detector system for improved sensitivity assays of TRU in remote-handled TRU wastes

    The US Department of Energy's transuranic (TRU) waste inventory includes about 4,500 m3 of remote-handled TRU (RH-TRU) wastes composed of a variety of containerized waste forms having a contact surface dose rate that exceeds 2 mSv/hr (200 mrem/hr) containing waste materials with a total TRU concentration greater than 3700 Bq/g (100 nCi/g). As part of a research project to investigate the use of active Compton-suppressed room-temperature gamma-ray detectors for direct non-destructive quantification of the TRU content of these RH-TRU wastes, we have designed and purchased a unique detector system using a LaBr3(Ce) primary detector and a NaI(Tl) suppression mantle. The LaBr3(Ce) primary detector is a cylindrical unit ∼25 mm in diameter by 76 mm long viewed by a 38 mm diameter photomultiplier. The NaI(Tl) suppression mantle (secondary detector) is 175 mm by 175 mm with a center well that accommodates the primary detector. An important feature of this arrangement is the lack of any 'can' between the primary and secondary detectors. These primary and secondary detectors are optically isolated by a thin layer (.003') of aluminized kapton, but the hermetic seal and thus the aluminum can surrounds the outer boundary of the detector system envelope. The hermetic seal at the primary detector PMT is at the PMT wall. This arrangement virtually eliminates the 'dead' material between the primary and secondary detectors, a feature that preliminary modeling indicated would substantially improve the Compton suppression capability of this device. This paper presents both the expected performance of this unit determined from modeling with MCNPX, and the performance measured in our laboratory with radioactive sources

  13. Time-resolved dose evaluation in an X- and gamma-ray irradiated silver-activated glass detector for three-dimensional imaging applications

    Ag-activated phosphate glass based on the radiophotoluminescence (RPL) phenomenon has been used as the most commonly known RPL material and as an accumulated-type passive detector. In this work, the transient-state evaluation of the dose distributions achieved by X- and gamma-ray irradiations within the Ag-activated phosphate glass was performed using a time-resolved technique for the first time. Specifically, the blue RPL intensity ascribed to the electron-trapped Ag0 centres as a function of the depth at the vicinity of the surface was investigated for different types of radiation and a wide range of energies. In addition, the dose distributions at each layer within the glass confirmed by the time-resolved measurement were compared with those reconstructed by a disk-type transparent glass detector based on the blue RPL with a diameter of 100 mm. - Highlights: • The time-resolved dose evaluation of Ag-activated glass was performed. • The RPL intensity as a function of the depth was investigated for X- and gamma-rays. • The origin and mechanisms for the RPL enhancement in the near-surface layers were discussed

  14. The DELPHI Detector (DEtector with Lepton Photon and Hadron Identification)

    Crawley, B; Munich, K; Mckay, R; Matorras, F; Joram, C; Malychev, V; Behrmann, A; Van dam, P; Drees, J K; Stocchi, A; Adam, W; Booth, P; Bilenki, M; Rosenberg, E I; Morton, G; Rames, J; Hahn, S; Cosme, G; Ventura, L; Marco, J; Tortosa martinez, P; Monge silvestri, R; Moreno, S; Phillips, H; Alekseev, G; Boudinov, E; Martinez rivero, C; Gitarskiy, L; Davenport, M; De clercq, C; Firestone, A; Myagkov, A; Belous, K; Haider, S; Hamilton, K M; Lamsa, J; Rahmani, M H; Malek, A; Hughes, G J; Peralta, L; Carroll, L; Fuster verdu, J A; Cossutti, F; Gorn, L; Yi, J I; Bertrand, D; Myatt, G; Richard, F; Shapkin, M; Hahn, F; Ferrer soria, A; Reinhardt, R; Renton, P; Sekulin, R; Timmermans, J; Baillon, P

    2002-01-01

    % DELPHI The DELPHI Detector (Detector with Lepton Photon and Hadron Identification) \\\\ \\\\DELPHI is a general purpose detector for physics at LEP on and above the Z$^0$, offering three-dimensional information on curvature and energy deposition with fine spatial granularity as well as identification of leptons and hadrons over most of the solid angle. A superconducting coil provides a 1.2~T solenoidal field of high uniformity. Tracking relies on the silicon vertex detector, the inner detector, the Time Projection Chamber (TPC), the outer detector and forward drift chambers. Electromagnetic showers are measured in the barrel with high granularity by the High Density Projection Chamber (HPC) and in the endcaps by $ 1 ^0 $~x~$ 1 ^0 $ projective towers composed of lead glass as active material and phototriode read-out. Hadron identification is provided mainly by liquid and gas Ring Imaging Counters (RICH). The instrumented magnet yoke serves for hadron calorimetry and as filter for muons, which are identified in t...

  15. Calorimeter detectors

    de Barbaro, P; The ATLAS collaboration

    2013-01-01

    Although the instantaneous and integrated luminosity in HL-LHC will be far higher than the LHC detectors were originally designed for, the Barrel calorimeters of the four experiments are expected to continue to perform well  throughout the Phase II program. The conditions for the End-Cap calorimeters are far more challenging and whilst some detectors will require relatively modest changes, others require far more substantial upgrades. We present the results of longevity and performance studies for the calorimeter systems of the four main LHC experiments and outline the upgrade options under consideration. We include a discussion of the R&D required to make the final technology choices for the upgraded detectors.

  16. Pixel detectors

    Passmore, M S

    2001-01-01

    positions on the detector. The loss of secondary electrons follows the profile of the detector and increases with higher energy ions. studies of the spatial resolution predict a value of 5.3 lp/mm. The image noise in photon counting systems is investigated theoretically and experimentally and is shown to be given by Poisson statistics. The rate capability of the LAD1 was measured to be 250 kHz per pixel. Theoretical and experimental studies of the difference in contrast for ideal charge integrating and photon counting imaging systems were carried out. It is shown that the contrast differs and that for the conventional definition (contrast = (background - signal)/background) the photon counting device will, in some cases, always give a better contrast than the integrating system. Simulations in MEDICI are combined with analytical calculations to investigate charge collection efficiencies (CCE) in semiconductor detectors. Different pixel sizes and biasing conditions are considered. The results show charge shari...

  17. MAMA Detector

    Bowyer, Stuart

    1998-01-01

    Work carried out under this grant led to fundamental discoveries and over one hundred publications in the scientific literature. Fundamental developments in instrumentation were made including all the instrumentation on the EUVE satellite, the invention of a whole new type of grazing instrument spectrometer and the development of fundamentally new photon counting detectors including the Wedge and Strip used on EUVE and many other missions and the Time Delay detector used on OREFUS and FUSE. The Wedge and Strip and Time Delay detectors were developed under this grant for less than two million dollars and have been used in numerous missions most recently for the FUSE mission. In addition, a fundamentally new type of diffuse spectrometer has been developed under this grant which has been used in instrumentation on the MMSAT spacecraft and the Lewis spacecraft. Plans are underway to use this instrumentation on several other missions as well.

  18. Ionization detector

    The objects of the invention are, first, to provide an ionization detector having a three chamber structure characterised by a built-in feedback path that regeneratively stabilizes the operating point of the detector. Secondly, to provide a specially designed chamber construction including electrodes shaped so as to enhance the efficiency of the chamber and reduce ion recombination. The ionization chamber described has a chamber structure with a first closed chamber and a second chamber able to receive gases from outside. These two chambers have a common boundary including a common electrode. One electrode associated with the second chamber, and one within the first chamber, define a third chamber within the first chamber allowing an ionization path between. A radioactive source provides ionizing radiation for all three chambers and establishes an ionization current. There is a detector coupled to the common electrode for detecting changes in this current. (U.K.)

  19. ALICE TPC Upgrade Activities for LHC Run 3 and Beyond: "SAMPA ASIC Tests with GEM Detector Prototype"

    Engeseth, Kristian Philip

    2015-01-01

    The Time Projection Chamber (TPC) signal readout of the ALICE detector is being upgraded to accommodate the higher collision rates and -energies during LHC Run 3 in 2018. Due to the increased collision rates, the TPC drift time of about 100 μs will be 5 times longer than the average time between interactions, rendering the presently employed gating of the TPC wire-chambers insufficient. Therefore, a Gas Electron Multiplier (GEM) based system will be replacing the wire-chambers. In addition, t...

  20. Detector simulation for the SSC

    Detector simulation activities for SSC detector designs are described. Topics include the extensive work to date using existing programs. In addition, the several efforts to extend the capabilities of today's programs are described, as the practical and experimental use of new computing platforms for simulation. Finally, progress in the field is compared with the recommendations of the first workshop in this series in 1987

  1. BES detector

    The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e+e- annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector. (orig.)

  2. Radiation damage of germanium detectors

    Pehl, R. H.

    1978-01-01

    Energetic particles can produce interstitial-vacancy pairs in a crystal by knocking the atoms from their normal positions. Detectors are unique among semiconductor devices in depending on very low concentrations of electrically active impurities, and also on efficient transport of holes and electrons over relatively large distances. Because the dense regions of damage produced by energetic particles may result in donors and/or acceptors, and also provide trapping sites for holes and electrons, detectors are very sensitive to radiation damage. In addition to these effects occurring within the detector, radiation may also change the characteristics of the exposed surfaces causing unpredictable effects on the detector leakage current. Radiation-induced surface degradation has rarely, if ever, been observed for germanium detectors. The possibility of minimizing hole trapping in charge collection by the use of a high-purity germanium coaxial detector configured with the p (+) contact on the coaxial periphery is discussed.

  3. Ionic smoke detectors

    2002-01-01

    Ionic smoke detectors are products incorporating radioactive material. This article summarises the process for their commercialization and marketing, and how the activity is controlled, according to regulations establishing strict design and production requisites to guarantee the absence of radiological risk associated both with their use and their final handling as conventional waste. (Author)

  4. SiC Schottky Diode Detectors for Measurement of Actinide Concentrations from Alpha Activities in Molten Salt Electrolyte

    In this project, we have designed a 4H-SiC Schottky diode detector device in order to monitor actinide concentrations in extreme environments, such as present in pyroprocessing of spent fuel. For the first time, we have demonstrated high temperature operation of such a device up to 500 °C in successfully detecting alpha particles. We have used Am-241 as an alpha source for our laboratory experiments. Along with the experiments, we have developed a multiscale model to study the phenomena controlling the device behavior and to be able to predict the device performance. Our multiscale model consists of ab initio modeling to understand defect energetics and their effect on electronic structure and carrier mobility in the material. Further, we have developed the basis for a damage evolution model incorporating the outputs from ab initio model in order to predict respective defect concentrations in the device material. Finally, a fully equipped TCAD-based device model has been developed to study the phenomena controlling the device behavior. Using this model, we have proven our concept that the detector is capable of performing alpha detection in a salt bath with the mixtures of actinides present in a pyroprocessing environment.

  5. SiC Schottky Diode Detectors for Measurement of Actinide Concentrations from Alpha Activities in Molten Salt Electrolyte

    Windl, Wolfgang [The Ohio State Univ., Columbus, OH (United States); Blue, Thomas [The Ohio State Univ., Columbus, OH (United States)

    2013-01-28

    In this project, we have designed a 4H-SiC Schottky diode detector device in order to monitor actinide concentrations in extreme environments, such as present in pyroprocessing of spent fuel. For the first time, we have demonstrated high temperature operation of such a device up to 500 °C in successfully detecting alpha particles. We have used Am-241 as an alpha source for our laboratory experiments. Along with the experiments, we have developed a multiscale model to study the phenomena controlling the device behavior and to be able to predict the device performance. Our multiscale model consists of ab initio modeling to understand defect energetics and their effect on electronic structure and carrier mobility in the material. Further, we have developed the basis for a damage evolution model incorporating the outputs from ab initio model in order to predict respective defect concentrations in the device material. Finally, a fully equipped TCAD-based device model has been developed to study the phenomena controlling the device behavior. Using this model, we have proven our concept that the detector is capable of performing alpha detection in a salt bath with the mixtures of actinides present in a pyroprocessing environment.

  6. The CLIC Vertex Detector

    Dannheim, D.

    2015-03-01

    The precision physics needs at TeV-scale linear electron-positron colliders (ILC and CLIC) require a vertex-detector system with excellent flavour-tagging capabilities through a measurement of displaced vertices. This is essential, for example, for an explicit measurement of the Higgs decays to pairs of b-quarks, c-quarks and gluons. Efficient identification of top quarks in the decay t → Wb will give access to the ttH-coupling measurement. In addition to those requirements driven by physics arguments, the CLIC bunch structure calls for hit timing at the few-ns level. As a result, the CLIC vertex-detector system needs to have excellent spatial resolution, full geometrical coverage extending to low polar angles, extremely low material budget, low occupancy facilitated by time-tagging, and sufficient heat removal from sensors and readout. These considerations challenge current technological limits. A detector concept based on hybrid pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin planar or active HV-CMOS sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. This contribution reviews the requirements and design optimisation for the CLIC vertex detector and gives an overview of recent R&D achievements in the domains of sensors, readout and detector integration.

  7. The CLIC Vertex Detector

    The precision physics needs at TeV-scale linear electron-positron colliders (ILC and CLIC) require a vertex-detector system with excellent flavour-tagging capabilities through a measurement of displaced vertices. This is essential, for example, for an explicit measurement of the Higgs decays to pairs of b-quarks, c-quarks and gluons. Efficient identification of top quarks in the decay t → Wb will give access to the ttH-coupling measurement. In addition to those requirements driven by physics arguments, the CLIC bunch structure calls for hit timing at the few-ns level. As a result, the CLIC vertex-detector system needs to have excellent spatial resolution, full geometrical coverage extending to low polar angles, extremely low material budget, low occupancy facilitated by time-tagging, and sufficient heat removal from sensors and readout. These considerations challenge current technological limits. A detector concept based on hybrid pixel-detector technology is under development for the CLIC vertex detector. It comprises fast, low-power and small-pitch readout ASICs implemented in 65 nm CMOS technology (CLICpix) coupled to ultra-thin planar or active HV-CMOS sensors via low-mass interconnects. The power dissipation of the readout chips is reduced by means of power pulsing, allowing for a cooling system based on forced gas flow. This contribution reviews the requirements and design optimisation for the CLIC vertex detector and gives an overview of recent R and D achievements in the domains of sensors, readout and detector integration

  8. A Method To Directly Analyze The Activity Of 238U Nuclide In An HPGe Detector Based GAMMA Spectrometer Using MCNP5 Code

    One of the direct analysis methods of the activity of 238U nuclide in an HPGe detector based gamma spectrometer is to measure the 63.3 keV gamma ray emitted from 234Th nuclide. The advantage of this method is to overcome the difficulty of sample sealing in the analysis of 226Ra nuclide. However for the samples of low activity as environmental ones, they must have large masses and volumes. Then another difficulty appears relating with the significant self-absorption effect of this low energy gamma ray in the sample. This effect depends on the sample geometry, density and chemical composition. The present work suggests a method to correct the self-absorption effect by applying the Monte Carlo MCNP5 code. The sample containers used in this study have cylindrical and Marinelli forms with the sample masses of hundreds grams and sample volumes of hundreds cm3. (author)

  9. Laboratory and Field Testing of Commercially Available Detectors for the Identification of Chemicals of Interest in the Nuclear Fuel Cycle for the Detection of Undeclared Activities

    Carla Miller; Mary Adamic; Stacey Barker; Barry Siskind; Joe Brady; Warren Stern; Heidi Smartt; Mike McDaniel; Mike Stern; Rollin Lakis

    2014-07-01

    Traditionally, IAEA inspectors have focused on the detection of nuclear indicators as part of infield inspection activities. The ability to rapidly detect and identify chemical as well as nuclear signatures can increase the ability of IAEA inspectors to detect undeclared activities at a site. Identification of chemical indicators have been limited to use in the analysis of environmental samples. Although IAEA analytical laboratories are highly effective, environmental sample processing does not allow for immediate or real-time results to an IAEA inspector at a facility. During a complementary access inspection, under the Additional Protocol, the use of fieldable technologies that can quickly provide accurate information on chemicals that may be indicative of undeclared activities can increase the ability of IAEA to effectively and efficiently complete their mission. The Complementary Access Working Group (CAWG) is a multi-laboratory team with members from Brookhaven National Laboratory, Idaho National Laboratory, Los Alamos National Laboratory, and Sandia National Laboratory. The team identified chemicals at each stage of the nuclear fuel cycle that may provide IAEA inspectors with indications that proliferation activities may be occurring. The group eliminated all indicators related to equipment, technology and training, developing a list of by-products/effluents, non-nuclear materials, nuclear materials, and other observables. These proliferation indicators were prioritized based on detectability from a conduct of operations (CONOPS) perspective of a CA inspection (for example, whether an inspector actually can access the S&O or whether it is in process with no physical access), and the IAEA’s interest in the detection technology in conjunction with radiation detectors. The list was consolidated to general categories (nuclear materials from a chemical detection technique, inorganic chemicals, organic chemicals, halogens, and miscellaneous materials). The team

  10. Neutron detector

    Stephan, Andrew C.; Jardret; Vincent D.

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  11. Particle detectors

    Joram, Christian

    1998-01-01

    The lecture series will present and overview of the basic techniques and underlying physical principles of particle detectors, applied to current and future high energy physics experiments. Illustrating examples, mainly from the field of collider experiments, will demonstrate the performance and limitations of the various techniques. After and introduction we shall concentrate on particle tracking. Wire chambers, drift chambers, micro gaseous tracking devices and solid state trackers will be discussed. It follows and overview of scintillators, photon detection, fiber tracking and nuclear emulsions. One lecture will deal with the various techniques of calorimetry. Finally we shall focus on methods developed for particle identification. These comprise specific energy loss, time of flight Cherenkov and transition radiation detectors.

  12. A probe for neutron activation analysis in a drill hole using 252Cf, and a Ge(Li) detector cooled by a melting cryogen

    Tanner, A.B.; Moxham, R.M.; Senftle, F.E.; Baicker, J.A.

    1972-01-01

    A sonde has been built for high-resolution measurement of natural or neutron-induced gamma rays in boreholes. The sonde is 7.3 cm in diameter and about 2.2 m in length and weighs about 16 kg. The lithium-compensated germanium semiconductor detector is stabilized at -185 to -188??C for as much as ten hours by a cryostatic reservoir containing melting propane. During periods when the sonde is not in use the propane is kept frozen by a gravity-fed trickle of liquid nitrogen from a reservoir temporarily attached to the cryostat section. A 252Cf source, shielded from the detector, may be placed in the bottom section of the sonde for anlysis by measurement of neutron-activation or neutron-capture gamma rays. Stability of the cryostat with changing hydrostatic pressure, absence of vibration, lack of need for power to the cryostat during operation, and freedom of orientation make the method desirable for borehole, undersea, space, and some laboratory applications. ?? 1972.

  13. A Measurement of the W/Z Cross Section Ratio as a Function of Hadronic Activity with the ATLAS Detector

    Meade, Andrew Robert; Willocq, Stephane; Donoghue, John

    Hadronic collisions at the LHC at CERN probe particle interactions at the highest energy scale of any experiment to date. We present a research program measuring Rjet = &sigmaWBR(W&rarr&mu&nu) / (&sigmaZBR(Z&rarr&mu&mu)) as a function of a number of hadronic variables. The measurements are performed with the ATLAS detector at the LHC, using the 2011 data set, consisting of 4.64 fb-1 of pp collisions at a center of mass energy of 7 TeV. This measurement is a robust way to test the Standard Model and the modeling of perturbative QCD, and is sensitive to a wide variety of possible new physics in events with high jet ET, including some variations of Supersymmetry. By taking the ratio of W/Z production, a large number of systematic uncertainties cancel, including those associated with luminosity, jet energy scale and resolution, and many theoretical uncertainties. The measurement of Rjet is performed as a function of the pT and rapidity of the 1st-4th leading jet, ST, HT, and a num...

  14. Study of environmental natural gamma radiation dose and activity of uranium-238, thorium-232 using NaI (Tl) scintillation detector

    Exposure to ionizing radiation from natural sources is a continuous and unavoidable feature of life-systems on the earth. The environmental effective gamma radiation dose from terrestrial and cosmic radiation at height one foot above the earth's surface in open atmosphere has been measured at twenty different places in Sindhudurg district of Maharashtra state by using 2x2 NaI (Tl) scintillation detector. The activity of 238U and 232Th has been measured using gamma ray spectroscopy. The effective gamma radiation dose at different locations varies between, 0.286 to 0.804 mS/y, with an average value 0.512 mSv/y. The 238U activity varies from 0.466 KBq/m2 to 1.133 KBq/m2 with mean value of 0.684 KBq/m2. The 232Th activity varies from 0.552 KBq/m2 to 1.267 KBq/m2 with mean 0.8682 KBq/m2. The 238U to 232Th activity ratio varies from 0.494 to 1.47 with mean 0.898. (author)

  15. MUON DETECTORS: RPC

    P. Paolucci

    2012-01-01

    The RPC system is operating with a very high uptime, an average chamber efficiency of about 95% and an average cluster size around 1.8. The average number of active channels is 97.7%. Eight chambers are disconnected and forty are working in single-gap mode due to high-voltage problems. The total luminosity lost due to RPCs in 2012 is 88.46 pb–1. One of the main goals of 2012 was to improve the stability of the endcap trigger that is strongly correlated to the performances of the detector, due to the 3-out-3 trigger logic. At beginning of 2011 the instability of the detector efficiency was about 10%. Detailed studies found that this was mainly due to the strong correlation between the performance of the detector and the atmospheric pressure (P). Figure XXY shows the linear correlation between the average cluster size of the endcap chamber versus P. This effect is expected for gaseous detectors and can be reduced by correcting the applied high-voltage working point (HVapp) according to the followi...

  16. Salt bridges overlapping the gonadotropin-releasing hormone receptor agonist binding site reveal a coincidence detector for G protein-coupled receptor activation.

    Janovick, Jo Ann; Pogozheva, Irina D; Mosberg, Henry I; Conn, P Michael

    2011-08-01

    G protein-coupled receptors (GPCRs) play central roles in most physiological functions, and mutations in them cause heritable diseases. Whereas crystal structures provide details about the structure of GPCRs, there is little information that identifies structural features that permit receptors to pass the cellular quality control system or are involved in transition from the ground state to the ligand-activated state. The gonadotropin-releasing hormone receptor (GnRHR), because of its small size among GPCRs, is amenable to molecular biological approaches and to computer modeling. These techniques and interspecies comparisons are used to identify structural features that are important for both intracellular trafficking and GnRHR activation yet distinguish between these processes. Our model features two salt (Arg(38)-Asp(98) and Glu(90)-Lys(121)) and two disulfide (Cys(14)-Cys(200) and Cys(114)-Cys(196)) bridges, all of which are required for the human GnRHR to traffic to the plasma membrane. This study reveals that both constitutive and ligand-induced activation are associated with a "coincidence detector" that occurs when an agonist binds. The observed constitutive activation of receptors lacking Glu(90)-Lys(121), but not Arg(38)-Asp(98) ionic bridge, suggests that the role of the former connection is holding the receptor in the inactive conformation. Both the aromatic ring and hydroxyl group of Tyr(284) and the hydrogen bonding of Ser(217) are important for efficient receptor activation. Our modeling results, supported by the observed influence of Lys(191) from extracellular loop 2 (EL2) and a four-residue motif surrounding this loop on ligand binding and receptor activation, suggest that the positioning of EL2 within the seven-α-helical bundle regulates receptor stability, proper trafficking, and function. PMID:21527534

  17. Particle detectors

    Hilke, Hans Jürgen; CERN. Geneva

    1991-01-01

    Lecture 5: Detector characteristics: ALEPH Experiment cut through the devices and events - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operartion and a few ideas on the future performance. Lecture 4-pt. b Following the Scintillators. Lecture 4-pt. a : Scintillators - Used for: -Timing (TOF, Trigger) - Energy Measurement (Calorimeters) - Tracking (Fibres) Basic scintillation processes- Inorganic Scintillators - Organic Scintil - Discuss the principles of the main techniques applied to particle detection ( including front-end electronics), the construction and performance of some of the devices presently in operation and a fiew ideas on future developpement session 3 - part. b Following Calorimeters lecture 3-pt. a Calorimeters - determine energy E by total absorption of charged or neutral particles - fraction of E is transformed into measurable quantities - try to acheive sig...

  18. Antimicrobial activity of Marcetia DC species (Melastomataceae and analysis of its flavonoids by reverse phase-high performance liquid chromatography coupled-diode array detector

    Tonny Cley Campos Leite

    2012-01-01

    Full Text Available Background: Marcetia genera currently comprises 29 species, with approximately 90% inhabiting Bahia (Brazil, and most are endemic to the highlands of the Chapada Diamantina (Bahia. Among the species, only M. taxifolia (A.St.-Hil. DC. populates Brazil (state of Roraima to Paranα and also Venezuela, Colombia, and Guyana. Objective: This work evaluated the antimicrobial activity of hexane, ethyl acetate, and methanol extracts of three species of Marcetia (Marcetia canescens Naud., M. macrophylla Wurdack, and M. taxifolia A.StHil against several microorganism. In addition, the flavonoids were analyzed in extracts by HPLC-DAD. Materials and methods: The tests were made using Gram-positive (three strains of Staphylococcus aureus and Gram-negative (two strains of Escherichia coli, a strain of Pseudomonas aeruginosa and another of Salmonella choleraesius bacteria resistant and nonresistant to antibiotics and yeasts (two strains of Candida albicans and one of C. parapsilosis by the disk diffusion method. Solid-phase extraction (SPE was performed on the above extracts to isolate flavonoids, which were subsequently analyzed by high performance liquid chromatography coupled diode array detector (HPLC-DAD. Results: Results showed that extracts inhibited the Gram-positive bacteria and yeast. The hexane extracts possessed the lowest activity, while the ethyl acetate and methanolic extracts were more active. Conclusion: Marcetia taxifolia was more effective (active against 10 microorganisms studied, and only its methanol extract inhibited Gram-negative bacteria (P. aeruginosa and S. choleraesius. SPE and HPLC-DAD analysis showed that M. canescens and M. macrophylla contain glycosylated flavonoids, while the majority of extracts from M. taxifolia were aglycone flavonoids.

  19. Silicon pad detectors for a simple tracking system and multiplicity detectors creation

    Silicon pad detectors are working at room temperatures, what is very convenient for creation of simple tracking system and multiplicity detectors. Silicon pad detectors are studied to create a compact detecting systems for active beam collimation and for gamma-radiation multiplicity measurements. The registration efficiency and spectral distributions of gamma-radiation and electrons were studied using isotope radiation sources. The silicon pad detectors were designed at NSC 'KIPT'

  20. Measure of thermal neutron flux in the IPEN/MB-01 reactor using {sup 197} Au wire activation detectors; Medida do fluxo de neutrons termicos do reator IPEN/MB-01 com detectores de ativacao de fios de {sup 197} Au

    Marques, Andre Luis Ferreira

    1995-12-31

    This dissertation has aimed at developing a neutron flux measurement technique by means of detectors activation analysis. The main task of this work was the implementation of this thermal neutron flux measurement technique, using gold wires as activation detectors in the IPEN/MB-01 reactor core. The neutron thermal flux spatial distribution was obtained by gold wire activation technique, with wire diameters of 0.125 mm and 0.250 mm in seven selected reactor experimental channels. The values of thermal flux were about 10{sup 9} neutrons/cm{sup 2}.s. This experiment has been the first one conducted with gold wires in the IPEN/MB-01 reactor, being this technique implemented for use by experiments in flux mapping of the core 73 refs., 60 figs., 31 tabs.

  1. First use of a high-sensitivity active pixel sensor array as a detector for electron microscopy

    Xuong, Nguyen-Huu; Milazzo, Anna-Clare; LeBlanc, Philippe; Duttweiler, Fred; Bouwer, James; Peltier, Steve; Ellisman, Mark; Denes, Peter; Bieser, Fred; Matis, Howard S.; Wieman, Howard; Kleinfelder, Stuart

    2004-06-01

    There is an urgent need to replace film and CCD cameras as recording instruments for transmission electron microscopy (TEM). Film is too cumbersome to process and CCD cameras have low resolution, marginal to poor signal-to-noise ratio for single electron detection and high spatial distortion. To find a replacement device, we have tested a high sensitivity active pixel sensor (APS) array currently being developed for nuclear physics. The tests were done at 120 keV in a JEOL 1200 electron microscope. At this energy, each electron produced on average a signal-tonoise ratio about 20/1. The spatial resolution was also excellent with the full width at half maximum (FWHM) about 20 microns. Since it is very radiation tolerant and has almost no spatial distortion, the above tests showed that a high sensitivity CMOS APS array holds great promise as a direct detection device for electron microscopy.

  2. Direct determination of GSK-3β activity and inhibition by UHPLC-UV-vis diode arrays detector (DAD).

    D'Urzo, Annalisa; De Simone, Angela; Fiori, Jessica; Naldi, Marina; Milelli, Andrea; Andrisano, Vincenza

    2016-05-30

    Altered GSK-3β activity can contribute to a number of pathological processes including Alzheimer's disease (AD). Indeed, GSK-3β catalyzes the hyperphosphorylation of tau protein by transferring a phosphate moiety from ATP to the protein substrate serine residue causing the formation of the toxic insoluble neurofibrillary tangles; for this reason it represents a key target for the development of new therapeutic agents for AD treatment. Herein we describe a new selective UHPLC methodology developed for the direct characterization of GSK-3β kinase activity and for the determination of its inhibition, which could be crucial in AD drug discovery. The UHPLC-UV (DAD) based method was validated for the very fast determination of ATP as reactant and ADP as product, and applied for the analysis of the enzymatic reaction between a phosphate primed peptide substrate (GSM), resembling tau protein sequence, ATP and GSK-3β, with/without inhibitors. Analysis time was ten times improved, when compared with previously published chromatographic methods. The method was also validated by determining enzyme reaction kinetic constants (KM and vmax) for GSM and ATP and by analyzing well known GSK-3β inhibitors. Inhibition potency (IC50) values for SB-415286 (81±6nM) and for Tideglusib (251±17nM), found by the newly developed UHPLC method, were in good agreement with the luminescence method taken as independent reference method. Further on, the UHPLC method was applied to the elucidation of Tideglusib mechanism of action by determining its inhibition constants (Ki). In agreement with literature data, Tideglusib resulted a GSM competitive inhibitor, whereas SB-415286 was found inhibiting GSK-3β in an ATP competitive manner. This method was applied to the determination of the potency of a new lead compound and was found potentially scalable to inhibitor screening of large compounds collections. PMID:26942334

  3. The HERMES Recoil Detector

    Yu, Weilin [II. Physikalisches Institut, JLU Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

    2008-07-01

    The HERMES Collaboration at HERA constructed and installed a new Recoil Detector to upgrade the existed spectrometer. This detector is designed to measure recoil protons in hard exclusive processes which provide access to the orbital angular momentum of quarks. The Recoil Detector consists of a silicon detector surrounding the target cell inside the beam vacuum, a scintillating fiber tracker and a photon detector. All three detectors are located inside a solenoidal magnet which provides a 1 T longitudinal magnetic field. The Recoil Detector was installed in January 2006 and data taking lasted until the end of HERA operation in June 2007. Results on the detector performance will be presented here.

  4. Improved germanium well detectors

    Germanium well detectors with metal surface barrier contact are comparable for general use with conventional germanium coaxial detectors. They offer very high sensitivity, the highest presently available

  5. A simple and rapid method for measuring α-D-phosphohexomutases activity by using anion-exchange chromatography coupled with an electrochemical detector.

    Jia, Xiaochen; Kang, Jian; Yin, Heng

    2016-01-01

    The interconversion of hexose-6-phosphate and hexose-1-phosphate can be directly analyzed by high-performance anion-exchange chromatography coupled with an electrochemical detector (HPAEC-PAD). Thus, this method can be used to measure the activities of N-acetylglucosamine-phosphate mutase (AGM), glucosamine-phosphate mutase (GlmM) and phosphoglucomutase (PGM), which are the members of α-D-phosphohexomutases superfamily. The detection limits were extremely low as 2.747 pmol, 1.365 pmol, 0.512 pmol, 0.415 pmol, 1.486 pmol and 0.868 pmol for N-acetylglucosamine-1-phosphate (GlcNAc-1-P), N-acetylglucosamine-6-phosphate (GlcNAc-6-P), glucosamine-1-phosphate (GlcN-1-P), glucosamine-6-phosphate (GlcN-6-P), glucose-1-phosphate (Glc-1-P) and glucose-6-phosphate (Glc-6-P), respectively. By employing HPAEC-PAD, activities of AtAGM (AGM from Arabidopsis thaliana) on these six phosphohexoses can be detected. The Km of AtAGM on Glc-1-P determined by HPAEC-PAD was 679.18 ± 156.40 µM, which is comparable with the Km of 707.09 ± 170.36 µM detected by traditional coupled assay. Moreover, the activity of MtGlmM (GlmM from Mycobacterium tuberculosis) on GlcN-6-P tested by HPAEC-PAD was 7493.40 ± 309.12 nmol∕min ⋅ mg, which is much higher than 288.97 ± 35.28 nmol∕min ⋅ mg obtained by the traditional coupled assay. Accordingly, HPAEC-PAD is a more rapid and simple method than the traditional coupled assays given its high specificity and sensitivity, and will certainly bring convenience to further research of α-D-phosphohexomutases. PMID:26788420

  6. Reactor Monitoring with Neutrino Detectors

    The study of the use of neutrino detectors to monitor nuclear reactors is currently a very active field of research. While neutrino detectors located close to reactors have been used to provide information about the global performance of the reactors, a general improvement of the technique is needed in order to use it in a practical way to monitor the fissile contents of the fuel of the nuclear reactors or the thermal power delivered. I describe the current status of the Angra Neutrino Project, aimed to building a low-mass neutrino detector to monitor the Angra II reactor of the Brazilian nuclear power plant Almirante Alvaro Ramos in order to explore new approaches to reactor monitoring with neutrino detectors.

  7. Computational studies of BEGe detectors

    Salathe, Marco [Max Planck Institut fuer Kernphysik, Heidelberg (Germany)

    2013-07-01

    The GERDA experiment searches for the neutrinoless double beta decay within the active volume of germanium detectors. Simulations of the physical processes within such detectors are vital to gain a better understanding of the measurements. The simulation procedure follows three steps: First it calculates the electric potential, next it simulates the electron and hole drift within the germanium crystal and finally it generates a corresponding signal. The GERDA collaboration recently characterized newly produced Broad Energy Germanium Detectors (BEGe) in the HADES underground laboratory in Mol, Belgium. A new pulse shape simulation library was established to examine the results of these measurements. The library has also proven to be a very powerful tool for other applications such as detector optimisation studies. The pulse shape library is based on ADL 3.0 (B. Bruyneel, B. Birkenbach, http://www.ikp.uni-koeln.de/research/agata/download.php) and m3dcr (D. Radford, http://radware.phy.ornl.gov/MJ/m3dcr).

  8. Active induction balance method for metal detector sensing head utilizing transmitter-bucking and dual current source

    A central problem in a design of frequency domain electromagnetic induction sensors used in landmine detection is an effective suppression of a direct inductive coupling between the transmitter and the receiver coil (induction balance, IB). In sensing heads based on the transmitter-bucking configuration, IB is achieved by using two concentric transmitter coils with opposing exciter fields in order to create a central magnetic cavity for the receiver coil. This design has numerous advantages over other IB methods in terms of detection sensitivity, spatial resolution, sensor dimensions and suitability for model-based measurements. However, very careful design and precise sensing head geometry are required if a single excitation source is used for driving both transmitter coils. In this paper we analyze the IB sensitivity to small perturbations of geometrical properties of coils. We propose a sensor design with dual current source and active induction balance scheme which overcomes the limitations of geometry-based balancing and potentially provides more efficient compensation of soil effects.

  9. Study of variations of radon emanations from soil in Morocco using solid state nuclear track detectors. Correlations with atmospheric parameters and seismic activities

    This study investigates the quantity variations of radon emanating from soil in accordance with time. It aims to verify the possibility of the radon sign use in earthquake prediction. Regular measures of radon concentration in soil have been carried out over the two years 1991 and 1992 in five towns of Morocco: Rabat, Tetouan, Ifrane and Khouribga, and in geophysic observatory of Ibn Rochd (Berchid region). The measuring method is based on the solid state nuclear track detectors technique. The obtained results have shown an influence of the atmospheric effects on the radon emanation. The experiment proved that, on one hand, the variations of the aforesaid influence are correlated to variations of the pluviometry and the atmospheric temperature and, on the other hand, there is no notable effect of atmospheric pressure or atmospheric humidity. The good correlations between the different seismic activities and the variations of radon emanation rate in the five measurement stations, have shown the interest of radon use in the earthquake prediction field. 81 refs., 100 figs., 17 tabs.(F. M.)

  10. Search for neutrino events in the Kamiokande-II detector in correlation with the solar-flare activity in March 1989

    A search has been made for neutrino events (Ev > or approx. 50 MeV) in the Kamiokande-II water Cherenkov detector in correlation with the great solar-flare activity observed in March 1989. No evidence was obtained for such a correlation. Upper limits are separately given for the optical importance 4, 3, and 2 flares for both time-integrated and time-averaged solar-flare νe fluxes at Ev = 50 MeV and 100 MeV. At Ev = 100 MeV, the 90% confidence-level upper limit for the time-integrated νe flux per importance 4 (3) flare is 3.5 x 107 (1.4x107) cm-2. Even the upper limit for the importance 4 flare is considerably lower than the νe flux at the corresponding energy needed to explain the excess neutrino captures reported in some of the 37Cl experimental runs when large solar flares occurred. A search has also been made for low-energy events (recoil e+- energy > or approx. 10 MeV) in correlation with importance ≥ 2 flares and with the solar proton flux ≥ 10 MeV). Again, no significant signal has been observed. (author)