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Sample records for local acceleration due

  1. Damping in accelerators due to classical radiation

    International Nuclear Information System (INIS)

    Mills, F.E.

    1962-01-01

    The rates of change of the magnitudes of the adiabatic invariants is calculated in the case of a Hamiltonian system subjected to generalized non conservative forces. These results are applied to the case of the classical radiation of electrons in an accelerator or storage ring. The resulting expressions for the damping rates of three independent oscillation modes suggest structures which are damping in all three modes, while at the same time allowing 'strong focussing' and the attendant strong momentum compaction. (author)

  2. Limitations on plasma acceleration due to synchrotron losses

    International Nuclear Information System (INIS)

    Barletta, W.A.; Lee, E.P.; Bonifacio, R.; De Salvo, L.

    1999-01-01

    In this letter we consider the effect of synchrotron radiation losses due to the betatron motion of the electron beam in its self-induced magnetic field in a plasma accelerator taking into account the charge neutralization factor. The most favorable case is where the plasma density is smaller than the beam density. The contrary regime is strongly disfavored by the synchrotron radiation loss for beams with characteristics for TeV energies. In both cases we find that upon increasing the plasma density the synchrotron losses kill the acceleration process, so that there are limitations on the maximum allowable plasma density

  3. Occupational dose due to neutrons in medical linear accelerators

    International Nuclear Information System (INIS)

    Larcher, Ana M.; Bonet Duran, Stella M.; Lerner, Ana M.

    2000-01-01

    This paper describes a semi-empirical method to calculate the occupational dose due to neutrons and capture gamma rays in medical linear accelerators. It compares theoretical dose values with measurements performed in several 15 MeV medical accelerators installed in the country. Good agreement has been found between calculations made using the model and dose measurements, except for those accelerator rooms in which the maze length was shorter than the postulated tenth value distance. For those cases the model seems to overestimate neutron dose. The results demonstrate that the semi-empirical model is a good tool for quick and conservative shielding calculations for radiation protection purposes. Nevertheless, it is necessary to continue with the measurements in order to perform a more accurate validation of the model. (author)

  4. Occupational doses due to photoneutrons in medical linear accelerators rooms

    International Nuclear Information System (INIS)

    Soares, Alessandro Facure Neves de Salles

    2006-04-01

    Medical linear accelerators, with maximum photon energies above 10 MeV, are becoming of common use in Brazil. Although desirable in the therapeutic point of view, the increase in photon energies causes the generation of undesired neutrons, which are produced through nuclear reactions between photons and the high Z target nuclei of the materials that constitute the accelerator head. In this work, MCNP simulation was undertaken to examine the neutron equivalent doses around the accelerators head and at the entrance of medical linear accelerators treatment rooms, some of them licensed in Brazil by the National Regulatory Agency (CNEN). The simulated neutron dose equivalents varied between 2 e 26 μ Sv/Gy RX , and the results were compared with calculations performed with the use of some semi-empirical equations found in literature. It was found that the semi-empirical equations underestimate the simulated neutron doses in the majority of the cases, if compared to the simulated values, suggesting that these equations must be revised, due to the increasing number of high energy machines in the country. (author)

  5. Surfatron accelerator in the local interstellar cloud

    Energy Technology Data Exchange (ETDEWEB)

    Loznikov, V. M., E-mail: vloznikov@yandex.ru; Erokhin, N. S.; Zol’nikova, N. N.; Mikhailovskaya, L. A. [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2017-01-15

    Taking into account results of numerous experiments, the variability of the energy spectra of cosmic rays (protons and helium nuclei) in the energy range of 10 GeV to ~10{sup 7} GeV is explained on the basis of a hypothesis of the existence of two variable sources close to the Sun. The first (soft) surfatron source (with a size of ~100 AU) is located at the periphery of the heliosphere. The second (hard) surfatron source (with a size of ~1 pc) is situated in the Local Interstellar Cloud (LIC) at a distance of <1 pc. The constant background is described by a power-law spectrum with a slope of ~2.75. The variable heliospheric surfatron source is described by a power-law spectrum with a variable amplitude, slope, and cutoff energy, the maximum cutoff energy being in the range of E{sub CH}/Z < 1000 GeV. The variable surfatron source in the LIC is described by a power-law spectrum with a variable amplitude, slope, and cut-off energy, the maximum cut-off energy being E{sub Ð}¡{sub L}/Z ≤ 3 × 10{sup 6} GeV. The proposed model is used to approximate data from several experiments performed at close times. The energy of each cosmic-ray component is calculated. The possibility of surfatron acceleration of Fe nuclei (Z = 26) in the LIC up to an energy of E{sub CL} ~ 10{sup 17} eV and electron and positrons to the “knee” in the energy spectrum is predicted. By numerically solving a system of nonlinear equations describing the interaction between an electromagnetic wave and a charged particle with an energy of up to E/Z ~ 3 × 10{sup 6} GeV, the possibility of trapping, confinement, and acceleration of charged cosmic-ray particles by a quasi-longitudinal plasma wave is demonstrated.

  6. Application of local area networks to accelerator control systems at the Stanford Linear Accelerator

    International Nuclear Information System (INIS)

    Fox, J.D.; Linstadt, E.; Melen, R.

    1983-03-01

    The history and current status of SLAC's SDLC networks for distributed accelerator control systems are discussed. These local area networks have been used for instrumentation and control of the linear accelerator. Network topologies, protocols, physical links, and logical interconnections are discussed for specific applications in distributed data acquisition and control system, computer networks and accelerator operations

  7. Transverse emittance dilution due to coupler kicks in linear accelerators

    Directory of Open Access Journals (Sweden)

    Brandon Buckley

    2007-11-01

    Full Text Available One of the main concerns in the design of low emittance linear accelerators (linacs is the preservation of beam emittance. Here we discuss one possible source of emittance dilution, the coupler kick, due to transverse electromagnetic fields in the accelerating cavities of the linac caused by the power coupler geometry. In addition to emittance growth, the coupler kick also produces orbit distortions. It is common wisdom that emittance growth from coupler kicks can be strongly reduced by using two couplers per cavity mounted opposite each other or by having the couplers of successive cavities alternate from above to below the beam pipe so as to cancel each individual kick. While this is correct, including two couplers per cavity or alternating the coupler location requires large technical changes and increased cost for superconducting cryomodules where cryogenic pipes are arranged parallel to a string of several cavities. We therefore analyze consequences of alternate coupler placements. We show here that alternating the coupler location from above to below compensates the emittance growth as well as the orbit distortions. For sufficiently large Q values, alternating the coupler location from before to after the cavity leads to a cancellation of the orbit distortion but not of the emittance growth, whereas alternating the coupler location from before and above to behind and below the cavity cancels the emittance growth but not the orbit distortion. We show that cancellations hold for sufficiently large Q values. These compensations hold even when each cavity is individually detuned, e.g., by microphonics. Another effective method for reducing coupler kicks that is studied is the optimization of the phase of the coupler kick so as to minimize the effects on emittance from each coupler. This technique is independent of the coupler geometry but relies on operating on crest. A final technique studied is symmetrization of the cavity geometry in the

  8. Target spot localization at neutron producing accelerators

    International Nuclear Information System (INIS)

    Medveczki, L.; Bornemisza-Pauspertl, P.

    1980-01-01

    In the application of neutron producing accelerators it is required to know the actual position and the homogeneity of distribution of the emitted neutrons. Solid state nuclear track detectors offer a good possibility to get precise information on these without any disturbing influence on them. LR 115 2 type cellulose nitrate Kodak-Pathe Foils were irradiated with fast neutrons. When track density is higher than about 104 tracks cm -2 the damaged area can be observed with the naked eye, too. To get quantitative information the track densities were counted with manual technique. (author)

  9. Injury due to uncontrolled acceleration of an electric wheelchair.

    Science.gov (United States)

    Becker, D G; Washington, B V; Devlin, P M; Zook, J E; Edlich, R F

    1991-01-01

    Approximately 750,000 disabled individuals use electrical platform mobility aids (wheelchairs) for adaptive transportation. Because there are no mandatory standards for platform mobility aids and wheelchairs, these adaptive transportation aids are prone to potential design and maintenance problems. An injury caused by uncontrolled acceleration of a platform mobility aid is reported. Examination of the platform mobility aid identified a defect in its speed control regulator that has been subsequently corrected by the manufacturer.

  10. A mobile console for local access to accelerator control systems.

    CERN Multimedia

    1981-01-01

    Microprocessors were installed as auxiliary crate controllers (ACCs) in the CAMAC interface of control systems for various accelerators. The same ACC was also at the hearth of a stand-alone system in the form of a mobile console. This was also used for local access to the control systems for tests and development work (Annual Report 1981, p. 80, Fig. 10).

  11. Local re-acceleration and a modified thick target model of solar flare electrons

    Science.gov (United States)

    Brown, J. C.; Turkmani, R.; Kontar, E. P.; MacKinnon, A. L.; Vlahos, L.

    2009-12-01

    Context: The collisional thick target model (CTTM) of solar hard X-ray (HXR) bursts has become an almost “standard model” of flare impulsive phase energy transport and radiation. However, it faces various problems in the light of recent data, particularly the high electron beam density and anisotropy it involves. Aims: We consider how photon yield per electron can be increased, and hence fast electron beam intensity requirements reduced, by local re-acceleration of fast electrons throughout the HXR source itself, after injection. Methods: We show parametrically that, if net re-acceleration rates due to e.g. waves or local current sheet electric (E) fields are a significant fraction of collisional loss rates, electron lifetimes, and hence the net radiative HXR output per electron can be substantially increased over the CTTM values. In this local re-acceleration thick target model (LRTTM) fast electron number requirements and anisotropy are thus reduced. One specific possible scenario involving such re-acceleration is discussed, viz, a current sheet cascade (CSC) in a randomly stressed magnetic loop. Results: Combined MHD and test particle simulations show that local E fields in CSCs can efficiently accelerate electrons in the corona and and re-accelerate them after injection into the chromosphere. In this HXR source scenario, rapid synchronisation and variability of impulsive footpoint emissions can still occur since primary electron acceleration is in the high Alfvén speed corona with fast re-acceleration in chromospheric CSCs. It is also consistent with the energy-dependent time-of-flight delays in HXR features. Conclusions: Including electron re-acceleration in the HXR source allows an LRTTM modification of the CTTM in which beam density and anisotropy are much reduced, and alleviates theoretical problems with the CTTM, while making it more compatible with radio and interplanetary electron numbers. The LRTTM is, however, different in some respects such as

  12. Vacuum arc localization in CLIC prototype radio frequency accelerating structures

    CERN Document Server

    AUTHOR|(CDS)2091976; Koivunen, Visa

    2016-04-04

    A future linear collider capable of reaching TeV collision energies should support accelerating gradients beyond 100 MV/m. At such high fields, the occurrence of vacuum arcs have to be mitigated through conditioning, during which an accelerating structure’s resilience against breakdowns is slowly increased through repeated radio frequency pulsing. Conditioning is very time and resource consuming, which is why developing more efficient procedures is desirable. At CERN, conditioning related research is conducted at the CLIC high-power X-band test stands. Breakdown localization is an important diagnostic tool of accelerating structure tests. Abnormal position distributions highlight issues in structure design, manufacturing or operation and may consequently help improve these processes. Additionally, positioning can provide insight into the physics of vacuum arcs. In this work, two established positioning methods based on the time-difference-ofarrival of radio frequency waves are extended. The first method i...

  13. Local expansion flows of galaxies: quantifying acceleration effect of dark energy

    Science.gov (United States)

    Chernin, A. D.; Teerikorpi, P.

    2013-08-01

    The nearest expansion flow of galaxies observed around the Local group is studied as an archetypical example of the newly discovered local expansion flows around groups and clusters of galaxies in the nearby Universe. The flow is accelerating due to the antigravity produced by the universal dark energy background. We introduce a new acceleration measure of the flow which is the dimensionless ``acceleration parameter" Q (x) = x - x-2 depending on the normalized distance x only. The parameter is zero at the zero-gravity distance x = 1, and Q(x) ∝ x, when x ≫ 1. At the distance x = 3, the parameter Q = 2.9. Since the expansion flows have a self-similar structure in normalized variables, we expect that the result is valid as well for all the other expansion flows around groups and clusters of galaxies on the spatial scales from ˜ 1 to ˜ 10 Mpc everywhere in the Universe.

  14. Local effects in flow-accelerated corrosion wall thinning

    International Nuclear Information System (INIS)

    Pietralik, J.

    2006-01-01

    'Full text:' There is enough evidence that flow conditions play the dominant role locally in Flow-Accelerated Corrosion (FAC) under certain conditions, e.g., in CANDU feeders. While chemistry and materials set the overall potential for FAC, which can be low or high, flow conditions determine the local distribution of wall thinning. This relationship is not new and recent accurate measurements of FAC rate of a plant feeder bend confirm that the relationship between flow local conditions expressed by local mass transfer coefficient and FAC rate in CANDU feeder bends is close. There is also a lot of other direct and indirect, experimental and laboratory evidence about this relationship. This knowledge can be useful for minimizing inspection, predicting new locations for inspection, predicting the location with the highest FAC rate for a given piping component, e.g., feeder element, and determining what components or feeders and to what extent they should be replaced. It applies also to heat exchangers and steam generators. The objective of this paper is to examine the relationship between FAC rate and local flow parameters. For FAC, the most important flow parameter is mass transfer coefficient. The mass transfer coefficient describes the intensity of the transport of corrosion products from the oxide-water interface into the bulk water. Therefore, this parameter can be used for predicting the local distribution of FAC rate. It could also be used in planning experiments because time-varying surface roughness can explain the time-dependence of FAC rates. The paper presents plant and laboratory evidence about the relationship. In addition, it shows correlations for mass transfer coefficient in components that are highly susceptible to FAC. The role of surface roughness, wall shear stress, and local turbulence is also discussed. (author)

  15. Acute localized exanthem due to Coxsackievirus A4.

    Science.gov (United States)

    Drago, Francesco; Ciccarese, Giulia; Gariazzo, Lodovica; Cioni, Margherita; Parodi, Aurora

    2017-09-01

    Enteroviruses are the leading cause of exanthems in children, especially during summer and autumn. Enterovirus infections may occur in epidemics or small outbreaks. A 30-year-old woman presented with a three-day history of an erythematous maculopapular skin rash with petechiae localized exclusively under the nipple of the right breast. The skin eruption was associated with an erythematous-petechial enanthem. The patient complained of low-grade fever, headache, asthenia, sore throat and arthromyalgias. IgM (1:128) and IgG (1:640) antibodies against Coxsackievirus A4 were detected by the virus neutralization test. Reverse transcriptase real time polymerase chain reaction (PCR) assay detected enterovirus RNA in the patient's plasma and faeces. Diagnosis of an acute localized exanthem due to Coxsachievirus A4 was performed. Skin lesions improved in seven days and completely cleared in two weeks without any systemic or topical treatment. Physicians should be aware of the possibility that enteroviruses may determine localized skin eruptions in addition to hand-foot-mouth disease and atypical exanthems. Viral infections should be considered in the differential diagnosis of localized dermatitis especially when the skin eruption is associated with enanthems and with systemic symptoms.

  16. Accoustic Localization of Breakdown in Radio Frequency Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Peter Gwin [IIT, Chicago

    2016-07-01

    Current designs for muon accelerators require high-gradient radio frequency (RF) cavities to be placed in solenoidal magnetic fields. These fields help contain and efficiently reduce the phase space volume of source muons in order to create a usable muon beam for collider and neutrino experiments. In this context and in general, the use of RF cavities in strong magnetic fields has its challenges. It has been found that placing normal conducting RF cavities in strong magnetic fields reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields, it would be helpful to have a diagnostic tool which can localize the source of breakdown sparks inside the cavity. These sparks generate thermal shocks to small regions of the inner cavity wall that can be detected and localized using microphones attached to the outer cavity surface. Details on RF cavity sound sources as well as the hardware, software, and algorithms used to localize the source of sound emitted from breakdown thermal shocks are presented. In addition, results from simulations and experiments on three RF cavities, namely the Aluminum Mock Cavity, the High-Pressure Cavity, and the Modular Cavity, are also given. These results demonstrate the validity and effectiveness of the described technique for acoustic localization of breakdown.

  17. Accelerated Hyperfractionated Radiotherapy for Locally Advanced Uterine Cervix Cancers

    International Nuclear Information System (INIS)

    Seo, Young Seok; Cho, Chul Koo; Yoo, Seong Yul

    2008-01-01

    To assess the efficacy of the use of accelerated hyperfractionated radiotherapy (AHRT) for locally advanced uterine cervix cancers. Between May 2000 and September 2002, 179 patients were identified with FIGO stage IIB, IIIB, and IVA cancers. Of the 179 patients, 45 patients were treated with AHRT (AHRT group) and 134 patients were treated with conventional radiotherapy (CRT group), respectively. Patients undergoing the AHRT regimen received a dose of 30 Gy in 20 fractions (1.5 Gyx2 fractions/day) to the whole pelvis. Subsequently, with a midline block, we administered a parametrial boost with a dose of 20 Gy using 2 Gy fractions. Patients also received two courses of low-dose-rate brachytherapy, up to a total dose of 85∼90 Gy to point A. In the CRT group of patients, the total dose to point A was 85∼90 Gy. The overall treatment duration was a median of 37 and 66 days for patients that received AHRT and CRT, respectively. Statistical analysis was calculated by use of the Kaplan-Meier method, the log-rank test, and Chi-squared test. For patients that received cisplatin-based concurrent chemotherapy and radiotherapy, the local control rate at 5 years was 100% and 79.2% for the AHRT and CRT group of patients, respectively (p=0.028). The 5-year survival rate for patients with a stage IIB bulky tumor was 82.6% and 62.1% for the AHRT group and CRT group, respectively (p=0.040). There was no statistically significant difference for severe late toxicity between the two groups (p=0.561). In this study, we observed that treatment with AHRT with concurrent chemotherapy allows a significant advantage of local control and survival for locally advanced uterine cervix cancers

  18. Acquired Localized Cutis Laxa due to Increased Elastin Turnover

    DEFF Research Database (Denmark)

    Nygaard, Rie Harboe; Maynard, Scott; Schjerling, Peter

    2016-01-01

    Cutis laxa is a rare disease characterized by abnormal skin wrinkling and laxity, due to decreased elastin synthesis or structural extracellular matrix defects. We have explored elastin metabolism in a case of adult onset cutis laxa localized to the upper body of a woman. For this purpose, we...... obtained skin biopsies from affected and unaffected skin areas of the patient and analyzed these with microscopy, polymerase chain reaction, western blotting and cell culture experiments. Skin from the affected area lacked elastin fibers in electron microscopy but had higher mRNA expression of elastin...... and total RNA. Levels of an apparent tropoelastin degradation product were higher in the affected area. Fibroblast cultures from the affected area were able to produce elastin and showed higher proliferation and survival after oxidative and UVB stress compared to fibroblasts from the unaffected area...

  19. Quantified, localized health benefits of accelerated carbon dioxide emissions reductions

    Science.gov (United States)

    Shindell, Drew; Faluvegi, Greg; Seltzer, Karl; Shindell, Cary

    2018-04-01

    Societal risks increase as Earth warms, and increase further for emissions trajectories accepting relatively high levels of near-term emissions while assuming future negative emissions will compensate, even if they lead to identical warming as trajectories with reduced near-term emissions1. Accelerating carbon dioxide (CO2) emissions reductions, including as a substitute for negative emissions, hence reduces long-term risks but requires dramatic near-term societal transformations2. A major barrier to emissions reductions is the difficulty of reconciling immediate, localized costs with global, long-term benefits3,4. However, 2 °C trajectories not relying on negative emissions or 1.5 °C trajectories require elimination of most fossil-fuel-related emissions. This generally reduces co-emissions that cause ambient air pollution, resulting in near-term, localized health benefits. We therefore examine the human health benefits of increasing 21st-century CO2 reductions by 180 GtC, an amount that would shift a `standard' 2 °C scenario to 1.5 °C or could achieve 2 °C without negative emissions. The decreased air pollution leads to 153 ± 43 million fewer premature deaths worldwide, with 40% occurring during the next 40 years, and minimal climate disbenefits. More than a million premature deaths would be prevented in many metropolitan areas in Asia and Africa, and >200,000 in individual urban areas on every inhabited continent except Australia.

  20. Quantified, Localized Health Benefits of Accelerated Carbon Dioxide Emissions Reductions.

    Science.gov (United States)

    Shindell, Drew; Faluvegi, Greg; Seltzer, Karl; Shindell, Cary

    2018-01-01

    Societal risks increase as Earth warms, but also for emissions trajectories accepting relatively high levels of near-term emissions while assuming future negative emissions will compensate even if they lead to identical warming [1]. Accelerating carbon dioxide (CO 2 ) emissions reductions, including as a substitute for negative emissions, hence reduces long-term risks but requires dramatic near-term societal transformations [2]. A major barrier to emissions reductions is the difficulty of reconciling immediate, localized costs with global, long-term benefits [3, 4]. However, 2°C trajectories not relying on negative emissions or 1.5°C trajectories require elimination of most fossil fuel related emissions. This generally reduces co-emissions that cause ambient air pollution, resulting in near-term, localized health benefits. We therefore examine the human health benefits of increasing ambition of 21 st century CO 2 reductions by 180 GtC; an amount that would shift a 'standard' 2°C scenario to 1.5°C or could achieve 2°C without negative emissions. The decreased air pollution leads to 153±43 million fewer premature deaths worldwide, with ~40% occurring during the next 40 years, and minimal climate disbenefits. More than a million premature deaths would be prevented in many metropolitan areas in Asia and Africa, and >200,000 in individual urban areas on every inhabited continent except Australia.

  1. Qualitative models of magnetic field accelerated propagation in a plasma due to the Hall effect

    International Nuclear Information System (INIS)

    Kukushkin, A.B.; Cherepanov, K.V.

    2000-01-01

    Two qualitatively new models of accelerated magnetic field propagation (relative to normal diffusion) in a plasma due to the Hall effect are developed within the frames of the electron magnetic hydrodynamics. The first model is based on a simple hydrodynamic approach, which, in particular, reproduces the number of known theoretical results. The second one makes it possible to obtain exact analytical description of the basic characteristics of the magnetic field accelerated propagation in a inhomogeneous iso-thermic plasma, namely, the magnetic field front and its effective width [ru

  2. Local food: benefits and failings due to modern agriculture

    Directory of Open Access Journals (Sweden)

    Fábio Cunha Coelho

    Full Text Available ABSTRACT: This paper aims to examine the issue raised by the consumption of locally produced food in all its various aspects, and in particular, addresses how this practice contributes to local and global sustainability. It analyzes the different definitions of local food, the strategies used, the implications of the distance traveled in the transportation of food to the consumer's table – food miles, the relationships between local food consumption and sustainability, farming practices that reduce carbon emissions, contribution of urban agriculture to local food, local trading of food produced by rural farmers, as well as a number of relationships between the consumption of local food and human nutrition and health, local food protection and the ability to support local food production for humanitarian actions in disaster situations. The promotion of “local food” is a complex problem covering environmental issues, the economy and health. Transportation is not the only factor that determines how efficient it is to consume local food. Often, the technologies used for agricultural production are those most responsible for the degree of sustainability in the production and supply of food to the population. Local production does not always mean lower emissions of greenhouse gases. In general, the consumption of local foods, produced in ways adapted to the local environment using technologies with an ecological basis, is something beneficial and salutary for the environment, economy and society in general.

  3. Remanent radiation fields around medical linear accelerators due to the induced radionuclides

    International Nuclear Information System (INIS)

    Sabol, J.; Khalifa, O.; Berka, Z.; Stankus, P.; Frencl, L.

    1998-01-01

    Radiation fields around two linear accelerators, Saturn 43 and a Saturn 2 Plus, installed at radiotherapy department is Prague, were measured and interpreted. The measurements included the determination of the dose equivalent rate resulting from photons emitted by induced radionuclides produced in reactions of high-energy photons with certain elements present in air and accelerator components as well as in the shielding and building materials in the treatment rooms, which are irradiated by high-energy X-rays, and due to radionuclides formed by capture of photoneutrons. While scattered photons and photoneutrons are only present during the accelerator operation, residual radioactivity creates a remanent radiation field persisting for some time after the instrument shutdown. The activity induced in the accessories is also an important source of exposure. (P.A.)

  4. Improved scaling of temperature-accelerated dynamics using localization

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Yunsic; Amar, Jacques G. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States)

    2016-07-07

    While temperature-accelerated dynamics (TAD) is a powerful method for carrying out non-equilibrium simulations of systems over extended time scales, the computational cost of serial TAD increases approximately as N{sup 3} where N is the number of atoms. In addition, although a parallel TAD method based on domain decomposition [Y. Shim et al., Phys. Rev. B 76, 205439 (2007)] has been shown to provide significantly improved scaling, the dynamics in such an approach is only approximate while the size of activated events is limited by the spatial decomposition size. Accordingly, it is of interest to develop methods to improve the scaling of serial TAD. As a first step in understanding the factors which determine the scaling behavior, we first present results for the overall scaling of serial TAD and its components, which were obtained from simulations of Ag/Ag(100) growth and Ag/Ag(100) annealing, and compare with theoretical predictions. We then discuss two methods based on localization which may be used to address two of the primary “bottlenecks” to the scaling of serial TAD with system size. By implementing both of these methods, we find that for intermediate system-sizes, the scaling is improved by almost a factor of N{sup 1/2}. Some additional possible methods to improve the scaling of TAD are also discussed.

  5. Improved scaling of temperature-accelerated dynamics using localization

    International Nuclear Information System (INIS)

    Shim, Yunsic; Amar, Jacques G.

    2016-01-01

    While temperature-accelerated dynamics (TAD) is a powerful method for carrying out non-equilibrium simulations of systems over extended time scales, the computational cost of serial TAD increases approximately as N 3 where N is the number of atoms. In addition, although a parallel TAD method based on domain decomposition [Y. Shim et al., Phys. Rev. B 76, 205439 (2007)] has been shown to provide significantly improved scaling, the dynamics in such an approach is only approximate while the size of activated events is limited by the spatial decomposition size. Accordingly, it is of interest to develop methods to improve the scaling of serial TAD. As a first step in understanding the factors which determine the scaling behavior, we first present results for the overall scaling of serial TAD and its components, which were obtained from simulations of Ag/Ag(100) growth and Ag/Ag(100) annealing, and compare with theoretical predictions. We then discuss two methods based on localization which may be used to address two of the primary “bottlenecks” to the scaling of serial TAD with system size. By implementing both of these methods, we find that for intermediate system-sizes, the scaling is improved by almost a factor of N 1/2 . Some additional possible methods to improve the scaling of TAD are also discussed.

  6. Accelerating Net Terrestrial Carbon Uptake During the Warming Hiatus Due to Reduced Respiration

    Science.gov (United States)

    Ballantyne, Ashley; Smith, William; Anderegg, William; Kauppi, Pekka; Sarmiento, Jorge; Tans, Pieter; Shevliakova, Elena; Pan, Yude; Poulter, Benjamin; Anav, Alessandro; hide

    2017-01-01

    The recent warming hiatus presents an excellent opportunity to investigate climate sensitivity of carbon cycle processes. Here we combine satellite and atmospheric observations to show that the rate of net biome productivity (NBP) has significantly accelerated from - 0.007 +/- 0.065 PgC yr(exp -2) over the warming period (1982 to 1998) to 0.119 +/- 0.071 PgC yr(exp -2) over the warming hiatus (19982012). This acceleration in NBP is not due to increased primary productivity, but rather reduced respiration that is correlated (r = 0.58; P = 0.0007) and sensitive ( y = 4.05 to 9.40 PgC yr(exp -1) per C) to land temperatures. Global land models do not fully capture this apparent reduced respiration over the warming hiatus; however, an empirical model including soil temperature and moisture observations better captures the reduced respiration.

  7. Hydromagnetic perturbations due to localized flows: An eddy theorem

    International Nuclear Information System (INIS)

    Bird, J.F.

    1979-01-01

    The hydromagnetic far-field generated by localized regions of incompressible flow of electrically conducting media in uniform magnetic fields is derived explicitly in terms of the spin angular momentum of the flow. Some applications and a corollary result for bounded media are given

  8. Local control of T3 carcinomas after accelerated fractionation: a look at the 'gap'

    International Nuclear Information System (INIS)

    Wang, C.C.; Efird, Jimmy; Nakfoor, Bruce; Martins, Patricia

    1996-01-01

    Purpose: To study the effects of midcourse treatment break or gaps related to the local control of T3 carcinoma of the oropharynx and larynx following accelerated hyperfractionated radiation therapy. Methods and Materials: All patients were treated at the Massachusetts General Hospital from 1979 through 1994 with treatment consisting of 1.6 Gy per fraction, two fractions a day for the treatment of T3 carcinoma of the oropharynx and larynx. They were entered in the head and neck data base. Their treatment dates, treatment breaks, and doses vs. local control were analyzed and compared. A p-value of 0.05 was considered statistically significant. Results: A total of 162 patients were available for review. Due to the acute severe mucosal effects, most of the patients required a midcourse pause or 'break' after a dose of 38.4-48 Gy before treatment could be resumed and completed. The data indicate that (a) prolongation of the treatment gap for more than 14 days, (b) total treatment course longer than 45 days, (c) total dose less than 67 Gy, and (d) male gender adversely affected local control. In spite of the gaps, the female patients with advanced carcinomas enjoyed the benefits of improved local control after the accelerated hyperfractionated radiation therapy. Conclusions: Accelerated hyperfractionation radiation therapy using 1.6 Gy per fraction/twice-a-day (b.i.d.) for a total dose of 70.4 Gy in 6 weeks is effective in achieving high local control of T3 squamous cell carcinoma of the oropharynx and larynx. The midcourse treatment gap should be as short as possible with the projected total dose and time. Should the gaps be unduly prolonged due to various circumstances, further increase in the total dose, for example, 72-75 Gy, and/or increase of the fraction sizes, for example, 1.8-2.0 Gy/f b.i.d. after the gap may be necessary to compensate for the adverse effects of the tumor regeneration from the prolonged gap

  9. Dose levels due to neutrons in the vicinity of high energy medical accelerators

    International Nuclear Information System (INIS)

    McGinley, P.H.; Wood, M.; Sohrabi, M.; Mills, M.; Rodriguez, R.

    1976-01-01

    High energy photons are generated for use in radiation therapy by the decelleration of electrons in metal targets. Fast neutrons are also generated as a result of (γ, n) and (e, e'n) interactions in the target, beam compensator filter, and collimator material. In this work the adsorbed dose to neutrons was measured at the center of a 10 x 10 cm photon beam and 5 cm outside of the beam edge for a number of treatment units. Dose levels due to slow and fast neutrons were also established outside of the treatment rooms and a Bonner sphere neutron spectrometer system was employed to determine the neutron energy spectrum due to stray neutron radiation at each accelerator. For the linac it was found that the neutron dose at the beam center was 0.0039% of the photon dose and values of 0.049% and 0.053% were observed for the Allis Chalmers betatron and the Brown Boveri Betatron. Dose equivalent rates in the range of 0.3 to 22.5 mrem/hr were measured for points outside the treatment rooms when the accelerators were operated at a photon dose rate of 100 rad/min at the treatment position

  10. Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

    International Nuclear Information System (INIS)

    Bane, K

    2008-01-01

    In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm

  11. Acute skin lesions due to localized ''hot particle'' radiation exposures

    International Nuclear Information System (INIS)

    Baum, J.W.; Carsten, A.L.; Kaurin, D.G.L.; Schaefer, C.W.

    1996-01-01

    Purpose of the studies was to determine incidence and severity of lesions resulting from localized deposition of dose to the skin from small ( 2 at 70μm depth) from isotopes having max beta particle energies from about 0.3-3 MeV. Incidence of erythema and scabs (indicating ulceration) were scored routinely for up to 71 days post-irradiation. Responses followed normal probability distributions, and thus, no true threshold could be defined. Ten and 50% incidence rates were deduced using probit analyses. Lowest dose producing 10% incidence was about 1 Gy for exposures to Yb-175 (0.5 MeV max energy) beta particles. Severity of lesions was estimated using diameters and persistence. From preliminary considerations of probability of induction, size, and persistence of acute lesions, a special limit for hot particle exposures in the range of 5-50 Gy may be reasonable, with an action level between about 1 Gy and the limit

  12. Random Taylor hypothesis and the behavior of local and convective accelerations in isotropic turbulence

    NARCIS (Netherlands)

    Tsinober, A.; Vedula, P.; Yeung, P.K.

    2001-01-01

    The properties of acceleration fluctuations in isotropic turbulence are studied in direct numerical simulations (DNS) by decomposing the acceleration as the sum of local and convective contributions (aL = ?u/?t and aC = u??u), or alternatively as the sum of irrotational and solenoidal contributions

  13. Improved techniques of impedance calculation and localization in particle accelerators

    CERN Document Server

    Biancacci, Nicolò; Migliorati, Mauro; Métral, Elias; Salvant, Benoit

    In this thesis we mainly focus on particle accelerators applied to high energy physics research where a fundamental parameter, the luminosity, is maximized in order to increase the rate of particle collisions useful to particle physicists. One way to increase this parameter is to increase the intensity of the circulating beams which is limited by the onset of collective effects that may drive the beam unstable and eventually provoke beam losses or reduce the beam quality required by the particle physics experiments. One major cause of collective effects is the beam coupling impedance, a quantity that quantifies the effect of the fields scattered by a beam passing through any accelerator device. The development of an impedance budget is required in those machines that are planning substantial upgrades as shown in this thesis for the CERN PS case. The main source of impedance in the CERN LHC are the collimators. Within an impedance reduction perspective, in order to reach the goals of the planned upgrades, it ...

  14. Longitudinal beam instability due to the ring impedance at KEK's accelerator test facility damping ring

    International Nuclear Information System (INIS)

    Kim, Eun-San

    2003-01-01

    This paper shows the results of a numerical study of the impedance in the Accelerator Test Facility damping ring. The longitudinal impedance in the damping ring is shown to be inductive. It is shown that the total impedance |Z || /n| is 0.23 Ω and the inductance is L = 14 nH. In the extremely low emittance beam of the damping ring, bunch lengthening is caused by both the effects of potential-well distortion and intra-beam scattering. In this paper, the bunch-lengthening due to the ring impedance is numerically investigated, and the result shows qualitative agreement with the result of an analysis performed using the bunch-length measurement. With the calculated longitudinal impedance, the instability threshold in the damping ring is estimated to be a bunch population of 3.3 x 10 10 by using both a Vlasov equation approach and a multi-particle tracking method.

  15. Is cosmic acceleration proven by local cosmological probes?

    Science.gov (United States)

    Tutusaus, I.; Lamine, B.; Dupays, A.; Blanchard, A.

    2017-06-01

    Context. The cosmological concordance model (ΛCDM) matches the cosmological observations exceedingly well. This model has become the standard cosmological model with the evidence for an accelerated expansion provided by the type Ia supernovae (SNIa) Hubble diagram. However, the robustness of this evidence has been addressed recently with somewhat diverging conclusions. Aims: The purpose of this paper is to assess the robustness of the conclusion that the Universe is indeed accelerating if we rely only on low-redshift (z ≲ 2) observations, that is to say with SNIa, baryonic acoustic oscillations, measurements of the Hubble parameter at different redshifts, and measurements of the growth of matter perturbations. Methods: We used the standard statistical procedure of minimizing the χ2 function for the different probes to quantify the goodness of fit of a model for both ΛCDM and a simple nonaccelerated low-redshift power law model. In this analysis, we do not assume that supernovae intrinsic luminosity is independent of the redshift, which has been a fundamental assumption in most previous studies that cannot be tested. Results: We have found that, when SNIa intrinsic luminosity is not assumed to be redshift independent, a nonaccelerated low-redshift power law model is able to fit the low-redshift background data as well as, or even slightly better, than ΛCDM. When measurements of the growth of structures are added, a nonaccelerated low-redshift power law model still provides an excellent fit to the data for all the luminosity evolution models considered. Conclusions: Without the standard assumption that supernovae intrinsic luminosity is independent of the redshift, low-redshift probes are consistent with a nonaccelerated universe.

  16. Parallelized Local Volatility Estimation Using GP-GPU Hardware Acceleration

    KAUST Repository

    Douglas, Craig C.; Lee, Hyoseop; Sheen, Dongwoo

    2010-01-01

    We introduce an inverse problem for the local volatility model in option pricing. We solve the problem using the Levenberg-Marquardt algorithm and use the notion of the Fréchet derivative when calculating the Jacobian matrix. We analyze

  17. Parallelized Local Volatility Estimation Using GP-GPU Hardware Acceleration

    KAUST Repository

    Douglas, Craig C.

    2010-01-01

    We introduce an inverse problem for the local volatility model in option pricing. We solve the problem using the Levenberg-Marquardt algorithm and use the notion of the Fréchet derivative when calculating the Jacobian matrix. We analyze the existence of the Fréchet derivative and its numerical computation. To reduce the computational time of the inverse problem, a GP-GPU environment is considered for parallel computation. Numerical results confirm the validity and efficiency of the proposed method. ©2010 IEEE.

  18. Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model

    International Nuclear Information System (INIS)

    Cox, P.M.; Betts, R.A.; Jones, C.D.; Spall, S.A.; Totterdell, I.J.

    2000-01-01

    The continued increase in the atmospheric concentration of carbon dioxide due to anthropogenic emissions is predicted to lead to significant changes in climate. About half of the current emissions are being absorbed by the ocean and by land ecosystems, but this absorption is sensitive to climate as well as to atmospheric carbon dioxide concentrations, creating a feedback loop. General circulation models have generally excluded the feedback between climate and the biosphere, using static vegetation distributions and CO 2 concentrations from simple carbon-cycle models that do not include climate change. Here we present results from a fully coupled, three-dimensional carbon-climate model, indicating that carbon-cycle feedbacks could significantly accelerate climate change over the twenty-first century. We find that under a 'business as usual' scenario, the terrestrial biosphere acts as an overall carbon sink until about 2050, but turns into a source thereafter. By 2100, the ocean uptake rate of 5 Gt C yr -1 is balanced by the terrestrial carbon source, and atmospheric CO 2 concentrations are 250 p.p.m.v. higher in our fully coupled simulation than in uncoupled carbon models, resulting in a global-mean warming of 5.5 K, as compared to 4 K without the carbon-cycle feedback. (author)

  19. Phase-space holes due to electron and ion beams accelerated by a current-driven potential ramp

    Directory of Open Access Journals (Sweden)

    M. V. Goldman

    2003-01-01

    Full Text Available One-dimensional open-boundary simulations have been carried out in a current-carrying plasma seeded with a neutral density depression and with no initial electric field. These simulations show the development of a variety of nonlinear localized electric field structures: double layers (unipolar localized fields, fast electron phase-space holes (bipolar fields moving in the direction of electrons accelerated by the double layer and trains of slow alternating electron and ion phase-space holes (wave-like fields moving in the direction of ions accelerated by the double layer. The principal new result in this paper is to show by means of a linear stability analysis that the slow-moving trains of electron and ion holes are likely to be the result of saturation via trapping of a kinetic-Buneman instability driven by the interaction of accelerated ions with unaccelerated electrons.

  20. Localized Beampipe Heating due to $e^{-}$ Capture and Nuclear Excitation in Heavy Ion Colliders

    CERN Document Server

    Klein, S R

    2001-01-01

    At heavy ion colliders, two major sources of beam loss are expected to be $e^+e^-$ production, where the $e^-$ is bound to one of the nuclei, and photonuclear excitation and decay via neutron emission. Both processes alter the ions charged to mass ratio by well defined amounts, creating beams of particles with altered magnetic rigidity. These beams will deposit their energy in a localized region of the accelerator, causing localized heating, The size of the target region depends on the collider optics. For medium and heavy ions, at design luminosity at the Large Hadron Collider, local heating may be more than an order of magnitude higher than expected. This could cause magnet quenches if the local cooling is inadequate. The altered-rigidity beams will also produce localized radiation damage. The beams could also be extracted and used for fixed target experiments.

  1. Very accelerated radiation therapy: preliminary results in locally unresectable head and neck carcinomas

    Energy Technology Data Exchange (ETDEWEB)

    Bourhis, Jean; Fortin, Andre; Dupuis, Olivier; Domenge, Christian; Lusinchi, Antoine; Marandas, Patrick; Schwaab, Guy; Armand, Jean Pierre; Luboinski, Bernard; Malaise, Edmond; Eschwege, Francois; Wibault, Pierre

    1995-06-15

    Purpose: To report preliminary results of a very accelerated radiation therapy Phase I/II trial in locally advanced head and squamous cell carcinomas (HNSCC). Methods and Materials: Between 01/92 and 06/93, 35 patients with an unresectable HNSCC were entered in this study. Thirty-two (91%) had Stage IV, and 3 had Stage III disease. The mean nodal diameter, in patients with clinically involved nodes (83%), was 6.3 cm. The median Karnovsky performance status was 70. The treatment consisted of a twice daily schedule (BID) giving 62 Gy in 20 days. Results: In all cases, confluent mucositis was observed, which started about day 15 and resolved within 6 to 10 weeks. Eighty percent of patients had enteral nutritional support. The nasogastric tube or gastrostomy was maintained in these patients for a mean duration of 51.8 days. Eighteen patients (53%) were hospitalized during the course of treatment due to a poor medical status or because they lived far from the center (mean 25 days). Nineteen patients (56%) (some of whom were initially in-patients) were hospitalized posttreatment for toxicity (mean 13 days). Five patients (15%) were never hospitalized. During the follow-up period, 12 local and/or regional failures were observed. The actuarial 18-month loco-regional control rate was 59% (95% confidence interval, 45-73%). Conclusions: The dramatic shortening of radiation therapy compared to conventional schedules in our series of very advanced HNSCC resulted in: (a) severe acute mucosal toxicity, which was manageable but required intensive nutritional support in all cases; and (b) high loco-regional response rates, strongly suggesting that the time factor is likely to be critical for tumor control in this type of cancer.

  2. Continuous hyperfractionated accelerated radiotherapy (chart) in localized cancer of the esophagus

    International Nuclear Information System (INIS)

    Powell, Melanie E.B.; Hoskin, Peter J.; Saunders, Michele I.; Foy, Christopher J.W.; Dische, Stanley

    1997-01-01

    Purpose: To assess the efficacy and toxicity of continuous hyperfractionated accelerated radiotherapy (CHART) in locoregional control compared with a historical group of patients treated with conventionally fractionated radical radiotherapy. Methods and Materials: Between 1985 and 1994, 54 patients with localized esophageal cancer were treated with CHART. Twenty-eight patients received CHART alone (54 Gy in 36 fractions over 12 consecutive days) and 15 were given intravenous mitomycin C and cisplatin on days 10 and 13, respectively. Eleven patients received 40.5 Gy in 27 fractions over 9 days, followed by a single high-dose-rate intraluminal brachytherapy insertion of 15 Gy at 1 cm. Results: Acute toxicity was well tolerated and dysphagia was improved in 35 patients (65%), with 28 (52%) eating a normal diet by week 12. This compares with an improvement in dysphagia score in 72% of the conventionally treated group. The median duration of relief of dysphagia was 7.8 months (range 0-41.4) in the CHART group compared with 5.5 months (range 0-48) in the controls. Strictures developed in 29 patients (61%) and 18 were confirmed on biopsy to be due to recurrent disease. Median survival was 12 months (range 0.5-112) in the CHART group and 15 months (range 3.6-56) in the control patients. Conclusion: CHART is well tolerated and achieves a high rate of local control. Palliation in the short overall treatment time of esophageal cancer is an advantage in these patients whose median survival is only 12 months

  3. Structural activation calculations due to proton beam loss in the APT accelerator design

    International Nuclear Information System (INIS)

    Lee, S. K.; Beard, C. A.; Wilson, W. B.; Daemen, L. L.; Liska, D. J.; Waters, L. S.; Adams, M. L.

    1995-01-01

    For the new, high-power accelerators currently being designed, the amount of activation of the accelerator structure has become an important issue. To quantify this activation, a methodology was utilized that coupled transport and depletion codes to obtain dose rate estimates at several locations near the accelerator. This research focused on the 20 and 100 MeV sections of the Bridge-Coupled Drift Tube Linear Accelerator. The peak dose rate was found to be approximately 6 mR/hr in the 100 MeV section near the quadrupoles at a 25-cm radius for an assumed beam loss of 1 nA/m. It was determined that the activation was dominated by the proton interactions and subsequent spallation product generation, as opposed to the presence of the generated neutrons. The worst contributors were the spallation products created by proton bombardment of iron, and the worst component was the beam pipe, which consists mostly of iron. No definitive conclusions about the feasibility of hands-on maintenance can be determined, as the design is still not finalized

  4. Structural activation calculations due to proton beam loss in the APT accelerator design

    International Nuclear Information System (INIS)

    Lee, S.K.; Beard, C.A.; Wilson, W.B.; Daemen, L.L.; Liska, D.J.; Waters, L.S.; Adams, M.L.

    1994-01-01

    For the new, high-power accelerators currently being designed, the amount of activation of the accelerator structure has become an important issue. To quantify this activation, a methodology was utilized that coupled transport and depletion codes to obtain dose rate estimates at several locations near the accelerator. This research focused on the 20 and 100 MeV sections of the Bridge-Coupled Drift Tube Linear Accelerator. The peak dose rate was found to be approximately 6 mR/hr in the 100 MeV section near the quadrupoles at a 25-cm radius for an assumed beam loss of 1 nA/m. It was determined that the activation was dominated by the proton interactions and subsequent spallation product generation, as opposed to the presence of the generated neutrons. The worst contributors were the spallation products created by proton bombardment of iron, and the worst component was the beam pipe, which consists mostly of iron. No definitive conclusions about the feasibility of hands-on maintenance can be determined, as the design is still not finalized

  5. Ion acceleration in a helicon source due to the self-bias effect

    Energy Technology Data Exchange (ETDEWEB)

    Wiebold, Matt; Sung, Yung-Ta; Scharer, John E. [University of Wisconsin-Madison, Electrical and Computer Engineering, Madison, Wisconsin 53706 (United States)

    2012-05-15

    Time-averaged plasma potential differences up to 165 V over several hundred Debye lengths are observed in low pressure (p{sub n} < 1 mTorr) expanding argon plasmas in the Madison Helicon eXperiment (MadHeX). The potential gradient leads to ion acceleration greater than that predicted by ambipolar expansion, exceeding E{sub i} Almost-Equal-To 7 kT{sub e} in some cases. RF power up to 500 W at 13.56 MHz is supplied to a half-turn, double-helix antenna in the presence of a nozzle magnetic field, adjustable up to 1 kG. A retarding potential analyzer (RPA) measures the ion energy distribution function (IEDF) and a swept emissive probe measures the plasma potential. Single and double probes measure the electron density and temperature. Two distinct mode hops, the capacitive-inductive (E-H) and inductive-helicon (H-W) transitions, are identified by jumps in density as RF power is increased. In the capacitive (E) mode, large fluctuations of the plasma potential (V{sub p-p} Greater-Than-Or-Equivalent-To 140V, V{sub p-p}/V{sub p} Almost-Equal-To 150%) exist at the RF frequency and its harmonics. The more mobile electrons can easily respond to RF-timescale gradients in the plasma potential whereas the inertially constrained ions cannot, leading to an initial flux imbalance and formation of a self-bias voltage between the source and expansion chambers. In the capacitive mode, the ion acceleration is not well described by an ambipolar relation, while in the inductive and helicon modes the ion acceleration more closely follows an ambipolar relation. The scaling of the potential gradient with the argon flow rate and RF power are investigated, with the largest potential gradients observed for the lowest flow rates in the capacitive mode. The magnitude of the self-bias voltage agrees with that predicted for RF self-bias at a wall. Rapid fluctuations in the plasma potential result in a time-dependent axial electron flux that acts to 'neutralize' the accelerated ion

  6. Accelerators

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    The talk summarizes the principles of particle acceleration and addresses problems related to storage rings like LEP and LHC. Special emphasis will be given to orbit stability, long term stability of the particle motion, collective effects and synchrotron radiation.

  7. A fiber optic strain measurement and quench localization for use in superconducting accelerator dipole magnets

    International Nuclear Information System (INIS)

    van Oort, J.M.; Scanlan, R.M.; ten Kate, H.H.J.

    1994-01-01

    A novel fiber-optic measurement system for superconducting accelerator magnets is described. The principal component is an extrinsic Fabry-Perot Interferometer to determine localized strain and stress in coil windings. The system can be used either as a sensitive relative strain measurement system or as an absolute strain detector. Combined, one can monitor the mechanical behaviour of the magnet system over time during construction, long time storage and operation. The sensing mechanism is described, together with various tests in laboratory environments. The test results of a multichannel test matrix to be incorporated first in the dummy coils and then in the final version of a 13T Nb 3 Sn accelerator dipole magnet are presented. Finally, the possible use of this system as a quench localization system is proposed

  8. Flame acceleration due to wall friction: Accuracy and intrinsic limitations of the formulations

    Science.gov (United States)

    Demirgok, Berk; Sezer, Hayri; Akkerman, V.'Yacheslav

    2015-11-01

    The analytical formulations on the premixed flame acceleration induced by wall friction in two-dimensional (2D) channels [Bychkov et al., Phys. Rev. E 72 (2005) 046307] and cylindrical tubes [Akkerman et al., Combust. Flame 145 (2006) 206] are revisited. Specifically, pipes with one end closed are considered, with a flame front propagating from the closed pipe end to the open one. The original studies provide the analytical formulas for the basic flame and fluid characteristics such as the flame acceleration rate, the flame shape and its propagation speed, as well as the flame-generated flow velocity profile. In the present work, the accuracy of these approaches is verified, computationally, and the intrinsic limitations and validity domains of the formulations are identified. Specifically, the error diagrams are presented to demonstrate how the accuracy of the formulations depends on the thermal expansion in the combustion process and the Reynolds number associated with the flame propagation. It is shown that the 2D theory is accurate enough for a wide range of parameters. In contrast, the zeroth-order approximation for the cylindrical configuration appeared to be quite inaccurate and had to be revisited. It is subsequently demonstrated that the first-order approximation for the cylindrical geometry is very accurate for realistically large thermal expansions and Reynolds numbers. Consequently, unlike the zeroth-order approach, the first-order formulation can constitute a backbone for the comprehensive theory of the flame acceleration and detonation initiation in cylindrical tubes. Cumulatively, the accuracy of the formulations deteriorates with the reduction of the Reynolds number and thermal expansion.

  9. Accelerated Recombination in Cold Dense Plasmas with Metastable Ions due to Resonant Deexcitation

    International Nuclear Information System (INIS)

    Ralchenko, Yu.V.; Maron, M.

    2001-01-01

    In a recombining plasma the metastable states are known to accumulate population thereby slowing down the recombination process. We show that a proper account of the doubly-excited autoionizing states, populated through collisional 3-body recombination of metastable ions, results in a significant acceleration of recombination. 3-body recombination followed by collisional (de)excitations and autoionization effectively produces deexcitation via the following chain of elementary events: A fully time-dependent collisional-radiative (CR) modeling for stripped ions of carbon recombining in a cold dense plasma demonstrates an order of magnitude faster recombination of He-like ions. The CR model used in calculations is discussed in details

  10. Obtaining the Wakefield Due to Cell-to-Cell Misalignments in a Linear Accelerator Structure

    OpenAIRE

    Bane, Karl L. F.; Li, Zenghai

    2001-01-01

    A linear accelerator structure, such as will be used in the linacs of the JLC/NLC collider, is composed of on the order of 100 cells. The cells are constructed as individual cups that are brazed together to form a structure. Fabrication error will result in slight cell-to-cell misalignments along the finished structure. In this report we derive an approximation to the transverse wakefield of a structure with cell-to-cell misalignments in terms of the eigenfunctions and eigenvalues of the erro...

  11. Spatial dependence and origin of the ambient doce due to neutron activation processes in linear accelerators

    International Nuclear Information System (INIS)

    Ruiz Egea, E.; Sanchez Carrascal, M.; Torres Pozas, S.; Monja Ray, P. de la; Perez Molina, J. L.; Madan Rodriguez, C.; Luque Japon, L.; Morera Molina, A.; Hernandez Perez, A.; Barquero Bravo, Y.; Morengo Pedagna, I.; Oliva Gordillo, M. C.; Martin Olivar, R.

    2011-01-01

    In order to try to determine the high dose in the bunker of a Linear Accelerator clinical use trying to measure the spatial dependence of the sane f ron the isocenter to tite gateway to the Board ceeking to establich the origin of it. This doce measurements performed with an ionization charober at different locations incide the bunker after an irradiation of 400 Monitor Units verifying the doce rate per minute for an hour, and accumulating the doce received during that period of time.

  12. Ion acceleration in a helicon source due to the self-bias effect

    International Nuclear Information System (INIS)

    Wiebold, Matt; Sung, Yung-Ta; Scharer, John E.

    2012-01-01

    Time-averaged plasma potential differences up to 165 V over several hundred Debye lengths are observed in low pressure (p n i ≈ 7 kT e in some cases. RF power up to 500 W at 13.56 MHz is supplied to a half-turn, double-helix antenna in the presence of a nozzle magnetic field, adjustable up to 1 kG. A retarding potential analyzer (RPA) measures the ion energy distribution function (IEDF) and a swept emissive probe measures the plasma potential. Single and double probes measure the electron density and temperature. Two distinct mode hops, the capacitive-inductive (E-H) and inductive-helicon (H-W) transitions, are identified by jumps in density as RF power is increased. In the capacitive (E) mode, large fluctuations of the plasma potential (V p-p ≳140V, V p-p /V p ≈150%) exist at the RF frequency and its harmonics. The more mobile electrons can easily respond to RF-timescale gradients in the plasma potential whereas the inertially constrained ions cannot, leading to an initial flux imbalance and formation of a self-bias voltage between the source and expansion chambers. In the capacitive mode, the ion acceleration is not well described by an ambipolar relation, while in the inductive and helicon modes the ion acceleration more closely follows an ambipolar relation. The scaling of the potential gradient with the argon flow rate and RF power are investigated, with the largest potential gradients observed for the lowest flow rates in the capacitive mode. The magnitude of the self-bias voltage agrees with that predicted for RF self-bias at a wall. Rapid fluctuations in the plasma potential result in a time-dependent axial electron flux that acts to “neutralize” the accelerated ion population, resulting in a zero net time-averaged current through the acceleration region when an insulating upstream boundary condition is enforced. Grounding the upstream endplate increases the self-bias voltage compared to a floating endplate.

  13. Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

    Science.gov (United States)

    Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

    2014-11-28

    Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet. Copyright © 2014, American Association for the Advancement of Science.

  14. Accelerated forgetting of contextual details due to focal medio-dorsal thalamic lesion

    Directory of Open Access Journals (Sweden)

    Sicong eTu

    2014-09-01

    Full Text Available Effects of thalamic nuclei damage and related white matter tracts on memory performance are still debated. This is particularly evident for the medio-dorsal thalamus which has been less clear in predicting amnesia than anterior thalamus changes. The current study addresses this issue by assessing 7 thalamic stroke patients with consistent unilateral lesions focal to the left medio-dorsal nuclei for immediate and delayed memory performance on standard visual and verbal tests of anterograde memory, and over the long-term (> 24 hrs on an object-location associative memory task. Thalamic patients showed selective impairment to delayed recall, but intact recognition memory. Patients also showed accelerated forgetting of contextual information after a 24 hour delay, compared to controls. Importantly, the mammillothalamic tract was intact in all patients, which suggests a role for the medio-dorsal nuclei in recall and early consolidation memory processes.

  15. Gemcitabine, cisplatin, and hyperfractionated accelerated radiotherapy for locally advanced non-small cell lung cancer.

    Science.gov (United States)

    Zwitter, Matjaz; Kovac, Viljem; Smrdel, Uros; Strojan, Primoz

    2006-09-01

    Due to potent radiosensitization and potential serious or fatal toxicity, concurrent gemcitabine and irradiation should only be applied within clinical trials. We here present experience from a phase I-II clinical trial for patients with locally advanced non-small cell lung cancer (NSCLC) treated with hyperfractionated accelerated radiotherapy and concurrent low-dose gemcitabine. Eligible patients had locally advanced inoperable NSCLC without pleural effusion, Eastern Cooperative Oncology Group performance status 0-1, were chemotherapy naïve and had no previous radiotherapy to the chest, and had adequate hematopoietic, liver, and kidney function. Routine brain computed tomography was not performed, and positron emission tomography/computed tomography was not available. Treatment consisted of three parts: induction chemotherapy with gemcitabine and cisplatin in standard doses, local treatment with concurrent chemotherapy and radiotherapy, and consolidation chemotherapy. Patients were irradiated with opposed AP-PA and oblique fields, using 2.5-D treatment planning. Although corrections for inhomogeneous tissue were made, volume of total lung receiving > or =20 Gy (V20) could not be determined. The trial started as phase I, aimed to determine the dose-limiting toxicity and maximal tolerated dose (MTD) for concurrent hyperfractionated radiotherapy (1.4 Gy twice daily) and gemcitabine 55 mg/m twice weekly as a radiosensitizer. Phase II of the trial then continued at the level of MTD. Twenty-eight patients with NSCLC, nine patients with stage IIIA, 16 patients with IIIB, and three patients with an inoperable recurrence after previous surgery, entered the trial. The first 12 patients entered Phase I of the trial at the initial level of 42 Gy in 30 fractions in 3 weeks. Dose-limiting toxicity was acute esophagitis; 47.6 Gy in 34 fractions in 3.5 weeks was the MTD for this regimen of concurrent chemotherapy and radiotherapy. In phase II of the trial, this dose was applied

  16. Experimental study of collective acceleration of light and heavy ions from a localized gas cloud

    International Nuclear Information System (INIS)

    Floyd, L.E. IV.

    1984-01-01

    An experimental investigation into the collective acceleration of various gaseous atoms (H, D, He, N, Ne, Ar, Kr, Xe) is presented. A localized gas cloud is formed using a fast rise puff valve immediately downstream of an intense relativistic electron beam diode. The diode consists of a tungsten needle cathode and a stainless steel anode with a hole on axis. The diode is driven by an electron beam generator system consisting of a Marx generator, Blumlein line, and transmission line transformer. It produces a 1.5 MV, 35 kA, 30 ns FWHM electrical pulse measured at the diode. The resulting electron beam has nu/γ approx. 1 and is about six times the vacuum space charge limiting current in the downstream drift chamber. Ions are produced during the impact of the electron beam with the gas cloud and are accelerated to high energy by collective effects associated with the electron beam space charge. Ion energy diagnostics include fast neutron counting, nuclear activation of stacked foils, measurement of time of flight using direct intercept current collector probes, and range/energy analysis of nuclear track plates. The principal result of the experiments was that all ion species were accelerated to a maximum velocity of 0.1c, corresponding to an energy of 4.7 MeV/nucleon. Energy spectra obtained from stacked foil activation for accelerated hydrogen and deuterium were found to be approximately exponential in character

  17. Probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies.

    Science.gov (United States)

    Niikura, Takahito; Yamamoto, Izumi; Nakada, Yasuyuki; Kamejima, Sahoko; Katsumata, Haruki; Yamakawa, Takafumi; Furuya, Maiko; Mafune, Aki; Kobayashi, Akimitsu; Tanno, Yudo; Miki, Jun; Yamada, Hiroki; Ohkido, Ichiro; Tsuboi, Nobuo; Yamamoto, Hiroyasu; Yokoo, Takashi

    2015-07-01

    We report a case of probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies. A 44 year-old male was admitted to our hospital for a kidney transplant. The donor, his wife, was an ABO minor mismatch (blood type O to A) and had Gitelman syndrome. Graft function was delayed; his serum creatinine level was 10.1 mg/dL at 3 days after transplantation. Open biopsy was performed immediately; no venous thrombosis was observed during surgery. Histology revealed moderate peritubular capillaritis and mild glomerulitis without C4d immunoreactivity. Flow cytometric crossmatching was positive, but no panel-reactive antibodies against HLA or donor-specific antibodies (DSAbs) to major histocompatibility complex class I-related chain A (MICA) were detected. Taken together, we diagnosed him with probable C4d-negative accelerated antibody-mediated rejection due to non-HLA, non-MICA antibodies, the patient was treated with steroid pulse therapy (methylprednisolone 500 mg/day for 3 days), plasma exchange, intravenous immunoglobulin (40 g/body), and rituximab (200 mg/body) were performed. Biopsy at 58 days after transplantation, at which time S-Cr levels were 1.56 mg/dL, found no evidence of rejection. This case, presented with a review of relevant literature, demonstrates that probable C4d-negative accelerated acute AMR can result from non-HLA antibodies. © 2015 Asian Pacific Society of Nephrology.

  18. Localized saddle-point search and application to temperature-accelerated dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Yunsic; Amar, Jacques G. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Callahan, Nathan B. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States)

    2013-03-07

    We present a method for speeding up temperature-accelerated dynamics (TAD) simulations by carrying out a localized saddle-point (LSAD) search. In this method, instead of using the entire system to determine the energy barriers of activated processes, the calculation is localized by only including a small chunk of atoms around the atoms directly involved in the transition. Using this method, we have obtained N-independent scaling for the computational cost of the saddle-point search as a function of system size N. The error arising from localization is analyzed using a variety of model systems, including a variety of activated processes on Ag(100) and Cu(100) surfaces, as well as multiatom moves in Cu radiation damage and metal heteroepitaxial growth. Our results show significantly improved performance of TAD with the LSAD method, for the case of Ag/Ag(100) annealing and Cu/Cu(100) growth, while maintaining a negligibly small error in energy barriers.

  19. Measuring localized nonlinear components in a circular accelerator with a nonlinear tune response matrix

    Directory of Open Access Journals (Sweden)

    G. Franchetti

    2008-09-01

    Full Text Available In this paper we present a method for measuring the nonlinear errors in a circular accelerator by taking advantage of the feed-down effect of high order multipoles when the closed orbit is globally deformed. We devise a nonlinear tune response matrix in which the response to a closed orbit deformation is obtained in terms of change of machine tune and correlated with the strength of the local multipoles. A numerical example and a proof of principle experiment to validate the theoretical methods are presented and discussed.

  20. Expected damage to accelerator equipment due to the impact of the full LHC beam: beam instrumentation, experiments and simulations

    CERN Document Server

    Burkart, Florian

    The Large Hadron Collider (LHC) is the biggest and most powerful particle accelerator in the world, designed to collide two proton beams with particle momentum of 7 TeV/c each. The stored energy of 362MJ in each beam is sufficient to melt 500 kg of copper or to evaporate about 300 liter of water. An accidental release of even a small fraction of the beam energy can cause severe damage to accelerator equipment. Reliable machine protection systems are necessary to safely operate the accelerator complex. To design a machine protection system, it is essential to know the damage potential of the stored beam and the consequences in case of a failure. One (catastrophic) failure would be, if the entire beam is lost in the aperture due to a problem with the beam dumping system. This thesis presents the simulation studies, results of a benchmarking experiment, and detailed target investigation, for this failure case. In the experiment, solid copper cylinders were irradiated with the 440GeV proton beam delivered by the ...

  1. Resonance localization and poloidal electric field due to cyclo- tron wave heating in tokamak plasmas

    International Nuclear Information System (INIS)

    Hsu, J.Y.; Chan, V.S.; Harvey, R.W.; Prater, R.; Wong, S.K.

    1984-01-01

    The perpendicular heating in cyclotron waves tends to pile up the resonant particles toward the low magnetic field side with their banana tips localized to the resonant surface. A poloidal electric field with an E x B drift comparable to the ion vertical drift in a toroidal magnetic field may result. With the assumption of anomalous electron and neoclassical ion transport, density variations due to wave heating are discussed

  2. Acceleration of Medpor implant fibrovascularization with local vascular endothelial growth-factor injections: An experimental study

    Directory of Open Access Journals (Sweden)

    Mert Demirel

    2015-12-01

    Full Text Available Objective: Medpor is a biocompatible, high-density porous polyethylene implant that is used for multiple indications in plastic surgery. The most frequent complications associated with the Medpor implant are infection and implant exposure. The primary cause of these complications is poor fibrovascularization of the Medpor implant and poor nourishment of the overlying skin. The present experimental study aimed to determine whether vascular endothelial growth factor (VEGF could accelerate and increase Medpor implant fibrovascularization in vivo, and thereby improve local nourishment and prevent complications. Materials and Methods: The Medpor implant was inserted under the dorsal skin area in 40 Sprague-Dawley rats. 20 rats receiving local VEGF injections comprised the study group. The control group received saline injections. Fibrovascularization of the Medpor implants was compared. Results: In the rats injected with VEGF, the Medpor implant fibrovascularized faster, and there were more newly formed blood vessels, as compared with those in the control group. Conclusion: These findings have led to our use of VEGF-like agents that the accelerate angiogenesis in the Medpor implant as a means to reduce the incidence of such complications as infection and implant exposure. [Arch Clin Exp Surg 2015; 4(4.000: 196-201

  3. Accelerated superfractionated radiotherapy with concomitant boost for locally advanced head-and-neck squamous cell carcinomas

    International Nuclear Information System (INIS)

    Morris, Monica M.; Schmidt-Ullrich, Rupert K.; DiNardo, L.; Manning, Matthew A.; Silverman, L.; Clay, L.; Johnson, Christopher R.; Amir, Cyrus

    2002-01-01

    Purpose: A growing body of evidence supports the efficacy of accelerated superfractionated radiotherapy with concomitant boost for advanced head-and-neck carcinomas. This study represents a single-institution experience, performed to identify the factors influencing tumor control, survival, and toxicity. Methods and Materials: Between 1988 and 1999, 133 patients with primary squamous cell head-and-neck carcinoma underwent accelerated superfractionated radiotherapy using a concomitant boost. The concomitant boost in this regimen was delivered using reduced fields delivered 3 times weekly in a twice-daily schedule during the final phase. The total radiation dose ranged from 64.8 Gy to 76.5 Gy (mean 71.1). Patients were evaluated in follow-up for local control and late toxicity. Multivariate analysis of treatment and patient parameters was performed to evaluate their influence on toxicity, local control, and overall survival. Results: With a mean follow-up of 37 months, the actuarial overall survival rate for the entire group at 5 years was 24% and the local control rate was 57%. The tumor volume was the most significant predictor of local control, such that each 1-cm 3 increase in volume was associated with a 1% decrease in local control. For patients with tumor volumes ≤30 cm 3 vs. >30 cm 3 , the 5-year disease-specific survival rate was 52% and 27% (p = 0.004) and locoregional control rate was 76% and 26% (p<0.001), respectively. Seventy-six patients with a minimum of 12 months and median of 39 months toxicity follow-up were studied for late effects. None of these patients experienced Grade 4 or 5 toxicity. The actuarial rate of significant toxicity (Grade III or greater) was 32% at 5 years. Of the toxicities observed, xerostomia (19%) was the most common. Multivariate analysis revealed N stage and dose as independent predictors of Grade 3 effects. Conclusion: The locoregional control and survival for patients in this institutional experience compare favorably to

  4. Localized demodicosis due to Demodex cati on the muzzle of two cats treated with inhalant glucocorticoids.

    Science.gov (United States)

    Bizikova, Petra

    2014-06-01

    Feline demodicosis due to Demodex cati is a rare skin disease often associated with concurrent disease and generalized immunosuppression. Local immunosuppression due to the application of topical immunomodulatory drugs, such as glucocorticoids and tacrolimus, or by tumour cells has been suggested as a potential trigger for development of localized demodicosis in humans and animals. The goal was to describe two cats with asthma that developed localized demodicosis on the muzzle as a result of chronic therapy with a glucocorticoid administered via dispensing inhaler mask. In both cats, the muzzle area exposed to the fluticasone-dispensing chamber exhibited patchy alopecia, mild erythema, crusting and scaling. Deep skin scraping revealed D. cati. Discontinuation or reduction of fluticasone and administration of milbemycin resulted in resolution of clinical signs within 2 months in both cats. A negative skin scrape was obtained after 7 months of milbemycin in one of the cats. Demodicosis should be considered as a possible differential diagnosis in cats with primary alopecia or other skin lesions on the face exposed to inhalant glucocorticoids. Minimization of contact between the inhalant glucocorticoid and the skin can be achieved by wiping residual powder from the face and by keeping the mask tightly pressed to the skin to avoid contact with the surrounding area. © 2014 ESVD and ACVD.

  5. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    Science.gov (United States)

    Bandriyana, B.; Utaja

    2010-06-01

    Thermal stratification introduces thermal shock effect which results in local stress and fatique problems that must be considered in the design of nuclear power plant components. Local stress and fatique calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343° C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  6. The peculiar acceleration of the Local Group as deduced from the optical and IRAS flux dipoles

    International Nuclear Information System (INIS)

    Lahav, O.; Lynden-Bell, D.

    1988-01-01

    The relation between the peculiar acceleration of the Local Group and the surface brightness dipole moments of all-sky optical and IRAS samples is studied. Our revised optical dipole lies within 7 0 of the direction of the Local Group's motion through the Microwave Background Radiation (MBR). The directions of the optical, IRAS and MBR dipoles are all consistent with each other. To analyse the optical dipole we have calculated diameter functions for the UGC and ESO galaxy catalogues from redshift surveys. Most of the optical dipole arises from the Centaurus-Virgo direction and from the 'Local Void' on the opposite side of the sky. The sources of the IRAS dipole are more evenly distributed around the sky. A simple 'shell model', fitted to the variation of the dipoles as a function of flux, suggests that the dipoles arise from galaxies whose recession velocities are smaller than 4000 kms -1 . We find a high Ω 0 value for the IRAS sample and a low one for the optical sample. These results may be reconciled if the optical galaxy distribution is more biased relative to the matter distribution than the IRAS galaxy distribution. (author)

  7. Accelerated cardiac cine MRI using locally low rank and finite difference constraints.

    Science.gov (United States)

    Miao, Xin; Lingala, Sajan Goud; Guo, Yi; Jao, Terrence; Usman, Muhammad; Prieto, Claudia; Nayak, Krishna S

    2016-07-01

    To evaluate the potential value of combining multiple constraints for highly accelerated cardiac cine MRI. A locally low rank (LLR) constraint and a temporal finite difference (FD) constraint were combined to reconstruct cardiac cine data from highly undersampled measurements. Retrospectively undersampled 2D Cartesian reconstructions were quantitatively evaluated against fully-sampled data using normalized root mean square error, structural similarity index (SSIM) and high frequency error norm (HFEN). This method was also applied to 2D golden-angle radial real-time imaging to facilitate single breath-hold whole-heart cine (12 short-axis slices, 9-13s single breath hold). Reconstruction was compared against state-of-the-art constrained reconstruction methods: LLR, FD, and k-t SLR. At 10 to 60 spokes/frame, LLR+FD better preserved fine structures and depicted myocardial motion with reduced spatio-temporal blurring in comparison to existing methods. LLR yielded higher SSIM ranking than FD; FD had higher HFEN ranking than LLR. LLR+FD combined the complimentary advantages of the two, and ranked the highest in all metrics for all retrospective undersampled cases. Single breath-hold multi-slice cardiac cine with prospective undersampling was enabled with in-plane spatio-temporal resolutions of 2×2mm(2) and 40ms. Highly accelerated cardiac cine is enabled by the combination of 2D undersampling and the synergistic use of LLR and FD constraints. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Local impact effects on concrete target due to missile: An empirical and numerical approach

    International Nuclear Information System (INIS)

    Ranjan, Rajiv; Banerjee, Sauvik; Singh, R.K.; Banerji, Pradipta

    2014-01-01

    Highlights: • Local impact effect of hard missile on reinforced concrete targets has been studied. • Review of empirical formulation for predicting local response carried out. • Numerical simulation of experimental test of Kojima (1991) carried out. • Divergence of FE results with those obtained using emperical formulations. • Close match of numerical simulation results with experimental data. - Abstract: Concrete containment walls and internal concrete barrier walls of a Nuclear Power Plant safety related structures are often required to be designed for externally and internally generated missiles. Potential missiles include external extreme wind generated missiles, aircraft crash and internal accident generated missiles such as impact due to turbine blade failure and steel pipe missiles resulting from pipe break. The objective of the present paper is to compare local missile impact effects on reinforced concrete target using available empirical formulations with those obtained using LS-DYNA numerical simulation. The use of numerical simulations for capturing the transient structural response has become increasingly used for structural design against impact loads. They overcome the limits of applicability of the empirical formulae and also provide information on stress and deformation fields, which may be used to improve the resistance of the concrete. Finite element (FE) analyses of an experimental impact problem reported by Kojima (1991) are carried out that are able to capture the missile impact effects; in terms of local and global damage. The continuous surface cap model has been used for modelling concrete behaviour. A range of missile velocity has been considered to simulate local missile impact phenomenon and modes of failure and to capture the concrete response from elastic to plastic fracture. A comparison is then made between the empirical formulations, numerical simulation results, and available experimental results of slab impact tests

  9. Accelerated Enveloping Distribution Sampling: Enabling Sampling of Multiple End States while Preserving Local Energy Minima.

    Science.gov (United States)

    Perthold, Jan Walther; Oostenbrink, Chris

    2018-05-17

    Enveloping distribution sampling (EDS) is an efficient approach to calculate multiple free-energy differences from a single molecular dynamics (MD) simulation. However, the construction of an appropriate reference-state Hamiltonian that samples all states efficiently is not straightforward. We propose a novel approach for the construction of the EDS reference-state Hamiltonian, related to a previously described procedure to smoothen energy landscapes. In contrast to previously suggested EDS approaches, our reference-state Hamiltonian preserves local energy minima of the combined end-states. Moreover, we propose an intuitive, robust and efficient parameter optimization scheme to tune EDS Hamiltonian parameters. We demonstrate the proposed method with established and novel test systems and conclude that our approach allows for the automated calculation of multiple free-energy differences from a single simulation. Accelerated EDS promises to be a robust and user-friendly method to compute free-energy differences based on solid statistical mechanics.

  10. Two-Body Orbit Expansion Due to Time-Dependent Relative Acceleration Rate of the Cosmological Scale Factor

    Directory of Open Access Journals (Sweden)

    Lorenzo Iorio

    2014-01-01

    Full Text Available By phenomenologically assuming a slow temporal variation of the percent acceleration rate S̈S -1 of the cosmic scale factor S(t, it is shown that the orbit of a local binary undergoes a secular expansion. To first order in the power expansion of S̈S -1 around the present epoch t0, a non-vanishing shift per orbit (Δr of the two-body relative distance r occurs for eccentric trajectories. A general relativistic expression, which turns out to be cubic in the Hubble parameter H0 at the present epoch, is explicitly calculated for it in the case of matter-dominated epochs with Dark Energy. For a highly eccentric Oort comet orbit with period Pb ≈ 31 Myr, the general relativistic distance shift per orbit turns out to be of the order of (Δr ≈ 70 km. For the Large Magellanic Cloud, assumed on a bound elliptic orbit around the Milky Way, the shift per orbit is of the order of (Δr ≈ 2–4 pc. Our result has a general validity since it holds in any cosmological model admitting the Hubble law and a slowly varying S̈S-1(t. More generally, it is valid for an arbitrary Hooke-like extra-acceleration whose “elastic” parameter κ is slowly time-dependent, irrespectively of the physical mechanism which may lead to it. The coefficient κ1 of the first-order term of the power expansion of κ(t can be preliminarily constrained in a model-independent way down to a κ1 ≲ 2 x 10-13 year-3 level from latest Solar System’s planetary observations. The radial velocities of the double lined spectroscopic binary ALPHA Cen AB yield κ1 ≲ 10-8 year-3.

  11. Mass transfer coefficient in disturbed flow due to orifice for flow accelerated corrosion in nuclear power plant

    International Nuclear Information System (INIS)

    Prasad, Mahendra; Gaikwad, Avinash J.; Sridharan, Arunkumar; Parida, Smrutiranjan

    2015-01-01

    The flow of fluid in pipes cause corrosion wherein the inner surface of pipe becomes progressively thinner and susceptible to failure. This form of corrosion dependent on flow dynamics is called Flow Accelerated Corrosion (FAC) and has been observed in Nuclear Power Plants (NPPs). Mass transfer coefficient (MTC) is related to extent of wall thinning and it changes from its value in a straight pipe (with same fluid parameters) for flow in orifices, bends, junctions etc. due to gross disturbance of the velocity profile. This paper presents two-dimensional computational fluid dynamics (CFD) simulations for an orifice configuration in a straight pipe. Turbulent model K- ω with shear stress transport and transition flow was the model used for simulation studies. The mass transfer boundary layer (MTBL) thickness δ mtbl is related to the Schmidt number (Sc) and hydrodynamic boundary layer thickness δ h , as δ mtbl ~ δh/(Sc 1/3 ). MTBL is significantly smaller than δ h and hence boundary layer meshing was carried out deep into δ mtbl . Uniform velocity profile was applied at the inlet. Post orifice fluid shows large recirculating flows on the upper and lower wall. At various locations after orifice, mass transfer coefficient is calculated and compared with the value in straight pipe with fully developed turbulent flow. The MTC due to the orifice increases and it is correlated with enhanced FAC in region after orifice. (author)

  12. Localized irradiation of mouse legs using an image-guided robotic linear accelerator.

    Science.gov (United States)

    Kufeld, Markus; Escobar, Helena; Marg, Andreas; Pasemann, Diana; Budach, Volker; Spuler, Simone

    2017-04-01

    To investigate the potential of human satellite cells in muscle regeneration small animal models are useful to evaluate muscle regeneration. To suppress the inherent regeneration ability of the tibialis muscle of mice before transplantation of human muscle fibers, a localized irradiation of the mouse leg should be conducted. We analyzed the feasibility of an image-guided robotic irradiation procedure, a routine treatment method in radiation oncology, for the focal irradiation of mouse legs. After conducting a planning computed tomography (CT) scan of one mouse in its customized mold a three-dimensional dose plan was calculated using a dedicated planning workstation. 18 Gy have been applied to the right anterior tibial muscle of 4 healthy and 12 mice with immune defect in general anesthesia using an image-guided robotic linear accelerator (LINAC). The mice were fixed in a customized acrylic mold with attached fiducial markers for image guided tracking. All 16 mice could be irradiated as prevised without signs of acute radiation toxicity or anesthesiological side effects. The animals survived until scarification after 8, 21 and 49 days as planned. The procedure was straight forward and the irradiation process took 5 minutes to apply the dose of 18 Gy. Localized irradiation of mice legs using a robotic LINAC could be conducted as planned. It is a feasible procedure without recognizable side effects. Image guidance offers precise dose delivery and preserves adjacent body parts and tissues.

  13. Retarded Local Dynamics of Single Fluorescent Probes in Polymeric Glass due to Interaction Strengthening

    Science.gov (United States)

    Zhang, Hao; Yang, Jingfa; Zhao, Jiang

    The effect of strengthening of interaction between single fluorescent probes and polymer matrix to the probes dynamics is investigated using single molecule fluorescence defocus microscopy. By introducing multiple hydroxyl groups to the fluorescent probes, which builds up hydrogen bonds between the probe and polymer matrix, the dynamics is discovered to be retarded. This is evidenced by the lowering of the frequency of the vibrational modes in the power spectra of the rotation trajectories of individual fluorescent probes, and also by the lowering of population of rotating probes. The results show that by strengthening the probe-matrix interaction, the local dynamics detected by the probes is equivalent to that detected by a bigger probe, due to the enhanced friction between the probe and the polymer matrix. the National Basic Research Program of China (2012CB821500).

  14. Universal behavior of magnetoconductance due to weak localization in two dimensions

    Science.gov (United States)

    Zduniak, A.; Dyakonov, M. I.; Knap, W.

    1997-07-01

    Magnetoconductance due to weak localization is studied experimentally for different semiconductor heterostructures. We observe that, when presented as a function of the appropriately normalized magnetic field, different samples show very similar high-field behavior. A theoretical description is developed that allows one to describe in a consistent way both the high- and low-field limits. The theory predicts universal magnetic field dependence (B-1/2) of the conductivity correction for two-dimensional systems in the high-field limit. Low-field magnetoconductance depends strongly on spin and phase relaxation processes. Comparison of the theory with experiment confirms the universal behavior in high fields and allows one to estimate the spin and phase relaxation times.

  15. Extreme concentration fluctuations due to local reversibility of mixing in turbulent flows

    Science.gov (United States)

    Xia, Hua; Francois, Nicolas; Punzmann, Horst; Szewc, Kamil; Shats, Michael

    2018-05-01

    Mixing of a passive scalar in a fluid (e.g. a radioactive spill in the ocean) is the irreversible process towards homogeneous distribution of a substance. In a moving fluid, due to the chaotic advection [H. Aref, J. Fluid Mech. 143 (1984) 1; J. M. Ottino, The Kinematics of Mixing: Stretching,Chaos and Transport (Cambridge University Press, Cambridge, 1989)] mixing is much faster than if driven by molecular diffusion only. Turbulence is known as the most efficient mixing flow [B. I. Shraiman and E. D. Siggia, Nature 405 (2000) 639]. We show that in contrast to spatially periodic flows, two-dimensional turbulence exhibits local reversibility in mixing, which leads to the generation of unpredictable strong fluctuations in the scalar concentration. These fluctuations can also be detected from the analysis of the fluid particle trajectories of the underlying flow.

  16. 3-D inversion of airborne electromagnetic data parallelized and accelerated by local mesh and adaptive soundings

    Science.gov (United States)

    Yang, Dikun; Oldenburg, Douglas W.; Haber, Eldad

    2014-03-01

    Airborne electromagnetic (AEM) methods are highly efficient tools for assessing the Earth's conductivity structures in a large area at low cost. However, the configuration of AEM measurements, which typically have widely distributed transmitter-receiver pairs, makes the rigorous modelling and interpretation extremely time-consuming in 3-D. Excessive overcomputing can occur when working on a large mesh covering the entire survey area and inverting all soundings in the data set. We propose two improvements. The first is to use a locally optimized mesh for each AEM sounding for the forward modelling and calculation of sensitivity. This dedicated local mesh is small with fine cells near the sounding location and coarse cells far away in accordance with EM diffusion and the geometric decay of the signals. Once the forward problem is solved on the local meshes, the sensitivity for the inversion on the global mesh is available through quick interpolation. Using local meshes for AEM forward modelling avoids unnecessary computing on fine cells on a global mesh that are far away from the sounding location. Since local meshes are highly independent, the forward modelling can be efficiently parallelized over an array of processors. The second improvement is random and dynamic down-sampling of the soundings. Each inversion iteration only uses a random subset of the soundings, and the subset is reselected for every iteration. The number of soundings in the random subset, determined by an adaptive algorithm, is tied to the degree of model regularization. This minimizes the overcomputing caused by working with redundant soundings. Our methods are compared against conventional methods and tested with a synthetic example. We also invert a field data set that was previously considered to be too large to be practically inverted in 3-D. These examples show that our methodology can dramatically reduce the processing time of 3-D inversion to a practical level without losing resolution

  17. Anisotropic light emission of single CdSe/CdS tetrapods due to asymmetric electron localization

    Energy Technology Data Exchange (ETDEWEB)

    Limmer, Thomas; Mauser, Christian; Como, Enrico da; Rogach, Andrey; Feldmann, Jochen [Photonics and Optoelectronics Group, Physics Department and CeNS, Ludwig-Maximilians-Universitaet Muenchen, Munich (Germany); Talapin, Dmitri V. [Department of Chemistry, University of Chicago, Chicago, IL (United States)

    2008-07-01

    We have recently reported on highly luminescent CdSe/CdS tetrapod heterostructures, where wurtzite CdS arms were grown on CdSe zinc-blend nuclei. Due to the peculiar energy band alignment the holes remain trapped in the CdSe core, whereas electrons in ideal tetrapods are expected to delocalize symmetrically into the four CdS arms. However, polarization dependent photoluminescence experiments on single tetrapods show asymmetric localization effects for electrons. Whereas in optical excitation nearly no polarization anisotropy is observed, high polarization degrees are present in the emission process. Calculations based on the effective mass approximation show that the electron wavefunction confinement is very sensitive to changes in the shape of the tetrapods. Breaking the symmetry by increasing the thickness of one arm gives rise to a strongly asymmetric localization of the electron and leads to high polarization degrees in emission. The related decrease in electron-hole wavefunction overlap results in a correlation between emission intensity and polarization anisotropy in agreement with our experimental findings.

  18. The acceleration of dissolved cobalt's ecological stoichiometry due to biological uptake, remineralization, and scavenging in the Atlantic Ocean

    Science.gov (United States)

    Saito, Mak A.; Noble, Abigail E.; Hawco, Nicholas; Twining, Benjamin S.; Ohnemus, Daniel C.; John, Seth G.; Lam, Phoebe; Conway, Tim M.; Johnson, Rod; Moran, Dawn; McIlvin, Matthew

    2017-10-01

    The stoichiometry of biological components and their influence on dissolved distributions have long been of interest in the study of the oceans. Cobalt has the smallest oceanic inventory of inorganic micronutrients and hence is particularly vulnerable to influence by internal oceanic processes including euphotic zone uptake, remineralization, and scavenging. Here we observe not only large variations in dCo : P stoichiometry but also the acceleration of those dCo : P ratios in the upper water column in response to several environmental processes. The ecological stoichiometry of total dissolved cobalt (dCo) was examined using data from a US North Atlantic GEOTRACES transect and from a zonal South Atlantic GEOTRACES-compliant transect (GA03/3e and GAc01) by Redfieldian analysis of its statistical relationships with the macronutrient phosphate. Trends in the dissolved cobalt to phosphate (dCo : P) stoichiometric relationships were evident in the basin-scale vertical structure of cobalt, with positive dCo : P slopes in the euphotic zone and negative slopes found in the ocean interior and in coastal environments. The euphotic positive slopes were often found to accelerate towards the surface and this was interpreted as being due to the combined influence of depleted phosphate, phosphorus-sparing (conserving) mechanisms, increased alkaline phosphatase metalloenzyme production (a zinc or perhaps cobalt enzyme), and biochemical substitution of Co for depleted Zn. Consistent with this, dissolved Zn (dZn) was found to be drawn down to only 2-fold more than dCo, despite being more than 18-fold more abundant in the ocean interior. Particulate cobalt concentrations increased in abundance from the base of the euphotic zone to become ˜ 10 % of the overall cobalt inventory in the upper euphotic zone with high stoichiometric values of ˜ 400 µmol Co mol-1 P. Metaproteomic results from the Bermuda Atlantic Time-series Study (BATS) station found cyanobacterial isoforms of the

  19. THREE-DIMENSIONAL NON-VACUUM PULSAR OUTER-GAP MODEL: LOCALIZED ACCELERATION ELECTRIC FIELD IN THE HIGHER ALTITUDES

    Energy Technology Data Exchange (ETDEWEB)

    Hirotani, Kouichi [Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA), P.O. Box 23-141, Taipei, Taiwan (China)

    2015-01-10

    We investigate the particle accelerator that arises in a rotating neutron-star magnetosphere. Simultaneously solving the Poisson equation for the electro-static potential, the Boltzmann equations for relativistic electrons and positrons, and the radiative transfer equation, we demonstrate that the electric field is substantially screened along the magnetic field lines by pairs that are created and separated within the accelerator. As a result, the magnetic-field-aligned electric field is localized in higher altitudes near the light cylinder and efficiently accelerates the positrons created in the lower altitudes outward but does not accelerate the electrons inward. The resulting photon flux becomes predominantly outward, leading to typical double-peak light curves, which are commonly observed from many high-energy pulsars.

  20. Hyperfractionated-accelerated radiotherapy followed by radical surgery in locally advanced tumors of the oral cavity

    International Nuclear Information System (INIS)

    Hoeller, U.; Biertz, I.; Tribius, S.; Alberti, W.; Flinzberg, S.; Schmelzle, R.

    2006-01-01

    Purpose: to evaluate the outcome of hyperfractionated-accelerated radiotherapy and subsequent planned primary tumor resection and radical neck dissection in locally advanced tumors of the oral cavity. Patients and Methods: this retrospective analysis evaluates 126 subsequent patients who were treated between 1988 and 1997 for locally advanced tumors of the oral cavity (with extension into the oropharynx in 17 patients), 34 (27%) AJCC stage III and 92 (73%) stage IV. Primary tumor and nodal metastases were irradiated with 1.4 Gy bid to a median total dose of 72.8 Gy (range 58.8-75.6 Gy). Then, planned radical surgery of the primary site according to the initial tumor extent and cervical nodes was performed. Median follow-up of living patients was 6 years (range 1-11 years). Results: 4 weeks after radiotherapy, 14 patients (11%) had complete tumor remission, 92 (73%) partial remission, 15 (12%) no change, and five (4%) progressive disease. Complete resection was achieved in 117 (93%) patients (nine incomplete resections). 5-year locoregional control rate was 62 ± 9%, overall survival 36 ± 9%. Surgery-related morbidity occurred in 42 patients (33%; mainly delayed wound healing and fistulae), overall severe treatment-related morbidity in 46 patients (36%). 24/84 relapse-free patients (29%) required a percutaneous gastrostomy or nasal tube ≥ 1 year after therapy. Conclusion: in this study, the outcome of combined curative radiotherapy and planned surgery of the primary tumor and neck nodes was comparable to reported results of hyperfractionated radiotherapy with or without salvage surgery of the neck nodes with respect to locoregional control and overall survival. Planned surgery carries a substantial risk of morbidity and seems to offer no benefit in comparison to salvage surgery of the neck nodes only. Therefore, salvage surgery is preferred. (orig.)

  1. Local administration of a hedgehog agonist accelerates fracture healing in a mouse model

    International Nuclear Information System (INIS)

    Kashiwagi, Miki; Hojo, Hironori; Kitaura, Yoshiaki; Maeda, Yujiro; Aini, Hailati; Takato, Tsuyoshi; Chung, Ung-il; Ohba, Shinsuke

    2016-01-01

    Bone fracture healing is processed through multiple biological stages including the transition from cartilaginous callus to bony callus formation. Because of its specific, temporal and indispensable functions demonstrated by mouse genetic studies, Hedgehog (Hh) signaling is one of the most potent signaling pathways involved in these processes, but the effect of Hh-signaling activation by small compounds on the repair process had not yet been addressed. Here we examined therapeutic effects of local and one shot-administration of the Hh agonist known as smoothened agonist (SAG) on bone fracture healing in a mouse model. A quantitative analysis with three-dimensional micro-computed tomography showed that SAG administration increased the size of both the cartilaginous callus and bony callus at 14 days after the surgery. A histological analysis showed that SAG administration increased the number of cells expressing a proliferation marker and a chondrocyte marker in cartilaginous callus as well as the cells expressing an osteoblast marker in bony callus. These results indicate that the SAG administration resulted in an enhancement of callus formation during bone fracture healing, which is at least in part mediated by an increase in chondrocyte proliferation in cartilaginous callus and the promotion of bone formation in bony callus. Therapeutic strategies with a SAG-mediated protocol may thus be useful for the treatment of bone fractures. - Highlights: • Local administration of a Hh agonist accelerates callus formation. • The Hh agonist administration promotes chondrocyte proliferation in the soft callus. • The Hh agonist administration increases osteoblast formation in the hard callus.

  2. A fiber-optic strain measurement and quench localization system for use in superconducting accelerator dipole magnets

    NARCIS (Netherlands)

    van Oort, J.M.; Scanlan, Ronald M.; ten Kate, Herman H.J.

    1995-01-01

    A novel fiber-optic measurement system for superconducting accelerator magnets is described. The principal component is an extrinsic Fabry-Perot interferometer to determine localized strain and stress in coil windings. The system can be used either as a sensitive relative strain measurement system

  3. Severe Bradycardia Possibly due to a Local Anesthetic Oral Mucosal Injection during General Anesthesia

    OpenAIRE

    Satoh, Kenichi; Ohashi, Ayako; Kumagai, Miho; Hoshi, Hideki; Otaka, Kousei; Joh, Shigeharu

    2015-01-01

    Local anesthesia may induce systemic complications leading to parasympathetic activity leading to bradycardia and hypotension. We report a case of a 50-year-old man undergoing dental surgery under general anesthesia who experienced severe bradycardia and hypotension after local anesthesia infiltration. Concerns regarding the utilization of a relatively large lumen injection needle for local anesthesia during general anesthesia are discussed.

  4. Variation Process of Radiation Belt Electron Fluxes due to Interaction With Chorus and EMIC Rising-tone Emissions Localized in Longitude

    Science.gov (United States)

    Kubota, Y.; Omura, Y.

    2017-12-01

    Using results of test particle simulations of a large number of electrons interacting with a pair of chorus emissions, we create Green's functions to model the electron distribution function after all of the possible interactions with the waves [Omura et al., 2015]. Assuming that the waves are generated in a localized range of longitudes in the dawn side, we repeat taking the convolution integral of the Green's function with the distribution function of the electrons injected into the generation region of the localized waves. From numerical and theoretical analyses, we find that electron acceleration process only takes place efficiently below 4 MeV. Because extremely relativistic electrons go through the wave generation region rapidly due to grad-B0 and curvature drift, they don't have enough interaction time to be accelerated. In setting up the electrons after all interaction with chorus emissions as initial electron distribution function, we also compute the loss process of radiation belt electron fluxes due to interaction with EMIC rising-tone emissions generated in a localized range of longitudes in the dusk side [Kubota and Omura,2017]. References: (1) Omura, Y., Y. Miyashita, M. Yoshikawa, D. Summers, M. Hikishima, Y. Ebihara, and Y. Kubota (2015), Formation process of relativistic electron flux through interaction with chorus emissions in the Earth's inner magnetosphere, J. Geophys. Res. Space Physics, 120, 9545-9562, doi:10.1002/2015JA021563. (2) Kubota, Y., and Y. Omura (2017), Rapid precipitation of radiation belt electrons induced by EMIC rising tone emissions localized in longitude inside and outside the plasmapause, J. Geophys. Res. Space Physics, 122, 293-309, doi:10.1002/2016JA023267.

  5. Think Local-Act Local: Is It Time to Slow Down the Accelerated Move to Global Marketing?

    OpenAIRE

    Schuiling, Isabelle

    2001-01-01

    In view of the accelerated move of great corporations towards global marketing, the strategic changes of such companies raise interesting questions. Is marketing globalization reaching its limits after years of implementation? Is it time for companies to rethink their strategies and move back, like Coca-Cola, to a multi-domestic marketing approach?

  6. Anomalous resistivity due to low-frequency turbulence. [of collisionless plasma with limited acceleration of high velocity runaway electrons

    Science.gov (United States)

    Rowland, H. L.; Palmadesso, P. J.

    1983-01-01

    Large amplitude ion cyclotron waves have been observed on auroral field lines. In the presence of an electric field parallel to the ambient magnetic field these waves prevent the acceleration of the bulk of the plasma electrons leading to the formation of a runaway tail. It is shown that low-frequency turbulence can also limit the acceleration of high-velocity runaway electrons via pitch angle scattering at the anomalous Doppler resonance.

  7. ACCELERATED HYPERFRACTIONATED RADIOTHERAPY IN THE TREATMENT FOR INOPERABLE, LOCALLY ADVANCED GASTRIC CANSER

    Directory of Open Access Journals (Sweden)

    S. S. Litinskiy

    2015-01-01

    Full Text Available Purpose: to compare survival of patients with locally advanced inoperable gastric cancer (LAIGC, receiving accelerated hyperfractionated (AHF or conventionally fractionated (CF radiation therapy (RT. Methods and Materials. Between November 1993 and March 2010, 137 patients with LAIGC receiving CF (2 Gy daily or AHF (1.3 Gy b.i.d. to total at least 50 Gy RT in combination or without chemotherapy were retrospectively selected from the hospital database of Arkhangelsk clinical oncological dispensary. Overall survival (OS assessed using actuarial analysis, Kaplan – Meier method and Cox regression. results. The CF and AHF groups were 102 and 35 patients, respectively. Median follow-up time for all patients was 12 years. By the time of analysis 123 (90 % patients of all cohort died. Median, 7-year survival were 24 (95 % confidence intervals (CI, 17–31 vs 16 (95 % CI, 11–21 months, hazard ratio (HR=0.71 (95 % CI, 0.46–1.06, р=0.097; and 19 % (95 % CI 8–34 % vs 6% (95 % CI 2–13 % in the AHF and CF groups, respectively. In multivariate OS model the difference decreased to HR=0.87 (95 % CI, 0.49–1.55. The location of the tumor in median third (HR=0.60, 95 % CI, 0.37–0.99 in refer to upper third was the only independent factor influencing survival.  There was no influence of the total dose in chosen level on survival. conclusion. Our retrospective shows trend towards better OS for those LAIGC patients receiving RT in AHF regimen compared to CF. The prospective randomized study with conformal radiation technics is necessary to confirm these findings.

  8. Development of a semi-automatic alignment tool for accelerated localization of the prostate

    International Nuclear Information System (INIS)

    Hua Chiaho; Lovelock, D. Michael; Mageras, Gikas S.; Katz, Matthew S.; Mechalakos, James; Lief, Eugene P.; Hollister, Timothy; Lutz, Wendell R.; Zelefsky, Michael J.; Ling, Clifton C.

    2003-01-01

    -fitting correction, 97% of the scans showed that the entire posterior prostate gland was covered by PTV given a margin of 6 mm at the rectum-prostate interface and 10 mm elsewhere. In comparison, only 74% and 65% could be achieved by the corrections based on daily and weekly bony matching on portal images, respectively. Conclusions: Results show that daily CT extent fitting provides a precise correction of prostate position in terms of CoG. Identifying prostate extents on five axial CT slices at the CT console is less time-consuming compared with daily contouring of the prostate on many slices. Taking advantage of the prostate curvature in the longitudinal direction, this method also eliminates the necessity of identifying prostate base and apex. Therefore, it is clinically feasible and should provide an accelerated localization of the prostate immediately before daily treatment

  9. Localization of ionization-induced trapping in a laser wakefield accelerator using a density down-ramp

    CERN Document Server

    Hansson, M.; Ekerfelt, H.; Aurand, B.; Gallardo Ganzalez, I.; Desforges, F. G.; Davoine, X.; Maitrallain, A.; Reymond, S.; Monot, P.; Persson, A.; Dobosz Dufrénoy S.; Wahlström C-G.; Cros, B.; Lundh, O.

    2016-01-01

    We report on a study on controlled trapping of electrons, by field ionization of nitrogen ions, in laser wakefield accelerators in variable length gas cells. In addition to ionization-induced trapping in the density plateau inside the cells, which results in wide, but stable, electron energy spectra, a regime of ionization-induced trapping localized in the density down-ramp at the exit of the gas cells, is found. The resulting electron energy spectra are peaked, with 10% shot-to-shot fluctuations in peak energy. Ionization-induced trapping of electrons in the density down-ramp is a way to trap and accelerate a large number of electrons, thus improving the efficiency of the laser-driven wakefield acceleration.

  10. Revising the Local Bubble Model due to Solar Wind Charge Exchange X-ray Emission

    Science.gov (United States)

    Shelton, Robin L.

    2009-03-01

    The hot Local Bubble surrounding the solar neighborhood has been primarily studied through observations of its soft X-ray emission. The measurements were obtained by attributing all of the observed local soft X-rays to the bubble. However, mounting evidence shows that the heliosphere also produces diffuse X-rays. The source is solar wind ions that have received an electron from another atom. The presence of this alternate explanation for locally produced diffuse X-rays calls into question the existence and character of the Local Bubble. This article addresses these questions. It reviews the literature on solar wind charge exchange (SWCX) X-ray production, finding that SWCX accounts for roughly half of the observed local 1/4 keV X-rays found at low latitudes. This article also makes predictions for the heliospheric O VI column density and intensity, finding them to be smaller than the observational error bars. Evidence for the continued belief that the Local Bubble contains hot gas includes the remaining local 1/4 keV intensity, the observed local O VI column density, and the need to fill the local region with some sort of plasma. If the true Local Bubble is half as bright as previously thought, then its electron density and thermal pressure are 1/sqrt{2} as great as previously thought, and its energy requirements and emission measure are 1/2 as great as previously thought. These adjustments can be accommodated easily, and, in fact, bring the Local Bubble’s pressure more in line with that of the adjacent material. Suggestions for future work are made.

  11. Accelerated inactivation of the L-type calcium current due to a mutation in CACNB2b underlies Brugada syndrome

    DEFF Research Database (Denmark)

    Cordeiro, Jonathan M; Marieb, Mark; Pfeiffer, Ryan

    2009-01-01

    S in which loss of function is caused by accelerated inactivation of I(Ca). The proband, a 32 year old male, displayed a Type I ST segment elevation in two right precordial ECG leads following a procainamide challenge. EP study was positive with induction of polymorphic VT/VF. Interrogation of implanted ICD...... significantly faster in mutant channels between 0 and + 20 mV. Action potential voltage clamp experiments showed that total charge was reduced by almost half compared to WT. We report the first BrS mutation in CaCNB2b resulting in accelerated inactivation of L-type calcium channel current. Our results suggest...

  12. Predictors of Local Recurrence Following Accelerated Partial Breast Irradiation: A Pooled Analysis

    International Nuclear Information System (INIS)

    Shah, Chirag; Wilkinson, John Ben; Lyden, Maureen; Beitsch, Peter; Vicini, Frank A.

    2012-01-01

    Purpose: To analyze a pooled set of nearly 2,000 patients treated on the American Society of Breast Surgeons (ASBS) Mammosite Registry Trial and at William Beaumont Hospital (WBH) to identify factors associated with local recurrence following accelerated partial breast irradiation (APBI). Methods and Materials: A total of 1,961 women underwent partial breast irradiation between April 1993 and November 2010 as part of the ASBS Registry Trial or at WBH. Rates of ipsilateral breast tumor recurrence (IBTR), regional recurrence (RR), distant metastases (DM), disease-free survival (DFS), cause-specific survival (CSS), and overall survival (OS) were analyzed for each group and for the pooled cohort. Clinical, pathologic, and treatment-related variables were analyzed including age, tumor stage/size, estrogen receptor status, surgical margins, and lymph node status to determine their association with IBTR. Results: The two groups weres similar, but WBH patients were more frequently node positive, had positive margins, and were less likely to be within the American Society for Radiation Oncology-unsuitable group. At 5 years, the rates of IBTR, RR, DM, DFS, CSS, and OS for the pooled group of patients were 2.9%, 0.5%, 2.4%, 89.1%, 98.5%, and 91.8%, respectively. The 5-year rate of true recurrence/marginal miss was 0.8%. Univariate analysis of IBTR found that negative estrogen receptor status (odds ratio [OR], 2.83, 95% confidence interval 1.55–5.13, p = 0.0007) was the only factor significantly associated with IBTR, while a trend was seen for age less than 50 (OR 1.80, 95% confidence interval 0.90–3.58, p = 0.10). Conclusions: Excellent 5-year outcomes were seen following APBI in over 1,900 patients. Estrogen receptor negativity was the only factor associated with IBTR, while a trend for age less than 50 was noted. Significant differences in factors associated with IBTR were noted between cohorts, suggesting that factors driving IBTR may be predicated based on the risk

  13. Turnaround radius in an accelerated universe with quasi-local mass

    Energy Technology Data Exchange (ETDEWEB)

    Faraoni, Valerio; Lapierre-Léonard, Marianne; Prain, Angus, E-mail: vfaraoni@ubishops.ca, E-mail: mlapierre12@ubishops.ca, E-mail: angusprain@gmail.com [Physics Department, Bishop' s University, 2600 College Street, Sherbrooke, Québec, J1M 1Z7 Canada (Canada)

    2015-10-01

    We apply the Hawking-Hayward quasi-local energy construct to obtain in a rigorous way the turnaround radius of cosmic structures in General Relativity. A splitting of this quasi-local mass into local and cosmological parts describes the interplay between local attraction and cosmological expansion.

  14. Turnaround radius in an accelerated universe with quasi-local mass

    International Nuclear Information System (INIS)

    Faraoni, Valerio; Lapierre-Léonard, Marianne; Prain, Angus

    2015-01-01

    We apply the Hawking-Hayward quasi-local energy construct to obtain in a rigorous way the turnaround radius of cosmic structures in General Relativity. A splitting of this quasi-local mass into local and cosmological parts describes the interplay between local attraction and cosmological expansion

  15. Presentation of a semiempirical method for the calculation of doses due to neutrons and capture gamma rays inside high energy accelerators rooms

    International Nuclear Information System (INIS)

    Larcher, A.M.; Bonet Duran, S.M.

    1998-01-01

    Full text: Medical electron accelerators operating above 10 MeV produce radiation beams that are contaminated with neutrons. Therefore, shielding design for high energy accelerator rooms must consider the neutron component of the radiation field. In this paper a semiempirical method is presented to calculate doses due to neutrons and capture gamma rays inside the room and the maze. The calculation method is based on the knowledge of the neutron yield Q (neutrons/Gy of photons at isocenter) and the average energy of the primary beam of neutrons Eo (MeV). The method constitutes an appropriate tool for shielding facilities evaluation. The accuracy of the method has been contrasted with data obtained from the literature and an excellent correlation among the calculations and the measured values was achieved. In addition, the method has been used in the verification of experimental data corresponding to a 15 MeV linear accelerator installed in the country with similar results. (author) [es

  16. Automatic enhancement of skin fluorescence localization due to refractive index matching

    Science.gov (United States)

    Churmakov, Dmitry Y.; Meglinski, Igor V.; Piletsky, Sergey A.; Greenhalgh, Douglas A.

    2004-07-01

    Fluorescence diagnostic techniques are notable amongst many other optical methods, as they offer high sensitivity and non-invasive measurements of tissue properties. However, a combination of multiple scattering and physical heterogeneity of biological tissues hampers the interpretation of the fluorescence measurements. The analyses of the spatial distribution of endogenous and exogenous fluorophores excitations within tissues and their contribution to the detected signal localization are essential for many applications. We have developed a novel Monte Carlo technique that gives a graphical perception of how the excitation and fluorescence detected signal are localized in tissues. Our model takes into account spatial distribution of fluorophores and their quantum yields. We demonstrate that matching of the refractive indices of ambient medium and topical skin layer improves spatial localization of the detected fluorescence signal within the tissue. This result is consistent with the recent conclusion that administering biocompatible agents results in higher image contrast.

  17. Local effects in thin elastic shell due to thermal and mechanical loadings

    International Nuclear Information System (INIS)

    Taheri, S.

    1987-01-01

    For a thick cylinder (1/15)<(h/rm)<(1/3) the local effect is represented by the same field. When the local effect is negligible the Love-Kirchhoff solution is valid for a thick cylinder. A shear effect shell theory may give for a thin cylinder a large error compared to the exact 3D solution on a thermal shock. The Love-Kirchhoff solution is generally not valid in the vicinity of a clamped or simply supported edge. A finite element program of thin shell with shear effect or thick shell ist not really reliable. A combination of 3D local solution and Love-Kirchhoff global solution through a transition zone may replace a complete 3D solution for not very thick structures. (orig./GL)

  18. Corrections to the apparent value of the cosmological constant due to local inhomogeneities

    International Nuclear Information System (INIS)

    Romano, Antonio Enea; Chen, Pisin

    2011-01-01

    Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the Universe can be accurately described by a homogeneous model. Even in the presence of a cosmological constant we cannot exclude nevertheless the presence of a small local inhomogeneity which could affect the apparent value of the cosmological constant. Neglecting the presence of the inhomogeneity can in fact introduce a systematic misinterpretation of cosmological data, leading to the distinction between an apparent and true value of the cosmological constant. We establish the theoretical framework to calculate the corrections to the apparent value of the cosmological constant by modeling the local inhomogeneity with a ΛLTB solution. Our assumption to be at the center of a spherically symmetric inhomogeneous matter distribution correspond to effectively calculate the monopole contribution of the large scale inhomogeneities surrounding us, which we expect to be the dominant one, because of other observations supporting a high level of isotropy of the Universe around us. By performing a local Taylor expansion we analyze the number of independent degrees of freedom which determine the local shape of the inhomogeneity, and consider the issue of central smoothness, showing how the same correction can correspond to different inhomogeneity profiles. Contrary to previous attempts to fit data using large void models our approach is quite general. The correction to the apparent value of the cosmological constant is in fact present for local inhomogeneities of any size, and should always be taken appropriately into account both theoretically and observationally

  19. Chronic Localized Back Pain Due to Posterior Cutaneous Nerve Entrapment Syndrome (POCNES): A New Diagnosis.

    Science.gov (United States)

    Boelens, Oliver B; Maatman, Robert C; Scheltinga, Marc R; van Laarhoven, Kees; Roumen, Rudi M

    2017-03-01

    Most patients with chronic back pain suffer from degenerative thoracolumbovertebral disease. However, the following case illustrates that a localized peripheral nerve entrapment must be considered in the differential diagnosis of chronic back pain. We report the case of a 26-year-old woman with continuous excruciating pain in the lower back area. Previous treatment for nephroptosis was to no avail. On physical examination the pain was present in a 2 x 2 cm area overlying the twelfth rib some 4 cm lateral to the spinal process. Somatosensory testing using swab and alcohol gauze demonstrated the presence of skin hypo- and dysesthesia over the painful area. Local pressure on this painful spot elicited an extreme pain response that did not irradiate towards the periphery. These findings were highly suggestive of a posterior version of the anterior cutaneous nerve entrapment syndrome (ACNES), a condition leading to a severe localized neuropathic pain in anterior portions of the abdominal wall. She demonstrated a beneficial albeit temporary response after lidocaine infiltration as dictated by an established diagnostic and treatment protocol for ACNES. She subsequently underwent a local neurectomy of the involved superficial branch of the intercostal nerve. This limited operation had a favorable outcome resulting in a pain-free return to normal activities up to this very day (follow-up of 24 months).We propose to name this novel syndrome "posterior cutaneous nerve entrapment syndrome" (POCNES). Each patient with chronic localized back pain should undergo simple somatosensory testing to detect the presence of overlying skin hypo- and dysesthesia possibly reflecting an entrapped posterior cutaneous nerve.Key words: Chronic pain, back pain, posterior cutaneous nerve entrapment, peripheral nerve entrapment, surgical treatment for pain, anterior cutaneous nerve entrapment.

  20. Renewable Energy, Climate Action and Resilient Societies: Accelerating the Global and Local Paradigm Shift

    International Nuclear Information System (INIS)

    Spencer, Thomas; Levai, David; Wang, Xin

    2017-07-01

    This report has been commissioned by a group of foundations in G20 countries, which have come together under the F20 platform in order to engage with the issue of climate change and sustainability in the context of the G20. The report analyzes the emerging energy transition towards efficient and renewable energy systems at global level and in specific G20 countries. On the basis of this analysis, and of the country specific case-studies that have also been conducted in the report, it provides recommendations for foundations and the G20 aimed at enhancing climate change mitigation and sustainability. Key Messages: 1. The global transition to renewable energy systems is underway and accelerating, driven by a combination of policy interventions, very rapid innovation, particularly the fall in renewable electricity costs, and changing societal priorities in many areas, such as the importance being placed on clean air, green industrial development, and investments in local communities. 2. This transition creates tremendous opportunities for countries and companies to ramp-up a new kind of job creation and economic development based on renewable, efficient energy systems. At the same time, countries and actors, who do not anticipate the shift, could be left behind and lose out economically. The good news is that the necessary tools are there. The main question is whether the social and political will for change can be developed and harnessed at the speed and scope required. 3. An economic shift on the scale and speed required to mitigate climate change cannot be achieved solely from the 'top-down'; it can only be implemented with the buy-in and participation of civil society. Worrying trends of inequality, economic disruption, and the fragmentation and fractiousness of public discourse make obtaining this social buy-in all the more difficult. Civil society must thus be seen as an essential partner of policies to drive a new paradigm of sustainable economic development

  1. Post- and interseismic deformation due to both localized and distributed creep at depth (Invited)

    Science.gov (United States)

    Hetland, E. A.; Zhang, G.; Hines, T.

    2013-12-01

    There are two end-member representations of the ductile lithosphere (i.e., the lower crust and uppermost mantle) commonly used in models of post- and interseismic deformation around strike-slip faults: either (1) laterally homogeneous ductile layers, with sharp contrasts in rheological properties between the layers, in which creep is distributed; or (2) discrete extensions of the fault at depth in which creep is fully localized. The most realistic representation of the ductile lithosphere on earthquake cycle time scales likely falls between these two end-members. Researchers have considered both distributed and localized creep when interpreting post- and interseismic deformation, although the two mechanisms are most commonly treated separately, with the localized creep often approximated by kinematic slip on planar faults. There are a few noteworthy models that considered the feedback between both distributed and localized creep, although those models were largely constrained to 2D geometries of infinite length faults. The thickness of shear zones in the ductile lithosphere may be comparable to the locking depth of the fault, and the existence of a deep shear zone does not preclude the possibility that some distributed creep occurs in the surrounding lithosphere. Furthermore, variations in rheology, including both rheological models and their parameters, may be more subtle than the discrete contrasts typically assumed. In this presentation, we consider models of postseismic deformation following a finite length, strike-slip fault, as well as models of interseismic deformation around an infinite length strike-slip fault. Both sets of models are capable of localized and distributed creep at depth, and use Maxwell viscoelasticity. We show that the horizontal surface velocities during the early postseismic period are most sensitive to the viscosity of the shear zone; however during much of the interseismic period the shear zone is not apparent from the surface

  2. Suppression of the reactive hyperemic response in the forearm due to local hand cooling.

    Science.gov (United States)

    Kilgour, R D; Carranza, A; Findlay, R

    1997-01-01

    Forearm blood flow (FBF) was measured by electrical impedance plethysmography in order to identify the influence of local cooling of the contralateral hand after 3 min of arterial occlusion. Ten volunteers (six females, four males) were randomly assigned to the following three experimental conditions on separate days: a) 6 min of local hand cooling (5-7 degrees C); b) 3 min of arterial occlusion of the forearm; and c) combined arterial occlusion and local cooling. All subjects experienced the typical pressor response during 6 min of hand cooling as evidenced by the significant increase (p forearm vascular resistance (FVR = MAP/FBF) made an initial drop during the first 30 s of cooling and then gradually rose to reach peak levels between 5-6 min of cooling. With respect to the hyperemic response, FBF significantly increased (p cooling, FBF increased above baseline values and reached peak levels during the initial 30 s of the post-occlusion period. However, the magnitude of the hyperemic response was significantly lower in the cold condition compared to the hyperemia alone (3.20 +/- 0.42 vs 6.75 +/- 0.64 ml x 100 ml-1.min-1; p cooling had an overriding effect on the factors that promote peripheral vasodilation following brief periods (3 min) of arterial occlusion.

  3. Entropy Generation Due to Natural Convection in a Partially Heated Cavity by Local RBF-DQ Method

    DEFF Research Database (Denmark)

    Soleimani, S.; Qajarjazi, A.; Bararnia, H.

    2011-01-01

    The Local Radial Basis Function-Differential Quadrature (RBF-DQ) method is applied to twodimensional incompressible Navier-Stokes equations in primitive form. Numerical results of heatlines and entropy generation due to heat transfer and fluid friction have been obtained for laminar natural...

  4. Small-sized linear accelerator of 2.5 MeV electrons with a local radiation shield for custom examination of freight transported by motor transport

    International Nuclear Information System (INIS)

    Baklanov, A.V.; Gavrish, Yu.N.; Klinov, A.P.; Krest'yaninov, A.S.; Nikolaev, V.M.; Fomin, L.P.; Linkenbach, H.A.; Geus, G.; Knospel, W.

    2001-01-01

    A new development of a small-sized linear accelerator of 2.5 MeV electrons with a local radiation protection is described. The accelerator is intended for movable facilities of radiation custom of the freight transported by motor transport. Main constructive solutions, mass and dimension characteristics and results of preliminary tests of the accelerator parameters and characteristics of radiation protection are presented [ru

  5. On the impact of topography and building mask on time varying gravity due to local hydrology

    Science.gov (United States)

    Deville, S.; Jacob, T.; Chéry, J.; Champollion, C.

    2013-01-01

    We use 3 yr of surface absolute gravity measurements at three sites on the Larzac plateau (France) to quantify the changes induced by topography and the building on gravity time-series, with respect to an idealized infinite slab approximation. Indeed, local topography and buildings housing ground-based gravity measurement have an effect on the distribution of water storage changes, therefore affecting the associated gravity signal. We first calculate the effects of surrounding topography and building dimensions on the gravity attraction for a uniform layer of water. We show that a gravimetric interpretation of water storage change using an infinite slab, the so-called Bouguer approximation, is generally not suitable. We propose to split the time varying gravity signal in two parts (1) a surface component including topographic and building effects (2) a deep component associated to underground water transfer. A reservoir modelling scheme is herein presented to remove the local site effects and to invert for the effective hydrological properties of the unsaturated zone. We show that effective time constants associated to water transfer vary greatly from site to site. We propose that our modelling scheme can be used to correct for the local site effects on gravity at any site presenting a departure from a flat topography. Depending on sites, the corrected signal can exceed measured values by 5-15 μGal, corresponding to 120-380 mm of water using the Bouguer slab formula. Our approach only requires the knowledge of daily precipitation corrected for evapotranspiration. Therefore, it can be a useful tool to correct any kind of gravimetric time-series data.

  6. Cache Locality-Centric Parallel String Matching on Many-Core Accelerator Chips

    OpenAIRE

    Tran, Nhat-Phuong; Lee, Myungho; Choi, Dong Hoon

    2015-01-01

    Aho-Corasick (AC) algorithm is a multiple patterns string matching algorithm commonly used in computer and network security and bioinformatics, among many others. In order to meet the highly demanding computational requirements imposed on these applications, achieving high performance for the AC algorithm is crucial. In this paper, we present a high performance parallelization of the AC on the many-core accelerator chips such as the Graphic Processing Unit (GPU) from Nvidia and...

  7. Local pressure gradients due to incipience of boiling in subcooled flows

    Energy Technology Data Exchange (ETDEWEB)

    Ruggles, A.E.; McDuffee, J.L. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-09-01

    Models for vapor bubble behavior and nucleation site density during subcooled boiling are integrated with boundary layer theory in order to predict the local pressure gradient and heat transfer coefficient. Models for bubble growth rate and bubble departure diameter are used to scale the movement of displaced liquid in the laminar sublayer. An added shear stress, analogous to a turbulent shear stress, is derived by considering the liquid movement normal to the heated surface. The resulting mechanistic model has plausible functional dependence on wall superheat, mass flow, and heat flux and agrees well with data available in the literature.

  8. Finite-volume effects due to spatially non-local operators arXiv

    CERN Document Server

    Briceño, Raúl A.; Hansen, Maxwell T.; Monahan, Christopher J.

    Spatially non-local matrix elements are useful lattice-QCD observables in a variety of contexts, for example in determining hadron structure. To quote credible estimates of the systematic uncertainties in these calculations, one must understand, among other things, the size of the finite-volume effects when such matrix elements are extracted from numerical lattice calculations. In this work, we estimate finite-volume effects for matrix elements of non-local operators, composed of two currents displaced in a spatial direction by a distance $\\xi$. We find that the finite-volume corrections depend on the details of the matrix element. If the external state is the lightest degree of freedom in the theory, e.g.~the pion in QCD, then the volume corrections scale as $ e^{-m_\\pi (L- \\xi)} $, where $m_\\pi$ is the mass of the light state. For heavier external states the usual $e^{- m_\\pi L}$ form is recovered, but with a polynomial prefactor of the form $L^m/|L - \\xi|^n$ that can lead to enhanced volume effects. These ...

  9. Occupational doses due to photoneutrons in medical linear accelerators rooms; Doses ocupacionais devido a neutrons em salas de aceleradores lineares de uso medico

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Alessandro Facure Neves de Salles

    2006-04-15

    Medical linear accelerators, with maximum photon energies above 10 MeV, are becoming of common use in Brazil. Although desirable in the therapeutic point of view, the increase in photon energies causes the generation of undesired neutrons, which are produced through nuclear reactions between photons and the high Z target nuclei of the materials that constitute the accelerator head. In this work, MCNP simulation was undertaken to examine the neutron equivalent doses around the accelerators head and at the entrance of medical linear accelerators treatment rooms, some of them licensed in Brazil by the National Regulatory Agency (CNEN). The simulated neutron dose equivalents varied between 2 e 26 {mu} Sv/Gy{sub RX}, and the results were compared with calculations performed with the use of some semi-empirical equations found in literature. It was found that the semi-empirical equations underestimate the simulated neutron doses in the majority of the cases, if compared to the simulated values, suggesting that these equations must be revised, due to the increasing number of high energy machines in the country. (author)

  10. Magnetic Doppler imaging considering atmospheric structure modifications due to local abundances: a luxury or a necessity?

    Science.gov (United States)

    Kochukhov, O.; Wade, G. A.; Shulyak, D.

    2012-04-01

    Magnetic Doppler imaging is currently the most powerful method of interpreting high-resolution spectropolarimetric observations of stars. This technique has provided the very first maps of stellar magnetic field topologies reconstructed from time series of full Stokes vector spectra, revealing the presence of small-scale magnetic fields on the surfaces of Ap stars. These studies were recently criticised by Stift et al., who claimed that magnetic inversions are not robust and are seriously undermined by neglecting a feedback on the Stokes line profiles from the local atmospheric structure in the regions of enhanced metal abundance. We show that Stift et al. misinterpreted published magnetic Doppler imaging results and consistently neglected some of the most fundamental principles behind magnetic mapping. Using state-of-the-art opacity sampling model atmosphere and polarized radiative transfer codes, we demonstrate that the variation of atmospheric structure across the surface of a star with chemical spots affects the local continuum intensity but is negligible for the normalized local Stokes profiles except for the rare situation of a very strong line in an extremely Fe-rich atmosphere. For the disc-integrated spectra of an Ap star with extreme abundance variations, we find that the assumption of a mean model atmosphere leads to moderate errors in Stokes I but is negligible for the circular and linear polarization spectra. Employing a new magnetic inversion code, which incorporates the horizontal variation of atmospheric structure induced by chemical spots, we reconstructed new maps of magnetic field and Fe abundance for the bright Ap star α2 CVn. The resulting distribution of chemical spots changes insignificantly compared to the previous modelling based on a single model atmosphere, while the magnetic field geometry does not change at all. This shows that the assertions by Stift et al. are exaggerated as a consequence of unreasonable assumptions and

  11. Perturbation of the energy loss spectra for an accelerated electron beam due to the photo injector exit

    CERN Document Server

    Salah, W

    2003-01-01

    The influence of the photo-injector exit hall on the energy loss for an accelerated electron beam is investigated, by calculating the total energy transferred from the electrons to the wakefields, which are driven by the beam. The obtained energy loss is compared to those previously obtained for a 'pill-box' cavity. This comparison shows that the influence of this hall, in terms of energy loss, varies over the beam length. It is strongest in the middle of the beam and decreases towards both ends. In consequence of this perturbation, the center of the beam is displaced from its initial position during the first phase (t < 200 ps) where the exit aperture has no effect to a new equilibrium position which takes place at 200 < t < 250 ps. (author)

  12. Enhancement of conductivity due to local disorder in a one-dimensional conductor

    International Nuclear Information System (INIS)

    Morifuji, Masato; Maeda, Yusuke

    2011-01-01

    We theoretically investigate electron transport in a one-dimensional conductor with a locally disordered potential by using the non-equilibrium Green’s function theory. It is found that, by changing the energy of a site in a one-dimensional atomic chain, the electron conductivity can be larger when the modulated site energy is smaller than that of the other sites. This contradicts the conventional picture that an electron is scattered by the disorder of the potential, because such a scattering process usually causes resistivity. We show that the enhancement of conductivity that seems contradictory to the conventional picture of electron motion is explained by the change of energy of quasi bound states in the conductor. (paper)

  13. A localized outbreak of cholera due to vibrio cholerae, ogawa resistant to tetracyclines

    International Nuclear Information System (INIS)

    Ahmed, S.

    2015-01-01

    To study the clinical and laboratory parameters of a localized Cholera outbreak and determine the sensitivity pattern of the subtype involved. Study Design: A descriptive study. Place and Duration of Study: Combined Military Hospital, Lahore. Duration of Study: Two weeks. Patients and Methods: The study is about a localized outbreak of cholera in a group of soldiers, who consumed water from a single contaminated source of water. We are presenting here an account of the clinical and laboratory parameters of 39 hospitalized cases of cholera, who presented with profuse watery diarrhoea and vomiting. There vital signs, hydration status and systemic examination findings were recorded. Stool samples were sent for routine and microscopic examination and bacteriological culture. Blood samples were taken for complete blood count, serum sodium, potassium, urea and creatinine examination. SPSS 18 was used for statistical analysis of the results. Results: The average age of thirty nine men studied in this outbreak was 24.9 ± 6.9 years. There was no statistically significant difference between confirmed and suspected cholera cases on descriptive analysis of the clinical and laboratory parameters. Majority of patients showed pre-renal azotemia which improved within 48 to 72 hours of hospitalization. Stool cultures isolated Vibrio cholerae, subtype Ogawa, which was resistant to tetracyclines, cotrimoxazole and nalidixic acid but sensitive to fluoroquinolones and third generation cephalosporins. The outbreak was controlled when the contaminated water source was sealed and rectified. Conclusion: Multiple drug resistance strains of Vibrio cholera are causing large outbreaks which should be controlled by prevention of the disease and avoiding inappropriate use of antibiotics. (author)

  14. Inhibition of Direct Electrolytic Ammonia Oxidation Due to a Change in Local pH

    International Nuclear Information System (INIS)

    Zöllig, Hanspeter; Morgenroth, Eberhard; Udert, Kai M.

    2015-01-01

    Electrochemical ammonia oxidation has gained a lot of attention recently as an efficient method for ammonia removal from wastewater, for the use in ammonia-based fuel cells and the production of high purity hydrogen. Thermally decomposed iridium oxide films (TDIROF) have been shown to be catalytically active for direct ammonia oxidation in aqueous solutions if NH 3 is present. However, the process was reported to be rapidly inhibited on TDIROF. Herein, we show that this fast inhibition of direct ammonia oxidation does not result from surface poisoning by adsorbed elemental nitrogen (N ads ). Instead, we propose that direct ammonia oxidation and oxygen evolution can lead to a drop of the local pH at the electrode resulting in a low availability of the actual reactant, NH 3 . The hypothesis was tested with cyclic voltammetry (CV) experiments on stagnant and rotating disk electrodes (RDE). The CV experiments on the stagnant electrode revealed that the decrease of the ammonia oxidation peaks was considerably reduced by introducing an idle phase at open circuit potential between subsequent scans. Furthermore, the polarization of the TDIROF electrode into the hydrogen evolution region (HER) resulted in increased ammonia oxidation peaks in the following anodic scans which can be explained with an increased local pH after the consumption of protons in the HER. On the RDE, the ammonia oxidation peaks did not decrease in immediately consecutive scans. These findings would not be expected if surface poisoning was responsible for the fast inhibition but they are in good agreement with the proposed mechanism of pH induced limitation by the reactant, NH 3 . The plausibility of the mechanism was also supported by our numerical simulations of the processes in the Nernstian diffusion layer. The knowledge about this inhibition mechanism of direct ammonia oxidation is especially important for the design of electrochemical cells for wastewater treatment. The mechanism is not only

  15. Intrinsic spatial resolution limitations due to differences between positron emission position and annihilation detection localization

    International Nuclear Information System (INIS)

    Perez, Pedro; Malano, Francisco; Valente, Mauro

    2012-01-01

    Since its successful implementation for clinical diagnostic, positron emission tomography (PET) represents the most promising medical imaging technique. The recent major growth of PET imaging is mainly due to its ability to trace the biologic pathways of different compounds in the patient's body, assuming the patient can be labeled with some PET isotope. Regardless of the type of isotope, the PET imaging method is based on the detection of two 511-keV gamma photons being emitted in opposite directions, with almost 180 deg between them, as a consequence of electron-positron annihilation. Therefore, this imaging method is intrinsically limited by random uncertainties in spatial resolutions, related with differences between the actual position of positron emission and the location of the detected annihilation. This study presents an approach with the Monte Carlo method to analyze the influence of this effect on different isotopes of potential implementation in PET. (author)

  16. Conductance maps of quantum rings due to a local potential perturbation.

    Science.gov (United States)

    Petrović, M D; Peeters, F M; Chaves, A; Farias, G A

    2013-12-11

    We performed a numerical simulation of the dynamics of a Gaussian shaped wavepacket inside a small sized quantum ring, smoothly connected to two leads and exposed to a perturbing potential of a biased atomic force microscope tip. Using the Landauer formalism, we calculated conductance maps of this system in the case of single and two subband transport. We explain the main features in the conductance maps as due to the AFM tip influence on the wavepacket phase and amplitude. In the presence of an external magnetic field, the tip modifies the ϕ0 periodic Aharonov-Bohm oscillation pattern into a ϕ0/2 periodic Al'tshuler-Aronov-Spivak oscillation pattern. Our results in the case of multiband transport suggest tip selectivity to higher subbands, making them more observable in the total conductance map.

  17. Ectopic ACTH secretion due to a bronchopulmonary carcinoid localized by somatostatin receptor scintigraphy.

    Science.gov (United States)

    Iser, G; Pfohl, M; Dörr, U; Weiss, E M; Seif, F J

    1994-11-01

    We present the case of a 65-year-old woman with an adrenocorticotropic hormone (ACTH) secreting bronchopulmonary carcinoid. This patient showed the typical long history of Cushing's syndrome, including hypokaliemia, impaired glucose tolerance, high levels of ACTH and beta-endorphin, and coproduction of other peptides. At the onset of clinical symptoms in 1979 an adrenal adenoma was suspected, and left-sided adrenalectomy was performed. The symptoms soon recurred, and the diagnosis of ACTH-dependent Cushing's syndrome was made. As no ACTH-secreting tumor was found, the right adrenal was resected, and the patient was followed up regularly. Fourteen years later chest roentgenography and computed tomography revealed a para-aortic pulmonary lesion, which was suspicious for a bronchopulmonary carcinoid. ACTH and beta-endorphin were excessively, pancreatic polypeptide slightly elevated at that time. The final diagnosis was made using somatostatin receptor scintigraphy which confirmed the hormonal activity of the suspicious lesion; no additional focus was found. This method turned out to be not only a useful additional localization technique but also a promising tool for characterization and staging of a suspected ACTH-producing carcinoid. The tumor was resected curatively, and the diagnosis was confirmed histologically.

  18. Expression of S100A6 in Rat Hippocampus after Traumatic Brain Injury Due to Lateral Head Acceleration

    Directory of Open Access Journals (Sweden)

    Bo Fang

    2014-04-01

    Full Text Available In a rat model of traumatic brain injury (TBI, we investigated changes in cognitive function and S100A6 expression in the hippocampus. TBI-associated changes in this protein have not previously been reported. Rat S100A6 was studied via immunohistochemical staining, Western blot, and reverse transcription-polymerase chain reaction (RT-PCR after either lateral head acceleration or sham. Reduced levels of S100A6 protein and mRNA were observed 1 h after TBI, followed by gradual increases over 6, 12, 24, and 72 h, and then a return to sham level at 14 day. Morris water maze (MWM test was used to evaluate animal spatial cognition. TBI- and sham-rats showed an apparent learning curve, expressed as escape latency. Although TBI-rats displayed a relatively poorer cognitive ability than sham-rats, the disparity was not significant early post-injury. Marked cognitive deficits in TBI-rats were observed at 72 h post-injury compared with sham animals. TBI-rats showed decreased times in platform crossing in the daily MWM test; the performance at 72 h post-injury was the worst. In conclusion, a reduction in S100A6 may be one of the early events that lead to secondary cognitive decline after TBI, and its subsequent elevation is tightly linked with cognitive improvement. S100A6 may play important roles in neuronal degeneration and regeneration in TBI.

  19. Estimated characteristics modification of silicon detectors due to their use at the LHC-accelerator and in AMS space conditions

    International Nuclear Information System (INIS)

    Lazanu, I.; Lazanu, S.

    2003-01-01

    In this talk, the phenomenological model developed by the authors in previous papers has been used to evaluate the degradation induced in high resistivity silicon detectors by pion and proton irradiation at the future accelerator facilities or by cosmic protons considering the continuous irradiation for ten years of work. The equations governing the degradation of the lattice are explicitly considered. The damage has been analysed at the microscopic level (defects production and their evolution toward equilibrium) and at the macroscopic level (only the changes in the leakage current of the p-n junction was considered). The rates of production of primary defects, as well as their evolution toward equilibrium have been evaluated considering explicitly irradiation field of the specified applications, by the type of the projectile particle and its energy. The influence of these defects on the leakage current density has been compared with experimental data from the literature, and predictions for the LHC radiation fields, as well as for space missions in the near Earth orbits have been done, in the frame of the Schokley-Read-Hall model. (authors)

  20. A study on the flow field and local heat transfer performance due to geometric scaling of centrifugal fans

    International Nuclear Information System (INIS)

    Stafford, Jason; Walsh, Ed; Egan, Vanessa

    2011-01-01

    Highlights: ► Velocity field and local heat transfer trends of centrifugal fans. ► Time-averaged vortices are generated by flow separation. ► Local vortex and impingement regions are evident on surface heat transfer maps. ► Miniature centrifugal fans should be designed with an aspect ratio below 0.3. ► Theory under predicts heat transfer due to complex, unsteady outlet flow. - Abstract: Scaled versions of fan designs are often chosen to address thermal management issues in space constrained applications. Using velocity field and local heat transfer measurement techniques, the thermal performance characteristics of a range of geometrically scaled centrifugal fan designs have been investigated. Complex fluid flow structures and surface heat transfer trends due to centrifugal fans were found to be common over a wide range of fan aspect ratios (blade height to fan diameter). The limiting aspect ratio for heat transfer enhancement was 0.3, as larger aspect ratios were shown to result in a reduction in overall thermal performance. Over the range of fans examined, the low profile centrifugal designs produced significant enhancement in thermal performance when compared to that predicted using classical laminar flow theory. The limiting non-dimensional distance from the fan, where this enhancement is no longer apparent, has also been determined. Using the fundamental information inferred from local velocity field and heat transfer measurements, selection criteria can be determined for both low and high power practical applications where space restrictions exist.

  1. Low-level laser therapy (LLLT) accelerates the sternomastoid muscle regeneration process after myonecrosis due to bupivacaine.

    Science.gov (United States)

    Alessi Pissulin, Cristiane Neves; Henrique Fernandes, Ana Angélica; Sanchez Orellana, Alejandro Manuel; Rossi E Silva, Renata Calciolari; Michelin Matheus, Selma Maria

    2017-03-01

    Because of its long-lasting analgesic action, bupivacaine is an anesthetic used for peripheral nerve block and relief of postoperative pain. Muscle degeneration and neurotoxicity are its main limitations. There is strong evidence that low-level laser therapy (LLLT) assists in muscle and nerve repair. The authors evaluated the effects of a Gallium Arsenide laser (GaAs), on the regeneration of muscle fibers of the sternomastoid muscle and accessory nerve after injection of bupivacaine. In total, 30 Wistar adult rats were divided into 2 groups: control group (C: n=15) and laser group (L: n=15). The groups were subdivided by antimere, with 0.5% bupivacaine injected on the right and 0.9% sodium chloride on the left. LLLT (GaAs 904nm, 0,05W, 2.8J per point) was administered for 5 consecutive days, starting 24h after injection of the solutions. Seven days after the trial period, blood samples were collected for determination of creatine kinase (CK). The sternomastoid nerve was removed for morphological and morphometric analyses; the surface portion of the sternomastoid muscle was used for histopathological and ultrastructural analyses. Muscle CK and TNFα protein levels were measured. The anesthetic promoted myonecrosis and increased muscle CK without neurotoxic effects. The LLLT reduced myonecrosis, characterized by a decrease in muscle CK levels, inflammation, necrosis, and atrophy, as well as the number of central nuclei in the muscle fibers and the percentage of collagen. TNFα values remained constant. LLLT, at the dose used, reduced fibrosis and myonecrosis in the sternomastoid muscle triggered by bupivacaine, accelerating the muscle regeneration process. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. internal radiation dose assessment due to ionizing radio contaminants in some local foodstuffs

    International Nuclear Information System (INIS)

    AbdElKader, F.M.

    1996-01-01

    Over the last 30 years, radioactivity has been monitored in foodstuffs in Egypt. The present work deals with the radioactivity monitored during two years (1990 - 1992) at eight major Egyptian governorates. Sampled food items were selected to cover most foodstuffs eaten by egyptian population according to their habits. The daily food consumption by egyptian population and the constituents of such consumption were estimated according to published international data and knowledge of the different feeding habits of the egyptians. About 1200 samples were collected from the markets of the main city of each governorate and prepared for counting according to the egyptian kitchen habits. The counting systems used in determination and indentification of radionuclides were : a 3 inch HPGe detector attached to 800 channel MCA and PC and a 3 inch phoswich detector attached to an anticoincidence circuit for low beta / gamma counting. The gamma spectroscopy system was calibrated using isotopic solution mixture while the low beta counting system was calibrated using H CI. Counting time for the first system was 20 - 72 hours and for the second system was half to one hour. The main radionuclides identified in foodstuffs were Cs - 137 and K - 40 . The radioactivity concentration of Cs - 137 was found to be in the range between 1.0 Bq / Kg for macaroni and 3.5 Bq / Kg for nile beans. The K - 40 concentration range between 19 Bq / Kg for macaroni to 363 Bq / Kg for nile beans. The population weighted values in case of Cs - 137 was found as 3.56 Bq /d and for K - 40 was 188 Bq /d. The resulted effective dose due to food intake was found be 16 . 4 U Sv /a for Cs-137 and 354 μSv / a for K -40 . This value for Cs - 137 is found in the exemption limit while that of K -40 is twice the published value. This may depend on the egyptian feeding habit which depends mainly on wheat (bread) and nile beans which are very rich in potassium.The resulted collective dose was found to be : 21323 person

  3. READING, PREPROCESSING OF ACCELERATIONS AND CORNERS INCLINATION WITH MPU-6050 I RECORD THEM ON SD-CARD THE ARDUINO DUE

    Directory of Open Access Journals (Sweden)

    V. G. Mikhailov

    2016-01-01

    Full Text Available The short review of microcontrollers of family Arduino, their characteristics and application fields is given. Importance of record of parameters of researched object is marked to produce debugging of control systems on microcontrollers Arduino. Unique possibility of registration of parameters in family Arduino is record on SD a card in an alpha mode with usage of functions print (, write (. The problems connected to record of the binary data on SD a card on microcontroller Arduino Due are considered. The analysis of methods of record of the binary data on SD-card Arduino Due, originating problems with neocleaning of memory from the previous program leading to possibility of duplication of the data on SD to a card, presence of the erratic point of view about restriction of volumes of data record and necessity of usage become outdated SD-cards is carried out. Ways of elimination of the marked lacks are considered. The estimation of high-speed performance of various approaches of a data recording on SD a card is led. On the basis of the led researches the approach of multiplexing of the writeable information at the expense of conversion of the binary data is offered is byte-serial in a character array in code ASCI without magnification of their volume and record by units on 240 byte. It allows to use as much as possible standard function possibilities write ( Arduino and specificity of the organization of memory SD of cards and to increase high-speed performance more than in 1100 times in comparison with record in a character type on one byte.It is marked that usage of decisions of an exception of duplication of the data offered at forums does not provide completeness of their elimination. For Arduino Due for storage cleaning it is necessary usages of the special programmator or setting of the new program of loading.

  4. Ordinary mode reflectometry. Modification of the scattering and cut-off responses due to the shape of localized density fluctuations

    International Nuclear Information System (INIS)

    Fanack, C.; Boucher, I.; Heuraux, S.; Leclert, G.; Clairet, F.; Zou, X.L.

    1996-01-01

    Ordinary wave reflectometry in a plasma containing a localized density perturbation is studied with a 1-D model. The phase response is studied as a function of the wavenumber and position of the perturbation. It is shown that it strongly depends upon the perturbation shape and size. For a small perturbation wavenumber, the response is due to the oscillation of the cut-off layer. For larger wavenumbers, two regimes are found: for a broad perturbation, the phase response is an image of the perturbation itself; for a narrow perturbation, it is rather an image of the Fourier transform. For tokamak plasmas it turns out that, for the fluctuation spectra usually observed, the phase response comes primarily from those fluctuations that are localized at the cut-off. Results of a 2-D numerical model show that geometry effects are negligible for the scattering by radial fluctuations. (author)

  5. Vanishing Clams on an Iberian Beach: Local Consequences and Global Implications of Accelerating Loss of Shells to Tourism

    Science.gov (United States)

    Kowalewski, Michał; Domènech, Rosa; Martinell, Jordi

    2014-01-01

    Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978–1981 and 2008–2010) in one small embayment on the Mediterranean coast of the Iberian Peninsula. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. During the same time interval the abundance of mollusk shells along the shoreline decreased by a comparable factor (2.62) and was significantly and negatively correlated with tourist arrivals (r = −0.52). The strength of the correlation increased when data were restricted to months with high tourist arrivals (r = −0.72). In contrast, the maximum monthly wave energy (an indirect proxy for changes in rate of onshore shell transport) was not significantly correlated with shell abundance (r = 0.10). Similarly, rank dominance of common species, drilling predation intensity, and body size-frequency distribution patterns have all remained stable over recent decades. A four-fold increase in global tourist arrivals over the last 30 years may have induced a comparable worldwide acceleration in shell removal from marine shorelines, resulting in multiple, currently unquantifiable, habitat changes such as increased beach erosion, changes in calcium carbonate recycling, and declines in diversity and abundance of organisms, which are dependent on shell availability. PMID:24421895

  6. Vanishing clams on an Iberian beach: local consequences and global implications of accelerating loss of shells to tourism.

    Science.gov (United States)

    Kowalewski, Michał; Domènech, Rosa; Martinell, Jordi

    2014-01-01

    Multi-decadal increase in shell removal by tourists, a process that may accelerate degradation of natural habitats, was quantified via two series of monthly surveys, conducted thirty years apart (1978-1981 and 2008-2010) in one small embayment on the Mediterranean coast of the Iberian Peninsula. Over the last three decades, the local tourist arrivals have increased almost three-fold (2.74), while the area has remained unaffected by urban encroachment and commercial fisheries. During the same time interval the abundance of mollusk shells along the shoreline decreased by a comparable factor (2.62) and was significantly and negatively correlated with tourist arrivals (r = -0.52). The strength of the correlation increased when data were restricted to months with high tourist arrivals (r = -0.72). In contrast, the maximum monthly wave energy (an indirect proxy for changes in rate of onshore shell transport) was not significantly correlated with shell abundance (r = 0.10). Similarly, rank dominance of common species, drilling predation intensity, and body size-frequency distribution patterns have all remained stable over recent decades. A four-fold increase in global tourist arrivals over the last 30 years may have induced a comparable worldwide acceleration in shell removal from marine shorelines, resulting in multiple, currently unquantifiable, habitat changes such as increased beach erosion, changes in calcium carbonate recycling, and declines in diversity and abundance of organisms, which are dependent on shell availability.

  7. A study on the flow field and local heat transfer performance due to geometric scaling of centrifugal fans

    Energy Technology Data Exchange (ETDEWEB)

    Stafford, Jason, E-mail: jason.stafford@ul.ie [Stokes Institute, Mechanical, Aeronautical and Biomedical Engineering Department, University of Limerick, Limerick (Ireland); Walsh, Ed; Egan, Vanessa [Stokes Institute, Mechanical, Aeronautical and Biomedical Engineering Department, University of Limerick, Limerick (Ireland)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Velocity field and local heat transfer trends of centrifugal fans. Black-Right-Pointing-Pointer Time-averaged vortices are generated by flow separation. Black-Right-Pointing-Pointer Local vortex and impingement regions are evident on surface heat transfer maps. Black-Right-Pointing-Pointer Miniature centrifugal fans should be designed with an aspect ratio below 0.3. Black-Right-Pointing-Pointer Theory under predicts heat transfer due to complex, unsteady outlet flow. - Abstract: Scaled versions of fan designs are often chosen to address thermal management issues in space constrained applications. Using velocity field and local heat transfer measurement techniques, the thermal performance characteristics of a range of geometrically scaled centrifugal fan designs have been investigated. Complex fluid flow structures and surface heat transfer trends due to centrifugal fans were found to be common over a wide range of fan aspect ratios (blade height to fan diameter). The limiting aspect ratio for heat transfer enhancement was 0.3, as larger aspect ratios were shown to result in a reduction in overall thermal performance. Over the range of fans examined, the low profile centrifugal designs produced significant enhancement in thermal performance when compared to that predicted using classical laminar flow theory. The limiting non-dimensional distance from the fan, where this enhancement is no longer apparent, has also been determined. Using the fundamental information inferred from local velocity field and heat transfer measurements, selection criteria can be determined for both low and high power practical applications where space restrictions exist.

  8. Local heart irradiation of ApoE−/− mice induces microvascular and endocardial damage and accelerates coronary atherosclerosis

    International Nuclear Information System (INIS)

    Gabriels, Karen; Hoving, Saske; Seemann, Ingar; Visser, Nils L.; Gijbels, Marion J.; Pol, Jeffrey F.; Daemen, Mat J.; Stewart, Fiona A.; Heeneman, Sylvia

    2012-01-01

    Background and purpose: Radiotherapy of thoracic and chest-wall tumors increases the long-term risk of radiation-induced heart disease, like a myocardial infarct. Cancer patients commonly have additional risk factors for cardiovascular disease, such as hypercholesterolemia. The goal of this study is to define the interaction of irradiation with such cardiovascular risk factors in radiation-induced damage to the heart and coronary arteries. Material and methods: Hypercholesterolemic and atherosclerosis-prone ApoE −/− mice received local heart irradiation with a single dose of 0, 2, 8 or 16 Gy. Histopathological changes, microvascular damage and functional alterations were assessed after 20 and 40 weeks. Results: Inflammatory cells were significantly increased in the left ventricular myocardium at 20 and 40 weeks after 8 and 16 Gy. Microvascular density decreased at both follow-up time-points after 8 and 16 Gy. Remaining vessels had decreased alkaline phosphatase activity (2–16 Gy) and increased von Willebrand Factor expression (16 Gy), indicative of endothelial cell damage. The endocardium was extensively damaged after 16 Gy, with foam cell accumulations at 20 weeks, and fibrosis and protein leakage at 40 weeks. Despite an accelerated coronary atherosclerotic lesion development at 20 weeks after 16 Gy, gated SPECT and ultrasound measurements showed only minor changes in functional cardiac parameters at 20 weeks. Conclusions: The combination of hypercholesterolemia and local cardiac irradiation induced an inflammatory response, microvascular and endocardial damage, and accelerated the development of coronary atherosclerosis. Despite these pronounced effects, cardiac function of ApoE −/− mice was maintained.

  9. On waves below the local proton gyrofrequency in auroral acceleration regions

    International Nuclear Information System (INIS)

    Gustafsson, G.; Andre, M.; Matson, L.; Koskinen, H.

    1990-01-01

    The Viking wave electric field and density fluctuation measurements together with simultaneous particle observations are used to study waves at frequencies below the local proton gyrofrequency. Such waves were observed during about 20% of nightside auroral field line crossings by Viking at altitudes between 2,000 and 10,000 km. The observations are different from earlier spacecraft observations of similar waves in such a way that the center frequency in about one out of four of the observed events was below the gyrofrequency of singly charged helium, which has not been reported previously. The waves were well correlated with precipitating electrons of energies of a few keV and with VLF auroral hiss. Detailed investigations of simultaneously observed wave emissions, particles, and total densities strongly suggest that secondary peaks at keV energies in the distributions of downgoing electrons can cause the emissions

  10. Treatment of two postoperative endophthalmitis cases due to Aspergillus flavus and Scopulariopsis spp. with local and systemic antifungal therapy

    Directory of Open Access Journals (Sweden)

    Uyar Guliz

    2007-07-01

    Full Text Available Abstract Background Endophthalmitis is the inflammatory response to invasion of the eye with bacteria or fungi. The incidence of endophthalmitis after cataract surgery varies between 0.072–0.13 percent. Treatment of endophthalmitis with fungal etiology is difficult. Case Presentation Case 1: A 71-year old male diabetic patient developed postoperative endophthalmitis due to Aspergillus flavus. The patient was treated with topical amphotericin B ophthalmic solution, intravenous (IV liposomal amphotericin-B and caspofungin following vitrectomy. Case 2: A 72-year old male cachectic patient developed postoperative endophthalmitis due to Scopulariopsis spp. The patient was treated with topical and IV voriconazole and caspofungin. Conclusion Aspergillus spp. are responsible of postoperative fungal endophthalmitis. Endophthalmitis caused by Scopulariopsis spp. is a very rare condition. The two cases were successfully treated with local and systemic antifungal therapy.

  11. A pilot study of accelerated superfractionated radiotherapy for locally advanced cancer of the uterine cervix

    Energy Technology Data Exchange (ETDEWEB)

    Gieschen, H; Kavanagh, B; Kaufman, N; West, R; Goplerud, D; Schmidt-Ullrich, R

    1995-07-01

    Purpose: Retrospective studies have suggested that overall treatment time is an important determinant of outcome for locally advanced squamous carcinoma of the cervix managed with definitive radiotherapy. We initiated a prospective clinical trial to test the hypothesis that minimizing treatment time can prevent tumor cell repopulation in squamous cell carcinoma of the cervix. Materials and Methods: Between 1989 and 1994 twenty two patients with FIGO stage IIIA to IVA squamous cell carcinoma of the cervix were treated as follows: Forty-five Gy was delivered to the whole pelvis in 25 fractions in 5 weeks using photon energies of 6 MV or greater. On Monday, Wednesday, and Friday of each of the last three weeks of treatment, a boost treatment of 1.6 Gy was given via small lateral parallel opposed fields, six hours after the first fraction. Thus, the total dose to the tumor and parametrial region was 59.4 Gy. A single brachytherapy procedure (Standard Tandem and Ovoids or Interstitial Template) was performed one week after the completion of external beam radiotherapy to bring the point A dose to 90 Gy in 6 weeks. Results: With a median follow-up of 30 months, (range: 5 to 42 months) the actuarial 3 year overall survival is 61.5% and the disease-free survival is 51.4%. Two out of twenty two patients (9.1%) had loco-regional failure alone, (5(22)) (22.7%) had distant failure only, and (4(22)) (18.2%) had both. The actuarial loco-regional control at 3 years is 69.5% with a distant metastasis-free survival of 57.5%. The median length of treatment was 46 days with a range of 35 to 107 days Most of the patients had only mild acute reactions, mainly diarrhea. There were no severe acute reactions. Thirteen of 22 patients (59.1%) had no late complications. Three patients had chronic proctitis, one with intermittent bleeding. Six (27.3%) patients experienced severe late complications consisting of vesico-vaginal fistulas, recto-vaginal fistulas and small bowel obstruction. One

  12. Local delivery of FTY720 accelerates cranial allograft incorporation and bone formation.

    Science.gov (United States)

    Huang, Cynthia; Das, Anusuya; Barker, Daniel; Tholpady, Sunil; Wang, Tiffany; Cui, Quanjun; Ogle, Roy; Botchwey, Edward

    2012-03-01

    Endogenous stem cell recruitment to the site of skeletal injury is key to enhanced osseous remodeling and neovascularization. To this end, this study utilized a novel bone allograft coating of poly(lactic-co-glycolic acid) (PLAGA) to sustain the release of FTY720, a selective agonist for sphingosine 1-phosphate (S1P) receptors, from calvarial allografts. Uncoated allografts, vehicle-coated, low dose FTY720 in PLAGA (1:200 w:w) and high dose FTY720 in PLAGA (1:40) were implanted into critical size calvarial bone defects. The ability of local FTY720 delivery to promote angiogenesis, maximize osteoinductivity and improve allograft incorporation by recruitment of bone progenitor cells from surrounding soft tissues and microcirculation was evaluated. FTY720 bioactivity after encapsulation and release was confirmed with sphingosine kinase 2 assays. HPLC-MS quantified about 50% loaded FTY720 release of the total encapsulated drug (4.5 μg) after 5 days. Following 2 weeks of defect healing, FTY720 delivery led to statistically significant increases in bone volumes compared to controls, with total bone volume increases for uncoated, coated, low FTY720 and high FTY720 of 5.98, 3.38, 7.2 and 8.9 mm(3), respectively. The rate and extent of enhanced bone growth persisted through week 4 but, by week 8, increases in bone formation in FTY720 groups were no longer statistically significant. However, micro-computed tomography (microCT) of contrast enhanced vascular ingrowth (MICROFIL®) and histological analysis showed enhanced integration as well as directed bone growth in both high and low dose FTY720 groups compared to controls.

  13. Accelerating SPARQL queries by exploiting hash-based locality and adaptive partitioning

    KAUST Repository

    Al-Harbi, Razen

    2016-02-08

    State-of-the-art distributed RDF systems partition data across multiple computer nodes (workers). Some systems perform cheap hash partitioning, which may result in expensive query evaluation. Others try to minimize inter-node communication, which requires an expensive data preprocessing phase, leading to a high startup cost. Apriori knowledge of the query workload has also been used to create partitions, which, however, are static and do not adapt to workload changes. In this paper, we propose AdPart, a distributed RDF system, which addresses the shortcomings of previous work. First, AdPart applies lightweight partitioning on the initial data, which distributes triples by hashing on their subjects; this renders its startup overhead low. At the same time, the locality-aware query optimizer of AdPart takes full advantage of the partitioning to (1) support the fully parallel processing of join patterns on subjects and (2) minimize data communication for general queries by applying hash distribution of intermediate results instead of broadcasting, wherever possible. Second, AdPart monitors the data access patterns and dynamically redistributes and replicates the instances of the most frequent ones among workers. As a result, the communication cost for future queries is drastically reduced or even eliminated. To control replication, AdPart implements an eviction policy for the redistributed patterns. Our experiments with synthetic and real data verify that AdPart: (1) starts faster than all existing systems; (2) processes thousands of queries before other systems become online; and (3) gracefully adapts to the query load, being able to evaluate queries on billion-scale RDF data in subseconds.

  14. Hearing loss due to concurrent daily low-dose cisplatin chemoradiation for locally advanced head and neck cancer

    International Nuclear Information System (INIS)

    Zuur, Charlotte L.; Simis, Yvonne J.W.; Verkaik, Roxanna S.; Schornagel, Jan H.; Balm, Alfons J.M.; Dreschler, Wouter A.; Rasch, Coen R.N.

    2008-01-01

    Background and purpose: Cisplatin-based chemo-irradiation (CRT) is increasingly used for head and neck squamous cell carcinoma (HNSCC). We aimed to assess hearing deterioration due to low-dose cisplatin chemoradiation and to compare the observed hearing loss with hearing loss in our previously described high-dose cisplatin CRT cohort. Materials and methods: A prospective analysis of hearing thresholds at low and (ultra)-high frequencies obtained before and after treatment in 60 patients. Patients received low-dose cisplatin (6 mg/m 2 , daily infusions, 20-25 days) with concomitant accelerated radiotherapy (70 Gy). Results: Audiometry up to 16 kHz was performed before therapy and 31 days (median) post-treatment. The total incidence of ototoxicity in CTCAEv3.0 was 31% in audiograms up to 8 kHz, and 5% of ears tested qualified for HAs due to treatment. The mean hearing loss at speech frequencies was 2.6 dB (SD 5.7) and 2.3 dB (SD 9.2) at PTA 1-2-4 kHz air-conduction and bone-conduction, respectively. The mean hearing loss at ultra-high frequencies (PTA AC 8-10-12.5 kHz) was 9.0 dB (SD 8.1). Low-dose cisplatin CRT caused less acute hearing loss (CTCAE 31%), compared to high-dose cisplatin CRT (CTCAE 78%). Conclusions: Low-dose cisplatin chemo-irradiation for HNSCC is a relatively safe treatment protocol with respect to ototoxicity

  15. A randomized study of accelerated fractionation radiotherapy with and without mitomycin C in the treatment of locally advanced head and neck cancer

    DEFF Research Database (Denmark)

    Ezzat, M.; Shouman, T.; Zaza, K.

    2005-01-01

    Objectives: This single-institution study evaluates the feasibility of accelerated fractionation radiotherapy (AF) with and without mitomycin C (MMC) in the treatment of locally advanced head and neck cancer. Patients and Methods: Between May 1998 and October 2001, sixty patients with locally...... advanced stage III and IV of head and neck cancer were randomized into three treatment arms: (1) conventional fractionation radiotherapy (CF) (5 fractions per week); (2) accelerated fractionation radiotherapy (AF) (6 fractions per week); and (3) AF plus Mitomycin C (MMC). Results: The 2-year overall....... Key Words: Head and Neck cancer , Radiotherapy , Altered fractionation , Mitomycin C....

  16. Phase 1 Dose Escalation Study of Accelerated Radiation Therapy With Concurrent Chemotherapy for Locally Advanced Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kelsey, Chris R., E-mail: christopher.kelsey@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Das, Shiva [Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina (United States); Gu, Lin [Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina (United States); Dunphy, Frank R.; Ready, Neal E. [Division of Medical Oncology, Department of Medicine, Duke University Medical Center, Durham, North Carolina (United States); Marks, Lawrence B. [Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina (United States)

    2015-12-01

    Purpose: To determine the maximum tolerated dose of radiation therapy (RT) given in an accelerated fashion with concurrent chemotherapy using intensity modulated RT. Methods and Materials: Patients with locally advanced lung cancer (non-small cell and small cell) with good performance status and minimal weight loss received concurrent cisplatin and etoposide with RT. Intensity modulated RT with daily image guidance was used to facilitate esophageal avoidance and delivered using 6 fractions per week (twice daily on Fridays with a 6-hour interval). The dose was escalated from 58 Gy to a planned maximum dose of 74 Gy in 4 Gy increments in a standard 3 + 3 trial design. Dose-limiting toxicity (DLT) was defined as acute grade 3-5 nonhematologic toxicity attributed to RT. Results: A total of 24 patients were enrolled, filling all dose cohorts, all completing RT and chemotherapy as prescribed. Dose-limiting toxicity occurred in 1 patient at 58 Gy (grade 3 esophagitis) and 1 patient at 70 Gy (grade 3 esophageal fistula). Both patients with DLTs had large tumors (12 cm and 10 cm, respectively) adjacent to the esophagus. Three additional patients were enrolled at both dose cohorts without further DLT. In the final 74-Gy cohort, no DLTs were observed (0 of 6). Conclusions: Dose escalation and acceleration to 74 Gy with intensity modulated RT and concurrent chemotherapy was tolerable, with a low rate of grade ≥3 acute esophageal reactions.

  17. Local Outbreak of Listeria monocytogenes Serotype 4b Sequence Type 6 Due to Contaminated Meat Pâté.

    Science.gov (United States)

    Althaus, Denise; Jermini, Marco; Giannini, Petra; Martinetti, Gladys; Reinholz, Danuta; Nüesch-Inderbinen, Magdalena; Lehner, Angelika; Stephan, Roger

    2017-04-01

    In January and February 2016, five cases of confirmed and two cases of probable infection due to Listeria monocytogenes serotype 4b, sequence type (ST) 6 belonging to a single pulsed-field gel electrophoresis pulsotype pattern were registered in a region of southern Switzerland. L. monocytogenes was detected in blood samples (four cases) and pleural fluid (one case). Furthermore, L. monocytogenes 4b ST6 was detected in a stool sample of an asymptomatic person exposed to a common food. Forthwith, the food safety authority and a local gourmet meat producer reported L. monocytogenes contamination of meat pâté. Analysis of further food and environmental samples from the premises of the producer yielded isolates matching the clinical strains and confirmed the presence of L. monocytogenes 4b ST6 in the mincing machine as the cause of the food contamination.

  18. External radiation in Dolon village due to local fallout from the first USSR atomic bomb test in 1949.

    Science.gov (United States)

    Imanaka, Tetsuji; Fukutani, Satoshi; Yamamoto, Masayoshi; Sakaguchi, Aya; Hoshi, Masaharu

    2006-02-01

    Dolon village, located about 60 km from the border of the Semipalatinsk Nuclear Test Site, is known to be heavily contaminated by local fallout from the first USSR atomic bomb test in 1949. External radiation in Dolon was evaluated based on recent 137Cs data in soil and calculation of temporal change in the fission product composition. After fitting a log-normal distribution to the soil data, a 137Cs deposition of 32 kBq m-2, which corresponds to the 90th-percentile of the distribution, was tentatively chosen as a value to evaluate the radiation situation in 1949. Our calculation indicated that more than 95% of the cumulative dose for 50 y had been delivered within 1 y after the deposition. The resulting cumulative dose for 1 y after the deposition, normalized to the initial contamination containing 1 kBq m-2 of 137Cs, was 15.6 mGy, assuming a fallout arrival time of 3 h and a medium level of fractionation. Finally, 0.50 Gy of absorbed dose in air was derived as our tentative estimate for 1-year cumulative external dose in Dolon due to local fallout from the first USSR test in 1949.

  19. Changes in intestinal intraepithelial lymphocytes due to local irradiation of a portion of the maxilla in mice

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Daigo; Tamazawa, Ken; Yosue, Takashi; Sakai, Yasuo; Suzuki, Masayuki [Nihon Univ., Tokyo (Japan). School of Dentistry; Arai, Chiaki; Inagaki, Hiroyuki

    2000-05-01

    We have been investigating the changes of lymphocyte subsets in the immune organs after head and neck irradiation. The present study investigated the influence due to local irradiation (10 Gy) of a portion of the maxilla on intestinal intraepithelial lymphocytes (i-IEL) in mice. We analyzed the percentage of subpopulations in i-IEL following irradiation using two-color fluorometry (anti-TCR{alpha}{beta}, TCR{gamma}{delta}, CD4 and CD8 monoclonal antibodies), and the outcome was compared with that obtained from non-irradiation groups. The result was that the percentage of {alpha}{beta}T cells, {gamma}{delta}T cells, CD4{sup +}SPT cells and CD8{sup +}SPT cells did not show any significant change and the fact differed from that in spleen and thymus where the percentage of these subpopulations was significantly changed. Although spleen and thymus reflect damaged lymphocytes that had circulated through the irradiation field, the result indicates that the balance among i-IEL subsets does not change after irradiation. The reason that equilibrium of i-IEL subsets remains stable seems related to localization of the small intestine and radioresistance. It was also indicated that the effect on the oral epithelium in the irradiation field reflects the percentages of i-IEL subsets. (author)

  20. Modeling the dynamics of the lead bismuth eutectic experimental accelerator driven system by an infinite impulse response locally recurrent neural network

    International Nuclear Information System (INIS)

    Zio, Enrico; Pedroni, Nicola; Broggi, Matteo; Golea, Lucia Roxana

    2009-01-01

    In this paper, an infinite impulse response locally recurrent neural network (IIR-LRNN) is employed for modelling the dynamics of the Lead Bismuth Eutectic eXperimental Accelerator Driven System (LBE-XADS). The network is trained by recursive back-propagation (RBP) and its ability in estimating transients is tested under various conditions. The results demonstrate the robustness of the locally recurrent scheme in the reconstruction of complex nonlinear dynamic relationships

  1. Advances in detecting localized road damage due to sinkholes induced by engineering works using high resolution RASARSAT-2 data

    Science.gov (United States)

    Chen, J.; Zebker, H. A.; Lakshmi, V.

    2016-12-01

    Sinkholes often occur in karst terrains such as found in central and eastern Pennsylvania. Voids produced by dissolution of carbonate rocks can result in soil transport leading to localized, gradual or rapid, sinking of the land surface. A cluster of sinkholes developed in 2000 around a small rural community beside Bushkill creek near a limestone quarry, and severely destroyed road bridges and railway tracks. At a cost of $6 million, the Pennsylvania DoT replaced the bridge, which was damaged again in 2004 by newly developed sinkholes likely associated with quarry's pumping activity. Here we present high-resolution spaceborne interferometric radar images of sinkhole development on this community. We show that this technique may be used to monitor regions with high sinkhole damage risk and assist future infrastructure route planning, especially in rural areas where hydrogeologic information is limited. Specifically, we processed 66 RADARSAT-2 interferograms to extract deformation occurred over Bushkill creek between Jun. 2015 and Mar. 2016 with a temporal resolution of 24 days. We advanced recent persistent scatterer techniques to preserve meter-level spatial resolution in the interferograms while minimizing temporal decorrelation and phase unwrapping error. We observe periodic deformation due to pumping activity at the quarry and localized subsidence along Bushkill creek that is co-located with recent reported sinkholes. We plan to use the automatic processing techniques developed for this study to study road damage in another region in Pennsylvania, along Lewiston Narrows, and also to monitor urban infrastructure improvements in Seattle, both again with RASARSAT-2 data. Our results demonstrate that recent advances in satellite geodesy can be transferred to benefit society beyond the science community.

  2. Use of novel sensors combining local positioning and acceleration to measure feeding behavior differences associated with lameness in dairy cattle.

    Science.gov (United States)

    Barker, Z E; Vázquez Diosdado, J A; Codling, E A; Bell, N J; Hodges, H R; Croft, D P; Amory, J R

    2018-04-25

    Time constraints for dairy farmers are an important factor contributing to the under-detection of lameness, resulting in delayed or missed treatment of lame cows within many commercial dairy herds. Hence, a need exists for flexible and affordable cow-based sensor systems capable of monitoring behaviors such as time spent feeding, which may be affected by the onset of lameness. In this study a novel neck-mounted mobile sensor system that combines local positioning and activity (acceleration) was tested and validated on a commercial UK dairy farm. Position and activity data were collected over 5 consecutive days for 19 high-yield dairy cows (10 lame, 9 nonlame) that formed a subset of a larger (120 cow) management group housed in a freestall barn. A decision tree algorithm that included sensor-recorded position and accelerometer data was developed to classify a cow as doing 1 of 3 categories of behavior: (1) feeding, (2) not feeding, and (3) out of pen for milking. For each classified behavior the mean number of bouts, the mean bout duration, and the mean total duration across all bouts was determined on a daily basis, and also separately for the time periods in between milking (morning = 0630-1300 h; afternoon = 1430-2100 h; night = 2230-0500 h). A comparative analysis of the classified cow behaviors was undertaken using a Welch t-test with Benjamini-Hochberg post-hoc correction under the null hypothesis of no differences in the number or duration of behavioral bouts between the 2 test groups of lame and nonlame cows. Analysis showed that mean total daily feeding duration was significantly lower for lame cows compared with non-lame cows. Behavior was also affected by time of day with significantly lower mean total duration of feeding and higher total duration of nonfeeding in the afternoons for lame cows compared with nonlame cows. The results demonstrate how sensors that measure both position and acceleration are capable of detecting differences in feeding behavior

  3. Rigorous treatment of the non-ohmic d.c. conductivity due to phonon-assisted tunneling from localized to extended states

    International Nuclear Information System (INIS)

    Majernikova, E.

    1984-03-01

    A quantitative treatment of the non-ohmic current response due to delocalization of shallow localized electrons in a model of a disordered solid is given. A phonon-assisted tunneling in electric field from shallow localized to extended states is confirmed as a mechanism leading to the dependence which was experimentally found for chalcogenide glasses. (author)

  4. Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)

    International Nuclear Information System (INIS)

    Hassona, Rifaat K.; Sam, A.K.; Osman, O.I.; Sirelkhatim, D.A.; LaRosa, J.

    2008-01-01

    An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing 210 Po and 137 Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of 210 Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of 210 Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (μSv/yr) in carnivores, omnivores and herbivores, respectively, for 137 Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For 210 Po, it was found to be 3.47, 4.81 and 4.14 (μSv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of 137 Cs is negligible compared to 210 Po

  5. Assessment of committed effective dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)

    International Nuclear Information System (INIS)

    Hassona, R. K; Sam, A. K; Sirelkhatim, D. A.; Osman, O. I.; Larosa, J.

    2008-01-01

    An assessment of committed effective dose (CED) due to consumption of Red Sea fish containing ''2''1''0Po and ''1''3''7Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of 2 ''1''0Po were found in the ranges 0.25-6.42 (carnivores), 0.7- 5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weigh, which were several times lower than those of ''2''1''0Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (μSv/Yr) in carnivores, omnivores and herbivores, respectively, for ''1'''3''7Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For ''2''1''0Po, it was found to be 3.47, 4.81and 4.14 (μSv/Yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish ). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of ''1''3''7Cs is negligible compared to ''2''1''0Po.(Author)

  6. Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan).

    Science.gov (United States)

    Hassona, Rifaat K; Sam, A K; Osman, O I; Sirelkhatim, D A; LaRosa, J

    2008-04-15

    An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing (210)Po and (137)Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of (210)Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of (210)Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (microSv/yr) in carnivores, omnivores and herbivores, respectively, for (137)Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For (210)Po, it was found to be 3.47, 4.81 and 4.14 (microSv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of (137)Cs is negligible compared to (210)Po.

  7. More fishers and fewer martens due to cumulative effects of forest management and climate change as evidenced from local knowledge.

    Science.gov (United States)

    Suffice, Pauline; Asselin, Hugo; Imbeau, Louis; Cheveau, Marianne; Drapeau, Pierre

    2017-09-07

    Monitoring of fur-bearing species populations is relatively rare due to their low densities. In addition to catch data, trappers' experience provides information on the ecology and status of the harvested species. Fisher (Pekania pennanti) and American marten (Martes americana) are mustelids that are sensitive to forest management and therefore considered to be ecological indicators of forest health. Fisher populations have increased in eastern North America since the early 2000s and this could have resulted in a northeastern extension of the species' range and increased overlap with marten's range. Moreover, habitats of both species are subject to natural and anthropogenic disturbances. The objective of this study was to document the knowledge held by local trappers in the northern area of sympatry between fisher and marten to identify factors that could explain variation in populations of the two species and interactions between them. Forty-one semi-directed interviews with Indigenous and non-Indigenous trappers in the Abitibi-Témiscamingue region of western Quebec (Canada), at the northern limit of the overlapping ranges of the two mustelid species. Trappers highlighted the lack of exclusivity of marten and fisher to coniferous forests, although marten is more closely associated with them than is fisher. Fisher apparently also takes advantage of open environments, including agroforestry systems. Moreover, climate change increases the frequency of freeze-thaw events that cause the formation of an ice crust on the snow surface, which favors fisher movements. The fisher was identified as a competitor and even a predator of the marten. Furthermore, the fisher is less affected than the marten by forest management, and it also seems to benefit from climate change to a greater extent.

  8. Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)

    Energy Technology Data Exchange (ETDEWEB)

    Hassona, Rifaat K. [Sudan Atomic Energy Commission, Khartoum, P.O. Box 3001 (Sudan)], E-mail: rifaatk@yahoo.com; Sam, A.K. [Sudan Atomic Energy Commission, Khartoum, P.O. Box 3001 (Sudan); Osman, O.I. [Chemistry Department, Faculty of Science, University of Khartoum (Sudan); Sirelkhatim, D.A. [Sudan Atomic Energy Commission, Khartoum, P.O. Box 3001 (Sudan); LaRosa, J. [Formerly at IAEA Marine Environment Laboratory, 4 Quai Antoine 1er, MC 98000 (Monaco)

    2008-04-15

    An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing {sup 210}Po and {sup 137}Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of {sup 210}Po were found in the ranges 0.25-6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1-0.46 (carnivores), 0.09-0.35 (omnivores) and 0.09-0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of {sup 210}Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 ({mu}Sv/yr) in carnivores, omnivores and herbivores, respectively, for {sup 137}Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For {sup 210}Po, it was found to be 3.47, 4.81 and 4.14 ({mu}Sv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of {sup 137}Cs is negligible compared to {sup 210}Po.

  9. Oocyte cryopreservation for fertility preservation in postpubertal female children at risk for premature ovarian failure due to accelerated follicle loss in Turner syndrome or cancer treatments.

    Science.gov (United States)

    Oktay, K; Bedoschi, G

    2014-12-01

    To preliminarily study the feasibility of oocyte cryopreservation in postpubertal girls aged between 13 and 15 years who were at risk for premature ovarian failure due to the accelerated follicle loss associated with Turner syndrome or cancer treatments. Retrospective cohort and review of literature. Academic fertility preservation unit. Three girls diagnosed with Turner syndrome, 1 girl diagnosed with germ-cell tumor. and 1 girl diagnosed with lymphoblastic leukemia. Assessment of ovarian reserve, ovarian stimulation, oocyte retrieval, in vitro maturation, and mature oocyte cryopreservation. Response to ovarian stimulation, number of mature oocytes cryopreserved and complications, if any. Mean anti-müllerian hormone, baseline follical stimulating hormone, estradiol, and antral follicle counts were 1.30 ± 0.39, 6.08 ± 2.63, 41.39 ± 24.68, 8.0 ± 3.2; respectively. In Turner girls the ovarian reserve assessment indicated already diminished ovarian reserve. Ovarian stimulation and oocyte cryopreservation was successfully performed in all female children referred for fertility preservation. A range of 4-11 mature oocytes (mean 8.1 ± 3.4) was cryopreserved without any complications. All girls tolerated the procedure well. Oocyte cryopreservation is a feasible technique in selected female children at risk for premature ovarian failure. Further studies would be beneficial to test the success of oocyte cryopreservation in young girls. Copyright © 2014 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

  10. Reverse Estuarine Circulation Due to Local and Remote Wind Forcing, Enhanced by the Presence of Along-Coast Estuaries

    Science.gov (United States)

    Giddings, S. N.; MacCready, P.

    2017-12-01

    Estuarine exchange flow governs the interaction between oceans and estuaries and thus plays a large role in their biogeochemical processes. This study investigates the variability in estuarine exchange flow due to offshore oceanic conditions including upwelling/downwelling, and the presence of a river plume offshore (from a neighboring estuary). We address these processes via numerical simulations at the mouth of the Salish Sea, a large estuarine system in the Northeast Pacific. An analysis of the Total Exchange Flow indicates that during the upwelling season, the exchange flow is fairly consistent in magnitude and oriented in a positive (into the estuary at depth and out at the surface) direction. However, during periods of downwelling favorable winds, the exchange flow shows significantly more variability including multiple reversals, consistent with observations, and surface intrusions of the Columbia River plume which originates 250 km to the south. Numerical along-strait momentum budgets show that the exchange flow is forced dominantly by the pressure gradients, particularly the baroclinic. The pressure gradient is modified by Coriolis and sometimes advection, highlighting the importance of geostrophy and local adjustments. In experiments conducted without the offshore river plume, reversals still occur but are weaker, and the baroclinic pressure gradient plays a reduced role. These results suggest that estuaries along strong upwelling coastlines should experience significant modulation in the exchange flow during upwelling versus downwelling conditions. Additionally, they highlight the importance of nearby estuaries impacting one-another, not only in terms of connectivity, but also altering the exchange flow.Plain Language SummaryEstuarine systems provide extensive biological and ecological functions as well as contribute to human uses and economies. However, estuaries are susceptible to change and most estuaries have been significantly impacted, threatening

  11. Local processing enhancements associated with superior observational drawing are due to enhanced perceptual functioning, not weak central coherence.

    Science.gov (United States)

    Chamberlain, Rebecca; McManus, I C; Riley, Howard; Rankin, Qona; Brunswick, Nicola

    2013-01-01

    Individuals with drawing talent have previously been shown to exhibit enhanced local visual processing ability. The aim of the current study was to assess whether local processing biases associated with drawing ability result from a reduced ability to cohere local stimuli into global forms, or an increased ability to disregard global aspects of an image. Local and global visual processing ability was assessed in art students and controls using the Group Embedded Figures Task, Navon shape stimuli, the Block Design Task and the Autism Spectrum Quotient, whilst controlling for nonverbal IQ and artistic ability. Local processing biases associated with drawing appear to arise from an enhancement of local processing alongside successful filtering of global information, rather than a reduction in global processing. The relationship between local processing and drawing ability is independent of individual differences in nonverbal IQ and artistic ability. These findings have implications for bottom-up and attentional theories of observational drawing, as well as explanations of special skills in autism.

  12. Amplification of Surface-Enhanced Raman Scattering Due to Substrate-Mediated Localized Surface Plasmons in Gold Nanodimers

    KAUST Repository

    Yue, Weisheng; Wang, Zhihong; Whittaker, John; Lopez-royo, Francisco; Yang, Yang; Zayats, Anatoly

    2017-01-01

    that significant improvement in a SERS signal can be achieved with substrates combining localized surface plasmon resonances and a nonresonant plasmonic substrate. By introducing a continuous gold (Au) film underneath Au nanodimers antenna arrays, an over 10-fold

  13. Deriving appropriate boundary conditions, and accelerating position-jump simulations, of diffusion using non-local jumping

    International Nuclear Information System (INIS)

    Taylor, P R; Baker, R E; Yates, C A

    2015-01-01

    In this paper we explore lattice-based position-jump models of diffusion, and the implications of introducing non-local jumping; particles can jump to a range of nearby boxes rather than only to their nearest neighbours. We begin by deriving conditions for equivalence with traditional local jumping models in the continuum limit. We then generalize a previously postulated implementation of the Robin boundary condition for a non-local process of arbitrary maximum jump length, and present a novel implementation of flux boundary conditions, again generalized for a non-local process of arbitrary maximum jump length. In both these cases we validate our results using stochastic simulation. We then proceed to consider two variations on the basic diffusion model: a hybrid local/non-local scheme suitable for models involving sharp concentration gradients, and the implementation of biased jumping. In all cases we show that non-local jumping can deliver substantial time savings for stochastic simulations. (paper)

  14. Clinicohistopathological correlations in juvenile localized scleroderma: studies on a subset of children with hypopigmented juvenile localized scleroderma due to loss of epidermal melanocytes.

    Science.gov (United States)

    Sung, Joanne J; Chen, Tina S; Gilliam, Anita C; McCalmont, Timothy H; Gilliam, Amy E

    2011-08-01

    Localized scleroderma or morphea is a connective tissue disorder characterized by fibrosis of the skin and subcutaneous tissue. Excessive accumulation of collagen underlies the fibrosis, yet the pathogenesis is unknown. A subset of localized scleroderma/morphea, juvenile localized scleroderma (JLS), affects children and adolescents. The clinical and microscopic features of JLS have not been fully characterized. The goal is to better characterize the microscopic features of JLS. We collected a distinctive data set of 35 children with JLS, 19 (54%) of whom presented with hypopigmented lesions, and performed a retrospective chart and pathology review. We had adequate tissue for immunostaining studies on 8 of these individuals. We found that: (1) CD34 and factor XIIIa immunostaining, reported previously in adult morphea and scleroderma, when used with clinical information, is valuable for confirming a diagnosis of JLS; and (2) presence of hypopigmented lesions in JLS correlates with immunostaining studies. Decreased numbers of MelanA(+) melanocytes were present at the dermoepidermal junction in lesional skin in two of 3 children with hypopigmented JLS and in two of 4 children with nonhypopigmented JLS. The number of cases is small, a function of the small number of children who have biopsy specimens with material sufficient for multiple immunostaining procedures. These results provide a useful immunostaining method for confirmation of the diagnosis of JLS. They suggest a complex autoimmune phenotype in some children with JLS. Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  15. A high resolution interferometric method to measure local swelling due to CO2 exposure in coal and shale

    NARCIS (Netherlands)

    Pluymakers, A.; Liu, J.; Kohler, F.; Renard, F.; Dysthe, D.

    2018-01-01

    We present an experimental method to study time-dependent, CO2-induced, local topography changes in mm-sized composite samples, plus results showing heterogeneous swelling of coal and shale on the nano- to micrometer scale. These results were obtained using high resolution interferometry

  16. Increase in protoporphyrin IX after 5-aminolevulinic acid based photodynamic therapy is due to local re-synthesis

    NARCIS (Netherlands)

    de Bruijn, Henriëtte S.; Kruijt, Bastiaan; van der Ploeg-van den Heuvel, Angélique; Sterenborg, Henricus J. C. M.; Robinson, Dominic J.

    2007-01-01

    Protoporphyrin IX (PpIX) fluorescence that is bleached during aminolevulinic acid (ALA) mediated photodynamic therapy (PDT) increases again in time after treatment. In the present study we investigated if this increase in PpIX fluorescence after illumination is the result of local re-synthesis or of

  17. Amplification of Surface-Enhanced Raman Scattering Due to Substrate-Mediated Localized Surface Plasmons in Gold Nanodimers

    KAUST Repository

    Yue, Weisheng

    2017-03-28

    Surface-enhanced Raman scattering (SERS) is ubiquitous in chemical and biochemical sensing, imaging and identification. Maximizing SERS enhancement is a continuous effort focused on the design of appropriate SERS substrates. Here we show that significant improvement in a SERS signal can be achieved with substrates combining localized surface plasmon resonances and a nonresonant plasmonic substrate. By introducing a continuous gold (Au) film underneath Au nanodimers antenna arrays, an over 10-fold increase in SERS enhancement is demonstrated. Triangular, rectangle and disc dimers were studied, with bowtie antenna providing highest SERS enhancement. Simulations of electromagnetic field distributions of the Au nanodimers on the Au film support the observed enhancement dependences. The hybridization of localized plasmonic modes with the image modes in a metal film provides a straightforward way to improve SERS enhancement in designer SERS substrate.

  18. Accelerated radiation therapy for locally advanced squamous cell carcinomas of the oral cavity and oropharynx selected according to tumor cell kinetics--a phase II multicenter study

    International Nuclear Information System (INIS)

    Antognoni, Paolo; Bignardi, Mario; Cazzaniga, L. Franco; Poli, A. Marisa; Richetti, Antonella; Bossi, Alberto; Rampello, Giuseppina; Barbera, Fernando; Soatti, Carlo; Bardelli, Donata; Giordano, Monica; Danova, Marco

    1996-01-01

    Purpose: A Phase II multicenter trial testing an accelerated regimen of radiotherapy in locally advanced and inoperable cancers of the head and neck, in patients selected on the basis of 5-bromo-2-deoxyuridine/DNA flow cytometry-derived tumor potential doubling time (T pot ). Methods and Materials: From September 1992 to September 1993, 23 patients consecutively diagnosed to have locally advanced, inoperable carcinomas of the oral cavity and the oropharynx, with T pot of ≤5 days, received an accelerated radiotherapy regimen (AF) based on a modification of the concomitant boost technique: 2 Gy/fraction once a day, delivered 5 days a week up to 26 Gy, followed by 2 Gy/fraction twice a day, with a 6-h interval, one of the two fractions being delivered as a concomitant boost to reduced fields, up to 66 Gy total dose (off-cord reduction at 46 Gy), shortening the overall treatment time to 4.5 weeks. A contemporary control group of 46 patients with T pot of >5 days or unknown was treated with conventional fractionation (CF): 2 Gy/fraction once a day, 5 days a week, up to 66 Gy in 6.5 weeks, with fields shrinkage after 46 Gy. Results: All patients completed the accelerated regimen according to protocol and in the prescribed overall treatment time. Immediate tolerance was fairly good: 65% of the patients in the AF group experienced Grade 3 mucositis vs. 45% in the CF group (p = n.s.). Symptoms related to mucosal reactions seemed to persist longer in AF than in CF patients. The crude proportion of mild (Grades 1 and 2) late effects on skin (p < 0.01) and salivary glands (p < 0.05) was higher in AF than in CF patients, although these reactions did not exceed the limits of tolerance. Three patients in the AF and 1 in the CF arm experienced a late Grade 4 bone complication. Actuarial estimates of severe (Grades 3 and 4) late complications showed a 2-year hazard of 33.3% in the AF arm and 49.7% in CF (p = NS). The actuarial 2-year local control rate of the AF patients was 49

  19. Collaboration of local government and experts responding to increase in environmental radiation level due to the nuclear disaster: focusing on their activities and latest radiological discussion

    International Nuclear Information System (INIS)

    Iimoto, T.; Nunokawa, J.; Fujii, H.; Takashima, R.; Hashimoto, M.; Fukuhara, T.; Yajima, T.; Matsuzawa, H.; Kurosawa, K.; Yanagawa, Y.; Someya, S.

    2015-01-01

    Activities were introduced in Kashiwa city in the Tokyo metropolitan area to correspond to the elevated environmental radiation level after the disaster of the Fukushima Daiichi nuclear power plant. These were based on a strong cooperation between local governments and experts. Ambient dose rate and radioactivity of foodstuff produced inside of the city have been monitored. Representative ambient dose rates around living environments have almost already become their original levels of the pre-accident because of the decontamination activity, natural washout and effective half-lives of radioactivity. The internal annual dose due to radioactive cesium under the policy of 'Local Production for Local Consumption' is estimated as extremely low comparing the variation range due to natural radioactivity. Systematic survey around a retention basin has been started. All of these latest monitoring data would be one of the core information for the policy making as well as a cost-benefit discussion and risk communication. (authors)

  20. Acceleration of the charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

    International Nuclear Information System (INIS)

    Stuchlik, Zdenek; Kolos, Martin

    2016-01-01

    To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)

  1. Acceleration of the charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Stuchlik, Zdenek; Kolos, Martin [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Opava (Czech Republic)

    2016-01-15

    To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)

  2. Calculation of skin dose due to beta contamination using the new quantity of the ICRP 116: the local skin dose

    International Nuclear Information System (INIS)

    Bourgois, L.; Menard, S.; Comte, N.

    2017-01-01

    Values of the new protection quantity Local Skin Dose 'LSD', introduced by the International Commission on Radiological Protection (ICRP) Publication 116, were calculated for 134 β - or β + emitting radionuclides, using the Monte Carlo code MCNP6. Two types of source geometry are considered: a point source and disc-type surface contamination (the source is placed in contact with the skin). This new protection quantity is compared with the operational quantity H2 (0.07, 0 deg.), leading us to conclude that, in accordance with the rules of the ICRP, the operational quantity over-estimates the protection quantity to a reasonable extent, except in very rare cases for very low average beta energies. Thus, with the new skin model described in ICRP 116, there are no longer any major differences between the operational quantities and protection quantities estimated with the skin model described in ICRP 74. (authors)

  3. Exceptional increase in the creep life of magnesium rare-earth alloys due to localized bond stiffening.

    Science.gov (United States)

    Choudhuri, Deep; Srinivasan, Srivilliputhur G; Gibson, Mark A; Zheng, Yufeng; Jaeger, David L; Fraser, Hamish L; Banerjee, Rajarshi

    2017-12-08

    Several recent papers report spectacular, and unexpected, order of magnitude improvement in creep life of alloys upon adding small amounts of elements like zinc. This microalloying effect raises fundamental questions regarding creep deformation mechanisms. Here, using atomic-scale characterization and first principles calculations, we attribute the 600% increase in creep life in a prototypical Mg-rare earth (RE)-Zn alloy to multiple mechanisms caused by RE-Zn bonding-stabilization of a large volume fraction of strengthening precipitates on slip planes, increase in vacancy diffusion barrier, reduction in activated cross-slip, and enhancement of covalent character and bond strength around Zn solutes along the c-axis of Mg. We report that increased vacancy diffusion barrier, which correlates with the observed 25% increase in interplanar bond stiffness, primarily enhances the high-temperature creep life. Thus, we demonstrate that an approach of local, randomized tailoring of bond stiffness via microalloying enhances creep performance of alloys.

  4. Measurements of local mass transfer coefficient of Flow Accelerated Corrosion at feeder outlet pipes in CANDU using Plaster of Paris method

    International Nuclear Information System (INIS)

    Hyuk Kwon; Dong Un Seo; Goon-Cherl Park

    2005-01-01

    Full text of publication follows: Flow Accelerated Corrosion (FAC) is a corrosion mechanism that results in wall thinning in piping systems and components. FAC on carbon steels in pure water has occurred in a number of industry and power plant. A pipe wall thinning due to the FAC at nuclear power plant is just reported in confined to carbon steel pipe on the secondary system which does not equip a radioactive component. Recently, at Canadian Deuterium Uranium type reactor, it is reported that the feeder lines suffer the wall thinning on the primary system to equip 380 feeder pipes. Differently from the fast FAC rate of the secondary system on PWR, FAC rate of feeder pipes on CANDU is not more than the 0.2 mm/year. Although the FAC rate of feeder pipe is relatively slow, the narrow thickness margin of 2.6089 mm is endangered sufficiently by only the slow FAC rate. The FAC is governed by the mass transfer coefficient which is determined by the flow field. To well predict the FAC rate, mass transfer coefficient should be well measured or calculated. New measurement method of mass transfer coefficient is developed to obtain the coefficient for the complex shape like feeder pipe. The method evaluated the naphthalene sublimation method to apply it under the water flow. The naphthalene sublimation method can be used to study mass and heat transfer with confidence for a variety of applications, but with certain restrictions. At present, Plaster of paris method can modified the sublimation method to overcome the restrictions. This method is particularly useful in complex flows on geometries and for flows with large gradients in wall transport rate. The test specimen can be easily prepared by several methods, including dipping, machining, spraying, and casting. The local transfer coefficients can be determined with high accuracy and in detail by automated measurement systems that eliminate most human errors during the measurement process. To evaluate the method, the

  5. A meta-analysis of hyperfractionated and accelerated radiotherapy and combined chemotherapy and radiotherapy regimens in unresected locally advanced squamous cell carcinoma of the head and neck

    Directory of Open Access Journals (Sweden)

    Budach V

    2006-01-01

    Full Text Available Abstract Background Former meta-analyses have shown a survival benefit for the addition of chemotherapy (CHX to radiotherapy (RT and to some extent also for the use of hyperfractionated radiation therapy (HFRT and accelerated radiation therapy (AFRT in locally advanced squamous cell carcinoma (SCC of the head and neck. However, the publication of new studies and the fact that many older studies that were included in these former meta-analyses used obsolete radiation doses, CHX schedules or study designs prompted us to carry out a new analysis using strict inclusion criteria. Methods Randomised trials testing curatively intended RT (≥60 Gy in >4 weeks/>50 Gy in Results Thirty-two trials with a total of 10 225 patients were included into the meta-analysis. An overall survival benefit of 12.0 months was observed for the addition of simultaneous CHX to either CFRT or HFRT/AFRT (p Conclusion RT combined with simultaneous 5-FU, cisplatin, carboplatin, and mitomycin C as single drug or combinations of 5-FU with one of the other drugs results in a large survival advantage irrespective the employed radiation schedule. If radiation therapy is used as single modality, hyperfractionation leads to a significant improvement of overall survival. Accelerated radiation therapy alone, especially when given as split course radiation schedule or extremely accelerated treatments with decreased total dose, does not increase overall survival.

  6. Accelerated Partial Breast Irradiation With Low-Dose-Rate Interstitial Implant Brachytherapy After Wide Local Excision: 12-Year Outcomes From a Prospective Trial

    Energy Technology Data Exchange (ETDEWEB)

    Hattangadi, Jona A. [Harvard Radiation Oncology Program, Boston, MA (United States); Powell, Simon N. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); MacDonald, Shannon M.; Mauceri, Thomas; Ancukiewicz, Marek [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Freer, Phoebe [Department of Radiology, Massachusetts General Hospital, Boston, MA (United States); Lawenda, Brian [21st Century Oncology, Las Vegas, NV (United States); Alm El-Din, Mohamed A. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Department of Clinical Oncology, Tanta University Hospital, Tanta (Egypt); Gadd, Michele A.; Smith, Barbara L. [Department of Surgical Oncology, Massachusetts General Hospital, Boston, MA (United States); Taghian, Alphonse G., E-mail: ataghian@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States)

    2012-07-01

    Purpose: To evaluate the long-term toxicity, cosmesis, and local control of accelerated partial breast irradiation with implant brachytherapy after wide local excision for Stage T1N0 breast cancer (BCa). Materials and Methods: Between 1997 and 2001, 50 patients with Stage T1N0M0 BCa were treated in a Phase I-II protocol using low-dose-rate accelerated partial breast irradiation with implant brachytherapy after wide local excision and lymph node surgery. The total dose was escalated in three groups: 50 Gy (n = 20), 55 Gy (n = 17), and 60 Gy (n = 13). Patient- and physician-assessed breast cosmesis, patient satisfaction, toxicity, mammographic abnormalities, repeat biopsies, and disease status were prospectively evaluated at each visit. Kendall's tau ({tau}{sub {beta}}) and logistic regression analyses were used to correlate outcomes with dose, implant volume, patient age, and systemic therapy. Results: The median follow-up period was 11.2 years (range, 4-14). The patient satisfaction rate was 67%, 67% reported good-excellent cosmesis, and 54% had moderate-severe fibrosis. Higher dose was correlated with worse cosmetic outcome ({tau}{sub {beta}} 0.6, p < .0001), lower patient satisfaction ({tau}{sub {beta}} 0.5, p < .001), and worse fibrosis ({tau}{sub {beta}} 0.4, p = .0024). Of the 50 patients, 35% had fat necrosis and 34% developed telangiectasias {>=}1 cm{sup 2}. Grade 3-4 late skin and subcutaneous toxicities were seen in 4 patients (9%) and 6 patients (13%), respectively, and both correlated with higher dose ({tau}{sub {beta}} 0.3-0.5, p {<=} .01). One patient had Grade 4 skin ulceration and fat necrosis requiring surgery. Mammographic abnormalities were seen in 32% of the patients, and 30% underwent repeat biopsy, of which 73% were benign. Six patients had ipsilateral breast recurrence: five elsewhere in the breast, and one at the implant site. One patient died of metastatic BCa after recurrence. The 12-year actuarial local control, recurrence

  7. Accelerated Partial Breast Irradiation With Low-Dose-Rate Interstitial Implant Brachytherapy After Wide Local Excision: 12-Year Outcomes From a Prospective Trial

    International Nuclear Information System (INIS)

    Hattangadi, Jona A.; Powell, Simon N.; MacDonald, Shannon M.; Mauceri, Thomas; Ancukiewicz, Marek; Freer, Phoebe; Lawenda, Brian; Alm El-Din, Mohamed A.; Gadd, Michele A.; Smith, Barbara L.; Taghian, Alphonse G.

    2012-01-01

    Purpose: To evaluate the long-term toxicity, cosmesis, and local control of accelerated partial breast irradiation with implant brachytherapy after wide local excision for Stage T1N0 breast cancer (BCa). Materials and Methods: Between 1997 and 2001, 50 patients with Stage T1N0M0 BCa were treated in a Phase I-II protocol using low-dose-rate accelerated partial breast irradiation with implant brachytherapy after wide local excision and lymph node surgery. The total dose was escalated in three groups: 50 Gy (n = 20), 55 Gy (n = 17), and 60 Gy (n = 13). Patient- and physician-assessed breast cosmesis, patient satisfaction, toxicity, mammographic abnormalities, repeat biopsies, and disease status were prospectively evaluated at each visit. Kendall’s tau (τ β ) and logistic regression analyses were used to correlate outcomes with dose, implant volume, patient age, and systemic therapy. Results: The median follow-up period was 11.2 years (range, 4–14). The patient satisfaction rate was 67%, 67% reported good-excellent cosmesis, and 54% had moderate-severe fibrosis. Higher dose was correlated with worse cosmetic outcome (τ β 0.6, p β 0.5, p β 0.4, p = .0024). Of the 50 patients, 35% had fat necrosis and 34% developed telangiectasias ≥1 cm 2 . Grade 3–4 late skin and subcutaneous toxicities were seen in 4 patients (9%) and 6 patients (13%), respectively, and both correlated with higher dose (τ β 0.3–0.5, p ≤ .01). One patient had Grade 4 skin ulceration and fat necrosis requiring surgery. Mammographic abnormalities were seen in 32% of the patients, and 30% underwent repeat biopsy, of which 73% were benign. Six patients had ipsilateral breast recurrence: five elsewhere in the breast, and one at the implant site. One patient died of metastatic BCa after recurrence. The 12-year actuarial local control, recurrence-free survival, and overall survival rate was 85% (95% confidence interval, 70–97%), 72% (95% confidence interval, 54–86%), and 87% (95

  8. Preliminary Experience in Treatment of Papillary and Macular Retinoblastoma: Evaluation of Local Control and Local Complications After Treatment With Linear Accelerator-Based Stereotactic Radiotherapy With Micromultileaf Collimator as Second-Line or Salvage Treatment After Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Pica, Alessia, E-mail: Alessia.Pica@chuv.ch [Department of Radiation Oncology, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Moeckli, Raphael [University Institute for Radiation Physics, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Balmer, Aubin [Department of Radiation Oncology, Jules Gonin Eye Hospital, Lausanne (Switzerland); Beck-Popovic, Maja [Unit of Pediatric Oncology, University of Lausanne, Lausanne (Switzerland); Chollet-Rivier, Madeleine [Department of Anesthesiology, University of Lausanne, Lausanne (Switzerland); Do, Huu-Phuoc [University Institute for Radiation Physics, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Weber, Damien C. [Department of Radiation Oncology, Geneva University Hospital, University of Geneva, Geneva (Switzerland); Munier, Francis L. [Department of Radiation Oncology, Jules Gonin Eye Hospital, Lausanne (Switzerland)

    2011-12-01

    Purpose: To determine the local control and complication rates for children with papillary and/or macular retinoblastoma progressing after chemotherapy and undergoing stereotactic radiotherapy (SRT) with a micromultileaf collimator. Methods and Materials: Between 2004 and 2008, 11 children (15 eyes) with macular and/or papillary retinoblastoma were treated with SRT. The mean age was 19 months (range, 2-111). Of the 15 eyes, 7, 6, and 2 were classified as International Classification of Intraocular Retinoblastoma Group B, C, and E, respectively. The delivered dose of SRT was 50.4 Gy in 28 fractions using a dedicated micromultileaf collimator linear accelerator. Results: The median follow-up was 20 months (range, 13-39). Local control was achieved in 13 eyes (87%). The actuarial 1- and 2-year local control rates were both 82%. SRT was well tolerated. Late adverse events were reported in 4 patients. Of the 4 patients, 2 had developed focal microangiopathy 20 months after SRT; 1 had developed a transient recurrence of retinal detachment; and 1 had developed bilateral cataracts. No optic neuropathy was observed. Conclusions: Linear accelerator-based SRT for papillary and/or macular retinoblastoma in children resulted in excellent tumor control rates with acceptable toxicity. Additional research regarding SRT and its intrinsic organ-at-risk sparing capability is justified in the framework of prospective trials.

  9. Accelerating Value Creation with Accelerators

    DEFF Research Database (Denmark)

    Jonsson, Eythor Ivar

    2015-01-01

    and developing the best business ideas and support the due diligence process. Even universities are noticing that the learning experience of the action learning approach is an effective way to develop capabilities and change cultures. Accelerators related to what has historically been associated...

  10. [Histopathological changes due to transurethural microwave thermotherapy associated with androgen deprivation therapy in patients with localized prostate cancer].

    Science.gov (United States)

    Jujo, Yutaka; Koshiba, Ken; Suzuki, Ryuta; Hoshiai, Osamu; Endo, Tadao; Aihara, Masahiro; Katsuta, Masayuki; Nakajo, Hirotaka

    2006-03-01

    The 2nd generation transurethral microwave thermotherapy (TUMT), equipped with high energy microwave generator and urethral cooling device is widely accepted as an less invasive effective modality to treat benign prostatic hyperplasia. For prostatic cancer, however, it is generally estimated as insufficient because of limitation in penetration of microwave into deep prostatic tissue. In this study, we examined histopathologic changes after androgen deprivation theraphy (ADT) and TUMT. Ten patients with localized prostate cancer underwent ADT for 3 months, and then TUMT was proceeded using Urowave (Dornier MedTech GmbH). Additional 3 months after TUMT and continued ADT, TURP in radical fashion was performed in all the patients, and all the resected chips were submitted for pathological study. Significant reduction in prostate volume was noted after NHT for 3 months from 37.4 +/- 9.6 ml to 22.0 +/- 5.6 ml. The pathological study of resected chips revealed progressive fibrotic changes without viable cancer cells in 9 of 10 patients. In 1 patient, however, some remnant of carcinomatous foci were noted in a resected chip from the middle lobe of the prostate. Although the number of patient is limited and longer follow-up is needed, the results in present series was interested and worth considering.

  11. local

    Directory of Open Access Journals (Sweden)

    Abílio Amiguinho

    2005-01-01

    Full Text Available The process of socio-educational territorialisation in rural contexts is the topic of this text. The theme corresponds to a challenge to address it having as main axis of discussion either the problem of social exclusion or that of local development. The reasons to locate the discussion in this last field of analysis are discussed in the first part of the text. Theoretical and political reasons are there articulated because the question is about projects whose intentions and practices call for the political both in the theoretical debate and in the choices that anticipate intervention. From research conducted for several years, I use contributions that aim at discuss and enlighten how school can be a potential locus of local development. Its identification and recognition as local institution (either because of those that work and live in it or because of those that act in the surrounding context are crucial steps to progressively constitute school as a partner for development. The promotion of the local values and roots, the reconstruction of socio-personal and local identities, the production of sociabilities and the equation and solution of shared problems were the dimensions of a socio-educative intervention, markedly globalising. This scenario, as it is argued, was also, intentionally, one of transformation and of deliberate change of school and of the administration of the educative territoires.

  12. Changes in T cell populations due to local irradiation of a portion of the maxilla in mice

    International Nuclear Information System (INIS)

    Satoh, Daigo

    1997-01-01

    The aim of this study was to investigate the changes in the immune organs after head and neck irradiation. The numbers of lymphocytes in peripheral blood, the spleen and the thymus following local irradiation of a portion of the maxilla in mice were studied using three-color fluorometry and were compared with a non-irradiation group. In the peripheral blood, the absolute numbers of T cells, CD4 + SP cells and CD8 + SP cells decreased after irradiation, and the period of the decrease was longer than the decreases in number of leukocytes and lymphocytes. The ratio of CD4 + SP cells showed a significant decrease, and the ratio of CD8+ S P cells showed a significant increase 1 day after irradiation. In the spleen, the absolute number of T cells, the radio of CD4 + SP and CD8 + SP cell subsets showed a decrease, and the period of the decrease was longer than the decrease of the wet-weight of the spleen, and also longer than the decrease of the number of leukocytes. The number of CD4 + SP cells showed a signigicant increase, and CD8 + SP cells showed a significant decrease 21 days after irradiation. In the thymus, the absolute number of TCR αβ-thymocytes did not show a significant decrease. However, the number of DN thymocytes showed a marked decrease. These results indicate that the numbers of T cells in peripheral blood, the spleen and the thymus change immediately after irradiation, and the numbers of lymphocytes and the T cells in the spleen recover more slowly than that in the peripheral blood. As lymphoid tissues showed the suppression of immunological response for a long period, it was suggested that lymphoid tissues have to be observed carefully after irradiation to prevent cancer metastasis. (K.H.)

  13. Randomized phase III trial of concurrent chemoradiotherapy vs accelerated hyperfractionation radiotherapy in locally advanced head and neck cancer

    International Nuclear Information System (INIS)

    Chitapanarux, Imjai; Kamnerdsupaphon, Pimkhuan; Pukanhapan, Nantaka; Tharavichitkul, Ekkasit; Vongtama, Roy

    2013-01-01

    The aim of this study was to compare the efficacy and safety of concurrent chemoradiotherapy (CCRT) vs accelerated hyperfractionation with concomitant boost (CCB) as a primary treatment for patients with Stage III-IV squamous cell carcinoma of head and neck (SCCHN). A total of 85 non-metastatic advanced SCCHN patients were accrued from January 2003 to December 2007. Of these, 48 and 37 patients received CCRT and CCB, respectively. The patients were randomized to receive either three cycles of carboplatin and 5-fluorouracil plus conventional radiotherapy (CCRT, 66 Gy in 6.5 weeks) or hybrid accelerated radiotherapy (CCB, 70 Gy in 6 weeks). The primary endpoint was determined by locoregional control rate. The secondary endpoints were overall survival and toxicity. With a median follow-up of 43 months (range, 3-102), the 5-year locoregional control rate was 69.6% in the CCRT arm vs 55.0% in the CCB arm (P = 0.184). The 5-year overall survival rate was marginally significantly different (P = 0.05): 76.1% in the CCRT arm vs 63.5% in the CCB arm. Radiotherapy treatment interruptions of more than three days were 60.4% and 40.5% in the CCRT arm and CCB arm, respectively. The median total treatment time was 55.5 days in the CCRT arm and 49 days in the CCB arm. The rate of Grade 3 - 4 acute mucositis was significantly higher in the CCB arm (67.6% vs 41.7%, P = 0.01), but no high grade hematologic toxicities were found in the CCB arm (27.2% vs 0%). CCRT has shown a trend of improving outcome over CCB irradiation in locoregionally advanced head and neck cancer. (author)

  14. Cerebrovascular/cardiovascular diseases and mental disorders due to overwork and work-related stress among local public employees in Japan.

    Science.gov (United States)

    Yamauchi, Takashi; Yoshikawa, Toru; Sasaki, Takeshi; Matsumoto, Shun; Takahashi, Masaya; Suka, Machi; Yanagisawa, Hiroyuki

    2018-02-07

    In Japan, overwork-related disorders occur among local public employees as well as those in private businesses. However, to date, there are no studies reporting the state of compensation for cerebrovascular/cardiovascular diseases (CCVD) and mental disorders due to overwork or work-related stress among local public employees in Japan over multiple years. This report examined the recent trend of overwork-related CCVD and mental disorders, including the incidence rates of these disorders, among local public employees in Japan from the perspective of compensation for public accidents, using data from the Japanese Government and relevant organizations. Since 2000, compared to CCVD, there has been an overall increase in the number of claims and cases of compensation for mental disorders. Over half of the individuals receiving compensation for mental disorders were either in their 30s or younger. About 47% of cases of mental disorders were compensated due to work-related factors other than long working hours. The incidence rate by job type was highest among "police officials" and "fire department officials" for compensated CCVD and mental disorders cases, respectively. Changes in the trend of overwork-related disorders among local public employees in Japan under a legal foundation should be closely monitored.

  15. Limits to benthic feeding by eiders in a vital Arctic migration corridor due to localized prey and changing sea ice

    Science.gov (United States)

    Lovvorn, James R.; Rocha, Aariel R.; Jewett, Stephen C.; Dasher, Douglas; Oppel, Steffen; Powell, Abby

    2015-01-01

    Four species of threatened or declining eider ducks that nest in the Arctic migrate through the northeast Chukchi Sea, where anticipated industrial development may require prioritizing areas for conservation. In this nearshore corridor (10–40 m depth), the eiders’ access to benthic prey during the spring is restricted to variable areas of open water within sea ice. For the most abundant species, the king eider (Somateria spectabilis), stable isotopes in blood cells, muscle, and potential prey indicate that these eiders ate mainly bivalves when traversing this corridor. Bivalves there were much smaller than the same taxa in deeper areas of the northern Bering Sea, possibly due to higher mortality rates caused by ice scour in shallow water; future decrease in seasonal duration of fast ice may increase this effect. Computer simulations suggested that if these eiders forage for >15 h/day, they can feed profitably at bivalve densities >200 m−2 regardless of water depth or availability of ice for resting. Sampling in 2010–2012 showed that large areas of profitable prey densities occurred only in certain locations throughout the migration corridor. Satellite data in April–May over 13 years (2001–2013) indicated that access to major feeding areas through sea ice in different segments of the corridor can vary from 0% to 100% between months and years. In a warming and increasingly variable climate, unpredictability of access may be enhanced by greater effects of shifting winds on unconsolidated ice. Our results indicate the importance of having a range of potential feeding areas throughout the migration corridor to ensure prey availability in all years. Spatial planning of nearshore industrial development in the Arctic, including commercial shipping, pipeline construction, and the risk of released oil, should consider these effects of high environmental variability on the adequacy of habitats targeted for conservation.

  16. Phase precession through acceleration of local theta rhythm: a biophysical model for the interaction between place cells and local inhibitory neurons.

    Science.gov (United States)

    Castro, Luísa; Aguiar, Paulo

    2012-08-01

    Phase precession is one of the most well known examples within the temporal coding hypothesis. Here we present a biophysical spiking model for phase precession in hippocampal CA1 which focuses on the interaction between place cells and local inhibitory interneurons. The model's functional block is composed of a place cell (PC) connected with a local inhibitory cell (IC) which is modulated by the population theta rhythm. Both cells receive excitatory inputs from the entorhinal cortex (EC). These inputs are both theta modulated and space modulated. The dynamics of the two neuron types are described by integrate-and-fire models with conductance synapses, and the EC inputs are described using non-homogeneous Poisson processes. Phase precession in our model is caused by increased drive to specific PC/IC pairs when the animal is in their place field. The excitation increases the IC's firing rate, and this modulates the PC's firing rate such that both cells precess relative to theta. Our model implies that phase coding in place cells may not be independent from rate coding. The absence of restrictive connectivity constraints in this model predicts the generation of phase precession in any network with similar architecture and subject to a clocking rhythm, independently of the involvement in spatial tasks.

  17. Feasibility Study of Moderately Accelerated Intensity-Modulated Radiotherapy Plus Concurrent Weekly Cisplatin After Induction Chemotherapy in Locally Advanced Head-and Neck Cancer

    International Nuclear Information System (INIS)

    Morganti, Alessio G.; Mignogna, Samantha; Deodato, Francesco; Massaccesi, Mariangela; Cilla, Savino; Calista, Franco; Serafini, Giovanni; Digesu, Cinzia; Macchia, Gabriella; Picardi, Vincenzo; Caravatta, Luciana; Di Lullo, Liberato; Giglio, Gianfranco; Sallustio, Giuseppina; Piermattei, Angelo

    2011-01-01

    Purpose: To evaluate the feasibility and efficacy of moderately accelerated intensity-modulated radiation therapy (IMRT) along with weekly cisplatin, after induction chemotherapy, in patients with locally advanced unresectable head and neck cancer (HNC). Methods and Materials: Patients with Stage III or IV locally advanced HNC, without progressive disease after three courses of induction chemotherapy, received concurrent chemo-IMRT (weekly cisplatin 30 mg/m 2 plus simultaneous integrated boost IMRT). A total of 67.5 Gy in 30 fractions were delivered to primary tumor and involved nodes, 60 Gy in 30 fractions to high-risk nodal areas, and 55.5 Gy in 30 fractions to low-risk nodal areas. Results: In all, 36 patients (median age, 56 years) with International Union Against Cancer (UICC) Stage III (n = 5) and IV (n = 31) were included. Of the 36 patients, 17 had received CF (cisplatin and 5-fluorouracil (CF) and 19 had received docetaxel cisplatin and 5-fluorouracil (DCF). During concurrent chemoradiation, 11 of 36 patients (30.5%) experienced Grade III mucositis (CF, 47%; DCF, 15%; p < 0.04). Grade III pharyngeal-esophageal toxicity was observed in 5 of 19 patients (26.3%; CF, 0.0%; DCF, 26.3%; p = 0.02). Two patients died of complications (5.5%). After chemoradiation, the complete response rate was 63.8%. Two-year local control was 88.7%. Two-year progression free survival and overall survival were 74.5% and 60.9%, respectively. Conclusions: In our experience, a moderately accelerated chemo-IMRT was feasible after induction chemotherapy. However, a noteworthy early death rate of 5.5% was observed. Intensive supportive care strategies should be defined to better manage radiation-induced toxic effects. Longer follow-up is required to determine the incidence of late radiation toxicities and tumor control rates.

  18. COROTATING INTERACTION REGION ASSOCIATED SUPRATHERMAL HELIUM ION ENHANCEMENTS AT 1 AU: EVIDENCE FOR LOCAL ACCELERATION AT THE COMPRESSION REGION TRAILING EDGE

    International Nuclear Information System (INIS)

    Ebert, R. W.; Dayeh, M. A.; Desai, M. I.; Mason, G. M.

    2012-01-01

    We examined the temporal profiles and peak intensities for 73 corotating interaction region (CIR)-associated suprathermal (∼0.1-8 MeV nucleon –1 ) helium (He) ion enhancements identified at STEREO-A, STEREO-B, and/or Advanced Composition Explorer between 2007 and 2010. We found that in most events the peak He intensity times were well organized by the CIR compression region trailing edge, regardless of whether or not a reverse shock was present. Out of these events, 19% had their 0.193 MeV nucleon –1 He intensities peak within 1 hr and 50% within 4.75 hr of the CIR trailing edge, the distribution having a 1σ value of 7.3 hr. Events with a 0.193 MeV nucleon –1 He intensity peak time within 1σ of the CIR trailing edge showed a positive correlation between the ∼0.1 and 0.8 MeV nucleon –1 He peak intensities and magnetic compression ratios in events both with and without a reverse shock. The peak intensities in all other events showed little to moderate correlation between these parameters. Our results provide evidence that some fraction of the CIR-associated –1 He intensity enhancements observed at 1 AU are locally driven. We suggest an extended source for the CIR-associated energetic particles observed at 1 AU where the –1 ions are accelerated locally at or near the CIR trailing edge, the intensities being proportional to the local compression ratio strength, while the >MeV particles are likely accelerated at CIR-driven shocks beyond Earth orbit.

  19. Angular Acceleration without Torque?

    Science.gov (United States)

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  20. Feasibility and efficacy of accelerated weekly concomitant boost postoperative radiation therapy combined with concomitant chemotherapy in patients with locally advanced head and neck cancer.

    Science.gov (United States)

    Pehlivan, Berrin; Luthi, Francois; Matzinger, Oscar; Betz, Michael; Dragusanu, Daniela; Bulling, Shelley; Bron, Luc; Pasche, Philippe; Seelentag, Walter; Mirimanoff, René O; Zouhair, Abderrahim; Ozsahin, Mahmut

    2009-05-01

    The aim of this study was to assess feasibility and efficacy of weekly concomitant boost accelerated postoperative radiation therapy (PORT) with concomitant chemotherapy (CT) in patients with locally advanced head and neck cancer (LAHNC). Conformal or intensity-modulated 66-Gy RT was performed in 5.5 weeks in 40 patients. Cisplatin was given at days 1, 22, and 43. Median follow-up was 36 months. Grade 3 mucositis, dysphagia, and erythema was observed in ten (25%), nine (23%), and six (13%) patients, respectively. Grade 3 or more anemia was observed in two (6%) patients, and leukopenia in five (13%) patients. No grade 3 or 4 thrombocytopenia was observed. Grade 3 nephrotoxicity was observed in one patient (3%). No treatment-related mortality was observed. Grade 2 or more xerostomia and edema were observed in ten (25%) and one (3%) patient, respectively. Locoregional relapse occurred in eight patients, and seven patients developed distant metastases. Median time to locoregional relapse was 6 months. Three-year overall, disease-free survival, and locoregional control rates were 63%, 62%, and 81%, respectively. Multivariate analysis revealed that the only prognostic factor was nodal status. Reducing overall treatment time using accelerated PORT/CT by weekly concomitant boost (six fractions per week) combined with concomitant cisplatin CT is easily feasible with acceptable morbidity.

  1. Mapping the Information Trace in Local Field Potentials by a Computational Method of Two-Dimensional Time-Shifting Synchronization Likelihood Based on Graphic Processing Unit Acceleration.

    Science.gov (United States)

    Zhao, Zi-Fang; Li, Xue-Zhu; Wan, You

    2017-12-01

    The local field potential (LFP) is a signal reflecting the electrical activity of neurons surrounding the electrode tip. Synchronization between LFP signals provides important details about how neural networks are organized. Synchronization between two distant brain regions is hard to detect using linear synchronization algorithms like correlation and coherence. Synchronization likelihood (SL) is a non-linear synchronization-detecting algorithm widely used in studies of neural signals from two distant brain areas. One drawback of non-linear algorithms is the heavy computational burden. In the present study, we proposed a graphic processing unit (GPU)-accelerated implementation of an SL algorithm with optional 2-dimensional time-shifting. We tested the algorithm with both artificial data and raw LFP data. The results showed that this method revealed detailed information from original data with the synchronization values of two temporal axes, delay time and onset time, and thus can be used to reconstruct the temporal structure of a neural network. Our results suggest that this GPU-accelerated method can be extended to other algorithms for processing time-series signals (like EEG and fMRI) using similar recording techniques.

  2. Pulsed electromagnetic acceleration

    Science.gov (United States)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1973-01-01

    Direct measurements of the power deposited in the anode of a multimegawatt MPD accelerator using thermocouples attached to a thin shell anode reveal a dramatic decrease in the fractional anode power from 50% at 200 KW input power to less than 10% at 20 MW power. The corresponding local power flux peak at a value of 10,000 W/sq cm at the lip of the anode exhaust orifice, a distribution traced to a corresponding peak in the local current density at the anode. A comparison of voltage-current characteristics and spectral photographs of the MPD discharge using quartz, boron nitride and plexiglas insulators with various mass injection configurations led to the identification of different voltage modes and regions of ablation free operation. The technique of piezoelectric impact pressure measurement in the MPD exhaust flow was refined to account for the effects due to probe yaw angle.

  3. Application of the multicriterion optimization techniques and hierarchy of computational models to the research of ion acceleration due to laser-plasma interaction

    Science.gov (United States)

    Inovenkov, I. N.; Echkina, E. Yu.; Nefedov, V. V.; Ponomarenko, L. S.

    2017-12-01

    In this paper we discuss how a particles-in-cell computation code can be combined with methods of multicriterion optimization (in particular the Pareto optimal solutions of the multicriterion optimization problem) and a hierarchy of computational models approach to create an efficient tool for solving a wide array of problems related to the laser-plasma interaction. In case of the computational experiment the multicriterion optimization can be applied as follows: the researcher defines the objectives of the experiment - some computable scalar values (i.e. high kinetic energy of the ions leaving the domain, least possible number of electrons leaving domain in the given direction, etc). After that the parameters of the experiment which can be varied to achieve these objectives and the constrains on these parameters are chosen (e.g. amplitude and wave-length of the laser radiation, dimensions of the plasma slab(s)). The Pareto optimality of the vector of the parameters can be seen as this: x 0 is Pareto optimal if there exists no vector which would improve some criterion without causing a simultaneous degradation in at least one other criterion. These efficient set of parameter and constrains can be selected based on the preliminary calculations in the simplified models (one or two-dimensional) either analytical or numerical. The multistage computation of the Pareto set radically reduces the number of variants which are to be evaluated to achieve the given accuracy. During the final stage we further improve the results by recomputing some of the optimal variants on the finer grids, with more particles and/or in the frame of a more detailed model. As an example we have considered the ion acceleration caused by interaction of very intense and ultra-short laser pulses with plasmas and have calculated the optimal set of experiment parameters for optimizing number and average energy of high energy ions leaving the domain in the given direction and minimizing the expulsion

  4. The influence of quantitative tumor volume measurements on local control in advanced head and neck cancer using concomitant boost accelerated superfractionated irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Christopher R; Khandelwal, Shiv R; Schmidt-Ullrich, Rupert K; Ravalese, Joseph; Wazer, David E

    1995-06-15

    Purpose: Current methods to clinically define head and neck tumor bulk are qualitative and imprecise. Although the American Joint Committee on Cancer (AJCC) staging system is important for this purpose, limitations exist. This study will investigate the prognostic value of computed tomography (CT) derived tumor volume measurements in comparison to AJCC stage and other significant variables. Materials and Methods: Seventy-six patients with advanced head and neck squamous cell carcinoma were treated with concomitant boost accelerated superfractionated irradiation. Doses ranged from 68.4-73.8 Gy (median 70.2 Gy). Good quality pretherapy CT scans were available in 51 patients. Total tumor volume (TTV) estimates were derived from these scans using digital integration of primary tumor and metastatic lymphadenopathy. Actuarial and multivariate statistical techniques were applied to analyze local control. Results: Thirty-six-month local control was 63%. TTV ranged from 5-196 cm{sup 3} (median 35 cm{sup 3}) for all cases, 5-142 cm{sup 3} (median 17 cm{sup 3}) for those controlled, and 16-196 cm{sup 3} (median 47 cm{sup 3}) for local failures. There was a significant increase in failures above 35 cm{sup 3}. Univariate analysis found that TTV, T-stage, N-stage, and primary site were each significant prognostic variables. Local control for TTV {<=}35 cm{sup 3} was 92% at 36 months vs. 34% for TTV >35 cm{sup 3} (p = 0.0001). Multivariate analysis, however, found that TTV, primary site, and sex were important as independent variables; T and N stage were not independently significant unless TTV was removed from the model. Conclusions: This study demonstrates the prognostic significance of TTV in advanced carcinoma of the head and neck. This variable appears to be a more predictive than AJCC clinical stage. Quantitative tumor volume measurements may prove to be a useful parameter in future analyses of head and neck cancer.

  5. Effects of Shock and Turbulence Properties on Electron Acceleration

    Science.gov (United States)

    Qin, G.; Kong, F.-J.; Zhang, L.-H.

    2018-06-01

    Using test particle simulations, we study electron acceleration at collisionless shocks with a two-component model turbulent magnetic field with slab component including dissipation range. We investigate the importance of the shock-normal angle θ Bn, magnetic turbulence level {(b/{B}0)}2, and shock thickness on the acceleration efficiency of electrons. It is shown that at perpendicular shocks the electron acceleration efficiency is enhanced with the decrease of {(b/{B}0)}2, and at {(b/{B}0)}2=0.01 the acceleration becomes significant due to a strong drift electric field with long time particles staying near the shock front for shock drift acceleration (SDA). In addition, at parallel shocks the electron acceleration efficiency is increasing with the increase of {(b/{B}0)}2, and at {(b/{B}0)}2=10.0 the acceleration is very strong due to sufficient pitch-angle scattering for first-order Fermi acceleration, as well as due to the large local component of the magnetic field perpendicular to the shock-normal angle for SDA. On the other hand, the high perpendicular shock acceleration with {(b/{B}0)}2=0.01 is stronger than the high parallel shock acceleration with {(b/{B}0)}2=10.0, the reason might be the assumption that SDA is more efficient than first-order Fermi acceleration. Furthermore, for oblique shocks, the acceleration efficiency is small no matter whether the turbulence level is low or high. Moreover, for the effect of shock thickness on electron acceleration at perpendicular shocks, we show that there exists the bendover thickness, L diff,b. The acceleration efficiency does not noticeably change if the shock thickness is much smaller than L diff,b. However, if the shock thickness is much larger than L diff,b, the acceleration efficiency starts to drop abruptly.

  6. Stability of superconducting Rutherford cables for accelerator magnets

    NARCIS (Netherlands)

    Willering, G.P.

    2009-01-01

    The stability of superconducting magnets has a high priority for particle accelerators, since the operational time and operational collision energy depend strongly on it. Local heat dissipation due to beam loss and conductor movement is inevitable, causing local hot spots in the conductor, possibly

  7. Application of local approach to quantitative prediction of degradation in fracture toughness of steels due to pre-straining and irradiation

    International Nuclear Information System (INIS)

    Miyata, T.; Tagawa, T.

    1996-01-01

    Degradation of cleavage fracture toughness for low carbon steels due to pre-straining and irradiation was investigated on the basis of the local fracture criterion approach. Formulation of cleavage fracture toughness through the statistical modelling proposed by BEREMIN has been simplified by the present authors to the expression involving yield stress and cleavage fracture stress of materials. A few percent pre-strain induced by cold rolling deteriorates significantly the cleavage fracture toughness. Ductile-brittle transition temperature is increased to more than 70 C higher by 8% straining in 500 MPa class high strength steel. Quantitative prediction of degradation has been successfully examined through the formulation of the cleavage fracture toughness. Analytical and experimental results indicate that degradation in toughness is caused by the increase of flow stress in pre-strained materials. Quantitative prediction of degradation of toughness due to irradiation has been also examined for the past experiments on the basis of the local fracture criterion approach. Analytical prediction from variance of yield stress by irradiation is well consistent with the experimental results. (orig.)

  8. Extraordinary improvement of gas-sensing performances in SnO2 nanofibers due to creation of local p-n heterojunctions by loading reduced graphene oxide nanosheets.

    Science.gov (United States)

    Lee, Jae-Hyoung; Katoch, Akash; Choi, Sun-Woo; Kim, Jae-Hun; Kim, Hyoun Woo; Kim, Sang Sub

    2015-02-11

    We propose a novel approach to improve the gas-sensing properties of n-type nanofibers (NFs) that involves creation of local p-n heterojunctions with p-type reduced graphene oxide (RGO) nanosheets (NSs). This work investigates the sensing behaviors of n-SnO2 NFs loaded with p-RGO NSs as a model system. n-SnO2 NFs demonstrated greatly improved gas-sensing performances when loaded with an optimized amount of p-RGO NSs. Loading an optimized amount of RGOs resulted in a 20-fold higher sensor response than that of pristine SnO2 NFs. The sensing mechanism of monolithic SnO2 NFs is based on the joint effects of modulation of the potential barrier at nanograin boundaries and radial modulation of the electron-depletion layer. In addition to the sensing mechanisms described above, enhanced sensing was obtained for p-RGO NS-loaded SnO2 NFs due to creation of local p-n heterojunctions, which not only provided a potential barrier, but also functioned as a local electron absorption reservoir. These mechanisms markedly increased the resistance of SnO2 NFs, and were the origin of intensified resistance modulation during interaction of analyte gases with preadsorbed oxygen species or with the surfaces and grain boundaries of NFs. The approach used in this work can be used to fabricate sensitive gas sensors based on n-type NFs.

  9. Abdominal intra-compartment syndrome - a non-hydraulic model of abdominal compartment syndrome due to post-hepatectomy hemorrhage in a man with a localized frozen abdomen due to extensive adhesions: a case report.

    Science.gov (United States)

    Bressan, Alexsander K; Kirkpatrick, Andrew W; Ball, Chad G

    2016-09-15

    Postoperative hemorrhage is a significant cause of morbidity and mortality following liver resection. It typically presents early within the postoperative period, and conservative management is possible in the majority of cases. We present a case of late post-hepatectomy hemorrhage associated with overt abdominal compartment syndrome resulting from a localized functional compartment within the abdomen. A 68-year-old white man was readmitted with sudden onset of upper abdominal pain, vomiting, and hemodynamic instability 8 days after an uneventful hepatic resection for metachronous colon cancer metastasis. A frozen abdomen with adhesions due to complicated previous abdominal surgeries was encountered at the first intervention, but the surgery itself and initial recovery were otherwise unremarkable. Prompt response to fluid resuscitation at admission was followed by a computed tomography of his abdomen that revealed active arterial hemorrhage in the liver resection site and hemoperitoneum (estimated volume abdominal compartment syndrome. Surgical exploration confirmed a small volume of ascites and blood clots (1.2 L) under significant pressure in his supramesocolic region, restricted by his frozen lower abdomen, which we evacuated. Dramatic improvement in his ventilatory pressure was immediate. His abdomen was left open and a negative pressure device was placed for temporary abdominal closure. The fascia was formally closed after 48 hours. He was discharged home at postoperative day 6. Intra-abdominal pressure and radiologic findings of intra-abdominal hemorrhage should be carefully interpreted in patients with extensive intra-abdominal adhesions. A high index of suspicion and detailed understanding of abdominal compartment mechanics are paramount for the timely diagnosis of abdominal compartment syndrome in these patients. Clinicians should be aware that abnormal anatomy (such as adhesions) coupled with localized pathophysiology (such as hemorrhage) can create a so

  10. Hypofractionated Accelerated Radiotherapy Using Concomitant Intensity-Modulated Radiotherapy Boost Technique for Localized High-Risk Prostate Cancer: Acute Toxicity Results

    International Nuclear Information System (INIS)

    Lim, Tee S.; Cheung, Patrick; Loblaw, D. Andrew; Morton, Gerard; Sixel, Katharina E.; Pang, Geordi; Basran, Parminder; Zhang Liying; Tirona, Romeo; Szumacher, Ewa; Danjoux, Cyril; Choo, Richard; Thomas, Gillian

    2008-01-01

    Purpose: To evaluate the acute toxicities of hypofractionated accelerated radiotherapy (RT) using a concomitant intensity-modulated RT boost in conjunction with elective pelvic nodal irradiation for high-risk prostate cancer. Methods and Materials: This report focused on 66 patients entered into this prospective Phase I study. The eligible patients had clinically localized prostate cancer with at least one of the following high-risk features (Stage T3, Gleason score ≥8, or prostate-specific antigen level >20 ng/mL). Patients were treated with 45 Gy in 25 fractions to the pelvic lymph nodes using a conventional four-field technique. A concomitant intensity-modulated radiotherapy boost of 22.5 Gy in 25 fractions was delivered to the prostate. Thus, the prostate received 67.5 Gy in 25 fractions within 5 weeks. Next, the patients underwent 3 years of adjuvant androgen ablative therapy. Acute toxicities were assessed using the Common Terminology Criteria for Adverse Events, version 3.0, weekly during treatment and at 3 months after RT. Results: The median patient age was 71 years. The median pretreatment prostate-specific antigen level and Gleason score was 18.7 ng/L and 8, respectively. Grade 1-2 genitourinary and gastrointestinal toxicities were common during RT but most had settled at 3 months after treatment. Only 5 patients had acute Grade 3 genitourinary toxicity, in the form of urinary incontinence (n = 1), urinary frequency/urgency (n = 3), and urinary retention (n = 1). None of the patients developed Grade 3 or greater gastrointestinal or Grade 4 or greater genitourinary toxicity. Conclusion: The results of the present study have indicated that hypofractionated accelerated RT with a concomitant intensity-modulated RT boost and pelvic nodal irradiation is feasible with acceptable acute toxicity

  11. A meta-analysis of hyperfractionated and accelerated radiotherapy and combined chemotherapy and radiotherapy regimens in unresected locally advanced squamous cell carcinoma of the head and neck

    International Nuclear Information System (INIS)

    Budach, W; Hehr, T; Budach, V; Belka, C; Dietz, K

    2006-01-01

    Former meta-analyses have shown a survival benefit for the addition of chemotherapy (CHX) to radiotherapy (RT) and to some extent also for the use of hyperfractionated radiation therapy (HFRT) and accelerated radiation therapy (AFRT) in locally advanced squamous cell carcinoma (SCC) of the head and neck. However, the publication of new studies and the fact that many older studies that were included in these former meta-analyses used obsolete radiation doses, CHX schedules or study designs prompted us to carry out a new analysis using strict inclusion criteria. Randomised trials testing curatively intended RT (≥60 Gy in >4 weeks/>50 Gy in <4 weeks) on SCC of the oral cavity, oropharynx, hypopharynx, and larynx published as full paper or in abstract form between 1975 and 2003 were eligible. Trials comparing RT alone with concurrent or alternating chemoradiation (5-fluorouracil (5-FU), cisplatin, carboplatin, mitomycin C) were analyzed according to the employed radiation schedule and the used CHX regimen. Studies comparing conventionally fractionated radiotherapy (CFRT) with either HFRT or AFRT without CHX were separately examined. End point of the meta-analysis was overall survival. Thirty-two trials with a total of 10 225 patients were included into the meta-analysis. An overall survival benefit of 12.0 months was observed for the addition of simultaneous CHX to either CFRT or HFRT/AFRT (p < 0.001). Separate analyses by cytostatic drug indicate a prolongation of survival of 24.0 months, 16.8 months, 6.7 months, and 4.0 months, respectively, for the simultaneous administration of 5-FU, cisplatin-based, carboplatin-based, and mitomycin C-based CHX to RT (each p < 0.01). Whereas no significant gain in overall survival was observed for AFRT in comparison to CFRT, a substantial prolongation of median survival (14.2 months, p < 0.001) was seen for HFRT compared to CFRT (both without CHX). RT combined with simultaneous 5-FU, cisplatin, carboplatin, and mitomycin C as

  12. DART-bid: dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily. High local control in early stage (I/II) non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Zehentmayr, Franz; Wurstbauer, Karl; Deutschmann, Heinz; Sedlmayer, Felix; Fussl, Christoph; Kopp, Peter; Dagn, Karin; Fastner, Gerd; Porsch, Peter; Studnicka, Michael

    2015-01-01

    While surgery is considered standard of care for early stage (I/II), non-small-cell lung cancer (NSCLC), radiotherapy is a widely accepted alternative for medically unfit patients or those who refuse surgery. International guidelines recommend several treatment options, comprising stereotactic body radiation therapy (SBRT) for small tumors, conventional radiotherapy ≥ 60 Gy for larger sized especially centrally located lesions or continuous hyperfractionated accelerated RT (CHART). This study presents clinical outcome and toxicity for patients treated with a dose-differentiated accelerated schedule using 1.8 Gy bid (DART-bid). Between April 2002 and December 2010, 54 patients (median age 71 years, median Karnofsky performance score 70 %) were treated for early stage NSCLC. Total doses were applied according to tumor diameter: 73.8 Gy for 6 cm. The median follow-up was 28.5 months (range 2-108 months); actuarial local control (LC) at 2 and 3 years was 88 %, while regional control was 100 %. There were 10 patients (19 %) who died of the tumor, and 18 patients (33 %) died due to cardiovascular or pulmonary causes. A total of 11 patients (20 %) died intercurrently without evidence of progression or treatment-related toxicity at the last follow-up, while 15 patients (28 %) are alive. Acute esophagitis ≤ grade 2 occurred in 7 cases, 2 patients developed grade 2 chronic pulmonary fibrosis. DART-bid yields high LC without significant toxicity. For centrally located and/or large (> 5 cm) early stage tumors, where SBRT is not feasible, this method might serve as radiotherapeutic alternative to present treatment recommendations, with the need of confirmation in larger cohorts. (orig.) [de

  13. Can Accelerators Accelerate Learning?

    International Nuclear Information System (INIS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-01-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ)[1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  14. Can Accelerators Accelerate Learning?

    Science.gov (United States)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  15. Plasma accelerators

    International Nuclear Information System (INIS)

    Bingham, R.; Angelis, U. de; Johnston, T.W.

    1991-01-01

    Recently attention has focused on charged particle acceleration in a plasma by a fast, large amplitude, longitudinal electron plasma wave. The plasma beat wave and plasma wakefield accelerators are two efficient ways of producing ultra-high accelerating gradients. Starting with the plasma beat wave accelerator (PBWA) and laser wakefield accelerator (LWFA) schemes and the plasma wakefield accelerator (PWFA) steady progress has been made in theory, simulations and experiments. Computations are presented for the study of LWFA. (author)

  16. Linear Accelerators

    International Nuclear Information System (INIS)

    Vretenar, M

    2014-01-01

    The main features of radio-frequency linear accelerators are introduced, reviewing the different types of accelerating structures and presenting the main characteristics aspects of linac beam dynamics

  17. Assessment of external and internal doses due to farming in high background radiation areas in old tin mining localities in Jos-plateau, Nigeria

    International Nuclear Information System (INIS)

    Jibiri, N.N.; Farai, I.P.; Alausa, S.K.

    2009-01-01

    Farming on soils situated in high background radiation areas can result to enhanced radiation exposure scenarios and pathways to humans. To assess the likely levels of exposures, farm soil samples were collected from different farmlands in three old tin mining localities (Bitsichi, Bukuru and Ropp) in Jos Plateau Nigeria, known for high radiations. The soil samples were analyzed for the activity concentrations of 226 Ra, 232 Th and 40 K, using gamma-ray spectroscopy. The outdoor annual effective dose rates were calculated using the activity concentrations of the radionuclides and were found to vary from 0.07 mSv to 2.02 mSv across the three localities. Considering dust generation from soil tillage and inadvertent ingestion of soil particles, the likely internal radiation hazards were estimated using conservative dust and soil loading factors. The total average annual effective dose rates due to 226 Ra and 232 Th that could result from dust inhalation and ingestion of soil particles were 16.9 μSv, 8.1 μSv and 8.8 μSv, respectively for Bitsichi, Bukuru and Ropp. Though these values are about 5% the outdoor exposures to the farmers in those farms and greater than 1 μSv y-1, from the point of view of radiation protection and risk, they are significant. It suffices to say, therefore, that the results of this study will create the possibility of the importance to evaluate the health risk among the farming population and workplace environments which often is not covered by regulations concerning health protection. (author)

  18. Accelerator Service

    International Nuclear Information System (INIS)

    Champelovier, Y.; Ferrari, M.; Gardon, A.; Hadinger, G.; Martin, J.; Plantier, A.

    1998-01-01

    Since the cessation of the operation of hydrogen cluster accelerator in July 1996, four electrostatic accelerators were in operation and used by the peri-nuclear teams working in multidisciplinary collaborations. These are the 4 MV Van de Graaff accelerator, 2,5 MV Van de Graaff accelerator, 400 kV ion implanter as well as the 120 kV isotope separator

  19. A phase I study of dose-escalated chemoradiation with accelerated intensity modulated radiotherapy in locally advanced head and neck cancer

    International Nuclear Information System (INIS)

    Guerrero Urbano, Teresa; Clark, Catharine H.; Hansen, Vibeke N.; Adams, Elizabeth J.; A'Hern, Roger; Miles, Elizabeth A.; McNair, Helen; Bidmead, Margaret; Warrington, Alan P.; Dearnaley, David P.; Harrington, Kevin J.; Nutting, Christopher M.

    2007-01-01

    Background and purpose: Intensity modulated radiotherapy (IMRT) allows the delivery of higher and more homogeneous radiation dose to head and neck tumours. This study aims to determine the safety of dose-escalated chemo-IMRT for larynx preservation in locally advanced head and neck cancer. Methods: Patients with T2-4, N1-3, M0 squamous cell carcinoma of the larynx or hypopharynx were treated with a simultaneous-boost IMRT. Two radiation dose levels (DL) were tested: In DL 1, 63 Gy/28F was delivered to primary tumour and involved nodes and 51.8 Gy/28F to elective nodes. In DL 2, the doses were 67.2 Gy/28F and 56 Gy/28F, respectively, representing a 9% dose escalation for the primary. All patients received 2 cycles of neoadjuvant cisplatin and 5-fluorouracil, and concomitant cisplatin. Acute (NCICTCv.2.0) and late toxicity (RTOG and modified LENTSOM) were collected. Results: Thirty patients were entered, 15 in each dose level. All patients completed the treatment schedule. In DL 1, the incidences of acute G3 toxicities were 27% (pain), 20% (radiation dermatitis), 0% (xerostomia) and 67% required gastrostomy tubes. For DL 2 the corresponding incidences were 40%, 20%, 7%, and 87%. G3 dysphagia and pain persisted longer in DL 2. With regard to mucositis, a prolonged healing time for DL 2 was found, with prevalence of G2 of 58% in week 10. No acute grade 4 toxicity was observed. At 6 months, 1 patient in DL 2 had G3 late toxicity (dysphagia). No dose limiting toxicity was found. Complete response rates were 80% in DL 1, and 87% in DL 2. Conclusion: Moderately accelerated chemo-IMRT is safe and feasible with good compliance and acceptable acute toxicity. Dose escalation was possible without a significant difference in acute toxicity. Longer follow-up is required to determine the incidence of late radiation toxicities, and tumour control rates

  20. Liver acquisition with acceleration volume acquisition gadolinium-enhanced magnetic resonance combined with T2 sequences in the diagnosis of local recurrence of rectal cancer.

    Science.gov (United States)

    Cao, Wuteng; Li, Fangqian; Gong, Jiaying; Liu, Dechao; Deng, Yanhong; Kang, Liang; Zhou, Zhiyang

    2016-11-22

    To investigate the efficacy of liver acquisition with acceleration volume acquisition (LAVA) gadolinium-enhanced magnetic resonance (MR) sequences and to assess its added accuracy in diagnosing local recurrence (LR) of rectal cancer with conventional T2-weighted fast spin echo (FSE) sequences. Pelvic MRI, including T2-weighted FSE sequences, gadolinium-enhanced sequences of LAVA and T1-weighted FSE with fat suppression, was performed on 225 patients with postoperative rectal cancer. Two readers evaluated the presence of LR according to "T2" (T2 sequences only), "T2 + LAVA-Gad" (LAVA and T2 imaging), and "T2 + T1-fs-Gad" (T1 fat suppression-enhanced sequence with T2 images). To evaluate diagnostic efficiency, imaging quality with LAVA and T1-fs-Gad by subjective scores and the signal intensity (SI) ratio. In the result, the SI ratio of LAVA was significantly higher than that of T1-fs-Gad (p = 0.0001). The diagnostic efficiency of "T2 + LAVA-Gad" was better than that of "T2 + T1-fs-Gad" (p = 0.0016 for Reader 1, p = 0.0001 for Reader 2) and T2 imaging only (p = 0.0001 for Reader 1; p = 0.0001 for Reader 2). Therefore, LAVA gadolinium-enhanced MR increases the accuracy of diagnosis of LR from rectal cancer and could replace conventional T1 gadolinium-enhanced sequences in the postoperative pelvic follow-up of rectal cancer.

  1. 137Cs And 210Po Dose Assessment Due To Consumption Of Red Sea Coral Reef Fishes Collected From The Local Market (Sudan)

    International Nuclear Information System (INIS)

    Hassona, R. K.; Sam, A. K.; Sirelkhatim, D. A.; Osman, O. I.; Larosa, J.

    2004-01-01

    Assessment of Committed Effective Dose (CED) due to consumption of marine fishes (Red Sea area) was performed in 33 different marine fish samples collected from the local market at Port sudan and classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Activity concentrations of 210 Po and 137 Cs were determined and were found to range between 0.25 to 6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/Kg fresh w. for 210 Po and 0.1 to 0.46 (carnivores), 0.09 to 0.35 (omnivores) and 0.09 to 0.3 (herbivores) Bq/Kg fresh w. For 137 Cs which are several times lower than those of 210 Po. Appropriate conversion factors were used to derive the CED which was found to be 0.012, 0.01 and 0.01 (μ Sv/y) in carnivores, omnivores and herbivores, respectively, for 137 Cs, this contributes about 0.4% of the total dose. While for 210 Po, it was found to be 3.47, 4.81 and 4.14 (μ Sv/y) in carnivores, omnivores and herbivores, respectively which represents 99.6% of the total dose. The results of CED suggest that the dose received by Sudanese population from the consumption of marine fishes is rather small and the contribution of 137 Cs is negligible compared to 210 Po. (Authors)

  2. Local Control, Toxicity, and Cosmesis in Women >70 Years Enrolled in the American Society of Breast Surgeons Accelerated Partial Breast Irradiation Registry Trial

    International Nuclear Information System (INIS)

    Khan, Atif J.; Vicini, Frank A.; Beitsch, Peter; Goyal, Sharad; Kuerer, Henry M.; Keisch, Martin; Quiet, Coral; Zannis, Victor; Keleher, Angela; Snyder, Howard; Gittleman, Mark; Whitworth, Pat; Fine, Richard; Lyden, Maureen; Haffty, Bruce G.

    2012-01-01

    Purpose: The American Society of Breast Surgeons enrolled women in a registry trial to prospectively study patients treated with the MammoSite Radiation Therapy System breast brachytherapy device. The present report examined the outcomes in women aged >70 years enrolled in the trial. Methods and Materials: A total of 1,449 primary early stage breast cancers were treated in 1,440 women. Of these, 537 occurred in women >70 years old. Fisher’s exact test was performed to correlate age (≤70 vs. >70 years) with toxicity and with cosmesis. The association of age with local recurrence (LR) failure times was investigated by fitting a parametric model. Results: Older women were less likely to develop telangiectasias than younger women (7.9% vs. 12.4%, p = 0.0083). The incidence of other toxicities was similar. Cosmesis was good or excellent in 92% of the women >70 years old. No significant difference was found in LR as a function of age. The 5-year actuarial LR rate with invasive disease for the older vs. younger population was 2.79% and 2.92%, respectively (p = 0.5780). In women >70 years with hormone-sensitive tumors ≤2 cm who received hormonal therapy (n = 195), the 5-year actuarial rate of LR, overall survival, disease-free survival, and cause-specific survival was 2.06%, 89.3%, 87%, and 97.5%, respectively. These outcomes were similar in women who did not receive hormonal therapy. Women with small, estrogen receptor-negative disease had worse LR, overall survival, and disease-free survival compared with receptor-positive patients. Conclusions: Accelerated partial breast irradiation with the MammoSite radiation therapy system resulted in low toxicity and produced similar cosmesis and local control at 5 years in women >70 years compared with younger women. This treatment should be considered as an alternative to omitting adjuvant radiotherapy for older women with small-volume, early-stage breast cancer.

  3. Local Control, Toxicity, and Cosmesis in Women >70 Years Enrolled in the American Society of Breast Surgeons Accelerated Partial Breast Irradiation Registry Trial

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Atif J., E-mail: atif_khan@rwjuh.edu [Robert Wood Johnson University Hospital, Cancer Institute of New Jersey, New Brunswick, NJ (United States); Vicini, Frank A.; Beitsch, Peter [American Society of Breast Surgeons, Columbia, MD (United States); Goyal, Sharad [Robert Wood Johnson University Hospital, Cancer Institute of New Jersey, New Brunswick, NJ (United States); Kuerer, Henry M.; Keisch, Martin; Quiet, Coral; Zannis, Victor; Keleher, Angela; Snyder, Howard; Gittleman, Mark; Whitworth, Pat; Fine, Richard [American Society of Breast Surgeons, Columbia, MD (United States); Lyden, Maureen [BioStat International, Inc., Tampa, FL (United States); Haffty, Bruce G. [Robert Wood Johnson University Hospital, Cancer Institute of New Jersey, New Brunswick, NJ (United States); American Society of Breast Surgeons, Columbia, MD (United States)

    2012-10-01

    Purpose: The American Society of Breast Surgeons enrolled women in a registry trial to prospectively study patients treated with the MammoSite Radiation Therapy System breast brachytherapy device. The present report examined the outcomes in women aged >70 years enrolled in the trial. Methods and Materials: A total of 1,449 primary early stage breast cancers were treated in 1,440 women. Of these, 537 occurred in women >70 years old. Fisher's exact test was performed to correlate age ({<=}70 vs. >70 years) with toxicity and with cosmesis. The association of age with local recurrence (LR) failure times was investigated by fitting a parametric model. Results: Older women were less likely to develop telangiectasias than younger women (7.9% vs. 12.4%, p = 0.0083). The incidence of other toxicities was similar. Cosmesis was good or excellent in 92% of the women >70 years old. No significant difference was found in LR as a function of age. The 5-year actuarial LR rate with invasive disease for the older vs. younger population was 2.79% and 2.92%, respectively (p = 0.5780). In women >70 years with hormone-sensitive tumors {<=}2 cm who received hormonal therapy (n = 195), the 5-year actuarial rate of LR, overall survival, disease-free survival, and cause-specific survival was 2.06%, 89.3%, 87%, and 97.5%, respectively. These outcomes were similar in women who did not receive hormonal therapy. Women with small, estrogen receptor-negative disease had worse LR, overall survival, and disease-free survival compared with receptor-positive patients. Conclusions: Accelerated partial breast irradiation with the MammoSite radiation therapy system resulted in low toxicity and produced similar cosmesis and local control at 5 years in women >70 years compared with younger women. This treatment should be considered as an alternative to omitting adjuvant radiotherapy for older women with small-volume, early-stage breast cancer.

  4. Particle-accelerator decommissioning

    International Nuclear Information System (INIS)

    Opelka, J.H.; Mundis, R.L.; Marmer, G.J.; Peterson, J.M.; Siskind, B.; Kikta, M.J.

    1979-12-01

    Generic considerations involved in decommissioning particle accelerators are examined. There are presently several hundred accelerators operating in the United States that can produce material containing nonnegligible residual radioactivity. Residual radioactivity after final shutdown is generally short-lived induced activity and is localized in hot spots around the beam line. The decommissioning options addressed are mothballing, entombment, dismantlement with interim storage, and dismantlement with disposal. The recycle of components or entire accelerators following dismantlement is a definite possibility and has occurred in the past. Accelerator components can be recycled either immediately at accelerator shutdown or following a period of storage, depending on the nature of induced activation. Considerations of cost, radioactive waste, and radiological health are presented for four prototypic accelerators. Prototypes considered range from small accelerators having minimal amounts of radioactive mmaterial to a very large accelerator having massive components containing nonnegligible amounts of induced activation. Archival information on past decommissionings is presented, and recommendations concerning regulations and accelerator design that will aid in the decommissioning of an accelerator are given

  5. FFAGS for muon acceleration

    International Nuclear Information System (INIS)

    Berg, J. Scott; Kahn, Stephen; Palmer, Robert; Trbojevic, Dejan; Johnstone, Carol; Keil, Eberhard; Aiba, Masamitsu; Machida, Shinji; Mori, Yoshiharu; Ogitsu, Toru; Ohmori, Chihiro; Sessler, Andrew; Koscielniak, Shane

    2003-01-01

    Due to their finite lifetime, muons must be accelerated very rapidly. It is challenging to make the magnets ramp fast enough to accelerate in a synchrotron, and accelerating in a linac is very expensive. One can use a recirculating accelerator (like CEBAF), but one needs a different arc for each turn, and this limits the number of turns one can use to accelerate, and therefore requires significant amounts of RF to achieve the desired energy gain. An alternative method for muon acceleration is using a fixed field alternating gradient (FFAG) accelerator. Such an accelerator has a very large energy acceptance (a factor of two or three), allowing one to use the same arc with a magnetic field that is constant over time. Thus, one can in principle make as many turns as one can tolerate due to muon decay, therefore reducing the RF cost without increasing the arc cost. This paper reviews the current status of research into the design of FFAGs for muon acceleration. Several current designs are described and compared. General design considerations are also discussed

  6. Comparison of two dimensional and three dimensional radiotherapy treatment planning in locally advanced non-small cell lung cancer treated with continuous hyperfractionated accelerated radiotherapy weekend less

    International Nuclear Information System (INIS)

    Wilson, Elena M.; Joy Williams, Frances; Ethan Lyn, Basil; Aird, Edwin G.A.

    2005-01-01

    Background and purpose: Patients with inoperable non-small cell lung cancer being treated with continuous hyperfractionated accelerated radiotherapy weekend less (CHARTWEL) were planned and treated with a three dimensional (3D) conformal protocol and comparison made with two dimensional (2D) planning, as used previously, to compare past practice and methods. Patients and methods: Twenty-four patients were planned initially using 3D and then replanned using a 2D system. The 2D plans were transferred onto the 3D system and recalculated. Dose volume histograms could then be constructed of planning target volumes for phases 1 and 2 (PTV 1 and 2, respectively), lung and spinal cord for the 2D plans and compared with the 3D plans. Results: There was a significantly lower absolute dose to the isocentre with 2D compared to 3D planning with dose reductions of 3.9% for phase 1, 4.4% for phase 2 and 4.7% for those treated with a single phase. Maximum dose to spinal cord was greater in 17 of the 24 2D plans with a median dose reduction of 0.82 Gy for 3D (P=0.04). The percentage volume of whole lung receiving ≥20 Gy (V 20 ) was greater in 16 of the 24 2D plans with a median reduction in V 20 of 2.4% for 3D (P=0.03). Conclusions: A lower dose to tumour was obtained using 2D planning due to the method of dose calculation and spinal cord and lung doses were significantly higher

  7. Histopatologia da forma localizada de leishmaniose cutânea por Leishmania (Leishmania amazonensis Histopathology of the localized form of cutaneous leishmaniasis due to Leishmania (Leishmania amazonensis

    Directory of Open Access Journals (Sweden)

    Mário A. P. Moraes

    1994-10-01

    Full Text Available São descritas as alterações microscópicas presentes na forma localizada (ulcerada da Leishmaniose cutânea produzida por Leishmania (Leishmania amazonensis. Nesse tipo de manifestação, menos conhecido do que a forma anérgica ou difusa devida ao mesmo agente, as lesões são clinicamente idênticas às de leishmaniose cutânea causada por espécies outras de Leishmania, pertencentes ao subgênero Viannia. Na infecção localizada por L. (L. amazonensis, entretanto, há um aspecto peculiar, só recentemente conhecido, ou seja, cerca de 50% dos indivíduos atingidos não reagem ao teste de Montenegro. A principal característica histológica observada foi a acumulação na derme, quase sempre focal, de numerosos macrófagos contendo no citoplasma um grande vacúolo cheio de amastigotas. O quadro é semelhante ao da forma difusa, porém sem o aspecto histiocitomatóide, próprio da última. Afora esses grupos de macrófagos, vêem-se também, na forma localizada, muitas células mononucleares da inflamação, principalmente plasmócitos e macrófagos não parasitados. Os acúmulos de macrófagos com amastigotas, quando volumosos, podem sofrer necrose na parte central; os parasitos, contidos nas células, são destruídos com elas ou liberados, e sua eliminação através da úlcera deve contribuir para a cura do processo. Esse tipo de necrose nunca foi descrito em casos da forma difusa. Não houve grande diferença, no quadro histológico, entre pacientes Montenegro-negativos e positivos. Apenas em alguns casos, do grupo Montenegro-positivo, havia granulomas formados por histiócitos epitelióides sem parasitos. Quanto à persistência das células com parasitos nas lesões, observou-se que aos seis meses ou mais de evolução, em ambos os grupos, ainda estavam elas presentes. Tal achado não é comum na leishmaniose tegumentar por L. (V. braziliensis.The microscopic changes found in the localized form of the human cutaneous leishmaniasis due

  8. {sup 137}Cs and {sup 210}Po dose assessment due to consumption of red sea coral reef fishes collected from the local market (Sudan)

    Energy Technology Data Exchange (ETDEWEB)

    Hassona, R K; Sam, A K; Sirelkhatim, D A [Sudan Atomic Energy Commission, Khartoum (Sudan); Osman, O I [Chemistry Department, Faculty of Science, University of Khartoum, Khartoum (Sudan); Larosa, J [Marine Environment Laboratory, IAEA (Monaco)

    2004-12-15

    Assessment of committed effective dose (CED) due to consumption of marine fishes (Red Sea) was performed in 33 different marine fish samples collected from the local market at Port Sudan and classified according to their feeding habits into three categories: carnivores, herbivores and omnivores. Activity concentration of 2{sup 10P}o and 1{sup 37C}s were determined and were found to range between 0.25 to 6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/Kg fresh w. For {sup 210}Po and 0.1 to 0.46 (carnivores), 0.09 to 0.35 (omnivores) and 0.09 to 0.32 (herbivores) Bq/kg fresh w. For 1{sup 37C}s which are several times lower than those of 2{sup 10P}o. Appropriate conversion factors were used to derive the CED which was found to be 0.012, 0.01 and 0.01 ({mu}Sv/y) in carnivores, omnivores and herbivores, respectively for {sup 137}Cs this contributes about 0.4% of the total dose. While for {sup 210}Po, it was found to be 3.47, 4.81 and 4.14 ({mu}Sv/y) in carnivores, omnivores and herbivores, respectively which represents 99.6% of the total dose. The results of CED suggest that the dose received by Sudanese population from the consumption of marine fishes is rather small and the contribution of {sup 13}'7Cs is negligible compared to {sup 210}Po.(Author)

  9. 137Cs and 210Po dose assessment due to consumption of red sea coral reef fishes collected from the local market (Sudan)

    International Nuclear Information System (INIS)

    Hassona, R. K.; Sam, A. K.; Sirelkhatim, D. A.; Osman, O. I.; Larosa, J.

    2004-12-01

    Assessment of committed effective dose (CED) due to consumption of marine fishes (Red Sea) was performed in 33 different marine fish samples collected from the local market at Port Sudan and classified according to their feeding habits into three categories: carnivores, herbivores and omnivores. Activity concentration of 2 10P o and 1 37C s were determined and were found to range between 0.25 to 6.42 (carnivores), 0.7-5 (omnivores) and 1.5-3.8 (herbivores) Bq/Kg fresh w. For 210 Po and 0.1 to 0.46 (carnivores), 0.09 to 0.35 (omnivores) and 0.09 to 0.32 (herbivores) Bq/kg fresh w. For 1 37C s which are several times lower than those of 2 10P o. Appropriate conversion factors were used to derive the CED which was found to be 0.012, 0.01 and 0.01 (μSv/y) in carnivores, omnivores and herbivores, respectively for 137 Cs this contributes about 0.4% of the total dose. While for 210 Po, it was found to be 3.47, 4.81 and 4.14 (μSv/y) in carnivores, omnivores and herbivores, respectively which represents 99.6% of the total dose. The results of CED suggest that the dose received by Sudanese population from the consumption of marine fishes is rather small and the contribution of 13 '7Cs is negligible compared to 210 Po.(Author)

  10. Concurrent hyperfractionated accelerated radiotherapy with 5-FU and once weekly cisplatin in locally advanced head and neck cancer. The 10-year results of a prospective phase II trial

    Energy Technology Data Exchange (ETDEWEB)

    Budach, V.; Boehmer, D.; Badakhshi, H.; Jahn, U.; Stromberger, C. [Campus Virchow Klinikum, Charite Universitaetsmedizin Berlin, Department for Radiooncology, Clinic for Radiooncology, Berlin (Germany); Becker, E.T. [Charite Universitaetsmedizin, Department of Otorhinolaryngology, Berlin (Germany); Wernecke, K.D. [Sostana Statistics GmbH, Charite Universitaetsmedizin Berlin, Berlin (Germany)

    2014-03-15

    In this study, the acute toxicity and long-term outcome of a hyperfractionated accelerated chemoradiation regimen with cisplatin/5-fluorouracil (5-FU) in patients with locally advanced squamous cell carcinomas of head and neck were evaluated. From 2000-2002, 38 patients with stage III (5.3 %) and stage IV (94.7 %) head and neck cancer were enrolled in a phase II study. Patients received hyperfractionated-accelerated radiotherapy with 72 Gy in 15 fractions of 2 Gy followed by 1.4 Gy twice daily with concurrent, continuous infusion 5-FU of 600 mg/m{sup 2} on days 1-5 and 6 cycles of weekly cisplatin (30 mg/m{sup 2}). Acute toxicities (CTCAEv2.0), locoregional control (LRC), metastases-free (MFS), and overall survival (OS) were analyzed and exploratively compared with the ARO 95-06 trial. Median follow-up was 11.4 years (95 % CI 8.6-14.2) and mean dose 71.6 Gy. Of the patients, 82 % had 6 (n = 15) or 5 (n = 16) cycles of cisplatin, 5 and 2 patients received 4 and 3 cycles, respectively. Grade 3 anemia, leukopenia, and thrombocytopenia were observed in 15.8, 15.8, and 2.6 %, respectively. Grade 3 mucositis in 50 %, grade 3 and 4 dysphagia in 55 and 13 %. The 2-, 5-, and 10-year LRC was 65, 53.6, and 48.2 %, the MFS was 77.5, 66.7, and 57.2 % and the OS 59.6, 29.2, and 15 %, respectively. Chemoradiation with 5-FU and cisplatin seems feasible and superior in terms of LRC and OS to the ARO 95-06C-HART arm at 2 years. However, this did not persist at the 5- and 10-year follow-ups. (orig.) [German] Untersuchung der Akuttoxizitaet und des Langzeitueberlebens einer hyperfraktioniert-akzelerierten simultanen Radiochemotherapie mit Cisplatin/5-Fluorouracil (5-FU) bei Patienten mit lokal fortgeschrittenen Kopf-Hals-Tumoren. Von 2000 bis 2002 wurden 38 Patienten mit Plattenepithelkarzinomen der Kopf-Hals-Region im Stadium III (5,3 %) und IV (94,7 %) eingeschlossen. Es erfolgte eine simultane hyperfraktionierte akzelerierte Radiochemotherapie mit 72 Gy in 15 Fraktionen a 2 Gy

  11. Future accelerators (?)

    Energy Technology Data Exchange (ETDEWEB)

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  12. Plasma particle accelerators

    International Nuclear Information System (INIS)

    Dawson, J.M.

    1988-01-01

    The Superconducting Supercollider (SSC) will require an 87-kilometer accelerator ring to boost particles to 40 TeV. The SSC's size is due in part to the fact that its operating principle is the same one that has dominated accelerator design for 50 years: it guides particles by means of magnetic fields and propels them by strong electric fields. If one were to build an equally powerful but smaller accelerator, one would need to increase the strength of the guiding and propelling fields. Actually, however, conventional technology may not be able to provide significant increases in field strength. There are two reasons. First, the forces from magnetic fields are becoming greater than the structural forces that hold a magnetic material together; the magnets that produce these fields would themselves be torn apart. Second, the energy from electric fields is reaching the energies that bind electrons to atoms; it would tear electrons from nuclei in the accelerator's support structures. It is the electric field problem that plasma accelerators can overcome. Plasma particle accelerators are based on the principle that particles can be accelerated by the electric fields generated within a plasma. Because the plasma has already been ionized, plasma particle accelerators are not susceptible to electron dissociation. They can in theory sustain accelerating fields thousands of times stronger that conventional technologies. So far two methods for creating plasma waves for accelerators have been proposed and tested: the wakefield and the beat wave. Although promising electric fields have been produced, more research is necessary to determine whether plasma particle accelerators can compete with the existing accelerators. 7 figs

  13. Heavy ion medical accelerator, HIMAC

    International Nuclear Information System (INIS)

    Yamada, Satoru

    1993-01-01

    The heavy ion beam is undoutedly suitable for the cancer treatment. The supriority of the heavy ions over the conventional radiations including protons and neutrons comes mainly from physical characteristics of a heavy particle with multiple charges. A straggling angle due to a multiple Coulomb scattering process in a human body is small for heavy ions, and the small scattering angle results in a good dose localization in a transverse direction. An ionization ratio of the heavy ion beam makes a very sharp peak at the ends of their range. The height of the peak is higher for the heavier ions and shows excellent biomedical effects around Ne ions. In order to apply heavy ion beams to cancer treatment, Heavy Ion Medical Accelerator in Chiba (HIMAC) has been constructed at National Institute of Radiological Sciences. The accelerator complex consists of two ion sources, two successive linac tanks, a pair of synchrotron rings, a beam transport system and an irradiation system. An operation frequency is 100 MHz for two linacs, and the ion energy is 6.0 MeV/u at the output end of the linac. The other four experimental rooms are prepared for basic experiments. The synchrotron accelerates ions up to 800 MeV/u for a charge to mass ratio of 1/2. The long beam transport line provides two vertical beams in addition with two horizontal beams for the treatment. The three treatment rooms are prepared one of which is equipped with both horizontal and vertical beam lines. The whole facility will be open for all scientists who have interests in the heavy ion science as well as the biophysics. The conceptual design study of HIMAC started in 1984, and the construction of the accelerator complex was begun in March 1988. The beam acceleration tests of the injector system was successfully completed in March of this year, and tests of the whole system will be finished throughout this fyscal year. (author)

  14. Spacetime transformations from a uniformly accelerated frame

    International Nuclear Information System (INIS)

    Friedman, Yaakov; Scarr, Tzvi

    2013-01-01

    We use the generalized Fermi–Walker transport to construct a one-parameter family of inertial frames which are instantaneously comoving to a uniformly accelerated observer. We explain the connection between our approach and that of Mashhoon. We show that our solutions of uniformly accelerated motion have constant acceleration in the comoving frame. Assuming the weak hypothesis of locality, we obtain local spacetime transformations from a uniformly accelerated frame K′ to an inertial frame K. The spacetime transformations between two uniformly accelerated frames with the same acceleration are Lorentz. We compute the metric at an arbitrary point of a uniformly accelerated frame. (paper)

  15. SU-E-I-91: Reproducibility in Prescribed Dose in AEC CT Scans Due to Table Height, Patient Size, and Localizer Acquisition Order

    International Nuclear Information System (INIS)

    Winslow, J; Hurwitz, L; Christianson, O; Samei, E

    2014-01-01

    Purpose: In CT scanners, the automatic exposure control (AEC) tube current prescription depends on the acquired prescan localizer image(s). The purpose of this study was to quantify the effect that table height, patient size, and localizer acquisition order may have on the reproducibility in prescribed dose. Methods: Three phantoms were used for this study: the Mercury Phantom (comprises three tapered and four uniform regions of polyethylene 16, 23, 30, and 37 cm in diameter), acrylic sheets, and an adult anthropomorphic phantom. Phantoms were positioned per clinical protocol by our chief CT technologist or broader symmetry. Using a GE Discovery CT750HD scanner, a lateral (LAT) and posterior-anterior (PA) localizer was acquired for each phantom at different table heights. AEC scan acquisitions were prescribed for each combination of phantom, localizer orientation, and table height; the displayed volume CTDI was recorded for each. Results were analyzed versus table height. Results: For the two largest Mercury Phantom section scans based on the PA localizer, the percent change in volume CTDI from ideal were at least 20% lower and 35% greater for table heights 4 cm above and 4 cm below proper centering, respectively. For scans based on the LAT localizer, the percent change in volume CTDI from ideal were no greater than 12% different for 4 cm differences in table height. The properly centered PA and LAT localizer-based volume CTDI values were within 13% of each other. Conclusion: Since uncertainty in vertical patient positioning is inherently greater than lateral positioning and because the variability in dose exceeds any dose penalties incurred, the LAT localizer should be used to precisely and reproducibly deliver the intended amount of radiation prescribed by CT protocols. CT protocols can be adjusted to minimize the expected change in average patient dose

  16. DART-bid: dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily. High local control in early stage (I/II) non-small-cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zehentmayr, Franz; Wurstbauer, Karl; Deutschmann, Heinz; Sedlmayer, Felix [Landeskrankenhaus Salzburg, Univ.-Klinik fuer Radiotherapie und Radio-Onkologie, Univ.-Klinikum der Paracelsus Medizinischen Privatuniversitaet, Salzburg (Austria); Paracelsus Medizinische Privatuniversitaet, Institute for Research and Development of Advanced Radiation Technologies (radART), Salzburg (Austria); Fussl, Christoph; Kopp, Peter; Dagn, Karin; Fastner, Gerd [Landeskrankenhaus Salzburg, Univ.-Klinik fuer Radiotherapie und Radio-Onkologie, Univ.-Klinikum der Paracelsus Medizinischen Privatuniversitaet, Salzburg (Austria); Porsch, Peter; Studnicka, Michael [Landeskrankenhaus Salzburg, Univ.-Klinik fuer Pneumologie, Univ.-Klinikum der Paracelsus Medizinischen Privatuniversitaet, Salzburg (Austria)

    2014-09-23

    While surgery is considered standard of care for early stage (I/II), non-small-cell lung cancer (NSCLC), radiotherapy is a widely accepted alternative for medically unfit patients or those who refuse surgery. International guidelines recommend several treatment options, comprising stereotactic body radiation therapy (SBRT) for small tumors, conventional radiotherapy ≥ 60 Gy for larger sized especially centrally located lesions or continuous hyperfractionated accelerated RT (CHART). This study presents clinical outcome and toxicity for patients treated with a dose-differentiated accelerated schedule using 1.8 Gy bid (DART-bid). Between April 2002 and December 2010, 54 patients (median age 71 years, median Karnofsky performance score 70 %) were treated for early stage NSCLC. Total doses were applied according to tumor diameter: 73.8 Gy for < 2.5 cm, 79.2 Gy for 2.5-4.5 cm, 84.6 Gy for 4.5-6 cm, 90 Gy for > 6 cm. The median follow-up was 28.5 months (range 2-108 months); actuarial local control (LC) at 2 and 3 years was 88 %, while regional control was 100 %. There were 10 patients (19 %) who died of the tumor, and 18 patients (33 %) died due to cardiovascular or pulmonary causes. A total of 11 patients (20 %) died intercurrently without evidence of progression or treatment-related toxicity at the last follow-up, while 15 patients (28 %) are alive. Acute esophagitis ≤ grade 2 occurred in 7 cases, 2 patients developed grade 2 chronic pulmonary fibrosis. DART-bid yields high LC without significant toxicity. For centrally located and/or large (> 5 cm) early stage tumors, where SBRT is not feasible, this method might serve as radiotherapeutic alternative to present treatment recommendations, with the need of confirmation in larger cohorts. (orig.) [German] Die Standardbehandlung fuer nichtkleinzellige Bronchialkarzinome (NSCLC) im Stadium I/II ist die Operation, wobei Radiotherapie fuer Patienten, die nicht operabel sind oder die Operation ablehnen, als Alternative

  17. Aggressive simultaneous radiochemotherapy with cisplatin and paclitaxel in combination with accelerated hyperfractionated radiotherapy in locally advanced head and neck tumors. Results of a phase I-II trial

    Energy Technology Data Exchange (ETDEWEB)

    Kuhnt, T.; Pigorsch, S.; Pelz, T.; Haensgen, G.; Dunst, J. [Dept. of Radiotherapy, Martin Luther Univ., Halle (Germany); Becker, A. [Dept. of Radiotherapy, Martin Luther Univ., Halle (Germany); Dept. of Radiotherapy, Municipial Hospital, Dessau (Germany); Bloching, M.; Passmann, M. [Dept. of Head and Neck Surgery, Martin Luther Univ., Halle (Germany); Lotterer, E. [Dept. of Internal Medicine I, Martin Luther Univ., Halle (Germany)

    2003-10-01

    We have tested a very aggressive combination protocol with cisplatin and escalated paclitaxel in combination with accelerated hyperfractionated radiotherapy to assess the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), overall toxicity, and response rate. Patients and Methods: The trial recruited 24 patients (21 males, three females, mean age 57 years) treated at our department from 1998 through 2001. Irradiation was administered in daily doses of 2 Gy up to 30 Gy followed by 1.4 Gy twice daily up to 70.6 Gy to the primary tumor and involved nodes and 51 Gy to the clinically negative regional nodes. The chemotherapy schedule included cisplatin in a fixed dose of 20 mg/m{sup 2} on days 1-5 and 29-33 and paclitaxel at increasing dose levels of 20, 25, 30 mg/m{sup 2} twice weekly over the whole treatment time. Patients were recruited in cohorts of three to six, and the MTD was reached if two out of six patients in one cohort developed DLT. DLT was defined as any grade 4 toxicity or any grade 3 toxicity requiring treatment interruption or unplanned hospitalization or any grade 3 neurotoxicity. We recruited mainly patients with large tumors for this protocol; all patients were stage IV, and the mean tumor volume (primary + metastases) amounted to 72 {+-} 61 cm{sup 3}. The mean follow-up was 30 months (range 4-39 months). Results: One early death (peritonitis and sepsis a t day 10) occurred, and 23 patients were evaluable for acute toxicity and response. The MTD of paclitaxel was reached at the third dose level (30 mg/m{sup 2} paclitaxel twice weekly). The DLT was severe mucositis grade 3 (n = 1) and skin erythema grade 4 (n = 2). After determining the MTD, another 14 patients were treated at the recommended dose level of paclitaxel with 25 mg/m{sup 2} twice weekly. In summary, 13/23 patients (57%) developed grade 3 and 10/23 (43%) grade 2 mucositis. Two patients (9%) had grade 4, five (22%) grade 3, and 16 (69%) grade 2 dermatitis. One patient died at day 30

  18. Aggressive simultaneous radiochemotherapy with cisplatin and paclitaxel in combination with accelerated hyperfractionated radiotherapy in locally advanced head and neck tumors. Results of a phase I-II trial

    International Nuclear Information System (INIS)

    Kuhnt, T.; Pigorsch, S.; Pelz, T.; Haensgen, G.; Dunst, J.; Becker, A.; Bloching, M.; Passmann, M.; Lotterer, E.

    2003-01-01

    We have tested a very aggressive combination protocol with cisplatin and escalated paclitaxel in combination with accelerated hyperfractionated radiotherapy to assess the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), overall toxicity, and response rate. Patients and Methods: The trial recruited 24 patients (21 males, three females, mean age 57 years) treated at our department from 1998 through 2001. Irradiation was administered in daily doses of 2 Gy up to 30 Gy followed by 1.4 Gy twice daily up to 70.6 Gy to the primary tumor and involved nodes and 51 Gy to the clinically negative regional nodes. The chemotherapy schedule included cisplatin in a fixed dose of 20 mg/m 2 on days 1-5 and 29-33 and paclitaxel at increasing dose levels of 20, 25, 30 mg/m 2 twice weekly over the whole treatment time. Patients were recruited in cohorts of three to six, and the MTD was reached if two out of six patients in one cohort developed DLT. DLT was defined as any grade 4 toxicity or any grade 3 toxicity requiring treatment interruption or unplanned hospitalization or any grade 3 neurotoxicity. We recruited mainly patients with large tumors for this protocol; all patients were stage IV, and the mean tumor volume (primary + metastases) amounted to 72 ± 61 cm 3 . The mean follow-up was 30 months (range 4-39 months). Results: One early death (peritonitis and sepsis a t day 10) occurred, and 23 patients were evaluable for acute toxicity and response. The MTD of paclitaxel was reached at the third dose level (30 mg/m 2 paclitaxel twice weekly). The DLT was severe mucositis grade 3 (n = 1) and skin erythema grade 4 (n = 2). After determining the MTD, another 14 patients were treated at the recommended dose level of paclitaxel with 25 mg/m 2 twice weekly. In summary, 13/23 patients (57%) developed grade 3 and 10/23 (43%) grade 2 mucositis. Two patients (9%) had grade 4, five (22%) grade 3, and 16 (69%) grade 2 dermatitis. One patient died at day 30 of neutropenic infection

  19. Optimization of accelerator control

    International Nuclear Information System (INIS)

    Vasiljev, N.D.; Mozin, I.V.; Shelekhov, V.A.; Efremov, D.V.

    1992-01-01

    Expensive exploitation of charged particle accelerators is inevitably concerned with requirements of effectively obtaining of the best characteristics of accelerated beams for physical experiments. One of these characteristics is intensity. Increase of intensity is hindered by a number of effects, concerned with the influence of the volume charge field on a particle motion dynamics in accelerator's chamber. However, ultimate intensity, determined by a volume charge, is almost not achieved for the most of the operating accelerators. This fact is caused by losses of particles during injection, at the initial stage of acceleration and during extraction. These losses are caused by deviations the optimal from real characteristics of the accelerating and magnetic system. This is due to a number of circumstances, including technological tolerances on structural elements of systems, influence of measuring and auxiliary equipment and beam consumers' installations, placed in the closed proximity to magnets, and instability in operation of technological systems of accelerator. Control task consists in compensation of deviations of characteristics of magnetic and electric fields by optimal selection of control actions. As for technical means, automatization of modern accelerators allows to solve optimal control problems in real time. Therefore, the report is devoted to optimal control methods and experimental results. (J.P.N.)

  20. Electrostatic accelerators

    OpenAIRE

    Hinterberger, F

    2006-01-01

    The principle of electrostatic accelerators is presented. We consider Cockcroft– Walton, Van de Graaff and Tandem Van de Graaff accelerators. We resume high voltage generators such as cascade generators, Van de Graaff band generators, Pelletron generators, Laddertron generators and Dynamitron generators. The speci c features of accelerating tubes, ion optics and methods of voltage stabilization are described. We discuss the characteristic beam properties and the variety of possible beams. We ...

  1. Electrostatic accelerators

    CERN Document Server

    Hinterberger, F

    2006-01-01

    The principle of electrostatic accelerators is presented. We consider Cockcroft– Walton, Van de Graaff and Tandem Van de Graaff accelerators. We resume high voltage generators such as cascade generators, Van de Graaff band generators, Pelletron generators, Laddertron generators and Dynamitron generators. The speci c features of accelerating tubes, ion optics and methods of voltage stabilization are described. We discuss the characteristic beam properties and the variety of possible beams. We sketch possible applications and the progress in the development of electrostatic accelerators.

  2. Accelerator development

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Because the use of accelerated heavy ions would provide many opportunities for new and important studies in nuclear physics and nuclear chemistry, as well as other disciplines, both the Chemistry and Physics Divisions are supporting the development of a heavy-ion accelerator. The design of greatest current interest includes a tandem accelerator with a terminal voltage of approximately 25 MV injecting into a linear accelerator with rf superconducting resonators. This combined accelerator facility would be capable of accelerating ions of masses ranging over the entire periodic table to an energy corresponding to approximately 10 MeV/nucleon. This approach, as compared to other concepts, has the advantages of lower construction costs, lower operating power, 100 percent duty factor, and high beam quality (good energy resolution, good timing resolution, small beam size, and small beam divergence). The included sections describe the concept of the proposed heavy-ion accelerator, and the development program aiming at: (1) investigation of the individual questions concerning the superconducting accelerating resonators; (2) construction and testing of prototype accelerator systems; and (3) search for economical solutions to engineering problems. (U.S.)

  3. Collective ion acceleration

    International Nuclear Information System (INIS)

    Godfrey, B.B.; Faehl, R.J.; Newberger, B.S.; Shanahan, W.R.; Thode, L.E.

    1977-01-01

    Progress achieved in the understanding and development of collective ion acceleration is presented. Extensive analytic and computational studies of slow cyclotron wave growth on an electron beam in a helix amplifier were performed. Research included precise determination of linear coupling between beam and helix, suppression of undesired transients and end effects, and two-dimensional simulations of wave growth in physically realizable systems. Electrostatic well depths produced exceed requirements for the Autoresonant Ion Acceleration feasibility experiment. Acceleration of test ions to modest energies in the troughs of such waves was also demonstrated. Smaller efforts were devoted to alternative acceleration mechanisms. Langmuir wave phase velocity in Converging Guide Acceleration was calculated as a function of the ratio of electron beam current to space-charge limiting current. A new collective acceleration approach, in which cyclotron wave phase velocity is varied by modulation of electron beam voltage, is proposed. Acceleration by traveling Virtual Cathode or Localized Pinch was considered, but appears less promising. In support of this research, fundamental investigations of beam propagation in evacuated waveguides, of nonneutral beam linear eigenmodes, and of beam stability were carried out. Several computer programs were developed or enhanced. Plans for future work are discussed

  4. RECIRCULATING ACCELERATION

    International Nuclear Information System (INIS)

    BERG, J.S.; GARREN, A.A.; JOHNSTONE, C.

    2000-01-01

    This paper compares various types of recirculating accelerators, outlining the advantages and disadvantages of various approaches. The accelerators are characterized according to the types of arcs they use: whether there is a single arc for the entire recirculator or there are multiple arcs, and whether the arc(s) are isochronous or non-isochronous

  5. LIBO accelerates

    CERN Multimedia

    2002-01-01

    The prototype module of LIBO, a linear accelerator project designed for cancer therapy, has passed its first proton-beam acceleration test. In parallel a new version - LIBO-30 - is being developed, which promises to open up even more interesting avenues.

  6. Accelerating Inspire

    CERN Document Server

    AUTHOR|(CDS)2266999

    2017-01-01

    CERN has been involved in the dissemination of scientific results since its early days and has continuously updated the distribution channels. Currently, Inspire hosts catalogues of articles, authors, institutions, conferences, jobs, experiments, journals and more. Successful orientation among this amount of data requires comprehensive linking between the content. Inspire has lacked a system for linking experiments and articles together based on which accelerator they were conducted at. The purpose of this project has been to create such a system. Records for 156 accelerators were created and all 2913 experiments on Inspire were given corresponding MARC tags. Records of 18404 accelerator physics related bibliographic entries were also tagged with corresponding accelerator tags. Finally, as a part of the endeavour to broaden CERN's presence on Wikipedia, existing Wikipedia articles of accelerators were updated with short descriptions and links to Inspire. In total, 86 Wikipedia articles were updated. This repo...

  7. Novel applications of particle accelerators to radiotherapy

    International Nuclear Information System (INIS)

    Kreiner, A.J.; Burlon, A.A.; Universidad Nacional de San Martin, Villa Ballester

    2002-01-01

    Charged hadrons (protons and heavier ions) have very definite advantages over photons as far as radiotherapy applications are concerned. They allow for much better spatial dose localization due to their charge, relatively high mass and nature of the energy deposition process. In the frame of an attempt to promote the introduction of hadrontherapy in Argentina an external beam facility has been installed at our tandem accelerator TANDAR. The advantages of heavy ions can only be fully exploited for tumors of well defined localization. In certain types of malignancies, however, the region infiltrated by tumor cells is diffuse, with no sharp boundaries and with microscopic ramifications. In such cases (particularly in certain brain cancers) a more sophisticated scheme has been suggested called boron neutron capture therapy (BNCT). In this work, the use of the Tandar accelerator to produce neutrons for feasibility studies for BNCT through low-energy proton beams on a thick LiF target is being briefly described. Studies on the 13 C(d,n) reaction and a comparison with other neutron-producing reactions are also mentioned. Simulation work to optimize an accelerator-based neutron production target is discussed. A project is being prepared to develop a small proton accelerator in Argentina. Technical specifications of this machine are briefly discussed. (author)

  8. Compromised local control due to treatment interruptions and late treatment breaks in early glottic cancer: Population-based outcomes study supporting need for intensified treatment schedules

    International Nuclear Information System (INIS)

    Groome, Patti A.; O'Sullivan, Brian; Mackillop, William J.; Jackson, Lynda D.; Schulze, Karleen M.Math.; Irish, Jonathan C.; Warde, Padraig R.; Schneider, Ken M.; Mackenzie, Robert G.; Hodson, D. Ian; Hammond, J. Alex; Gulavita, Sunil P.P.; Eapen, Libni J.; Dixon, Peter F. M.B.; Bissett, Randy J.

    2006-01-01

    Purpose: This population-based study describes the treatment of early glottic cancer in Ontario, Canada and assesses whether treatment variations were associated with treatment effectiveness. Methods and Materials: We studied 491 T1N0 and 213 T2N0 patients. Data abstracted from charts included age, sex, stage, treatment details, disease control, and survival. Results: The total dose ranged from 50 to 70 Gy, and the daily dose ranged from 1.9 to 2.8 Gy. In 90%, treatment duration was between 25 and 50 days. Field sizes, field reductions, beam arrangement, and beam energy varied. Late treatment breaks occurred in 13.6% of T1N0 and 27.1% of T2N0 cases. Local control was comparable to other reports for T1N0 (82% at 5 years), but was only 63.2% in T2N0. Variables associated with local failure in T1N0 were age less than 49 years (relative risk [RR], 3.21; 95% confidence interval [CI], 1.49-6.90) and >3 treatment interruption days (RR, 2.43; 95% CI, 1.00-5.91). In T2N0, these were field reduction (RR, 2.33; 95% CI, 1.23-4.42) and late treatment breaks (RR, 2.19; 95% CI, 1.09-4.41). Conclusion: Some aspects of treatment for early glottic cancer were associated with worse local control. Problems with protracted treatment are of particular concern, underscoring the need for randomized studies to intensify radiotherapy

  9. Large electrostatic accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Jones, C.M.

    1984-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of large electrostatic accelerators designed to operate at terminal potentials of 20 MV or above. In this paper, the author briefly discusses the status of these new accelerators and also discusses several recent technological advances which may be expected to further improve their performance. The paper is divided into four parts: (1) a discussion of the motivation for the construction of large electrostatic accelerators, (2) a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, (3) a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and (4) a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year. Due to time and space constraints, discussion is restricted to consideration of only tandem accelerators.

  10. Large electrostatic accelerators

    International Nuclear Information System (INIS)

    Jones, C.M.

    1984-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of large electrostatic accelerators designed to operate at terminal potentials of 20 MV or above. In this paper, the author briefly discusses the status of these new accelerators and also discusses several recent technological advances which may be expected to further improve their performance. The paper is divided into four parts: (1) a discussion of the motivation for the construction of large electrostatic accelerators, (2) a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, (3) a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and (4) a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year. Due to time and space constraints, discussion is restricted to consideration of only tandem accelerators

  11. Painful stimulation and transient blocking of nerve transduction due to local anesthesia evoke perceptual distortions of the face in healthy volunteers.

    Science.gov (United States)

    Skyt, Ina; Dagsdóttir, Lilja; Vase, Lene; Baad-Hansen, Lene; Castrillon, Eduardo; Roepstorff, Andreas; Jensen, Troels Staehelin; Svensson, Peter

    2015-04-01

    Anecdotally, orofacial pain patients sometimes report that the painful face area feels "swollen." Because there are no clinical signs of swelling, such illusions may represent perceptual distortions. In this study, we examine whether nociceptive stimulation can lead to perceptual distortion of the face in a way similar to that of local anesthesia. Sixteen healthy participants received injections of .4 mL hypertonic saline to induce short-term nociceptive stimulation, .4 mL mepivacaine (local anesthetic) to transiently block nerve transduction, and .4 mL isotonic saline as a control condition. Injections were administered in both the infraorbital and the mental nerve regions. Perceptual distortions were conceptualized as perceived changes in magnitude of the injected areas and the lips, and they were measured using 1) a verbal subjective rating scale and 2) a warping procedure. Prior to the study, participants filled in several psychological questionnaires. This study shows that both nociceptive stimulation (P blocking of nerve transduction (P face. A test-retest experiment including 9 new healthy subjects supported the results. Perceptual distortions were positively correlated with the psychological variable of dissociation in several conditions (P face is important to understand the possible implications of perceptual distortions in orofacial pain disorders (and possibly other chronic pain states). Such information may ultimately open up new avenues of treatment for persistent orofacial pain. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

  12. SSC accelerator availability allocation

    International Nuclear Information System (INIS)

    Dixon, K.T.; Franciscovich, J.

    1991-03-01

    Superconducting Super Collider (SSC) operational availability is an area of major concern, judged by the Central Design Group to present such risk that use of modern engineering tools would be essential to program success. Experience has shown that as accelerator beam availability falls below about 80%, efficiency of physics experiments degrades rapidly due to inability to maintain adequate coincident accelerator and detector operation. For this reason, the SSC availability goal has been set at 80%, even though the Fermi National Accelerator Laboratory accelerator, with a fraction of the SSC's complexity, has only recently approached that level. This paper describes the allocation of the top-level goal to part-level reliability and maintainability requirements, and it gives the results of parameter sensitivity studies designed to help identify the best approach to achieve the needed system availability within funding and schedule constraints. 1 ref., 12 figs., 4 tabs

  13. FMIT accelerator

    International Nuclear Information System (INIS)

    Armstrong, D.D.

    1983-01-01

    A 35-MeV 100-mA cw linear accelerator is being designed by Los Alamos for use in the Fusion Materials Irradiation Test (FMIT) Facility. Essential to this program is the design, construction, and evaluation of performance of the accelerator's injector, low-energy beam transport, and radio-frequency quadrupole sections before they are shipped to the facility site. The installation and testing of some of these sections have begun as well as the testing of the rf, noninterceptive beam diagnostics, computer control, dc power, and vacuum systems. An overview of the accelerator systems and the performance to date is given

  14. Electron accelerator

    International Nuclear Information System (INIS)

    Abramyan.

    1981-01-01

    The USSR produces an electron accelerator family of a simple design powered straight from the mains. The specifications are given of accelerators ELITA-400, ELITA-3, ELT-2, TEUS-3 and RIUS-5 with maximum electron energies of 0.3 to 5 MeV, a mean power of 10 to 70 kW operating in both the pulsed and the continuous (TEUS-3) modes. Pulsed accelerators ELITA-400 and ELITA-3 and RIUS-5 in which TESLA resonance transformers are used are characterized by their compact size. (Ha)

  15. Familial prostate cancer has a more aggressive course than sporadic prostate cancer after treatment for localized disease, mainly due to a higher rate of distant metastases

    International Nuclear Information System (INIS)

    Kupelian, Patrick A.; Klein, Eric A.; Suh, John H; Kupelian, Varant A.

    1997-01-01

    Purpose: We had already established that familial prostate cancer, defined as prostate cancer diagnosed in a father or brother, was an independent predictor of biochemical failure after treatment for localized disease. Our aim was to determine whether differences in outcome could be observed with respect to clinical failures (either local or distant) between the two forms of prostate cancer. Methods: Of the 1685 consecutive cases with localized prostate carcinoma treated between 1986 and 1996, patients with the following were excluded from the present study: no pretreatment Prostatic Specific Antigen (iPSA) level (n=54), no biopsy Gleason score (bGS) (n=25), adjuvant or neoadjuvant treatment (n=234), no available follow-up PSA level (n=30). We also excluded 617 patients who did not have a minimum of 3 years potential follow-up. The analysis was performed on 725 cases. Radiotherapy (RT) was the primary treatment in 330 patients and radical prostatectomy (RP) in 395 patients. Five percent had clinical stage T3 disease (n=37). Positive family history was defined as the presence of prostate cancer in a first degree relative (father or brother). The outcomes of interest were biochemical relapse-free survival (bRFS), clinical relapse-free survival (cRFS), local relapse-free survival (locRFS), distant relapse-free survival (dRFS). We used proportional hazards to analyze the effect of family history and other potential confounding variables (i.e. age, race, treatment modality, stage, biopsy GS, and iPSA levels) on treatment outcome. We included pathologic findings (extracapsular extension, seminal vesicle involvement, surgical margin involvement, and lymph node metastases) in a separate analysis for RP patients. Results: The median follow-up was 45 months. Eight percent of all cases (n=57) had a positive family history. The 5-year bRFS rates for patients with negative and positive family history were 54% and 38%, respectively (p<0.001). The 5-year cRFS rates for patients

  16. Changes in lymphocyte subsets due to local irradiation of a portion of the maxilla in mice. A study of intracellular cytokine detection

    International Nuclear Information System (INIS)

    Momoi, Yukiko; Shirakawa, Masayori; Satoh, Daigo; Yosue, Takashi

    2008-01-01

    It is critical for dentists who perform radiation therapy to comprehend immunity, because irradiation therapy may damage lymphocytes. After local irradiation to the maxillary area of mice, naive T cells and memory T cells in the spleen, and Th1/Th2 balance and Tc1/Tc2 balance were investigated by intracellular cytokine detection. Female BALB/c mice at 5 weeks of age were adopted for the experiments. In the irradiation groups, a portion of the maxilla was exposed to X-rays (2.0 Gy/min, 10 Gy). Then lymphocytes were analyzed using flow cytometry (anti-CD4, CD62L-selectin and CD45RB monoclonal antibodies). The percentage of Th1 cells, Th2 cells, Tc1 cells, and Tc2 cells and the ratio of Th1/Th2 and Tc1/Tc2 were analyzed by intracellular cytokine detection, and the findings were compared with those of non-irradiated groups. The observation was performed 1 day before irradiation and 1, 3, 7, and 14 days after irradiation. The absolute number of naive T cells was significantly lower 1 and 3 days after irradiation. However, the absolute number of memory T cells did not change significantly after irradiation. The percentage of Th1, Th2, Tc1, and Tc2 cells did not change significantly after irradiation, either. There were no significant differences in the Th1/Th2 ratio and Tc1/Tc2 ratio were observed after irradiation. It was suggested that after the local irradiation the absolute number of naive T cells decreased, that the effect on memory T cells was minimal, and that irradiation did not affect either the ratio of Th1/Th2 nor that of Tc1/Tc2. (author)

  17. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  18. Acceleration theorems

    International Nuclear Information System (INIS)

    Palmer, R.

    1994-06-01

    Electromagnetic fields can be separated into near and far components. Near fields are extensions of static fields. They do not radiate, and they fall off more rapidly from a source than far fields. Near fields can accelerate particles, but the ratio of acceleration to source fields at a distance R, is always less than R/λ or 1, whichever is smaller. Far fields can be represented as sums of plane parallel, transversely polarized waves that travel at the velocity of light. A single such wave in a vacuum cannot give continuous acceleration, and it is shown that no sums of such waves can give net first order acceleration. This theorem is proven in three different ways; each method showing a different aspect of the situation

  19. LINEAR ACCELERATOR

    Science.gov (United States)

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  20. Health impact assessment and monetary valuation of IQ loss in pre-school children due to lead exposure through locally produced food.

    Science.gov (United States)

    Bierkens, J; Buekers, J; Van Holderbeke, M; Torfs, R

    2012-01-01

    A case study has been performed which involved the full chain assessment from policy drivers to health effect quantification of lead exposure through locally produced food on loss of IQ in pre-school children at the population level across the EU-27, including monetary valuation of the estimated health impact. Main policy scenarios cover the period from 2000 to 2020 and include the most important Community policy developments expected to affect the environmental release of lead (Pb) and corresponding human exposure patterns. Three distinct scenarios were explored: the emission situation based on 2000 data, a business-as-usual scenario (BAU) up to 2010 and 2020 and a scenario incorporating the most likely technological change expected (Most Feasible Technical Reductions, MFTR) in response to current and future legislation. Consecutive model calculations (MSCE-HM, WATSON, XtraFOOD, IEUBK) were performed by different partners on the project as part of the full chain approach to derive estimates of blood lead (B-Pb) levels in children as a consequence of the consumption of local produce. The estimated B-Pb levels were translated into an average loss of IQ points/child using an empirical relationship based on a meta-analysis performed by Schwartz (1994). The calculated losses in IQ points were subsequently further translated into the average cost/child using a cost estimate of €10.000 per loss of IQ point based on data from a literature review. The estimated average reduction of cost/child (%) for all countries considered in 2010 under BAU and MFTR are 12.16 and 18.08% as compared to base line conditions, respectively. In 2020 the percentages amount to 20.19 and 23.39%. The case study provides an example of the full-chain impact pathway approach taking into account all foreseeable pathways both for assessing the environmental fate and the associated human exposure and the mode of toxic action to arrive at quantitative estimates of health impacts at the individual and

  1. Localized nasal cavity, sinus, and massive bilateral orbital involvement by human T cell leukemia virus 1 adult T cell lymphoma, with epidermal hypertrophy due to mite infestation

    Directory of Open Access Journals (Sweden)

    Kathleen Laveaux

    2010-10-01

    Full Text Available HTLV1 adult T cell lymphoma occurs tends to be widely disseminated and aggressive, with only brief responses to chemotherapy. Aside from cervical adenopathy, involvement of head and neck structures is uncommon and orbital involvement rare. We report a case of nasal cavity HTLV lymphoma with massive bilateral orbital involvement and proptosis, resulting in complete left and partial right eye amaurosis. No other sites of disease were found. Response to chemotherapy was rapid and complete, with almost complete restoration of vision and oculo-motor function; the patient has remained in remission for one year. An associated problem was striking bilateral hypertrophic, hyperkeratotic eyelid and breast lesions due to mite infestation. 

  2. Keratomycosis due to Tintelnotia destructans refractory to common therapy treated successfully with systemic and local terbinafine in combination with polyhexamethylene biguanide.

    Science.gov (United States)

    Behrens-Baumann, Wolfgang J; Hofmüller, Wolfram; Tammer, Ina; Tintelnot, Kathrin

    2018-04-28

    To report on a wearer of rigid gas-permeable contact lenses with a keratomycosis due to Tintelnotia-a new genus of Phaeosphaeriaceae-treated with terbinafine and polyhexamethylene biguanide. Chart review of a patient with fungal keratitis treated additionally with systemic and topical terbinafine 0.25% after symptoms increased under conventional antimycotic therapy with voriconazole. Antifungal susceptibility had been tested in vitro. After starting an additional treatment with systemic and topical terbinafine, the severe corneal infection was sufficiently resolved. The drug was well tolerated without any neurological, dermatological or gastroenterological problems. Terbinafine revealed a marked in vitro antifungal activity of 0.12 µg/ml. The fungus was identified as Tintelnotia destructans. Terbinafine might be considered as a therapeutic option in severe cases of fungal keratitis refractory to common antifungal therapy.

  3. Universal behaviour of magnetoconductance due to week localization in two-dimensional systems - example of GaInAs quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Zduniak, A.; Dyakonov, M.I.; Litwin-Staszewska, E.; Knap, W. [Groupe d`Etudes des Semiconducteurs, Universite de Montpellier II, Montpellier (France)

    1995-12-31

    Week localization corrections to conductivity of two-dimensional electron gas are studied by measurements of magnetic field dependence of the conductivity in GaInAs quantum wells. We observed that, when presented as a function of the normalized magnetic field (x=B/B{sub tr} where B is the magnetic field, B{sub tr}=h/4e{tau}D, D is the diffusion constant and {tau} is momentum relaxation time), different samples show very similar high field behaviour. A theoretical description is developed that allows one to describe in a consistent way and low field behaviour. The theory predicts universal (B{sup -1/2}) behaviour of the conductivity correction for all 2D systems in high field limit (x>1). Low field behaviour depends strongly on spin and phase relaxation mechanisms. Comparison of the theory with experiment confirms the universal behaviour in the high field limit and allows one to estimate the spin and phase relaxation times for different GaInAs quantum wells. (author). 5 refs, 2 figs.

  4. Universal behaviour of magnetoconductance due to week localization in two-dimensional systems - example of GaInAs quantum wells

    International Nuclear Information System (INIS)

    Zduniak, A.; Dyakonov, M.I.; Litwin-Staszewska, E.; Knap, W.

    1995-01-01

    Week localization corrections to conductivity of two-dimensional electron gas are studied by measurements of magnetic field dependence of the conductivity in GaInAs quantum wells. We observed that, when presented as a function of the normalized magnetic field (x=B/B tr where B is the magnetic field, B tr =h/4eτD, D is the diffusion constant and τ is momentum relaxation time), different samples show very similar high field behaviour. A theoretical description is developed that allows one to describe in a consistent way and low field behaviour. The theory predicts universal (B -1/2 ) behaviour of the conductivity correction for all 2D systems in high field limit (x>1). Low field behaviour depends strongly on spin and phase relaxation mechanisms. Comparison of the theory with experiment confirms the universal behaviour in the high field limit and allows one to estimate the spin and phase relaxation times for different GaInAs quantum wells. (author)

  5. Changes in lymphocyte subsets due to local irradiation of a portion of the maxilla in mice. A study of minor population lymphocytes

    International Nuclear Information System (INIS)

    Yamashita, Chiho; Satoh, Daigo; Yosue, Takashi

    2001-01-01

    In the present study we investigates the influence of the local irradiation of a portion of the maxilla on the numbers of lymphocyte subsets in peripheral blood and spleen, specifically minor population lymphocytes (γδT cells and NKT cells). Male C57BL/6 mice at 15 weeks of age were used for the experiments. In the irradiation group, a portion of the maxilla was exposed to X-ray (2.0 Gy/min, 10 Gy) and we analyzed lymphocytes using flow cytometry (anti-CD3, CD4, CD8, TCRαβ, TCRγδ and NK1.1 monoclonal antibodies), and compared the outcome to that obtained from the non-irradiation groups. The following results were obtained: In peripheral blood, CD4 + SP T cells, CD8 + SP T cells, αβ T cells, γδ T cells and NK cells decreased significantly on the first day and third day after irradiation. NKT cells decreased significantly on the third day after irradiation. In spleen, CD4 + SP T cells, CD8 + SP T cells, αβ T cells and γδ T cells decreased significantly on the first day after irradiation. NK cells and NKT cells did not change significantly after irradiation. The above results indicate that the changes in lymphocytes have a direct relationship to radiosensitivity, and the origin and distribution in lymphocyte subsets. (author)

  6. Changes in thymocytes due to local irradiation of a portion of the maxilla in mice. A study of NKT cells and γδT cells

    International Nuclear Information System (INIS)

    Satho, Taigo; Tamasawa, Ken; Yosue, Takashi; Arai, Thiaki

    2000-01-01

    We have been investigating the changes of lymphocyte subsets in immune organs after head and neck irradiation. The aim of the present study was to determine the influence of local irradiation (10 Gy) of a portion of the maxilla on the thymocyte subsets, specifically NKT cells and γδT cells in mice. The thymocyte subsets were analyzed following irradiation using a fluorometer (anti-CD4, CD8, TCRαβ, TCRγδ and NK1.1 monoclonal antibodies) and the outcome compared with that obtained from no-irradiation groups. The following results were obtained: The total number of thymocytes showed a significant decrease one day and three days after irradiation. The absolute number of DN (double negative; CD4 - CD8 - ), CD4 + SP (CD4 + single positive; CD4 + CD8 - ) and CD8 + SP (CD8 + single positive; CD4 - CD8 + ) thymocytes showed a significant decrease one day after irradiation. The absolute number of DP (double positive; CD4 + CD8 + ) thymocytes showed a significant decrease one day and three days after irradiation. The absolute number of NKT and γδT cells showed a significant decrease one day after irradiation. In conclusion, the results suggest that NKT cells and γδT cells exhibit behavior which is the same as main stream thymocytes, except DP thymocytes. (author)

  7. Changes in lymphocyte subsets due to local irradiation of a portion of the maxilla in mice. A study of minor population lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Chiho; Satoh, Daigo; Yosue, Takashi [Nippon Dental Univ., Tokyo (Japan). School of Dentistry

    2001-03-01

    In the present study we investigates the influence of the local irradiation of a portion of the maxilla on the numbers of lymphocyte subsets in peripheral blood and spleen, specifically minor population lymphocytes ({gamma}{delta}T cells and NKT cells). Male C57BL/6 mice at 15 weeks of age were used for the experiments. In the irradiation group, a portion of the maxilla was exposed to X-ray (2.0 Gy/min, 10 Gy) and we analyzed lymphocytes using flow cytometry (anti-CD3, CD4, CD8, TCR{alpha}{beta}, TCR{gamma}{delta} and NK1.1 monoclonal antibodies), and compared the outcome to that obtained from the non-irradiation groups. The following results were obtained: In peripheral blood, CD4{sup +}SP T cells, CD8{sup +}SP T cells, {alpha}{beta} T cells, {gamma}{delta} T cells and NK cells decreased significantly on the first day and third day after irradiation. NKT cells decreased significantly on the third day after irradiation. In spleen, CD4{sup +}SP T cells, CD8{sup +}SP T cells, {alpha}{beta} T cells and {gamma}{delta} T cells decreased significantly on the first day after irradiation. NK cells and NKT cells did not change significantly after irradiation. The above results indicate that the changes in lymphocytes have a direct relationship to radiosensitivity, and the origin and distribution in lymphocyte subsets. (author)

  8. Changes in thymocytes due to local irradiation of a portion of the maxilla in mice. A study of NKT cells and {gamma}{delta}T cells

    Energy Technology Data Exchange (ETDEWEB)

    Satho, Taigo; Tamasawa, Ken; Yosue, Takashi [Nippon Dental Univ., Tokyo (Japan); Arai, Thiaki

    2000-07-01

    We have been investigating the changes of lymphocyte subsets in immune organs after head and neck irradiation. The aim of the present study was to determine the influence of local irradiation (10 Gy) of a portion of the maxilla on the thymocyte subsets, specifically NKT cells and {gamma}{delta}T cells in mice. The thymocyte subsets were analyzed following irradiation using a fluorometer (anti-CD4, CD8, TCR{alpha}{beta}, TCR{gamma}{delta} and NK1.1 monoclonal antibodies) and the outcome compared with that obtained from no-irradiation groups. The following results were obtained: The total number of thymocytes showed a significant decrease one day and three days after irradiation. The absolute number of DN (double negative; CD4{sup -} CD8{sup -}), CD4{sup +} SP (CD4{sup +} single positive; CD4{sup +} CD8{sup -}) and CD8{sup +} SP (CD8{sup +} single positive; CD4{sup -} CD8{sup +}) thymocytes showed a significant decrease one day after irradiation. The absolute number of DP (double positive; CD4{sup +} CD8{sup +}) thymocytes showed a significant decrease one day and three days after irradiation. The absolute number of NKT and {gamma}{delta}T cells showed a significant decrease one day after irradiation. In conclusion, the results suggest that NKT cells and {gamma}{delta}T cells exhibit behavior which is the same as main stream thymocytes, except DP thymocytes. (author)

  9. New approach in two-dimensional fluid modeling of edge plasma transport with high intermittency due to blobs and edge localized modes

    International Nuclear Information System (INIS)

    Pigarov, A. Yu.; Krasheninnikov, S. I.; Rognlien, T. D.

    2011-01-01

    A new approach is proposed to simulate intermittent, non-diffusive plasma transport (via blobs and filaments of edge localized modes (ELMs)) observed in the tokamak edge region within the framework of two-dimensional transport codes. This approach combines the inherently three-dimensional filamentary structures associated with an ensemble of blobs into a macro-blob in the two-dimensional poloidal cross-section and advects the macro-blob ballistically across the magnetic field, B. Intermittent transport is represented as a sequence of macro-blobs appropriately seeded in the edge plasma according to experimental statistics. In this case, the code is capable of reproducing both the long-scale temporal evolution of the background plasma and the fast spatiotemporal dynamics of blobs. We report the results from a two-dimensional edge plasma code modeling of a single macro-blob dynamics, and its interaction with initially stationary background plasma as well as with material surfaces. The mechanisms of edge plasma particle and energy losses from macro-blobs are analyzed. The effects of macro-blob sizes and advection velocity on edge plasma profiles are studied. The macro-blob impact on power loading and sputtering rates on the chamber wall and on inner and outer divertor plates is discussed. Temporal evolution of particle inventory of the edge plasma perturbed by macro-blobs is analyzed. Application of macro-blobs to ELM modeling is highlighted.

  10. Due diligence

    International Nuclear Information System (INIS)

    Sanghera, G.S.

    1999-01-01

    The Occupational Health and Safety (OHS) Act requires that every employer shall ensure the health and safety of workers in the workplace. Issues regarding the practices at workplaces and how they should reflect the standards of due diligence were discussed. Due diligence was described as being the need for employers to identify hazards in the workplace and to take active steps to prevent workers from potentially dangerous incidents. The paper discussed various aspects of due diligence including policy, training, procedures, measurement and enforcement. The consequences of contravening the OHS Act were also described

  11. Spatial dependence and origin of the ambient dose due to neutron activation processes in linear accelerators; Dependencia espacial y origen de la dosis ambiental debeda a procesos de activacion neutronica en aceleradores lineales

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Egea, E.; Sanchez Carrascal, M.; Torres Pozas, S.; Monja Ray, P. de la; Perez Molina, J. L.; Madan Rodriguez, C.; Luque Japon, L.; Morera Molina, A.; Hernandez Perez, A.; Barquero Bravo, Y.; Morengo Pedagna, I.; Oliva Gordillo, M. C.; Martin Olivar, R.

    2011-07-01

    In order to try to determine the high dose in the bunker of a Linear Accelerator clinical use trying to measure the spatial dependence of the same from the isocenter to gateway to the board cheeking to establish the origin of it. This dose measurements performed with an ionization chamber at different locations inside the bunker after an irradiation of 400 Monitor Units verifying the dose rate per minute for an hour, and accumulating the dose received during that period of time.

  12. Quando la fiction produce turismo. Due località per il cinema fantasy a confronto / When fiction produces tourism. Two localities for fantasy cinema in comparison

    Directory of Open Access Journals (Sweden)

    Antonio Violante

    2016-05-01

    Full Text Available Dubrovnik, capitale del mondo medioevale fantasy della serie televisiva Game of Thrones, in cui essa è ambientata, è stata sottoposta a una “invasione” turistica non tanto per i suoi pregi in sé, quanto perché le sue strutture fungono da scenario alla fiction, da diventare proprio per questo meritevoli di visita. Si sono organizzati tour alla visita dei luoghi del set, con tanto di merchandising connesso.L’interesse verso gli ksour tunisini utilizzati nelle riprese dei film componenti la saga fantascientifica di Star Wars, ha prodotto un altro caso di turismo cinematografico. Infatti, Star Wars ha inciso profondamente sull’immagine turistica della Tunisia, anche ad anni di distanza dalle riprese colà avvenute.     Il metodo comparativo di indagine su queste località, condotta sulla base della documentazione esistente e di una ricognizione dei luoghi, ha mirato a porre in evidenza le contraddizioni in cui esse sono incorse; infatti, da centri celebri per i loro pregi artistici e architettonici, sono diventate poli di attrazione turistica in quanto  scenari per fiction di successo.   Dubrovnik – the capital of the Medieval fantasy world of the tv show Game of Thrones – has been “invaded” by tourists not just because its own merits, but especially because it is the scenary of the tv fiction and therefore worthy of visiting. There have been tours to set locations and all the connected merchandising. The interest towards the Tunisian ksour used during shooting of the movies within the sci-fi saga Star Wars produced another case of cinema tourism. In fact, Star Wars made a profound impact on Tunisia’s touristic image, despite all the years that have passed since the making of the movie.The comparative method used to analyse these localities, based on existing documentation and first-hand visits aims to highlight the contradictions noticed: in fact, instead of being famous for their artistic and architectural values, they

  13. Study of Air Pollution Due to Plasma Cutting Process and Designing Local Ventilation System with Collector in Central Workshop of Mobarakeh Steel Company

    Directory of Open Access Journals (Sweden)

    Farideh Atabi

    2014-06-01

    Full Text Available Background & Objectives : Cutting leads to production of different hazardous agents such as fumes, particles, gases and vapors. In various studies, the effects of fumes, gases, and vapors on workers and environment have been proved. Meanwhile, cutting alloying plates with plasma cutting machine due to containing various alloy materials produces a lot of air pollution. Therefore, using the ventilation system to remove the mentioned pollution has always been noteworthy. Method: This study was performed on plasma cutting machine at Mobarakeh Steel Company. At first, according to ASTM the elements from alloy plates with optical emission spectrometry crm-35000-quantometery were detected, the air pollution from cutting the mentioned plates was sampled and measured using NIOSH 7300 method and according to the ACGIH:VS-72-20, VS-70-12, VS-70-11 VS-916 push-pull ventilation with bag filter collector was designed. Results: Results of sampling from pollution of cutting the alloy material, concentration of iron, lead and cadmium fumes were more than the standard limits. After calculation for push system, air flow volume of 195.163 cfm, outgoing air velocity of 5937.4 fpm and for pull system air flow volume of 12498 cfm, minimum duct velocity of 3000 fpm and velocity pressure of duct of 0.717 inwg, for fan, total pressure of 6.301 inwg, static pressure of 0.587 inwg and power of 20.65 Bhp and for collector with pulse jet cleaning system air to cloth ratio of 7 and dimensions of 6.88ft × 6.56ft × 9.84ft were obtained. Conclusion: The result of study indicated that push pull ventilation compared to other ventilation system s for plasma cutting has more efficiency and makes suitable control for pollution.

  14. Medical uses of accelerators

    International Nuclear Information System (INIS)

    Bradbury, J.N.

    1981-01-01

    A variety of particle accelerators have either potential or already demonstrated uses in connection with medically-related research, diagnosis, and treatment. For cancer radiotherapy, nuclear particles including protons, neutrons, heavy ions, and negative pi mesons have advantages compared to conventional radiations in terms of dose localization and/or biological effectiveness. Clinical evaluations of these particles are underway at a number of institutions. Accelerator-produced radionuclides are in widespread use for research and routine diagnostic purposes. Elemental analysis techniques with charged particles and neutrons are being applied to bone, blood, and other tissues. Finally, low-dose medical imaging can be accomplished with accelerated protons and heavy ions. The status and future of these programs are discussed

  15. Acceleration effects on missile aerodynamics

    CSIR Research Space (South Africa)

    Gledhill, Irvy MA

    2010-09-01

    Full Text Available Practical requirements are now arising in which significant acceleration takes place during flight; 5th generation missiles, such as A-Darter, execute turns at 100 g, where g is the acceleration due to gravity, and thrust from propulsion systems may...

  16. Accelerator microanalysis

    International Nuclear Information System (INIS)

    Tuniz, C.

    1997-01-01

    Particle accelerators have been developed more than sixty years ago to investigate nuclear and atomic phenomena. A major shift toward applications of accelerators in the study of materials structure and composition in inter-disciplinary projects has been witnessed in the last two decades. The Australian Nuclear Science and Technology Organisation (ANSTO) has developed advanced research programs based on the use of particle and photon beams. Atmospheric pollution problems are investigated at the 3 MV Van de Graff accelerator using ion beam analysis techniques to detect toxic elements in aerosol particles. High temperature superconductor and semiconductor materials are characterised using the recoil of iodine and other heavy ions produced at ANTARES, the 10-MV Tandem accelerator. A heavy-ion microprobe is presently being developed at ANTARES to map elemental concentrations of specific elements with micro-size resolution. An Accelerator mass Spectrometry (AMS) system has been developed at ANSTO for the ultra-sensitive detection of Carbon-14, Iodine-129 and other long-lived radioisotopes. This AMS spectrometer is a key instrument for climate change studies and international safeguards. ANSTO is also managing the Australian Synchrotron Research program based on facilities developed at the Photon Factory (Japan) and at the Advanced Photon Source (USA). Advanced projects in biology, materials chemistry, structural condensed matter and other disciplines are being promoted by a consortium involving Australian universities and research institutions. This paper will review recent advances in the use of particle accelerators, with a particular emphasis on applications developed at ANSTO and related to problems of international concern, such as global environmental change, public health and nuclear proliferation

  17. Acceleration of polarized particles

    International Nuclear Information System (INIS)

    Buon, J.

    1992-05-01

    The spin kinetics of polarized beams in circular accelerators is reviewed in the case of spin-1/2 particles (electrons and protons) with emphasis on the depolarization phenomena. The acceleration of polarized proton beams in synchrotrons is described together with the cures applied to reduce depolarization, including the use of 'Siberian Snakes'. The in-situ polarization of electrons in storage rings due to synchrotron radiation is studied as well as depolarization in presence of ring imperfections. The applications of electron polarization to accurately calibrate the rings in energy and to use polarized beams in colliding-beam experiments are reviewed. (author) 76 refs., 19 figs., 1 tab

  18. Induction Chemotherapy and Continuous Hyperfractionated Accelerated Radiotherapy (CHART) for Patients With Locally Advanced Inoperable Non-Small-Cell Lung Cancer: The MRC INCH Randomized Trial

    International Nuclear Information System (INIS)

    Hatton, Matthew; Nankivell, Matthew; Lyn, Ethan; Falk, Stephen; Pugh, Cheryl; Navani, Neal; Stephens, Richard; Parmar, Mahesh

    2011-01-01

    Purpose: Recent clinical trials and meta-analyses have shown that both CHART (continuous hyperfractionated accelerated radiation therapy) and induction chemotherapy offer a survival advantage over conventional radical radiotherapy for patients with inoperable non-small cell-lung cancer (NSCLC). This multicenter randomized controlled trial (INCH) was set up to assess the value of giving induction chemotherapy before CHART. Methods and Materials: Patients with histologically confirmed, inoperable, Stage I-III NSCLC were randomized to induction chemotherapy (ICT) (three cycles of cisplatin-based chemotherapy followed by CHART) or CHART alone. Results: Forty-six patients were randomized (23 in each treatment arm) from 9 UK centers. As a result of poor accrual, the trial was closed in December 2007. Twenty-eight patients were male, 28 had squamous cell histology, 34 were Stage IIIA or IIIB, and all baseline characteristics were well balanced between the two treatment arms. Seventeen (74%) of the 23 ICT patients completed the three cycles of chemotherapy. All 42 (22 CHART + 20 ICT) patients who received CHART completed the prescribed treatment. Median survival was 17 months in the CHART arm and 25 months in the ICT arm (hazard ratio of 0.60 [95% CI 0.31-1.16], p = 0.127). Grade 3 or 4 adverse events (mainly fatigue, dysphagia, breathlessness, and anorexia) were reported for 13 (57%) CHART and 13 (65%) ICT patients. Conclusions: This small randomized trial indicates that ICT followed by CHART is feasible and well tolerated. Despite closing early because of poor accrual, and so failing to show clear evidence of a survival benefit for the additional chemotherapy, the results suggest that CHART, and ICT before CHART, remain important options for the treatment of inoperable NSCLC and deserve further study.

  19. Accelerator operations

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    This section is concerned with the operation of both the tandem-linac system and the Dynamitron, two accelerators that are used for entirely different research. Developmental activities associated with the tandem and the Dynamitron are also treated here, but developmental activities associated with the superconducting linac are covered separately because this work is a program of technology development in its own right

  20. CNSTN Accelerator

    International Nuclear Information System (INIS)

    Habbassi, Afifa; Trabelsi, Adel

    2010-01-01

    This project give a big idea about the measurement of the linear accelerator in the CNSTN. During this work we control dose distribution for different product. For this characterisation we have to make an installation qualification ,operational qualification,performance qualification and of course for every step we have to control temperature and the dose ,even the distribution of the last one.

  1. Accelerators course

    CERN Multimedia

    CERN. Geneva HR-RFA; Métral, E

    2006-01-01

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges

  2. Accelerator operations

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Operations of the SuperHILAC, the Bevatron/Bevalac, and the 184-inch Synchrocyclotron during the period from October 1977 to September 1978 are discussed. These include ion source development, accelerator facilities, the Heavy Ion Spectrometer System, and Bevelac biomedical operations

  3. Accelerator update

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    When the Accelerator Conference, combined International High Energy and US Particle versions, held in Dallas in May, was initially scheduled, progress nearby for the US Superconducting Supercollider was high on the preliminary agenda. With the SSC voted down by Congress in October 1993, this was no longer the case. However the content of the meeting, in terms of both its deep implications for ambitious new projects and the breadth of its scope, showed that the worldwide particle accelerator field is far from being moribund. A traditional feature of such accelerator conferences is the multiplicity of parallel sessions. No one person can attend all sessions, so that delegates can follow completely different paths and emerge with totally different impressions. Despite this overload, and despite the SSC cancellation, the general picture is one of encouraging progress over a wide range of major new projects throughout the world. At the same time, spinoff from, and applications of, accelerators and accelerator technology are becoming increasingly important. Centrestage is now CERN's LHC proton-proton collider, where a test string of superconducting magnets is operating over long periods at the nominal LHC field of 8.36 tesla or more. The assignment of the underground areas in the existing 27- kilometre LEP tunnel is now quasidefinitive (see page 3). For CERN's existing big machine, the LEP electron-positron collider, ongoing work concentrates on boosting performance using improved optics and bunch trains. But the main objective is the LEP2 scheme using superconducting accelerating cavities to boost the beam energy (see page 6). After some initial teething problems, production and operation of these cavities appears to have been mastered, at least under test conditions. A highlight at CERN last year was the first run with lead ions (December 1994, page 15). Handling these heavy particles with systems originally designed for protons calls for ingenuity. The SPS

  4. Accelerator update

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-09-15

    When the Accelerator Conference, combined International High Energy and US Particle versions, held in Dallas in May, was initially scheduled, progress nearby for the US Superconducting Supercollider was high on the preliminary agenda. With the SSC voted down by Congress in October 1993, this was no longer the case. However the content of the meeting, in terms of both its deep implications for ambitious new projects and the breadth of its scope, showed that the worldwide particle accelerator field is far from being moribund. A traditional feature of such accelerator conferences is the multiplicity of parallel sessions. No one person can attend all sessions, so that delegates can follow completely different paths and emerge with totally different impressions. Despite this overload, and despite the SSC cancellation, the general picture is one of encouraging progress over a wide range of major new projects throughout the world. At the same time, spinoff from, and applications of, accelerators and accelerator technology are becoming increasingly important. Centrestage is now CERN's LHC proton-proton collider, where a test string of superconducting magnets is operating over long periods at the nominal LHC field of 8.36 tesla or more. The assignment of the underground areas in the existing 27- kilometre LEP tunnel is now quasidefinitive (see page 3). For CERN's existing big machine, the LEP electron-positron collider, ongoing work concentrates on boosting performance using improved optics and bunch trains. But the main objective is the LEP2 scheme using superconducting accelerating cavities to boost the beam energy (see page 6). After some initial teething problems, production and operation of these cavities appears to have been mastered, at least under test conditions. A highlight at CERN last year was the first run with lead ions (December 1994, page 15). Handling these heavy particles with systems originally designed for protons calls for ingenuity. The SPS has managed

  5. Prospective study of accelerated postoperative radiation therapy in patients with squamous-cell carcinoma of the head and neck; Radiotherapie externe acceleree postoperatoire des carcinomes epidermoides localement evolues de la sphere ORL: etude prospective de phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Zouhair, A.; Coucke, P.A.; Azria, D.; Moeckli, R.; Mirimanoff, R.O.; Ozsahin, M. [Centre Hospitalier Universitaire Vaudois CHUV, Service de Radio-Oncologie, Lausanne (Switzerland); Azria, D. [Centre Regional de Lutte Contre le Cancer Val-d' Aurelle-Paul-Lamarque, Dept. d' Oncologie- Radiotherapie, 34 - Montpellier (France); Pache, P. [Centre Hospitalier Universitaire Vaudois CHUV, Service d' ORL, Lausanne (Switzerland); Stupp, R. [Centre hospitalier Universitaire Vaudois CHUV, Centre Pluridisciplinaire d' Oncologie Medicale, Lausanne (Switzerland)

    2003-08-01

    Purpose. - To assess the feasibility and efficacy of accelerated postoperative radiation therapy (RT) in patients with squamous-cell carcinoma of the head and neck (SCCHN). Patients and methods. - Between December 1997 and July 2001, 68 patients (male to female ratio: 52/16; median age: 60-years (range: 43-81)) with pT1-pT4 and/or pN0-pN3 SCCHN (24 oropharynx, 19 oral cavity, 13 hypopharynx, 5 larynx, 3 unknown primary, 2 maxillary sinus, and 2 salivary gland) were included in this prospective study. Postoperative RT was indicated because extra-capsular infiltration (ECT) was observed in 20 (29%), positive surgical margins (PSM) in 20 (29%) or both in 23 patients (34%). Treatment consisted of external beam R 66 Gy in 5 weeks and 3 days. Median follow-up was 15 months. Results. -According to CTC 2.0, acute morbidity was acceptable: grade 3 mucositis was observed in 15 (22%) patients, grade 3 dysphagia in 19 (28%) patients, grade 3 skin erythema in 21 (31%) patients with a median weight loss of 3.1 kg (range: 0-16). No grade 4 toxicity wa observed. Median time to relapse was 13 months; we observed only three (4%) local and four (6%) regional relapses, whereas eight (12%) patients developed distant metastases without any evidence of locoregional recurrence. The 2 years overall-, disease-free survival, an actuarial locoregional control rates were 85, 73 and 83% respectively. Conclusion.- The reduction of the overall treatment time using postoperative accelerated RT with weekly concomitant boost (six fraction per week) is feasible with local control rates comparable to that of published data. Acute RT related morbidity is acceptable. (author)

  6. Accelerating volumetric cine MRI (VC-MRI) using undersampling for real-time 3D target localization/tracking in radiation therapy: a feasibility study

    Science.gov (United States)

    Harris, Wendy; Yin, Fang-Fang; Wang, Chunhao; Zhang, You; Cai, Jing; Ren, Lei

    2018-01-01

    Purpose. To accelerate volumetric cine MRI (VC-MRI) using undersampled 2D-cine MRI to provide real-time 3D guidance for gating/target tracking in radiotherapy. Methods. 4D-MRI is acquired during patient simulation. One phase of the prior 4D-MRI is selected as the prior images, designated as MRIprior. The on-board VC-MRI at each time-step is considered a deformation of the MRIprior. The deformation field map is represented as a linear combination of the motion components extracted by principal component analysis from the prior 4D-MRI. The weighting coefficients of the motion components are solved by matching the corresponding 2D-slice of the VC-MRI with the on-board undersampled 2D-cine MRI acquired. Undersampled Cartesian and radial k-space acquisition strategies were investigated. The effects of k-space sampling percentage (SP) and distribution, tumor sizes and noise on the VC-MRI estimation were studied. The VC-MRI estimation was evaluated using XCAT simulation of lung cancer patients and data from liver cancer patients. Volume percent difference (VPD) and Center of Mass Shift (COMS) of the tumor volumes and tumor tracking errors were calculated. Results. For XCAT, VPD/COMS were 11.93  ±  2.37%/0.90  ±  0.27 mm and 11.53  ±  1.47%/0.85  ±  0.20 mm among all scenarios with Cartesian sampling (SP  =  10%) and radial sampling (21 spokes, SP  =  5.2%), respectively. When tumor size decreased, higher sampling rate achieved more accurate VC-MRI than lower sampling rate. VC-MRI was robust against noise levels up to SNR  =  20. For patient data, the tumor tracking errors in superior-inferior, anterior-posterior and lateral (LAT) directions were 0.46  ±  0.20 mm, 0.56  ±  0.17 mm and 0.23  ±  0.16 mm, respectively, for Cartesian-based sampling with SP  =  20% and 0.60  ±  0.19 mm, 0.56  ±  0.22 mm and 0.42  ±  0.15 mm, respectively, for

  7. Two-way regulation between cells and aligned collagen fibrils: local 3D matrix formation and accelerated neural differentiation of human decidua parietalis placental stem cells.

    Science.gov (United States)

    Li, Wen; Zhu, Bofan; Strakova, Zuzana; Wang, Rong

    2014-08-08

    It has been well established that an aligned matrix provides structural and signaling cues to guide cell polarization and cell fate decision. However, the modulation role of cells in matrix remodeling and the feedforward effect on stem cell differentiation have not been studied extensively. In this study, we report on the concerted changes of human decidua parietalis placental stem cells (hdpPSCs) and the highly ordered collagen fibril matrix in response to cell-matrix interaction. With high-resolution imaging, we found the hdpPSCs interacted with the matrix by deforming the cell shape, harvesting the nearby collagen fibrils, and reorganizing the fibrils around the cell body to transform a 2D matrix to a localized 3D matrix. Such a unique 3D matrix prompted high expression of β-1 integrin around the cell body that mediates and facilitates the stem cell differentiation toward neural cells. The study offers insights into the coordinated, dynamic changes at the cell-matrix interface and elucidates cell modulation of its matrix to establish structural and biochemical cues for effective cell growth and differentiation. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Laser acceleration

    Science.gov (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  9. Laser acceleration

    International Nuclear Information System (INIS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-01-01

    The fundamental idea of LaserWakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wake fields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ∼ c and ultra fastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nano materials is also emerging.

  10. Accelerating networks

    International Nuclear Information System (INIS)

    Smith, David M D; Onnela, Jukka-Pekka; Johnson, Neil F

    2007-01-01

    Evolving out-of-equilibrium networks have been under intense scrutiny recently. In many real-world settings the number of links added per new node is not constant but depends on the time at which the node is introduced in the system. This simple idea gives rise to the concept of accelerating networks, for which we review an existing definition and-after finding it somewhat constrictive-offer a new definition. The new definition provided here views network acceleration as a time dependent property of a given system as opposed to being a property of the specific algorithm applied to grow the network. The definition also covers both unweighted and weighted networks. As time-stamped network data becomes increasingly available, the proposed measures may be easily applied to such empirical datasets. As a simple case study we apply the concepts to study the evolution of three different instances of Wikipedia, namely, those in English, German, and Japanese, and find that the networks undergo different acceleration regimes in their evolution

  11. Requirements of a proton beam accelerator for an accelerator-driven reactor

    International Nuclear Information System (INIS)

    Takahashi, H.; Zhao, Y.; Tsoupas, N.; An, Y.; Yamazaki, Y.

    1997-01-01

    When the authors first proposed an accelerator-driven reactor, the concept was opposed by physicists who had earlier used the accelerator for their physics experiments. This opposition arose because they had nuisance experiences in that the accelerator was not reliable, and very often disrupted their work as the accelerator shut down due to electric tripping. This paper discusses the requirements for the proton beam accelerator. It addresses how to solve the tripping problem and how to shape the proton beam

  12. Advanced concepts for acceleration

    International Nuclear Information System (INIS)

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations

  13. Accelerators and the Accelerator Community

    Energy Technology Data Exchange (ETDEWEB)

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  14. Accelerators and the Accelerator Community

    International Nuclear Information System (INIS)

    Malamud, Ernest; Sessler, Andrew

    2008-01-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process

  15. The Research of Vehicle Acceleration at Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Vuk Bogdanović

    2013-02-01

    Full Text Available Vehicle acceleration is an important parameter used in planning various road elements, traffic signalization, geometric elements of an intersection, signal plans of traffic lights, etc. The knowledge of vehicle acceleration values is also necessary in using simulation softwares for more accurate analysis of the total situation at an intersection, on a road section or in a traffic network. In a lot of earlier studies, acceleration values were analysed and defined, mostly in optimal conditions for traffic functioning. However, values of almost all traffic flow parameters have been changed over time, due to changes in driving-dynamic vehicle characteristics, pneumatic tyres, material used for building road surface, etc. Besides, local environment influence and changes in drivers’ behaviour also significantly affect values of this parameter. According to HCM, it is advisable to perform local research for all values of the parameters recommended within the framework of this handbook, and to adapt their values to local conditions as well. The results of measuring the values of vehicles acceleration at signalized intersections in Novi Sad, Serbia, have been shown in this paper, using the procedure based on video recording processing.

  16. Accelerated Profile HMM Searches.

    Directory of Open Access Journals (Sweden)

    Sean R Eddy

    2011-10-01

    Full Text Available Profile hidden Markov models (profile HMMs and probabilistic inference methods have made important contributions to the theory of sequence database homology search. However, practical use of profile HMM methods has been hindered by the computational expense of existing software implementations. Here I describe an acceleration heuristic for profile HMMs, the "multiple segment Viterbi" (MSV algorithm. The MSV algorithm computes an optimal sum of multiple ungapped local alignment segments using a striped vector-parallel approach previously described for fast Smith/Waterman alignment. MSV scores follow the same statistical distribution as gapped optimal local alignment scores, allowing rapid evaluation of significance of an MSV score and thus facilitating its use as a heuristic filter. I also describe a 20-fold acceleration of the standard profile HMM Forward/Backward algorithms using a method I call "sparse rescaling". These methods are assembled in a pipeline in which high-scoring MSV hits are passed on for reanalysis with the full HMM Forward/Backward algorithm. This accelerated pipeline is implemented in the freely available HMMER3 software package. Performance benchmarks show that the use of the heuristic MSV filter sacrifices negligible sensitivity compared to unaccelerated profile HMM searches. HMMER3 is substantially more sensitive and 100- to 1000-fold faster than HMMER2. HMMER3 is now about as fast as BLAST for protein searches.

  17. Virtual gap dielectric wall accelerator

    Science.gov (United States)

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  18. Long-Term Outcome and Morbidity After Treatment With Accelerated Radiotherapy and Weekly Cisplatin for Locally Advanced Head-and-Neck Cancer: Results of a Multidisciplinary Late Morbidity Clinic

    International Nuclear Information System (INIS)

    Rütten, Heidi; Pop, Lucas A.M.; Janssens, Geert O.R.J.; Takes, Robert P.; Knuijt, Simone; Rooijakkers, Antoinette F.; Berg, Manon van den; Merkx, Matthias A.; Herpen, Carla M.L. van; Kaanders, Johannes H.A.M.

    2011-01-01

    Purpose: To evaluate the long-term outcome and morbidity after intensified treatment for locally advanced head-and-neck cancer. Methods and Materials: Between May 2003 and December 2007, 77 patients with Stage III to IV head-and-neck cancer were treated with curative intent. Treatment consisted of accelerated radiotherapy to a dose of 68 Gy and concurrent cisplatin. Long-term survivors were invited to a multidisciplinary outpatient clinic for a comprehensive assessment of late morbidity with special emphasis on dysphagia, including radiological evaluation of swallowing function in all patients. Results: Compliance with the treatment protocol was high, with 87% of the patients receiving at least five cycles of cisplatin and all but 1 patient completing the radiotherapy as planned. The 5-year actuarial disease-free survival and overall survival rates were 40% and 47%, respectively. Locoregional recurrence–free survival at 5 years was 61%. The 5-year actuarial rates of overall late Radiation Therapy Oncology Group (RTOG)/European Organization for Research and Treatment of Cancer (EORTC) Grade 3 and Grade 4 toxicity were 52% and 25% respectively. Radiologic evaluation after a median follow-up of 44 months demonstrated impaired swallowing in 57% of the patients, including 23% with silent aspiration. Subjective assessment using a systematic scoring system indicated normalcy of diet in only 15.6% of the patients. Conclusion: This regimen of accelerated radiotherapy with weekly cisplatin produced favorable tumor control rates and survival rates while compliance was high. However, comprehensive assessment by a multidisciplinary team of medical and paramedical specialists revealed significant long-term morbidity in the majority of the patients, with dysphagia being a major concern.

  19. Long-Term Outcome and Morbidity After Treatment With Accelerated Radiotherapy and Weekly Cisplatin for Locally Advanced Head-and-Neck Cancer: Results of a Multidisciplinary Late Morbidity Clinic

    Energy Technology Data Exchange (ETDEWEB)

    Ruetten, Heidi, E-mail: h.rutten@rther.umcn.nl [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Pop, Lucas A.M.; Janssens, Geert O.R.J. [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Takes, Robert P. [Department of Otorhinolaryngology and Head and Neck Surgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Knuijt, Simone [Department of Rehabilitation/Speech Pathology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Rooijakkers, Antoinette F. [Department of Oral and Maxillofacial Surgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Berg, Manon van den [Department of Gastroenterology-Dietetics, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Merkx, Matthias A. [Department of Oral and Maxillofacial Surgery, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Herpen, Carla M.L. van [Department of Medical Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Kaanders, Johannes H.A.M. [Department of Radiation Oncology, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands)

    2011-11-15

    Purpose: To evaluate the long-term outcome and morbidity after intensified treatment for locally advanced head-and-neck cancer. Methods and Materials: Between May 2003 and December 2007, 77 patients with Stage III to IV head-and-neck cancer were treated with curative intent. Treatment consisted of accelerated radiotherapy to a dose of 68 Gy and concurrent cisplatin. Long-term survivors were invited to a multidisciplinary outpatient clinic for a comprehensive assessment of late morbidity with special emphasis on dysphagia, including radiological evaluation of swallowing function in all patients. Results: Compliance with the treatment protocol was high, with 87% of the patients receiving at least five cycles of cisplatin and all but 1 patient completing the radiotherapy as planned. The 5-year actuarial disease-free survival and overall survival rates were 40% and 47%, respectively. Locoregional recurrence-free survival at 5 years was 61%. The 5-year actuarial rates of overall late Radiation Therapy Oncology Group (RTOG)/European Organization for Research and Treatment of Cancer (EORTC) Grade 3 and Grade 4 toxicity were 52% and 25% respectively. Radiologic evaluation after a median follow-up of 44 months demonstrated impaired swallowing in 57% of the patients, including 23% with silent aspiration. Subjective assessment using a systematic scoring system indicated normalcy of diet in only 15.6% of the patients. Conclusion: This regimen of accelerated radiotherapy with weekly cisplatin produced favorable tumor control rates and survival rates while compliance was high. However, comprehensive assessment by a multidisciplinary team of medical and paramedical specialists revealed significant long-term morbidity in the majority of the patients, with dysphagia being a major concern.

  20. Ring accelerators

    International Nuclear Information System (INIS)

    Gisler, G.; Faehl, R.

    1983-01-01

    We present two-dimensional simulations in (r-z) and r-theta) cylinderical geometries of imploding-liner-driven accelerators of rings of charged particles. We address issues of azimuthal and longitudinal stability of the rings. We discuss self-trapping designs in which beam injection and extraction is aided by means of external cusp fields. Our simulations are done with the 2-1/2-D particle-in-cell plasma simulation code CLINER, which combines collisionless, electromagnetic PIC capabilities with a quasi-MHD finite element package

  1. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  2. Cosmic ray acceleration mechanisms

    International Nuclear Information System (INIS)

    Cesarsky, C.J.

    1982-09-01

    We present a brief summary of some of the most popular theories of cosmic ray acceleration: Fermi acceleration, its application to acceleration by shocks in a scattering medium, and impulsive acceleration by relativistic shocks

  3. Industrial accelerators and their applications

    CERN Document Server

    Hamm, Marianne E

    2012-01-01

    This unique new book is a comprehensive review of the many current industrial applications of particle accelerators, written by experts in each of these fields. Readers will gain a broad understanding of the principles of these applications, the extent to which they are employed, and the accelerator technology utilized. The book also serves as a thorough introduction to these fields for non-experts and laymen. Due to the increased interest in industrial applications, there is a growing interest among accelerator physicists and many other scientists worldwide in understanding how accelerators are used in various applications. The government agencies that fund scientific research with accelerators are also seeking more information on the many commercial applications that have been or can be developed with the technology developments they are funding. Many industries are also doing more research on how they can improve their products or processes using particle beams.

  4. Accelerator operation management using objects

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, H.; Timossi, C.; Valdez, M.

    1995-04-01

    Conflicts over control of shared devices or resources in an accelerator control system, and problems that can occur due to applications performing conflicting operations, are usually resolved by accelerator operators. For these conflicts to be detected by the control system, a model of accelerator operation must be available to the system. The authors present a design for an operation management system addressing the issues of operations management using the language of Object-Oriented Design (OOD). A possible implementation using commercially available software tools is also presented.

  5. Accelerator operation management using objects

    International Nuclear Information System (INIS)

    Nishimura, H.; Timossi, C.; Valdez, M.

    1995-01-01

    Conflicts over control of shared devices or resources in an accelerator control system, and problems that can occur due to applications performing conflicting operations, are usually resolved by accelerator operators. For these conflicts to be detected by the control system, a model of accelerator operation must be available to the system. The authors present a design for an operation management system addressing the issues of operations management using the language of Object-Oriented Design (OOD). A possible implementation using commercially available software tools is also presented

  6. Heavy accelerated nuclei in biomedical research

    International Nuclear Information System (INIS)

    Tobias, C.A.

    1987-01-01

    Accelerated atomic nuclei in physics accelerators have been used in basic biological research and in applied medical diagnostic and therapeutic studies for the past 50 years. The passage of single heavy particles through the cell nucleus is capable of producing multiple DNA double-strand scission and chromatin breaks. According to the Repair-Misrepair model, the high biological effectiveness of high-LET particles is due to misrepair and misrejoining of the breaks. The Bragg depth ionization effect allows heavy particles to deposit considerably more energy deep in tissue than at the surface, and this property has been used for great improvements in the radiation therapy of localized tumors. Recent advances in producing radioactive beams will allow verification of therapeutic administration of such beams. The radioactive beams also open a new field of Nuclear Medicine. There is increasing interest in building special biomedical light and heavy-ion accelerators. These will be used not only for therapy but also for diagnosis, for the study of radiation hazards in space flight, and for basic molecular and cellular understanding of the mechanisms of radiation effect

  7. Beam profile for Malaysian electron accelerator

    International Nuclear Information System (INIS)

    Abu Bakar Ghazali; Muhamad Zahidee Taat

    2007-01-01

    This paper comprises of two calculations that require in designing a dose profile for an electron accelerator machine before its fabrication. The first is to calculate the beam deflection due to changes of high voltage (HV) supply as well as the deflection coil currents so that the electron beam will only scan at the window foil of 18 cm length and 6 cm width. Secondly, we also require to calculate the beam profile at 50 mm underneath the window foil. The electron gun that produces a beam of 10 mm diameter has to be oscillated in a sawtooth wave for the prescribed window size at frequencies of 50 Hz and 400 Hz along the length and width directions respectively. For the beam deflection, we apply a basic formula from Lorentz force law to obtain a set of HV supply and the coil current that is suitable for both deflections and this result can assist in designing the coil current against HV changes via an electronic controller. The dose profile was calculated using the RMS current formulation along the length direction. We found that the measured and the calculated RMS currents are in comparable for the case of 1 MeV, 50 mA accelerator facility that is going to be installed at Nuclear Malaysia complex. A similar measurement will be carried out for our locally designed accelerator of 150 KeV, 10 mA after fabrication and installation of the machine are completed. (Author)

  8. A locality aware convolutional neural networks accelerator

    NARCIS (Netherlands)

    Shi, R.; Xu, Z.; Sun, Z.; Peemen, M.C.J.; Li, A.; Corporaal, H.; Wu, D.

    2015-01-01

    The advantages of Convolutional Neural Networks (CNNs) with respect to traditional methods for visual pattern recognition have changed the field of machine vision. The main issue that hinders broad adoption of this technique is the massive computing workload in CNN that prevents real-time

  9. Prototype of industrial electrons accelerator

    International Nuclear Information System (INIS)

    Lopez, V.H.; Valdovinos, A.M.

    1992-01-01

    The interest and the necessity of Mexico's industry in the use of irradiation process has been increased in the last years. As examples are the irradiation of combustion gases (elimination of NO x and SO 2 ) and the polymer cross-linking between others. At present time at least twelve enterprises require immediately of them which have been contacted by electron accelerators suppliers of foreign countries. The first project step consisted in to identify the electrons accelerator type that in can be constructed in Mexico with the major number of possible equipment, instruments, components and acquisition materials local and useful for the major number of users. the characteristics of the accelerator prototype are: accelerator type transformer with multiple secondary insulated and rectifier circuits with a potential of 0.8 MV of voltage, the second step it consisted in an economic study that permitted to demonstrate the economic feasibility of its construction. (Author)

  10. Reaction effects in diffusive shock acceleration

    International Nuclear Information System (INIS)

    Drury, L.Oc.

    1984-01-01

    The effects of the reaction of accelerated particles back on the shock wave in the diffusive-shock-acceleration model of cosmic-ray generation are investigated theoretically. Effects examined include changes in the shock structure, modifications of the input and output spectra, scattering effects, and possible instabilities in the small-scale structure. It is pointed out that the latter two effects are applicable to any spatially localized acceleration mechanism. 14 references

  11. Particle acceleration by pulsars

    International Nuclear Information System (INIS)

    Arons, Jonathan.

    1980-06-01

    The evidence that pulsars accelerate relativistic particles is reviewed, with emphasis on the γ-ray observations. The current state of knowledge of acceleration in strong waves is summarized, with emphasis on the inability of consistent theories to accelerate very high energy particles without converting too much energy into high energy photons. The state of viable models for pair creation by pulsars is summarized, with the conclusion that pulsars very likely lose rotational energy in winds instead of in superluminous strong waves. The relation of the pair creation models to γ-ray observations and to soft X-ray observations of pulsars is outlined, with the conclusion that energetically viable models may exist, but none have yet yielded useful agreement with the extant data. Some paths for overcoming present problems are discussed. The relation of the favored models to cosmic rays is discussed. It is pointed out that the pairs made by the models may have observable consequences for observation of positrons in the local cosmic ray flux and for observations of the 511 keV line from the interstellar medium. Another new point is that asymmetry of plasma supply from at least one of the models may qualitatively explain the gross asymmetry of the X-ray emission from the Crab nebula. It is also argued that acceleration of cosmic ray nuclei by pulsars, while energetically possible, can occur only at the boundary of the bubbles blown by the pulsars, if the cosmic ray composition is to be anything like that of the known source spectrum

  12. Status report on the accelerators operation

    International Nuclear Information System (INIS)

    Biri, S.; Kormany, Z.; Berzi, I.; Racz, R.

    2011-01-01

    During 2011 our particle accelerators operated as scheduled, safely and without major or long breakdowns. The utilization rates of the accelerators were similar to the preceding year. The cyclotron delivered 1735 hours and the 40- years old 5 MeV Van de Graaff generator supplied more than 1900 hours. The 1 MeV Van de Graaff accelerator was also operated for several short basic physics experiments last year (84 hours) with requests for much more beamtime in 2012. The plasma and beam-on-target time at the ECR ion source was less than in previous years (322 hours) due to several time consuming technical developments in this laboratory. The isotope separator, as ion beam accelerator was utilized only for a few hours in 2011, since the research and development in this lab focused on other fields. Nevertheless it is continuously available for research requiring special deposition techniques and for isotope tracing studies. After judging and accepting the importance and quality of our accelerators and staff the title 'Strategic Research Infrastructure' was addressed to the Accelerator Center by the Hungarian authorities. In order to get access to the accelerators a new system was introduced. The beamtime (within the frames of the capacities) is available for everyone with equal chance if an acceptable scientific program is provided together with the request. The users have to contact our Program Advisory Committee (PAC). Since last year the requests - both from external or local users - must be delivered by filling out and e-sending on on-line form available in the homepage of the institute. In the next sub-chapters the 2011 operation and development details at the cyclotron, VdG-5 and ECR accelerators are summarized. Cyclotron operation. The operation of the cyclotron in 2011 was concentrated to the usual 9 months; January, July and August were reserved for maintenance and holidays. The overall working time of the accelerator was 2603 hours; the time used for systematic

  13. Sector ring accelerator ''RESATRON''

    International Nuclear Information System (INIS)

    Schwabe, E.

    1980-01-01

    Project of sector ring accelerator RESATRON is described. The curiosity of this accelerator is the second cycle of acceleration of the beam after stripping it on the foil. In such an accelerator heavy ions with a different ratio Z to A can be accelerated. (S.B.)

  14. Acceleration of particles in plasmas

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    The accelerating fields in radio-frequency accelerators are limited to roughly 100 MV/m due to material breakdown which occurs on the walls of the structure. In contrast, a plasma, being already ionized, can support electric fields in excess of 100 GV/m. Such high accelerating gradients hold the promise of compact particle accelerators. Plasma acceleration has been an emerging and fast growing field of research in the past two decades. In this series of lectures, we will review the principles of plasma acceleration. We will see how relativistic plasma waves can be excited using an ultra-intense laser or using a particle beam. We will see how these plasma waves can be used to accelerate electrons to high energy in short distances. Throughout the lectures, we will also review recent experimental results. Current laser-plasma experiments throughout the world have shown that monoenergetic electron beams from 100 MeV to 1 GeV can be obtained in distances ranging from the millimetre to the centimetre. Experiments a...

  15. Turbulence and particle acceleration

    International Nuclear Information System (INIS)

    Scott, J.S.

    1975-01-01

    A model for the production of high energy particles in the supernova remnant Cas A is considered. The ordered expansion of the fast moving knots produce turbulent cells in the ambient interstellar medium. The turbulent cells act as magnetic scattering centers and charged particles are accelerated to large energies by the second order Fermi mechanism. Model predictions are shown to be consistent with the observed shape and time dependence of the radio spectrum, and with the scale size of magnetic field irregularities. Assuming a galactic supernova rate at 1/50 yr -1 , this mechanism is capable of producing the observed galactic cosmic ray flux and spectrum below 10 16 eV/nucleon. Several observed features of galactic cosmic rays are shown to be consistent with model predictions. A model for the objects known as radio tall galaxies is also presented. Independent blobs of magnetized plasma emerging from an active radio galaxy into an intracluster medium become turbulent due to Rayleigh--Taylor and Kelvin--Helmholz instabilities. The turbulence produces both in situ betatron and 2nd order Fermi accelerations. Predictions of the dependence of spectral index and flux on distance along the tail match observations well. Fitting provides values of physical parameters in the blobs. The relevance of this method of particle acceleration for the problem of the origin of x-ray emission in clusters of galaxies is discussed

  16. Collective focusing ion accelerator

    International Nuclear Information System (INIS)

    Goldin, F.J.

    1986-01-01

    The principal subject of this dissertation is the trapping confinement of pure electron plasmas in bumpy toroidal magnetic fields, with particular attention given to the trapping procedure and the behavior of the plasma during the final equilibrium. The most important aspects of the equilibrium studied were the qualitative nature of the plasma configuration and motion and its density, distribution and stability. The motivation for this study was that an unneutralized cloud of electrons contained in a toroidal system, sufficiently dense and stable, may serve to electrostatically focus ions (against centrifugal and self space charge forces) in a cyclic ion accelerator. Such an accelerator, known as a Collective Focusing Ion Accelerator (CFIA) could be far smaller than conventional designs (which use external magnetic fields directly to focus the ions) due to the smaller gyro-radium of an electron in a magnetic field of given strength. The electron cloud generally drifted poloidally at a finite radius from the toroidal minor axis. As this would preclude focusing ions with such clouds, damping this motion was investigated. Finite resistance in the normally perfectly conductive vessel wall did this. In further preparation for a working CFIA, additional experiments studied the effect of ions on the stability of the electron cloud

  17. Multiperiodic accelerator structures for linear particle accelerators

    International Nuclear Information System (INIS)

    Tran, D.T.

    1975-01-01

    High efficiency linear accelerator structures, comprised of a succession of cylindrical resonant cavities for acceleration, are described. Coupling annular cavities are located at the periphery, each being coupled to two adjacent cylindrical cavities. (auth)

  18. IFMIF accelerators design

    International Nuclear Information System (INIS)

    Mosnier, A.; Ratzinger, U.

    2008-01-01

    The IFMIF requirement for 250 mA current of deuteron beams at a nominal energy of 40 MeV is met by means of two identical continuous wave (CW) 175 MHz linear accelerators running in parallel, each delivering a 125 mA, 40 MeV deuteron beam to the common target. This approach allows to stay within the current capability of present RF linac technology while providing operational redundancy in case of failure of one of the linacs. Each linac comprises a sequence of acceleration and beam transport/matching stages. The ion source generates a 140 mA deuteron beam at 100 keV. A low energy beam transport (LEBT) transfers the deuteron beam from the source to a radio frequency quadrupole (RFQ) cavity. The RFQ bunches and accelerates the 125 mA beam to 5 MeV. The RFQ output beam is injected through a matching section into a drift-tube-linac (DTL) where it is accelerated to the final energy of 40 MeV. In the reference design, the final acceleration stage is a conventional Alvarez-type DTL with post-couplers operating at room temperature. Operation of both the RFQ and the DTL at the same relatively low frequency is essential for accelerating the high current deuteron beam with low beam loss. The primary concern of the IFMIF linacs is the minimization of beam losses, which could limit their availability and maintainability due to excessive activation of the linac and irradiation of the environment. A careful beam dynamics design is therefore needed from the source to the target to avoid the formation of particle halo that could finally be lost in the linac or transfer lines. A superconducting solution for the high energy portion of the linac using, for example, CH-structure or coaxial-type resonators, could offer some advantages, in particular the reduction of operational costs. Careful beam dynamics simulations and comparison tests with beam during the EVEDA phase are however necessary in order to fully assess the technical feasibility of such alternative solutions

  19. Accelerators of atomic particles

    International Nuclear Information System (INIS)

    Sarancev, V.

    1975-01-01

    A brief survey is presented of accelerators and methods of accelerating elementary particles. The principle of collective accelerating of elementary particles is clarified and the problems are discussed of its realization. (B.S.)

  20. Modern control techniques for accelerators

    International Nuclear Information System (INIS)

    Goodwin, R.W.; Shea, M.F.

    1984-01-01

    Beginning in the mid to late sixties, most new accelerators were designed to include computer based control systems. Although each installation differed in detail, the technology of the sixties and early to mid seventies dictated an architecture that was essentially the same for the control systems of that era. A mini-computer was connected to the hardware and to a console. Two developments have changed the architecture of modern systems: the microprocessor and local area networks. This paper discusses these two developments and demonstrates their impact on control system design and implementation by way of describing a possible architecture for any size of accelerator. Both hardware and software aspects are included

  1. Injury due to thorotrast

    International Nuclear Information System (INIS)

    Mori, Takesaburo

    1976-01-01

    A synthetic study was performed on some of those to whom Thorotrast had been injected, in Japan. In the epidemiological study of 147 war woundeds to whom Thorotrast had been injected, it was noted that the Thorotrast injection increased the mortality rate and the incidences of malignant hepatic tumor, liver cirrhosis, and hematological diseases. Clinical study of 44 of them showed that the Thorotrast injection resulted in liver and hematopoietic hypofunctions. Analysis of the dissection of the injected area in 118 cases showed malignant hepatic tumor in 63.5%, liver cirrhosis in 14.4% and hematological diseases in 10.2%. The total of the three types of disease was 88.1%. Histological classification showed that of the malignant hepatic tumors due to Thorotrast, hepatobiliary cancer and hemangioendothelioma of the liver were frequent. By the comparison of the absorbed dose in the liver of the malignant hepatic tumors due to Thorotrast with that of the cancers developed in animal experiments, it was noted that the carcinogenic dose was a mean of 2,000 - 3,000 rad by accumulated dose. It was elucidated that carcinogenesis and fibrination were primary in injury due to Thorotrast, i.e., late injury due to Thorotrast, and that the increase in the accumulated dose in rogans and the increase of the local dose due to the gigantic growth of Thorotrast granules in organs greatly influenced carninogenesis and fibrination. (Chiba, N.)

  2. Energetic ions and electrons and their acceleration processes in the magnetotail

    International Nuclear Information System (INIS)

    Scholer, M.

    1984-01-01

    Observations of energetic particle fluxes in the geomagnetic tail show that these particles exhibit a bursty appearance on all time scales. Often, however, the bursty appearance is merely due to multiple entries and exits of the spacecraft into and out of the plasma sheet which always contains varying fluxes of energetic particles. Observations of the suprathermal and high-energy component of the plasma sheet are discussed, and observations are presented of energetic particle bursts in the plasma sheet proper, which may be due to a locally ongoing acceleration process. Also discussed are energetic particle phenomena occurring near the edge of the plasma sheet, either during thinning or during recovery. Some recent results from the ISEE 3 deep tail mission bearing on energetic particle acceleration are presented, and the present status of the theory of particle acceleration within the magnetotail is briefly reviewed. 40 references

  3. Accelerators of future generation

    International Nuclear Information System (INIS)

    Kolomenskij, A.A.

    1983-01-01

    A brief review of the prospects of development of various of types accelerator over next 10 to 15 years is given. The following directions are considered: superhign energy proton accelerators and storage rings, electron-positron colliding beams, heavy ion accelerators, medium energy, high-current proton accelerators superhigh power particle beams (electrons light- and heavy ions) for inertial fusion

  4. Future accelerator technology

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1986-05-01

    A general discussion is presented of the acceleration of particles. Upon this foundation is built a categorization scheme into which all accelerators can be placed. Special attention is devoted to accelerators which employ a wake-field mechanism and a restricting theorem is examined. It is shown how the theorem may be circumvented. Comments are made on various acceleration schemes

  5. Probing electron acceleration and x-ray emission in laser-plasma accelerators

    International Nuclear Information System (INIS)

    Thaury, C.; Ta Phuoc, K.; Corde, S.; Brijesh, P.; Lambert, G.; Malka, V.; Mangles, S. P. D.; Bloom, M. S.; Kneip, S.

    2013-01-01

    While laser-plasma accelerators have demonstrated a strong potential in the acceleration of electrons up to giga-electronvolt energies, few experimental tools for studying the acceleration physics have been developed. In this paper, we demonstrate a method for probing the acceleration process. A second laser beam, propagating perpendicular to the main beam, is focused on the gas jet few nanosecond before the main beam creates the accelerating plasma wave. This second beam is intense enough to ionize the gas and form a density depletion, which will locally inhibit the acceleration. The position of the density depletion is scanned along the interaction length to probe the electron injection and acceleration, and the betatron X-ray emission. To illustrate the potential of the method, the variation of the injection position with the plasma density is studied

  6. OpenMP for Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, J C; Stotzer, E J; Hart, A; de Supinski, B R

    2011-03-15

    OpenMP [13] is the dominant programming model for shared-memory parallelism in C, C++ and Fortran due to its easy-to-use directive-based style, portability and broad support by compiler vendors. Similar characteristics are needed for a programming model for devices such as GPUs and DSPs that are gaining popularity to accelerate compute-intensive application regions. This paper presents extensions to OpenMP that provide that programming model. Our results demonstrate that a high-level programming model can provide accelerated performance comparable to hand-coded implementations in CUDA.

  7. Chaotic dynamics in accelerator physics

    International Nuclear Information System (INIS)

    Cary, J.R.

    1992-01-01

    Substantial progress was in several areas of accelerator dynamics. For developing understanding of longitudinal adiabatic dynamics, and for creating efficiency enhancements of recirculating free-electron lasers, was substantially completed. A computer code for analyzing the critical KAM tori that bound the dynamic aperture in circular machines was developed. Studies of modes that arise due to the interaction of coating beams with a narrow-spectrum impedance have begun. During this research educational and research ties with the accelerator community at large have been strengthened

  8. Radiation monitoring around accelerator facilities

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Shinichi [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan)

    2000-07-01

    The present status of a network of radiation monitors (NORM) working at KEK is described in detail. NORM consists of there parts; stand-alone radiation monitors (SARM), local-monitoring stations (STATION) and a central data-handling system (CENTER). NORM has developed to a large-scaled monitoring system in which more than 250 SARMs are under operation for monitoring the radiation fields and radioactivities around accelerators in KEK. (author)

  9. Accelerated Creep Testing of High Strength Aramid Webbing

    Science.gov (United States)

    Jones, Thomas C.; Doggett, William R.; Stnfield, Clarence E.; Valverde, Omar

    2012-01-01

    A series of preliminary accelerated creep tests were performed on four variants of 12K and 24K lbf rated Vectran webbing to help develop an accelerated creep test methodology and analysis capability for high strength aramid webbings. The variants included pristine, aged, folded and stitched samples. This class of webbings is used in the restraint layer of habitable, inflatable space structures, for which the lifetime properties are currently not well characterized. The Stepped Isothermal Method was used to accelerate the creep life of the webbings and a novel stereo photogrammetry system was used to measure the full-field strains. A custom MATLAB code is described, and used to reduce the strain data to produce master creep curves for the test samples. Initial results show good correlation between replicates; however, it is clear that a larger number of samples are needed to build confidence in the consistency of the results. It is noted that local fiber breaks affect the creep response in a similar manner to increasing the load, thus raising the creep rate and reducing the time to creep failure. The stitched webbings produced the highest variance between replicates, due to the combination of higher local stresses and thread-on-fiber damage. Large variability in the strength of the webbings is also shown to have an impact on the range of predicted creep life.

  10. Accelerator mass analysis at tandem accelerator in Kyoto University

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Masanobu; Tazawa, Yuji; Matsumoto, Hiroshi; Hirose, Masanori [Kyoto Univ. (Japan). Faculty of Science; Ogino, Koya; Kohno, Masuchika; Funaba, Hiroyuki

    1996-12-01

    Tandem accelerator in Science Faculty, Kyoto University was renewed from 5 MV in the highest terminal voltage of Van de Graaff to 8 MV of Peletron in 1992. And, AMS effective for cosmic ray, dating, environment measurement and so forth is determined to a column of collaborative studies by universities and institutes in Japan. On this renewal, because of using high energy beam transportation of the present tandem accelerator, super high sensitivity measurement of long half-life radioactive isotopes of heavy elements such as {sup 36}Cl, {sup 41}Ca, {sup 129}I and so forth is aimed, although having some limitations due to small magnet. The accelerator is active in characteristics of the middle size tandem accelerator, and developing {sup 14}C measurement for its standard technology, as aiming at {sup 36}Cl measurement, at first. As a result, in this tandem accelerator stable and high beam transmittance could be obtained by adding a slit at negative ion source to make emittance of incident beam smaller. {sup 14}C/{sup 12}C ratio of Modan`s sample obtained by graphitizing NBS oxalic acid and Ded`s sample consisting of mineral graphite produced in Sri Lanka are measured to confirm better reproductivity of this system. Future development of successive incident method is planned to test actual carbon samples. (G.K.)

  11. An in situ Comparison of Electron Acceleration at Collisionless Shocks under Differing Upstream Magnetic Field Orientations

    Energy Technology Data Exchange (ETDEWEB)

    Masters, A.; Dougherty, M. K. [The Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Sulaiman, A. H. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Stawarz, Ł. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Reville, B. [School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Sergis, N. [Office of Space Research and Technology, Academy of Athens, Soranou Efesiou 4, 11527 Athens (Greece); Fujimoto, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Burgess, D. [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom); Coates, A. J., E-mail: a.masters@imperial.ac.uk [Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom)

    2017-07-10

    A leading explanation for the origin of Galactic cosmic rays is acceleration at high-Mach number shock waves in the collisionless plasma surrounding young supernova remnants. Evidence for this is provided by multi-wavelength non-thermal emission thought to be associated with ultrarelativistic electrons at these shocks. However, the dependence of the electron acceleration process on the orientation of the upstream magnetic field with respect to the local normal to the shock front (quasi-parallel/quasi-perpendicular) is debated. Cassini spacecraft observations at Saturn’s bow shock have revealed examples of electron acceleration under quasi-perpendicular conditions, and the first in situ evidence of electron acceleration at a quasi-parallel shock. Here we use Cassini data to make the first comparison between energy spectra of locally accelerated electrons under these differing upstream magnetic field regimes. We present data taken during a quasi-perpendicular shock crossing on 2008 March 8 and during a quasi-parallel shock crossing on 2007 February 3, highlighting that both were associated with electron acceleration to at least MeV energies. The magnetic signature of the quasi-perpendicular crossing has a relatively sharp upstream–downstream transition, and energetic electrons were detected close to the transition and immediately downstream. The magnetic transition at the quasi-parallel crossing is less clear, energetic electrons were encountered upstream and downstream, and the electron energy spectrum is harder above ∼100 keV. We discuss whether the acceleration is consistent with diffusive shock acceleration theory in each case, and suggest that the quasi-parallel spectral break is due to an energy-dependent interaction between the electrons and short, large-amplitude magnetic structures.

  12. Ion accelerator based on plasma vircator

    CERN Document Server

    Onishchenko, I N

    2001-01-01

    The conception of a collective ion accelerator is proposed to be developed in the frameworks of STCU project 1569 (NSC KIPT, Ukraine) in coordination with the ISTC project 1629 (VNIEF, Russia). The main processes of acceleration are supposed to be consisted of two stages.First one is the plasma assistance virtual cathode (VC) in which plasma ions are accelerated in a potential well of VC. Along with ion acceleration the relaxation oscillations, caused by diminishing the potential well due to ion compensation, arise that provides the low-frequency (inverse ion transit time) temporal modulation of an intense relativistic electron beam (IREB) current. At the second stage temporally modulated IREB is injected into the spatially periodic magnetic field. The further ion acceleration is realized by the slow space charge wave that arises in IREB due to its simultaneous temporal and spatial modulation.

  13. 2014 CERN Accelerator Schools: Plasma Wake Acceleration

    CERN Multimedia

    2014-01-01

    A specialised school on Plasma Wake Acceleration will be held at CERN, Switzerland from 23-29 November, 2014.   This course will be of interest to staff and students in accelerator laboratories, university departments and companies working in or having an interest in the field of new acceleration techniques. Following introductory lectures on plasma and laser physics, the course will cover the different components of a plasma wake accelerator and plasma beam systems. An overview of the experimental studies, diagnostic tools and state of the art wake acceleration facilities, both present and planned, will complement the theoretical part. Topical seminars and a visit of CERN will complete the programme. Further information can be found at: http://cas.web.cern.ch/cas/PlasmaWake2014/CERN-advert.html http://indico.cern.ch/event/285444/

  14. ETA-II accelerator upgrades

    International Nuclear Information System (INIS)

    Nilson, D.G.; Deadrick, F.J.; Hibbs, S.M.; Sampayan, S.E.; Petersen, D.E.

    1991-09-01

    We discuss recent improvements to the ETA-II linear induction electron accelerator. The accelerator's cells have been carefully reconditioned to raise the maximum accelerating gap voltage from approximately 100 kV to 125 kV. Insulators of Rexolite plastic in a new ''zero-gap'' arrangement replaced the alumina originals after several alternative materials were investigated. A new multi-cable current feed system will be used to eliminate pulse reflection interactions encountered in earlier experiments. Improved alignment fixtures have been installed to help minimize beam perturbation due to poorly aligned intercell magnets between 10-cell groups. A stretched wire alignment technique (SWAT) has been utilized to enhance overall magnetic alignment, and to characterize irreducible alignment errors. These changes are in conjunction with an expansion of the accelerator from a 20-cell to a 60-cell configuration. When completed, the upgraded accelerator is expected to deliver 2.5 kA of electron beam current at 7.5 MeV in bursts of up to fifty 70-ns pulses at a 5-kHz repetition rate. A 5.5-meter-long wiggler will convert the energy into 3-GW microwave pulses at 140 GHz for plasma heating experiments in the Microwave Tokamak Experiment (MTX)

  15. In situ acceleration in extragalactic radio jets

    International Nuclear Information System (INIS)

    Bicknell, G.V.; Melrose, D.B.

    1982-01-01

    We have examined the energy dissipated by large-scale turbulence in an extragalactic jet. The turbulence is driven by a shear instability which does not disrupt the jet. Fluid theory should be used to treat the evolution of the turbulence, and this allows us to estimate the rate of dissipation without detailed knowledge of the dissipation process. Dissipation occurs due to Fermi acceleration at a scale length approx.10 -3 R and that resonant acceleration plays no role. The Alfvenic component in the turbulent spectrum is dissipated by first being converted into magneto-acoustic waves. An alternative dissipation process due to formation of weak shocks is shown to be equivalent in some respects to Fermi acceleration. Dissipation in the thermal gas should not exceed that due to Fermi acceleration. The effect of Fermi acceleration, adiabatic losses, and radiative losses on an initial power-law distribution with an upper cutoff is studied. Radio emission extending to at least 100 GHz is shown to be possible, and no spectral index gradients are introduced by the acceleration. The upper cutoff can increase due to the acceleration alone or when the acceleration is balanced by radiative losses. The northern jet in NGC 315 is studied in detail. Using our model for the acceleration, we estimate a jet velocity > or approx. =5000 km s -1 with Mach number not much greater than 1, and a density -4 f -1 cm -3 at the turn-on of the jet at 6 cm, where 0.05 5 yr, and it is predicted that the radius of the jet at the turn-on point should vary with frequency either as ν/sup 2/3/ or as ν/sup 3/2/, or there may be no frequency dependence, contingent upon the details of the acceleration

  16. The spinning disc: studying radial acceleration and its damping process with smartphone acceleration sensors

    Science.gov (United States)

    Hochberg, K.; Gröber, S.; Kuhn, J.; Müller, A.

    2014-03-01

    Here, we show the possibility of analysing circular motion and acceleration using the acceleration sensors of smartphones. For instance, the known linear dependence of the radial acceleration on the distance to the centre (a constant angular frequency) can be shown using multiple smartphones attached to a revolving disc. As a second example, the decrease of the radial acceleration and the rotation frequency due to friction can be measured and fitted with a quadratic function, in accordance with theory. Finally, because the disc is not set up exactly horizontal, each smartphone measures a component of the gravitational acceleration that adds to the radial acceleration during one half of the period and subtracts from the radial acceleration during the other half. Hence, every graph shows a small modulation, which can be used to determine the rotation frequency, thus converting a ‘nuisance effect’ into a source of useful information, making additional measurements with stopwatches or the like unnecessary.

  17. Accelerated Electron-Beam Formation with a High Capture Coefficient in a Parallel Coupled Accelerating Structure

    Science.gov (United States)

    Chernousov, Yu. D.; Shebolaev, I. V.; Ikryanov, I. M.

    2018-01-01

    An electron beam with a high (close to 100%) coefficient of electron capture into the regime of acceleration has been obtained in a linear electron accelerator based on a parallel coupled slow-wave structure, electron gun with microwave-controlled injection current, and permanent-magnet beam-focusing system. The high capture coefficient was due to the properties of the accelerating structure, beam-focusing system, and electron-injection system. Main characteristics of the proposed systems are presented.

  18. Other people's accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-06-15

    The first report from the Washington Accelerator Conference concentrated on news from the particle physics centres. But the bulk of the Conference covered the use of accelerators in other fields, underlining this valuable spinoff from particle physics.

  19. Improved plasma accelerator

    Science.gov (United States)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  20. The electron accelerator Ridgetron

    International Nuclear Information System (INIS)

    Hayashizaki, N.; Hattori, T.; Odera, M.; Fujisawa, T.

    1999-01-01

    Many electron accelerators of DC or RF type have been widely used for electron beam irradiation (curing, crosslinking of polymers, sterilization of medical disposables, preservation of food, etc.). Regardless of the acceleration energy, the accelerators to be installed in industrial facilities, have to satisfy the requires of compact size, low power consumption and stable operation. The DC accelerator is realized very compact in the energy under 300 keV, however, it is large to prevent the discharge of an acceleration column in the energy over 300 keV. The RF electron accelerator Ridgetron has been developed to accelerate the continuous beam of the 0.5-10 MeV range in compact space. It is the first example as an electron accelerator incorporated a ridged RF cavity. A prototype system of final energy of 2.5 MeV has been studied to confirm the feasibility at present

  1. High brightness electron accelerator

    International Nuclear Information System (INIS)

    Sheffield, R.L.; Carlsten, B.E.; Young, L.M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of accelerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electrons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electrons as the electrons enter the first cavity. 5 figs

  2. Unified accelerator libraries

    International Nuclear Information System (INIS)

    Malitsky, Nikolay; Talman, Richard

    1997-01-01

    A 'Universal Accelerator Libraries' (UAL) environment is described. Its purpose is to facilitate program modularity and inter-program and inter-process communication among heterogeneous programs. The goal ultimately is to facilitate model-based control of accelerators

  3. YEREVAN: Acceleration workshop

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Sponsored by the Yerevan Physics Institute in Armenia, a Workshop on New Methods of Charged Particle Acceleration in October near the Nor Amberd Cosmic Ray Station attracted participants from most major accelerator centres in the USSR and further afield

  4. San Francisco Accelerator Conference

    International Nuclear Information System (INIS)

    Southworth, Brian

    1991-01-01

    'Where are today's challenges in accelerator physics?' was the theme of the open session at the San Francisco meeting, the largest ever gathering of accelerator physicists and engineers

  5. Large tandem accelerators

    International Nuclear Information System (INIS)

    Jones, C.M.

    1976-01-01

    The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of tandem accelerators designed to operate at maximum terminal potentials in the range 14 to 30 MV. In addition, a number of older tandem accelerators are now being significantly upgraded to improve their heavy ion performance. Both of these developments have reemphasized the importance of negative heavy ion sources. The new large tandem accelerators are described, and the requirements placed on negative heavy ion source technology by these and other tandem accelerators used for the acceleration of heavy ions are discussed. First, a brief description is given of the large tandem accelerators which have been completed recently, are under construction, or are funded for construction, second, the motivation for construction of these accelerators is discussed, and last, criteria for negative ion sources for use with these accelerators are presented

  6. Vp x B acceleration

    International Nuclear Information System (INIS)

    Sugihara, Ryo.

    1987-05-01

    A unique particle acceleration by an electrostatic (ES) wave, a magnetosonic shock wave as well as an electromagnetic (EM) wave is reviewed. The principle of the acceleration is that when a charged particle is carried across an external magnetic field the charge feels a DC field (the Lorentz force) and is accelerated. The theory for the ES wave acceleration is experimentally verified thought it is semi-quantitative. The shock acceleration is extensively studied theoretically and in a particle simulation method and the application is extended to phenomena in interplanetary space. The EM wave acceleration is based on a trapping in a moving neutral sheet created by the wave magnetic field and the external magnetic field, and the particle can be accelerated indefinitely. A brief sketch on a slow-wave-structure for this acceleration will be given. (author)

  7. Accelerator-timing system

    International Nuclear Information System (INIS)

    Timmer, E.; Heine, E.

    1985-01-01

    Along the NIKHEF accelerator in Amsterdam (Netherlands), at several places a signal is needed for the sychronisation of all devices with the acceleration process. In this report, basic principles and arrangements of this timing system are described

  8. Linear accelerator: A concept

    Science.gov (United States)

    Mutzberg, J.

    1972-01-01

    Design is proposed for inexpensive accelerometer which would work by applying pressure to fluid during acceleration. Pressure is used to move shuttle, and shuttle movement is sensed and calibrated to give acceleration readings.

  9. Heavy ion accelerators

    International Nuclear Information System (INIS)

    Schmelzer, C.

    1974-01-01

    This review of the present state of work on heavy-ion accelerators pays particular attention to the requirements for nuclear research. It is divided into the following sections: single-particle versus collective acceleration, heavy-ion accelerators, beam quality, and a status report on the UNILAC facility. Among the topics considered are the recycling cyclotron, linacs with superconducting resonators, and acceleration to the GeV/nucleon range. (8 figures, 2 tables) (U.S.)

  10. Accelerators at school

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Latest subject covered by the CERN Accelerator School was 'Applied Geodesy of Particle Accelerators', which attracted an impressive number of outside participants to CERN for a week in April. Since the forerunners of today's particle accelerators were demonstrated over 50 years ago, the positioning of accelerator components has progressed from the laboratory bench-top to tunnels tens of kilometres long. Despite this phenomenal growth in size, sub-millimetre accuracy is still required

  11. Accelerators at school

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-06-15

    Latest subject covered by the CERN Accelerator School was 'Applied Geodesy of Particle Accelerators', which attracted an impressive number of outside participants to CERN for a week in April. Since the forerunners of today's particle accelerators were demonstrated over 50 years ago, the positioning of accelerator components has progressed from the laboratory bench-top to tunnels tens of kilometres long. Despite this phenomenal growth in size, sub-millimetre accuracy is still required.

  12. Accelerators for Medicine

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    This lecture will review the different applications of particle accelerators to the medical field, from cancer treatment with beams of accelerator-produced particles (photons, electrons, protons, ions and neutrons) to the generation of radioactive isotopes used in medical diagnostics, in cancer therapy and in the new domain of theragnostics. For each application will be outlined the state of the art, the potential, and the accelerator challenges to be faced to meet the increasing demand for therapeutic procedures based on accelerators.

  13. Large electrostatic accelerators

    International Nuclear Information System (INIS)

    Jones, C.M.

    1984-01-01

    The paper is divided into four parts: a discussion of the motivation for the construction of large electrostatic accelerators, a description and discussion of several large electrostatic accelerators which have been recently completed or are under construction, a description of several recent innovations which may be expected to improve the performance of large electrostatic accelerators in the future, and a description of an innovative new large electrostatic accelerator whose construction is scheduled to begin next year

  14. Particle beam accelerator

    International Nuclear Information System (INIS)

    Turner, N.L.

    1982-01-01

    A particle beam accelerator is described which has several electrodes that are selectively short circuited together synchronously with changes in the magnitude of a DC voltage applied to the accelerator. By this method a substantially constant voltage gradient is maintained along the length of the unshortened electrodes despite variations in the energy applied to the beam by the accelerator. The invention has particular application to accelerating ion beams that are implanted into semiconductor wafers. (U.K.)

  15. Superconducting accelerator technology

    International Nuclear Information System (INIS)

    Grunder, H.A.; Hartline, B.K.

    1986-01-01

    Modern and future accelerators for high energy and nuclear physics rely increasingly on superconducting components to achieve the required magnetic fields and accelerating fields. This paper presents a practical overview of the phenomenon of superconductivity, and describes the design issues and solutions associated with superconducting magnets and superconducting rf acceleration structures. Further development and application of superconducting components promises increased accelerator performance at reduced electric power cost

  16. Applications of particle accelerators

    International Nuclear Information System (INIS)

    Barbalat, O.

    1994-01-01

    Particle accelerators are now widely used in a variety of applications for scientific research, applied physics, medicine, industrial processing, while possible utilisation in power engineering is envisaged. Earlier presentations of this subject, given at previous CERN Accelerator School sessions have been updated with papers contributed to the first European Conference on Accelerators in Applied Research and Technology (ECAART) held in September 1989 in Frankfurt and to the Second European Particle Accelerator Conference in Nice in June 1990. (orig.)

  17. The CERN Accelerator School

    CERN Multimedia

    2016-01-01

    Introduction to accelerator physics The CERN Accelerator School: Introduction to Accelerator Physics, which should have taken place in Istanbul, Turkey, later this year has now been relocated to Budapest, Hungary.  Further details regarding the new hotel and dates will be made available as soon as possible on a new Indico site at the end of May.

  18. Accelerators and Dinosaurs

    CERN Multimedia

    Turner, Michael Stanley

    2003-01-01

    Using naturally occuring particles on which to research might have made accelerators become extinct. But in fact, results from astrophysics have made accelerator physics even more important. Not only are accelerators used in hospitals but they are also being used to understand nature's inner workings by searching for Higgs bosons, CP violation, neutrino mass and dark matter (2 pages)

  19. Far field acceleration

    International Nuclear Information System (INIS)

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail

  20. Accelerated carbonation testing of mortar with supplementary cement materials. Limitation of the acceleration due to drying

    NARCIS (Netherlands)

    Visser, J.H.M.

    2012-01-01

    In the design stage of a concrete structure, decisions have to be made on how to fulfil the required service life and consequently, what concrete composition to use. Concrete compositions can be chosen on account of known performances but this will limit the choice of compositions and materials to

  1. Quantum effects in accelerator physics

    International Nuclear Information System (INIS)

    Leinaas, J.M.

    1991-08-01

    Quantum effects for electrons in a storage ring are discussed, in particular the polarization effect due to spin flip synchrotron radiation. The electrons are treated as a simple quantum mechnical two-level system coupled to the orbital motion and the radiation field. The excitations of the spin system are then related to the Unruh effect, i.e. the effect that an accelerated radiation detector is thermally excited by vacuum fluctuations. 24 refs., 2 figs

  2. Diamond coating in accelerator structure

    International Nuclear Information System (INIS)

    Lin, X.E.

    1998-08-01

    The future accelerators with 1 GeV/m gradient will give rise to hundreds of degrees instantaneous temperature rise on the copper surface. Due to its extraordinary thermal and electric properties, diamond coating on the surface is suggested to remedy this problem. Multi-layer structure, with the promise of even more temperature reduction, is also discussed, and a proof of principle experiment is being carried out

  3. Virtual Accelerator for Accelerator Optics Improvement

    CERN Document Server

    Yan Yi Ton; Decker, Franz Josef; Ecklund, Stanley; Irwin, John; Seeman, John; Sullivan, Michael K; Turner, J L; Wienands, Ulrich

    2005-01-01

    Through determination of all quadrupole strengths and sextupole feed-downs by fitting quantities derivable from precision orbit measurement, one can establish a virtual accelerator that matches the real accelerator optics. These quantities (the phase advances, the Green's functions, and the coupling eigen-plane ellipses tilt angles and axis ratios) are obtained by analyzing turn-by-turn Beam Position Monitor (BPM) data with a model-independent analysis (MIA). Instead of trying to identify magnet errors, a limited number of quadrupoles are chosen for optimized strength adjustment to improve the virtual accelerator optics and then applied to the real accelerator accordingly. These processes have been successfully applied to PEP-II rings for beta beating fixes, phase and working tune adjustments, and linear coupling reduction to improve PEP-II luminosity.

  4. The Accelerator Reliability Forum

    CERN Document Server

    Lüdeke, Andreas; Giachino, R

    2014-01-01

    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  5. Notes on Laser Acceleration

    International Nuclear Information System (INIS)

    Tajima, T.

    2008-01-01

    This note intends to motivate our effort toward the advent of new methods of particle acceleration, utilizing the fast rising laser technology. By illustrating the underlying principles in an intuitive manner and thus less jargon-clad fashion, we seek a direction in which we shall be able to properly control and harness the promise of laser acceleration. First we review the idea behind the laser wakefield. We then go on to examine ion acceleration by laser. We examine the sheath acceleration in particular and look for the future direction that allows orderly acceleration of ions in high energies

  6. Industrial Application of Accelerators

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    At CERN, we are very familiar with large, high energy particle accelerators. However, in the world outside CERN, there are more than 35000 accelerators which are used for applications ranging from treating cancer, through making better electronics to removing harmful micro-organisms from food and water. These are responsible for around $0.5T of commerce each year. Almost all are less than 20 MeV and most use accelerator types that are somewhat different from what is at CERN. These lectures will describe some of the most common applications, some of the newer applications in development and the accelerator technology used for them. It will also show examples of where technology developed for particle physics is now being studied for these applications. Rob Edgecock is a Professor of Accelerator Science, with a particular interest in the medical applications of accelerators. He works jointly for the STFC Rutherford Appleton Laboratory and the International Institute for Accelerator Applications at the Univer...

  7. Industrial Application of Accelerators

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    At CERN, we are very familiar with large, high energy particle accelerators. However, in the world outside CERN, there are more than 35000 accelerators which are used for applications ranging from treating cancer, through making better electronics to removing harmful micro-organisms from food and water. These are responsible for around $0.5T of commerce each year. Almost all are less than 20 MeV and most use accelerator types that are somewhat different from what is at CERN. These lectures will describe some of the most common applications, some of the newer applications in development and the accelerator technology used for them. It will also show examples of where technology developed for particle physics is now being studied for these applications. Rob Edgecock is a Professor of Accelerator Science, with a particular interest in the medical applications of accelerators. He works jointly for the STFC Rutherford Appleton Laboratory and the International Institute for Accelerator Applications at the Uni...

  8. Accelerations in Flight

    Science.gov (United States)

    Doolittle, J H

    1925-01-01

    This work on accelerometry was done at McCook Field for the purpose of continuing the work done by other investigators and obtaining the accelerations which occur when a high-speed pursuit airplane is subjected to the more common maneuvers. The accelerations obtained in suddenly pulling out of a dive with well-balanced elevators are shown to be within 3 or 4 per cent of the theoretically possible accelerations. The maximum acceleration which a pilot can withstand depends upon the length of time the acceleration is continued. It is shown that he experiences no difficulty under the instantaneous accelerations as high as 7.8 G., but when under accelerations in excess of 4.5 G., continued for several seconds, he quickly loses his faculties.

  9. Accelerators for energy

    International Nuclear Information System (INIS)

    Inoue, Makoto

    2000-01-01

    A particle accelerator is a device to consume energy but not to produce it. Then, the titled accelerator seems to mean an accelerator for using devices related to nuclear energy. For an accelerator combined to nuclear fissionable fuel, neutron sources are D-T type, (gamma, n) reaction using electron beam type spallation type, and so forth. At viewpoints of powers of incident beam and formed neutron, a spallation type source using high energy proton is told to be effective but others have some advantages by investigation on easy operability, easy construction, combustion with target, energy and directivity of neutron, and so forth. Here were discussed on an accelerator for research on accelerator driven energy system by dividing its researching steps, and on kind, energy, beam intensity, and so forth of an accelerator suitable for it. And, space electric charge effect at beam propagation direction controlled by beam intensity of cyclotron was also commented. (G.K.)

  10. Modern control techniques for accelerators

    International Nuclear Information System (INIS)

    Goodwin, R.W.; Shea, M.F.

    1984-05-01

    Beginning in the mid to late sixties, most new accelerators were designed to include computer based control systems. Although each installation differed in detail, the technology of the sixties and early to mid seventies dictated an architecture that was essentially the same for the control systems of that era. A mini-computer was connected to the hardware and to a console. Two developments have changed the architecture of modern systems: (a) the microprocessor and (b) local area networks. This paper discusses these two developments and demonstrates their impact on control system design and implementation by way of describing a possible architecture for any size of accelerator. Both hardware and software aspects are included

  11. Implementation of Hardware Accelerators on Zynq

    DEFF Research Database (Denmark)

    Toft, Jakob Kenn

    of the ARM Cortex-9 processor featured on the Zynq SoC, with regard to execution time, power dissipation and energy consumption. The implementation of the hardware accelerators were successful. Use of the Monte Carlo processor resulted in a significant increase in performance. The Telco hardware accelerator......In the recent years it has become obvious that the performance of general purpose processors are having trouble meeting the requirements of high performance computing applications of today. This is partly due to the relatively high power consumption, compared to the performance, of general purpose...... processors, which has made hardware accelerators an essential part of several datacentres and the worlds fastest super-computers. In this work, two different hardware accelerators were implemented on a Xilinx Zynq SoC platform mounted on the ZedBoard platform. The two accelerators are based on two different...

  12. An introduction to acceleration mechanisms

    International Nuclear Information System (INIS)

    Palmer, R.B.

    1987-05-01

    This paper discusses the acceleration of charged particles by electromagnetic fields, i.e., by fields that are produced by the motion of other charged particles driven by some power source. The mechanisms that are discussed include: Ponderamotive Forces, Acceleration, Plasma Beat Wave Acceleration, Inverse Free Electron Laser Acceleration, Inverse Cerenkov Acceleration, Gravity Acceleration, 2D Linac Acceleration and Conventional Iris Loaded Linac Structure Acceleration

  13. Status of JAERI tandem accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tadashi; Kanda, Susumu; Takeuchi, Suehiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] (and others)

    2001-02-01

    JAERI Tandem Accelerator had been operated approximately 230 days in fiscal year of 1999. Meanwhile, we had three times of maintenance period with vent. Total operation-times were 5273 hours. We could not carry out the experiment using rare gas, due to malfunction of the RF power supply for the ECR ion source. The type of the RF power supply is peculiar and it is impossible to get spare parts for repair. We are now investigating the backup RF power supply. The power supply for the magnet became unstable due to degradation of insulation in the shunt resistance, which is used for feedback stabilization. Stability was recovered after cleaning. The acrylic resin shaft was cracked. This cracks have a potential for severe accidents. So far bearing of the shaft has no problem. The reason of cracks may be self-destruction by charge accumulation in the shaft. JAERI Tandem Accelerator is approximately 20 years old. There appear requirements on the higher ion currents for additional ion species. Therefore, authors are investigating cost effective improvement plans of RFQ (Radio Frequency Quadra-pole) and IH type accelerator based on KEK (High Energy Accelerator Research Organization) R and D. As a whole, maintenance services for the control system are increasing due to some changes of computer programs. There are some difficulties to keep skilled personnel for facilities operation. Authors are gradually increasing hired personnel with contract from 1993. However, loads for JAERI permanent staffs are still heavy. It takes much longer time to educate skilled persons especially for safety. (Y. Tanaka)

  14. Accelerator and radiation physics

    CERN Document Server

    Basu, Samita; Nandy, Maitreyee

    2013-01-01

    "Accelerator and radiation physics" encompasses radiation shielding design and strategies for hadron therapy accelerators, neutron facilities and laser based accelerators. A fascinating article describes detailed transport theory and its application to radiation transport. Detailed information on planning and design of a very high energy proton accelerator can be obtained from the article on radiological safety of J-PARC. Besides safety for proton accelerators, the book provides information on radiological safety issues for electron synchrotron and prevention and preparedness for radiological emergencies. Different methods for neutron dosimetry including LET based monitoring, time of flight spectrometry, track detectors are documented alongwith newly measured experimental data on radiation interaction with dyes, polymers, bones and other materials. Design of deuteron accelerator, shielding in beam line hutches in synchrotron and 14 MeV neutron generator, various radiation detection methods, their characteriza...

  15. 2014 Accelerators meeting, Grenoble

    International Nuclear Information System (INIS)

    Lucotte, Arnaud; Lamy, Thierry; De Conto, Jean-Marie; Fontaine, Alain; Revol, Jean-Luc; Nadolski, Laurent S.; Kazamias, Sophie; Vretenar, Maurizio; Ferrando, Philippe; Laune, Bernard; Vedrine, Pierre

    2014-10-01

    The Accelerators meeting is organised every two years by the Accelerators division of the French Society of Physics (SFP). It brings together about 50 participants during a one-day meeting. The morning sessions are devoted to scientific presentations while the afternoon is dedicated to technical visits of facilities. This document brings together the available presentations (slides): 1 - Presentation of the Laboratory of subatomic physics and cosmology - LPSC-Grenoble (Lucotte, Arnaud; Lamy, Thierry); 2 - Presentation of the Accelerators division of the French Society of Physics (Fontaine, Alain; Revol, Jean-Luc); 3 - Presentation of Grenoble's master diplomas in Accelerator physics (Nadolski, Laurent S.); 4 - Presentation of Paris' master diplomas in big instruments (Kazamias, Sophie); 5 - Particle accelerators and European Union's projects (Vretenar, Maurizio); 6 - French research infrastructures (Ferrando, Philippe); 7 - Coordination of accelerators activity in France (Laune, Bernard; Vedrine, Pierre)

  16. Accelerator reliability workshop

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, L; Duru, Ph; Koch, J M; Revol, J L; Van Vaerenbergh, P; Volpe, A M; Clugnet, K; Dely, A; Goodhew, D

    2002-07-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop.

  17. Accelerator reliability workshop

    International Nuclear Information System (INIS)

    Hardy, L.; Duru, Ph.; Koch, J.M.; Revol, J.L.; Van Vaerenbergh, P.; Volpe, A.M.; Clugnet, K.; Dely, A.; Goodhew, D.

    2002-01-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop

  18. Acceleration of radioactive ions

    International Nuclear Information System (INIS)

    Laxdal, R.E.

    2003-01-01

    There is an intense interest world-wide in the use of radioactive ion beams (RIBs) for experiment. In many existing or proposed facilities ions are produced or collected at source potential, ionized and re-accelerated. Within the past year three new ISOL based facilities have added dedicated post-accelerators to deliver accelerated RIBs to experiment. The paper gives an overview of RIB accelerators present and future, and explores the inherent features in the various acceleration methods with an emphasis on heavy ion linacs. The ISAC-I and ISAC-II post-accelerators are discussed as examples. Commissioning results and initial operating experience with ISAC-I will be presented

  19. Nuclear physics accelerator facilities

    International Nuclear Information System (INIS)

    1988-12-01

    This paper describes many of the nuclear physics heavy-ion accelerator facilities in the US and the research programs being conducted. The accelerators described are: Argonne National Laboratory--ATLAS; Brookhaven National Laboratory--Tandem/AGS Heavy Ion Facility; Brookhaven National Laboratory--Relativistic Heavy Ion Collider (RHIC) (Proposed); Continuous Electron Beam Accelerator Facility; Lawrence Berkeley Laboratory--Bevalac; Lawrence Berkeley Laboratory--88-Inch Cyclotron; Los Alamos National Laboratory--Clinton P. Anderson Meson Physics Facility (LAMPF); Massachusetts Institute of Technology--Bates Linear Accelerator Center; Oak Ridge National Laboratory--Holifield Heavy Ion Research Facility; Oak Ridge National Laboratory--Oak Ridge Electron Linear Accelerator; Stanford Linear Accelerator Center--Nuclear Physics Injector; Texas AandM University--Texas AandM Cyclotron; Triangle Universities Nuclear Laboratory (TUNL); University of Washington--Tandem/Superconducting Booster; and Yale University--Tandem Van de Graaff

  20. Advanced Accelerator Test Facility (AATF) upgrade plan

    International Nuclear Information System (INIS)

    Gai, W.; Ho, C.; Konecny, R.

    1989-01-01

    We have successfully demonstrated the principles of wake-field acceleration using structures (cavity, dielectric) and plasmas as wake-field devices using the AATF at Argonne National Laboratory. Due to the limited driver electron pulse intensity and relative long pulse length, only modest accelerating gradients were observed. In order to study the wake field effects in much greater detail and demonstrate the feasibility of wake-field accelerator for high energy physics, we are considering construction of a laser photocathode injector on the existing 20 MeV Chem-Linac to produce very intense and short electron pulses. 10 refs., 5 figs

  1. Transmutation of fission products through accelerator

    International Nuclear Information System (INIS)

    Nakamura, H.; Tani, S.; Takahashi, T.; Yamamura, O.

    1995-01-01

    The transmutation of fission products through particle accelerators has been studied under the OMEGA program. The photonuclear reaction has also been investigated to be applied to transmuting long-lived fission products, such as Cesium and Strontium, which have difficulties on reaction with neutrons due to its so small cross section. It is applicable for the transmutation if the energy balance can be improved with a monochromatic gamma rays in the range of the Giant Dipole Resonance generated through an excellent high current electron linear accelerator. The feasibility studies are being conducted on the transmutation system using it through an electron accelerator. (authors)

  2. Statistical analysis of the acceleration of Baltic mean sea-level rise, 1900-2012

    Directory of Open Access Journals (Sweden)

    Birgit Hünicke

    2016-07-01

    Full Text Available We analyse annual mean sea-level records from tide-gauges located in the Baltic and parts of the North Sea with the aim of detecting an acceleration of sea-level rise over the 20textsuperscript{th} and 21textsuperscript{st} centuries. The acceleration is estimated as a (1 fit to a polynomial of order two in time, (2 a long-term linear increase in the rates computed over gliding overlapping decadal time segments, and (3 a long-term increase of the annual increments of sea level.The estimation methods (1 and (2 prove to be more powerful in detecting acceleration when tested with sea-level records produced in global climate model simulations. These methods applied to the Baltic-Sea tide-gauges are, however, not powerful enough to detect a significant acceleration in most of individual records, although most estimated accelerations are positive. This lack of detection of statistically significant acceleration at the individual tide-gauge level can be due to the high-level of local noise and not necessarily to the absence of acceleration.The estimated accelerations tend to be stronger in the north and east of the Baltic Sea. Two hypothesis to explain this spatial pattern have been explored. One is that this pattern reflects the slow-down of the Glacial Isostatic Adjustment. However, a simple estimation of this effect suggests that this slow-down cannot explain the estimated acceleration. The second hypothesis is related to the diminishing sea-ice cover over the 20textsuperscript{th} century. The melting o of less saline and colder sea-ice can lead to changes in sea-level. Also, the melting of sea-ice can reduce the number of missing values in the tide-gauge records in winter, potentially influencing the estimated trends and acceleration of seasonal mean sea-level This hypothesis cannot be ascertained either since the spatial pattern of acceleration computed for winter and summer separately are very similar. The all-station-average-record displays an

  3. Unlimited ion acceleration by radiation pressure.

    Science.gov (United States)

    Bulanov, S V; Echkina, E Yu; Esirkepov, T Zh; Inovenkov, I N; Kando, M; Pegoraro, F; Korn, G

    2010-04-02

    The energy of ions accelerated by an intense electromagnetic wave in the radiation pressure dominated regime can be greatly enhanced due to a transverse expansion of a thin target. The expansion decreases the number of accelerated ions in the irradiated region resulting in an increase in the ion energy and in the ion longitudinal velocity. In the relativistic limit, the ions become phase locked with respect to the electromagnetic wave resulting in unlimited ion energy gain.

  4. Current status of accelerator-based boron neutron capture therapy

    International Nuclear Information System (INIS)

    Kreiner, A. J.; Bergueiro, J.; Di Paolo, H.; Castell, W.; Vento, V. Thatar; Cartelli, D.; Kesque, J.M.; Valda, A.A.; Ilardo, J.C.; Baldo, M.; Erhardt, J.; Debray, M.E.; Somacal, H.R.; Estrada, L.; Sandin, J.C. Suarez; Igarzabal, M.; Huck, H.; Padulo, J.; Minsky, D.M.

    2011-01-01

    The direct use of proton and heavy ion beams for radiotherapy is a well established cancer treatment modality, which is becoming increasingly widespread due to its clear advantages over conventional photon-based treatments. This strategy is suitable when the tumor is spatially well localized. Also the use of neutrons has a long tradition. Here Boron Neutron Capture Therapy (BNCT) stands out, though on a much smaller scale, being a second-generation promising alternative for tumors which are diffuse and infiltrating. On this sector, so far only nuclear reactors have been used as neutron sources. In this paper we describe the current situation worldwide as far as the use of accelerator-based neutron sources for BNCT is concerned (so-called Accelerator-Based (AB)-BNCT). In particular we discuss the present status of an ongoing project to develop a folded Tandem-ElectroStatic-Quadrupole (TESQ) accelerator at the Atomic Energy Commission of Argentina. The project goal is a machine capable of delivering 30 mA of 2.4 MeV protons to be used in conjunction with a neutron production target based on the 7 Li(p,n) 7 Be reaction. These are the specifications needed to produce sufficiently intense and clean epithermal neutron beams to perform BNCT for deep-seated tumors in less than an hour. (author)

  5. Characteristics of diffusion flames with accelerated motion

    Directory of Open Access Journals (Sweden)

    Lou Bo

    2016-01-01

    Full Text Available The aim of this work is to present an experiment to study the characteristics of a laminar diffusion flame under acceleration. A Bunsen burner (nozzle diameter 8 mm, using liquefied petroleum gas as its fuel, was ignited under acceleration. The temperature field and the diffusion flame angle of inclination were visualised with the assistance of the visual display technology incorporated in MATLAB™. Results show that the 2-d temperature field under different accelerations matched the variation in average temperatures: they both experience three variations at different time and velocity stages. The greater acceleration has a faster change in average temperature with time, due to the accumulation of combustion heat: the smaller acceleration has a higher average temperature at the same speed. No matter what acceleration was used, in time, the flame angle of inclination increased, but the growth rate decreased until an angle of 90°: this could be explained by analysis of the force distribution within the flame. It is also found that, initially, the growth rate of angle with velocity under the greater acceleration was always smaller than that at lower accelerations; it was also different in flames with uniform velocity fire conditions.

  6. Unified 1.9...4.0 MeV linear accelerators with interchangeable accelerating structures for customs inspection

    International Nuclear Information System (INIS)

    Budtov, A.A.; Klinov, A.P.; Krestianinov, A.S.

    2004-01-01

    A series of compact linear electron accelerators for 1.9, 2.5 and 4.0 MeV equipped with a local radiation shielding has been designed and constructed in the NPK LUTS, the D.V.Efremov Institute (NIIEFA). The accelerators are intended for mobile facilities used for customs inspection of large-scale containers. Results of optimizing calculations of irradiator parameters and electron dynamics, verified under accelerators testing, are presented in the report. The main design approaches allowing the construction of unified accelerators with interchangeable accelerating structures for energies in the range of 1.9...4.0 MeV are also given

  7. Japan Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    At the international level, the high energy accelerator scene evolves rapidly and the International Conference on High Energy Accelerators is where its strong pulse can best be felt. This year, the Conference was held for the first time in Japan, with the 14th meeting in the series having been hosted in August by the Japanese KEK National Laboratory for High Energy Physics, Tsukuba. The venue was a recognition of the premier accelerator physics and technology status achieved by this diligent nation

  8. Accelerator shielding benchmark problems

    International Nuclear Information System (INIS)

    Hirayama, H.; Ban, S.; Nakamura, T.

    1993-01-01

    Accelerator shielding benchmark problems prepared by Working Group of Accelerator Shielding in the Research Committee on Radiation Behavior in the Atomic Energy Society of Japan were compiled by Radiation Safety Control Center of National Laboratory for High Energy Physics. Twenty-five accelerator shielding benchmark problems are presented for evaluating the calculational algorithm, the accuracy of computer codes and the nuclear data used in codes. (author)

  9. Wake field accelerators

    International Nuclear Information System (INIS)

    Wilson, P.B.

    1986-02-01

    In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered

  10. CONFERENCE: Computers and accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1984-01-15

    In September of last year a Conference on 'Computers in Accelerator Design and Operation' was held in West Berlin attracting some 160 specialists including many from outside Europe. It was a Europhysics Conference, organized by the Hahn-Meitner Institute with Roman Zelazny as Conference Chairman, postponed from an earlier intended venue in Warsaw. The aim was to bring together specialists in the fields of accelerator design, computer control and accelerator operation.

  11. Japan Accelerator Conference

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-11-15

    At the international level, the high energy accelerator scene evolves rapidly and the International Conference on High Energy Accelerators is where its strong pulse can best be felt. This year, the Conference was held for the first time in Japan, with the 14th meeting in the series having been hosted in August by the Japanese KEK National Laboratory for High Energy Physics, Tsukuba. The venue was a recognition of the premier accelerator physics and technology status achieved by this diligent nation.

  12. CERN Accelerator School

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    The CERN Accelerator School (CAS) recently held its Advanced Accelerator Physics course in Greece on the island of Rhodes. Complementing the general course in Finland last year, this course was organized together with the University of Athens and NCSR. Demokritos. Accelerator specialists from Europe, CIS, Japan and USA followed two weeks of ''state-of-theart'' lectures designed to complete their education in the field

  13. Applying the accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Barbalat, Oscar

    1989-12-15

    Originally developed as tools for frontier physics, particle accelerators provide valuable spinoff benefits in applied research and technology. These accelerator applications are the subject of a biennial meeting in Denton, Texas, but the increasing activity in this field resulted this year (5-9 September) in the first European Conference on Accelerators in Applied Research and Technology, organized by K. Bethge of Frankfurt's Goethe University. The meeting reflected a wide range of applications - ion beam analysis, exploitation of nuclear microbeams, accelerator mass spectrometry, applications of photonuclear reactions, ion beam processing, synchrotron radiation for semiconductor technology, specialized technology.

  14. Laser-driven accelerators

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Several devices for using laser fields have been proposed and they can be classified in three broad categories - 'far-field' accelerators (such as the principle of inverse free electron lasers), 'media' accelerators (which, for example, use the inverse Cherenkov effect or laser-controlled plasma waves), and 'near-field' accelerators (using a loaded guiding structure such as cavities or gratings). These different approaches come from the fact that a particle cannot be accelerated by the absorption of single photons (because of momentum conservation) and thus some other element has to intervene. (orig./HSI).

  15. Illinois Accelerator Research Center

    Science.gov (United States)

    Kroc, Thomas K.; Cooper, Charlie A.

    The Illinois Accelerator Research Center (IARC) hosts a new accelerator development program at Fermi National Accelerator Laboratory. IARC provides access to Fermi's state-of-the-art facilities and technologies for research, development and industrialization of particle accelerator technology. In addition to facilitating access to available existing Fermi infrastructure, the IARC Campus has a dedicated 36,000 ft2 Heavy Assembly Building (HAB) with all the infrastructure needed to develop, commission and operate new accelerators. Connected to the HAB is a 47,000 ft2 Office, Technology and Engineering (OTE) building, paid for by the state, that has office, meeting, and light technical space. The OTE building, which contains the Accelerator Physics Center, and nearby Accelerator and Technical divisions provide IARC collaborators with unique access to world class expertise in a wide array of accelerator technologies. At IARC scientists and engineers from Fermilab and academia work side by side with industrial partners to develop breakthroughs in accelerator science and translate them into applications for the nation's health, wealth and security.

  16. High Gradient Accelerator Research

    International Nuclear Information System (INIS)

    Temkin, Richard

    2016-01-01

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  17. Interacting with accelerators

    International Nuclear Information System (INIS)

    Dasgupta, S.

    1994-01-01

    Accelerators are research machines which produce energetic particle beam for use as projectiles to effect nuclear reactions. These machines along with their services and facilities may occupy very large areas. The man-machine interface of accelerators has evolved with technological changes in the computer industry and may be partitioned into three phases. The present paper traces the evolution of man-machine interface from the earliest accelerators to the present computerized systems incorporated in modern accelerators. It also discusses the advantages of incorporating expert system technology for assisting operators. (author). 8 ref

  18. Accelerator-based BNCT.

    Science.gov (United States)

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. © 2013 Elsevier Ltd. All rights reserved.

  19. Applying the accelerator

    International Nuclear Information System (INIS)

    Barbalat, Oscar

    1989-01-01

    Originally developed as tools for frontier physics, particle accelerators provide valuable spinoff benefits in applied research and technology. These accelerator applications are the subject of a biennial meeting in Denton, Texas, but the increasing activity in this field resulted this year (5-9 September) in the first European Conference on Accelerators in Applied Research and Technology, organized by K. Bethge of Frankfurt's Goethe University. The meeting reflected a wide range of applications - ion beam analysis, exploitation of nuclear microbeams, accelerator mass spectrometry, applications of photonuclear reactions, ion beam processing, synchrotron radiation for semiconductor technology, specialized technology

  20. Superconducting linear accelerator cryostat

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Elkonin, B.V.; Sokolowski, J.S.

    1984-01-01

    A large vertical cryostat for a superconducting linear accelerator using quarter wave resonators has been developed. The essential technical details, operational experience and performance are described. (author)

  1. Electron acceleration by turbulent plasmoid reconnection

    Science.gov (United States)

    Zhou, X.; Büchner, J.; Widmer, F.; Muñoz, P. A.

    2018-04-01

    In space and astrophysical plasmas, like in planetary magnetospheres, as that of Mercury, energetic electrons are often found near current sheets, which hint at electron acceleration by magnetic reconnection. Unfortunately, electron acceleration by reconnection is not well understood yet, in particular, acceleration by turbulent plasmoid reconnection. We have investigated electron acceleration by turbulent plasmoid reconnection, described by MHD simulations, via test particle calculations. In order to avoid resolving all relevant turbulence scales down to the dissipation scales, a mean-field turbulence model is used to describe the turbulence of sub-grid scales and their effects via a turbulent electromotive force (EMF). The mean-field model describes the turbulent EMF as a function of the mean values of current density, vorticity, magnetic field as well as of the energy, cross-helicity, and residual helicity of the turbulence. We found that, mainly around X-points of turbulent reconnection, strongly enhanced localized EMFs most efficiently accelerated electrons and caused the formation of power-law spectra. Magnetic-field-aligned EMFs, caused by the turbulence, dominate the electron acceleration process. Scaling the acceleration processes to parameters of the Hermean magnetotail, electron energies up to 60 keV can be reached by turbulent plasmoid reconnection through the thermal plasma.

  2. New particle accelerations by magnetized plasma shock waves

    International Nuclear Information System (INIS)

    Takeuchi, Satoshi

    2005-01-01

    Three mechanisms concerning particle accelerations are proposed to account for the high energy of cosmic rays. A model of magnetized plasma clouds is used to simulate a shock-type wave. The attainable energies of test particles colliding with the moving magnetic clouds are investigated by analytical and numerical methods for the three mechanisms. The magnetic trapping acceleration is a new type of particle trapping and acceleration in which, in principle, the test particle is accelerated indefinitely; hence, this mechanism surpasses the Fermi-type acceleration. In the single-step acceleration, the test particle obtains a significant energy gain even though it only experiences a single collision. Lastly, there is the bouncing acceleration by which the test particle is substantially accelerated due to repeated collisions

  3. Accelerator Modeling with MATLAB Accelerator Toolbox

    International Nuclear Information System (INIS)

    2002-01-01

    This paper introduces Accelerator Toolbox (AT)--a collection of tools to model storage rings and beam transport lines in the MATLAB environment. The objective is to illustrate the flexibility and efficiency of the AT-MATLAB framework. The paper discusses three examples of problems that are analyzed frequently in connection with ring-based synchrotron light sources

  4. Accelerator research studies. Progress report

    International Nuclear Information System (INIS)

    1984-06-01

    Progress is reported in both experimental studies as well as theoretical understanding of the beam transport problem. Major highlights are: (a) the completion of the first channel section with 12 periods and two matching solenoids, (b) measurements of beam transmission and emittance in this 12-lens channel, (c) extensive analytical and numerical studies of the beam transport problem in collaboration with GSI (W. Germany), (d) detailed measurements and calculations of beam propagation through one lens with spherical aberration and space charge, and (e) completion of the emittance grids at the Rutherford-Appleton Laboratory. Our main objectives in Task B of our research program are: (a) study of collective acceleration of positive ions from a localized plasma source by an intense relativistic electron beam (IREB), (b) external control of the IREB beam front by a slow-wave structure to achieve higher ion energies - the Beam Front Accelerator (BFA) concept, (c) study of ion and electron acceleration and other applications of a plasma focus device, and (d) theoretical studies in support of (a) and (b). Our research in these areas has been oriented towards obtaining an improved understanding of the physical processes at work in these experiments and, subsequently, achieving improved performance for specific potential applications

  5. New localities of Orobanche bartlingii Griseb. in the Silesian-Cracow Upland as a result of the spread of Libanotis pyrenaica (L. Bourg. due to the changes in land use

    Directory of Open Access Journals (Sweden)

    Babczyńska-Sendek Beata

    2015-09-01

    Full Text Available Human activity is a factor strongly influencing the current state of vegetation. The abandonment of traditional land use enables uncontrolled secondary succession. Libanotis pyrenaica, a host plant for Orobanche bartlingii, is a great example of species that spread as a result of this process, especially in the area of the Silesian-Cracow Upland. The aim of this study is to show that the expansion of L. pyrenaica caused by changes in land use promotes spreading of O. bartlingii - a species rare in Poland and Europe. During the field research conducted in the last decade, further localities of O. bartlingii were found. The gathered data were summarized to supplement the known distribution of the species and to present floristic and ecological characteristics of the phytocenoses with the participation of L. pyrenaica and O. bartlingii.

  6. Santa Fe Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    The 10th USA National Particle Accelerator Conference was hosted this year by the Los Alamos National Laboratory in Santa Fe from 21-23 March. It was a resounding success in emphasizing the ferment of activity in the accelerator field. About 900 people registered and about 500 papers were presented in invited and contributed talks and poster sessions

  7. Relativistic Shock Acceleration

    International Nuclear Information System (INIS)

    Duffy, P.; Downes, T.P.; Gallant, Y.A.; Kirk, J.G.

    1999-01-01

    In this paper we briefly review the basic theory of shock waves in relativistic hydrodynamics and magneto-hydrodynamics, emphasising some astrophysically interesting cases. We then present an overview of the theory of particle acceleration at such shocks describing the methods used to calculate the spectral indices of energetic particles. Recent results on acceleration at ultra-relativistic shocks are discussed. (author)

  8. CERN Accelerator School

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-01-15

    The CERN Accelerator School (CAS) offers a regular course on general accelerator physics. The first basic course was given in September 1984 at Orsay, France, and last September the advanced course was jointly organized by CAS, Oxford's Nuclear Physics Laboratory and the Rutherford Appleton Laboratory, and held at The Queen's College, Oxford.

  9. Accelerator for nuclear transmutation

    International Nuclear Information System (INIS)

    Schapira, J.P.

    1984-01-01

    A review on nuclear transmutation of radioactive wastes using particle accelerators is given. Technical feasibility, nuclear data, costs of various projects are discussed. It appears that one high energy accelerator (1500 MeV, 300 mA proton) could probably handle the amount of actinides generated by the actual French nuclear program [fr

  10. Diagnostics for induction accelerators

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960's to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore's Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail

  11. Diagnostics for induction accelerators

    International Nuclear Information System (INIS)

    Fessenden, T.J.

    1997-01-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at Lawrence Livermore National Laboratory (LLNL) from the early 1960s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400-ns pulses. The Advanced Test Accelerator (ATA) built at Livermore close-quote s Site 300 produced 10,000-Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and Lawrence Berkeley National Laboratory (LBNL). This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high-current, short-pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail. copyright 1997 American Institute of Physics

  12. Hamburg Accelerator Conference (2)

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Edmund J.N. [CERN Accelerator School (Switzerland)

    1992-11-15

    From 20-24 July, Hamburg welcomed the Fifteenth International Conference on High Energy Accelerators (HEACC). The HEACC Conference traditionally reviews the status of all major accelerator projects whether they are already running like clockwork, still in the construction phase, or waiting impatiently for financial approval.

  13. Charged particle accelerator

    International Nuclear Information System (INIS)

    Arakawa, Kazuo.

    1969-01-01

    An accelerator is disclosed having a device which permits the electrodes of an accelerator tube to be readily conditioned in an uncomplicated manner before commencing operation. In particle accelerators, it is necessary to condition the accelerator electrodes before a stable high voltage can be applied. Large current accelerators of the cockcroft-walton type require a complicated manual operation which entails applying to the electrodes a low voltage which is gradually increased to induce a vacuum discharge and then terminated. When the discharge attains an extremely low level, the voltage is again impressed and again raised to a high value in low current type accelerators, a high voltage power supply charges the electrodes once to induce discharge followed by reapplying the voltage when the vacuum discharge reaches a low level, according to which high voltage is automatically applied. This procedure, however, requires that the high voltage power supply be provided with a large internal resistance to limit the current to within several milliamps. The present invention connects a high voltage power supply and an accelerator tube through a discharge current limiting resistor wired in parallel with a switch. Initially, the switch is opened enabling the power supply to impress a voltage limited to a prescribed value by a suitably chosen resistor. Conditioning is effected by allowing the voltage between electrodes to increase and is followed by closing the switch through which high voltage is applied directly to the accelerator for operation. (K.J. Owens)

  14. Asia honours accelerator physicists

    CERN Multimedia

    2010-01-01

    "Steve Meyers of Cern and Jie Wei of Beijing's Tsinghua University are the first recipients of a new prize for particle physics. The pair were honoured for their contributions to numerous particle-accelerator projects - including Cern's Large Hadron Collider - by the Asian Committee for Future Accelerators (ACFA)..." (1 paragraph)

  15. Accelerators Beyond The Tevatron?

    Energy Technology Data Exchange (ETDEWEB)

    Lach, Joseph; /Fermilab

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  16. CERN Accelerator School

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The CERN Accelerator School (CAS) offers a regular course on general accelerator physics. The first basic course was given in September 1984 at Orsay, France, and last September the advanced course was jointly organized by CAS, Oxford's Nuclear Physics Laboratory and the Rutherford Appleton Laboratory, and held at The Queen's College, Oxford

  17. Thoughts on accelerator tubes

    International Nuclear Information System (INIS)

    Larson, J.D.

    1978-01-01

    A brief, subjective review is given of mechanisms that may be limiting electrostatic accelerator tubes to present levels of performance. Suggestions are made for attacking these limitations with the purpose of stimulating the thinking of designers and users of electrostatic accelerators

  18. KEK digital accelerator

    Directory of Open Access Journals (Sweden)

    T. Iwashita

    2011-07-01

    Full Text Available The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

  19. Thoughts of accelerator tubes

    International Nuclear Information System (INIS)

    Larson, J.D.

    1977-01-01

    A brief, subjective review is given of mechanisms that may be limiting electrostatic accelerator tubes to present levels of performance. Suggestions are made for attacking these limitations with the purpose of stimulating the thinking of designers and users of electrostatic accelerators

  20. Racetrack linear accelerators

    International Nuclear Information System (INIS)

    Rowe, C.H.; Wilton, M.S. de.

    1979-01-01

    An improved recirculating electron beam linear accelerator of the racetrack type is described. The system comprises a beam path of four straight legs with four Pretzel bending magnets at the end of each leg to direct the beam into the next leg of the beam path. At least one of the beam path legs includes a linear accelerator. (UK)

  1. Linear Accelerator (LINAC)

    Science.gov (United States)

    ... uses microwave technology (similar to that used for radar) to accelerate electrons in a part of the accelerator called the "wave guide," then allows ... risk of accidental exposure is extremely low. top of page This page was ... No Please type your comment or suggestion into the following text ...

  2. Hamburg Accelerator Conference (2)

    International Nuclear Information System (INIS)

    Wilson, Edmund J.N.

    1992-01-01

    From 20-24 July, Hamburg welcomed the Fifteenth International Conference on High Energy Accelerators (HEACC). The HEACC Conference traditionally reviews the status of all major accelerator projects whether they are already running like clockwork, still in the construction phase, or waiting impatiently for financial approval

  3. Accelerator breeder concept

    International Nuclear Information System (INIS)

    Bartholomew, G.A.; Fraser, J.S.; Garvey, P.M.

    1978-10-01

    The principal components and functions of an accelerator breeder are described. The role of the accelerator breeder as a possible long-term fissile production support facility for CANDU (Canada Deuterium Uranium) thorium advanced fuel cycles and the Canadian research and development program leading to such a facility are outlined. (author)

  4. Semiconductor acceleration sensor

    Science.gov (United States)

    Ueyanagi, Katsumichi; Kobayashi, Mitsuo; Goto, Tomoaki

    1996-09-01

    This paper reports a practical semiconductor acceleration sensor especially suited for automotive air bag systems. The acceleration sensor includes four beams arranged in a swastika structure. Two piezoresistors are formed on each beam. These eight piezoresistors constitute a Wheatstone bridge. The swastika structure of the sensing elements, an upper glass plate and a lower glass plate exhibit the squeeze film effect which enhances air dumping, by which the constituent silicon is prevented from breakdown. The present acceleration sensor has the following features. The acceleration force component perpendicular to the sensing direction can be cancelled. The cross-axis sensitivity is less than 3 percent. And, the erroneous offset caused by the differences between the thermal expansion coefficients of the constituent materials can be canceled. The high aspect ratio configuration realized by plasma etching facilitates reducing the dimensions and improving the sensitivity of the acceleration sensor. The present acceleration sensor is 3.9 mm by 3.9 mm in area and 1.2 mm in thickness. The present acceleration sensor can measure from -50 to +50 G with sensitivity of 0.275 mV/G and with non-linearity of less than 1 percent. The acceleration sensor withstands shock of 3000 G.

  5. Molecular ion acceleration using tandem accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Yuichi; Mizuhashi, Kiyoshi; Tajima, Satoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1996-12-01

    In TIARA compound beam radiation system, cluster beams have been produced using 3 MV tandem accelerator (9SDH-2) to supply them to various radiation on injection experiments. Till now, productions of C{sub 2-8}, Si{sub 2-4} and O{sub 2} and their accelerations up to 6 MeV have been succeeded. This study aimed at production and acceleration of B{sub 2-4} and LiF. Anion clusters were produced using the conventional ion source of cesium sputter type. The proportions of atoms, molecules and clusters elicited from the ion source were varied depending on the material`s properties and the operating conditions of ion source such as sample temperature, sputter voltage and the shape of sample. The anion clusters were accelerated toward the high voltage terminal in the center of tandem accelerator, leading to cations through losing their electrons by the collision to N{sub 2} gas in a charge conversion cell at the terminal. Positively charged cluster ions could be obtained by modulating the pressure of N{sub 2} gas. Thus, B{sub 2} (64 nA), B{sub 3} (4.4 nA) and B{sub 4} (2.7 nA) have been produced and their maximum survival probabilities were higher than those of carbon or silicon clusters. In addition, the relationship between beam current and gas pressure was investigated for Bn (n = 2-4) and LiF. (M.N.)

  6. Plasma based accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, Allen [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    2015-05-01

    The concept of laser-induced plasma wakefields as a technique to accelerate charged particles was introduced 35 years ago as a means to go beyond the accelerating gradients possible with metallic cavities supporting radio frequency electromagnetic fields. Significant developments in laser technology have made possible the pulse intensity needed to realize this concept, and rapid progress is now underway in the realization of laser-driven plasma wakefield acceleration. It has also been realized that similar accelerating gradients can be produced by particle beams propagating in plasmas, and experimental programs have also been undertaken to study this possibility. Positive results have been achieved with electron-driven plasma wakefields, and a demonstration experiment with proton-driven wakefields is under construction at CERN. The concepts behind these different schemes and their pros and cons are described, as well as the experimental results achieved. An outlook for future practical uses of plasma based accelerators will also be given.

  7. TIARA electrostatic accelerator facility

    International Nuclear Information System (INIS)

    Tajima, Satoshi; Takada, Isao; Mizuhashi, Kiyoshi; Uno, Sadanori; Ohkoshi, Kiyonori; Nakajima, Yoshinori; Saitoh, Yuichi; Ishii, Yasuyuki; Kamiya, Tomihiro

    1996-07-01

    In order to promote the Advanced Radiation Technology Project, Japan Atomic Energy Research Institute constructed TIARA facility composed of four ion accelerators at Takasaki Radiation Chemistry Research Establishment for the period from 1988 to 1993. A 3MV tandem accelerator and an AVF cycrotron were completed in 1991 as the first phase of the construction, and a 3MV single-ended accelerator and a 400kV ion implanter were completed in 1993 as the second phase. Three electrostatic accelerators, the tandem, the single-ended and the implanter, were installed in the Multiple-beam facility of TIARA and have been operated for various experiments with using single, dual and triple beams without any serious trouble. This report describes the constructive works, machine performances, control systems, safety systems and accessory equipments of the electrostatic accelerators. (author)

  8. 2016 Accelerators meeting

    International Nuclear Information System (INIS)

    Spiro, Michel; Revol, Jean-Luc; Biarrotte, Jean-Luc; Napoly, Olivier; Jardin, Pascal; Chautard, Frederic; Thomas, Jean Charles; Petit, Eric

    2016-09-01

    The Accelerators meeting is organised every two years by the Accelerators division of the French Society of Physics (SFP). It brings together about 50 participants during a one-day meeting. The morning sessions are devoted to scientific presentations while the afternoon is dedicated to technical visits of facilities. This document brings together the available presentations (slides): 1 - Presentation of the Ganil - Grand accelerateur national d'ions lourds/Big national heavy-ion accelerator, Caen (Jardin, Pascal); 2 - Presentation of the Accelerators division of the French Society of Physics (Revol, Jean-Luc); 3 - Forward-looking and Prospective view (Napoly, Olivier); 4 - Accelerators at the National Institute of Nuclear and particle physics, situation, Forward-looking and Prospective view (Biarrotte, Jean-Luc); 5 - GANIL-SPIRAL2, missions and goals (Thomas, Jean Charles); 6 - The SPIRAL2 project (Petit, Eric)

  9. Collinear wake field acceleration

    International Nuclear Information System (INIS)

    Bane, K.L.F.; Chen, P.; Wilson, P.B.

    1985-04-01

    In the Voss-Weiland scheme of wake field acceleration a high current, ring-shaped driving bunch is used to accelerate a low current beam following along on axis. In such a structure, the transformer ratio, i.e., the ratio of maximum voltage that can be gained by the on-axis beam and the voltage lost by the driving beam, can be large. In contrast, it has been observed that for an arrangement in which driving and driven bunches follow the same path, and where the current distribution of both bunches is gaussian, the transformer ratio is not normally greater than two. This paper explores some of the possibilities and limitations of a collinear acceleration scheme. In addition to its application to wake field acceleration in structures, this study is also of interest for the understanding of the plasma wake field accelerator. 11 refs., 4 figs

  10. Standing wave accelerating structures

    International Nuclear Information System (INIS)

    Zavadtsev, A.A.; Zverev, B.V.; Sobepin, N.P.

    1984-01-01

    Accelerating ELA structures are considered and chosen for applied purposes of special designation. Accelerating structures with the standing wave are considered most effective for small size ELA. Designs and results of experimental investigation of two new accelerating structures are described. These are structures of the ''ring'' type with a decreased number of excitinq oscillation types and strucuture with transverse rods with a twice smaller transverse size as compared with the biperiodical structure with internal connection resonators. The accelerating biperiodical structures of the conventional type by the fact that the whole structure is not a linear chain of connected resonators, but a ring one. Model tests have shown that the homogeneous structure with transverse rods (STR) at the frequency of 2.8 GHz in the regime of the standing wave has an effective shunt resistance equalling 23 MOhm/m. It is shown that the small transverse size of biperiodic STR makes its application in logging linear electron accelerators

  11. Communication system for the Tristan accelerators

    International Nuclear Information System (INIS)

    Katoh, T.; Takeda, S.; Kudo, K.; Akiyama, A.

    1987-01-01

    Communication system used for operation of the TRISTAN accelerators consists of a ring network for control computer system, a video information network, and a broadband video/digital data network. In this paper the video information network using optical fiber cables and the broadband CATV and Local Area network are described

  12. Intrinsic spatial resolution limitations due to differences between positron emission position and annihilation detection localization; Limitacoes da resolucao espacial intrinseca devido as diferencas entre a posicao da emissao do positron e a deteccao da localizacao de aniquilacao

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Pedro; Malano, Francisco; Valente, Mauro, E-mail: valente@famaf.unc.edu.ar [Universidad Nacional de Cordoba, Cordoba (Argentina). Fac. de Matematica, Astronomia y Fisica (FaMAF)

    2012-07-01

    Since its successful implementation for clinical diagnostic, positron emission tomography (PET) represents the most promising medical imaging technique. The recent major growth of PET imaging is mainly due to its ability to trace the biologic pathways of different compounds in the patient's body, assuming the patient can be labeled with some PET isotope. Regardless of the type of isotope, the PET imaging method is based on the detection of two 511-keV gamma photons being emitted in opposite directions, with almost 180 deg between them, as a consequence of electron-positron annihilation. Therefore, this imaging method is intrinsically limited by random uncertainties in spatial resolutions, related with differences between the actual position of positron emission and the location of the detected annihilation. This study presents an approach with the Monte Carlo method to analyze the influence of this effect on different isotopes of potential implementation in PET. (author)

  13. Diagnostics for advanced laser acceleration experiments

    International Nuclear Information System (INIS)

    Misuri, Alessio

    2002-01-01

    The first proposal for plasma based accelerators was suggested by 1979 by Tajima and Dawson. Since then there has been a tremendous progress both theoretically and experimentally. The theoretical progress is particularly due to the growing interest in the subject and to the development of more accurate numerical codes for the plasma simulations (especially particle-in-cell codes). The experimental progress follows from the development of multi-terawatt laser systems based on the chirped-pulse amplification technique. These efforts have produced results in several experiments world-wide, with the detection of accelerated electrons of tens of MeV. The peculiarity of these advanced accelerators is their ability to sustain extremely large acceleration gradients. In the conventional radio frequency linear accelerators (RF linacs) the acceleration gradients are limited roughly to 100 MV/m; this is partially due to breakdown which occurs on the walls of the structure. The electrical breakdown is originated by the emission of the electrons from the walls of the cavity. The electrons cause an avalanche breakdown when they reach other metal parts of the RF linacs structure

  14. Diagnostics for advanced laser acceleration experiments

    Energy Technology Data Exchange (ETDEWEB)

    Misuri, Alessio [Univ. of Pisa (Italy)

    2002-01-01

    The first proposal for plasma based accelerators was suggested by 1979 by Tajima and Dawson. Since then there has been a tremendous progress both theoretically and experimentally. The theoretical progress is particularly due to the growing interest in the subject and to the development of more accurate numerical codes for the plasma simulations (especially particle-in-cell codes). The experimental progress follows from the development of multi-terawatt laser systems based on the chirped-pulse amplification technique. These efforts have produced results in several experiments world-wide, with the detection of accelerated electrons of tens of MeV. The peculiarity of these advanced accelerators is their ability to sustain extremely large acceleration gradients. In the conventional radio frequency linear accelerators (RF linacs) the acceleration gradients are limited roughly to 100 MV/m; this is partially due to breakdown which occurs on the walls of the structure. The electrical breakdown is originated by the emission of the electrons from the walls of the cavity. The electrons cause an avalanche breakdown when they reach other metal parts of the RF linacs structure.

  15. Analyzing radial acceleration with a smartphone acceleration sensor

    Science.gov (United States)

    Vogt, Patrik; Kuhn, Jochen

    2013-03-01

    This paper continues the sequence of experiments using the acceleration sensor of smartphones (for description of the function and the use of the acceleration sensor, see Ref. 1) within this column, in this case for analyzing the radial acceleration.

  16. Centrifugal acceleration in the magnetotail lobes

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2010-02-01

    Full Text Available Combined Cluster EFW and EDI measurements have shown that cold ion outflow in the magnetospheric lobes dominates the hydrogen ion outflow from the Earth's atmosphere. The ions have too low kinetic energy to be measurable with particle instruments, at least for the typical spacecraft potential of a sunlit spacecraft in the tenuous lobe plasmas outside a few RE. The measurement technique yields both density and bulk velocity, which can be combined with magnetic field measurements to estimate the centrifugal acceleration experienced by these particles. We present a quantitative estimate of the centrifugal acceleration, and the velocity change with distance which we would expect due to centrifugal acceleration. It is found that the centrifugal acceleration is on average outward with an average value of about of 5 m s−2. This is small, but acting during long transport times and over long distances the cumulative effect is significant, while still consistent with the relatively low velocities estimated using the combination of EFW and EDI data. The centrifugal acceleration should accelerate any oxygen ions in the lobes to energies observable by particle spectrometers. The data set also put constraints on the effectiveness of any other acceleration mechanisms acting in the lobes, where the total velocity increase between 5 and 19 RE geocentric distance is less than 5 km s−1.

  17. Multicavity proton cyclotron accelerator

    Directory of Open Access Journals (Sweden)

    J. L. Hirshfield

    2002-08-01

    Full Text Available A mechanism for acceleration of protons is described, in which energy gain occurs near cyclotron resonance as protons drift through a sequence of rotating-mode TE_{111} cylindrical cavities in a strong nearly uniform axial magnetic field. Cavity resonance frequencies decrease in sequence from one another with a fixed frequency interval Δf between cavities, so that synchronism can be maintained between the rf fields and proton bunches injected at intervals of 1/Δf. An example is presented in which a 122 mA, 1 MeV proton beam is accelerated to 961 MeV using a cascade of eight cavities in an 8.1 T magnetic field, with the first cavity resonant at 120 MHz and with Δf=8 MHz. Average acceleration gradient exceeds 40 MV/m, average effective shunt impedance is 223 MΩ/m, but maximum surface field in the cavities does not exceed 7.2 MV/m. These features occur because protons make many orbital turns in each cavity and thus experience acceleration from each cavity field many times. Longitudinal and transverse stability appear to be intrinsic properties of the acceleration mechanism, and an example to illustrate this is presented. This acceleration concept could be developed into a proton accelerator for a high-power neutron spallation source, such as that required for transmutation of nuclear waste or driving a subcritical fission burner, provided a number of significant practical issues can be addressed.

  18. The miniature accelerator

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    The image that most people have of CERN is of its enormous accelerators and their capacity to accelerate particles to extremely high energies. But thanks to some cutting-edge studies on beam dynamics and radiofrequency technology, along with innovative construction techniques, teams at CERN have now created the first module of a brand-new accelerator, which will be just 2 metres long. The potential uses of this miniature accelerator will include deployment in hospitals for the production of medical isotopes and the treatment of cancer. It’s a real David-and-Goliath story.   Serge Mathot, in charge of the construction of the "mini-RFQ", pictured with the first of the four modules that will make up the miniature accelerator. The miniature accelerator consists of a radiofrequency quadrupole (RFQ), a component found at the start of all proton accelerator chains around the world, from the smallest to the largest. The LHC is designed to produce very high-intensity beams ...

  19. Superconductivity and future accelerators

    International Nuclear Information System (INIS)

    Danby, G.T.; Jackson, J.W.

    1963-01-01

    For 50 years particle accelerators employing accelerating cavities and deflecting magnets have been developed at a prodigious rate. New accelerator concepts and hardware ensembles have yielded great improvements in performance and GeV/$. The great idea for collective acceleration resulting from intense auxiliary charged-particle beams or laser light may or may not be just around the corner. In its absence, superconductivity (SC) applied both to rf cavities and to magnets opened up the potential for very large accelerators without excessive energy consumption and with other economies, even with the cw operation desirable for colliding beams. HEP has aggressively pioneered this new technology: the Fermilab single ring 1 TeV accelerator - 2 TeV collider is near the testing stage. Brookhaven National Laboratory's high luminosity pp 2 ring 800 GeV CBA collider is well into construction. Other types of superconducting projects are in the planning stage with much background R and D accomplished. The next generation of hadron colliders under discussion involves perhaps a 20 TeV ring (or rings) with 40 TeV CM energy. This is a very large machine: even if the highest practical field B approx. 10T is used, the radius is 10x that of the Fermilab accelerator. An extreme effort to get maximum GeV/$ may be crucial even for serious consideration of funding

  20. Accelerator programme at CAT

    International Nuclear Information System (INIS)

    Ramamurthi, S.S.

    1991-01-01

    The Accelerator Programme at the Centre for Advanced Technology (CAT), Indore, has very broad based concept under which all types of accelerators are to be taken up for design and fabrication. This centre will be housing a wide variety of accelerators to serve as a common facility for the universities, national laboratories in addition to laboratories under the Department of Atomic Energy. In the first phase of the programme, a series of electron accelerators are designed and fabricated. They are synchrotron radiation sources of 450 MeV (INDUS-I) and of 2 GeV (INDUS-II), microtron upto energy of 20 MeV, linear accelerator upto 20 MeV, and DC Accelerator for industrial irradiation upto 750 KeV and 20 KW. A proton accelerator of 300 MeV with 20 MeV linac injector is also designed. CAT is also developing a strong base for support technologies like ultra high vacuum, radio frequency and microwaves, DC pulsed and superconducting magnets, power supplies and controls etc. These technologies are very useful for other industrial applications also. To develop user groups to utilise INDUS-II synchrotron radiation source, a batch production of rotating Anode X-ray generators with power supplies has been initiated. So also, the sputter ion pumps, electron guns, turbo molecular pumps are brought into batch production. (author)

  1. Computer programs in accelerator physics

    International Nuclear Information System (INIS)

    Keil, E.

    1984-01-01

    Three areas of accelerator physics are discussed in which computer programs have been applied with much success: i) single-particle beam dynamics in circular machines, i.e. the design and matching of machine lattices; ii) computations of electromagnetic fields in RF cavities and similar objects, useful for the design of RF cavities and for the calculation of wake fields; iii) simulation of betatron and synchrotron oscillations in a machine with non-linear elements, e.g. sextupoles, and of bunch lengthening due to longitudinal wake fields. (orig.)

  2. Accelerated Hypertension after Venlafaxine Usage

    Directory of Open Access Journals (Sweden)

    Yüksel Kıvrak

    2014-01-01

    Full Text Available Venlafaxine is the first antidepressant that acts via inhibiting serotonin and noradrenaline reuptake. Hypertension is observed in doses exceeding 300 mg/day and is the most feared complication. We report a patient with accelerated hypertension after venlafaxine use observed at a dose of 150 mg/day. A 23-year-old patient with symptoms of insomnia, depression, anhedonia, fatigue admitted our clinic. Venlafaxine at a dose of 75 mg/day was initiated after he was diagnosed with major depressive disorder. After 5 months, venlafaxine dose was uptitrated to 150 mg/day due to inadequate response to drug. After using venlafaxine for ten months at the dose of 150 mg/day, he admitted our clinic with headache and epistaxis. He was hospitalized after his blood pressure was measured as 210/170 mmHg. No secondary causes for hypertension were found, and venlafaxine treatment was considered possible etiologic factor. After stopping venlafaxine treatment, his blood pressure was reverted back to normal limits. While mild elevation of blood pressure could be observed after venlafaxine treatment, this case shows that accelerated hypertension with a diastolic blood pressure rise above 120 mmHg could be observed at relatively low doses of venlafaxine. Close monitoring of blood pressure is necessary after initiation of treatment, as accelerated hypertension could cause endorgan damage with potentially catastrophic results.

  3. High Power Electron Accelerator Prototype

    CERN Document Server

    Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

    2005-01-01

    In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

  4. Injection and extraction techniques in circular accelerators

    International Nuclear Information System (INIS)

    Tang Jingyu

    2008-01-01

    Injection and extraction are usually the key systems in circular accelerators. They play important roles in transferring the beam from one stage acceleration to the other or to experimental stations. It is also in the injection and extraction regions where beam losses happen mostly. Due to the tight space and to reduce the perturbation to the circulating orbit, the devices are usually designed to meet special requirements such as compactness, small stray field, fast rise time or fall time, etc. Usual injection and extraction devices include septum magnets, kicker magnets, electrostatic deflectors, slow bump magnets and strippers. In spite of different accelerators and specification for the injection and extraction devices, many techniques are shared in the design and manufacturing. This paper gives a general review on the techniques employed in the major circular accelerators in China. (authors)

  5. Machine Protection: Availability for Particle Accelerators

    CERN Document Server

    Apollonio, Andrea; Schmidt, Ruediger

    2015-03-16

    Machine availability is a key indicator for the performance of the next generation of particle accelerators. Availability requirements need to be carefully considered during the design phase to achieve challenging objectives in different fields, as e.g. particle physics and material science. For existing and future High-Power facilities, such as ESS (European Spallation Source) and HL-LHC (High-Luminosity LHC), operation with unprecedented beam power requires highly dependable Machine Protection Systems (MPS) to avoid any damage-induced downtime. Due to the high complexity of accelerator systems, finding the optimal balance between equipment safety and accelerator availability is challenging. The MPS architecture, as well as the choice of electronic components, have a large influence on the achievable level of availability. In this thesis novel methods to address the availability of accelerators and their protection systems are presented. Examples of studies related to dependable MPS architectures are given i...

  6. Memory-Centric Accelerator Design for Convolutional Neural Networks

    NARCIS (Netherlands)

    Peemen, M.C.J.; Setio, A.A.A.; Mesman, B.; Corporaal, H.

    2013-01-01

    In the near future, cameras will be used everywhere as flexible sensors for numerous applications. For mobility and privacy reasons, the required image processing should be local on embedded computer platforms with performance requirements and energy constraints. Dedicated acceleration of

  7. New accelerator ideas

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    In the past, providing higher particle beam energies meant building bigger accelerators. It is now universally accepted that with the current generation of accelerator projects either under construction (such as LEP at CERN) or proposed (such as the Superconducting Super Collider in the US), conventional techniques are reaching their practical limit. With the growing awareness that progress in particle physics requires new methods to accelerate particles, workshops and study groups are being set up across the world to search for ideas for the machines of tomorrow

  8. The auroral electron accelerator

    International Nuclear Information System (INIS)

    Bryant, D.A.; Hall, D.S.

    1989-01-01

    A model of the auroral electron acceleration process is presented in which the electrons are accelerated resonantly by lower-hybrid waves. The essentially stochastic acceleration process is approximated for the purposes of computation by a deterministic model involving an empirically derived energy transfer function. The empirical function, which is consistent with all that is known of electron energization by lower-hybrid waves, allows many, possibly all, observed features of the electron distribution to be reproduced. It is suggested that the process occurs widely in both space and laboratory plasmas. (author)

  9. ACCELERATORS: School report

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-12-15

    The expanded 1987 US Particle Accelerator School, held at Fermilab from 20 July to 14 August, included two two-week sessions. In the first, 101 students covered three university-style courses, listed as upper-division University of Chicago physics, covering the fundamentals of particle beams, magnetic optics and acceleration; relativistic electronics; and high energy storage rings. The 180 participants in the second session profited from 24 short courses presented by experts and covering a wide variety of topics in the physics and technology of particle accelerators.

  10. Hadron accelerators in medicine

    International Nuclear Information System (INIS)

    Amaldi, U.

    1996-01-01

    The application of hadron accelerators (protons and light ions) in cancer therapy is discussed. After a brief introduction on the rationale for the use of heavy charged particles in radiation therapy, a discussion is given on accelerator technology and beam delivery systems. Next, existing and planned facilities are briefly reviewed. The Italian Hadron-therapy Project is then described in some detail, with reference ro both the National Centre for Oncological Hadron-therapy and the design of different types of compact proton accelerators aimed at introducing proton therapy in a large umber of hospitals. (author)

  11. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  12. ACCELERATORS: School prizes

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Dedicated to its goal of encouraging scientists and students to work in the field of particle accelerators, the US Particle Accelerator School (operating since 1981) has switched to a new format. Starting this year, it will offer in alternate years basic accelerator physics plus advanced subjects in both university and symposium styles over four weeks. Expanding the school from two to four weeks gives additional flexibility, and undergraduate participation should be encouraged by university credits being offered for particular courses. In the intervening years, the school will organize six-day topical courses

  13. Accelerator Toolbox for MATLAB

    International Nuclear Information System (INIS)

    Terebilo, Andrei

    2001-01-01

    This paper introduces Accelerator Toolbox (AT)--a collection of tools to model particle accelerators and beam transport lines in the MATLAB environment. At SSRL, it has become the modeling code of choice for the ongoing design and future operation of the SPEAR 3 synchrotron light source. AT was designed to take advantage of power and simplicity of MATLAB--commercially developed environment for technical computing and visualization. Many examples in this paper illustrate the advantages of the AT approach and contrast it with existing accelerator code frameworks

  14. RF linear accelerators

    CERN Document Server

    Wangler, Thomas P

    2008-01-01

    Thomas P. Wangler received his B.S. degree in physics from Michigan State University, and his Ph.D. degree in physics and astronomy from the University of Wisconsin. After postdoctoral appointments at the University of Wisconsin and Brookhaven National Laboratory, he joined the staff of Argonne National Laboratory in 1966, working in the fields of experimental high-energy physics and accelerator physics. He joined the Accelerator Technology Division at Los Alamos National Laboratory in 1979, where he specialized in high-current beam physics and linear accelerator design and technology. In 2007

  15. Auroral electron acceleration

    International Nuclear Information System (INIS)

    Bryant, D.A.

    1989-10-01

    Two theories of auroral electron acceleration are discussed. Part 1 examines the currently widely held view that the acceleration is an ordered process in a quasi-static electric field. It is suggested that, although there are many factors seeming to support this theory, the major qualifications and uncertainties that have been identified combine to cast serious doubt over its validity. Part 2 is devoted to a relatively new interpretation in terms of stochastic acceleration in turbulent electric fields. This second theory, which appears to account readily for most known features of the electron distribution function, is considered to provide a more promising approach to this central question in magnetospheric plasma physics. (author)

  16. New accelerator ideas

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1985-05-15

    In the past, providing higher particle beam energies meant building bigger accelerators. It is now universally accepted that with the current generation of accelerator projects either under construction (such as LEP at CERN) or proposed (such as the Superconducting Super Collider in the US), conventional techniques are reaching their practical limit. With the growing awareness that progress in particle physics requires new methods to accelerate particles, workshops and study groups are being set up across the world to search for ideas for the machines of tomorrow.

  17. Advanced Accelerator Concepts

    Science.gov (United States)

    Siemann, Robert

    1998-04-01

    Current particle accelerators rely on conventional or superconducting radio frequency cavities to accelerate beams of protons or electrons for nuclear and particle research and for medical and materials science studies. New methods for achieving larger accelerating gradients have been proposed and are being studied. These include the use of high power lasers, laser driven plasmas, wake fields generated by intense low energy beams, and millimeter wavelength EM structures. The studies to date, and the prospects for practical applications of these new ideas will be discussed.

  18. Accelerators Spanish steps

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    In September, the CERN Accelerator School (CAS) held its third General Accelerator Physics Course, the venue this time being Salamanca, the oldest university in Spain. Spain, which rejoined CERN in 1982, now has a vigorous and steadily growing high energy physics community making substantial contributions to physics detector development and successfully involving Spanish industry. However the embryonic accelerator community cannot yet generate an equivalent level of activity, and this important channel for introducing new high technology into industry has yet to be fully exploited

  19. Collisionless shock formation and the prompt acceleration of solar flare ions

    Science.gov (United States)

    Cargill, P. J.; Goodrich, C. C.; Vlahos, L.

    1988-01-01

    The formation mechanisms of collisionless shocks in solar flare plasmas are investigated. The priamry flare energy release is assumed to arise in the coronal portion of a flare loop as many small regions or 'hot spots' where the plasma beta locally exceeds unity. One dimensional hybrid numerical simulations show that the expansion of these 'hot spots' in a direction either perpendicular or oblique to the ambient magnetic field gives rise to collisionless shocks in a few Omega(i), where Omega(i) is the local ion cyclotron frequency. For solar parameters, this is less than 1 second. The local shocks are then subsequently able to accelerate particles to 10 MeV in less than 1 second by a combined drift-diffusive process. The formation mechanism may also give rise to energetic ions of 100 keV in the shock vicinity. The presence of these energetic ions is due either to ion heating or ion beam instabilities and they may act as a seed population for further acceleration. The prompt acceleration of ions inferred from the Gamma Ray Spectrometer on the Solar Maximum Mission can thus be explained by this mechanism.

  20. Ambient dose equivalent and personal points due to photoneutrons outside a facility that houses a linear accelerator of 18 MV varian; Equivalente de dosis ambiental y personal debida a fotoneutrones en puntos externos a una instalacion que alberga un acelerador lineal varian de 18 MV

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, S. A.; Barquero, R.; Gomez-Ros, J. M.; Lallena, A. M.; Ponzano, P. E.

    2011-07-01

    The use of linear accelerators (linacs) with energies above 10 MV radiotherapy treatments RT and IMRT, can improve the distribution of the absorbed dose in the treated area, increasing the effectiveness of radiation treatments. However and as shown in the scientific literature, the production of photoneutrons for energies above 10 MeV can contribute to exposure of both patient and occupationally exposed workers and the public in the vicinity of the installation. It is therefore necessary to determine the value of ambient dose equivalent and staff both inside and outside the facilities that house these accelerators, especially for energies of 15 and 18 MV.

  1. Accelerated recovery after cardiac operations.

    Science.gov (United States)

    Kaplan, Mehmet; Kut, Mustafa Sinan; Yurtseven, Nurgul; Cimen, Serdar; Demirtas, Mahmut Murat

    2002-01-01

    The accelerated-recovery approach, involving early extubation, early mobility, decreased duration of intensive care unit stay, and decreased duration of hospitalization has recently become a controversial issue in cardiac surgery. We investigated timing of extubation, length of intensive care unit stay, and duration of hospitalization in 225 consecutive cardiac surgery patients. Of the 225 patients, 139 were male and 86 were female; average age was 49.73 +/- 16.95 years. Coronary artery bypass grafting was performed in 127 patients; 65 patients underwent aortic and/or mitral or pulmonary valvular operations; 5 patients underwent valvular plus coronary artery operations; and in 28 patients surgical interventions for congenital anomalies were carried out. The accelerated-recovery approach could be applied in 169 of the 225 cases (75.11%). Accelerated-recovery patients were extubated after an average of 3.97 +/- 1.59 hours, and the average duration of stay in the intensive care unit was 20.93 +/- 2.44 hours for these patients. Patients were discharged if they met all of the following criteria: hemodynamic stability, cooperativeness, ability to initiate walking exercises within wards, lack of pathology in laboratory investigations, and psychological readiness for discharge. Mean duration of hospitalization for accelerated-recovery patients was 4.24 +/- 0.75 days. Two patients (1.18%) who were extubated within the first 6 hours required reintubation. Four patients (2.36%) who were sent to the wards returned to intensive care unit due to various reasons and 6 (3.55%) of the discharged patients were rehospitalized. Approaches for decreasing duration of intubation, intensive care unit stay and hospitalization may be applied in elective and uncomplicated cardiac surgical interventions with short duration of aortic cross-clamping and cardiopulmonary bypass, without risking patients. Frequencies of reintubation, return to intensive care unit, and rehospitalization are quite

  2. Thermo-mechanical analysis of an acceleration grid for the international thermonuclear experimental reactor-neutral beam injection system

    International Nuclear Information System (INIS)

    Fujiwara, Yukio; Hanada, Masaya; Okumura, Yoshikazu; Suzuki, Satoshi; Watanabe, Kazuhiro

    2001-01-01

    In the engineering design of a negative-ion beam source for a high-power neutral beam injection (NBI) system, one of the most important issues is thermo-mechanical design of acceleration grids for producing several tens of MW ion beams. An acceleration grid for the international thermonuclear experimental reactor-neutral beam injection (ITER-NBI) system will be subjected to the heat loading as high as 1.5 MW. In the present paper, thermo-mechanical characteristics of the acceleration grid for the ITER-NBI system were analyzed. Numerical simulation indicated that maximum aperture-axis displacement of the acceleration grid due to thermal expansion would be about 0.7 mm for the heat loading of 1.5 MW. From the thin lens theory of beam optics, beamlet deflection angle by the aperture-axis displacement was estimated to be about 2 mrad, which is within the requirement of the engineering design of the ITER-NBI system. Numerical simulation also indicated that no melting on the acceleration grid would occur for a heat loading of 1.5 MW, while local plastic deformation would happen. To avoid the plastic deformation, it is necessary to reduce the heat loading onto the acceleration grid to less than 1 MW

  3. Diffusive Shock Acceleration and Turbulent Reconnection

    Science.gov (United States)

    Garrel, Christian; Vlahos, Loukas; Isliker, Heinz; Pisokas, Theophilos

    2018-05-01

    Diffusive Shock Acceleration (DSA) cannot efficiently accelerate particles without the presence of self-consistently generated or pre-existing strong turbulence (δB/B ˜ 1) in the vicinity of the shock. The problem we address in this article is: if large amplitude magnetic disturbances are present upstream and downstream of a shock then Turbulent Reconnection (TR) will set in and will participate not only in the elastic scattering of particles but also in their heating and acceleration. We demonstrate that large amplitude magnetic disturbances and Unstable Current Sheets (UCS), spontaneously formed in the strong turbulence in the vicinity of a shock, can accelerate particles as efficiently as DSA in large scale systems and on long time scales. We start our analysis with "elastic" scatterers upstream and downstream and estimate the energy distribution of particles escaping from the shock, recovering the well known results from the DSA theory. Next we analyze the additional interaction of the particles with active scatterers (magnetic disturbances and UCS) upstream and downstream of the shock. We show that the asymptotic energy distribution of the particles accelerated by DSA/TR has very similar characteristics with the one due to DSA alone, but the synergy of DSA with TR is much more efficient: The acceleration time is an order of magnitude shorter and the maximum energy reached two orders of magnitude higher. We claim that DSA is the dominant acceleration mechanism in a short period before TR is established, and then strong turbulence will dominate the heating and acceleration of the particles. In other words, the shock serves as the mechanism to set up a strongly turbulent environment, in which the acceleration mechanism will ultimately be the synergy of DSA and TR.

  4. An Accelerator Control Middle Layer Using MATLAB

    International Nuclear Information System (INIS)

    Portmann, Gregory J.; Corbett, Jeff; Terebilo, Andrei

    2005-01-01

    Matlab is a matrix manipulation language originally developed to be a convenient language for using the LINPACK and EISPACK libraries. What makes Matlab so appealing for accelerator physics is the combination of a matrix oriented programming language, an active workspace for system variables, powerful graphics capability, built-in math libraries, and platform independence. A number of software toolboxes for accelerators have been written in Matlab--the Accelerator Toolbox (AT) for machine simulations, LOCO for accelerator calibration, Matlab Channel Access Toolbox (MCA) for EPICS connections, and the Middle Layer. This paper will describe the ''middle layer'' software toolbox that resides between the high-level control applications and the low-level accelerator control system. This software was a collaborative effort between ALS (LBNL) and SPEAR3 (SSRL) but easily ports to other machines. Five accelerators presently use this software. The high-level Middle Layer functionality includes energy ramp, configuration control (save/restore), global orbit correction, local photon beam steering, insertion device compensation, beam-based alignment, tune correction, response matrix measurement, and script-based programs for machine physics studies

  5. On acceleration of plasmoids in magnetohydrodynamic simulations of magnetotail reconnection

    International Nuclear Information System (INIS)

    Scholer, M.; Hautz, R.

    1991-01-01

    The formation and acceleration of plasmoids is investigated by two-dimensional magnetohydrodynamic simulations. The initial equilibrium contains a plasma sheet with a northward magnetic field (B z ) component and a tailward pressure gradient. Reconnection is initiated by three different methods: Case A, a constant resistivity is applied everywhere and a tearing mode evolves, case B, a spatially localized resistivity is fixed in the near-Earth region, and case C, the resistivity is allowed to depend on the electrical current density. In case A, the authors obtain the same results as have been presented by Otto et al. (1990): the tearing instability releases the tension of the closed field lines so that the inherent pressure gradient of the two-dimensional system is not balanced anymore. The pressure gradient then sets the plasmoid into motion. Any sling-shot effect of open magnetic field lines is of minor importance. A completely different behavior has been found in cases B and C. In these cases the high-speed flow in the wedge-shaped region tailward of the near-Earth neutral line pushes against the detached plasmoid and drives it tailward. The ideal terms contributing to the acceleration are still only the pressure and the magnetic field term. However, in these cases the pressure is due to the dynamic pressure of the fast outflow from the reconnection region. The outflow in the wedge-shaped region on both sides of the neutral line is due to acceleration of plasma by tangential magnetic stresses at the slow mode shocks extending form the X line

  6. Joint International Accelerator School

    CERN Multimedia

    CERN Accelerator School

    2014-01-01

    The CERN and US Particle Accelerator Schools recently organised a Joint International Accelerator School on Beam Loss and Accelerator Protection, held at the Hyatt Regency Hotel, Newport Beach, California, USA from 5-14 November 2014. This Joint School was the 13th in a series of such schools, which started in 1985 and also involves the accelerator communities in Japan and Russia.   Photo courtesy of Alfonse Pham, Michigan State University.   The school attracted 58 participants representing 22 different nationalities, with around half from Europe and the other half from Asia and the Americas. The programme comprised 26 lectures, each of 90 minutes, and 13 hours of case study. The students were given homework each day and had an opportunity to sit a final exam, which counted towards university credit. Feedback from the participants was extremely positive, praising the expertise and enthusiasm of the lecturers, as well as the high standard and quality of their lectures. Initial dis...

  7. Future accelerators: physics issues

    International Nuclear Information System (INIS)

    Bjorken, J.D.

    1977-11-01

    High energy physics of the future using future accelerators is discussed. The proposed machines and instruments, physics issues and opportunities including brief sketches of outstanding recent results, and the way the proposed machines address these issues are considered. 42 references

  8. Compact particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo-Decanini, Juan M.

    2017-08-29

    A compact particle accelerator having an input portion configured to receive power to produce particles for acceleration, where the input portion includes a switch, is provided. In a general embodiment, a vacuum tube receives particles produced from the input portion at a first end, and a plurality of wafer stacks are positioned serially along the vacuum tube. Each of the plurality of wafer stacks include a dielectric and metal-oxide pair, wherein each of the plurality of wafer stacks further accelerate the particles in the vacuum tube. A beam shaper coupled to a second end of the vacuum tube shapes the particles accelerated by the plurality of wafer stacks into a beam and an output portion outputs the beam.

  9. The accelerator breeder

    International Nuclear Information System (INIS)

    Johansson, E.

    1986-01-01

    Interactions of high-energy particles with atomic nuclei, in particular heavy ones, leads to a strong emission of neutrons. Preferably these high-energy particles are protons or deuterons obtained from a linear accelerator. The neutrons emitted are utilized in the conversion of U238 to Pu239 or of Th232 to U233. The above is the basis of the accelerator breeder, a concept studied abroad in many variants. No such breeder has, however, so far been built, but there exists vast practical experience on the neutron production and on the linear accelerator. Some of the variants mentioned are described in the report, after a presentation of general characteristics for the particle-nucleus interaction and for the linear accelerator. (author)

  10. Accelerate Water Quality Improvement

    Science.gov (United States)

    EPA is committed to accelerating water quality improvement and minimizing negative impacts to aquatic life from contaminants and other stressors in the Bay Delta Estuary by working with California Water Boards to strengthen water quality improvement plans.

  11. Rejuvenating CERN's Accelerators

    CERN Multimedia

    2004-01-01

    In the coming years and especially in 2005, CERN's accelerators are going to receive an extensive renovation programme to ensure they will perform reliably and effectively when the LHC comes into service.

  12. Wake field acceleration experiments

    International Nuclear Information System (INIS)

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics? I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs

  13. Accelerated test program

    Science.gov (United States)

    Ford, F. E.; Harkness, J. M.

    1977-01-01

    A brief discussion on the accelerated testing of batteries is given. The statistical analysis and the various aspects of the modeling that was done and the results attained from the model are also briefly discussed.

  14. IAE pulsed electrostatic accelerator

    International Nuclear Information System (INIS)

    Afanas'ev, V.P.; Ganzhelyuk, M.L.; Kozlov, L.D.; Koltypin, E.A.; Molchanov, Yu.D.; Otroshchenko, G.A.; Yan'kov, G.B.

    1976-01-01

    The modernized pulse electrostatic accelerator using the klystron ion grouping and the beam interruption system prior to acceleration is described. The accelerator is modernized in order to improve parameters of a current pulse and to decrease the background in the measurement room. The ion beam of needed dimensions is obtained with the help of a high-frequency source and a beam grouping and deflection system. The general view of the beam grouping and deflection system is shown. The ion beam forming process is considered in detail. The modernized electrostatic accelerator permits to obtain a pulse current with a pulse length of 1.5 ns and an amplitude of 1.5 - 2 μA. With the repetition frequency of 2 MHz, the average target current is about 6 μA

  15. Ionization front accelerator

    International Nuclear Information System (INIS)

    Olson, C.L.

    1975-01-01

    In a recently proposed linear collective accelerator, ions are accelerated in a steep, moving potential well created at the head of an intense relativistic electron beam. The steepness of the potential well and its motion are controlled by the external ionization of a suitable background gas. Calculations concerning optimum choices for the background gas and the ionization method are presented; a two-step photoionization process employing Cs vapor is proposed. In this process, a super-radiant light source is used to excite the gas, and a UV laser is used to photoionize the excited state. The appropriate line widths and coupled ionization growth rate equations are discussed. Parameter estimates are given for a feasibility experiment, for a 1 GeV proton accelerator, and for a heavy ion accelerator (50 MeV/nucleon uranium). (auth)

  16. HEAVY ION LINEAR ACCELERATOR

    Science.gov (United States)

    Van Atta, C.M.; Beringer, R.; Smith, L.

    1959-01-01

    A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.

  17. Advances in electrostatic accelerators

    International Nuclear Information System (INIS)

    Wegner, H.E.

    1975-01-01

    Advances in the design and performance of electrostatic accelerators since 1969 are reviewed with special emphasis on the ''forefront'' accelerators that are currently leading in voltage capability. A comparison of the acceleration tube design offered by the National Electrostatics Corporation and the High Voltage Engineering Corporation is also made. Other methods of increasing heavy ion energy by means of dual foil stripping are discussed as well as the performance of a newly developed sputter ion source for the production of negative heavy ions with reliability and flexibility that greatly exceeds all other present systems. Finally, new developments in terms of both booster systems and very high voltage electrostatic accelerators (25 to 60 MV) are discussed. (U.S.)

  18. Modelación con elementos finitos del agrietamiento en el hormigón por corrosión localizada en la armadura Finite element modeling of cracking in concrete due to localized corrosion in the reinforcement

    Directory of Open Access Journals (Sweden)

    J Castorena

    2007-04-01

    reinforcement, and concrete type and the longitude of corrosion, known as anodic longitude. The results show the great influence that has the localized corrosion (small-size anode vs large-size cathode on the prediction of rcrit, and that effect is only possible to analyze it in a three-dimensional way. Likewise, the efficiency of using the contact elements CONTA174 to represent the growth of oxide is shown. The obtained model explains in 92% the phenomenon and which is compared with experimental results found in literature

  19. Iteration and accelerator dynamics

    International Nuclear Information System (INIS)

    Peggs, S.

    1987-10-01

    Four examples of iteration in accelerator dynamics are studied in this paper. The first three show how iterations of the simplest maps reproduce most of the significant nonlinear behavior in real accelerators. Each of these examples can be easily reproduced by the reader, at the minimal cost of writing only 20 or 40 lines of code. The fourth example outlines a general way to iteratively solve nonlinear difference equations, analytically or numerically

  20. High energy medical accelerators

    International Nuclear Information System (INIS)

    Mandrillon, P.

    1990-01-01

    The treatment of tumours with charged particles, ranging from protons to 'light ions' (carbon, oxygen, neon), has many advantages, but up to now has been little used because of the absence of facilities. After the successful pioneering work carried out with accelerators built for physics research, machines dedicated to this new radiotherapy are planned or already in construction. These high energy medical accelerators are presented in this paper. (author) 15 refs.; 14 figs.; 8 tabs

  1. Vancouver Accelerator Conference

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1985-06-15

    Anyone who contends that particle physics is conducted in an ivory tower, not contributing to other fields of science or to humanity at large, should have attended the 1985 Particle Accelerator Conference in Vancouver. Over a thousand participants contributed 781 papers and only a fraction were actually related to accelerators for high energy physics. The majority of present developments are in the service of other fields of science, for alternative power sources, for medicine, for industrial applications, etc.

  2. A symmetrical rail accelerator

    International Nuclear Information System (INIS)

    Igenbergs, E.

    1991-01-01

    This paper reports on the symmetrical rail accelerator that has four rails, which are arranged symmetrically around the bore. The opposite rails have the same polarity and the adjacent rails the opposite polarity. In this configuration the radial force acting upon the individual rails is significantly smaller than in a conventional 2-rail configuration and a plasma armature is focussed towards the axis of the barrel. Experimental results indicate a higher efficiency compared to a conventional rail accelerator

  3. Ion optics for accelerators

    International Nuclear Information System (INIS)

    Enge, H.A.

    1974-01-01

    A review is given of ion-optic devices used in particle accelerators, including electrostatic lenses, magnetic quadrupoles, and deflecting magnets. Tube focusing in dc accelerators is also treated, and a novel scheme for shaping the electrodes to produce strong focusing is described. The concepts of emittance (phase space) and emittance conservation are briefly discussed. Chromatic and spatial aberrations are introduced, and it is shown how they can be calculated and sometimes substantially reduced. Some examples are given

  4. An active particle accelerator

    International Nuclear Information System (INIS)

    Goldman, T.

    1991-01-01

    Although a static charge is difficult to maintain on macroscopic particles, it is straightforward to construct a small object with a regularly oscillating electric dipole moment. For objects of a given size, one may then construct an accelerator by appropriately matching the frequency and separations of an external array of electrodes to this size. Physically feasible size ranges, an accelerator design, and possible applications of such systems are discussed. 8 refs., 9 figs

  5. Vancouver Accelerator Conference

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    Anyone who contends that particle physics is conducted in an ivory tower, not contributing to other fields of science or to humanity at large, should have attended the 1985 Particle Accelerator Conference in Vancouver. Over a thousand participants contributed 781 papers and only a fraction were actually related to accelerators for high energy physics. The majority of present developments are in the service of other fields of science, for alternative power sources, for medicine, for industrial applications, etc

  6. CEBAF Accelerator Achievements

    International Nuclear Information System (INIS)

    Chao, Y C; Drury, M; Hovater, C; Hutton, A; Krafft, G A; Poelker, M; Reece, C; Tiefenback, M

    2011-01-01

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  7. Collective field accelerator

    International Nuclear Information System (INIS)

    Luce, J.S.

    1978-01-01

    A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a ν/γ of approx. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam

  8. CEBAF: Accelerating cavities look good

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1990-09-15

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications.

  9. CEBAF: Accelerating cavities look good

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications

  10. JAERI 20 MV tandem accelerator

    International Nuclear Information System (INIS)

    Tsukada, Kineo; Harada, Kichinosuke

    1977-01-01

    Accelerators have been developed as the experimental apparatuses for the studies on nuclei and elementary particles. One direction of the development is the acceleration of protons and electrons to more and more high energy, and another direction is the acceleration of heavy ions up to uranium to several MeV up to several hundreds MeV. However recently, accelerators are used as the useful tools for the studies in wider fields. There are electrostatic acceleration and high frequency acceleration in ion acceleration, and at present, super-large accelerators are high frequency acceleration type. In Japan Atomic Energy Research Institute, it was decided in 1975 to construct an electrostatic accelerator of tandem type in order to accelerate heavy ions. In case of the electrostatic acceleration, the construction is relatively simple, the acceleration of heavy ions is easy, the property of the ion beam is very good, and the energy is stable. Especially, the tandem type is convenient for obtaining high energy. The tandem accelerator of 20 MV terminal voltage was ordered from the National Electrostatics Corp., USA, and is expected to be completed in 1978. The significance of heavy ion acceleration in the development and research of atomic energy, tandem van de Graaff accelerators, the JAERI 20MV tandem accelerator, and the research project with this accelerator are described. (Kako, I.)

  11. Radiation protection of the operation of accelerator facilities. On high energy proton and electron accelerators

    International Nuclear Information System (INIS)

    Kondo, Kenjiro

    1997-01-01

    Problems in the radiation protection raised by accelerated particles with energy higher than several hundreds MeV in strong accelerator facilities were discussed in comparison with those with lower energy in middle- and small-scale facilities. The characteristics in the protection in such strong accelerator facilities are derived from the qualitative changes in the interaction between the high energy particles and materials and from quantitative one due to the beam strength. In the former which is dependent on the emitting mechanism of the radiation, neutron with broad energy spectrum and muon are important in the protection, and in the latter, levels of radiation and radioactivity which are proportional to the beam strength are important. The author described details of the interaction between high energy particles and materials: leading to the conclusion that in the electron accelerator facilities, shielding against high energy-blemsstrahlung radiation and -neutron is important and in the proton acceleration, shielding against neutron is important. The characteristics of the radiation field in the strong accelerator facilities: among neutron, ionized particles and electromagnetic wave, neutron is most important in shielding since it has small cross sections relative to other two. Considerations for neutron are necessary in the management of exposure. Multiplicity of radionuclides produced: which is a result of nuclear spallation reaction due to high energy particles, especially to proton. Radioactivation of the accelerator equipment is a serious problem. Other problems: the interlock systems, radiation protection for experimenters and maintenance of the equipment by remote systems. (K.H.). 11 refs

  12. APT accelerator technology

    International Nuclear Information System (INIS)

    Schneider, J. David

    1996-01-01

    The proposed accelerator production of tritium (APT) project requires an accelerator that provides a cw proton beam of 100 m A at 1300 MeV. Since the majority of the technical risk of a high-current cw (continuous-wave, 100% DF) accelerator resides in the low-energy section, Los Alamos is building a 20 MeV duplicate of the accelerator front end to confirm design codes, beam performance, and demonstrate operational reliability. We report on design details of this low-energy demonstration accelerator (LEDA) and discuss the integrated design of the full accelerator for the APT plant. LEDA's proton injector is under test and has produced more than 130 mA at 75 keV. Fabrication is proceeding on a 6.7- MeV, 8-meter-long RFQ, and detailed design is underway on coupled-cavity drift-tube linac (CCDTL) structures. In addition, detailed design and technology experiments are underway on medium-beta superconducting cavities to assess the feasibility of replacing the conventional (room-temperature copper) high-energy linac with a linac made of niobium superconducting RF cavities. (author)

  13. Laser wakefield acceleration

    International Nuclear Information System (INIS)

    Esarey, E.; Ting, A.; Sprangle, P.

    1989-01-01

    The laser wakefield accelerator (LWFA) is a novel plasma based electron acceleration scheme which utilizes a relativistic optical guiding mechanism for laser pulse propagation. In the LWFA, a short, high power, single frequency laser pulse is propagated through a plasma. As the laser pulse propagates, its radial and axial ponderomotive forces nonresonantly generate large amplitude plasma waves (wakefields) with a phase velocity equal to the group velocity of the pulse. A properly phased electron bunch may then be accelerated by the axial wakefield and focused by the transverse wakefield. Optical guiding of the laser pulse in the plasma is necessary in order to achieve high energies in a single stage of acceleration. At sufficiently high laser powers, optical guiding may be achieved through relativistic effects associated with the plasma electrons. Preliminary analysis indicates that this scheme may overcome some of the difficulties present in the plasma beat wave accelerator and in the plasma wakefield accelerator. Analytical and numerical calculations are presented which study both laser pulse propagation within a plasma as well as the subsequent generation of large amplitude plasma waves. In addition, the generation of large amplitude plasma waves in regimes where the plasma waves become highly nonlinear is examined

  14. IMPELA electron accelerators for industrial radiation processing

    International Nuclear Information System (INIS)

    Hare, G.E.

    1990-01-01

    IMPELA electron accelerators are derived from a common basic design of rf accelerating structure which is capable of handling beams with powers from 20 to 250 kW at 5 to 18 MeV. A prototype has been built which operates at 50 kW and 10 MeV. The paper describes the major elements of the system with particular reference to features which assist in maintaining irradiation quality, simple operation and high reliability. A cost model based on the prototype is used to demonstrate the economies of scale available and the impact of local prices for utilities. (author)

  15. Generic device controller for accelerator control systems

    International Nuclear Information System (INIS)

    Mariotti, R.; Buxton, W.; Frankel, R.; Hoff, L.

    1987-01-01

    A new distributed intelligence control system has become operational at the AGS for transport, injection, and acceleration of heavy ions. A brief description of the functionality of the physical devices making up the system is given. An attempt has been made to integrate the devices for accelerator specific interfacing into a standard microprocessor system, namely, the Universal Device Controller (UDC). The main goals for such a generic device controller are to provide: local computing power; flexibility to configure; and real time event handling. The UDC assemblies and software are described

  16. Continuity of Accelerator Operations during an Extended Pandemic

    International Nuclear Information System (INIS)

    Noel Okay

    2010-01-01

    The Operations group for the Continuous Electron Accelerator Facility in Newport News Virginia has developed a Continuity of Operations plan for pandemic conditions when high absenteeism may impact accelerator control room operations. Protocols to address both the potential spread of illnesses in the control room environment as well as maintaining minimum staffing requirements for contiguous accelerator operation will be presented. During acute pandemic conditions local government restrictions may prevent continued operations but during extended periods of high absenteeism accelerator operations can continue when some added precautionary measures and staffing adjustments are made in the way business is done.

  17. New generation of compact electron accelerators for radiation technologies

    International Nuclear Information System (INIS)

    Auslender, V.L.; Balakin, V.E.; Kraynov, G.S.

    1995-01-01

    Compact electron accelerators with energy range 0.25-1.0 MeV and beam power up to 32 kw are described. The feeding high voltage is formed by converter (working frequency 20 khz), coreless step-up transformer and a set of rectifying sections. The rectifying multiplier circuit used in rectifying sections permits to reach voltage gradient along accelerator's axis up to 14 kV/cm. The accelerators with vertical and horizontal position are described. The accelerators can be produced together with local radiation shielding and various underbeam transportation systems for irradiation of different products. Such version can be installed in any room facing general requirements for electric equipment

  18. Accelerator research studies: Progress report, Task B

    International Nuclear Information System (INIS)

    1985-06-01

    The main objectives in Task B of the research program are summarized as follows: (1) studies of the collective acceleration of positive ions from a localized plasma source by an intense relativistic electron beam (IREB), (2) studies of ways in which external control may be achieved over the electron beam front in order to achieve higher ion energies - the Beam Front Accelerator (BFA) concept, and (3) study of electron and ion beam generation in a new kind of compact pulsed accelerator in which energy is stored inductively and switched using a plasma focus opening switch. During the past year, substantial progress was made in each of these areas. Our exploratory research on the collective acceleration of laser-produced ions has confirmed the acceleration of C, Al, and Fe ions to peak energies in excess of 10 MeV/amu. In addition, studies of the relation between collective ion acceleration and electron beam propagation in vacuum have shed new light on the experimental processes that lead to energy transfer from electrons to ions. Meanwhile, extensive progress has been made in our attempts to use analytical theory and numerical simulation to model ion acceleration in these systems. Our resultant improved understanding of the processes that limit the peak ion energy has had a profound impact on our plans for further research in this area. Studies of the Compact Pulsed Accelerator have included both ion and electron beam extraction from the device. Its potential to reduce the volume of pulse power sources by an order of magnitude has already been demonstrated, and plans are currently underway to scale the experiment up to voltages in the 1 MV range

  19. Photon acceleration in laser wakefield accelerators

    International Nuclear Information System (INIS)

    Trines, R. M. G. M.

    2007-01-01

    If the index of a refraction of a dispersive medium, such as a plasma, changes in time, it can be used to change the frequency of light propagating through the medium. This effect is called photon acceleration. It has been predicted in both theory and simulations, and also been demonstrated experimentally for the case of moving ionization fronts in gases (the so-called ionization blueshift) as well as for laser-driven wakefields.Here, we present studies of photon acceleration in laser-driven plasma wakefields. The unique spectral characteristics of this process will be discussed, to distinguish it from e.g. photon acceleration by ionization fronts, frequency domain interferometry or self-phase modulation. The dynamics of the photons in laser-wakefield interaction are studied through both regular particle-in-cell and wave-kinetic simulations. The latter approach provides a powerful, versatile, and easy-to-use method to track the propagation of individual spectral components, providing new insight into the physics of laser-plasma interaction. Theory, simulations and experimental results will be brought together to provide a full understanding of the dynamics of a laser pulse in its own wakefield.Even though the wave-kinetic approach mentioned above has mainly been developed for the description of laser-plasma interaction, it can be applied to a much wider range of fast wave-slow wave interaction processes: Langmuir waves-ion acoustic waves, drift waves-zonal flow, Rossby waves-zonal flow, or even photons-gravitational waves. Several recent results in these areas will be shown, often with surprising results

  20. Accelerator business in Japan expanding

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Accelerators have become to be used increasingly in Japan in such fields as medicine, physics research and industry. This has caused stiff competition for market share by the manufacturers of accelerators. Electron beam accelerators for industrial use provide an indispensable means for adding values to products, for example, electric cables with incombustible insulators. Linear accelerators for the nondestructive inspection of nuclear components have been widely installed at equipment manufacturing plants. Active efforts have been exerted to develop small synchrotron radiation accelerators for next generation electronic industry. Cyclotrons for producing short life radioisotopes for medical diagnosis and electron beam accelerators for radiation therapy are also used routinely. The suppliers of accelerators include the companies manufacturing heavy electric machinery, heavy machinery and the engineering division of steelmakers. Accelerator physics is being formed, but universities do not yet offer the course regarding accelerators. Accelerator use in Japan and the trend of accelerator manufacturers are reported. (K.I.)

  1. Design & simulation of a 800 kV dynamitron accelerator by CST studio

    Directory of Open Access Journals (Sweden)

    A M Aghayan

    2015-09-01

    Full Text Available Nowadays, middle energy electrostatic accelerators in industries are widely used due to their high efficiency and low cost compared with other types of accelerators. In this paper, the importance and applications of electrostatic accelerators with 800 keV energy are studied. Design and simulation of capacitive coupling of a dynamitron accelerator is proposed. Furthermore, accelerating tube are designed and simulated by means of CST Suit Studio

  2. Beam transport through electrostatic accelerators and matching into post accelerators

    International Nuclear Information System (INIS)

    Larson, J.D.

    1986-01-01

    Ion beam transport through electrostatic acceleration is briefly reviewed. Topics discussed include injection, matching into the low-energy acceleration stage, matching from the terminal stripper into the high-energy stage, transport to a post accelerator, space charge, bunching isochronism, dispersion and charge selection. Beam transport plans for the proposed Vivitron accelerator are described. (orig.)

  3. Synergia CUDA: GPU-accelerated accelerator modeling package

    International Nuclear Information System (INIS)

    Lu, Q; Amundson, J

    2014-01-01

    Synergia is a parallel, 3-dimensional space-charge particle-in-cell accelerator modeling code. We present our work porting the purely MPI-based version of the code to a hybrid of CPU and GPU computing kernels. The hybrid code uses the CUDA platform in the same framework as the pure MPI solution. We have implemented a lock-free collaborative charge-deposition algorithm for the GPU, as well as other optimizations, including local communication avoidance for GPUs, a customized FFT, and fine-tuned memory access patterns. On a small GPU cluster (up to 4 Tesla C1070 GPUs), our benchmarks exhibit both superior peak performance and better scaling than a CPU cluster with 16 nodes and 128 cores. We also compare the code performance on different GPU architectures, including C1070 Tesla and K20 Kepler.

  4. Experimental study of ion heating and acceleration during magnetic reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, S.C.

    2000-01-28

    This dissertation reports an experimental study of ion heating and acceleration during magnetic reconnection, which is the annihilation and topological rearrangement of magnetic flux in a conductive plasma. Reconnection is invoked often to explain particle heating and acceleration in both laboratory and naturally occurring plasmas. However, a simultaneous account of reconnection and its associated energy conversion has been elusive due to the extreme inaccessibility of reconnection events, e.g. in the solar corona, the Earth's magnetosphere, or in fusion research plasmas. Experiments for this work were conducted on MRX (Magnetic Reconnection Experiment), which creates a plasma environment allowing the reconnection process to be isolated, reproduced, and diagnosed in detail. Key findings of this work are the identification of local ion heating during magnetic reconnection and the determination that non-classical effects must provide the heating mechanism. Measured ion flows are sub-Alfvenic and can provide only slight viscous heating, and classical ion-electron interactions can be neglected due to the very long energy equipartition time. The plasma resistivity in the reconnection layer is seen to be enhanced over the classical value, and the ion heating is observed to scale with the enhancement factor, suggesting a relationship between the magnetic energy dissipation mechanism and the ion heating mechanism. The observation of non-classical ion heating during reconnection has significant implications for understanding the role played by non-classical dissipation mechanisms in generating fast reconnection. The findings are relevant for many areas of space and laboratory plasma research, a prime example being the currently unsolved problem of solar coronal heating. In the process of performing this work, local measurements of ion temperature and flows in a well-characterized reconnection layer were obtained for the first time in either laboratory or observational

  5. Experimental study of ion heating and acceleration during magnetic reconnection

    International Nuclear Information System (INIS)

    Hsu, S.C.

    2000-01-01

    This dissertation reports an experimental study of ion heating and acceleration during magnetic reconnection, which is the annihilation and topological rearrangement of magnetic flux in a conductive plasma. Reconnection is invoked often to explain particle heating and acceleration in both laboratory and naturally occurring plasmas. However, a simultaneous account of reconnection and its associated energy conversion has been elusive due to the extreme inaccessibility of reconnection events, e.g. in the solar corona, the Earth's magnetosphere, or in fusion research plasmas. Experiments for this work were conducted on MRX (Magnetic Reconnection Experiment), which creates a plasma environment allowing the reconnection process to be isolated, reproduced, and diagnosed in detail. Key findings of this work are the identification of local ion heating during magnetic reconnection and the determination that non-classical effects must provide the heating mechanism. Measured ion flows are sub-Alfvenic and can provide only slight viscous heating, and classical ion-electron interactions can be neglected due to the very long energy equipartition time. The plasma resistivity in the reconnection layer is seen to be enhanced over the classical value, and the ion heating is observed to scale with the enhancement factor, suggesting a relationship between the magnetic energy dissipation mechanism and the ion heating mechanism. The observation of non-classical ion heating during reconnection has significant implications for understanding the role played by non-classical dissipation mechanisms in generating fast reconnection. The findings are relevant for many areas of space and laboratory plasma research, a prime example being the currently unsolved problem of solar coronal heating. In the process of performing this work, local measurements of ion temperature and flows in a well-characterized reconnection layer were obtained for the first time in either laboratory or observational

  6. Injection and laser acceleration of ions based on the resonant surface photoionization

    International Nuclear Information System (INIS)

    Antsiferov, V.V.; Smirnov, G.I.; Telegin, G.G.

    1993-01-01

    The collective effects have been investigated of the injection and acceleration of the ion beams due to the resonant surface photoionization. The considered scheme of the laser accelerator allows to obtain positive ions with relativistic velocities. 11 refs., 2 figs

  7. Status of the Cracow electrostatic accelerator project

    International Nuclear Information System (INIS)

    Hebenstreit, J.R.; Kopczynski, J.P.

    1981-01-01

    The range of nuclear reaction measurements and applied interdisciplinary research performed earlier with accelerated particles in this Institute were strongly limited the accelerators being at disposal: an open air 1 MV Van de Graaff generator in the Jagellonian University and the cyclotron U-120 in the neighboring Institute of Nuclear Physics. Due to financial problems connected with buying a new ready accelerator, an approval was obtained for carrying out a detailed design study on condition that the accelerator should be constructed in the Institute and should be built of construction elements accessible in Poland. Having obtained the final approval of the project - tandem accelerator with 5 MV pressurized Van de Graaff generator, the construction was started in 1980. The investment period should be finished in 1982 with a single ended 5 MV accelerator. Simultaneously, the calculations and preparation for a tandem mode was begun. The gas handling system has just been made by the home industry and should be mounted and tested in 1981. The reconstruction of the building should be performed in the same time

  8. ORNL pellet acceleration program

    International Nuclear Information System (INIS)

    Foster, C.A.; Milora, S.L.

    1978-01-01

    The Oak Ridge National Laboratory (ORNL) pellet fueling program is centered around developing equipment to accelerate large pellets of solidified hydrogen to high speeds. This equipment will be used to experimentally determine pellet-plasma interaction physics on contemporary tokamaks. The pellet experiments performed on the Oak Ridge Tokamak (ORMAK) indicated that much larger, faster pellets would be advantageous. In order to produce and accelerate pellets of the order of 1 to 6 mm in diameter, two apparatuses have been designed and are being constructed. The first will make H 2 pellets by extruding a filament of hydrogen and mechanically chopping it into pellets. The pellets formed will be mechanically accelerated with a high speed arbor to a speed of 950 m/sec. This technique may be extended to speeds up to 5000 m/sec, which makes it a prime candidate for a reactor fueling device. In the second technique, a hydrogen pellet will be formed, loaded into a miniature rifle, and accelerated by means of high pressure hydrogen gas. This technique should be capable of speeds of the order of 1000 m/sec. While this technique does not offer the high performance of the mechanical accelerator, its relative simplicity makes it attractive for near-term experiments

  9. Accelerator development at Bates

    International Nuclear Information System (INIS)

    Sargent, C.P.

    1983-01-01

    The past year has seen the completion of a major expansion of the Bates Accelerator Laboratory. A second experimental hall, South Hall, and several magnetic spectrometers have been constructed. The accelerator's maximum energy has been raised from 400 to 750 MeV by means of beam recirculation. A current two-year project for the fabrication of an additional RF transmitter plus a 30% increase in RF peak power capability will increase energy further to ca. 1 GeV. During the same period pulse-to-pulse beam sharing between the high-resolution spectrometer area and South Hall will become available. In January 1981 the Laboratory submitted their ''Proposal for a Long-Range Expansion Program'' to DOE-NSF. The proposed development consists of three stages. Stage I calls for the addition of a pulse stretcher ring to furnish a CW beam to the South Hall beam lines. Additional experimental space for internal target experiments and photon tagging research are also included. Stage II increases the accelerator energy to 2.1 GeV (at 140 microamps) by means of a five-pass head-to-tail recirculator. Stage III is, at this time, a plan rather than a proposal. It increases accelerator energy to 4 GeV by extending the accelerator length and power and adds another pulse stretcher ring and three new experimental areas for the higher energy work. This paper discusses each of these stages in detail and recommends their funding and scheduling

  10. High energy plasma accelerators

    International Nuclear Information System (INIS)

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ω 0 , kappa 0 and ω 1 , kappa 1 shone on a plasma with frequency separation equal to the electron plasma frequency ω/sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ω/sub pe//e of the order of 1GeV/cm for a plasma density of 10 18 cm -3 through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed

  11. Linear induction accelerators

    International Nuclear Information System (INIS)

    Briggs, R.J.

    1986-06-01

    The development of linear induction accelerators has been motivated by applications requiring high-pulsed currents of charged particles at voltages exceeding the capability of single-stage, diode-type accelerators and at currents too high for rf accelerators. In principle, one can accelerate charged particles to arbitrarily high voltages using a multi-stage induction machine, but the 50-MeV, 10-kA Advanced Test Accelerator (ATA) at LLNL is the highest voltage machine in existence at this time. The advent of magnetic pulse power systems makes sustained operation at high-repetition rates practical, and this capability for high-average power is very likely to open up many new applications of induction machines in the future. This paper surveys the US induction linac technology with primary emphasis on electron machines. A simplified description of how induction machines couple energy to the electron beam is given, to illustrate many of the general issues that bound the design space of induction linacs

  12. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  13. Flow accelerated organic coating degradation

    Science.gov (United States)

    Zhou, Qixin

    Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as

  14. Accelerators for atomic energy research

    International Nuclear Information System (INIS)

    Shibata, Tokushi

    1999-01-01

    The research and educational activities accomplished using accelerators for atomic energy research were studied. The studied items are research subjects, facility operation, the number of master theses and doctor theses on atomic energy research using accelerators and the future role of accelerators in atomic energy research. The strategy for promotion of the accelerator facility for atomic energy research is discussed. (author)

  15. Accelerators in Science and Technology

    CERN Document Server

    Kailas, S

    2002-01-01

    Accelerators built for basic research in frontier areas of science have become important and inevitable tools in many areas of science and technology. Accelerators are examples of science driven high technology development. Accelerators are used for a wide ranging applications, besides basic research. Accelerator based multidisciplinary research holds great promise

  16. Plasma-based accelerator structures

    International Nuclear Information System (INIS)

    Schroeder, Carl B.

    1999-01-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas

  17. Hyperfractionated accelerated radiation therapy plus cetuximab plus cisplatin chemotherapy in locally advanced inoperable squamous cell carcinoma of the head and neck. Final 5-year results of a phase II study

    Energy Technology Data Exchange (ETDEWEB)

    Kuhnt, Thomas [University of Leipzig, Department of Imaging and Radiation Medicine, Clinic of Radiooncology, Leipzig (Germany); Schreiber, Andreas [Private Praxis for Radio Oncology Dresden, Dresden (Germany); Pirnasch, Anett [University of Rostock, Department of Radiation Oncology, Rostock (Germany); Hautmann, Matthias G. [University of Regensburg, Department of Radiotherapy, Regensburg (Germany); Hass, Peter [Otto von Guericke University of Magdeburg, Department of Radiotherapy, Magdeburg (Germany); Sieker, Frank P. [Martin Luther University of Halle-Wittenberg, Department of Radiotherapy, Halle (Saale) (Germany); Engenhart-Cabillic, Rita [Philipps University Marburg, Department of Radiotherapy, Marburg (Germany); Richter, Michael [Coordination Centre for Clinical Trials Halle, Halle (Saale) (Germany); Dellas, Kathrin; Dunst, Juergen [University of Kiel, Department of Radiation Oncology, Kiel (Germany)

    2017-09-15

    Cetuximab (CET) is a potent inhibitor of the epidermal growth factor receptor and has been shown to have activity in squamous cell carcinoma of the head and neck (SCCHN). We conducted a single-arm phase II trial of a combination therapy comprising cisplatin (CIS), CET and hyperfractionated accelerated radiotherapy (HART). Patients with UICC stage III or IVA/B, M0 SCCHN were enrolled and treated with an initial dose of CET (400 mg/m{sup 2}) and then with a weekly dosage of 250 mg/m{sup 2} during HART. HART was started with a prescribed dosage of 2.0 Gy per day for 3 weeks, followed by 1.4 Gy twice daily to a total dose of 70.6 Gy to the gross tumour volume. CIS (40 mg/m{sup 2}) was administered weekly (days 1, 8, 15, 22, 29 and 36). The primary objective of the phase II study was to determine the 2-year progression-free survival (PFS). Between November 2007 and November 2010, a total of 74 patients were enrolled in the study, of whom 65 were evaluable (83% were men). Median age was 56 years (range 37-69 years). An Oropharyngeal primary tumour was diagnosed in 49%, T4a,b in 65% and N2/3 in 96% of the patients. Of these patients, 85% were smokers or ex-smokers. Complete remission (CR) was observed in 23 patients (35%). The most common toxicity grade was ≥3, including mucositis (58%) and dysphagia (52%). The 2- and 5-year overall survival rates were 64 and 41%, the 2- and 5-year PFS rates were 45 and 32%, and the 2- and 5-year locoregional control rates were 47 and 33%, respectively. The combination of weekly CIS with HART plus CET is a feasible regimen for these unfavourable smoking-induced cancers. However, the parallel US study (RTOG 0522) showed no advantage of the enhanced triple therapy compared to chemoradiotherapy alone. (orig.) [German] Cetuximab (CET) ist ein potenter Inhibitor des epidermalen Wachstumsfaktor-Rezeptors, der schon bei Plattenepithelkarzinomen des Kopf-Hals-Bereichs (SCCHN) Wirkung gezeigt hat. Wir fuehrten eine prospektive, einarmige Phase

  18. Two Step Acceleration Process of Electrons in the Outer Van Allen Radiation Belt by Time Domain Electric Field Bursts and Large Amplitude Chorus Waves

    Science.gov (United States)

    Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.; Lejosne, S.

    2014-12-01

    A huge number of different non-linear structures (double layers, electron holes, non-linear whistlers, etc) have been observed by the electric field experiment on the Van Allen Probes in conjunction with relativistic electron acceleration in the Earth's outer radiation belt. These structures, found as short duration (~0.1 msec) quasi-periodic bursts of electric field in the high time resolution electric field waveform, have been called Time Domain Structures (TDS). They can quite effectively interact with radiation belt electrons. Due to the trapping of electrons into these non-linear structures, they are accelerated up to ~10 keV and their pitch angles are changed, especially for low energies (˜1 keV). Large amplitude electric field perturbations cause non-linear resonant trapping of electrons into the effective potential of the TDS and these electrons are then accelerated in the non-homogeneous magnetic field. These locally accelerated electrons create the "seed population" of several keV electrons that can be accelerated by coherent, large amplitude, upper band whistler waves to MeV energies in this two step acceleration process. All the elements of this chain acceleration mechanism have been observed by the Van Allen Probes.

  19. Diplopia due to Dacryops

    Directory of Open Access Journals (Sweden)

    Rahmi Duman

    2013-01-01

    Full Text Available Dacryops is a lacrimal ductal cyst. It is known that it can cause globe displacement, motility restriction, and proptosis because of the mass effect. Diplopia due to dacryops has not been reported previously. Here, we present a 57-year-old man with binocular horizontal diplopia that occurred during left direction gaze due to dacryops.

  20. A nationwide quality improvement project to accelerate Ghana's progress toward Millennium Development Goal Four: design and implementation progress.

    Science.gov (United States)

    Twum-Danso, Nana A Y; Akanlu, George B; Osafo, Enoch; Sodzi-Tettey, Sodzi; Boadu, Richard O; Atinbire, Solomon; Adondiwo, Ane; Amenga-Etego, Isaac; Ashagbley, Francis; Boadu, Eric A; Dasoberi, Ireneous; Kanyoke, Ernest; Yabang, Elma; Essegbey, Ivan T; Adjei, George A; Buckle, Gilbert B; Awoonor-Williams, J Koku; Nang-Beifubah, Alexis; Twumasi, Akwasi; McCannon, C Joseph; Barker, Pierre M

    2012-12-01

    The gap between evidence-based guidelines and practice of care is reflected, in low- and middle-income countries, by high rates of maternal and child mortality and limited effectiveness of large-scale programing to decrease those rates. We designed a phased, rapid, national scale-up quality improvement (QI) intervention to accelerate the achievement of Millennium Development Goal Four in Ghana. Our intervention promoted systems thinking, active participation of managers and frontline providers, generation and testing of local change ideas using iterative learning from transparent district and local data, local ownership and sustainability. After 50 months of implementation, we have completed two prototype learning phases and have begun regional spread phases to all health facilities in all 38 districts of the three northernmost regions and all 29 Catholic hospitals in the remaining regions of the country. To accelerate the spread of improvement, we developed 'change packages' of rigorously tested process changes along the continuum of care from pregnancy to age 5 in both inpatient and outpatient settings. The primary successes for the project so far include broad and deep adoption of QI by local stakeholders for improving system performance, widespread capacitation of leaders, managers and frontline providers in QI methods, incorporation of local ideas into change packages and successful scale-up to approximately 25% of the country's districts in 3 years. Implementation challenges include variable leadership uptake and commitment at the district level, delays due to recruiting and scheduling barriers, weak data systems and repeated QI training due to high staff turnover.