Science.gov

Sample records for neutron beam applications

  1. Application of Pixel-cell Detector Technology for Advanced Neutron Beam Monitors

    SciTech Connect

    Kopp, Daniel M.

    2011-01-11

    Application of Pixel-Cell Detector Technology for Advanced Neutron Beam Monitors Specifications of currently available neutron beam detectors limit their usefulness at intense neutron beams of large-scale national user facilities used for the advanced study of materials. A large number of neutron-scattering experiments require beam monitors to operate in an intense neutron beam flux of >10E+7 neutrons per second per square centimeter. For instance, a 4 cm x 4 cm intense beam flux of 6.25 x 10E+7 n/s/cm2 at the Spallation Neutron Source will put a flux of 1.00 x 10E+9 n/s at the beam monitor. Currently available beam monitors with a typical efficiency of 1 x 10E-4 will need to be replaced in less than two years of operation due to wire and gas degradation issues. There is also a need at some instruments for beam position information that are beyond the capabilities of currently available He-3 and BF3 neutron beam monitors. ORDELA, Inc.’s research under USDOE SBIR Grant (DE-FG02-07ER84844) studied the feasibility of using pixel-cell technology for developing a new generation of stable, long-life neutron beam monitors. The research effort has led to the development and commercialization of advanced neutron beam detectors that will directly benefit the Spallation Neutron Source and other intense neutron sources such as the High Flux Isotope Reactor. A prototypical Pixel-Cell Neutron Beam Monitor was designed and constructed during this research effort. This prototype beam monitor was exposed to an intense neutron beam at the HFIR SNS HB-2 test beam site. Initial measurements on efficiency, uniformity across the detector, and position resolution yielded excellent results. The development and test results have provided the required data to initiate the fabrication and commercialization of this next generation of neutron-detector systems. ORDELA, Inc. has (1) identified low-cost design and fabrication strategies, (2) developed and built pixel-cell detectors and

  2. Characterization of deuterium beam operation on RHEPP-1 for future neutron generation applications.

    SciTech Connect

    Schall, Michael; Cooper, Gary Wayne; Renk, Timothy Jerome

    2009-12-01

    We investigate the potential for neutron generation using the 1 MeV RHEPP-1 intense pulsed ion beam facility at Sandia National Laboratories for a number of emerging applications. Among these are interrogation of cargo for detection of special nuclear materials (SNM). Ions from single-stage sources driven by pulsed power represent a potential source of significant neutron bursts. While a number of applications require higher ion energies (e.g. tens of MeV) than that provided by RHEPP-1, its ability to generate deuterium beams allow for neutron generation at and below 1 MeV. This report details the successful generation and characterization of deuterium ion beams, and their use in generating up to 3 x 10{sup 10} neutrons into 4{pi} per 5kA ion pulse.

  3. Neutron beam measurement dosimetry

    SciTech Connect

    Amaro, C.R.

    1995-11-01

    This report describes animal dosimetry studies and phantom measurements. During 1994, 12 dogs were irradiated at BMRR as part of a 4 fraction dose tolerance study. The animals were first infused with BSH and irradiated daily for 4 consecutive days. BNL irradiated 2 beagles as part of their dose tolerance study using BPA fructose. In addition, a dog at WSU was irradiated at BMRR after an infusion of BPA fructose. During 1994, the INEL BNCT dosimetry team measured neutron flux and gamma dose profiles in two phantoms exposed to the epithermal neutron beam at the BMRR. These measurements were performed as a preparatory step to the commencement of human clinical trials in progress at the BMRR.

  4. Neutron beam testing of triblades

    SciTech Connect

    Michalak, Sarah E; Du Bois, Andrew J; Storlie, Curtis B; Rust, William N; Du Bois, David H; Modl, David G; Quinn, Heather M; Blanchard, Sean P; Manuzzato, Andrea

    2010-12-16

    Four IBM Triblades were tested in the Irradiation of Chips and Electronics facility at the Los Alamos Neutron Science Center. Triblades include two dual-core Opteron processors and four PowerXCell 8i (Cell) processors. The Triblades were tested in their field configuration while running different applications, with the beam aimed at the Cell processor or the Opteron running the application. Testing focused on the Cell processors, which were tested while running five different applications and an idle condition. While neither application nor Triblade was statistically important in predicting the hazard rate, the hazard rate when the beam was aimed at the Opterons was significantly higher than when it was aimed at the Cell processors. In addition, four Cell blades (one in each Triblade) suffered voltage shorts, leading to their inoperability. The hardware tested is the same as that in the Roadrunner supercomputer.

  5. Design of multidirectional neutron beams for boron neutron capture synovectomy

    SciTech Connect

    Gierga, D.P.; Yanch, J.C.; Shefer, R.E.

    1997-12-01

    Boron neutron capture synovectomy (BNCS) is a potential application of the {sup 10}B(n, a) {sup 7}Li reaction for the treatment of rheumatoid arthritis. The target of therapy is the synovial membrane. Rheumatoid synovium is greatly inflamed and is the source of the discomfort and disability associated with the disease. The BNCS proposes to destroy the synovium by first injecting a boron-labeled compound into the joint space and then irradiating the joint with a neutron beam. This study discusses the design of a multidirectional neutron beam for BNCS.

  6. Neutron beam imaging with GEM detectors

    NASA Astrophysics Data System (ADS)

    Albani, G.; Croci, G.; Cazzaniga, C.; Cavenago, M.; Claps, G.; Muraro, A.; Murtas, F.; Pasqualotto, R.; Perelli Cippo, E.; Rebai, M.; Tardocchi, M.; Gorini, G.

    2015-04-01

    Neutron GEM-based detectors represent a new frontier of devices in neutron physics applications where a very high neutron flux must be measured such as future fusion experiments (e.g. ITER Neutral beam Injector) and spallation sources (e.g. the European Spallation source). This kind of detectors can be properly adapted to be used both as beam monitors but also as neutron diffraction detectors that could represent a valid alternative for the 3He detectors replacement. Fast neutron GEM detectors (nGEM) feature a cathode composed by one layer of polyethylene and one of aluminium (neutron scattering on hydrogen generates protons that are detected in the gas) while thermal neutron GEM detectors (bGEM) are equipped with a borated aluminium cathode (charged particles are generated through the 10B(n,α)7Li reaction). GEM detectors can be realized in large area (1 m2) and their readout can be pixelated. Three different prototypes of nGEM and one prototype of bGEM detectors of different areas and equipped with different types of readout have been built and tested. All the detectors have been used to measure the fast and thermal neutron 2D beam image at the ISIS-VESUVIO beamline. The different kinds of readout patterns (different areas of the pixels) have been compared in similar conditions. All the detectors measured a width of the beam profile consitent with the expected one. The imaging property of each detector was then tested by inserting samples of different material and shape in the beam. All the samples were correctly reconstructed and the definition of the reconstruction depends on the type of readout anode. The fast neutron beam profile reconstruction was then compared to the one obtained by diamond detectors positioned on the same beamline while the thermal neutron one was compared to the imaged obtained by cadmium-coupled x-rays films. Also efficiency and the gamma background rejection have been determined. These prototypes represent the first step towards the

  7. Precision neutron flux measurement with a neutron beam monitor

    NASA Astrophysics Data System (ADS)

    Ino, T.; Otono, H.; Mishima, K.; Yamada, T.

    2014-07-01

    Neutron beam monitors are regularly used in various neutron beam experiments to compare two or more sets of data taken in different experimental conditions. A neutron lifetime experiment at BL05, the NOP beamline, in J-PARC requires to monitor the initial neutron intensity with an precision of 0.1% to measure the neutron lifetime with the same accuracy. The performance of a thin 3He gas neutron beam monitor used for the experiment was studied to estimate the systematic uncertainties in the neutron lifetime measurement.

  8. Scintillation fiber array detector for measurement of neutron beam profile

    NASA Astrophysics Data System (ADS)

    Kim, Chong; Hong, Byungsik; Jo, Mihee; Lee, Kyong Sei; Sim, Kwang-Souk

    2009-10-01

    We built and tested a detector to measure the profile of fast-neutron beams delivered by the MC50 cyclotron at the Korea Institute of Radiological and Medical Science (KIRAMS). The core component of the detector is a 2×46 array of scintillation fibers. The light output of the scintillation fibers is transformed into a current signal by a 46-channel silicon photodiode and digitized by a current-mode signal processor. This scanning device was designed to cover a neutron beam area of 30×32 cm2. The detector was tested in a neutron beam delivered by the MC50 cyclotron at KIRAMS. We demonstrate that the detector can successfully measure the neutron beam profile at various beam currents from 10 to 20 μA. The proposed neutron beam profile detector will be useful, for example, in radiotherapy applications with neutron intensities above 107 Hz/cm2.

  9. Accelerator Based Neutron Beams for Neutron Capture Therapy

    SciTech Connect

    Yanch, Jacquelyn C.

    2003-04-11

    The DOE-funded accelerator BNCT program at the Massachusetts Institute of Technology has resulted in the only operating accelerator-based epithermal neutron beam facility capable of generating significant dose rates in the world. With five separate beamlines and two different epithermal neutron beam assemblies installed, we are currently capable of treating patients with rheumatoid arthritis in less than 15 minutes (knee joints) or 4 minutes (finger joints) or irradiating patients with shallow brain tumors to a healthy tissue dose of 12.6 Gy in 3.6 hours. The accelerator, designed by Newton scientific Incorporated, is located in dedicated laboratory space that MIT renovated specifically for this project. The Laboratory for Accelerator Beam Applications consists of an accelerator room, a control room, a shielded radiation vault, and additional laboratory space nearby. In addition to the design, construction and characterization of the tandem electrostatic accelerator, this program also resulted in other significant accomplishments. Assemblies for generating epithermal neutron beams were designed, constructed and experimentally evaluated using mixed-field dosimetry techniques. Strategies for target construction and target cooling were implemented and tested. We demonstrated that the method of submerged jet impingement using water as the coolant is capable of handling power densities of up to 6 x 10(sup 7) W/m(sup 2) with heat transfer coefficients of 10(sup 6)W/m(sup 2)-K. Experiments with the liquid metal gallium demonstrated its superiority compared with water with little effect on the neutronic properties of the epithermal beam. Monoenergetic proton beams generated using the accelerator were used to evaluate proton RBE as a function of LET and demonstrated a maximum RBE at approximately 30-40 keV/um, a finding consistent with results published by other researchers. We also developed an experimental approach to biological intercomparison of epithermal beams and

  10. Neutron Beams from Deuteron Breakup at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory

    SciTech Connect

    McMahan, M.A.; Ahle, L.; Bleuel, D.L.; Bernstein, L.; Braquest, B.R.; Cerny, J.; Heilbronn, L.H.; Jewett, C.C.; Thompson, I.; Wilson, B.

    2007-07-31

    Accelerator-based neutron sources offer many advantages, in particular tunability of the neutron beam in energy and width to match the needs of the application. Using a recently constructed neutron beam line at the 88-Inch Cyclotron at LBNL, tunable high-intensity sources of quasi-monoenergetic and broad spectrum neutrons from deuteron breakup are under development for a variety of applications.

  11. Effect of high current electron beam in a 30 MeV radio frequency linac for neutron-time-of-flight applications

    NASA Astrophysics Data System (ADS)

    Nayak, B.; Acharya, S.; Rajawat, R. K.; DasGupta, K.

    2016-01-01

    A high power pulsed radio frequency electron linac is designed by BARC, India to accelerate 30 MeV, 10 A, 10 ns beam for neutron-time-of-flight applications. It will be used as a neutron generator and will produce ˜1012-1013 n/s. It is essential to reduce the beam instability caused by space charge effect and the beam cavity interaction. In this paper, the wakefield losses in the accelerating section due to bunch of RMS (Root mean square) length 2 mm (at the gun exit) is analysed. Loss and kick factors are numerically calculated using CST wakefield solver. Both the longitudinal and transverse wake potentials are incorporated in beam dynamics code ELEGANT to find the transverse emittance growth of the beam propagating through the linac. Beam loading effect is examined by means of numerical computation carried out in ASTRA code. Beam break up start current has been estimated at the end of the linac which arises due to deflecting modes excited by the high current beam. At the end, transverse beam dynamics of such high current beam has been analysed.

  12. Epithermal neutron beams from the 7 Li(p,n) reaction near the threshold for neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Porras, I.; Praena, J.; Arias de Saavedra, F.; Pedrosa, M.; Esquinas, P.; L. Jiménez-Bonilla, P.

    2016-11-01

    Two applications for neutron capture therapy of epithermal neutron beams calculated from the 7Li ( p , n reaction are discussed. In particular, i) for a proton beam of 1920 keV of a 30 mA, a neutron beam of adequate features for BNCT is found at an angle of 80° from the forward direction; and ii) for a proton beam of 1910 keV, a neutron beam is obtained at the forward direction suitable for performing radiobiology experiments for the determination of the biological weighting factors of the fast dose component in neutron capture therapy.

  13. Neutron micro-beam design simulation by Monte Carlo

    NASA Astrophysics Data System (ADS)

    Pazirandeh, Ali; Taheri, Ali

    2007-09-01

    Over the last two decades neutron micro-beam has increasingly been developing in view of various applications in molecular activation analysis, micro-radiography in space and aviation and in radiation induced bystander effects in bio-cells. In this paper the structure and simulation of a neutron micro-beam is presented. The collimator for micro-beam is made of a polyethylene cylinder with a small hole along the centerline of the cylinder. The hole is filled with very thin needles in triangular or rectangular arrangement. The neutron source was reactor neutrons or a spontaneous Cf-252 neutron source falling on the top side of the collimator. The outgoing thermal and epithermal neutron fluxes were calculated.

  14. Beam extraction and delivery at compact neutron sources

    NASA Astrophysics Data System (ADS)

    Mezei, F.

    2016-11-01

    The beam performance of a source of radiation is primarily characterized by its brightness, which remains constant in a conservative force field along the propagation of the beam. The neutron flux at an area with direct view to a homogenous radiation emitting moderator surface will just depend on the solid angle of beam divergence as determined by the moderator size. Recently it was found that by reducing the size of neutron moderators their brightness can be enhanced by a factor in the range of up to 3-6. In direct view of such moderators from sizable distances often required in neutron scattering applications the beam divergence will become reduced. Supermirror based neutron optical guide systems allow us to deliver neutron beam divergences independently of distance from the source. Due to the low radiation fields at compact sources such systems can be placed close to the neutron emitting moderators, a specific advantage and a new design feature. Focusing type neutron guides with phase space acceptance properly matched to the phase space to be delivered over distance can provide for beam delivery with small losses of brightness within a convenient and flexible range of beam parameters.

  15. A neutron diagnostic for high current deuterium beams

    SciTech Connect

    Rebai, M.; Perelli Cippo, E.; Cavenago, M.; Dalla Palma, M.; Pasqualotto, R.; Tollin, M.; Croci, G.; Gervasini, G.; Ghezzi, F.; Grosso, G.; Tardocchi, M.; Murtas, F.; Gorini, G.

    2012-02-15

    A neutron diagnostic for high current deuterium beams is proposed for installation on the spectral shear interferometry for direct electric field reconstruction (SPIDER, Source for Production of Ion of Deuterium Extracted from RF plasma) test beam facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission on the beam dump surface by placing a detector in close contact, right behind the dump. CNESM uses gas electron multiplier detectors equipped with a cathode that also serves as neutron-proton converter foil. The cathode is made of a thin polythene film and an aluminium film; it is designed for detection of neutrons of energy >2.2 MeV with an incidence angle < 45 deg. CNESM was designed on the basis of simulations of the different steps from the deuteron beam interaction with the beam dump to the neutron detection in the nGEM. Neutron scattering was simulated with the MCNPX code. CNESM on SPIDER is a first step towards the application of this diagnostic technique to the MITICA beam test facility, where it will be used to resolve the horizontal profile of the beam intensity.

  16. Clinical assessment of 252Californium neutron intracavitary brachytherapy using a two-channel Y applicator combined with external beam radiotherapy for endometrial cancer

    PubMed Central

    Zhou, Qian; Cheng Tang; Zhao, Ke-Wei; Xiong, Yan-Li; Chen, Shu; Xu, Wen-Jing; Lei, Xin

    2016-01-01

    OBJECTIVE: The aim of this study was to determine the efficacy of 252Californium neutron intracavitary brachytherapy using a two-channel Y applicator combined with external beam radiotherapy for the treatment of endometrial cancer. METHODS: Thirty-one patients with stage I–III endometrial cancer were recruited for this study. The stage I patients received only 252Californium neutron intracavitary brachytherapy with a two-channel applicator. The stage II and III patients received both 252Californium neutron intracavitary brachytherapy using a two-channel applicator and parallel-opposed whole pelvic radiotherapy. RESULTS: The five-year local control rate was 80.6% (25/31), the overall survival rate was 51.6% (16/31), and the disease-free survival rate was 54.8% (17/31). The incidence of serious late complications was 12.9% (4/31). CONCLUSIONS: 252Californium neutron intracavitary brachytherapy using a two-channel applicator combined with external beam radiotherapy was effective for treating endometrial cancer and the incidence of serious late complications related to this combination was within an acceptable range. PMID:26872078

  17. Neutron measurements from beam-target reactions at the ELISE neutral beam test facility

    SciTech Connect

    Xufei, X. Fan, T.; Nocente, M.; Gorini, G.; Bonomo, F.; Franzen, P.; Fröschle, M.; Grosso, G.; Tardocchi, M.; Grünauer, F.; Pasqualotto, R.

    2014-11-15

    Measurements of 2.5 MeV neutron emission from beam-target reactions performed at the ELISE neutral beam test facility are presented in this paper. The measurements are used to study the penetration of a deuterium beam in a copper dump, based on the observation of the time evolution of the neutron counting rate from beam-target reactions with a liquid scintillation detector. A calculation based on a local mixing model of deuterium deposition in the target up to a concentration of 20% at saturation is used to evaluate the expected neutron yield for comparison with data. The results are of relevance to understand neutron emission associated to beam penetration in a solid target, with applications to diagnostic systems for the SPIDER and MITICA Neutral Beam Injection prototypes.

  18. Neutron beam imaging at neutron spectrometers at Dhruva

    SciTech Connect

    Desai, Shraddha S.; Rao, Mala N.

    2012-06-05

    A low efficiency, 2-Dimensional Position Sensitive Neutron Detector based on delay line position encoding is developed. It is designed to handle beam flux of 10{sup 6}-10{sup 7} n/cm{sup 2}/s and for monitoring intensity profiles of neutron beams. The present detector can be mounted in transmission mode, as the hardware allows maximum neutron transmission in sensitive region. Position resolution of 1.2 mm in X and Y directions, is obtained. Online monitoring of beam images and intensity profile of various neutron scattering spectrometers at Dhruva are presented. It shows better dynamic range of intensity over commercial neutron camera and is also time effective over the traditionally used photographic method.

  19. Neutron sources and applications

    SciTech Connect

    Price, D.L.; Rush, J.J.

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

  20. New analytical approach for neutron beam-hardening correction.

    PubMed

    Hachouf, N; Kharfi, F; Hachouf, M; Boucenna, A

    2016-01-01

    In neutron imaging, the beam-hardening effect has a significant effect on quantitative and qualitative image interpretation. This study aims to propose a linearization method for beam-hardening correction. The proposed method is based on a new analytical approach establishing the attenuation coefficient as a function of neutron energy. Spectrum energy shift due to beam hardening is studied on the basis of Monte Carlo N-Particle (MCNP) simulated data and the analytical data. Good agreement between MCNP and analytical values has been found. Indeed, the beam-hardening effect is well supported in the proposed method. A correction procedure is developed to correct the errors of beam-hardening effect in neutron transmission, and therefore for projection data correction. The effectiveness of this procedure is determined by its application in correcting reconstructed images.

  1. New analytical approach for neutron beam-hardening correction.

    PubMed

    Hachouf, N; Kharfi, F; Hachouf, M; Boucenna, A

    2016-01-01

    In neutron imaging, the beam-hardening effect has a significant effect on quantitative and qualitative image interpretation. This study aims to propose a linearization method for beam-hardening correction. The proposed method is based on a new analytical approach establishing the attenuation coefficient as a function of neutron energy. Spectrum energy shift due to beam hardening is studied on the basis of Monte Carlo N-Particle (MCNP) simulated data and the analytical data. Good agreement between MCNP and analytical values has been found. Indeed, the beam-hardening effect is well supported in the proposed method. A correction procedure is developed to correct the errors of beam-hardening effect in neutron transmission, and therefore for projection data correction. The effectiveness of this procedure is determined by its application in correcting reconstructed images. PMID:26609685

  2. A multitask neutron beam line for spallation neutron sources

    NASA Astrophysics Data System (ADS)

    Pietropaolo, A.; Festa, G.; Grazzi, F.; Barzagli, E.; Scherillo, A.; Schooneveld, E. M.; Civita, F.

    2011-08-01

    Here we present a new concept for a time-of-flight neutron scattering instrument allowing for simultaneous application of three different techniques: time-of-flight neutron diffraction, neutron resonance capture analysis and Bragg edge transmission analysis. The instrument can provide average resolution neutron radiography too. The potential of the proposed concept was explored by implementing the necessary equipment on INES (Italian Neutron Experimental Station) at the ISIS spallation neutron source (UK). The results obtained show the effectiveness of the proposed instrument to acquire relevant quantitative information in a non-invasive way on a historical metallurgical sample, namely a Japanese hand guard (tsuba). The aforementioned neutron techniques simultaneously exploited the extended neutron energy range available from 10 meV to 1 keV. This allowed a fully satisfactory characterization of the sample in terms of metal components and their combination in different phases, and forging and assembling methods.

  3. Fast ion beam chopping system for neutron generators

    NASA Astrophysics Data System (ADS)

    Hahto, S. K.; Hahto, S. T.; Leung, K. N.; Reijonen, J.; Miller, T. G.; Van Staagen, P. K.

    2005-02-01

    Fast deuterium (D+) and tritium (T+) ion beam pulses are needed in some neutron-based imaging systems. A compact, integrated fast ion beam extraction and chopping system has been developed and tested at the Lawrence Berkeley National Laboratory for these applications, and beam pulses with 15ns full width at half maximum have been achieved. Computer simulations together with experimental tests indicate that even faster pulses are achievable by shortening the chopper voltage rise time. This chopper arrangement will be implemented in a coaxial neutron generator, in which a small point-like neutron source is created by multiple 120keV D+ ion beams hitting a titanium target at the center of the source.

  4. Fast ion beam chopping system for neutron generators

    SciTech Connect

    Hahto, S.K.; Hahto, S.T.; Leung, K.N.; Reijonen, J.; Miller, T.G.; Van Staagen, P.K.

    2005-02-01

    Fast deuterium (D{sup +}) and tritium (T{sup +}) ion beam pulses are needed in some neutron-based imaging systems. A compact, integrated fast ion beam extraction and chopping system has been developed and tested at the Lawrence Berkeley National Laboratory for these applications, and beam pulses with 15 ns full width at half maximum have been achieved. Computer simulations together with experimental tests indicate that even faster pulses are achievable by shortening the chopper voltage rise time. This chopper arrangement will be implemented in a coaxial neutron generator, in which a small point-like neutron source is created by multiple 120 keV D{sup +} ion beams hitting a titanium target at the center of the source.

  5. Neutron transport study of a beam port based dynamic neutron radiography facility

    NASA Astrophysics Data System (ADS)

    Khaial, Anas M.

    Neutron radiography has the ability to differentiate between gas and liquid in two-phase flow due both to the density difference and the high neutron scattering probability of hydrogen. Previous studies have used dynamic neutron radiography -- in both real-time and high-speed -- for air-water, steam-water and gas-liquid metal two-phase flow measurements. Radiography with thermal neutrons is straightforward and efficient as thermal neutrons are easier to detect with relatively higher efficiency and can be easily extracted from nuclear reactor beam ports. The quality of images obtained using neutron radiography and the imaging speed depend on the neutron beam intensity at the imaging plane. A high quality neutron beam, with thermal neutron intensity greater than 3.0x 10 6 n/cm2-s and a collimation ratio greater than 100 at the imaging plane, is required for effective dynamic neutron radiography up to 2000 frames per second. The primary objectives of this work are: (1) to optimize a neutron radiography facility for dynamic neutron radiography applications and (2) to investigate a new technique for three-dimensional neutron radiography using information obtained from neutron scattering. In this work, neutron transport analysis and experimental validation of a dynamic neutron radiography facility is studied with consideration of real-time and high-speed neutron radiography requirements. A beam port based dynamic neutron radiography facility, for a target thermal neutron flux of 1.0x107 n/cm2-s, has been analyzed, constructed and experimentally verified at the McMaster Nuclear Reactor. The neutron source strength at the beam tube entrance is evaluated experimentally by measuring the thermal and fast neutron fluxes using copper activation flux-mapping technique. The development of different facility components, such as beam tube liner, gamma ray filter, beam shutter and biological shield, is achieved analytically using neutron attenuation and divergence theories. Monte

  6. Compact neutron generator developement and applications

    SciTech Connect

    Leung, Ka-Ngo; Reijonen, Jani; Gicquel, Frederic; Hahto, Sami; Lou, Tak-Pui

    2004-01-18

    The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory has been engaging in the development of high yield compact neutron generators for the last ten years. Because neutrons in these generators are formed by using either D-D, T-T or D-T fusion reaction, one can produce either mono-energetic (2.4 MeV or 14 MeV) or white neutrons. All the neutron generators being developed by our group utilize 13.5 MHz RF induction discharge to produce a pure deuterium or a mixture of deuterium-tritium plasma. As a result, ion beams with high current density and almost pure atomic ions can be extracted from the plasma source. The ion beams are accelerated to {approx}100 keV and neutrons are produced when the beams impinge on a titanium target. Neutron generators with different configurations and sizes have been designed and tested at LBNL. Their applications include neutron activation analysis, oil-well logging, boron neutron capture therapy, brachytherapy, cargo and luggage screening. A novel small point neutron source has recently been developed for radiography application. The source size can be 2 mm or less, making it possible to examine objects with sharper images. The performance of these neutron generators will be described in this paper.

  7. Beam Characterization at the Neutron Radiography Facility

    SciTech Connect

    Sarah Morgan; Jeffrey King

    2013-01-01

    The quality of a neutron imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam’s effective length-to-diameter ratio, neutron flux profile, energy spectrum, image quality, and beam divergence, is vital for producing quality radiographic images. This project characterized the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam’s effective length-to-diameter ratio and image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. Improvement of the existing NRAD MCNP beamline model includes validation of the model’s energy spectrum and the development of enhanced image simulation methods. The image simulation methods predict the radiographic image of an object based on the foil reaction rate data obtained by placing a model of the object in front of the image plane in an MCNP beamline model.

  8. A white beam neutron spin splitter

    SciTech Connect

    Krist, T.; Klose, F.; Felcher, G.P.

    1997-07-23

    The polarization of a narrow, highly collimated polychromatic neutron beam is tested by a neutron spin splitter that permits the simultaneous measurement of both spin states. The device consists of a Si-Co{sub 0.11} Fe{sub 0.89} supermirror, which totally reflects one spin state up to a momentum transfer q=0.04 {angstrom}{sup -1}, whilst transmits neutrons of the opposite spin state. The supermirror is sandwitched between two thick silicon wafers and is magnetically saturated by a magnetic field of 400 Oe parallel to its surface. The neutron beam enters through the edge of one of the two silicon wavers, its spin components are split by the supermirror and exit from the opposite edges of the two silicon wafers and are recorded at different channels of a position-sensitive detector. The device is shown to have excellent efficiency over a broad range of wavelengths.

  9. Optimal Neutron Source & Beam Shaping Assembly for Boron Neutron Capture Therapy

    SciTech Connect

    J. Vujic; E. Greenspan; W.E. Kastenber; Y. Karni; D. Regev; J.M. Verbeke, K.N. Leung; D. Chivers; S. Guess; L. Kim; W. Waldron; Y. Zhu

    2003-04-30

    There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

  10. Neutron tomography developments and applications.

    PubMed

    Richards, W J; Gibbons, M R; Shields, K C

    2004-10-01

    Neutron radiography has been in use as a nondestructive testing technique for the past 50 years. The neutrons' unique ability to image certain elements and isotopes that are either completely undetectable or poorly detected by other NDI methods makes neutron radiography an important tool for the NDI community. Neutron radiography like other imaging techniques takes a number of different forms (i.e., film, radioscopic, transfer methods, tomography, etc.) This paper will describe the neutron tomography system developed at the University of California, Davis McClellan Nuclear Radiation Center (UC Davis/MNRC), and the applications for both research and commercial uses. The neutron radiography system at the UC Davis/MNRC has been under development for 4 years. The initial system was developed to find very low concentrations of hydrogen (i.e., <200 ppm). In order to achieve these low detection levels, it was necessary to perform both pre- and post-processing of the tomographs. The pre-processing steps include corrections for spatial resolution and random noise effects. Images are corrected for systematic noise errors and beam hardening. From these data the attenuation coefficient is calculated. The post-processing steps include alignment of the collected images, determining the center of mass, and, finally, using the filtered back-projection routine from the Donner Algorithms Library to obtain the final images. Since its initial development, the tomography system has been used very successfully to find low levels of hydrogen in a metal matrix. Further uses of the system have been to verify the exact placement, in three dimensions, of "O-rings" in large metal valve bodies, and to map the location and extent of veins in porous and high-density rocks of various different kinds. These examples show that neutron tomography is becoming a needed inspection technique for the 21st century. PMID:15246398

  11. Design, construction and characterization of a new neutron beam for neutron radiography at the Tehran Research Reactor

    NASA Astrophysics Data System (ADS)

    Choopan Dastjerdi, M. H.; Khalafi, H.; Kasesaz, Y.; Mirvakili, S. M.; Emami, J.; Ghods, H.; Ezzati, A.

    2016-05-01

    To obtain a thermal neutron beam for neutron radiography applications, a neutron collimator has been designed and implemented at the Tehran Research Reactor (TRR). TRR is a 5 MW open pool light water moderated reactor with seven beam tubes. The neutron collimator is implemented in the E beam tube of the TRR. The design of the neutron collimator was performed using MCNPX Monte Carlo code. In this work, polycrystalline bismuth and graphite have been used as a gamma filter and an illuminator, respectively. The L/D parameter of the facility was chosen in the range of 150-250. The thermal neutron flux at the image plane can be varied from 2.26×106 to 6.5×106 n cm-2 s-1. Characterization of the beam was performed by ASTM standard IQI and foil activation technique to determine the quality of neutron beam. The results show that the obtained neutron beam has a good quality for neutron radiography applications.

  12. Experiments with neutron-rich isomeric beams

    SciTech Connect

    Rykaczewski, K. |; Grzywacz, R. |; Lewitowicz, M.; Pfuetzner, M.; Grawe, H.

    1998-01-01

    A review of experimental results obtained on microsecond-isomeric states in neutron-rich nuclei produced in fragmentation reactions and studied with SISSI-Alpha-LISE3 spectrometer system at GANIL Caen is given. The perspectives of experiments based on secondary reactions with isomeric beams are presented.

  13. How to polarise all neutrons in one beam: a high performance polariser and neutron transport system

    NASA Astrophysics Data System (ADS)

    Rodriguez, D. Martin; Bentley, P. M.; Pappas, C.

    2016-09-01

    Polarised neutron beams are used in disciplines as diverse as magnetism,soft matter or biology. However, most of these applications often suffer from low flux also because the existing neutron polarising methods imply the filtering of one of the spin states, with a transmission of 50% at maximum. With the purpose of using all neutrons that are usually discarded, we propose a system that splits them according to their polarisation, flips them to match the spin direction, and then focuses them at the sample. Monte Carlo (MC) simulations show that this is achievable over a wide wavelength range and with an outstanding performance at the price of a more divergent neutron beam at the sample position.

  14. Assessment of ideal neutron beams for neutron capture therapy.

    PubMed

    Storr, G J

    1992-09-01

    The discrete-ordinates transport computer code DORT has been used to develop a two-dimensional cylindrical phantom model for use as a tool to assess beam design and dose distributions for boron neutron capture therapy. The model uses an S8 approximation for angular fluxes and a P3 Legendre approximation for scattering cross sections. A one-dimensional discrete-ordinates model utilizing the computer code ANISN was used to validate the energy-group structure used in the two-dimensional calculations. In the two-dimensional model the effects of varying basic parameters such as aperture width, neutron source energy, and tissue composition have been studied. Identical results were obtained when comparing narrow beam calculations to fine-mesh higher-order Sn treatments (up to S32), and with P5 cross sections. It is shown that, when the correct assessment volume is used, narrow beams will give little or no advantage for therapy even with an optimum-energy ideal neutron beam.

  15. High Intensity Neutron Beams for Small Samples

    NASA Astrophysics Data System (ADS)

    Böni, Peter

    2014-04-01

    As novel materials of excellent homogeneity can often only be grown in small quantities it is important to optimize the transport of neutrons from the moderator to the sample while keeping the background low. Using elliptically or parabolically tapered guides the losses can be strongly reduced such that 50% - 90% of the useful neutrons arrive at the sample. If not properly designed, however, the divergence at the sample becomes inhomogeneous. In contrast, pairs of nested Kirkpatrick-Baez mirrors in Montel geometry yield well focused beams with a compact phase space. The mirrors extract only the useful neutrons from the moderator and effectively interrupt the line of sight leading to a very low background. As the focal distances are typically several meters, the extraction of the neutrons and the installation of bulky sample environment is facilitated.

  16. Progress on the realization of a new GEM based neutron diagnostic concept for high flux neutron beams

    SciTech Connect

    Croci, G.; Tardocchi, M.; Rebai, M.; Cippo, E. Perelli; Gorini, G.; Cazzaniga, C.; Palma, M. Dalla; Pasqualotto, R.; Tollin, M.; Grosso, G.; Muraro, A.; Murtas, F.; Claps, G.; Cavenago, M.

    2014-08-21

    Fusion reactors will need high flux neutron detectors to diagnose the deuterium-deuterium and deuterium-tritium. A candidate detection technique is the Gas Electron Multiplier (GEM). New GEM based detectors are being developed for application to a neutral deuterium beam test facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission due to interaction of the deuterium beam with the deuterons implanted in the beam dump surface. This is done by placing a detector in close contact, right behind the dump. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron-proton converter foil. After the realization and test of several small area prototypes, a full size prototype has been realized and tested with laboratory sources. Test on neutron beams are foreseen for the next months.

  17. Progress on the realization of a new GEM based neutron diagnostic concept for high flux neutron beams

    NASA Astrophysics Data System (ADS)

    Croci, G.; Rebai, M.; Cazzaniga, C.; Palma, M. Dalla; Grosso, G.; Muraro, A.; Murtas, F.; Claps, G.; Pasqualotto, R.; Cippo, E. Perelli; Tardocchi, M.; Tollin, M.; Cavenago, M.; Gorini, G.

    2014-08-01

    Fusion reactors will need high flux neutron detectors to diagnose the deuterium-deuterium and deuterium-tritium. A candidate detection technique is the Gas Electron Multiplier (GEM). New GEM based detectors are being developed for application to a neutral deuterium beam test facility. The proposed detection system is called Close-contact Neutron Emission Surface Mapping (CNESM). The diagnostic aims at providing the map of the neutron emission due to interaction of the deuterium beam with the deuterons implanted in the beam dump surface. This is done by placing a detector in close contact, right behind the dump. CNESM uses nGEM detectors, i.e. GEM detectors equipped with a cathode that also serves as neutron-proton converter foil. After the realization and test of several small area prototypes, a full size prototype has been realized and tested with laboratory sources. Test on neutron beams are foreseen for the next months.

  18. Neutron Flux Characterization of the Cold Beam PGAA-NIPS Facility at the Budapest Research Reactor

    NASA Astrophysics Data System (ADS)

    Belgya, T.; Kis, Z.; Szentmiklósi, L.

    2014-05-01

    Reliable flux characterization is essential for facilities using neutron beams. Hence, the NIPS station at the Budapest Research Reactor has recently been equipped with neutron-tomographic equipment. The beam can also be characterized by means of a large surface wire chamber and application of the time-of-flight method. The energy distribution was measured at three horizontal positions with the surface wire chamber in pinhole geometry, while the spatial inhomogeneity was determined by means of our new neutron-tomographic equipment.

  19. Fast fall-time ion beam in neutron generators

    SciTech Connect

    Ji, Q.; Kwan, J.; Regis, M.; Wu, Y.; Wilde, S.B.; Wallig, J.

    2008-08-10

    Ion beam with a fast fall time is useful in building neutron generators for the application of detecting hidden, gamma-shielded SNM using differential die-away (DDA) technique. Typically a fall time of less than 1 {micro}s can't be achieved by just turning off the power to the ion source due to the slow decay of plasma density (partly determined by the fall time of the RF power in the circuit). In this paper, we discuss the method of using an array of mini-apertures (instead of one large aperture beam) such that gating the beamlets can be done with low voltage and a small gap. This geometry minimizes the problem of voltage breakdown as well as reducing the time of flight to produce fast gating. We have designed and fabricated an array of 16 apertures (4 x 4) for a beam extraction experiment. Using a gating voltage of 1400 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is less than 1 {micro}s at various beam energies ranging between 400 eV to 800 eV. Usually merging an array of beamlets suffers the loss of beam brightness, i.e., emittance growth, but that is not an important issue for neutron source applications.

  20. GEANT4 used for neutron beam design of a neutron imaging facility at TRIGA reactor in Morocco

    NASA Astrophysics Data System (ADS)

    Ouardi, A.; Machmach, A.; Alami, R.; Bensitel, A.; Hommada, A.

    2011-09-01

    Neutron imaging has a broad scope of applications and has played a pivotal role in visualizing and quantifying hydrogenous masses in metallic matrices. The field continues to expand into new applications with the installation of new neutron imaging facilities. In this scope, a neutron imaging facility for computed tomography and real-time neutron radiography is currently being developed around 2.0MW TRIGA MARK-II reactor at Maamora Nuclear Research Center in Morocco (Reuscher et al., 1990 [1]; de Menezes et al., 2003 [2]; Deinert et al., 2005 [3]). The neutron imaging facility consists of neutron collimator, real-time neutron imaging system and imaging process systems. In order to reduce the gamma-ray content in the neutron beam, the tangential channel was selected. For power of 250 kW, the corresponding thermal neutron flux measured at the inlet of the tangential channel is around 3×10 11 ncm 2/s. This facility will be based on a conical neutron collimator with two circular diaphragms with diameters of 4 and 2 cm corresponding to L/D-ratio of 165 and 325, respectively. These diaphragms' sizes allow reaching a compromise between good flux and efficient L/D-ratio. Convergent-divergent collimator geometry has been adopted. The beam line consists of a gamma filter, fast neutrons filter, neutron moderator, neutron and gamma shutters, biological shielding around the collimator and several stages of neutron collimator. Monte Carlo calculations by a fully 3D numerical code GEANT4 were used to design the neutron beam line ( http://www.info.cern.ch/asd/geant4/geant4.html[4]). To enhance the neutron thermal beam in terms of quality, several materials, mainly bismuth (Bi) and sapphire (Al 2O 3) were examined as gamma and neutron filters respectively. The GEANT4 simulations showed that the gamma and epithermal and fast neutron could be filtered using the bismuth (Bi) and sapphire (Al 2O 3) filters, respectively. To get a good cadmium ratio, GEANT 4 simulations were used to

  1. Neutron tube design study for boron neutron capture therapy application

    SciTech Connect

    Verbeke, J.M.; Lee, Y.; Leung, K.N.; Vujic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1999-05-06

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator application. By using a 5-cm-diameter RF-driven multicusp source H{sup +} yields over 95% have been achieved. These experimental findings will enable one to develop compact neutron generators based on the D-D or D-T fusion reactions. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without external pumping. Recent moderator design simulation studies have shown that 14 MeV neutrons could be moderated to therapeutically useful energy ranges for boron neutron capture therapy (BNCT). The dose near the center of the brain with optimized moderators is about 65% higher than the dose obtained from a typical neutron spectrum produced by the Brookhaven Medical Research Reactor (BMRR), and is comparable to the dose obtained by other accelerator-based neutron sources. With a 120 keV and 1 A deuteron beam, a treatment time of {approx}35 minutes is estimated for BNCT.

  2. Optimization study for an epithermal neutron beam for boron neutron capture therapy at the University of Virginia Research Reactor

    SciTech Connect

    Burns, T.D. Jr.

    1995-05-01

    The non-surgical brain cancer treatment modality, Boron Neutron Capture Therapy (BNCT), requires the use of an epithermal neutron beam. This purpose of this thesis was to design an epithermal neutron beam at the University of Virginia Research Reactor (UVAR) suitable for BNCT applications. A suitable epithermal neutron beam for BNCT must have minimal fast neutron and gamma radiation contamination, and yet retain an appreciable intensity. The low power of the UVAR core makes reaching a balance between beam quality and intensity a very challenging design endeavor. The MCNP monte carlo neutron transport code was used to develop an equivalent core radiation source, and to perform the subsequent neutron transport calculations necessary for beam model analysis and development. The code accuracy was validated by benchmarking output against experimental criticality measurements. An epithermal beam was designed for the UVAR, with performance characteristics comparable to beams at facilities with cores of higher power. The epithermal neutron intensity of this beam is 2.2 {times} 10{sup 8} n/cm{sup 2} {center_dot} s. The fast neutron and gamma radiation KERMA factors are 10 {times} 10{sup {minus}11}cGy{center_dot}cm{sup 2}/n{sub epi} and 20 {times} 10{sup {minus}11} cGy{center_dot}cm{sup 2}/n{sub epi}, respectively, and the current-to-flux ratio is 0.85. This thesis has shown that the UVAR has the capability to provide BNCT treatments, however the performance characteristics of the final beam of this study were limited by the low core power.

  3. Neutron imaging experiments at E-12 beam-line of CIRUS

    SciTech Connect

    Agrawal, Ashish; Kashyap, Yogesh; Shukla, Mayank; Sarkar, P. S.; Sinha, Amar

    2013-02-05

    Neutron imaging beam-line at E-12 beam port of CIRUS reactor India has been developed to implement Neutron tomography, phase contrast imaging and dynamic imaging techniques for various applications. Several experiments on these techniques have been carried out successfully. Neutron radiography and tomography has been used to study blisters formation in pressure tube along with many other applications. Similarly phase contrast imaging has been used to study its feasibility for better contrast in radiographic images. Dynamic imaging has been applied to study the melting of pure and impure lead under heat. In this paper we report the details of various experiments performed at this beam-line.

  4. Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source

    SciTech Connect

    C.L. Ellison and J. Fuchs

    2010-09-23

    High-flux neutrons for imaging and materials analysis applications have typically been provided by accelerator- and reactor-based neutron sources. A novel approach is to use ultraintense (>1018W/cm2) lasers to generate picosecond, collimated neutrons from a dual target configuration. In this article, the production capabilities of present and upcoming laser facilities are estimated while independently maximizing neutron yields and minimizing beam divergence. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. Tailoring of the incident distribution via laser parameters and microlens focusing modifies the emerging neutrons. Projected neutron yields and distributions are compared to conventional sources, yielding comparable on-target fluxes per discharge, shorter time resolution, larger neutron energies and greater collimation.

  5. Time-of-flight four-beam neutron reflectometer REFLEX at the high-flux pulsed reactor IBR-2: some polarized neutron reflectometry applications

    NASA Astrophysics Data System (ADS)

    Aksenov, V. L.; Korneev, Daniel A.; Chernenko, L. P.

    1992-11-01

    This paper discusses the new neutron reflectometer being built on the high flux pulsed reactor IBR-2 in Dubna. A new method is suggested for measuring and interpretation of data in the study of inhomogeneous (noncollinear) magnetization depth profile in thin films. It is important to take into account the surface roughness in the interpretation of the data from the measurements of the magnetic field penetration depth in superconductors.

  6. Beamed neutron emission driven by laser accelerated light ions

    NASA Astrophysics Data System (ADS)

    Kar, S.; Green, A.; Ahmed, H.; Alejo, A.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; Mirfayzi, S. R.; McKenna, P.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.

    2016-05-01

    Highly anisotropic, beam-like neutron emission with peak flux of the order of 109 n/sr was obtained from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by a sub-petawatt laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of ˜ 70^\\circ , with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher-catcher materials indicates the dominant reactions being d(p, n+p)1H and d(d,n)3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons’ spatial and spectral profiles is most likely related to the directionality and high energy of the projectile ions.

  7. OPTIMIZATION OF THE EPITHERMAL NEUTRON BEAM FOR BORON NEUTRON CAPTURE THERAPY AT THE BROOKHAVEN MEDICAL RESEARCH REACTOR.

    SciTech Connect

    HU,J.P.; RORER,D.C.; RECINIELLO,R.N.; HOLDEN,N.E.

    2002-08-18

    Clinical trials of Boron Neutron Capture Therapy for patients with malignant brain tumor had been carried out for half a decade, using an epithermal neutron beam at the Brookhaven's Medical Reactor. The decision to permanently close this reactor in 2000 cut short the efforts to implement a new conceptual design to optimize this beam in preparation for use with possible new protocols. Details of the conceptual design to produce a higher intensity, more forward-directed neutron beam with less contamination from gamma rays, fast and thermal neutrons are presented here for their potential applicability to other reactor facilities. Monte Carlo calculations were used to predict the flux and absorbed dose produced by the proposed design. The results were benchmarked by the dose rate and flux measurements taken at the facility then in use.

  8. Improvement of the cold neutron beam line (CN-3) in KUR for neutron optical device development

    NASA Astrophysics Data System (ADS)

    Kawabata, Yuji; Hino, Masahiro; Tasaki, Seiji; Ebisawa, Toru; Maruyama, Ryuji; Horie, Takashi

    2002-01-01

    The cold neutron beam line CN-3 in Kyoto University Reactor (KUR) is being renewed for dedicating to the development of neutron optical devices. CN-3 has a supermirror guide tube with the cross-section of 20 mm (width)× 90 mm (height), and the wide-band neutron spectrum is available. New beam lines are prepared for both time-of-flight (TOF) and monochromatic experiments including a neutron reflectivity measurement. It has a polarized neutron option with a very low magnetic field to cope with polarized neutron devices. In particular, the TOF mode will be used for developing devices, which are suitable for pulsed neutron sources. Cold neutron radiography is also available within a space of 1 m×0.8 m. A neutron imaging plate system is prepared as the neutron imaging detection.

  9. Neutron beam characterization measurements at the Manuel Lujan Jr. neutron scattering center

    SciTech Connect

    Mocko, Michal; Muhrer, Guenter; Daemen, Luke L; Kelsey, Charles T; Duran, Michael A; Tovesson, Fredrik K

    2010-01-01

    We have measured the neutron beam characteristics of neutron moderators at the Manuel Lujan Jr. Neutron Scattering Center at LANSCE. The absolute thermal neutron flux, energy spectra and time emission spectra were measured for the high resolution and high intensity decoupled water, partially coupled liquid hydrogen and partially coupled water moderators. The results of our experimental study will provide an insight into aging of different target-moderator-reflector-shield components as well as new experimental data for benchmarking of neutron transport codes.

  10. Development and construction of a neutron beam line for accelerator-based boron neutron capture synovectomy.

    PubMed

    Gierga, D P; Yanch, J C; Shefer, R E

    2000-01-01

    A potential application of the 10B(n, alpha)7Li nuclear reaction for the treatment of rheumatoid arthritis, termed Boron Neutron Capture Synovectomy (BNCS), is under investigation. In an arthritic joint, the synovial lining becomes inflamed and is a source of great pain and discomfort for the afflicted patient. The goal of BNCS is to ablate the synovium, thereby eliminating the symptoms of the arthritis. A BNCS treatment would consist of an intra-articular injection of boron followed by neutron irradiation of the joint. Monte Carlo radiation transport calculations have been used to develop an accelerator-based epithermal neutron beam line for BNCS treatments. The model includes a moderator/reflector assembly, neutron producing target, target cooling system, and arthritic joint phantom. Single and parallel opposed beam irradiations have been modeled for the human knee, human finger, and rabbit knee joints. Additional reflectors, placed to the side and back of the joint, have been added to the model and have been shown to improve treatment times and skin doses by about a factor of 2. Several neutron-producing charged particle reactions have been examined for BNCS, including the 9Be(p,n) reaction at proton energies of 4 and 3.7 MeV, the 9Be(d,n) reaction at deuteron energies of 1.5 and 2.6 MeV, and the 7Li(p,n) reaction at a proton energy of 2.5 MeV. For an accelerator beam current of 1 mA and synovial boron uptake of 1000 ppm, the time to deliver a therapy dose of 10,000 RBEcGy ranges from 3 to 48 min, depending on the treated joint and the neutron producing charged particle reaction. The whole-body effective dose that a human would incur during a knee treatment has been estimated to be 3.6 rem or 0.75 rem, for 1000 ppm or 19,000 ppm synovial boron uptake, respectively, although the shielding configuration has not yet been optimized. The Monte Carlo design process culminated in the construction, installation, and testing of a dedicated BNCS beam line on the high

  11. Three-port beam splitter for slow neutrons using holographic nanoparticle-polymer composite diffraction gratings

    SciTech Connect

    Klepp, J.; Fally, M.; Tomita, Y.; Pruner, C.; Kohlbrecher, J.

    2012-10-08

    Diffraction of slow neutrons by nanoparticle-polymer composite gratings has been observed. By carefully choosing grating parameters such as grating thickness and spacing, a three-port beam splitter operation for slow neutrons - splitting the incident neutron intensity equally into the {+-}1st and the 0th diffraction orders - has been realized. As a possible application, a Zernike three-path interferometer is briefly discussed.

  12. Characterization of the high-energy neutron beam of the PRISMA beamline using a diamond detector

    NASA Astrophysics Data System (ADS)

    Cazzaniga, C.; Frost, C. D.; Minniti, T.; Schooneveld, E.; Perelli Cippo, E.; Tardocchi, M.; Rebai, M.; Gorini, G.

    2016-07-01

    The high-energy neutron component (En > 10 MeV) of the neutron spectrum of PRISMA, a beam-line at the ISIS spallation source, has been characterized for the first time. Neutron measurements using a Single-crystal Diamond Detector at a short-pulse source are obtained by a combination of pulse height and time of flight analysis. An XY scan provides a 2D map of the high-energy neutron beam which has a diameter of about 40 mm. The high neutron flux, that has been found to be (3.8 ± 0.7) · 105 cm‑2s‑1 for En > 10 MeV in the centre, opens up for a possible application of the beam-line as a high-energy neutron irradiation position. Results are of interest for the development of the ChipIR beam-line, which will feature an atmospheric-like neutron spectrum for chip irradiation experiment. Furthermore, these results demonstrate that diamond detectors can be used at spallation sources to investigate the transport of high-energy neutrons down instruments which is of interest in general to designers as high-energy neutrons are a source of background in thermal beamlines.

  13. Characterization of the high-energy neutron beam of the PRISMA beamline using a diamond detector

    NASA Astrophysics Data System (ADS)

    Cazzaniga, C.; Frost, C. D.; Minniti, T.; Schooneveld, E.; Perelli Cippo, E.; Tardocchi, M.; Rebai, M.; Gorini, G.

    2016-07-01

    The high-energy neutron component (En > 10 MeV) of the neutron spectrum of PRISMA, a beam-line at the ISIS spallation source, has been characterized for the first time. Neutron measurements using a Single-crystal Diamond Detector at a short-pulse source are obtained by a combination of pulse height and time of flight analysis. An XY scan provides a 2D map of the high-energy neutron beam which has a diameter of about 40 mm. The high neutron flux, that has been found to be (3.8 ± 0.7) · 105 cm-2s-1 for En > 10 MeV in the centre, opens up for a possible application of the beam-line as a high-energy neutron irradiation position. Results are of interest for the development of the ChipIR beam-line, which will feature an atmospheric-like neutron spectrum for chip irradiation experiment. Furthermore, these results demonstrate that diamond detectors can be used at spallation sources to investigate the transport of high-energy neutrons down instruments which is of interest in general to designers as high-energy neutrons are a source of background in thermal beamlines.

  14. Enhancing Neutron Beam Production with a Convoluted Moderator

    SciTech Connect

    Iverson, Erik B; Baxter, David V; Muhrer, Guenter; Ansell, Stuart; Gallmeier, Franz X; Dalgliesh, Robert; Lu, Wei; Kaiser, Helmut

    2014-10-01

    We describe a new concept for a neutron moderating assembly resulting in the more efficient production of slow neutron beams. The Convoluted Moderator, a heterogeneous stack of interleaved moderating material and nearly transparent single-crystal spacers, is a directionally-enhanced neutron beam source, improving beam effectiveness over an angular range comparable to the range accepted by neutron beam lines and guides. We have demonstrated gains of 50% in slow neutron intensity for a given fast neutron production rate while simultaneously reducing the wavelength-dependent emission time dispersion by 25%, both coming from a geometric effect in which the neutron beam lines view a large surface area of moderating material in a relatively small volume. Additionally, we have confirmed a Bragg-enhancement effect arising from coherent scattering within the single-crystal spacers. We have not observed hypothesized refractive effects leading to additional gains at long wavelength. In addition to confirmation of the validity of the Convoluted Moderator concept, our measurements provide a series of benchmark experiments suitable for developing simulation and analysis techniques for practical optimization and eventual implementation at slow neutron source facilities.

  15. A toolkit for epithermal neutron beam characterisation in BNCT.

    PubMed

    Auterinen, Iiro; Serén, Tom; Uusi-Simola, Jouni; Kosunen, Antti; Savolainen, Sauli

    2004-01-01

    Methods for dosimetry of epithermal neutron beams used in boron neutron capture therapy (BNCT) have been developed and utilised within the Finnish BNCT project as well as within a European project for a code of practise for the dosimetry of BNCT. One outcome has been a travelling toolkit for BNCT dosimetry. It consists of activation detectors and ionisation chambers. The free-beam neutron spectrum is measured with a set of activation foils of different isotopes irradiated both in a Cd-capsule and without it. Neutron flux (thermal and epithermal) distribution in phantoms is measured using activation of Mn and Au foils, and Cu wire. Ionisation chamber (IC) measurements are performed both in-free-beam and in-phantom for determination of the neutron and gamma dose components. This toolkit has also been used at other BNCT facilities in Europe, the USA, Argentina and Japan.

  16. Industrial applications of laser neutron source

    NASA Astrophysics Data System (ADS)

    Nakai, S.; Mima, K.; Kato, Y.; Tanaka, K.; Ikeda, Y.; Azechi, H.; Miyanaga, K.; Nakai, M.; Perlado, M.; Gonzalez Arrabal, R.

    2010-08-01

    The industrial applications of the intense neutron source have been widely explored because of the unique features of the neutron-matter interaction. Usually, intense neutron sources are assembled with fission reactors or high energy ion accelerators. The big size and high cost of these systems are the bottle neck to promote the industrial applications of intense neutrons. In this paper, we propose the compact laser driven neutron source for the industrial application. As the first step of our project for the versatile applications of laser driven neutron source, Li-neutron and/or Li-proton interactions have been investigated for the application to the development of Li battery.

  17. Neutron-induced gamma dose from a reactor beam filter for boron neutron capture therapy.

    PubMed

    Harrington, B V

    1989-01-01

    For the boron neutron capture therapy (NCT) of deep-seated metastatic melanoma, an epithermal (up to a few keV energy) neutron beam from a reactor horizontal facility could be useful if the inherent contamination from fast neutrons and gamma rays could be minimised. Calculations for ANSTO's 10 MW research reactor HIFAR have shown that, even though a filter material such as AlF3 attenuates the fast neutron dose, the beam quality improvement is counteracted by a relative increase in the gamma dose because of the gammas arising from neutron captures in the filter material, particularly the aluminium. The aluminium gammas, most of which arise from thermal neutron capture, are hard and cannot be attenuated by lead or bismuth without comparable attenuation of the epithermal neutron flux. Addition of an absorber such as 6Li to the AlF3 filter was investigated as a means of reducing the hard gamma dose, but the improvement in beam quality was small and at considerable cost to dose intensity. Dose characteristics calculations confirmed the superiority of a tangential beam over a radial beam with better results from an unfiltered tangential beam than from an AlF3 filter in a radial beam. This study showed conclusively that assessments of filter assemblies based on the effect of individual components on either the neutron or gamma dose in isolation are inadequate. In assessing any epithermal neutron filter, thermal neutron shield, and gamma shield combination, the total effect of each on the neutron, gamma, and boron-10 dose must be considered.

  18. The Spallation Neutron Source Beam Commissioning and Initial Operations

    SciTech Connect

    Henderson, Stuart; Aleksandrov, Alexander V.; Allen, Christopher K.; Assadi, Saeed; Bartoski, Dirk; Blokland, Willem; Casagrande, F.; Campisi, I.; Chu, C.; Cousineau, Sarah M.; Crofford, Mark T.; Danilov, Viatcheslav; Deibele, Craig E.; Dodson, George W.; Feshenko, A.; Galambos, John D.; Han, Baoxi; Hardek, T.; Holmes, Jeffrey A.; Holtkamp, N.; Howell, Matthew P.; Jeon, D.; Kang, Yoon W.; Kasemir, Kay; Kim, Sang-Ho; Kravchuk, L.; Long, Cary D.; McManamy, T.; Pelaia, II, Tom; Piller, Chip; Plum, Michael A.; Pogge, James R.; Purcell, John David; Shea, T.; Shishlo, Andrei P; Sibley, C.; Stockli, Martin P.; Stout, D.; Tanke, E.; Welton, Robert F; Zhang, Y.; Zhukov, Alexander P

    2015-09-01

    The Spallation Neutron Source (SNS) accelerator delivers a one mega-Watt beam to a mercury target to produce neutrons used for neutron scattering materials research. It delivers ~ 1 GeV protons in short (< 1 us) pulses at 60 Hz. At an average power of ~ one mega-Watt, it is the highest-powered pulsed proton accelerator. The accelerator includes the first use of superconducting RF acceleration for a pulsed protons at this energy. The storage ring used to create the short time structure has record peak particle per pulse intensity. Beam commissioning took place in a staged manner during the construction phase of SNS. After the construction, neutron production operations began within a few months, and one mega-Watt operation was achieved within three years. The methods used to commission the beam and the experiences during initial operation are discussed.

  19. Ion Beam Analysis of Targets Used in Controlatron Neutron Generators

    SciTech Connect

    Banks, James C.; Doyle, Barney L.; Walla, Lisa A.; Walsh, David S.

    2009-03-10

    Controlatron neutron generators are used for testing neutron detection systems at Sandia National Laboratories. To provide for increased tube lifetimes for the moderate neutron flux output of these generators, metal hydride (ZrT{sub 2}) target fabrication processes have been developed. To provide for manufacturing quality control of these targets, ion beam analysis techniques are used to determine film composition. The load ratios (i.e. T/Zr concentration ratios) of ZrT{sub 2} Controlatron neutron generator targets have been successfully measured by simultaneously acquiring RBS and ERD data using a He{sup ++} beam energy of 10 MeV. Several targets were measured and the film thicknesses obtained from RBS measurements agreed within {+-}2% with Dektak profilometer measurements. The target fabrication process and ion beam analysis techniques will be presented.

  20. Fast neutron beams--prospects for the coming decade.

    PubMed

    Blomgren, J

    2007-01-01

    The present status of neutron beam production techniques above 20 MeV is discussed. Presently, two main methods are used; white beams and quasi-monoenergetic beams. The performances of these two techniques are discussed, as well as the use of such facilities for measurements of nuclear data for fundamental and applied research. Recently, two novel ideas on how to produce extremely intense neutron beams in the 100-500 MeV range have been proposed. Decay in flight of beta delayed neutron-emitting nuclei could provide beam intensities five orders of magnitudes larger than present facilities. A typical neutron energy spectrum would be essentially monoenergetic, i.e., the energy spread is about 1 MeV with essentially no low-energy tail. A second option would be to produce beams of (6)He and dissociate the (6)He nuclei into alpha particles and neutrons. The basic features of these concepts are outlined, and the potential for improved nuclear data research is discussed. PMID:17502317

  1. BEAM LOSS MITIGATION IN THE OAK RIDGE SPALLATION NEUTRON SOURCE

    SciTech Connect

    Plum, Michael A

    2012-01-01

    The Oak Ridge Spallation Neutron Source (SNS) accelerator complex routinely delivers 1 MW of beam power to the spallation target. Due to this high beam power, understanding and minimizing the beam loss is an ongoing focus area of the accelerator physics program. In some areas of the accelerator facility the equipment parameters corresponding to the minimum loss are very different from the design parameters. In this presentation we will summarize the SNS beam loss measurements, the methods used to minimize the beam loss, and compare the design vs. the loss-minimized equipment parameters.

  2. Neutron fluence depth profiles in water phantom on epithermal beam of LVR-15 research reactor.

    PubMed

    Viererbl, L; Klupak, V; Lahodova, Z; Marek, M; Burian, J

    2010-01-01

    Horizontal channel with epithermal neutron beam at the LVR-15 research reactor is used mainly for boron neutron capture therapy. Neutron fluence depth profiles in a water phantom characterise beam properties. The neutron fluence (approximated by reaction rates) depth profiles were measured with six different types of activation detectors. The profiles were determined for thermal, epithermal and fast neutrons.

  3. Precision neutron flux measurements and applications using the Alpha Gamma device

    NASA Astrophysics Data System (ADS)

    Anderson, Eamon; Alpha Gamma; BL2 Collaboration

    2015-04-01

    The Alpha Gamma device is a totally-absorbing 10 B neutron detector designed to measure the absolute detection efficiency of a thin-film lithium neutron monitor on a monoenergetic neutron beam. The detector has been shown to measure neutron fluence with an absolute accuracy of 0.06%. This capability has been used to perform the first direct, absolute measurement of the 6Li(n , t) 4He cross section at sub-thermal energy, improve the neutron fluence determination in a past beam neutron lifetime measurement by a factor of five, and is being used to calibrate the neutron monitors for use in the upcoming beam neutron lifetime measurement BL2 (NIST Beam Lifetime 2). The principle of the measurement method will presented and the applications will be discussed. We would like to acknowledge support of this research through the NSF-PHY-1068712 grant as well as the NIST Precision Measurement Grant program.

  4. Precision neutron flux measurements and applications using the Alpha Gamma device

    NASA Astrophysics Data System (ADS)

    Anderson, Eamon

    2016-03-01

    The Alpha Gamma device is a totally-absorbing 10 B neutron detector designed to measure the absolute detection efficiency of a thin-film lithium neutron monitor on a monoenergetic neutron beam. The detector has been shown to measure neutron fluence with an absolute accuracy of 0.06%. This capability has been used to perform the first direct, absolute measurement of the 6Li(n,t) 4He cross section at sub-thermal energy, improve the neutron fluence determination in a past beam neutron lifetime measurement by a factor of five, and is being used to calibrate the neutron monitors for use in the upcoming beam neutron lifetime measurement BL2 (NIST Beam Lifetime 2). The principle of the measurement method will presented and the applications will be discussed. We would like to acknowledge support of this research through the NSF-PHY-1068712 Grant as well as the NIST Precision Measurement Grant program.

  5. GEM-based thermal neutron beam monitors for spallation sources

    NASA Astrophysics Data System (ADS)

    Croci, G.; Claps, G.; Caniello, R.; Cazzaniga, C.; Grosso, G.; Murtas, F.; Tardocchi, M.; Vassallo, E.; Gorini, G.; Horstmann, C.; Kampmann, R.; Nowak, G.; Stoermer, M.

    2013-12-01

    The development of new large area and high flux thermal neutron detectors for future neutron spallation sources, like the European Spallation Source (ESS) is motivated by the problem of 3He shortage. In the framework of the development of ESS, GEM (Gas Electron Multiplier) is one of the detector technologies that are being explored as thermal neutron sensors. A first prototype of GEM-based thermal neutron beam monitor (bGEM) has been built during 2012. The bGEM is a triple GEM gaseous detector equipped with an aluminum cathode coated by 1 μm thick B4C layer used to convert thermal neutrons to charged particles through the 10B(n,7Li)α nuclear reaction. This paper describes the results obtained by testing a bGEM detector at the ISIS spallation source on the VESUVIO beamline. Beam profiles (FWHMx=31 mm and FWHMy=36 mm), bGEM thermal neutron counting efficiency (≈1%), detector stability (3.45%) and the time-of-flight spectrum of the beam were successfully measured. This prototype represents the first step towards the development of thermal neutrons detectors with efficiency larger than 50% as alternatives to 3He-based gaseous detectors.

  6. Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

    NASA Astrophysics Data System (ADS)

    Alejo, A.; Green, A.; Ahmed, H.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; McKenna, P.; Mirfayzi, S. R.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.; Kar, S.

    2016-09-01

    The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher-catcher scenario, anisotropy in neutron emission was studied for the deuterium-deuterium fusion reaction. Simulation results are consistent with the narrow-divergence (∼ 70 ° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

  7. Fast slit-beam extraction and chopping for neutron generator

    NASA Astrophysics Data System (ADS)

    Kalvas, T.; Hahto, S. K.; Gicquel, F.; King, M.; Vainionpää, J. H.; Reijonen, J.; Leung, K. N.; Miller, T. G.

    2006-03-01

    High-intensity fast white neutron pulses are needed for pulsed fast neutron transmission spectroscopy (PFNTS). A compact tritium-tritium fusion reaction neutron generator with an integrated ion beam chopping system has been designed, simulated, and tested for PFNTS. The design consists of a toroidal plasma chamber with 20 extraction slits, concentric cylindrical electrodes, chopper plates, and a central titanium-coated beam target. The total ion beam current is 1A. The beam chopping is done at 30keV energy with a parallel-plate deflector integrated with an Einzel lens. Beam pulses with 5ns width can be achieved with a 15ns rise/fall time ±1500V sweep on the chopper plates. The neutrons are produced at 120keV energy. A three-dimensional simulation code based on Vlasov iteration was developed for simulating the ion optics of this system. The results with this code were found to be consistent with other simulation codes. So far we have measured 50ns ion beam pulses from the system.

  8. Fast slit-beam extraction and chopping for neutron generator

    SciTech Connect

    Kalvas, T.; Hahto, S.K.; Gicquel, F.; King, M.; Vainionpaeae, J.H.; Reijonen, J.; Leung, K.N.; Miller, T.G.

    2006-03-15

    High-intensity fast white neutron pulses are needed for pulsed fast neutron transmission spectroscopy (PFNTS). A compact tritium-tritium fusion reaction neutron generator with an integrated ion beam chopping system has been designed, simulated, and tested for PFNTS. The design consists of a toroidal plasma chamber with 20 extraction slits, concentric cylindrical electrodes, chopper plates, and a central titanium-coated beam target. The total ion beam current is 1 A. The beam chopping is done at 30 keV energy with a parallel-plate deflector integrated with an Einzel lens. Beam pulses with 5 ns width can be achieved with a 15 ns rise/fall time {+-}1500 V sweep on the chopper plates. The neutrons are produced at 120 keV energy. A three-dimensional simulation code based on Vlasov iteration was developed for simulating the ion optics of this system. The results with this code were found to be consistent with other simulation codes. So far we have measured 50 ns ion beam pulses from the system.

  9. Performance of a Medium-Size Area nGEM Detector for Neutron Beam Diagnostics

    NASA Astrophysics Data System (ADS)

    Croci, G.; Cazzaniga, C.; Albani, G.; Muraro, A.; Claps, G.; Cavenago, M.; Grosso, G.; Murtas, F.; Pasqualotto, R.; Cippo, E. Perelli; Rebai, M.; Tardocchi, M.; Gorini, G.

    Fast neutron detectors with a sub-centimetric space resolution are required in order to qualify neutron beams in applications related to magnetically-controlled nuclear fusion plasmas and to spallation sources. Based on the results obtained with small area prototypes, the first medium-size (20 x 35.2 cm2 active area) nGEM detector has been realized for both the CNESM diagnostic system of the SPIDER NBI prototype for ITER and as a beam monitor for fast neutrons beam lines at spallation sources, too. The nGEM is a Triple GEM gaseous detector equipped with polyethylene layers used to convert fast neutrons into recoil protons through the elastic scattering process. This paper describes the performance of the medium-size nGEM detector tested at the VESUVIO beam line of the ISIS spallation source. Being this detector the actual largest area fast neutron detector based on the GEM technology, particular attention was paid in the study of detector response in different points over the active area. Measurements of GEM counting rate (both as a function of VGEM and of time) and of the capability of the detector to reconstruct the beam in different positions are presented. This detector serves as a basis for the realization of an even larger area detector that will be used in the MITICA NBI prototype for ITER that represents the evolution of SPIDER.

  10. A Drabkin-type spin resonator as tunable neutron beam monochromator

    NASA Astrophysics Data System (ADS)

    Piegsa, F. M.; Ries, D.; Filges, U.; Hautle, P.

    2015-09-01

    A Drabkin-type spin resonator was designed and successfully implemented at the multi-purpose beam line BOA at the spallation neutron source SINQ at the Paul Scherrer Institute. The device selectively acts on the magnetic moment of neutrons within an adjustable velocity band and hence can be utilized as a tunable neutron beam monochromator. Several neutron time-of-flight (TOF) spectra have been recorded employing various settings in order to characterize its performance. In a first test application the velocity dependent transmission of a beryllium filter was determined. In addition, we demonstrate that using an exponential current distribution in the spin resonator coil the side-maxima in the TOF spectra usually associated with a Drabkin setup can be strongly suppressed.

  11. Fluence and dose measurements for an accelerator neutron beam

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Byun, S. H.; McNeill, F. E.; Mothersill, C. E.; Seymour, C. B.; Prestwich, W. V.

    2007-10-01

    The 3 MV Van de Graaff accelerator at McMaster University accelerator laboratory is extended to a neutron irradiation facility for low-dose bystander effects research. A long counter and an Anderson-Braun type neutron monitor have been used as monitors for the determination of the total fluence. Activation foils were used to determine the thermal neutron fluence rate (around 106 neutrons s-1). Meanwhile, the interactions of neutrons with the monitors have been simulated using a Monte Carlo N Particle (MCNP) code. Bystander effects, i.e. damage occurring in cells that were not traversed by radiation but were in the same radiation environment, have been well observed following both alpha and gamma irradiation of many cell lines. Since neutron radiation involves mixed field (including gamma and neutron radiations), we need to differentiate the doses for the bystander effects from the two radiations. A tissue equivalent proportional counter (TEPC) filled with propane based tissue equivalent gas simulating a 2 μm diameter tissue sphere has been investigated to estimate the neutron and gamma absorbed doses. A photon dose contamination of the neutron beam is less than 3%. The axial dose distribution follows the inverse square law and lateral and vertical dose distributions are relatively uniform over the irradiation area required by the biological study.

  12. Response investigations of a TEPC in high energy proton and neutron beams using the variance method.

    PubMed

    Kyllönen, J E; Grindborg, J E; Lindborg, L

    2002-01-01

    Results from measurements in proton and neutron beams between 68 and 174 MeV at the T. Svedberg Laboratory in Uppsala are presented. The result indicate that a TEPC might underestimate the high-energy contribution to H*(10) in cosmic radiation applications such as measurements onboard aircraft.

  13. Low-energy beam transport studies supporting the Spallation Neutron Source 1-MW beam operationa

    SciTech Connect

    Han, Baoxi; Kalvas, T.; Tarvainen, O.; Welton, Robert F; Murray Jr, S N; Pennisi, Terry R; Santana, Manuel; Stockli, Martin P

    2012-01-01

    The H- injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the Spallation Neutron Source 1-MW beam operation with ~38 mA beam current in the linac at 60 Hz with a pulse length of up to ~1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: 1) inconsistent dependence of the post-RFQ beam current on the ion source tilt angle, and 2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  14. A molecular beam epitaxy facility for in situ neutron scattering

    SciTech Connect

    Dura, J. A.; LaRock, J.

    2009-07-15

    A molecular beam epitaxy (MBE) facility has been built to enable in situ neutron scattering measurements during growth of epitaxial layers. While retaining the full capabilities of a research MBE chamber, this facility has been optimized for polarized neutron reflectometry measurements. Optimization includes a compact lightweight portable design, a neutron window, controllable magnetic field, deposition across a large 76 mm diameter sample with exceptional flux uniformity, and sample temperatures continuously controllable from 38 to 1375 K. A load lock chamber allows for sample insertion, storage of up to 4 samples, and docking with other facilities. The design and performance of this chamber are described here.

  15. Boron neutron capture therapy (BNCT): implications of neutron beam and boron compound characteristics.

    PubMed

    Wheeler, F J; Nigg, D W; Capala, J; Watkins, P R; Vroegindeweij, C; Auterinen, I; Seppälä, T; Bleuel, D

    1999-07-01

    The potential efficacy of boron neutron capture therapy (BNCT) for malignant glioma is a significant function of epithermal-neutron beam biophysical characteristics as well as boron compound biodistribution characteristics. Monte Carlo analyses were performed to evaluate the relative significance of these factors on theoretical tumor control using a standard model. The existing, well-characterized epithermal-neutron sources at the Brookhaven Medical Research Reactor (BMRR), the Petten High Flux Reactor (HFR), and the Finnish Research Reactor (FiR-1) were compared. Results for a realistic accelerator design by the E. O. Lawrence Berkeley National Laboratory (LBL) are also compared. Also the characteristics of the compound p-Boronophenylaline Fructose (BPA-F) and a hypothetical next-generation compound were used in a comparison of the BMRR and a hypothetical improved reactor. All components of dose induced by an external epithermal-neutron beam fall off quite rapidly with depth in tissue. Delivery of dose to greater depths is limited by the healthy-tissue tolerance and a reduction in the hydrogen-recoil and incident gamma dose allow for longer irradiation and greater dose at a depth. Dose at depth can also be increased with a beam that has higher neutron energy (without too high a recoil dose) and a more forward peaked angular distribution. Of the existing facilities, the FiR-1 beam has the better quality (lower hydrogen-recoil and incident gamma dose) and a penetrating neutron spectrum and was found to deliver a higher value of Tumor Control Probability (TCP) than other existing beams at shallow depth. The greater forwardness and penetration of the HFR the FiR-1 at greater depths. The hypothetical reactor and accelerator beams outperform at both shallow and greater depths. In all cases, the hypothetical compound provides a significant improvement in efficacy but it is shown that the full benefit of improved compound is not realized until the neutron beam is fully

  16. Diamond detector for high rate monitors of fast neutrons beams

    SciTech Connect

    Giacomelli, L.; Rebai, M.; Cippo, E. Perelli; Tardocchi, M.; Fazzi, A.; Andreani, C.; Pietropaolo, A.; Frost, C. D.; Rhodes, N.; Schooneveld, E.; Gorini, G.

    2012-06-19

    A fast neutron detection system suitable for high rate measurements is presented. The detector is based on a commercial high purity single crystal diamond (SDD) coupled to a fast digital data acquisition system. The detector was tested at the ISIS pulsed spallation neutron source. The SDD event signal was digitized at 1 GHz to reconstruct the deposited energy (pulse amplitude) and neutron arrival time; the event time of flight (ToF) was obtained relative to the recorded proton beam signal t{sub 0}. Fast acquisition is needed since the peak count rate is very high ({approx}800 kHz) due to the pulsed structure of the neutron beam. Measurements at ISIS indicate that three characteristics regions exist in the biparametric spectrum: i) background gamma events of low pulse amplitudes; ii) low pulse amplitude neutron events in the energy range E{sub dep}= 1.5-7 MeV ascribed to neutron elastic scattering on {sup 12}C; iii) large pulse amplitude neutron events with E{sub n} < 7 MeV ascribed to {sup 12}C(n,{alpha}){sup 9}Be and 12C(n,n')3{alpha}.

  17. Nonpropulsive applications of ion beams

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    Eight centimeter ion beam sources utilizing xenon and argon have been developed that operate over a wide range of beam energies and currents. Three types of processes have been studied: sputter deposition, ion beam machining, and ion beam surface texturing. The broad range of source operating conditions allows optimum sputter deposition of various materials. An ion beam source was used to ion mill laser reflection holograms using photoresist patterns on silicon. Ion beam texturing was tried with many materials and has a multitude of potential applications.

  18. Microstructured silicon neutron detectors for security applications

    NASA Astrophysics Data System (ADS)

    Esteban, S.; Fleta, C.; Guardiola, C.; Jumilla, C.; Pellegrini, G.; Quirion, D.; Rodriguez, J.; Lozano, M.

    2014-12-01

    In this paper we present the design and performance of a perforated thermal neutron silicon detector with a 6LiF neutron converter. This device was manufactured within the REWARD project workplace whose aim is to develop and enhance technologies for the detection of nuclear and radiological materials. The sensor perforated structure results in a higher efficiency than that obtained with an equivalent planar sensor. The detectors were tested in a thermal neutron beam at the nuclear reactor at the Instituto Superior Técnico in Lisbon and the intrinsic detection efficiency for thermal neutrons and the gamma sensitivity were obtained. The Geant4 Monte Carlo code was used to simulate the experimental conditions, i.e. thermal neutron beam and the whole detector geometry. An intrinsic thermal neutron detection efficiency of 8.6%±0.4% with a discrimination setting of 450 keV was measured.

  19. Designing accelerator-based epithermal neutron beams for boron neutron capture therapy

    SciTech Connect

    Bleuel, D.L. |; Donahue, R.J.; Ludewigt, B.A.; Vujic, J.

    1998-09-01

    The {sup 7}Li(p,n){sup 7}Be reaction has been investigated as an accelerator-driven neutron source for proton energies between 2.1 and 2.6 MeV. Epithermal neutron beams shaped by three moderator materials, Al/AlF{sub 3}, {sup 7}LiF, and D{sub 2}O, have been analyzed and their usefulness for boron neutron capture therapy (BNCT) treatments evaluated. Radiation transport through the moderator assembly has been simulated with the Monte Carlo {ital N}-particle code (MCNP). Fluence and dose distributions in a head phantom were calculated using BNCT treatment planning software. Depth-dose distributions and treatment times were studied as a function of proton beam energy and moderator thickness. It was found that an accelerator-based neutron source with Al/AlF{sub 3} or {sup 7}LiF as moderator material can produce depth-dose distributions superior to those calculated for a previously published neutron beam design for the Brookhaven Medical Research Reactor, achieving up to {approximately}50{percent} higher doses near the midline of the brain. For a single beam treatment, a proton beam current of 20 mA, and a {sup 7}LiF moderator, the treatment time was estimated to be about 40 min. The tumor dose deposited at a depth of 8 cm was calculated to be about 21 Gy-Eq. {copyright} {ital 1998 American Association of Physicists in Medicine.}

  20. Physics with Ultracold and Thermal Neutron Beams

    SciTech Connect

    Steyerl, Albert

    2004-08-10

    This project has been focused on a measurement of the mean lifetime {tau}{sub n} of the free neutron with a precision better than 0.1%. The neutron {beta}-decay n {yields} p + e{sup -} + {bar {nu}}{sub e} + 783 keV into a proton, electron and electron antineutrino is the prototype semi-leptonic weak decay, involving both leptons and hadrons in the first generation of elementary particles. Within the standard V-A theory of weak interaction, it is governed by only two constants: the vector coupling constant g{sub V}, and axial vector constant g{sub A}. The neutron lifetime has been measured many times over decades, and the present (2004) world-average, {tau}{sub n} = 885.7 {+-} 0.8 s, has a weighted error of {approx}0.1% while individual uncertainties are typically 2-10 seconds for high precision data. The highest precision claimed by an individual measurement is {approx}0.15%. An improvement is required to resolve issues of the Standard Model of the electro-weak interaction as well as of astrophysics and of Big Bang theories. The focus in astrophysics is the solar neutrino deficit problem, which requires a precise value of g{sub A}. Big Bang theories require a precise {tau}{sub n}-value to understand the primordial He/H ratio. The strong interest of particle physicists in {tau}{sub n} is mainly based on a possible difficulty with the Cabibbo Kobayashi Maskawa (CKM) matrix, which describes the mixing of quark mass states by the weak interaction. Nuclear, neutron, and pion decay data, probing the mixing amplitude V{sub ud} within the first quark generation, in combination with K and B meson decay data, which probe the second and third generation (V{sub us} and V{sub ub}), indicate a departure from the unitarity demanded by all gauge-invariant theories. The deviation of the first-row sum |V{sub ud}|{sup 2} + |V{sub us}|{sup 2} + |V{sub ub}|{sup 2} from unity is on the 2.3 sigma level. Including a new value for V{sub us} would remove the discrepancy; but the authors of

  1. Simulation of spatial fuel assay using HANARO neutron beam

    PubMed

    Lee; Chang; Lee; Kim

    2000-10-01

    A sensitivity simulation of neutron tomography was performed for the analysis of the spatial distribution of nuclear materials in the HANARO fuel rod. The internal distribution of the nuclear materials in the fuel rod is very important for the increase of the safety and economics of fuel burnup in the reactor. The neutron radiography facility installed at HANARO will be used for the spatial fuel analysis with a real-time image processing system. Monte Carlo simulation was performed to study the feasibility and sensitivity of the HANARO neutron beam for the spatial fuel assay and to find the optimum conditions for neutron detection. From the sensitivity simulation, the location of the nuclear materials in the rod was evident as expected. PMID:11003495

  2. Modification of the radial beam port of ITU TRIGA Mark II research reactor for BNCT applications.

    PubMed

    Akan, Zafer; Türkmen, Mehmet; Çakir, Tahir; Reyhancan, İskender A; Çolak, Üner; Okka, Muhittin; Kiziltaş, Sahip

    2015-05-01

    This paper aims to describe the modification of the radial beam port of ITU (İstanbul Technical University) TRIGA Mark II research reactor for BNCT applications. Radial beam port is modified with Polyethylene and Cerrobend collimators. Neutron flux values are measured by neutron activation analysis (Au-Cd foils). Experimental results are verified with Monte Carlo results. The results of neutron/photon spectrum, thermal/epithermal neutron flux, fast group photon fluence and change of the neutron fluxes with the beam port length are presented.

  3. Modification of the radial beam port of ITU TRIGA Mark II research reactor for BNCT applications.

    PubMed

    Akan, Zafer; Türkmen, Mehmet; Çakir, Tahir; Reyhancan, İskender A; Çolak, Üner; Okka, Muhittin; Kiziltaş, Sahip

    2015-05-01

    This paper aims to describe the modification of the radial beam port of ITU (İstanbul Technical University) TRIGA Mark II research reactor for BNCT applications. Radial beam port is modified with Polyethylene and Cerrobend collimators. Neutron flux values are measured by neutron activation analysis (Au-Cd foils). Experimental results are verified with Monte Carlo results. The results of neutron/photon spectrum, thermal/epithermal neutron flux, fast group photon fluence and change of the neutron fluxes with the beam port length are presented. PMID:25746919

  4. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    PubMed

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values.

  5. High-Current Experiments for Accelerator-Based Neutron Capture Therapy Applications

    SciTech Connect

    Gierga, D.P.; Klinkowstein, R.E.; Hughey, B.H.; Shefer, R.E.; Yanch, J.C.; Blackburn, B.W.

    1999-06-06

    Several accelerator-based neutron capture therapy applications are under development. These applications include boron neutron capture therapy for glioblastoma multiform and boron neutron capture synovectomy (BNCS) for rheumatoid arthritis. These modalities use accelerator-based charged-particle reactions to create a suitable neutron source. Neutrons are produced using a high-current, 2-MV terminal tandem accelerator. For these applications to be feasible, high accelerator beam currents must be routinely achievable. An effort was undertaken to explore the operating regime of the accelerator in the milliampere range. In preparation for high-current operation of the accelerator, computer simulations of charged-particle beam optics were performed to establish high-current operating conditions. Herein we describe high beam current simulations and high beam current operation of the accelerator.

  6. A Sealed-Accelerator-Tube Neutron Generator for Boron Neutron Capture Therapy Application

    SciTech Connect

    Leung, K.-N.; Leung, K.N.; Lee, Y.; Verbeke, J.M.; Vurjic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1998-06-01

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator applications. By using a 2.5-cm-diameter RF-driven multicusp source and a computer designed 100 keV accelerator column, peak extractable hydrogen current exceeding 1 A from a 3-mm-diameter aperture, together with H{sup +} yields over 94% have been achieved. These experimental findings together with recent moderator design will enable one to develop compact 14 MeV neutron generators based on the D-T fusion reaction. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without pumping. With a 120 keV and 1 A deuteron beam, it is estimated that a treatment time of {approx} 45 minutes is needed for boron neutron capture therapy.

  7. Application of imaging plate neutron detector to neutron radiography

    NASA Astrophysics Data System (ADS)

    Fujine, Shigenori; Yoneda, Kenji; Kamata, Masahiro; Etoh, Masahiro

    1999-11-01

    As an imaging plate neutron detector (IP-ND) has been available for thermal neutron radiography (TNR) which has high resolution, high sensitivity and wide range, some basic characteristics of the IP-ND system were measured at the E-2 facility of the KUR. After basic performances of the IP were studied, images with high quality were obtained at a neutron fluence of 2 to 7×10 8 n cm -2. It was found that the IP-ND system with Gd 2O 3 as a neutron converter material has a higher sensitivity to γ-ray than that of a conventional film method. As a successful example, clear radiographs of the flat view for the fuel side plates with boron burnable poison were obtained. An application of the IP-ND system to neutron radiography (NR) is presented in this paper.

  8. Heat generation and neutron beam characteristics in a high power pulsed spallation neutron source

    SciTech Connect

    Jerng, D.W.; Carpenter, J.M.

    1996-11-01

    In the course of conceptual design of a high power pulsed spallation source, a Monte Carlo model was developed for heat generation and neutronics studies. In this paper, we present two sets of results. The first set of calculations was performed with a simple target model to investigate general characteristics of power distribution and neutron production with various proton energies ranging from 0.8 to 12 GeV. The second set was performed with a realistic target model including major components of the target system to provide basic parameters for engineering design of a high power pulsed spallation source. Calculated results generally confirm that higher proton energy provides and advantage in target cooling system requirements and yet somewhat lower neutron beam intensity as a counter effect. The heat generation in the systems surrounding the target was investigated in detail and found to have important variation with position and according to proton beam energy. Calculations of the neutron currents from the moderators showed that the neutron beam intensity from moderators in the front region of the target decreased fro higher proton energy while that from moderators in the back region of the target remained almost unchanged.

  9. System and method for delivery of neutron beams for medical therapy

    DOEpatents

    Nigg, David W.; Wemple, Charles A.

    1999-01-01

    A neutron delivery system that provides improved capability for tumor control during medical therapy. The system creates a unique neutron beam that has a bimodal or multi-modal energy spectrum. This unique neutron beam can be used for fast-neutron therapy, boron neutron capture therapy (BNCT), or both. The invention includes both an apparatus and a method for accomplishing the purposes of the invention.

  10. System and method for delivery of neutron beams for medical therapy

    DOEpatents

    Nigg, D.W.; Wemple, C.A.

    1999-07-06

    A neutron delivery system that provides improved capability for tumor control during medical therapy is disclosed. The system creates a unique neutron beam that has a bimodal or multi-modal energy spectrum. This unique neutron beam can be used for fast-neutron therapy, boron neutron capture therapy (BNCT), or both. The invention includes both an apparatus and a method for accomplishing the purposes of the invention. 5 figs.

  11. Neutron production from beam-modifying devices in a modern double scattering proton therapy beam delivery system

    PubMed Central

    Pérez-Andújar, Angélica; Newhauser, Wayne D; DeLuca, Paul M

    2014-01-01

    In this work the neutron production in a passive beam delivery system was investigated. Secondary particles including neutrons are created as the proton beam interacts with beam shaping devices in the treatment head. Stray neutron exposure to the whole body may increase the risk that the patient develops a radiogenic cancer years or decades after radiotherapy. We simulated a passive proton beam delivery system with double scattering technology to determine the neutron production and energy distribution at 200 MeV proton energy. Specifically, we studied the neutron absorbed dose per therapeutic absorbed dose, the neutron absorbed dose per source particle and the neutron energy spectrum at various locations around the nozzle. We also investigated the neutron production along the nozzle's central axis. The absorbed doses and neutron spectra were simulated with the MCNPX Monte Carlo code. The simulations revealed that the range modulation wheel (RMW) is the most intense neutron source of any of the beam spreading devices within the nozzle. This finding suggests that it may be helpful to refine the design of the RMW assembly, e.g., by adding local shielding, to suppress neutron-induced damage to components in the nozzle and to reduce the shielding thickness of the treatment vault. The simulations also revealed that the neutron dose to the patient is predominated by neutrons produced in the field defining collimator assembly, located just upstream of the patient. PMID:19147903

  12. Design and simulations of the neutron dump for the back-streaming white neutron beam at CSNS

    NASA Astrophysics Data System (ADS)

    Zhang, L. Y.; Jing, H. T.; Tang, J. Y.; Wang, X. Q.

    2016-10-01

    For nuclear data measurements with a white neutron source, to control the background at the detector is a key issue. The neutron dump which locates at the end of the white neutron beam line at CSNS has a very important impact to the neutron and gamma backgrounds in the endstation. A sophisticated neutron dump was designed to reduce the backgrounds to the level of about 10-8 relative to the neutron flux. In this paper, the method to suppress both neutron and gamma backgrounds near a white-spectrum neutron dump is introduced. The optimized geometry structure and materials of the dump are described, and the neutron and gamma space distributions have been calculated by using the FLUKA code for different operation settings which are defined by beam spots of Φ30 mm, Φ60 mm and 90 mm×90 mm, respectively.

  13. Vertical neutron beam focusing with bent mosaic crystals

    NASA Astrophysics Data System (ADS)

    Courtois, P.

    2016-09-01

    We report on the performance of bent mosaic crystals when used as a vertical focusing neutron monochromator. High-quality Cu(200) and Ge(335) mosaic crystals with a controlled curvature have been successfully produced at the ILL using plastic deformation at high temperature. As expected from simple geometrical considerations, they exhibit excellent properties for focusing a neutron beam vertically when examined on a high-resolution diffractometer installed on an m = 1 thermal neutron guide. Both Cu(200) and Ge(335) curved crystals allow a significant reduction of the focal image size at the sample position compared with a flat crystal with the same defect concentration. As a result, significant gain factors of 6 to 7 in intensity were obtained by replacing a flat crystal of 30 mm with a bent crystal.

  14. Neutronics Assessments for a RIA Fragmentation Line Beam Dump Concept

    SciTech Connect

    Boles, J L; Reyes, S; Ahle, L E; Stein, W

    2005-05-13

    Heavy ion and radiation transport calculations are in progress for conceptual beam dump designs for the fragmentation line of the proposed Rare Isotope Accelerator (RIA). Using the computer code PHITS, a preliminary design of a motor-driven rotating wheel beam dump and adjacent downstream multipole has been modeled. Selected results of these calculations are given, including neutron and proton flux in the wheel, absorbed dose and displacements per atom in the hub materials, and heating from prompt radiation and from decay heat in the multipole.

  15. Ion source and beam guiding studies for an API neutron generator

    SciTech Connect

    Sy, A.; Ji, Q.; Persaud, A.; Ludewigt, B. A.; Schenkel, T.

    2013-04-19

    Recently developed neutron imaging methods require high neutron yields for fast imaging times and small beam widths for good imaging resolution. For ion sources with low current density to be viable for these types of imaging methods, large extraction apertures and beam focusing must be used. We present recent work on the optimization of a Penning-type ion source for neutron generator applications. Two multi-cusp magnet configurations have been tested and are shown to increase the extracted ion current density over operation without multi-cusp magnetic fields. The use of multi-cusp magnetic confinement and gold electrode surfaces have resulted in increased ion current density, up to 2.2 mA/cm{sup 2}. Passive beam focusing using tapered dielectric capillaries has been explored due to its potential for beam compression without the cost and complexity issues associated with active focusing elements. Initial results from first experiments indicate the possibility of beam compression. Further work is required to evaluate the viability of such focusing methods for associated particle imaging (API) systems.

  16. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility.

    PubMed

    Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2016-01-01

    The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively. PMID:26595774

  17. Demonstration of the importance of a dedicated neutron beam monitoring system for BNCT facility.

    PubMed

    Chao, Der-Sheng; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2016-01-01

    The neutron beam monitoring system is indispensable to BNCT facility in order to achieve an accurate patient dose delivery. The neutron beam monitoring of a reactor-based BNCT (RB-BNCT) facility can be implemented through the instrumentation and control system of a reactor provided that the reactor power level remains constant during reactor operation. However, since the neutron flux in reactor core is highly correlative to complicated reactor kinetics resulting from such as fuel depletion, poison production, and control blade movement, some extent of variation may occur in the spatial distribution of neutron flux in reactor core. Therefore, a dedicated neutron beam monitoring system is needed to be installed in the vicinity of the beam path close to the beam exit of the RB-BNCT facility, where it can measure the BNCT beam intensity as closely as possible and be free from the influence of the objects present around the beam exit. In this study, in order to demonstrate the importance of a dedicated BNCT neutron beam monitoring system, the signals originating from the two in-core neutron detectors installed at THOR were extracted and compared with the three dedicated neutron beam monitors of the THOR BNCT facility. The correlation of the readings between the in-core neutron detectors and the BNCT neutron beam monitors was established to evaluate the improvable quality of the beam intensity measurement inferred by the in-core neutron detectors. In 29 sampled intervals within 16 days of measurement, the fluctuations in the mean value of the normalized ratios between readings of the three BNCT neutron beam monitors lay within 0.2%. However, the normalized ratios of readings of the two in-core neutron detectors to one of the BNCT neutron beam monitors show great fluctuations of 5.9% and 17.5%, respectively.

  18. Dual-fission chamber and neutron beam characterization for fission product yield measurements using monoenergetic neutrons

    NASA Astrophysics Data System (ADS)

    Bhatia, C.; Fallin, B.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E. M.; Bredeweg, T. A.; Fowler, M. M.; Moody, W. A.; Rundberg, R. S.; Rusev, G.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

    2014-09-01

    A program has been initiated to measure the energy dependence of selected high-yield fission products used in the analysis of nuclear test data. We present out initial work of neutron activation using a dual-fission chamber with quasi-monoenergetic neutrons and gamma-counting method. Quasi-monoenergetic neutrons of energies from 0.5 to 15 MeV using the TUNL 10 MV FM tandem to provide high-precision and self-consistent measurements of fission product yields (FPY). The final FPY results will be coupled with theoretical analysis to provide a more fundamental understanding of the fission process. To accomplish this goal, we have developed and tested a set of dual-fission ionization chambers to provide an accurate determination of the number of fissions occurring in a thick target located in the middle plane of the chamber assembly. Details of the fission chamber and its performance are presented along with neutron beam production and characterization. Also presented are studies on the background issues associated with room-return and off-energy neutron production. We show that the off-energy neutron contribution can be significant, but correctable, while room-return neutron background levels contribute less than <1% to the fission signal.

  19. Simulation study of accelerator based quasi-mono-energetic epithermal neutron beams for BNCT.

    PubMed

    Adib, M; Habib, N; Bashter, I I; El-Mesiry, M S; Mansy, M S

    2016-01-01

    Filtered neutron techniques were applied to produce quasi-mono-energetic neutron beams in the energy range of 1.5-7.5 keV at the accelerator port using the generated neutron spectrum from a Li (p, n) Be reaction. A simulation study was performed to characterize the filter components and transmitted beam lines. The feature of the filtered beams is detailed in terms of optimal thickness of the primary and additive components. A computer code named "QMNB-AS" was developed to carry out the required calculations. The filtered neutron beams had high purity and intensity with low contamination from the accompanying thermal, fast neutrons and γ-rays.

  20. Neutron Tube Design Study for Boron Neutron Capture TherapyApplication

    SciTech Connect

    Verbeke, J.M.; Lee, Y.; Leung, K.N.; Vujic, J.; Williams, M.D.; Wu, L.K.; Zahir, N.

    1998-01-04

    Radio-frequency (RF) driven ion sources are being developed in Lawrence Berkeley National Laboratory (LBNL) for sealed-accelerator-tube neutron generator application. By using a 5-cm-diameter RF-driven multicusp source H{sup +} yields over 95% have been achieved. These experimental findings will enable one to develop compact neutron generators based on the D-D or D-T fusion reactions. In this new neutron generator, the ion source, the accelerator and the target are all housed in a sealed metal container without external pumping. Recent moderator design simulation studies have shown that 14 MeV neutrons could be moderated to therapeutically useful energy ranges for boron neutron capture therapy (BNCT). The dose near the center of the brain with optimized moderators is about 65% higher than the dose obtained from a typical neutron spectrum produced by the Brookhaven Medical Research Reactor (BMRR), and is comparable to the dose obtained by other accelerator-based neutron sources. With a 120 keV and 1 A deuteron beam, a treatment time of {approx}35 minutes is estimated for BNCT.

  1. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

    SciTech Connect

    Han, B. X.; Welton, R. F.; Murray, S. N. Jr.; Pennisi, T. R.; Santana, M.; Stockli, M. P.; Kalvas, T.; Tarvainen, O.

    2012-02-15

    The H{sup -} injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with {approx}38 mA beam current in the linac at 60 Hz with a pulse length of up to {approx}1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  2. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

    SciTech Connect

    Kalvas, T.; Welton, Robert F; Pennisi, Terry R

    2012-01-01

    The H{sup -} injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with {approx}38 mA beam current in the linac at 60 Hz with a pulse length of up to {approx}1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  3. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation.

    PubMed

    Han, B X; Kalvas, T; Tarvainen, O; Welton, R F; Murray, S N; Pennisi, T R; Santana, M; Stockli, M P

    2012-02-01

    The H(-) injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with ∼38 mA beam current in the linac at 60 Hz with a pulse length of up to ∼1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  4. Tagged fast neutron beams En > 6 MeV

    SciTech Connect

    Favela, F.; Huerta, A.; Santa Rita, P.; Ramos, A. T.; Lucio, O. de; Andrade, E.; Ortiz, M. E.; Araujo, V.; Chávez, E.; Acosta, L.; Murillo, G.; Policroniades, R.

    2015-07-23

    Controlled flux of neutrons are produced through the {sup 14}N(d,n){sup 15}O nuclear reaction. Deuteron beams (2-4 MeV) are delivered by the CN-Van de Graaff accelerator and directed with full intensity to our Nitrogen target at SUGAR (SUpersonic GAs jet taRget). Each neutron is electronically tagged by the detection of the associated{sup 15}O. Its energy and direction are known and “beams” of fast monochromatic tagged neutrons (E{sub n}> 6 MeV) are available for basic research and applied work. MONDE is a large area (158 × 63 cm{sup 2}) plastic scintillating slab (5 cm thick), viewed by 16 PMTs from the sides. Fast neutrons (MeV) entering the detector will produce a recoiling proton that induces a light spark at the spot. Signals from the 16 detectors are processed to deduce the position of the spark. Time logic signals from both the {sup 15}O detector and MONDE are combined to deduce a time of flight (TOF) signal. Finally, the position information together with the TOF yields the full momentum vector of each detected neutron.

  5. A Technique for Determining Neutron Beam Fluence to 0.01% Uncertainty

    SciTech Connect

    Yue, A. T.; Dewey, M. S.; Gilliam, D. M.; Nico, J. S.; Fomin, N.; Greene, G. L.; Snow, W. M.; Wietfeldt, F. E.

    2014-01-01

    The achievable uncertainty in neutron lifetime measurements using the beam technique has been limited by the uncertainty in the determination of the neutron density in the decay volume. In the Sussex-ILL-NIST series of beam lifetime experiments, the density was determined with a neutron fluence mon itor that detected the charged particle products from neutron absorption in a thin layer of 6Li or lOB. In each of the experiments, the absolute detection efficiency of the neutron monitor was determined from the measured density of the neutron absorber, the thermal neutron cross section for the absorbing ma terial, and the solid angle of the charged particle detectors. The efficiency of the neutron monitor used in the most recent beam lifetime experiment has since been measured directly by operating it on a monochromatic neutron beam in which the total neutron rate is determined with a totally absorbing neutron detector. The absolute nature of this technique does not rely on any knowl edge of neutron absorption cross sections or a measurement of the density of the neutron absorbing deposit. This technique has been used to measure the neutron monitor efficiency to 0.06% uncertainty. VVe show that a new monitor and absolute neutron detector employing the same technique would be capable of achieving determining neutron fluence to an uncertainty of 0.01%.

  6. Measurement of Neutrons Produced by Beam-Target Interactions via a Coaxial Plasma Accelerator

    NASA Astrophysics Data System (ADS)

    Cauble, Scott; Poehlmann, Flavio; Rieker, Gregory; Cappelli, Mark

    2011-10-01

    This poster presents a method to measure neutron yield from a coaxial plasma accelerator. Stored electrical energies between 1 and 19 kJ are discharged within a few microseconds across the electrodes of the coaxial gun, accelerating deuterium gas samples to plasma beam energies well beyond the keV energy range. The focus of this study is to examine the interaction of the plasma beam with a deuterated target by designing and fabricating a detector to measure neutron yield. Given the strong electromagnetic pulse associated with our accelerator, indirect measurement of neutrons via threshold-dependent nuclear activation serves as both a reliable and definitive indicator of high-energy particles for our application. Upon bombardment with neutrons, discs or stacks of metal foils placed near the deuterated target undergo nuclear activation reactions, yielding gamma-emitting isotopes whose decay is measured by a scintillation detector system. By collecting gamma ray spectra over time and considering nuclear cross sections, the magnitude of the original neutron pulse is inferred.

  7. Neutron-chamber detectors and applications

    SciTech Connect

    Fehlau, P.E.; Atwater, H.F.; Coop, K.L.

    1990-01-01

    Detector applications in Nuclear Safeguards and Waste Management have included measuring neutrons from fission and (alpha,n) reactions with well-moderated neutron proportional counters, often embedded in a slab of polyethylene. Other less-moderated geometries are useful for detecting both bare and moderated fission-source neutrons with good efficiency. The neutron chamber is an undermoderated detector design comprising a large, hollow, polyethylene-walled chamber containing one or more proportional counters. Neutron-chamber detectors are relatively inexpensive; can have large apertures, usually through a thin chamber wall; and offer very good detection efficiency per dollar. Neutron-chamber detectors have also been used for monitoring vehicles and for assaying large crates of transuranic waste. Our Monte Carlo calculations for a new application (monitoring low-density waste for concealed plutonium) illustrate the advantages of the hollow-chamber design for detecting moderated fission sources. 9 refs., 6 figs., 2 tabs.

  8. Compact, energy EFFICIENT neutron source: enabling technology for various applications

    SciTech Connect

    Hershcovitch, A.; Roser, T.

    2009-12-01

    A novel neutron source comprising of a deuterium beam (energy of about 100 KeV) injected into a tube filled with tritium gas and/or tritium plasma that generates D-T fusion reactions, whose products are 14.06 MeV neutrons and 3.52 MeV alpha particles, is described. At the opposite end of the tube, the energy of deuterium ions that did not interact is recovered. Beryllium walls of proper thickness can be utilized to absorb 14 MeV neutrons and release 2-3 low energy neutrons. Each ion source and tube forms a module. Larger systems can be formed from multiple units. Unlike currently proposed methods, where accelerator-based neutron sources are very expensive, large, and require large amounts of power for operation, this neutron source is compact, inexpensive, easy to test and to scale up. Among possible applications for this neutron source concept are sub-critical nuclear breeder reactors and transmutation of radioactive waste.

  9. Out-of-field doses and neutron dose equivalents for electron beams from modern Varian and Elekta linear accelerators.

    PubMed

    Cardenas, Carlos E; Nitsch, Paige L; Kudchadker, Rajat J; Howell, Rebecca M; Kry, Stephen F

    2016-01-01

    Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels. Out-of-field dose profiles and percent depth-dose curves were measured in a Wellhofer water phantom using a Farmer ion chamber. Neutron dose was assessed using a combination of moderator buckets and gold activation foils placed on the treatment couch at various locations in the patient plane on both the Varian 21iX and Elekta Versa HD linear accelerators. Our findings showed that out-of-field electron doses were highest for the highest electron energies. These doses typically decreased with increasing distance from the field edge but showed substantial increases over some distance ranges. The Elekta linear accelerator had higher electron out-of-field doses than the Varian units examined, and the Elekta dose profiles exhibited a second dose peak about 20 to 30 cm from central-axis, which was found to be higher than typical out-of-field doses from photon beams. Electron doses decreased sharply with depth before becoming nearly constant; the dose was found to decrease to a depth of approximately E(MeV)/4 in cm. With respect to neutron dosimetry, Q values and neutron dose equivalents increased with electron beam energy. Neutron contamination from electron beams was found to be much lower than that from photon beams. Even though the neutron dose equivalent for electron beams represented a small portion of neutron doses observed under photon beams, neutron doses from electron beams may need to be considered for special cases. PMID:27455499

  10. A comparison of neutron beams for BNCT based on in-phantom neutron field assessment parameters.

    PubMed

    Woollard, J E; Albertson, B J; Reed, M K; Blue, T E; Capala, J; Gupta, N; Gahbauer, R A

    2001-02-01

    In this paper our in-phantom neutron field assessment parameters, T and DTumor, were used to evaluate several neutron sources for use in BNCT. Specifically, neutron fields from The Ohio State University (OSU) Accelerator-Based Neutron Source (ABNS) design, two alternative ABNS designs from the literature (the Al/AIF3-Al2O3 ABNS and the 7LiF-AI2O3 ABNS), a fission-convertor plate concept based on the 500-kW OSU Research Reactor (OSURR), and the Brookhaven Medical Research Reactor (BMRR) facility were evaluated. In order to facilitate a comparison of the various neutron fields, values of T and DTumor were calculated in a 14 cm x 14 cm x 14 cm lucite cube phantom located in the treatment port of each neutron source. All of the other relevant factors, such as phantom materials, kerma factors, and treatment parameters, were kept the same. The treatment times for the OSURR, the 7LiF-Al2O3 ABNS operating at a beam current of 10 mA, and the BMRR were calculated to be comparable and acceptable, with a treatment time per fraction of approximately 25 min for a four fraction treatment scheme. The treatment time per fraction for the OSU ABNS and the Al/AlF3-Al2O3 ABNS can be reduced to below 30 min per fraction for four fractions, if the proton beam current is made greater than approximately 20 mA. DTumor was calculated along the bean centerline for tumor depths in the phantom ranging from 0 to 14 cm. For tumor depths ranging from 0 to approximately 1.5 cm, the value of DTumor for the OSURR is largest, while for tumor depths ranging from 1.5 to approximately 14 cm, the value of DTumor for the OSU-ABNS is the largest. PMID:11243342

  11. 3D imaging using combined neutron-photon fan-beam tomography: A Monte Carlo study.

    PubMed

    Hartman, J; Yazdanpanah, A Pour; Barzilov, A; Regentova, E

    2016-05-01

    The application of combined neutron-photon tomography for 3D imaging is examined using MCNP5 simulations for objects of simple shapes and different materials. Two-dimensional transmission projections were simulated for fan-beam scans using 2.5MeV deuterium-deuterium and 14MeV deuterium-tritium neutron sources, and high-energy X-ray sources, such as 1MeV, 6MeV and 9MeV. Photons enable assessment of electron density and related mass density, neutrons aid in estimating the product of density and material-specific microscopic cross section- the ratio between the two provides the composition, while CT allows shape evaluation. Using a developed imaging technique, objects and their material compositions have been visualized. PMID:26953978

  12. PREFACE: IUMRS-ICA 2008 Symposium, Sessions 'X. Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science' and 'Y. Frontier of Polymeric Nano-Soft-Materials - Precision Polymer Synthesis, Self-assembling and Their Functionalization'

    NASA Astrophysics Data System (ADS)

    Takahara, Atsushi; Kawahara, Seiichi

    2009-09-01

    Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science (Symposium X of IUMRS-ICA2008) Toshiji Kanaya, Kohji Tashiro, Kazuo Sakura Keiji Tanaka, Sono Sasaki, Naoya Torikai, Moonhor Ree, Kookheon Char, Charles C Han, Atsushi Takahara This volume contains peer-reviewed invited and contributed papers that were presented in Symposium X 'Applications of Synchrotron Radiation and Neutron Beam to Soft Matter Science' at the IUMRS International Conference in Asia 2008 (IUMRS-ICA 2008), which was held on 9-13 December 2008, at Nagoya Congress Center, Nagoya, Japan. Structure analyses of soft materials based on synchrotron radiation (SR) and neutron beam have been developed steadily. Small-angle scattering and wide-angle diffraction techniques clarified the higher-order structure as well as time dependence of structure development such as crystallization and microphase-separation. On the other hand, reflectivity, grazing-incidence scattering and diffraction techniques revealed the surface and interface structural features of soft materials. From the viewpoint of strong interests on the development of SR and neutron beam techniques for soft materials, the objective of this symposium is to provide an interdisciplinary forum for the discussion of recent advances in research, development, and applications of SR and neutron beams to soft matter science. In this symposium, 21 oral papers containing 16 invited papers and 14 poster papers from China, India, Korea, Taiwan, and Japan were presented during the three-day symposium. As a result of the review of poster and oral presentations of young scientists by symposium chairs, Dr Kummetha Raghunatha Reddy (Toyota Technological Institute) received the IUMRS-ICA 2008 Young Researcher Award. We are grateful to all invited speakers and many participants for valuable contributions and active discussions. Organizing committee of Symposium (IUMRS-ICA 2008) Professor Toshiji Kanaya (Kyoto University) Professor Kohji

  13. Design of a californium-based epithermal neutron beam for neutron capture therapy.

    PubMed

    Yanch, J C; Kim, J K; Wilson, M J

    1993-08-01

    The potential of the spontaneously fissioning isotope, 252Cf, to provide epithermal neutrons for use in boron neutron capture therapy (BNCT) has been investigated using Monte Carlo simulation. The Monte Carlo code MCNP was used to design an assembly composed of a 26 cm long, 11 cm radius cylindrical D2O moderator followed by a 64 cm long Al filter. Lithium filters are placed between the moderator and the filter and between the Al and the patient. A reflector surrounding the moderator/filter assembly is required in order to maintain adequate therapy flux at the patient position. An ellipsoidal phantom composed of skull- and brain-equivalent material was used to determine the dosimetric effect of this beam. It was found that both advantage depths and advantage ratios compare very favourably with reactor and accelerator epithermal neutron sources. The dose rate obtainable, on the other hand, is 4.1 RBE cGy min-1, based on a very large (1.0 g) source of 252Cf. This dose rate is two to five times lower than those provided by existing reactor beams and can be viewed as a drawback of using 252Cf as a neutron source. Radioisotope sources, however, do offer the advantage of in-hospital installation.

  14. Mixed field dosimetry of epithermal neutron beams for boron neutron capture therapy at the MITR-II research reactor.

    PubMed

    Rogus, R D; Harling, O K; Yanch, J C

    1994-10-01

    During the past several years, there has been growing interest in Boron Neutron Capture Therapy (BNCT) using epithermal neutron beams. The dosimetry of these beams is challenging. The incident beam is comprised mostly of epithermal neutrons, but there is some contamination from photons and fast neutrons. Within the patient, the neutron spectrum changes rapidly as the incident epithermal neutrons scatter and thermalize, and a photon field is generated from neutron capture in hydrogen. In this paper, a method to determine the doses from thermal and fast neutrons, photons, and the B-10(n, alpha)Li-7 reaction is presented. The photon and fast neutron doses are measured with ionization chambers, in realistic phantoms, using the dual chamber technique. The thermal neutron flux is measured with gold foils using the cadmium difference technique, the thermal neutron and B-10 doses are determined by the kerma factor method. Representative results are presented for a unilateral irradiation of the head. Sources of error in the method as applied to BNCT dosimetry, and the uncertainties in the calculated doses are discussed.

  15. Physics data base for the Beam Plasma Neutron Source (BPNS)

    NASA Astrophysics Data System (ADS)

    Coensgen, F. H.; Casper, T. A.; Correll, D. L.; Damm, C. C.; Futch, A. H.; Molvik, A. W.

    1990-10-01

    A 14-MeV deuterium-tritium (D-T) neutron source for accelerated end-of-life testing of fusion reactor materials has been designed on the basis of a linear two-component collisional plasma system. An intense flux (up to 5 x 10(exp 18)/sq m sec) of 14 MeV neutrons is produced in a fully ionized high-density (n sub e approx. = 3 x 10(exp 21) per cu m) tritium target by transverse injection of 60 MW of neutral beam power. Power deposited in the target is removed by thermal electron conduction to large end chambers, where it is deposited in gaseous plasma collectors. We show in this paper that the major physics issues have now been experimentally demonstrated. These include magnetohydrodynamic (MHD) equilibrium and stability, microstability, startup, fueling, Spitzer electron thermal conductivity, and power deposition in a gaseous plasma collector. However, an integrated system was not demonstrated.

  16. Compact D-D/D-T neutron generators and their applications

    SciTech Connect

    Lou, Tak Pui

    2003-05-01

    Neutron generators based on the {sup 2}H(d,n){sup 3}He and {sup 3}H(d,n){sup 4}He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >10{sup 9} n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 10{sup 14} n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 10{sup 5} n/cm{sup 2}s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and Boron Neutron Capture Therapy (BNCT). The

  17. Compact D-D/D-T neutron generators and their applications

    NASA Astrophysics Data System (ADS)

    Lou, Tak Pui

    2003-10-01

    Neutron generators based on the 2H(d,n)3He and 3H(d,n)4He fusion reactions are the most commonly available neutron sources. The applications of current commercial neutron generators are often limited by their low neutron yield and their short operational lifetime. A new generation of D-D/D-T fusion-based neutron generators has been designed at Lawrence Berkeley National Laboratory (LBNL) by using high current ion beams hitting on a self-loading target that has a large surface area to dissipate the heat load. This thesis describes the rationale behind the new designs and their potential applications. A survey of other neutron sources is presented to show their advantages and disadvantages compared to the fusion-based neutron generator. A prototype neutron facility was built at LBNL to test these neutron generators. High current ion beams were extracted from an RF-driven ion source to produce neutrons. With an average deuteron beam current of 24 mA and an energy of 100 keV, a neutron yield of >109 n/s has been obtained with a D-D coaxial neutron source. Several potential applications were investigated by using computer simulations. The computer code used for simulations and the variance reduction techniques employed were discussed. A study was carried out to determine the neutron flux and resolution of a D-T neutron source in thermal neutron scattering applications for condensed matter experiments. An error analysis was performed to validate the scheme used to predict the resolution. With a D-T neutron yield of 1014 n/s, the thermal neutron flux at the sample was predicted to be 7.3 x 105 n/cm2s. It was found that the resolution of cold neutrons was better than that of thermal neutrons when the duty factor is high. This neutron generator could be efficiently used for research and educational purposes at universities. Additional applications studied were positron production and Boron Neutron Capture Therapy (BNCT). The neutron flux required for positron production

  18. Radioactive ion beams produced by neutron-induced fission at ISOLDE

    NASA Astrophysics Data System (ADS)

    Catherall, R.; Lettry, J.; Gilardoni, S.; Köster, U.; Isolde Collaboration

    2003-05-01

    The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL [EU-RTD Project EURISOL (HPRI-CT-1999-50001)] are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN [E. Kugler, Hyperfine Interact. 129 (2000) 23], tests have been made on standard ISOLDE actinide targets using fast-neutron bunches produced by bombarding thick, high- Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC 2/graphite and ThO 2 targets with tungsten and tantalum converters, are presented. To gain further knowledge for the design of a dedicated target as required by the TARGISOL project [EU-RTD Project TARGISOL (HPRI-CT-2001-50033)], the results are compared to simulations, using the MARS [N.V. Mokhov, S.I. Striganov, A. Van Ginneken, S.G. Mashnik, A.J. Sierk, J. Ranft, MARS code developments, in: 4th Workshop on Simulating Accelerator Radiation Environments, SARE-4, Knoxville, USA, 14-15.9.1998, FERMILAB-PUB-98-379, nucl-th/9812038; N.V. Mokhov, The Mars Code System User's Guide, Fermilab-FN-628, 1995; N.V. Mokhov, MARS Code Developments, Benchmarking and Applications, Fermilab-Conf-00-066, 2000; O.E. Krivosheev, N.V. Mokhov, A New MARS and its Applications, Fermilab-Conf-98/43, 1998] code interfaced with MCNP [J.S. Hendrics, MCNP4C LANL Memo X-5; JSH-2000-3; J.F. Briemesteir (Ed.), MCNP - A General Montecarlo N

  19. Radioactive ion beams produced by neutron-induced fission at ISOLDE

    NASA Astrophysics Data System (ADS)

    Isolde Collaboration; Catherall, R.; Lettry, J.; Gilardoni, S.; Köster, U.

    2003-05-01

    The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL [EU-RTD Project EURISOL (HPRI-CT-1999-50001)] are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN [E. Kugler, Hyperfine Interact. 129 (2000) 23], tests have been made on standard ISOLDE actinide targets using fast-neutron bunches produced by bombarding thick, high-/Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten and tantalum converters, are presented. To gain further knowledge for the design of a dedicated target as required by the TARGISOL project [EU-RTD Project TARGISOL (HPRI-CT-2001-50033)], the results are compared to simulations, using the MARS [N.V. Mokhov, S.I. Striganov, A. Van Ginneken, S.G. Mashnik, A.J. Sierk, J. Ranft, MARS code developments, in: 4th Workshop on Simulating Accelerator Radiation Environments, SARE-4, Knoxville, USA, 14-15.9.1998, FERMILAB-PUB-98-379, nucl-th/9812038; N.V. Mokhov, The Mars Code System User's Guide, Fermilab-FN-628, 1995; N.V. Mokhov, MARS Code Developments, Benchmarking and Applications, Fermilab-Conf-00-066, 2000; O.E. Krivosheev, N.V. Mokhov, A New MARS and its Applications, Fermilab-Conf-98/43, 1998] code interfaced with MCNP [J.S. Hendrics, MCNP4C LANL Memo X-5; JSH-2000-3; J.F. Briemesteir (Ed.), MCNP - A General Montecarlo N

  20. Silicon detectors for monitoring neutron beams in n-TOF beamlines

    SciTech Connect

    Cosentino, L.; Pappalardo, A.; Piscopo, M.; Finocchiaro, P.; Musumarra, A.; Barbagallo, M.; Colonna, N.; Damone, L.

    2015-07-15

    During 2014, the second experimental area (EAR2) was completed at the n-TOF neutron beam facility at CERN (n-TOF indicates neutron beam measurements by means of time of flight technique). The neutrons are produced via spallation, by means of a high-intensity 20 GeV pulsed proton beam impinging on a thick target. The resulting neutron beam covers the energy range from thermal to several GeV. In this paper, we describe two beam diagnostic devices, both exploiting silicon detectors coupled with neutron converter foils containing {sup 6}Li. The first one is based on four silicon pads and allows monitoring of the neutron beam flux as a function of the neutron energy. The second one, in beam and based on position sensitive silicon detectors, is intended for the reconstruction of the beam profile, again as a function of the neutron energy. Several electronic setups have been explored in order to overcome the issues related to the gamma flash, namely, a huge pulse present at the start of each neutron bunch which may blind the detectors for some time. The two devices were characterized with radioactive sources and also tested at the n-TOF facility at CERN. The wide energy and intensity range they proved capable of sustaining made them attractive and suitable to be used in both EAR1 and EAR2 n-TOF experimental areas, where they became immediately operational.

  1. UCN sources at external beams of thermal neutrons. An example of PIK reactor

    NASA Astrophysics Data System (ADS)

    Lychagin, E. V.; Mityukhlyaev, V. A.; Muzychka, A. Yu.; Nekhaev, G. V.; Nesvizhevsky, V. V.; Onegin, M. S.; Sharapov, E. I.; Strelkov, A. V.

    2016-07-01

    We consider ultracold neutron (UCN) sources based on a new method of UCN production in superfluid helium (4He). The PIK reactor is chosen as a perspective example of application of this idea, which consists of installing 4He UCN source in the beam of thermal or cold neutrons and surrounding the source with moderator-reflector, which plays the role of cold neutron (CN) source feeding the UCN source. CN flux in the source can be several times larger than the incident flux, due to multiple neutron reflections from the moderator-reflector. We show that such a source at the PIK reactor would provide an order of magnitude larger density and production rate than an analogous source at the ILL reactor. We estimate parameters of 4He source with solid methane (CH4) or/and liquid deuterium (D2) moderator-reflector. We show that such a source with CH4 moderator-reflector at the PIK reactor would provide the UCN density of ~1·105 cm-3, and the UCN production rate of ~2·107 s-1. These values are respectively 1000 and 20 times larger than those for the most intense UCN user source. The UCN density in a source with D2 moderator-reflector would reach the value of ~2·105 cm-3, and the UCN production rate would be equal ~8·107 s-1. Installation of such a source in a beam of CNs would slightly increase the density and production rate.

  2. Femtosecond Beam Sources and Applications

    NASA Astrophysics Data System (ADS)

    Uesaka, Mitsuru

    2004-12-01

    Short particle beam science has been promoted by electron linac and radiation chemistry up to picoseconds. Recently, table-top TW laser enables several kinds of short particle beams and pump-and-probe analyses. 4th generation SR sources aim to generation and application of about 100 fs X-ray. Thus, femtosecond beam science has become one of the important field in advanced accelerator concepts. By using electron linac with photoinjector, about 200 fs single bunch and 3 fs multi-bunches are available. Tens femtoseconds monoenergetic electron bunch is expected by laser plasma cathode. Concerning the electron bunch diagnosis, we have seen remarkable progress in streak camera, coherent radiation spectroscopy, fluctuation method and E/O crystal method. Picosecond time-resolved pump-and-probe analysis by synchronizing electron linac and laser is now possible, but the timing jitter and drift due to several fluctuations in electronic devices and environment are still in picoseconds. On the other hand, the synchronization between laser and secondary beam is done passively by an optical beam-splitter in the system based on one TW laser. Therefore, the timing jitter and drift do not intrinsically exist there. The author believes that the femtosecond time-resolved pump-and-probe analysis must be initiated by the laser plasma beam sources. As to the applications, picosecond time-resolved system by electron photoinjector/linac and femtosecond laser are operating in more than 5 facilities for radiation chemistry in the world. Ti:Sapphire-laser-based repetitive pump-and-probe analysis started by time-resolved X-ray diffraction to visualize the atomic motion. Nd:Glass-laser-based single-shot analysis was performed to visualize the laser ablation via the single-shot ion imaging. The author expects that protein dynamics and ultrafast nuclear physics would be the next interesting targets. Monograph titled "Femtosecond Beam Science" is published by Imperial College Press

  3. Neutron beam irradiation study of workload dependence of SER in a microprocessor

    SciTech Connect

    Michalak, Sarah E; Graves, Todd L; Hong, Ted; Ackaret, Jerry; Sonny, Rao; Subhasish, Mitra; Pia, Sanda

    2009-01-01

    It is known that workloads are an important factor in soft error rates (SER), but it is proving difficult to find differentiating workloads for microprocessors. We have performed neutron beam irradiation studies of a commercial microprocessor under a wide variety of workload conditions from idle, performing no operations, to very busy workloads resembling real HPC, graphics, and business applications. There is evidence that the mean times to first indication of failure, MTFIF defined in Section II, may be different for some of the applications.

  4. Polarized neutrons and their applications

    SciTech Connect

    Moon, R.; Endoh, Y.; Felcher, G.; Majkrzak, C.; Mezei, F.; Pynn, R.; Shirane, G.

    1985-01-01

    The role of polarized neutrons in the study of magnetic and nonmagnetic materials is discussed. magnetic structure, spin density, nuclear magnetism and spin dynamics are listed as magnetic properties which may be accessed by polarized neutrons. Low dimensional magnets, disordered magnetic systems, surface magnetism are discussed as well as topography and depolarization. Polarization techniques are discussed for both study state and pulsed modes. 4 refs. (WRF)

  5. Industrial applications of neutron diffraction

    SciTech Connect

    Felcher, G.P.

    1989-01-01

    Neutron diffraction (or, to be more general, neutron scattering) is a most versatile and universal tool, which has been widely employed to probe the structure, the dynamics and the magnetism of condensed matter. Traditionally used for fundamental research in solid state physics, this technique more recently has been applied to problems of immediate industrial interest, as illustrated in examples covering the main fields of endeavour. 14 refs., 14 figs.

  6. Prediction of In-Phantom Dose Distribution Using In-Air Neutron Beam Characteristics for Boron Neutron Capture Synovectomy

    SciTech Connect

    Verbeke, Jerome M.; Chen, Allen S.; Vujic, Jasmina L.; Leung, Ka-Ngo

    2000-08-15

    A monoenergetic neutron beam simulation study was carried out to determine the optimal neutron energy range for treatment of rheumatoid arthritis using radiation synovectomy. The goal of the treatment is the ablation of diseased synovial membranes in joints such as knees and fingers. This study focuses on human knee joints. Two figures of merit are used to measure the neutron beam quality, the ratio of the synovium-absorbed dose to the skin-absorbed dose, and the ratio of the synovium-absorbed dose to the bone-absorbed dose. It was found that (a) thermal neutron beams are optimal for treatment and that (b) similar absorbed dose rates and therapeutic ratios are obtained with monodirectional and isotropic neutron beams. Computation of the dose distribution in a human knee requires the simulation of particle transport from the neutron source to the knee phantom through the moderator. A method was developed to predict the dose distribution in a knee phantom from any neutron and photon beam spectra incident on the knee. This method was revealed to be reasonably accurate and enabled one to reduce the particle transport simulation time by a factor of 10 by modeling the moderator only.

  7. Neutron beam measurement of industrial polymer materials for composition and bulk integrity

    NASA Astrophysics Data System (ADS)

    Rogante, M.; Rosta, L.; Heaton, M. E.

    2013-10-01

    Neutron beam techniques, among other non-destructive diagnostics, are particularly irreplaceable in the complete analysis of industrial materials and components when supplying fundamental information. In this paper, nanoscale small-angle neutron scattering analysis and prompt gamma activation analysis for the characterization of industrial polymers are considered. The basic theoretical aspects are briefly introduced and some applications are presented. The investigations of the SU-8 polymer in axial airflow microturbines—i.e. microelectromechanical systems—are presented foremost. Also presented are full and feasibility studies on polyurethanes, composites based on cross-linked polymers reinforced by carbon fibres and polymer cement concrete. The obtained results have provided a substantial contribution to the improvement of the considered materials, and indeed confirmed the industrial applicability of the adopted techniques in the analysis of polymers.

  8. Spatial response characterization of liquid scintillator detectors using collimated gamma-ray and neutron beams

    NASA Astrophysics Data System (ADS)

    Naeem, S. F.; Clarke, S. D.; Pozzi, S. A.

    2013-10-01

    Liquid scintillators are suitable for many applications because they can detect and characterize fast neutrons as well as gamma-rays. This paper presents the response of a 15-cm-in-length×15-cm-in-height×8.2-cm-in-width EJ-309 liquid scintillator with respect to the position of neutron and gamma-ray interactions. Liquid scintillator cells are typically filled with 97% of the scintillating cocktail to address thermal expansion of the liquid in varying temperature conditions. Measurements were taken with collimated 137Cs and 252Cf sources for gamma-ray and neutron mapping of the detector, respectively. MCNPX-PoliMi (ver. 2.0) simulations were also performed to demonstrate the spatial response of the detector. Results show that the detector response is greatest at the center and decreases when the collimated neutron and gamma-ray beam is moved toward the edge of the detector. The measured response in the voxels surrounding the detector center decreased by approximately 6% and 12% for gamma-ray and neutron scans, respectively, when compared to the center voxel. The measured decrease in the detector response was most pronounced at the corners of detector assembly. For the corner voxels located in the bottom row of the detector, the measured response decreased by approximately 39% for both gamma-ray and neutron scans. For the corner voxels located in the top row of the detector, the measured response decreased by approximately 66% and 48% for gamma-ray and neutron scans, respectively. Both measurements and simulations show the inefficient production of secondary charged particles in the voxels located in the top portion of the detector due to the presence of expansion volume. Furthermore, the presence of the expansion volume potentially affects the transport of the scintillation light through the coupling window between the liquid scintillator and the photocathode in the photomultiplier tube.

  9. Results of the first beam time with the neutron decay spectrometer aSPECT

    NASA Astrophysics Data System (ADS)

    Baeßler, Stefan; Ayala Guardia, Fidel; Borg, Michael; Eberhardt, Klaus; Heil, Werner; Konrad, Gertrud; Muñoz Horta, Raquel; Sobolev, Yuri; Konorov, Igor; Petzoldt, Gerd; Simson, Martin; Zimmer, Oliver; Glück, Ferenc; Rich, Dennis

    2007-10-01

    With the neutron decay spectrometer aSPECT we aim to measure the proton spectrum in free neutron beta decay precisely. This allows us to determine the neutrino electron correlation coefficient a. We had our first test beam time in 2005/06 at the new neutron source FRM-II in Garching. In my talk I want to talk about the results, the systematic effects we found and the ways how to deal with them in later beam times.

  10. Design of neutron beams at the Argonne Continuous Wave Linac (ACWL) for boron neutron capture therapy and neutron radiography

    SciTech Connect

    Zhou, X.L.; McMichael, G.E.

    1994-10-01

    Neutron beams are designed for capture therapy based on p-Li and p-Sc reactions using the Argonne Continuous Wave Linac (ACWL). The p-Li beam will provide a 2.5 {times} 10{sup 9} n/cm{sup 2}s epithermal flux with 7 {times} 10{sup 5} {gamma}/cm{sup 2}s contamination. On a human brain phantom, this beam allows an advantage depth (AD) of 10 cm, an advantage depth dose rate (ADDR) of 78 cGy/min and an advantage ratio (AR) of 3.2. The p-Sc beam offers 5.9 {times} 10{sup 7} n/cm{sup 2}s and a dose performance of AD = 8 cm and AR = 3.5, suggesting the potential of near-threshold (p,n) reactions such as the p-Li reaction at E{sub p} = 1.92 MeV. A thermal radiography beam could also be obtained from ACWL.

  11. Upgrades of the epithermal neutron beam at the Brookhaven Medical Research Reactor

    SciTech Connect

    Liu, Hungyuan B.; Brugger, R.M.; Rorer, D.C.

    1994-12-31

    The first epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR) was installed in 1988 and produced a neutron beam that was satisfactory for the development of NCT with epithermal neutrons. This beam was used routinely until 1992 when the beam was upgraded by rearranging fuel elements in the reactor core to achieve a 50% increase in usable flux. Next, after computer modeling studies, it was proposed that the Al and Al{sub 2}O{sub 3} moderator material in the shutter that produced the epithermal neutrons could be rearranged to enhance the beam further. However, this modification was not started because a better option appeared, namely to use fission plates to move the source of fission neutrons closer to the moderator and the patient irradiation position to achieve more efficient moderation and production of epithermal neutrons. A fission plate converter (FPC) source has been designed recently and, to test the concept, implementation of this upgrade has started. The predicted beam parameters will be 12 x 10{sup 9} n{sub epi}/cm{sup 2}sec accompanying with doses from fast neutrons and gamma rays per epithermal neutron of 2.8 x 10{sup -11} and < 1 x 10{sup -11} cGycm{sup 2}/n, respectively, and a current-to-flux ratio of epithermal neutrons of 0.78. This conversion could be completed by late 1996.

  12. Neutron collimator for neutron radiography applications at tangential port of the TRIGA RC-1 reactor

    NASA Astrophysics Data System (ADS)

    Rosa, R.; Andreoli, F.; Mattoni, M.; Palomba, M.

    2009-06-01

    At the ENEA TRIGA research reactor (Casaccia Research Center, Rome) a new neutron collimator has been designed and installed at the neutron tangential channel. This collimator, that is part of a neutron/X-ray facility for NDT analysis, was experimentally characterized and optimized in terms of thermal neutron fluence rate, spatial/energetic distribution, photon air KERMA and effective beam diameter. This paper shows the methodologies and the results of the experimental analysis that were carried out.

  13. Working group session report: Neutron beam line shielding.

    SciTech Connect

    Russell, G. J.; Ikedo, Y.

    2001-01-01

    We have examined the differences between a 2-D model and a 3-D model for designing the beam-line shield for the HIPPO instrument at the Lujan Center at the Los Alamos National Laboratory. We have calculated the total (neutron and gamma ray) dose equivalent rate coming out of the personal access ports from the HIPPO instrument experiment cave. In order to answer this question, we have investigated two possible worst-case scenarios: (a) failure of the T{sub 0}-chopper and no sample at the sample position; and (b) failure of the T{sub 0}-chopper with a thick sample (a piece of Inconel-718, 10 cm diam by 30 cm long) at the sample position.

  14. SU-E-T-542: Measurement of Internal Neutrons for Uniform Scanning Proton Beams

    SciTech Connect

    Islam, M; Ahmad, S; Zheng, Y; Rana, S; Collums, T; Monsoon, J; Benton, E

    2015-06-15

    Purpose: In proton radiotherapy, the production of neutrons is a wellknown problem since neutron exposure can lead to increased risk of secondary cancers later in the patient’s lifetime. The assessment of neutron exposure is, therefore, important for the overall quality of proton radiotherapy. This study investigates the secondary neutrons created inside the patient from uniform scanning proton beams. Methods: Dose equivalent due to secondary neutrons was measured outside the primary field as a function of distance from beam isocenter at three different angles, 45, 90 and 135 degree, relative to beam axis. Plastic track nuclear detector (CR-39 PNTD) was used for the measurement of neutron dose. Two experimental configurations, in-air and cylindrical-phantom, were designed. In a cylindrical-phantom configuration, a cylindrical phantom of 5.5 cm diameter and 35 cm long was placed along the beam direction and in an in-air configuration, no phantom was used. All the detectors were placed at nearly identical locations in both configurations. Three proton beams of range 5 cm, 18 cm, and 32 cm with 4 cm modulation width and a 5 cm diameter aperture were used. The contribution from internal neutrons was estimated from the differences in measured dose equivalent between in-air and cylindrical-phantom configurations at respective locations. Results: The measured ratio of neutron dose equivalent to the primary proton dose (H/D) dropped off with distance and ranged from 27 to 0.3 mSv/Gy. The contribution of internal neutrons near the treatment field edge was found to be up to 64 % of the total neutron exposure. As the distance from the field edge became larger, the external neutrons from the nozzle appear to dominate and the internal neutrons became less prominent. Conclusion: This study suggests that the contribution of internal neutrons could be significant to the total neutron dose equivalent.

  15. Neutron energy measurements in emergency response applications

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sanjoy; Guss, Paul; Hornish, Michael; Wilde, Scott; Stampahar, Tom; Reed, Michael

    2009-08-01

    We present significant results in recent advances in the measurement of neutron energy. Neutron energy measurements are a small but significant part of radiological emergency response applications. Mission critical information can be obtained by analyzing the neutron energy given off from radioactive materials. In the case of searching for special nuclear materials, neutron energy information from an unknown source can be of importance. At the Remote Sensing Laboratory (RSL) of National Security Technologies, LLC, a series of materials, viz., liquid organic scintillator (LOS), Lithium Gadolinium Borate (LGB) or Li6Gd(BO3)3 in a plastic matrix, a recently developed crystal of Cesium Lithium Yttrium Chloride, Cs2LiYCl6: Ce (called CLYC)[1], and normal plastic scintillator (BC-408) with 3He tubes have been used to study their effectiveness as a portable neutron energy spectrometer. Comparisons illustrating the strengths of the various materials will be provided. Of these materials, LGB offers the ability to tailor its response to the neutron spectrum by varying the isotopic composition of the key constituents (Lithium, Gadolinium [Yttrium], and Boron). All three of the constituent elements possess large neutron capture cross section isotopes for highly exothermic reactions. These compounds of composition Li6Gd(Y)(BO3)3 can be activated by Cerium ions Ce3+. CLYC, on the other hand, has a remarkable gamma response in addition to superb neutron discrimination, comparable to that of Europium-doped Lithium Iodide (6LiI: Eu). Comparing these two materials, CLYC has higher light output (4500 phe/MeV) than that from 6LiI: Eu and shows better energy resolution for both gamma and neutron pulse heights. Using CLYC, gamma energy pulses can be discriminated from the neutron signals by simple pulse height separation. For the cases of both LGB and LOS, careful pulse shape discrimination is needed to separate the gamma energy signals from neutron pulses. Both analog and digital

  16. A compact neutron beam generator system designed for prompt gamma nuclear activation analysis.

    PubMed

    Ghassoun, J; Mostacci, D

    2011-08-01

    In this work a compact system was designed for bulk sample analysis using the technique of PGNAA. The system consists of (252)Cf fission neutron source, a moderator/reflector/filter assembly, and a suitable enclosure to delimit the resulting neutron beam. The moderator/reflector/filter arrangement has been optimised to maximise the thermal neutron component useful for samples analysis with a suitably low level of beam contamination. The neutron beam delivered by this compact system is used to irradiate the sample and the prompt gamma rays produced by neutron reactions within the sample elements are detected by appropriate gamma rays detector. Neutron and gamma rays transport calculations have been performed using the Monte Carlo N-Particle transport code (MCNP5).

  17. Generation and detection of neutron beams with orbital angular momentum

    NASA Astrophysics Data System (ADS)

    Pushin, Dmitry A.; Barankov, Roman A.; Clark, Charles W.; Huber, Michael G.; Arif, Muhammad; Cory, David G.

    2015-05-01

    Orbital angular momentum (OAM) states of light, in which photons carry lℏ units of angular momentum along their direction of propagation, are of interest in a variety of applications. The Schrödinger equation for massive particles also supports OAM solutions, and OAM states have been demonstrated with ultracold atoms and electrons. Here we report the first generation and detection of OAM states of neutrons, with l up to 7. These are made using spiral phase plates (SPP), milled out of 6061 aluminum alloy dowels with a high-resolution computer-controlled milling machine. When a SPP is placed in one arm of a Mach-Zehnder neutron interferometer, the interferogram reveals the characteristic patterns of OAM states. Addition of angular momenta is effected by concatenation of SPPs with different values of l; we have found the experimental result 1 + 2 = 3 , in reasonable agreement with theory. The advent of OAM provides an additional, quantized, degree of freedom to neutron interferometry, enlarging the qubit structure available for tests of quantum information processing and foundations of quantum physics.

  18. Dysprosium detector for neutron dosimetry in external beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Ostinelli, A.; Berlusconi, C.; Conti, V.; Duchini, M.; Gelosa, S.; Guallini, F.; Vallazza, E.; Prest, M.

    2014-09-01

    Radiotherapy treatments with high-energy (>8 MeV) photon beams are a standard procedure in clinical practice, given the skin and near-target volumes sparing effect, the accurate penetration and the uniform spatial dose distribution. On the other hand, despite these advantages, neutrons may be produced via the photo-nuclear (γ,n) reactions of the high-energy photons with the high-Z materials in the accelerator head, in the treatment room and in the patient, resulting in an unwanted dose contribution which is of concern, given its potential to induce secondary cancers, and which has to be monitored. This work presents the design and the test of a portable Dysprosium dosimeter to be used during clinical treatments to estimate the "in vivo" dose to the patient. The dosimeter has been characterized and validated with tissue-equivalent phantom studies with a Varian Clinical iX 18 MV photon beam, before using it with a group of patients treated at the S. Anna Hospital in Como. The working principle of the dosimeter together with the readout chain and the results in terms of delivered dose are presented.

  19. A Kinematically Beamed, Low Energy Pulsed Neutron Source for Active Interrogation

    SciTech Connect

    Dietrich, D; Hagmann, C; Kerr, P; Nakae, L; Rowland, M; Snyderman, N; Stoeffl, W; Hamm, R

    2004-10-07

    We are developing a new active interrogation system based on a kinematically focused low energy neutron beam. The key idea is that one of the defining characteristics of SNM (Special Nuclear Materials) is the ability for low energy or thermal neutrons to induce fission. Thus by using low energy neutrons for the interrogation source we can accomplish three goals, (1) Energy discrimination allows us to measure the prompt fast fission neutrons produced while the interrogation beam is on; (2) Neutrons with an energy of approximately 60 to 100 keV do not fission 238U and Thorium, but penetrate bulk material nearly as far as high energy neutrons do and (3) below about 100keV neutrons lose their energy by kinematical collisions rather than via the nuclear (n,2n) or (n,n') processes thus further simplifying the prompt neutron induced background. 60 keV neutrons create a low radiation dose and readily thermal capture in normal materials, thus providing a clean spectroscopic signature of the intervening materials. The kinematically beamed source also eliminates the need for heavy backward and sideway neutron shielding. We have designed and built a very compact pulsed neutron source, based on an RFQ proton accelerator and a lithium target. We are developing fast neutron detectors that are nearly insensitive to the ever-present thermal neutron and neutron capture induced gamma ray background. The detection of only a few high energy fission neutrons in time correlation with the linac pulse will be a clear indication of the presence of SNM.

  20. Fast and thermal neutron profiles for a 25-MV x-ray beam.

    PubMed

    Price, K W; Nath, R; Holeman, G R

    1978-01-01

    High-energy x-ray radiotherapy machines generate neutrons by photonuclear reactions in the target and the treatment head and expose the patient to a neutron flux. In order to evaluate the neutron exposure quantitatively, fast and thermal neutron profiles for 25-MV x-ray beams of the Sagittaire accelerator have been measured. An activation technique, using the reactions 31P(n, gamma)32P (thermal neutrons) and 31P(n, p)31Si (fast neutrons, E greater than 0.7 MeV), has been developed to measure fast- and thermal-neutron fluxes in an intense high-energy photon flux. The sensitivity of this activation detector to high-energy photons, which has plagued many previous neutron measurements, was carefully measured and found to be less than 4%. Neutron fluxes for various photon field sizes ranging from 5 X 5 cm to 30 X 30 cm have been measured. The fast-neutron profiles were observed to have rounded edges and the thermal fluxes were found to be relatively uniform. In the central part of the x-ray beam, the ratio of neutron dose equivalent to photon absorbed dose was found to be between 0.2% and 0.5%. Outside of the photon field, the ratio of neutron dose equivalent to the central-axis photon absorbed dose was 0.12%.

  1. Compact, Energy Self-Sustaining Neutron Source: Enabling Technology for Various Applications

    NASA Astrophysics Data System (ADS)

    Hershcovitch, Ady; Horak, W.; Johnson, B.; Todosow, M.; Roser, T.; Driscoll, M.

    2008-11-01

    In this novel neutron source, a deuterium beam (energy of about 100 keV) is to be injected through a Plasma Window into a tube filled with tritium gas or tritium plasma to generate D-T fusion reactions whose products are 14.06 MeV neutrons and 3.52 MeV alpha particles. At the opposite end of the tube, the energy of deuterium ions that did not interact is recovered. Energy recovery is close to 100%. Mo and Nb walls of proper thickness will absorb 14 MeV neutrons and release 2 -- 3 low energy neutrons. Each ion source and tube forms a module. Larger systems can be formed from multiple units. Beam propagation can be further enhanced with vortex stabilized discharges, electron beams in opposite direction (with energy recovery) or magnetic fields where possible. Unlike current methods, where accelerator based neutron sources require large amounts of power for operation, this neutron source will generated enough power to compensate for the power required to generate the ion beam. Concept description and basic calculation will be presented. Among possible applications for this neutron source concept are sub-critical nuclear breeder reactors and accelerator transmutation of radioactive waste.

  2. Characterization of pulsed (plasma focus) neutron source with image plate and application to neutron radiography

    SciTech Connect

    Andola, Sanjay; Niranjan, Ram; Rout, R. K.; Kaushik, T. C.; Gupta, S. C.; Shaikh, A. M.

    2013-02-05

    Plasma focus device of Mather type developed in house has been used first time for neutron radiography of different objects. The device gives (1.2{+-}0.3) Multiplication-Sign 10{sup 9} neutrons per pulse produced by D-D fusion reaction with a pulse width of 50{+-}5 ns. The method involves exposing sample to be radiographed to thermalized D-D neutrons and recording the image on Fuji-film BAS-ND image plates. The thermal neutron component of the moderated beam was estimated using two image plates: a conventional IP for X-rays and gamma rays, and an IP doped with Gd for detecting neutrons.

  3. Polymer gel dosimetry for neutron beam in the Neutron Exposure Accelerator System for Biological Effect Experiments (NASBEE)

    NASA Astrophysics Data System (ADS)

    Kawamura, H.; Sato, H.; Hamano, T.; Suda, M.; Yoshii, H.

    2015-01-01

    This study aimed to investigate whether gel dosimetry could be used to measure neutron beams. We irradiated a BANG3-type polymer gel dosimeter using neutron beams in the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) at the National Institute of Radiological Sciences (NIRS) in Japan. First, the polymer gels were irradiated from 0 to 7.0 Gy to investigate the dose-R2 responses. Irradiated gels were evaluated using 1.5-T magnetic resonance R2 images. Second, the polymer gels were irradiated to 1.0, 3.0, and 5.0 Gy to acquire a depth-R2 response curve. The dose-R2 response curve was linear up to approximately 7 Gy, with a slope of 1.25 Gy-1·s-1. Additionally, compared with the photon- irradiated gels, the neutron-irradiated gels had lower R2 values. The acquired depth-R2 curves of the central axis from the 3.0- and 5.0-Gy neutron dose-irradiated gels exhibited an initial build-up. Although, a detailed investigation is needed, polymer gel dosimetry is effective for measuring the dose-related R2 linearity and depth-R2 relationships of neutron beams.

  4. The ion beam sputtering facility at KURRI: Coatings for advanced neutron optical devices

    NASA Astrophysics Data System (ADS)

    Hino, Masahiro; Oda, Tatsuro; Kitaguchi, Masaaki; Yamada, Norifumi L.; Tasaki, Seiji; Kawabata, Yuji

    2015-10-01

    We describe a film coating facility for the development of multilayer mirrors for use in neutron optical devices that handle slow neutron beams. Recently, we succeeded in fabricating a large neutron supermirror with high reflectivity using an ion beam sputtering system (KUR-IBS), as well as all neutron supermirrors in two neutron guide tubes at BL06 at J-PARC/MLF. We also realized a large flexible self-standing m=5 NiC/Ti supermirror and very small d-spacing (d=1.65 nm) multilayer sheets. In this paper, we present an overview of the performance and utility of non-magnetic neutron multilayer mirrors fabricated with the KUR-IBS

  5. Measuring the free neutron lifetime to <= 0.3s via the beam method

    NASA Astrophysics Data System (ADS)

    Mulholland, Jonathan; Fomin, Nadia; BL3 Collaboration

    2015-10-01

    Neutron beta decay is an archetype for all semi-leptonic charged-current weak processes. A precise value for the neutron lifetime is required for consistency tests of the Standard Model and is needed to predict the primordial 4He abundance from the theory of Big Bang Nucleosynthesis. An effort has begun for an in-beam measurement of the neutron lifetime with an projected <=0.3s uncertainty. This effort is part of a phased campaign of neutron lifetime measurements based at the NIST Center for Neutron Research, using the Sussex-ILL-NIST technique. Recent advances in neutron fluence measurement techniques as well as new large area silicon detector technology address the two largest sources of uncertainty of in-beam measurements, paving the way for a new measurement. The experimental design and projected uncertainties for the 0.3s measurement will be discussed.

  6. Measuring the free neutron lifetime to <= 0.3s via the beam method

    NASA Astrophysics Data System (ADS)

    Fomin, Nadia; Mulholland, Jonathan

    2015-04-01

    Neutron beta decay is an archetype for all semi-leptonic charged-current weak processes. A precise value for the neutron lifetime is required for consistency tests of the Standard Model and is needed to predict the primordial 4 He abundance from the theory of Big Bang Nucleosynthesis. An effort has begun for an in-beam measurement of the neutron lifetime with an projected <=0.3s uncertainty. This effort is part of a phased campaign of neutron lifetime measurements based at the NIST Center for Neutron Research, using the Sussex-ILL-NIST technique. Recent advances in neutron fluence measurement techniques as well as new large area silicon detector technology address the two largest sources of uncertainty of in-beam measurements, paving the way for a new measurement. The experimental design and projected uncertainties for the 0.3s measurement will be discussed. This work is supported by the DOE office of Science, NIST and NSF.

  7. Critical beam dynamical issues in neutron spallation sources

    NASA Astrophysics Data System (ADS)

    Pabst, M.; Bongardt, K.; Letchford, A. P.

    1996-06-01

    The accelerator part of proposed neutron spallation sources consists of a high intensity linac and compressor ring or rapid cycling synchrotron. The most critical part of such a high current machine is to keep activation caused by particle loss along the linac or at ring injection down to an acceptable limit. Sources of particle loss along the linac can be beam mismatch, resonances of any kind, temperature transfer within a bunch and/or nonlinear internal or external forces. In addition machine errors like misalignments, tolerances, and rf errors have to be considered. All these sources cause emittance growth. The common way of setting up the beam dynamics of high intensity linacs is governed by avoiding these sources and testing it by Monte-Carlo simulations. To get information on the possible loss mechanism, the only way is to increase the particle number of the Monte-Carlo simulations and to study phase space distributions in detail. Monte-Carlo simulations with 50000 particles for the 1.334 GeV coupled cavity linac of the European Spallation Source (ESS) are presented. It is shown that it is possible to design a non-space charge dominated linac for 200 mA bunch current with almost constant emittances. A detailed study of the phase space distribution along the linac shows a small number of halo particles nearby the bunch core. This halo is acceptable for ring injection. Some information related to particle loss in the linac and in the compressor ring afterwards is extracted and comments for positioning scrapers are made.

  8. Neutron beam test of barium fluoride crystal for dark matter direct detection

    NASA Astrophysics Data System (ADS)

    Guo, C.; Ma, X. H.; Wang, Z. M.; Bao, J.; Dai, C. J.; Guan, M. Y.; Liu, J. C.; Li, Z. H.; Ren, J.; Ruan, X. C.; Yang, C. G.; Yu, Z. Y.; Zhong, W. L.

    2016-10-01

    In order to test the capabilities of Barium Fluoride (BaF2) crystal for dark matter direct detection, nuclear recoils are studied with mono-energetic neutron beam. The energy spectra of nuclear recoils, quenching factors for elastic scattering neutrons and discrimination capability between neutron inelastic scattering events and γ events are obtained for various recoil energies of the F content in BaF2.

  9. The design of an intense accelerator-based epithermal neutron beam prototype for BNCT using near-threshold reactions

    NASA Astrophysics Data System (ADS)

    Lee, Charles L.

    Near-threshold boron neutron capture therapy (BNCT) uses proton energies only tens of rev above the (pan) reaction threshold in lithium in order to reduce the moderation requirements of the neutron source. The goals of this research were to prove the feasibility of this near-threshold concept for BNCT applications, using both calculation and experiment, and design a compact neutron source prototype from these results. This required a multidisciplinary development of methods for calculation of neutron yields, head phantom dosimetry, and accelerator target heat removal. First, a method was developed to accurately calculate thick target neutron yields for both near-threshold and higher energy proton beams, in lithium metal as well as lithium compounds. After these yields were experimentally verified, they were used as neutron sources for Monte Carlo (MCNP) simulations of neutron and photon transport in head phantoms. The theoretical and experimental determination of heat removal from a target backing with multiple fins, as well as numerical calculations of heat deposition profiles based on proton energy loss in target and backing materials, demonstrated that lithium integrity can be maintained for proton beam currents up to 2.5 mA. The final design uses a proton beam energy of 1.95 MeV and has a centerline epithermal neutron flux of 2.2 × 108 n/cm2- sec/mA, an advantage depth of 5.7 cm, an advantage ratio of 4.3, and an advantage depth dose rate of 6.7 RBE- cGy/min/mA, corresponding to an irradiation time of 38 minutes with a 5 mA beam. Moderator, reflector, and shielding weigh substantially less than other accelerator BNCT designs based on higher proton energies, e.g. 2.5 MeV. The near-threshold concept is useful as a portable neutron source for hospital settings, with applications ranging from glioblastomas to melanomas and synovectomy. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

  10. Prediction of in-phantom dose distribution using in-air neutron beam characteristics for BNCS

    SciTech Connect

    Verbeke, Jerome M.

    1999-12-14

    A monoenergetic neutron beam simulation study is carried out to determine the optimal neutron energy range for treatment of rheumatoid arthritis using radiation synovectomy. The goal of the treatment is the ablation of diseased synovial membranes in joints, such as knees and fingers. This study focuses on human knee joints. Two figures-of-merit are used to measure the neutron beam quality, the ratio of the synovium absorbed dose to the skin absorbed dose, and the ratio of the synovium absorbed dose to the bone absorbed dose. It was found that (a) thermal neutron beams are optimal for treatment, (b) similar absorbed dose rates and therapeutic ratios are obtained with monodirectional and isotropic neutron beams. Computation of the dose distribution in a human knee requires the simulation of particle transport from the neutron source to the knee phantom through the moderator. A method was developed to predict the dose distribution in a knee phantom from any neutron and photon beam spectra incident on the knee. This method was revealed to be reasonably accurate and enabled one to reduce by a factor of 10 the particle transport simulation time by modeling the moderator only.

  11. Measurements of neutron dose equivalent for a proton therapy center using uniform scanning proton beams

    SciTech Connect

    Zheng Yuanshui; Liu Yaxi; Zeidan, Omar; Schreuder, Andries Niek; Keole, Sameer

    2012-06-15

    Purpose: Neutron exposure is of concern in proton therapy, and varies with beam delivery technique, nozzle design, and treatment conditions. Uniform scanning is an emerging treatment technique in proton therapy, but neutron exposure for this technique has not been fully studied. The purpose of this study is to investigate the neutron dose equivalent per therapeutic dose, H/D, under various treatment conditions for uniform scanning beams employed at our proton therapy center. Methods: Using a wide energy neutron dose equivalent detector (SWENDI-II, ThermoScientific, MA), the authors measured H/D at 50 cm lateral to the isocenter as a function of proton range, modulation width, beam scanning area, collimated field size, and snout position. They also studied the influence of other factors on neutron dose equivalent, such as aperture material, the presence of a compensator, and measurement locations. They measured H/D for various treatment sites using patient-specific treatment parameters. Finally, they compared H/D values for various beam delivery techniques at various facilities under similar conditions. Results: H/D increased rapidly with proton range and modulation width, varying from about 0.2 mSv/Gy for a 5 cm range and 2 cm modulation width beam to 2.7 mSv/Gy for a 30 cm range and 30 cm modulation width beam when 18 Multiplication-Sign 18 cm{sup 2} uniform scanning beams were used. H/D increased linearly with the beam scanning area, and decreased slowly with aperture size and snout retraction. The presence of a compensator reduced the H/D slightly compared with that without a compensator present. Aperture material and compensator material also have an influence on neutron dose equivalent, but the influence is relatively small. H/D varied from about 0.5 mSv/Gy for a brain tumor treatment to about 3.5 mSv/Gy for a pelvic case. Conclusions: This study presents H/D as a function of various treatment parameters for uniform scanning proton beams. For similar treatment

  12. Commercialization of New Beam Applications

    NASA Astrophysics Data System (ADS)

    McKeown, Joseph

    1996-05-01

    The commercialization of electron processing applications is driven by demonstrated technical advantages over current practice. Mature and reliable accelerator technology has permitted more consistent product quality and the development of new processes. However, the barriers to commercial adoption are often not amenable to solution within the laboratory alone. Aspects of the base accelerator technology, plant engineering, production, project management, financing, regulatory control, product throughput and plant operational efficiency all contribute to the business risk. Experiences in building three 10 MeV, 50 kW, IMPELA electron accelerators at approximately 8 M each and achieving cumulative operational availability greater than 98% in commercial environments have identified key parameters defining those aspects. The allowed ranges of these parameters to generate the 1.5 M annual revenue that is typically necessary to support outlays of this scale are presented. Such data have been used in proposals to displace expensive chemicals in the viscose industry, sterilize sewage sludge, detoxify chemically contaminated soils and build radiation service centers for a diversity of applications. The proposals face stiff competition from traditional chemical methods. Quantitative technical and business details of these activities are provided and an attempt is made to establish realistic expectations for the exploitation of electron beam technologies in emerging applications.

  13. Using parabolic supermirror lenses to focus and de-focus a neutron beam

    NASA Astrophysics Data System (ADS)

    Rantsiou, Emmanouela; Panzner, Tobias; Hautle, Patrick; Filges, Uwe

    2014-07-01

    We designed a focus/defocus neutron optics system, in order to investigate the performance, precision, efficiency, and operational and designing challenges of such coupled 2- lens systems, which could potentially find applications where small beam cross sections are beneficial, e.g., virtual neutron source concepts and high efficiency chopper systems. Our particular prototype (as described and discussed in this paper) has already been used in an on-going experiment, involving neutron spin filtering with dynamically polarized protons. After the designing and construction phases, we continued by performing a long series of simulations and measurements, in order to facilitate the alignment of the lenses, and investigate and understand the behaviour and output of the system. All measurements were performed at the BOA beamline at PSI. The simulations were particularly useful in aligning the lenses: tilts as small as 0.04° could easily be accounted for in our simulations and guide successfully the experimental aligning procedure of the first lens. Although harder to do in the case of two lenses, we were still able to reproduce fairly successfully with our simulations, tilts from both lenses. We have noticed (both in our experiments and simulations) that the sensitivity of such a set-up is ~ 0.01°.

  14. Electron Beam Scanning in Industrial Applications

    NASA Astrophysics Data System (ADS)

    Jongen, Yves; Herer, Arnold

    1996-05-01

    Scanned electron beams are used within many industries for applications such as sterilization of medical disposables, crosslinking of wire and cables insulating jackets, polymerization and degradation of resins and biomaterials, modification of semiconductors, coloration of gemstones and glasses, removal of oxides from coal plant flue gasses, and the curing of advanced composites and other molded forms. X-rays generated from scanned electron beams make yet other applications, such as food irradiation, viable. Typical accelerators for these applications range in beam energy from 0.5MeV to 10 MeV, with beam powers between 5 to 500kW and scanning widths between 20 and 300 cm. Since precise control of dose delivery is required in many of these applications, the integration of beam characteristics, product conveyance, and beam scanning mechanisms must be well understood and optimized. Fundamental issues and some case examples are presented.

  15. Application Guide to Neutron Multiplicity Counting

    SciTech Connect

    D. G. Langner; J. E. Stewart; M. M. Pickrell; M. S. Krick; N. Ensslin; W. C. Harker

    1998-11-01

    This document is intended to serve as a comprehensive applications guide to passive neutron multiplicity counting, a new nondestructive assay (NDA) technique developed over the past ten years. The document describes the principles of multiplicity counter design, electronics, and mathematics. Existing counters in Department of Energy (DOE) facilities are surveyed, and their operating requirements and procedures and defined. Current applications to plutonium material types found in DOE facilities are described, and estimates of the expected assay precision and bias are given. Lastly, guidelines for multiplicity counter selection and procurement are summarized. The document also includes a detailed collection of references on passive neutron coincidence and multiplicity publications over the last ten to fifteen years.

  16. Measurement of neutron yield by 62 MeV proton beam on a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Osipenko, M.; Ripani, M.; Alba, R.; Ricco, G.; Schillaci, M.; Barbagallo, M.; Boccaccio, P.; Celentano, A.; Colonna, N.; Cosentino, L.; Del Zoppo, A.; Di Pietro, A.; Esposito, J.; Figuera, P.; Finocchiaro, P.; Kostyukov, A.; Maiolino, C.; Santonocito, D.; Scuderi, V.; Viberti, C. M.

    2013-09-01

    The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a 3He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10 MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60-70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed.

  17. Ion beam and neutron output from a sub-kilojoule dense plasma focus

    NASA Astrophysics Data System (ADS)

    Ellsworth, J. L.; Falabella, S.; Schmidt, A.; Tang, V.

    2014-12-01

    We are seeking to gain a better fundamental understanding of the ion beam acceleration and neutron production dense plasma focus (DPF) device. Experiments were performed on a kilojoule level, fast rise time DPF located at LLNL. Ion beam spectra and neutron yield were measured for deuterium pinches. Visible light images of the pinch are used to determine the pinch length. In addition, an RF probe was placed just outside the cathode to measure fluctuations in Ez up to 6 GHz, which is within the range of the lower hybrid frequencies. We find these oscillations arise at a characteristic frequency near 4 GHz during the pinch. Comparisons of the neutron yield and ion beam characteristics are presented. The neutron yield is also compared to scaling laws.

  18. Ion beam and neutron output from a sub-kilojoule dense plasma focus

    SciTech Connect

    Ellsworth, J. L. Falabella, S. Schmidt, A. Tang, V.

    2014-12-15

    We are seeking to gain a better fundamental understanding of the ion beam acceleration and neutron production dense plasma focus (DPF) device. Experiments were performed on a kilojoule level, fast rise time DPF located at LLNL. Ion beam spectra and neutron yield were measured for deuterium pinches. Visible light images of the pinch are used to determine the pinch length. In addition, an RF probe was placed just outside the cathode to measure fluctuations in E{sub z} up to 6 GHz, which is within the range of the lower hybrid frequencies. We find these oscillations arise at a characteristic frequency near 4 GHz during the pinch. Comparisons of the neutron yield and ion beam characteristics are presented. The neutron yield is also compared to scaling laws.

  19. Radiation transport calculations for the ANS (Advanced Neutron Source) beam tubes

    SciTech Connect

    Engle, W.W., Jr.; Lillie, R.A.; Slater, C.O.

    1988-01-01

    The Advanced Neutron Source facility (ANS) will incorporate a large number of both radial and no-line-of-sight (NLS) beam tubes to provide very large thermal neutron fluxes to experimental facilities. The purpose of this work was to obtain comparisons for the ANS single- and split-core designs of the thermal and damage neutron and gamma-ray scalar fluxes in these beams tubes. For experimental locations far from the reactor cores, angular flux data are required; however, for close-in experimental locations, the scalar fluxes within each beam tube provide a credible estimate of the various signal to noise ratios. In this paper, the coupled two- and three-dimensional radiation transport calculations employed to estimate the scalar neutron and gamma-ray fluxes will be described and the results from these calculations will be discussed. 6 refs., 2 figs.

  20. Induction of Micronuclei in Human Fibroblasts from the Los Alamos High Energy Neutron Beam

    NASA Technical Reports Server (NTRS)

    Cox, Bradley

    2009-01-01

    The space radiation field includes a broad spectrum of high energy neutrons. Interactions between these neutrons and a spacecraft, or other material, significantly contribute to the dose equivalent for astronauts. The 15 degree beam line in the Weapons Neutron Research beam at Los Alamos Nuclear Science Center generates a neutron spectrum relatively similar to that seen in space. Human foreskin fibroblast (AG1522) samples were irradiated behind 0 to 20 cm of water equivalent shielding. The cells were exposed to either a 0.05 or 0.2 Gy entrance dose. Following irradiation, micronuclei were counted to see how the water shield affects the beam and its damage to cell nuclei. Micronuclei induction was then compared with dose equivalent data provided from a tissue equivalent proportional counter.

  1. Generation of high-energy neutron beam by fragmentation of relativistic heavy nuclei

    NASA Astrophysics Data System (ADS)

    Yurevich, Vladimir

    2016-09-01

    The phenomenon of multiple production of neutrons in reactions with heavy nuclei induced by high-energy protons and light nuclei is analyzed using a Moving Source Model. The Lorentz transformation of the obtained neutron distributions is used to study the neutron characteristics in the inverse kinematics where relativistic heavy nuclei bombard a light-mass target. The neutron beam generated at 0∘has a Gaussian shape with a maximum at the energy of the projectile nucleons and an energy resolution σE/E < 4% above 6 GeV.

  2. Facility for parity and time reversal experiments with intense epithermal (eV) neutron beams

    SciTech Connect

    Bowman, C.D.; Bowman, J.D.; Herczeg, P.; Szymanski, J.; Yuan, V.W.; Anaya, J.M.; Mortensen, R.; Postma, H.; Delheij, P.P.J.; Baker, O.K.

    1988-01-01

    A facility for polarized epithermal neutrons of high intensity is set up at the Los Alamos National Laboratory for parity-violation and time reversal experiments at neutron resonances over a wide range of neutron energies. The beam is polarized with the aid of a polarized proton target used as a neutron-spin filter. Total cross section measurements as well as capture gamma-ray experiments will be carried out. The main features of this system will be discussed. 20 refs., 5 figs.

  3. Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE

    NASA Astrophysics Data System (ADS)

    Schneider, Uwe; Hälg, Roger A.; Baiocco, Giorgio; Lomax, Tony

    2016-08-01

    The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has

  4. Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE.

    PubMed

    Schneider, Uwe; Hälg, Roger A; Baiocco, Giorgio; Lomax, Tony

    2016-08-21

    The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has

  5. Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE.

    PubMed

    Schneider, Uwe; Hälg, Roger A; Baiocco, Giorgio; Lomax, Tony

    2016-08-21

    The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has

  6. High-energy in-beam neutron measurements of metal-based shielding for accelerator-driven spallation neutron sources

    NASA Astrophysics Data System (ADS)

    DiJulio, D. D.; Cooper-Jensen, C. P.; Björgvinsdóttir, H.; Kokai, Z.; Bentley, P. M.

    2016-05-01

    Metal-based shielding plays an important role in the attenuation of harmful and unwanted radiation at an accelerator-driven spallation neutron source. At the European Spallation Source, currently under construction in Lund, Sweden, metal-based materials are planned to be used extensively as neutron guide substrates in addition to other shielding structures around neutron guides. The usage of metal-based materials in the vicinity of neutron guides however requires careful consideration in order to minimize potential background effects in a neutron instrument at the facility. Therefore, we have carried out a combined study involving high-energy neutron measurements and Monte Carlo simulations of metal-based shielding, both to validate the simulation methodology and also to investigate the benefits and drawbacks of different metal-based solutions. The measurements were carried out at The Svedberg Laboratory in Uppsala, Sweden, using a 174.1 MeV neutron beam and various thicknesses of aluminum-, iron-, and copper-based shielding blocks. The results were compared to geant4 simulations and revealed excellent agreement. Our combined study highlights the particular situations where one type of metal-based solution may be preferred over another.

  7. Characterisation of an accelerator-based neutron source for BNCT versus beam energy

    NASA Astrophysics Data System (ADS)

    Agosteo, S.; Curzio, G.; d'Errico, F.; Nath, R.; Tinti, R.

    2002-01-01

    Neutron capture in 10B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast neutron beam, generated by 7 MeV deuterons impinging on a thick target of beryllium. The neutron field was characterized at several deuteron energies (3.0-6.5 MeV) in an experimental structure installed at the Van De Graaff accelerator of the Laboratori Nazionali di Legnaro, in Italy. Thermal and epithermal neutron fluences were measured with activation techniques and fast neutron spectra were determined with superheated drop detectors (SDD). These neutron spectrometry and dosimetry studies indicated that the fast neutron dose is unacceptably high in the current design. Modifications to the current design to overcome this problem are presented.

  8. MCNP5 and GEANT4 comparisons for preliminary Fast Neutron Pencil Beam design at the University of Utah TRIGA system

    NASA Astrophysics Data System (ADS)

    Adjei, Christian Amevi

    The main objective of this thesis is twofold. The starting objective was to develop a model for meaningful benchmarking of different versions of GEANT4 against an experimental set-up and MCNP5 pertaining to photon transport and interactions. The following objective was to develop a preliminary design of a Fast Neutron Pencil Beam (FNPB) Facility to be applicable for the University of Utah research reactor (UUTR) using MCNP5 and GEANT4. The three various GEANT4 code versions, GEANT4.9.4, GEANT4.9.3, and GEANT4.9.2, were compared to MCNP5 and the experimental measurements of gamma attenuation in air. The average gamma dose rate was measured in the laboratory experiment at various distances from a shielded cesium source using a Ludlum model 19 portable NaI detector. As it was expected, the gamma dose rate decreased with distance. All three GEANT4 code versions agreed well with both the experimental data and the MCNP5 simulation. Additionally, a simple GEANT4 and MCNP5 model was developed to compare the code agreements for neutron interactions in various materials. Preliminary FNPB design was developed using MCNP5; a semi-accurate model was developed using GEANT4 (because GEANT4 does not support the reactor physics modeling, the reactor was represented as a surface neutron source, thus a semi-accurate model). Based on the MCNP5 model, the fast neutron flux in a sample holder of the FNPB is obtained to be 6.52×107 n/cm2s, which is one order of magnitude lower than gigantic fast neutron pencil beam facilities existing elsewhere. The MCNP5 model-based neutron spectrum indicates that the maximum expected fast neutron flux is at a neutron energy of ~1 MeV. In addition, the MCNP5 model provided information on gamma flux to be expected in this preliminary FNPB design; specifically, in the sample holder, the gamma flux is to be expected to be around 108 γ/cm 2s, delivering a gamma dose of 4.54×103 rem/hr. This value is one to two orders of magnitudes below the gamma

  9. Neutron Activation Analysis: Techniques and Applications

    NASA Astrophysics Data System (ADS)

    MacLellan, Ryan

    2011-04-01

    The role of neutron activation analysis in low-energy low-background experimentsis discussed in terms of comparible methods. Radiochemical neutron activation analysis is introduce. The procedure of instrumental neutron activation analysis is detailed especially with respect to the measurement of trace amounts of natural radioactivity. The determination of reactor neutron spectrum parameters required for neutron activation analysis is also presented.

  10. Neutron Activation Analysis: Techniques and Applications

    SciTech Connect

    MacLellan, Ryan

    2011-04-27

    The role of neutron activation analysis in low-energy low-background experimentsis discussed in terms of comparible methods. Radiochemical neutron activation analysis is introduce. The procedure of instrumental neutron activation analysis is detailed especially with respect to the measurement of trace amounts of natural radioactivity. The determination of reactor neutron spectrum parameters required for neutron activation analysis is also presented.

  11. SIMULATION OF NEUTRON BACKGROUNDS FROM THE ILC EXTRACTION LINE BEAM DUMP

    SciTech Connect

    Darbha, S; Keller, L.; Maruyama, T.

    2008-01-01

    The operation of the International Linear Collider (ILC) as a precision measurement machine is dependent upon the quality of the charge-coupled device (CCD) silicon vertex detector. An integrated fl ux of 1010 neutrons/cm2 incident upon the vertex detector will degrade its performance by causing displacement damage in the silicon. One source of the neutron background arises from the dumping of the spent electron and positron beams into the extraction line beam dumps. The Monte Carlo program FLUKA was used to simulate the collision of the electron beam with the dump and to determine the resulting neutron fl ux at the interaction point (IP). A collimator and tunnel were added and their effect on the fl ux was analyzed. A neutron source was then generated and directed along the extraction line towards a model of the vertex detector to determine the neutron fl ux in its silicon layers. Models of the beampipe and BeamCal, a silicon-tungsten electromagnetic calorimeter in the very forward region of the detector, were placed in the extraction line and their effects on scattering were studied. The IP fl uence was determined to be 3.7x1010 +/- 2.3x1010 neutrons/cm2/year when the tunnel and collimator were in place, with no appreciable increase in statistics when the tunnel was removed. The BeamCal was discovered to act as a collimator by signifi cantly impeding the fl ow of neutrons towards the detector. The majority of damage done to the fi rst layer of the detector was found to come from neutrons with a direct line of sight from the fi rst extraction line quadrupole QDEX1, with only a small fraction scattering off of the beampipe and into the detector. The 1 MeV equivalent neutron fl uence was determined to be 9.3x108 neutrons/cm2/year from the electron beam alone. The two beams collectively contribute double to this fl uence, which is 19% of the threshold value in one year. Future work will improve the detector model and other sources of neutron backgrounds will be

  12. SU-E-T-304: Study of Secondary Neutrons From Uniform Scanning Proton Beams

    SciTech Connect

    Islam, M; Zheng, Y; Benton, E

    2014-06-01

    Purpose: Secondary neutrons are unwanted byproducts from proton therapy and exposure from secondary radiation during treatment could increase risk of developing a secondary cancer later in a patient's lifetime. The purpose of this study is to investigate secondary neutrons from uniform scanning proton beams under various beam conditions using both measurements and Monte Carlo simulations. Methods: CR-39 Plastic Track Nuclear Detectors (PNTD) were used for the measurement. CR-39 PNTD has tissue like sensitivity to the secondary neutrons but insensitive to the therapeutic protons. In this study, we devised two experimental conditions: a) hollow-phantom; phantom is bored with a hollow cylinder along the direction of the beam so that the primary proton passes through the phantom without interacting with the phantom material, b) cylindrical-phantom; a solid cylinder of diameter close to the beam diameter is placed along the beam path. CR-39 PNTDs were placed laterally inside a 60X20X35 cm3 phantom (hollow-phantom) and in air (cylindrical-phantom) at various angles with respect to the primary beam axis. We studied for three different proton energies (78 MeV, 162 MeV and 226 MeV), using a 4 cm modulation width and 5cm diameter brass aperture for the entire experiment and simulation. A comparison of the experiment was performed using the Monte Carlo code FLUKA. Results: The measured secondary neutron dose equivalent per therapeutic primary proton dose (H/D) ranges from 2.1 ± 0.2 to 25.42 ± 2.3 mSv/Gy for the hollow phantom study, and 2.7 ± 0.3 to 46.4 ± 3.4 mSv/Gy for the cylindrical phantom study. Monte Carlo simulations predicated neutron dose equivalent from measurements within a factor of 5. Conclusion: The study suggests that the production of external neutrons is significantly higher than the production of internal neutrons.

  13. An accelerator-based epithermal neutron beam design for BNCT and dosimetric evaluation using a voxel head phantom.

    PubMed

    Lee, Deok-jae; Han, Chi Young; Park, Sung Ho; Kim, Jong Kyung

    2004-01-01

    The beam shaping assembly design has been investigated in order to improve the epithermal neutron beam for accelerator-based boron neutron capture therapy in intensity and quality, and dosimetric evaluation for the beams has been performed using both mathematical and voxel head phantoms with MCNP runs. The neutron source was assumed to be produced from a conventional 2.5 MeV proton accelerator with a thick (7)Li target. The results indicate that it is possible to enhance epithermal neutron flux remarkably as well as to embody a good spectrum shaping to epithermal neutrons only with the proper combination of moderator and reflector. It is also found that a larger number of thermal neutrons can reach deeply into the brain and, therefore, can reduce considerably the treatment time for brain tumours. Consequently, the epithermal neutron beams designed in this study can treat more effectively deep-seated brain tumours.

  14. Improvement of dose distribution by central beam shielding in boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Sakurai, Yoshinori; Ono, Koji

    2007-12-01

    Since boron neutron capture therapy (BNCT) with epithermal neutron beams started at the Kyoto University Reactor (KUR) in June 2002, nearly 200 BNCT treatments have been carried out. The epithermal neutron irradiation significantly improves the dose distribution, compared with the previous irradiation mainly using thermal neutrons. However, the treatable depth limit still remains. One effective technique to improve the limit is the central shield method. Simulations were performed for the incident neutron energies and the annular components of the neutron source. It was clear that thermal neutron flux distribution could be improved by decreasing the lower energy neutron component and the inner annular component of the incident beam. It was found that a central shield of 4-6 cm diameter and 10 mm thickness is effective for the 12 cm diameter irradiation field. In BNCT at KUR, the depth dose distribution can be much improved by the central shield method, resulting in a relative increase of the dose at 8 cm depth by about 30%. In addition to the depth dose distribution, the depth dose profile is also improved. As the dose rate in the central area is reduced by the additional shielding, the necessary irradiation time, however, increases by about 30% compared to normal treatment.

  15. Performance of beam bender for very cold neutrons

    NASA Astrophysics Data System (ADS)

    Kawabata, Yuji; Utsuro, Masahiko; Ebisawa, Tohru

    1992-11-01

    A VCN bender has been installed behind the VCN guide tube in the UCN-VCN facility of KUR. The design and the performance of the VCN bender is described in this paper. The neutron spectra at the end of the VCN bender has been measured by the reflection method using a multilayer monochromator. Neutron radiography films were used to know the neutron flux distribution. The VCN gain factor of the CNS is also derived from the spectrum measurements at the end of the VCN guide tube and the VCN bender.

  16. Neutron Energy Measurements in Radiological Emergency Response Applications

    SciTech Connect

    Sanjoy Mukhopadhyay, Paul Guss, Michael Hornish, Scott Wilde, Tom Stampahar, Michael Reed

    2009-04-30

    We present significant results in recent advances in the determination of neutron energy. Neutron energy measurements are a small but very significant part of radiological emergency response applications. Mission critical information can be obtained by analyzing the neutron energy given off from radioactive materials. In the case of searching for special nuclear materials, neutron energy information from an unknown source can be of paramount importance.

  17. Applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Gelerinter, E.; Spielberg, N.

    1980-01-01

    Wire adhesion in steel belted radial tires; carbon fibers and composite; cold welding, brazing, and fabrication; hydrogen production, separation, and storage; membrane use; catalysis; sputtering and texture; and ion beam implantation are discussed.

  18. Production cross sections of neutron rich isotopes from a 82Se beam

    NASA Astrophysics Data System (ADS)

    Tarasov, O. B.; Morrissey, D. J.; Amthor, A. M.; Bandura, L.; Baumann, T.; Bazin, D.; Berryman, J. S.; Chubarian, G.; Fukuda, N.; Gade, A.; Ginter, T. N.; Hausmann, M.; Inabe, N.; Kubo, T.; Pereira, J.; Portillo, M.; Sherrill, B. M.; Stolz, A.; Sumithrarachchi, C.; Thoennessen, M.; Weisshaar, D.

    2013-03-01

    Production cross sections for neutron-rich nuclei from the fragmentation of a 82Se beam at 139 MeV/u were measured. The longitudinal momentum distributions of 122 neutron-rich isotopes of elements 11 <= Z <= 32 were determined by varying the target thickness. Production cross sections with beryllium and tungsten targets were determined for a large number of nuclei including several isotopes first observed in this work. These are the most neutron-rich nuclides of the elements 22 <= Z <= 25 (64Ti, 67V, 69Cr, 72Mn). One event was registered consistent with 70Cr, and another one with 75Fe. A one-body Qg systematics is used to describe the production cross sections based on thermal evaporation from excited prefragments. The current results confirm those of our previous experiment with a 76Ge beam: enhanced production cross sections for neutron-rich fragments near Z = 20.

  19. Neutron spectra at two beam ports of a TRIGA Mark III reactor loaded with HEU fuel.

    PubMed

    Vega-Carrillo, H R; Hernández-Dávila, V M; Aguilar, F; Paredes, L; Rivera, T

    2014-01-01

    The neutron spectra have been measured in two beam ports, one radial and another tangential, of the TRIGA Mark III nuclear reactor from the National Institute of Nuclear Research in Mexico. Measurements were carried out with the reactor core loaded with high enriched uranium fuel. Two reactor powers, 5 and 10 W, were used during neutron spectra measurements using a Bonner sphere spectrometer with a (6)LiI(Eu) scintillator and 2, 3, 5, 8, 10 and 12 in.-diameter high-density polyethylene spheres. The neutron spectra were unfolded using the NSDUAZ unfolding code. For each spectrum total flux, mean energy and ambient dose equivalent were determined. Measured spectra show fission, epithermal and thermal neutrons, being harder in the radial beam port.

  20. Neutron spectra at two beam ports of a TRIGA Mark III reactor loaded with HEU fuel.

    PubMed

    Vega-Carrillo, H R; Hernández-Dávila, V M; Aguilar, F; Paredes, L; Rivera, T

    2014-01-01

    The neutron spectra have been measured in two beam ports, one radial and another tangential, of the TRIGA Mark III nuclear reactor from the National Institute of Nuclear Research in Mexico. Measurements were carried out with the reactor core loaded with high enriched uranium fuel. Two reactor powers, 5 and 10 W, were used during neutron spectra measurements using a Bonner sphere spectrometer with a (6)LiI(Eu) scintillator and 2, 3, 5, 8, 10 and 12 in.-diameter high-density polyethylene spheres. The neutron spectra were unfolded using the NSDUAZ unfolding code. For each spectrum total flux, mean energy and ambient dose equivalent were determined. Measured spectra show fission, epithermal and thermal neutrons, being harder in the radial beam port. PMID:23746708

  1. Ion-beam technology and applications

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.; Robson, R. R.; Sovey, J. S.

    1977-01-01

    Ion propulsion research and development yields a mature technology that is transferable to a wide range of nonpropulsive applications, including terrestrial and space manufacturing. A xenon ion source was used for an investigation into potential ion-beam applications. The results of cathode tests and discharge-chamber experiments are presented. A series of experiments encompassing a wide range of potential applications is discussed. Two types of processes, sputter deposition, and erosion were studied. Some of the potential applications are thin-film Teflon capacitor fabrication, lubrication applications, ion-beam cleaning and polishing, and surface texturing.

  2. Neutron beam monitoring for time-of-flight facilities with gaseous detectors

    NASA Astrophysics Data System (ADS)

    Aza, Eleni; Magistris, Matteo; Murtas, Fabrizio; Puddu, Silvia; Silari, Marco

    2016-01-01

    Triple Gas Electron Multipliers (GEM) for slow and fast neutrons were employed at the n_TOF facility at CERN as online beam imaging monitors and for energy spectra measurements via the time-of-flight technique. The detectors were exposed to the neutron spectrum ranging from thermal to 1 GeV, produced by spallation of 20 GeV/c protons in a lead target with a maximum intensity of 7·1012 protons per pulse. The spectrum and the 2D count distribution of the neutron beam were measured and compared at two distances from the target, 185 m and 200 m. The detectors showed radiation hardness, linear response and the ability to monitor the beam profile online with high spatial resolution.

  3. A telescope proton recoil spectrometer for fast neutron beam-lines

    NASA Astrophysics Data System (ADS)

    Cazzaniga, C.; Rebai, M.; Tardocchi, M.; Croci, G.; Nocente, M.; Ansell, S.; Frost, C. D.; Gorini, G.

    2015-07-01

    Fast neutron measurements were performed on the VESUVIO beam-line at the ISIS spallation source using a new telescope proton recoil spectrometer. Neutrons interact on a plastic target. Proton production is mainly due to elastic scattering on hydrogen nuclei and secondly due to interaction with carbon nuclei. Recoil protons are measured by a proton spectrometer, which uses in coincidence a 2.54 cm thick YAP scintillator and a 500μm thick silicon detector, measuring the full proton recoil energy and the partial deposited energy in transmission, respectively. Recoil proton spectroscopy measurements (up to Ep = 60MeV) have been interpreted by using Monte Carlo simulations of the beam-line. This instrument is of particular interest for the characterization of the ChipIr beam-line at ISIS, which was designed to feature an atmospheric-like neutron spectrum for the irradiation of micro-electronics.

  4. Exploiting neutron-rich radioactive ion beams to constrain the symmetry energy

    NASA Astrophysics Data System (ADS)

    Kohley, Z.; Christian, G.; Baumann, T.; DeYoung, P. A.; Finck, J. E.; Frank, N.; Jones, M.; Smith, J. K.; Snyder, J.; Spyrou, A.; Thoennessen, M.

    2013-10-01

    The Modular Neutron Array (MoNA) and 4 Tm Sweeper magnet were used to measure the free neutrons and heavy charged particles from the radioactive ion beam induced 32Mg+9Be reaction. The fragmentation reaction was simulated with the constrained molecular dynamics model (CoMD), which demonstrated that the of the heavy fragments and free neutron multiplicities were observables sensitive to the density dependence of the symmetry energy at subsaturation densities. Through comparison of these simulations with the experimental data, constraints on the density dependence of the symmetry energy were extracted. The advantage of radioactive ion beams as a probe of the symmetry energy is demonstrated through examination of CoMD calculations for stable and radioactive-beam-induced reactions.

  5. Neutron skyshine from end stations of the Continuous Electron Beam Accelerator Facility

    SciTech Connect

    Sun, Rai-Ko S.

    1991-12-01

    The MORSE{ }CG code from Oak Ridge National Laboratory was applied to the estimation of the neutron skyshine from three end stations of the Continuous Electron Beam Accelerator Facility (CEBAF), Newport News, VA. Calculations with other methods and an experiment had been directed at assessing the annual neutron dose equivalent at the site boundary. A comparison of results obtained with different methods is given, and the effect of different temperatures and humidities will be discussed.

  6. Neutron skyshine from end stations of the Continuous Electron Beam Accelerator Facility

    SciTech Connect

    Sun, Rai-Ko S.

    1991-12-01

    The MORSE{_}CG code from Oak Ridge National Laboratory was applied to the estimation of the neutron skyshine from three end stations of the Continuous Electron Beam Accelerator Facility (CEBAF), Newport News, VA. Calculations with other methods and an experiment had been directed at assessing the annual neutron dose equivalent at the site boundary. A comparison of results obtained with different methods is given, and the effect of different temperatures and humidities will be discussed.

  7. Aerial Neutron Detection: Neutron Signatures for Nonproliferation and Emergency Response Applications

    SciTech Connect

    Maurer, Richard J.; Stampahar, Thomas G.; Smith, Ethan X.; Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Rourke, Timothy J.; LeDonne, Jeffrey P.; Avaro, Emanuele; Butler, D. Andre; Borders, Kevin L.; Stampahar, Jezabel; Schuck, William H.; Selfridge, Thomas L.; McKissack, Thomas M.; Duncan, William W.; Hendricks, Thane J.

    2012-10-17

    From 2007 to the present, the Remote Sensing Laboratory has been conducting a series of studies designed to expand our fundamental understanding of aerial neutron detection with the goal of designing an enhanced sensitivity detection system for long range neutron detection. Over 35 hours of aerial measurements in a helicopter were conducted for a variety of neutron emitters such as neutron point sources, a commercial nuclear power reactor, nuclear reactor spent fuel in dry cask storage, depleted uranium hexafluoride and depleted uranium metal. The goals of the project were to increase the detection sensitivity of our instruments such that a 5.4 × 104 neutron/second source could be detected at 100 feet above ground level at a speed of 70 knots and to enhance the long-range detection sensitivity for larger neutron sources, i.e., detection ranges above 1000 feet. In order to increase the sensitivity of aerial neutron detection instruments, it is important to understand the dynamics of the neutron background as a function of altitude. For aerial neutron detection, studies have shown that the neutron background primarily originates from above the aircraft, being produced in the upper atmosphere by galactic cosmic-ray interactions with air molecules. These interactions produce energetic neutrons and charged particles that cascade to the earth’s surface, producing additional neutrons in secondary collisions. Hence, the neutron background increases as a function of altitude which is an impediment to long-range neutron detection. In order to increase the sensitivity for long range detection, it is necessary to maintain a low neutron background as a function of altitude. Initial investigations show the variation in the neutron background can be decreased with the application of a cosmic-ray shield. The results of the studies along with a representative data set are presented.

  8. Resumption of JRR-4 and characteristics of neutron beam for BNCT.

    PubMed

    Nakamura, T; Horiguchi, H; Kishi, T; Motohashi, J; Sasajima, F; Kumada, H

    2011-12-01

    The clinical trials of Boron Neutron Capture Therapy (BNCT) have been conducted using Japan Research Reactor No. 4 (JRR-4) at Japan Atomic Energy Agency (JAEA). On December 28th, 2007, a crack of a graphite reflector in the reactor core was found on the weld of the aluminum cladding. For this reason, specifications of graphite reflectors were renewed; dimensions of the graphite were reduced and gaps of water were increased. All existing graphite reflectors of JRR-4 were replaced by new graphite reflectors. In February 2010 the resumption of JRR-4 was carried out with new graphite reflectors. We measured the characteristics of neutron beam at the JRR-4 Neutron Beam Facility. A cylindrical water phantom of 18.6 cm diameter and 24 cm depth was set in front of the beam port with 1cm gap. TLDs and gold wires were inserted within the phantom when the phantom was irradiated. The results of the measured thermal neutron flux and the gamma dose in water were compared with that of MCNP calculation. The neutron energy spectrum of the calculation model with new reflector had little variation compared to that with old reflector, but intensities of the neutron flux and gamma dose with new reflector were rather smaller than those with old reflector. The calculated results showed the same tendency as that of the experimental results. Therefore, the clinical trials of BNCT in JRR-4 could be restarted.

  9. Initial Experimental Verification of the Neutron Beam Modeling for the LBNL BNCT Facility

    SciTech Connect

    Bleuel, D.L.; Chu, W.T.; Donahue, R.J.; Ludewigt, B.A.; McDonald, R.J.; Smith, A.R.; Stone, N.A.; Vuji, J.

    1999-01-19

    In preparation for future clinical BNCT trials, neutron production via the 7Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit,desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory's 88-inch cyclotron to characterize epithermal neutron beams created using several microampere of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF3 and Teflon, with a lead reflector to produce an epithermal spectrum strongly peaked at 10-20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorption resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity.

  10. Initial experimental verification of the neutron beam modeling for the LBNL BNCT facility

    SciTech Connect

    Bleuel, D.L.; Chu, W.T.; Donahue, R.J.; Ludewigt, B.A.; McDonald, R.J.; Smith, A.R.; Stone, N.A.; Bleuel, D.L.; Stone, N.A.; Vujic, J.

    1999-06-01

    In preparation for future clinical BNCT trials, neutron production via the {sup 7}Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit, desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory{close_quote}s 88-inch cyclotron to characterize epithermal neutron beams created using several microamperes of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF{sub 3} and Teflon, with a lead reflector to produce an epithermal spectrum strongly peaked at 10{endash}20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorbtion resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity. {copyright} {ital 1999 American Institute of Physics.}

  11. Initial experimental verification of the neutron beam modeling for the LBNL BNCT facility

    SciTech Connect

    Bleuel, D. L.; Stone, N. A.; Chu, W. T.; Donahue, R. J.; Ludewigt, B. A.; McDonald, R. J.; Smith, A. R.; Vujic, J.

    1999-06-10

    In preparation for future clinical BNCT trials, neutron production via the {sup 7}Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit, desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory's 88-inch cyclotron to characterize epithermal neutron beams created using several microamperes of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF{sub 3} and Teflon, with a lead reflector to produce an epithermal spectrum strongly peaked at 10-20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorbtion resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity.

  12. Displacement damage induce degradation of COTS array CCDs irradiated by neutron beams from a nuclear reactor

    NASA Astrophysics Data System (ADS)

    Wang, Zujun; Chen, Wei; Xiao, Zhigang; Liu, Minbo; Huang, Shaoyan; He, Baoping; Luo, Tongding

    2015-01-01

    The experiments of displacement damage effects on COTS array charge coupled devices (CCDs) induced by neutron irradiation from a nuclear reactor are presented. The charge transfer inefficiency (CTI), saturation output signal voltage (VS), dynamic range (DR), dark signal, and camera imaging quality versus neutron fluence are investigated. The degradation mechanisms of the CCDs irradiated by reactor neutron beams are also analyzed. The CTI increase due to neutron displacement damage appears to be proportional to displacement damage dose. The experiments show that VS degradation induced by neutron irradiation is much less than that induced by gamma irradiation. The dark images from the CCDs irradiated by neutrons are given to investigate dark signal degradation. The degradation forms and mechanisms of the camera imaging quality are very different between the reactor neutron displacement damage and the gamma total ionization dose damage. The three samples were exposed by 1 MeV neutron-equivalent fluences of 1×1011, 5×1011, and 1×1012 n/cm2, respectively. A sample was exposed by 1 MeV neutron-equivalent fluences up to 2×1013 n/cm2, and the CCD is a functional failure after irradiation.

  13. Monte Carlo simulation of neutron noise effects on beam position determination at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Awwal, Abdul A. S.; Leach, Richard R.; Datte, Philip; Manuel, Anastacia

    2013-09-01

    Images obtained through charged coupled device (CCD) cameras in the National Ignition Facility (NIF) are crucial to precise alignment of the 192 laser beams to the NIF target-chamber center (TCC). Cameras in and around the target chamber are increasingly exposed to the effects of neutron radiation as the laser power is increased for high energy fusion experiments. NIF was carefully designed to operate under these conditions. The present work examines the degradation of the measured TCC camera position accuracy resulting from the effects of neutron radiation on the sensor and verifies operation within design specifications. Both synthetic and real beam images are used for measuring position degradation. Monte Carlo simulations based on camera performance models are used to create images with added neutron noise. These models predict neutron induced camera noise based on exposure estimates of the cumulative single-shot fluence in the NIF environment. The neutron induced noise images are used to measure beam positions on a target calculated from the alignment images with the added noise. The effects of this noise are also determined using noise artifacts from real camera images viewing TCC to estimate beam position uncertainty.

  14. The application of specular neutron reflection to the study of surfaces and interfaces

    NASA Astrophysics Data System (ADS)

    Penfold, J.

    1992-06-01

    In recent years the specular reflection of neutrons has proved to be a valuable new technique for determining the structure of surfaces and interfaces, and a widespread application to a range of problems in surface chemistry, solid films and surface magnetism has emerged. The white beam time of flight (TOF) method for reflection measurements, exploited on a pulsed neutron source, has proved to be particularly important. Recent developments on the instrumentation and analysis methods at ISIS are presented and recent experimental results, covering a range of scientific applications are discussed.

  15. Study of muon-induced neutron production using accelerator muon beam at CERN

    SciTech Connect

    Nakajima, Y.; Lin, C. J.; Ochoa-Ricoux, J. P.; Draeger, E.; White, C. G.; Luk, K. B.; Steiner, H.

    2015-08-17

    Cosmogenic muon-induced neutrons are one of the most problematic backgrounds for various underground experiments for rare event searches. In order to accurately understand such backgrounds, experimental data with high-statistics and well-controlled systematics is essential. We performed a test experiment to measure muon-induced neutron production yield and energy spectrum using a high-energy accelerator muon beam at CERN. We successfully observed neutrons from 160 GeV/c muon interaction on lead, and measured kinetic energy distributions for various production angles. Works towards evaluation of absolute neutron production yield is underway. This work also demonstrates that the setup is feasible for a future large-scale experiment for more comprehensive study of muon-induced neutron production.

  16. PRODUCTION AND APPLICATIONS OF NEUTRONS USING PARTICLE ACCELERATORS

    SciTech Connect

    David L. Chichester

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  17. Radiation damage in silicon due to albedo neutrons emitted from hadronic beam dumps (Fe and U)

    SciTech Connect

    Gabriel, T.A.; Bishop, B.L.

    1987-01-01

    Calculations have been carried out to determine the level of radiation damage that can be expected from albedo neutrons when 1- and 5-GeV negative pions are incident on iron and uranium beam dumps. The calculated damage data are presented in several ways including neutron fluence above 0.111 MeV, 1 MeV equivalent neutron fluence, damage energy deposition, and DPA or displacements per atom. Details are presented as to the method of calculation. 14 refs., 1 fig., 1 tab.

  18. LVR-15 reactor epithermal neutron beam parameters--results of measurements.

    PubMed

    Burian, J; Klupak, V; Marek, M; Rejchrt, J; Viererbl, L; Gambarini, G; Bartesaghi, G

    2009-07-01

    The epithermal neutron beam of the LVR-15 reactor provides the appropriate conditions for varied BNCT activity. The principal parameters have been frequently determined. The following detectors have been used for the measurement: set of activation monitors of different nuclides irradiated in free beam and in the water phantom, Si semiconductor detector with (6)LiF converter, twin ionization chambers, thermoluminescence dosimeters, gel dosimeters used for imaging of separate part of dose, neutron spectrometer of Bonner type. Obtained results of measured parameters are presented in the paper.

  19. Simple microscope using a compound refractive lens and a wide-bandwidth thermal neutron beam

    SciTech Connect

    Cremer, J. T.; Park, H.; Piestrup, M. A.; Gary, C. K.; Pantell, R. H.; Flocchini, R. G.; Egbert, H. P.; Kloh, M. D.; Walker, R. B.

    2007-04-02

    The results of imaging experiments using biconcave, spherical compound refractive lenses (CRLs) and a wide-bandwidth thermal neutron beam are presented. Two CRLs were used, consisting of 155 beryllium and 120 copper lenses. The experiments were performed using a thermal neutron beam line at McClellan Nuclear Radiation Center reactor. The authors obtained micrographs of cadmium slits with up to 5x magnification and 0.3 mm resolution. The CRL resolution was superior to a pinhole camera with the same aperture diameter. The modulation transfer function (MTF) of the CRL was calculated and compared with the measured MTF at five spatial frequencies, showing good agreement.

  20. High brightness beams and applications

    SciTech Connect

    Sheffield, R.L.

    1995-09-01

    This paper describes the present research on attaining intense bright electron beams. Thermionic systems are briefly covered. Recent and past results from the photoinjector programs are given. The performance advantages and difficulties presently faced by researchers using photoinjectors is discussed. The progress that has been made in photocathode materials, both in lifetime and quantum efficiency, is covered. Finally, a discussion of emittance measurements of photoinjector systems and how the measurement is complicated by the non-thermal nature of the electron beam is presented.

  1. Neutron spectra from beam-target reactions in dense Z-pinches

    SciTech Connect

    Appelbe, B. Chittenden, J.

    2015-10-15

    The energy spectrum of neutrons emitted by a range of deuterium and deuterium-tritium Z-pinch devices is investigated computationally using a hybrid kinetic-MHD model. 3D MHD simulations are used to model the implosion, stagnation, and break-up of dense plasma focus devices at currents of 70 kA, 500 kA, and 2 MA and also a 15 MA gas puff. Instabilities in the MHD simulations generate large electric and magnetic fields, which accelerate ions during the stagnation and break-up phases. A kinetic model is used to calculate the trajectories of these ions and the neutron spectra produced due to the interaction of these ions with the background plasma. It is found that these beam-target neutron spectra are sensitive to the electric and magnetic fields at stagnation resulting in significant differences in the spectra emitted by each device. Most notably, magnetization of the accelerated ions causes the beam-target spectra to be isotropic for the gas puff simulations. It is also shown that beam-target spectra can have a peak intensity located at a lower energy than the peak intensity of a thermonuclear spectrum. A number of other differences in the shapes of beam-target and thermonuclear spectra are also observed for each device. Finally, significant differences between the shapes of beam-target DD and DT neutron spectra, due to differences in the reaction cross-sections, are illustrated.

  2. Reactor beam calculations to determine optimum delivery of epithermal neutrons for treatment of brain tumors

    SciTech Connect

    Wheeler, F.J.; Nigg, D.W.; Capala, J.

    1997-10-01

    Studies were performed to assess theoretical tumor control probability (TCP) for brain-tumor treatment with boron neutron capture therapy (BNCT) using epithermal neutron sources from reactors. The existing epithermal-neutron beams at the Brookhaven Medical Research Reactor Facility (BMRR), the Petten High Flux Reactor Facility (HWR) and the Finnish Research Reactor 1 (FIR1) have been analyzed and characterized using common analytical and measurement methods allowing for this inter-comparison. Each of these three facilities is unique and each offers an advantage in some aspect of BNCT, but none of these existing facilities excel in all neutron-beam attributes as related to BNCT. A comparison is therefore also shown for a near-optimum reactor beam which does not currently exist but which would be feasible with existing technology. This hypothetical beam is designated BNCT-1 and has a spectrum similar to the FIR-1, the mono-directionality of the HFR and the intensity of the BMRR. A beam very similar to the BNCT-1 could perhaps be achieved with modification of the BMRR, HFR, or FIR, and could certainly be realized in a new facility with today`s technology.

  3. Application of Neutron Tomography in Culture Heritage research.

    PubMed

    Mongy, T

    2014-02-01

    Neutron Tomography (NT) investigation of Culture Heritages (CH) is an efficient tool for understanding the culture of ancient civilizations. Neutron imaging (NI) is a-state-of-the-art non-destructive tool in the area of CH and plays an important role in the modern archeology. The NI technology can be widely utilized in the field of elemental analysis. At Egypt Second Research Reactor (ETRR-2), a collimated Neutron Radiography (NR) beam is employed for neutron imaging purposes. A digital CCD camera is utilized for recording the beam attenuation in the sample. This helps for the detection of hidden objects and characterization of material properties. Research activity can be extended to use computer software for quantitative neutron measurement. Development of image processing algorithms can be used to obtain high quality images. In this work, full description of ETRR-2 was introduced with up to date neutron imaging system as well. Tomographic investigation of a clay forged artifact represents CH object was studied by neutron imaging methods in order to obtain some hidden information and highlight some attractive quantitative measurements. Computer software was used for imaging processing and enhancement. Also the Astra Image 3.0 Pro software was employed for high precise measurements and imaging enhancement using advanced algorithms. This work increased the effective utilization of the ETRR-2 Neutron Radiography/Tomography (NR/T) technique in Culture Heritages activities.

  4. THE METHODS OF PRODUCING AND ANALYZING POLARIZED NEUTRON BEAMS FOR HYSPEC AT THE SNS.

    SciTech Connect

    SHAPIRO, S.M.; PASSELL, L.; ZALIZNYAK, A.; GHOSH, V.J.; LEONHARDT, W.L.; HAGEN, M.E.

    2005-04-25

    The Hybrid Spectrometer (HYSPEC), under construction at the SNS on beam line 14B, is the only inelastic scattering instrument designed to enable polarization of the incident and the scattered neutron beams. A Heusler monochromator will replace the graphite crystal for producing polarized neutrons. In the scattered beam it is planned to use a collimator--multi-channel supermirror bender array to analyze the polarization of the scattered beam over the final energy range from 5-20 meV. Other methods of polarization analysis under consideration such as transmission filters using He{sup 3}, Sm, and polarized protons are considered. Their performance is estimated and a comparison of the various methods of polarization is made.

  5. SU-F-BRE-11: Neutron Measurements Around the Varian TrueBeam Linac

    SciTech Connect

    Maglieri, R; Seuntjens, J; Kildea, J; Liang, L; DeBlois, F; Evans, M; Licea, A; Dubeau, J; Witharana, S

    2014-06-15

    Purpose: With the emergence of flattening filter free (FFF) photon beams, several authors have noted many advantages to their use. One such advantage is the decrease in neutron production by photonuclear reactions in the linac head. In the present work we investigate the reduction in neutrons from a Varian TrueBeam linac using the Nested Neutron Spectrometer (NNS, Detec). The neutron spectrum, total fluence and source strength were measured and compared for 10 MV with and without flattening filter and the effect of moderation by the room and maze was studied for the 15 MV beam. Methods: The NNS, similar to traditional Bonner sphere detectors but operated in current mode, was used to measure the neutron fluence and spectrum. The NNS was validated for use in high dose rate environments using Monte Carlo simulations and calibrated at NIST and NRC Canada. Measurements were performed at several positions within the treatment room and maze with the linac jaws closed to maximize neutron production. Results: The measurements showed a total fluence reduction between 35-40% in the room and maze when the flattening filter was removed. The neutron source strength Qn was calculated from in-room fluence measurements and was found to be 0.042 × 10{sup 2} n/Gy, 0.026 × 10{sup 2} n/Gy and 0.59 × 101{sup 2} n/Gy for the 10 MV, the 10 MV FFF and 15 MV beams, respectively. We measured ambient equivalent doses of 11 mSv/hr, 7 mSv/hr and 218 mSv/hr for the 10 MV, 10 MV FFF and 15 MV by the head. Conclusion: Our measurements revealed a decrease in total fluence, neutron source strength and equivalent dose of approximately 35-40% across the treatment room for the FFF compared to FF modes. This demonstrates, as expected, that the flattening filter is a major component of the neutron production for the TrueBeam. The authors greatly acknowledge support form the Canadian Nuclear Commission and the Natural Sciences and Engineering Research Council of Canada through the CREATE program. Co

  6. RESULTS OF BACKGROUND SUBTRACTION TECHNIQUES ON THE SPALLATION NEUTRON SOURCE BEAM LOSS MONITORS

    SciTech Connect

    Pogge, James R; Zhukov, Alexander P

    2010-01-01

    Recent improvements to the Spallation Neutron Source (SNS) beam loss monitor (BLM) designs have been made with the goal of significantly reducing background noise. This paper outlines this effort and analyzes the results. The significance of this noise reduction is the ability to use the BLM sensors [1], [2], [3] distributed throughout the SNS accelerator as a method to monitor activation of components as well as monitor beam losses.

  7. Improving the neutron-to-photon discrimination capability of detectors used for neutron dosimetry in high energy photon beam radiotherapy.

    PubMed

    Irazola, L; Terrón, J A; Bedogni, R; Pola, A; Lorenzoli, M; Sánchez-Nieto, B; Gómez, F; Sánchez-Doblado, F

    2016-09-01

    The increasing interest of the medical community to radioinduced second malignancies due to photoneutrons in patients undergoing high-energy radiotherapy, has stimulated in recent years the study of peripheral doses, including the development of some dedicated active detectors. Although these devices are designed to respond to neutrons only, their parasitic photon response is usually not identically zero and anisotropic. The impact of these facts on measurement accuracy can be important, especially in points close to the photon field-edge. A simple method to estimate the photon contribution to detector readings is to cover it with a thermal neutron absorber with reduced secondary photon emission, such as a borated rubber. This technique was applied to the TNRD (Thermal Neutron Rate Detector), recently validated for thermal neutron measurements in high-energy photon radiotherapy. The positive results, together with the accessibility of the method, encourage its application to other detectors and different clinical scenarios.

  8. Improving the neutron-to-photon discrimination capability of detectors used for neutron dosimetry in high energy photon beam radiotherapy.

    PubMed

    Irazola, L; Terrón, J A; Bedogni, R; Pola, A; Lorenzoli, M; Sánchez-Nieto, B; Gómez, F; Sánchez-Doblado, F

    2016-09-01

    The increasing interest of the medical community to radioinduced second malignancies due to photoneutrons in patients undergoing high-energy radiotherapy, has stimulated in recent years the study of peripheral doses, including the development of some dedicated active detectors. Although these devices are designed to respond to neutrons only, their parasitic photon response is usually not identically zero and anisotropic. The impact of these facts on measurement accuracy can be important, especially in points close to the photon field-edge. A simple method to estimate the photon contribution to detector readings is to cover it with a thermal neutron absorber with reduced secondary photon emission, such as a borated rubber. This technique was applied to the TNRD (Thermal Neutron Rate Detector), recently validated for thermal neutron measurements in high-energy photon radiotherapy. The positive results, together with the accessibility of the method, encourage its application to other detectors and different clinical scenarios. PMID:27337649

  9. Neutron and photon fields in the BNCT room with closed beam shutters.

    PubMed

    Marek, Milan; Viererbl, Ladislav

    2005-01-01

    The epithermal neutron beam at the LVR-15 reactor was designed for the Boron Neutron Capture Therapy (BNCT) of cancers, but it has also been used for material testing. In the case where the beam is closed with two designed shutters, there is still an indispensable background in the irradiation room, which limits the movement of persons during patient positioning before exposure or during the preparation of the samples. Because the epithermal filter of the beam was designed in a former thermal column, as a multi-layer system, it was suspected that both fast neutrons and photons penetrated the filter shielding into the room. The purpose of this study was to determine the causes of potential faulty shielding and to estimate the doses to persons who perform the irradiation experiments and/or exposure of patients. The quality of the shielding was evaluated from two-dimensional measurements of both neutron and photon distribution on the surface of the beam shutter. During the measurement both the shutters of the epithermal beam were closed and the reactor was operated at the nominal power of 9 MW. This experimental arrangement is similar to the conditions that exist when either the irradiation experiments or the exposure of patients is performed in this room. The neutron space distribution was measured using a Bonner sphere of phi 76.2 mm diameter with an LiI(TI) scintillation detector of phi 4 x 8 mm. A small Geiger-Muller tube was used for the measurement of photon distribution. The detectors were placed on a three-dimensional positioning equipment controlled by a computer, which enabled automatic measurement with 1 cm mesh step. Results of the measurement show that the background profile in the irradiation room has reasonable maximum only at the beam aperture.

  10. Neurosurgical applications of ion beams

    NASA Astrophysics Data System (ADS)

    Fabrikant, Jacob I.; Levy, Richard P.; Phillips, Mark H.; Frankel, Kenneth A.; Lyman, John T.

    1989-04-01

    The program at Donner Pavilion has applied nuclear medicine research to the diagnosis and radiosurgical treatment of life-threatening intracranial vascular disorders that affect more than half a million Americans. Stereotactic heavy-charged-particle Bragg peak radiosurgery, using narrow beams of heavy ions, demonstrates superior biological and physical characteristics in brain over X-and γ-rays, viz., improved dose distribution in the Bragg peak and sharp lateral and distal borders and less scattering of the beam. Examination of CNS tissue response and alteration of cerebral blood-flow dynamics related to heavy-ion Bragg peak radiosurgery is carried out using three-dimensional treatment planning and quantitative imaging utilizing cerebral angiography, computerized tomography (CT), magnetic resonance imaging (MRI), cine-CT, xenon X-ray CT and positron emission tomography (PET). Also under examination are the physical properties of narrow heavy-ion beams for improving methods of dose delivery and dose distribution and for establishing clinical RBE/LET and dose-response relationships for human CNS tissues. Based on the evaluation and treatment with stereotactically directed narrow beams of heavy charged particles of over 300 patients, with cerebral angiography, CT scanning and MRI and PET scanning of selected patients, plus extensive clinical and neuroradiological followup, it appears that Stereotactic charged-particle Bragg peak radiosurgery obliterates intracranial arteriovenous malformations or protects against rebleeding with reduced morbidity and no mortality. Discussion will include the method of evaluation, the clinical research protocol, the Stereotactic neuroradiological preparation, treatment planning, the radiosurgery procedure and the protocol for followup. Emphasis will be placed on the neurological results, including the neuroradiological and clinical response and early and late delayed injury in brain leading to complications (including vasogenic edema

  11. Design of a high-flux epithermal neutron beam using 235U fission plates at the Brookhaven Medical Research Reactor.

    PubMed

    Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P

    1994-10-01

    Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed.

  12. Performance characteristics of the MIT fission converter based epithermal neutron beam.

    PubMed

    Riley, K J; Binns, P J; Harling, O K

    2003-04-01

    A pre-clinical characterization of the first fission converter based epithermal neutron beam (FCB) designed for boron neutron capture therapy (BNCT) has been performed. Calculated design parameters describing the physical performance of the aluminium and Teflon filtered beam were confirmed from neutron fluence and absorbed dose rate measurements performed with activation foils and paired ionization chambers. The facility currently provides an epithermal neutron flux of 4.6 x 10(9) n cm(-2) s(-1) in-air at the patient position that makes it the most intense BNCT source in the world. This epithermal neutron flux is accompanied by very low specific photon and fast neutron absorbed doses of 3.5 +/- 0.5 and 1.4 +/- 0.2 x 10(-13) Gy cm2, respectively. A therapeutic dose rate of 1.7 RBE Gy min(-1) is achievable at the advantage depth of 97 mm when boronated phenylalanine (BPA) is used as the delivery agent, giving an average therapeutic ratio of 5.7. In clinical trials of normal tissue tolerance when using the FCB, the effective prescribed dose is due principally to neutron interactions with the nonselectively absorbed BPA present in brain. If an advanced compound is considered, the dose to brain would instead be predominately from the photon kerma induced by thermal neutron capture in hydrogen and advantage parameters of 0.88 Gy min(-1), 121 mm and 10.8 would be realized for the therapeutic dose rate, advantage depth and therapeutic ratio, respectively. This study confirms the success of a new approach to producing a high intensity, high purity epithermal neutron source that attains near optimal physical performance and which is well suited to exploit the next generation of boron delivery agents.

  13. Measurements of Neutron Capture Cross-Section for Tantalum at the Neutron Filtered Beams

    NASA Astrophysics Data System (ADS)

    Gritzay, Olena; Libman, Volodymyr

    2009-08-01

    The neutron capture cross sections of tantalum have been measured for the neutron energies 2 and 59 keV using the WWR-M Kyiv Research Reactor (KRR) of the Institute for Nuclear Research of the National Academy of Science of Ukraine. The cross sections of 181Ta (n, γ) 182Ta reaction were obtained by the activation method using a gamma-spectrometer with Ge(Li)-detector. The obtained neutron capture cross sections were compared with the known experimental data from database EXFOR/CSISRS and the ENDF libraries.

  14. High Brightness Beam Applications: Energy Recovered Linacs

    SciTech Connect

    Geoffrey A. Krafft

    2005-09-01

    In the first part of the paper some general statements are made regarding applications suitable for utilizing energy recovered linacs (ERLs) by contrasting their potential performance to that of single pass linacs and storage rings. As a result of their potential for extremely good beam quality in combination with high average beam current, ERLs have been used and considered as drivers of both free electron laser and partially coherent photon sources, from THz through X-rays; as a suitable technology for high energy electron cooling; and as a continuous or semi-continuous electron beam source for high energy colliders. At present, beam requirements tend to be highly matched to end use requirements. By reviewing some of the many examples which have either been reduced to practice, or are being explored presently, one can develop an appreciation for the wide range of parameters being considered in ERL applications.

  15. Californium-252 Neutron Sources for Medical Applications

    SciTech Connect

    Boulogne, A.R.

    2001-08-29

    Californium-252 neutron sources are being prepared to investigate the value of this radionuclide in diagnosing and treating diseases. A source resembling a cell-loaded radium needle was developed for neutron therapy. Since therapy needles are normally implanted in the body, very conservative design criteria were established to prevent leakage of radioactive. Methods are being developed to prepare very intense californium sources that could be used eventually for neutron radiography and for diagnosis by neutron activation analysis. This paper discusses these methods.

  16. Ion Beam Analysis Techniques in Interdisciplinary Applications

    SciTech Connect

    Respaldiza, Miguel A.; Ager, Francisco J.

    1999-12-31

    The ion beam analysis techniques emerge in the last years as one of the main applications of electrostatic accelerators. A short summary of the most used IBA techniques will be given as well as some examples of applications in interdisciplinary sciences.

  17. Ion beam analysis techniques in interdisciplinary applications

    SciTech Connect

    Respaldiza, Miguel A.; Ager, Francisco J.

    1999-11-16

    The ion beam analysis techniques emerge in the last years as one of the main applications of electrostatic accelerators. A short summary of the most used IBA techniques will be given as well as some examples of applications in interdisciplinary sciences.

  18. The fission track detector revisited: application to individual neutron dosimetry.

    PubMed

    Prêtre, S; Aroua, A; Boschung, M; Grecescu, M; Valley, J F; Wernli, C

    1996-08-01

    A system based on fission fragment tracks had previously been developed for individual neutron dosimetry. The dosimeter detects both fast neutrons by means of the 232Th(n,f) reaction, and thermal and albedo neutrons by means of the 235U(n,f) reaction. The fission tracks produced in a plastic foil are chemically etched and counted by spark discharges. The response of the dosimeter has recently been re-investigated in 36 different neutron fields: monoenergetic beams, reference fields near isotopic sources, and radiation fields encountered in a variety of situations inside nuclear power plants. The results obtained have been compared to those computed by convolution of the neutron spectra with the energy response functions of the dosimeters. In practical situations, it is essential to know the shape of the neutron spectrum, approximately at least, in order to perform an acceptably accurate dose evaluation. For that purpose, the neutron fields encountered inside nuclear power plants have been grouped into four categories, for which algorithms for dose evaluation have been developed. Concerning the neutron equivalent dose, the error associated with this approach does not exceed a factor of 2, a performance which is comparable to other detection systems used in the field of individual neutron dosimetry. PMID:8690594

  19. Using a Tandem Pelletron accelerator to produce a thermal neutron beam for detector testing purposes.

    PubMed

    Irazola, L; Praena, J; Fernández, B; Macías, M; Bedogni, R; Terrón, J A; Sánchez-Nieto, B; Arias de Saavedra, F; Porras, I; Sánchez-Doblado, F

    2016-01-01

    Active thermal neutron detectors are used in a wide range of measuring devices in medicine, industry and research. For many applications, the long-term stability of these devices is crucial, so that very well controlled neutron fields are needed to perform calibrations and repeatability tests. A way to achieve such reference neutron fields, relying on a 3 MV Tandem Pelletron accelerator available at the CNA (Seville, Spain), is reported here. This paper shows thermal neutron field production and reproducibility characteristics over few days.

  20. Novel methods for improvement of a Penning ion source for neutron generator applications.

    PubMed

    Sy, A; Ji, Q; Persaud, A; Waldmann, O; Schenkel, T

    2012-02-01

    Penning ion source performance for neutron generator applications is characterized by the atomic ion fraction and beam current density, providing two paths by which source performance can be improved for increased neutron yields. We have fabricated a Penning ion source to investigate novel methods for improving source performance, including optimization of wall materials and electrode geometry, advanced magnetic confinement, and integration of field emitter arrays for electron injection. Effects of several electrode geometries on discharge characteristics and extracted ion current were studied. Additional magnetic confinement resulted in a factor of two increase in beam current density. First results indicate unchanged proton fraction and increased beam current density due to electron injection from carbon nanofiber arrays.

  1. Feasibility of the Utilization of BNCT in the Fast Neutron Therapy Beam at Fermilab

    DOE R&D Accomplishments Database

    Langen, Katja; Lennox, Arlene J.; Kroc, Thomas K.; DeLuca, Jr., Paul M.

    2000-06-01

    The Neutron Therapy Facility at Fermilab has treated cancer patients since 1976. Since then more than 2,300 patients have been treated and a wealth of clinical information accumulated. The therapeutic neutron beam at Fermilab is produced by bombarding a beryllium target with 66 MeV protons. The resulting continuous neutron spectrum ranges from thermal to 66 MeV in neutron energy. It is clear that this spectrum is not well suited for the treatment of tumors with boron neutron capture therapy (BNCT) only However, since this spectrum contains thermal and epithermal components the authors are investigating whether BNCT can be used in this beam to boost the tumor dose. There are clinical scenarios in which a selective tumor dose boost of 10 - 15% could be clinically significant. For these cases the principal treatment would still be fast neutron therapy but a tumor boost could be used either to deliver a higher dose to the tumor tissue or to reduce the dose to the normal healthy tissue while maintaining the absorbed dose level in the tumor tissue.

  2. Beam asymmetry {Sigma} measurements of {pi}{sup -} photoproduction on neutrons

    SciTech Connect

    Mandaglio, G.; Manganaro, M.; Giardina, G.; Mammoliti, F.; Bellini, V.; Giusa, A.; Randieri, C.; Russo, G.; Sperduto, M. L.; Bocquet, J. P.; Lleres, A.; Rebreyend, D.; D'Angelo, A.; Fantini, A.; Franco, D.; Schaerf, C.; Vegna, V.

    2010-10-15

    The -beam asymmetry {Sigma} in the photoproduction of negative pions on quasi-free neutrons in a deuterium target was measured at the Grenoble Anneau Accelerateur Laser in the energy interval 700-1500 MeV and over a wide angular range, using polarized and tagged photons. Results are compared with recent partial-wave analyses.

  3. Demonstration of a single-crystal reflector-filter for enhancing slow neutron beams

    NASA Astrophysics Data System (ADS)

    Muhrer, G.; Schönfeldt, T.; Iverson, E. B.; Mocko, M.; Baxter, D. V.; Hügle, Th.; Gallmeier, F. X.; Klinkby, E. B.

    2016-09-01

    The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystal reflector-filter at a reflected neutron source and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains the long-wavelength benefit of the polycrystalline reflector-filter, without suffering the same loss of important intermediate wavelength neutrons. This finding extends the applicability of the reflector-filter concept to intermediate wavelengths, and furthermore indicates that the reflector-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering.

  4. Absolute calibration of neutron detectors on the C-2U advanced beam-driven FRC

    NASA Astrophysics Data System (ADS)

    Magee, R. M.; Clary, R.; Korepanov, S.; Jauregui, F.; Allfrey, I.; Garate, E.; Valentine, T.; Smirnov, A.

    2016-11-01

    In the C-2U fusion energy experiment, high power neutral beam injection creates a large fast ion population that sustains a field-reversed configuration (FRC) plasma. The diagnosis of the fast ion pressure in these high-performance plasmas is therefore critical, and the measurement of the flux of neutrons from the deuterium-deuterium (D-D) fusion reaction is well suited to the task. Here we describe the absolute, in situ calibration of scintillation neutron detectors via two independent methods: firing deuterium beams into a high density gas target and calibration with a 2 × 107 n/s AmBe source. The practical issues of each method are discussed and the resulting calibration factors are shown to be in good agreement. Finally, the calibration factor is applied to C-2U experimental data where the measured neutron rate is found to exceed the classical expectation.

  5. Neutron spectra measurement and comparison of the HFR and THOR BNCT beams.

    PubMed

    Liu, Yuan-Hao; Nievaart, Sander; Tsai, Pi-En; Liu, Hong-Ming; Moss, Ray; Jiang, Shiang-Huei

    2009-07-01

    This paper aims to measure the spectra of HB11 (high flux reactor, HFR) and the Tsing Hua open-pool reactor (THOR) boron neutron capture therapy (BNCT) beams by multiple activation foils. The self-shielding corrections were made with the aid of MCNP calculations. The initial spectra were adjusted by a sophisticated process named coarse-scaling adjustment using SAND-EX, which can adjust a given coarse-group spectrum into a fine-group structure, i.e. 640 groups, with excellent continuity. The epithermal neutron flux of the THOR beam is about three times of HB11. The thermal neutron flux, boron and gold reaction rates along the central axis of a PMMA phantom are calculated for both adjusted spectra for comparison.

  6. Silicon detectors for the neutron flux and beam profile measurements of the n_TOF facility at CERN

    NASA Astrophysics Data System (ADS)

    Musumarra, Agatino; Cosentino, Luigi; Barbagallo, Massimo; Colonna, Nicola; Damone, Lucia; Pappalardo, Alfio; Piscopo, Massimo; Finocchiaro, Paolo

    2016-09-01

    The demand of new and high precision cross section data for neutron-induced reactions is continuously growing, driven by the requirements from several fields of fundamental physics, as well as from nuclear technology, medicine, etc. Several neutron facilities are operational worldwide, and new ones are being built. In the coming years, neutron beam intensities never reached up to now will be available, thus opening new scientific and technological frontiers. Among existing facilities, n_TOF at CERN provides a high intensity pulsed neutron beam in a wide energy range (thermal to GeV) and with an extremely competitive energy resolution that also allows spectroscopy studies. In order to ensure high quality measurements, the neutron beams must be fully characterized as a function of the neutron energy, in particular by measuring the neutron flux and the beam transverse profile with high accuracy. In 2014 a new experimental area (EAR2), with a much higher neutron flux, has been completed and commissioned at n_TOF. In order to characterize the neutron beam in the newly built experimental area at n_TOF, two suitable diagnostics devices have been built by the INFN-LNS group. Both are based on silicon detectors coupled with 6Li converter foils, in particular Single Pad for the flux measurement and Position Sensitive (strips and others) for the beam profile. The devices have been completely characterized with radioactive sources and with the n_TOF neutron beam, fulfilling all the specifications and hence becoming immediately operational. The performances of these devices and their high versatility, in terms of neutron beam intensity, make them suitable to be used in both n_TOF experimental areas. A description of the devices and the main results obtained so far will be presented.

  7. Peripheral photon and neutron doses from prostate cancer external beam irradiation.

    PubMed

    Bezak, Eva; Takam, Rundgham; Marcu, Loredana G

    2015-12-01

    Peripheral photon and neutron doses from external beam radiotherapy (EBRT) are associated with increased risk of carcinogenesis in the out-of-field organs; thus, dose estimations of secondary radiation are imperative. Peripheral photon and neutron doses from EBRT of prostate carcinoma were measured in Rando phantom. (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescence dosemeters (TLDs) were inserted in slices of a Rando phantom followed by exposure to 80 Gy with 18-MV photon four-field 3D-CRT technique. The TLDs were calibrated using 6- and 18-MV X-ray beam. Neutron dose equivalents measured with CR-39 etch-track detectors were used to derive readout-to-neutron dose conversion factor for (6)LiF:Mg,Cu,P TLDs. Average neutron dose equivalents per 1 Gy of isocentre dose were 3.8±0.9 mSv Gy(-1) for thyroid and 7.0±5.4 mSv Gy(-1) for colon. For photons, the average dose equivalents per 1 Gy of isocentre dose were 0.2±0.1 mSv Gy(-1) for thyroid and 8.1±9.7 mSv Gy(-1) for colon. Paired (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P TLDs can be used to measure photon and neutron doses simultaneously. Organs in close proximity to target received larger doses from photons than those from neutrons whereas distally located organs received higher neutron versus photon dose.

  8. New neutron small-angle diffraction instrument at the Brookhaven High Flux Beam Reactor

    SciTech Connect

    Schneider, D.K.; Schoenborn, B.P.

    1982-01-01

    The new instrument utilizes cold neutrons emerging from a series of straight neutron guides. A multilayered monochromator is used in combination with a short collimator to obtain a monochromatized beam with a wavelength between 4 and 10 A and a wavelength spread of about 10%. The flux at 5 A exceeds 10/sup 6/ ns/sup -1/ cm/sup -2/ in a typical beam of 6-mm diameter at the sample. The spectrometer itself incorporates provisions for computer-controlled positioning of samples and a two-dimensional detector. At a sample-detector distance between 50 and 200 cm the detector can be centered at scattering angles of up to 45/sup 0/. The beam-defining components, the monochromator, the collimator, and various slits, are easily accessible and exchangeable for alternative devices. These features make the instrument modular and give it flexibility approaching that of standard x-ray equipment.

  9. Investigation on the reflector/moderator geometry and its effect on the neutron beam design in BNCT.

    PubMed

    Kasesaz, Y; Rahmani, F; Khalafi, H

    2015-12-01

    In order to provide an appropriate neutron beam for Boron Neutron Capture Therapy (BNCT), a special Beam Shaping Assembly (BSA) must be designed based on the neutron source specifications. A typical BSA includes moderator, reflector, collimator, thermal neutron filter, and gamma filter. In common BSA, the reflector is considered as a layer which covers the sides of the moderator materials. In this paper, new reflector/moderator geometries including multi-layer and hexagonal lattice have been suggested and the effect of them has been investigated by MCNP4C Monte Carlo code. It was found that the proposed configurations have a significant effect to improve the thermal to epithermal neutron flux ratio which is an important neutron beam parameter.

  10. Development and characterization of a D-D fast neutron generator for imaging applications.

    PubMed

    Adams, Robert; Bort, Lorenz; Zboray, Robert; Prasser, Horst-Michael

    2015-02-01

    The experimental characterization of a pulsed D-D fast neutron generator designed for fan-beam tomography applications is presented. Using Monte Carlo simulations the response of an LB6411 neutron probe was related to the neutron generator output. The yield was measured to be up to ∼10(7) neutrons/s. An aluminum block was moved stepwise between the source and a BC400 plastic scintillator detector in order to measure an edge response. This edge response was related to the neutron emitting spot size using Monte Carlo simulations and a simplified geometry-based model. The experimentally determined spot size of 2.2 mm agreed well with the simulated value of 1.5 mm. The time-dependence of pulsed output for various operating conditions was also measured. The neutron generator was found to satisfy design requirements for a planned fast neutron tomography arrangement based on a plastic scintillator detector array which is expected to be capable of producing 2D tomograms with a resolution of ∼1.5 mm. PMID:25481677

  11. Development and characterization of a D-D fast neutron generator for imaging applications.

    PubMed

    Adams, Robert; Bort, Lorenz; Zboray, Robert; Prasser, Horst-Michael

    2015-02-01

    The experimental characterization of a pulsed D-D fast neutron generator designed for fan-beam tomography applications is presented. Using Monte Carlo simulations the response of an LB6411 neutron probe was related to the neutron generator output. The yield was measured to be up to ∼10(7) neutrons/s. An aluminum block was moved stepwise between the source and a BC400 plastic scintillator detector in order to measure an edge response. This edge response was related to the neutron emitting spot size using Monte Carlo simulations and a simplified geometry-based model. The experimentally determined spot size of 2.2 mm agreed well with the simulated value of 1.5 mm. The time-dependence of pulsed output for various operating conditions was also measured. The neutron generator was found to satisfy design requirements for a planned fast neutron tomography arrangement based on a plastic scintillator detector array which is expected to be capable of producing 2D tomograms with a resolution of ∼1.5 mm.

  12. Demonstration of a Single-Crystal Reflector-Filter for Enhancing Slow Neutron Beams

    DOE PAGESBeta

    Muhrer, Guenter; Schönfeldt, Troels; Iverson, Erik B.; Mocko, Michal; Baxter, David V.; Hügle, Thomas; Gallmeier, Franz X.; Klinkby, Esben

    2016-06-14

    The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystalmore » reflector-filter and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains the long-wavelength benefit of the polycrystalline reflector-filter, without suffering the same loss of important intermediate wavelength neutrons. Ultimately, this finding extends the applicability of the reflector-filter concept to intermediate wavelengths, and furthermore indicates that the reflector-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering.« less

  13. Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

    NASA Astrophysics Data System (ADS)

    Ikeda, Yoshimasa; Taketani, Atsushi; Takamura, Masato; Sunaga, Hideyuki; Kumagai, Masayoshi; Oba, Yojiro; Otake, Yoshie; Suzuki, Hiroshi

    2016-10-01

    A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8 μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access

  14. Lifetime increased cancer risk in mice following exposure to clinical proton beam generated neutrons

    PubMed Central

    Gerweck, Leo E.; Huang, Peigen; Lu, Hsiao-Ming; Paganetti, Harald; Zhou, Yenong

    2014-01-01

    Purpose To evaluate the lifespan and risk of cancer following whole-body exposure of mice to neutrons generated by a passively scattered clinical SOBP proton beam. Methods and Materials Three hundred young adult female FVB/N mice, 152 test and 148 control, were entered into the experiment. Mice were placed in an annular cassette around a cylindrical phantom, which was positioned lateral to the mid SOBP of a 165 MeV, clinical proton beam. The average distance from the edge of the mid SOBP to the conscious active mice was 21.5 cm. The phantom was irradiated with once daily fractions of 25 Gy, 4 days per week, for 6 weeks. The age at death and cause of death, i.e., cancer and type vs. non-cancer causes, were assessed over the lifespan of the mice. Results Exposure of mice to a dose of 600 Gy of proton beam generated neutrons, reduced the median lifespan of the mice by 4.2% (Kaplan-Meier cumulative survival, P = 0.053). The relative risk of death from cancer in neutron exposed vs. control mice was 1.40 for cancer of all types (P = 0.0006) and 1.22 for solid cancers (P = 0.09). For a typical 60 Gy dose of clinical protons, the observed 22% increased risk of solid cancer would be expected to decrease by a factor of 10. Conclusions Exposure of mice to neutrons generated by a proton dose which exceeds a typical course of radiotherapy by a factor of 10, resulted in a statistically significant increase in the background incidence of leukemia and a marginally significant increase in solid cancer. The results indicate that the risk of out-of-field 2nd solid cancers from SOBP proton generated neutrons and typical treatment schedules, is 6 - 10 times less than is suggested by current neutron risk estimates. PMID:24725699

  15. Compound Refractive Lenses for Thermal Neutron Applications

    SciTech Connect

    Gary, Charles K.

    2013-11-12

    This project designed and built compound refractive lenses (CRLs) that are able to focus, collimate and image using thermal neutrons. Neutrons are difficult to manipulate compared to visible light or even x rays; however, CRLs can provide a powerful tool for focusing, collimating and imaging neutrons. Previous neutron CRLs were limited to long focal lengths, small fields of view and poor resolution due to the materials available and manufacturing techniques. By demonstrating a fabrication method that can produce accurate, small features, we have already dramatically improved the focal length of thermal neutron CRLs, and the manufacture of Fresnel lens CRLs that greatly increases the collection area, and thus efficiency, of neutron CRLs. Unlike a single lens, a compound lens is a row of N lenslets that combine to produce an N-fold increase in the refraction of neutrons. While CRLs can be made from a variety of materials, we have chosen to mold Teflon lenses. Teflon has excellent neutron refraction, yet can be molded into nearly arbitrary shapes. We designed, fabricated and tested Teflon CRLs for neutrons. We demonstrated imaging at wavelengths as short as 1.26 ? with large fields of view and achieved resolution finer than 250 μm which is better than has been previously shown. We have also determined designs for Fresnel CRLs that will greatly improve performance.

  16. Neutron focusing using capillary optics and its applications to elemental analysis

    SciTech Connect

    Chen-Mayer, H. H.; Mildner, D. F. R.; Lamaze, G. P.; Paul, R. L.; Lindstrom, R. M.

    1999-06-10

    Capillary optics (Kumakhov lenses) have been characterized and tested at two cold neutron beam facilities at the NIST reactor: the Neutron Depth Profiling (NDP) and the Prompt Gamma Activation Analysis (PGAA) spectrometers. Lenses of both multifiber and monolithic types focus cold neutron beams from guides of cm transverse dimensions onto a sub-mm spot size with higher current densities at the expense of the angular resolution, which is acceptable for applications employing neutron absorption. These lenses can improve the sensitivity and detection limits for NDP and PGAA measurements on small samples, and enable sample scanning to study spatial non-uniformity or to perform compositional mapping. A summary of the neutron focusing effort is given, with examples of a multifiber lens with on-axis focusing, a bender-focuser with off-axis focusing, and a monolithic lens with a more compact size. Preliminary results and existing problems in applying these lenses to NDP and PGAA are presented, and current and future directions are discussed.

  17. Neutron spectrum measurements in the aluminum oxide filtered beam facility at the Brookhaven Medical Research Reactor.

    PubMed

    Becker, G K; Harker, Y D; Miller, L G; Anderl, R A; Wheeler, F J

    1990-01-01

    Neutron spectrum measurements were performed on the aluminum oxide filter installed in the Brookhaven Medical Research Reactor (BMRR). For these measurements, activation foils were irradiated at the exit port of the beam facility. A technique based on dominant resonances in selected activation reactions was used to measure the epithermal neutron spectrum. The fast and intermediate-energy ranges of the neutron spectrum were measured by threshold reactions and 10B-shielded 235U fission reactions. Neutron spectral data were derived from the activation data by two approaches: (1) a short analysis which yields neutron flux values at the energies of the dominant or primary resonances in the epithermal activation reactions and integral flux data for neutrons above corresponding threshold or pseudo-threshold energies, and (2) the longer analysis which utilized all the activation data in a full-spectrum, unfolding process using the FERRET spectrum adjustment code. This paper gives a brief description of the measurement techniques, analysis methods, and the results obtained.

  18. Development and Applications of X-ray and Neutron Tomography for Nuclear and Industrial Applications

    SciTech Connect

    Sinha, Amar; Sarkar, P. S.; Kashyap, Yogesh; Roy, Tushar; Agrawal, A.

    2008-09-26

    We present an overview of work being carried out by us in the field of X-ray and neutron imaging in general and tomography in particular. We have discussed our work on microtomography, cone beam tomography, phase imaging and phase tomography, emission tomography, neutron tomography and two phase flow being carried out by us.

  19. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Babbush, C. A.; Vankampen, C. L.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic pros-thesis fixtion, and dental implants.

  20. Potential biomedical applications of ion beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Van Kampen, C. L.; Babbush, C. A.

    1976-01-01

    Electron bombardment ion thrusters used as ion sources have demonstrated a unique capability to vary the surface morphology of surgical implant materials. The microscopically rough surface texture produced by ion beam sputtering of these materials may result in improvements in the biological response and/or performance of implanted devices. Control of surface roughness may result in improved attachment of the implant to soft tissue, hard tissue, bone cement, or components deposited from blood. Potential biomedical applications of ion beam texturing discussed include: vascular prostheses, artificial heart pump diaphragms, pacemaker fixation, percutaneous connectors, orthopedic prosthesis fixation, and dental implants.

  1. Development of a fast traveling-wave beam chopper for the National Spallation Neutron Source

    SciTech Connect

    Kurennoy, S.S.; Jason, A.J.; Krawczyk, F.L.; Power, J.

    1997-10-01

    High current and severe restrictions on beam losses, below 1 nA/m, in the designed linac for the National Spallation Neutron Source (NSNS) require clean and fast--with the rise time from 2% to 98% less than 2.5 ns to accommodate a 402.5-MHz beam structure--beam chopping in its front end, at the beam energy 2.5 MeV. The R and D program includes both modification of the existing LANSCE coax-plate chopper to reduce parasitic coupling between adjacent plates, and development of new traveling-wave deflecting structures, in particular, based on a meander line. Using analytical methods and three-dimensional time-domain computer simulations the authors study transient effects in such structures to choose an optimal chopper design.

  2. LICORNE: A new and unique facility for producing intense, kinematically focused neutron beams at the IPN Orsay

    NASA Astrophysics Data System (ADS)

    Wilson, J. N.; Lebois, M.; Halipre, P.; Leniau, B.; Matea, I.; Verney, D.; Oberstedt, S.; Billnert, R.; Oberstedt, A.; Georgiev, G.; Ljungvall, J.

    2013-12-01

    LICORNE is a new neutron source recently installed at the tandem accelerator of the Institut de Physique Nucléaire d'Orsay, where a Li7-beam is used to bombard a hydrogen-containing target to produce an intense forward-directed neutron beam. The directionality of the beam, which is the unique characteristic of LICORNE, will permit the installation of γ-ray detectors dedicated to the investigation of fission fragment de-excitation which are unimpeded by neutrons from the source. A first experimental program will focus on the measurement of prompt γ-ray emission in the neutron-induced fission of fertile and fissile isotopes at incident neutron energies relevant for the core design of Generation-IV nuclear reactors. Other potential uses of the LICORNE facility for both fundamental and applied physics research are also presented.

  3. A new guide concept for a homogenous neutron beam without direct line of sight

    NASA Astrophysics Data System (ADS)

    Cussen, Leo D.; Krist, Thomas; Lieutenant, Klaus

    2015-03-01

    Neutron guide tubes are used to transport neutrons efficiently from the source to distant instruments. Ballistic neutron guides, which have an expanding section in the beginning and a contracting section in the end, reduce the total number of reflections and improve transport efficiency in long guides. Long pulse spallation sources like the European Spallation Source require very long guides. Challenges in ballistic guide design are imposed by the need for small virtual sources and the prevention of direct line of sight to the source, because both tend to produce inhomogeneous beam distributions, and the latter reduces transmission for short wavelengths. This article describes a novel ballistic guide design based on elliptic profiles. It incorporates a carefully positioned and angled kink to avoid line of sight to the source and a narrow point to position a chopper. This design reduces the number of reflections in long guides and improves transmission, especially at short wavelengths, compared to other solutions avoiding a direct line of sight.

  4. Neutron capture cross section measurements at the beam line 04 of J-PARC/MLF

    SciTech Connect

    Igashira, Masayuki; Harada, Hideo; Kiyanagi, Yoshiaki

    2012-11-12

    An Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI) at the beam line 04 of MLF (Material and Life Sciences Experimental Facilities) of J-PARC (Japan Proton Accelerator Research Complex) was installed to measure neutron capture cross sections related to the research and development of innovative nuclear systems, the study on nuclear astrophysics, etc. ANNRI has two gamma-ray spectrometers: one is a Ge detector array placed at 22 m from the coupled type moderator of the spallation neutron source of J-PARC/MLF and the other is a pair of NaI(Tl) detectors at 28 m. Until the 11th of March, 2011, when we had big earthquakes, we measured capture cross sections of Zr-93, Tc-99, Pd-107, I-129, Cm-244, Cm-246, etc. After checking and repairing ANNRI, we restarted measurements, and ANNRI has been open to worldwide users at present.

  5. A new measurement of Beam Asymmetry in Pion Photoproduction from the Neutron using CLAS

    SciTech Connect

    D. Sokhan, D. Watts, D. Branford, F. Klein

    2010-08-01

    We present a preliminary analysis of the photon beam asymmetry observable (Sigma) from the photoproduction reaction channel gamma+ n -> p + pi-. This new data was obtained using the near-4pi CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Laboratory, USA, employing a linearly polarised photon beam with an energy range 1.1 - 2.3 GeV. The measurement will provide new data to address the poorly established neutron excitation spectrum and will greatly expand the sparse world data-set both in energy and angle.

  6. Neutron Detection Alternatives to 3He for National Security Applications

    SciTech Connect

    Kouzes, Richard T.; Ely, James H.; Erikson, Luke E.; Kernan, Warnick J.; Lintereur, Azaree T.; Siciliano, Edward R.; Stephens, Daniel L.; Stromswold, David C.; Van Ginhoven, Renee M.; Woodring, Mitchell L.

    2010-11-21

    One of the main uses for 3He is in gas proportional counters for neutron detection. Large radiation detection systems deployed for homeland security and proliferation detection applications use such systems. Due to the large increase in use of 3He for homeland security and basic research, the supply has dwindled, and can no longer meet the demand. This has led to the search for an alternative technology to replace the use of 3He-based neutron detectors. In this paper, we review the testing of currently commercially available alternative technologies for neutron detection in large systems used in various national security applications.

  7. Neutron and Ion Beams Emitted from Plasma Focus (112.5 J) Device

    NASA Astrophysics Data System (ADS)

    El-Aragi M., G.

    2010-02-01

    Preliminary results of recent experiments performed within the Mather-type 112.5 J plasma focus device are presented. The ion beams from the focus device operated with deuterium filling at 1 mbar were registered using CR-39 solid state nuclear track detectors (SSNTD) and a Faraday cup detector for time-resolved measurements. The time-resolved neutron emission from the focus region measurements was detected with a photomultiplier tube (IP-28) optically coupled with a plastic scintillator NE 102.

  8. Neutron In-beam Moessbauer Spectroscopy with a Parallel Plate Avalanche Counter

    SciTech Connect

    Kubo, M.K.; Kobayashi, Y.; Yamada, Y.; Nemoto, Y.; Saito, T.; Sakai, Y.; Shoji, H.; Yonezawa, C.; Matsue, H.; Nakada, M.

    2005-04-26

    An in-beam 57Fe Moessbauer spectroscopy system using a parallel plate avalanche counter has been developed for characterizing chemical species produced after neutron capture reactions. The high signal-to-background ratio of the detector enabled us to obtain the first spectrum of semiconductor iron disulfide. A new chemical species of iron, different from the parent compound, arising from the nuclear reaction was clearly observed.

  9. Study of astrophysical ({alpha}, n) reactions using light-neutron rich radioactive nuclear beams

    SciTech Connect

    Ishiyama, Hironobu; Watanabe, Yutaka; Imai, Nobuaki; Hirayama, Yoshikazu; Miyatake, Hiroari; Tanaka, Masa-Hiko; Yoshikawa, Nobuharu; Jeong, Sunchan; Fuchi, Yoshihide; Katayama, Ichiro; Nomura, Toru; Ishikawa, Tomoko; Das, Suranjan K.; Mizoi, Yutaka; Fukuda, Tomokazu; Hashimoto, Takashi; Nishio, Katsuhisa; Mitsuoka, Shinichi; Ikezoe, Hiroshi; Matsuda, Makoto

    2006-07-12

    A systematic study of astrophysical reaction rates of ({alpha}, n) reactions on light neutron-rich nuclei using low-energy radioactive nuclear beams is in progress at the tandem facility of Japan Atomic Energy Agency. Exclusive measurements of 8Li({alpha}, n)11B and 12B({alpha}, n)15N reaction cross sections have been performed successfully. Their excitation functions together with the experimental method are presented.

  10. Prompt gamma-ray analysis using cold and thermal guided neutron beams at JAERI.

    PubMed

    Yonezawa, C

    1999-01-01

    A highly sensitive neutron-induced prompt gamma-ray analysis (PGA) system, usable at both cold and thermal neutron beam guides of JRR-3M, has been constructed. The system was designed to achieve the lowest gamma-ray background by using lithium fluoride tiles as neutron shielding, by placing the samples in a He atmosphere and by using a Ge-bismuth germanate detector system for Compton suppression. The gamma-ray spectrometer can acquire three modes of spectra simultaneously: single, Compton suppression, and pair modes. Because of the low-energy guided neutron beams and the low-background system, analytical sensitivities and detection limits better than those in usual PGA systems have been achieved. Boron and multielemental determination by a comparative standardization have been investigated, and accuracy, precision, and detection limits for the elements in various materials were evaluated. The system has been applied to the determination of B and multielements in samples of various fields such as medical, environmental, and geological sciences.

  11. Personnel neutron dose assessment upgrade: Volume 2, Field neutron spectrometer for health physics applications

    SciTech Connect

    Brackenbush, L.W.; Reece, W.D.; Miller, S.D.; Endres, G.W.R.; Durham, J.S.; Scherpelz, R.I.; Tomeraasen, P.L.; Stroud, C.M.; Faust, L.G.; Vallario, E.J.

    1988-07-01

    Both the (ICRP) and the (NCPR) have recommended an increase in neutron quality factors and the adoption of effective dose equivalent methods. The series of reports entitled Personnel Neutron Dose Assessment Upgrade (PNL-6620) addresses these changes. Volume 1 in this series of reports (Personnel Neutron Dosimetry Assessment) provided guidance on the characteristics, use, and calibration of personnel neutron dosimeters in order to meet the new recommendations. This report, Volume 2: Field Neutron Spectrometer for Health Physics Applications describes the development of a portable field spectrometer which can be set up for use in a few minutes by a single person. The field spectrometer described herein represents a significant advance in improving the accuracy of neutron dose assessment. It permits an immediate analysis of the energy spectral distribution associated with the radiation from which neutron quality factor can be determined. It is now possible to depart from the use of maximum Q by determining and realistically applying a lower Q based on spectral data. The field spectrometer is made up of two modules: a detector module with built-in electronics and an analysis module with a IBM PC/reg sign/-compatible computer to control the data acquisition and analysis of data in the field. The unit is simple enough to allow the operator to perform spectral measurements with minimal training. The instrument is intended for use in steady-state radiation fields with neutrons energies covering the fission spectrum range. The prototype field spectrometer has been field tested in plutonium processing facilities, and has been proven to operate satisfactorily. The prototype field spectrometer uses a /sup 3/He proportional counter to measure the neutron energy spectrum between 50 keV and 5 MeV and a tissue equivalent proportional counter (TEPC) to measure absorbed neutron dose.

  12. Radiobiological intercomparison of clinical neutron beams for growth inhibition in Vicia faba bean roots

    SciTech Connect

    Beauduin, M.; Gueulette, J.; Vynckier, S.; Wambersie, A.

    1989-02-01

    Relative biological effectiveness (RBE) and oxygen enhancement ratio (OER) values of different neutron beams produced at the variable energy cyclotron Cyclone of Louvain-la-Neuve (Belgium) were determined. The neutrons were obtained by bombarding a beryllium target with 34-, 45-, 65-, or 75-MeV protons or with 50-MeV deuterons. The biological system was growth inhibition in Vicia faba bean roots. Taking the p(65) + Be neutron beam as a reference, RBE values were found equal to 1.36 +/- 0.2, 1.20 +/- 0.1, 1.00 (ref), 0.98 +/- 0.1, and 1.18 +/- 0.1, respectively; the doses corresponding to 50% growth inhibition were 0.39, 0.44, 0.53, 0.54, and 0.45 Gy. For the same beams, OER values were found equal to 1.55 +/- 0.1, 1.38 +/- 0.1, 1.29 +/- 0.1, 1.41 +/- 0.1, and 1.60 +/- 0.2, respectively.

  13. Effect of Driver Impedance on Dense Plasma Focus Z-Pinch Neutron Yield and Beam Acceleration

    NASA Astrophysics Data System (ADS)

    Sears, J.; Link, A.; Ellsworth, J.; Falabella, S.; Rusnak, B.; Tang, V.; Schmidt, A.; Welch, D.

    2014-10-01

    We explore the effect of driver characteristics on dense plasma focus (DPF) neutron yield and beam acceleration using particle-in-cell (PIC) simulations of a kJ-scale DPF. Our PIC simulations are fluid for the run-down phase and transition to fully kinetic for the pinch phase. The anode-cathode boundary is driven by a circuit model of the capacitive driver, including system inductance, the load of the railgap switches, the guard resistors, and the coaxial transmission line parameters. Simulations are benchmarked to measurements of a table top kJ DPF experiment with neutron yield measured with He3-based detectors. Simulated neutron yield scales approximately with the fourth power of peak current, I4. We also probe the accelerating fields by measuring the acceleration of a 4 MeV deuteron beam and by measuring the DPF self-generated beam energy distribution, finding gradients higher than 50 MV/m. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.

  14. Pulsed neutron-beam focusing by modulating a permanent-magnet sextupole lens

    NASA Astrophysics Data System (ADS)

    Yamada, Masako; Iwashita, Yoshihisa; Ichikawa, Masahiro; Fuwa, Yasuhiro; Tongu, Hiromu; Shimizu, Hirohiko M.; Mishima, Kenji; Yamada, Norifumi L.; Hirota, Katsuya; Otake, Yoshie; Seki, Yoshichika; Yamagata, Yutaka; Hino, Masahiro; Kitaguchi, Masaaki; Garbe, Ulf; Kennedy, Shane J.; Tung Lee, Wai; Andersen, Ken H.; Guerard, Bruno; Manzin, Giuliana; Geltenbort, Peter

    2015-04-01

    We have developed a compact permanent-magnet sextupole lens for neutrons that can focus a pulsed beam with a wide wavelength range-the maximum wavelength being more than double the minimum-while sufficiently suppressing the effect of chromatic aberration. The bore diameter is #x00F8;15 mm. Three units of a double-ring sextupole with a length of 66 mm are cascaded, resulting in a total length of 198 mm. The dynamic modulation range of the unit-averaged field gradient is 1.06 × 104-5.86 × 104Tm^{-2}. Permanent magnets and newly developed torque-canceling elements make the device compact, its production costs low, and its operation simpler than that of other magnetic lenses. The efficacy of this lens was verified using very cold neutrons. The diameter of the focused beam spots over the wavelength range of 27-55 Å was the same as that of the source aperture (2 mm diameter) when the magnification of the optical arrangement was unity. The total beam flux over this wavelength range was enhanced by a factor of 43. The focusing distance from the source to the detector was 1.84 m. In addition, in a demonstration of neutron image magnification, the image of a sample mask magnified by a factor of 4.1 was observed when the magnification of the optical arrangement was 5.0.

  15. Solid state neutron dosimeter for space applications

    SciTech Connect

    Nagarkar, V.; Entine, G.; Stoppel, P.; Cirignano, L. ); Swinehart, P. )

    1992-08-01

    One of the most important contributions to the radiation exposure of astronauts engaged in space flight is the significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Under NASA sponsorship, the authors are developing a solid state neutron sensor capable of being incorporated into a very compact, flight instrument to provide high quality real time measurement of this important radiation flux. The dosimeter uses a special, high neutron sensitivity, PIN diode that is insensitive t the other forms of ionizing radiation. The dosimeter will have the ability to measure and record neutron dose over a range of 50 microgray to tens of milligrays (5 millirads to several rads) over a flight of up to 30 days. the performance characteristics of the PIN diode with a detailed description of the overall dosimeter is presented. in this paper.

  16. Solid state neutron dosimeter for space applications

    NASA Technical Reports Server (NTRS)

    Entine, Gerald; Nagargar, Vivek; Sharif, Daud

    1990-01-01

    Personnel engaged in space flight are exposed to significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Presently, there exist no compact neutron sensor capable of being integrated in a flight instrument to provide real time measurement of this radiation flux. A proposal was made to construct such an instrument using special PIN silicon diode which has the property of being insensitive to the other forms of ionizing radiation. Studies were performed to determine the design and construction of a better reading system to allow the PIN diode to be read with high precision. The physics of the device was studied, especially with respect to those factors which affect the sensitivity and reproducibility of the neutron response. This information was then used to develop methods to achieve high sensitivity at low neutron doses. The feasibility was shown of enhancing the PIN diode sensitivity to make possible the measurement of the low doses of neutrons encountered in space flights. The new PIN diode will make possible the development of a very compact, accurate, personal neutron dosimeter.

  17. PERFORMING DIAGNOSTICS ON THE SPALLATION NEUTRON SOURCE VISION BEAM LINE TO ELIMINATE HIGH VIBRATION LEVELS AND PROVIDE A SUSTAINABLE OPERATION

    SciTech Connect

    Van Hoy, Blake W

    2014-01-01

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) provides variable energy neutrons for a variety of experiments. The neutrons proceed down beam lines to the experiment hall, which houses a variety of experiments and test articles. Each beam line has one or more neutron choppers which filter the neutron beam based on the neutron energy by using a rotating neutron absorbing material passing through the neutron beam. Excessive vibration of the Vision beam line, believed to be caused by the T0 chopper, prevented the Vision beam line from operating at full capacity. This problem had been addressed several times by rebalancing/reworking the T0 beam chopper but the problem stubbornly persisted. To determine the cause of the high vibration, dynamic testing was performed. Twenty-seven accelerometer and motor current channels of data were collected during drive up, drive down, coast down, and steady-state conditions; resonance testing and motor current signature analysis were also performed. The data was analyzed for traditional mechanical/machinery issues such as misalignment and imbalance using time series analysis, frequency domain analysis, and operating deflection shape analysis. The analysis showed that the chopper base plate was experiencing an amplified response to the excitation provided by the T0 beam chopper. The amplified response was diagnosed to be caused by higher than expected base plate flexibility, possibly due to improper grouting or loose floor anchors. Based on this diagnosis, a decision was made to dismantle the beam line chopper and remount the base plate. Neutron activation of the beam line components make modifications to the beam line especially expensive and time consuming due to the radiation handling requirements, so this decision had significant financial and schedule implications. It was found that the base plate was indeed loose because of improper grouting during its initial installation. The base plate was

  18. The design, construction and performance of a variable collimator for epithermal neutron capture therapy beams.

    PubMed

    Riley, K J; Binns, P J; Ali, S J; Harling, O K

    2004-05-21

    A patient collimator for the fission converter based epithermal neutron beam (FCB) at the Massachusetts Institute of Technology Research Reactor (MITR-II) was built for clinical trials of boron neutron capture therapy (BNCT). A design was optimized by Monte Carlo simulations of the entire beam line and incorporates a modular construction for easy modifications in the future. The device was formed in-house by casting a mixture of lead spheres (7.6 mm diameter) in epoxy resin loaded with either 140 mg cm(-3) of boron carbide or 210 mg cm(-3) of lithium fluoride (95% enriched in 6Li). The cone shaped collimator allows easy field placement anywhere on the patient and is equipped with a laser indicator of central axis, beam's eye view optics and circular apertures of 80, 100, 120 and 160 mm diameter. Beam profiles and the collateral dose in a half-body phantom were measured for the 160 mm field using fission counters, activation foils as well as tissue equivalent (A-150) and graphite walled ionization chambers. Leakage radiation through the collimator contributes less than 10% to the total collateral dose up to 0.15 m beyond the edge of the aperture and becomes relatively more prominent with lateral displacement. The measured whole body dose equivalent of 24 +/- 2 mSv per Gy of therapeutic dose is comparable to doses received during conventional therapy and is due principally (60-80%) to thermal neutron capture reactions with boron. These findings, together with the dose distributions for the primary beam, demonstrate the suitability of this patient collimator for BNCT.

  19. Study of the beam-induced neutron flux and required shielding for DIANA

    NASA Astrophysics Data System (ADS)

    Best, Andreas; Couder, Manoel; Famiano, Michael; Lemut, Alberto; Wiescher, Michael

    2013-11-01

    Low energy accelerators in underground locations have emerged as a powerful tool for the measurement of critical nuclear reactions for the study of energy production and element synthesis in astrophysics. While cosmic ray induced background is substantially reduced, beam induced background on target impurities and depositions on target and collimator materials remain a matter of serious concern. The Dual Ion Accelerator for Nuclear Astrophysics (DIANA) is proposed to operate as a low-level background facility in an underground location. One of the main goals of DIANA is the study of neutron sources in stellar helium burning. For these experiments DIANA is a neutron radiation source which may affect other nearby low background level experiments. We therefore investigated the required laboratory layout to attenuate the neutron flux generated in a worst-case scenario to a level below the natural background in the underground environment. Detailed Monte Carlo calculations of the neutron propagation in the laboratory show that a neutron flux many orders of magnitude above expected values gets attenuated below the natural background rate using a 1 m thick water-shielded door as well as an emergency access/egress maze.

  20. Effects of neutron irradiation on strength of fusion reactor materials and their electron beam welded joints

    NASA Astrophysics Data System (ADS)

    Kaga, S.; Tamura, T.; Yoshida, H.; Miyata, K.

    1991-03-01

    Several aluminum alloys (A7N01, A5083 and A6061) and a ferritic martensitic steel (JFMS) were used in the present study of the effects of neutron irradiation on the strength of base materials and their electron beam welded joints. Neutron irradiation tests were performed using the core irradiation facility at Kyoto University Reactor (KUR). Neutron fluences were 2.0 × 10 22 9.1 × 10 22 and 1.7 × 10 23n/ m2 ( E > 0.1 MeV). Tensile tests were performed at 4.2, 77 and 293 K on miniature specimens prepared from both the base and welded materials. Aluminum alloys exhibit serrations in the nominal stress-nominal strain curve at 4.2 K. Little effect of neutron irradiation on the serration is observed. The ductility decrease of base metal and welded joints of aluminum alloys by neutron irradiation is smaller than that of JFMS. JFMS, especially welded joints, showed strong radiation embrittlement at cryogenic temperatures.

  1. Laser power beaming for satellite applications

    SciTech Connect

    Friedman, H.W.

    1993-09-22

    A serious consideration of laser power beaming for satellite applications appears to have grown out of a NASA mission analysis for transmitting power to lunar bases during the two week dark period. System analyses showed that laser power beaming to the moon in conjunction with efficient, large area solar cell collection panels, were an attractive alternative to other schemes such as battery storage and nuclear generators, largely because of the high space transportation costs. The primary difficulty with this scheme is the need for very high average power visible lasers. One system study indicated that lasers in excess of 10 MW at a wavelength of approximately 850 nm were required. Although such lasers systems have received much attention for military applications, their realization is still a long term goal.

  2. Laser beamed power: Satellite demonstration applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Westerlund, Larry H.

    1992-01-01

    It is possible to use a ground-based laser to beam light to the solar arrays of orbiting satellites, to a level sufficient to provide all or some of the operating power required. Near-term applications of this technology for providing supplemental power to existing satellites are discussed. Two missions with significant commercial pay-off are supplementing solar power for radiation-degraded arrays and providing satellite power during eclipse for satellites with failed batteries.

  3. SU-E-T-602: Beryllium Seeds Implant for Photo-Neutron Yield Using External Beam Therapy

    SciTech Connect

    Koren, S; Veltchev, I; Furhang, E

    2014-06-01

    Purpose: To evaluate the Neutron yield obtained during prostate external beam irradiation. Methods: Neutrons, that are commonly a radiation safety concern for photon beams with energy above 10 MV, are induced inside a PTV from Beryllium implemented seeds. A high megavoltage photon beam delivered to a prostate will yield neutrons via the reaction Be-9(γ,n)2?. Beryllium was chosen for its low gamma,n reaction cross-section threshold (1.67 MeV) to be combined with a high feasible 25 MV photon beam. This beam spectra has a most probable photon energy of 2.5 to 3.0 MeV and an average photon energy of about 5.8 MeV. For this feasibility study we simulated a Beryllium-made common seed dimension (0.1 cm diameter and 0.5 cm height) without taking into account encapsulation. We created a 0.5 cm grid loading pattern excluding the Urethra, using Variseed (Varian inc.) A total of 156 seeds were exported to a 4cm diameter prostate sphere, created in Fluka, a particle transport Monte Carlo Code. Two opposed 25 MV beams were simulated. The evaluation of the neutron dose was done by adjusting the simulated photon dose to a common prostate delivery (e.g. 7560 cGy in 42 fractions) and finding the corresponding neutron dose yield from the simulation. A variance reduction technique was conducted for the neutrons yield and transported. Results: An effective dose of 3.65 cGy due to neutrons was found in the prostate volume. The dose to central areas of the prostate was found to be about 10 cGy. Conclusion: The neutron dose yielded does not justify a clinical implant of Beryllium seeds. Nevertheless, one should investigate the Neutron dose obtained when a larger Beryllium loading is combined with commercially available 40 MeV Linacs.

  4. Dose evaluation of boron neutron capture synovectomy using the THOR epithermal neutron beam: a feasibility study

    NASA Astrophysics Data System (ADS)

    Wu, Jay; Chang, Shu-Jun; Chuang, Keh-Shih; Hsueh, Yen-Wan; Yeh, Kuan-Chuan; Wang, Jeng-Ning; Tsai, Wen-Pin

    2007-03-01

    Rheumatoid arthritis is one of the most common epidemic diseases in the world. For some patients, the treatment with steroids or nonsteroidal anti-inflammatory drugs is not effective, thus necessitating physical removal of the inflamed synovium. Alternative approaches other than surgery will provide appropriate disease control and improve the patient's quality of life. In this research, we evaluated the feasibility of conducting boron neutron capture synovectomy (BNCS) with the Tsing Hua open-pool reactor (THOR) as a neutron source. Monte Carlo simulations were performed with arthritic joint models and uncertainties were within 5%. The collimator, reflector and boron concentration were optimized to reduce the treatment time and normal tissue doses. For the knee joint, polyethylene with 40%-enriched Li2CO3 was used as the collimator material, and a rear reflector of 15 cm thick graphite and side reflector of 10 cm thick graphite were chosen. The optimized treatment time was 5.4 min for the parallel-opposed irradiation. For the finger joint, polymethyl methacrylate was used as the reflector material. The treatment time can be reduced to 3.1 min, while skin and bone doses can be effectively reduced by approximately 9% compared with treatment using the graphite reflector. We conclude that using THOR as a treatment modality for BNCS could be a feasible alternative in clinical practice.

  5. NIFTI and DISCOS: New concepts for a compact accelerator neutron source for boron neutron capture therapy applications

    SciTech Connect

    Powell, J.; Ludewig, H.; Todosow, M.; Reich, M.

    1995-06-01

    Two new concepts, NIFTI and DISCOS, are described. These concepts enable the efficient production of epithermal neutrons for BNCT (Boron Neutron Capture Therapy) medical treatment, utilizing a low current, low energy proton beam impacting on a lithium target. The NIFTI concept uses fluoride compounds, such as lead or beryllium fluoride, to efficiently degrade high energy neutrons from the lithium target to the lower energies required for BNCT. The fluoride compounds are in turn encased in an iron layer that strongly impedes the transmission of neutrons with energies above 24 KeV. Lower energy neutrons readily pass through this iron filter, which has a deep window in its scattering cross section at 24 KeV. The DISCOS concept uses a rapidly rotating, high g disc to create a series of thin ({approximately} 1 micron thickness) liquid lithium targets in the form of continuous films or sheets of discrete droplets--through which the proton beam passes. The average energy lost by a proton as it passes through a single target is small, approximately 10 KeV. Between the targets, the proton beam is re-accelerated by an applied DC electric field. The DISCOS approach enables the accelerator--target facility to operate with a beam energy only slightly above the threshold value for neutron production--resulting in an output beam of low-energy epithermal neutrons--while achieving a high yield of neutrons per milliamp of proton beam current. Parametric trade studies of the NIFTI and DISCOS concepts are described. These include analyses of a broad range of NIFTI designs using the Monte carlo MCNP neutronics code, as well as mechanical and thermal-hydraulic analyses of various DISCOS designs.

  6. Production, distribution and applications of californium-252 neutron sources.

    PubMed

    Martin, R C; Knauer, J B; Balo, P A

    2000-01-01

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 10(11) neutrons s(-1). Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordinance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations.

  7. A conceptual design of a beam-shaping assembly for boron neutron capture therapy based on deuterium-tritium neutron generators.

    PubMed

    Martín, Guido; Abrahantes, Arian

    2004-05-01

    A conceptual design of a beam-shaping assembly for boron neutron capture therapy using deuterium-tritium accelerator based neutrons source is developed. Calculations based on a simple geometry model for the radiation transport are initially performed to estimate the assembly materials and their linear dimensions. Afterward, the assembly geometry is produced, optimized and verified. In order to perform these calculations the general-purpose MCNP code is used. Irradiation time and therapeutic gain are utilized as beam assessment parameters. Metallic uranium and manganese are successfully tested for fast-to-epithermal neutron moderation. In the present beam-shaping assembly proposal, the therapeutic gain is improved by 23% and the accelerator current required for a fixed irradiation period is reduced by six times compared to previous proposals based on the same D-T reaction.

  8. Electron Beam Applications in Chemical Processing

    NASA Astrophysics Data System (ADS)

    Martin, D.; Dragusin, M.; Radoiu, M.; Moraru, R.; Oproiu, C.; Cojocaru, G.; Margarit, C.

    1997-05-01

    Our recent results in the field of polymeric materials obtained by electron beam irradiation are presented. Two types of polymeric flocculants and three hydrogels are described. The effects of radiation absorbed dose and chemical composition of the irradiated solutions upon the polymeric materials characteristics are discussed. The required absorbed dose levels to produce the polymeric flocculants are in the range of 0.4 kGy to 1 kGy, and 4 kGy to 12 kGy for hydrogels. Experimental results obtained by testing polymeric flocculants with waste water from food industry are given. Plymeric materials processing was developed on a pilot small scale level with a 0.7 kW and 5.5 MeV linac built in Romania. A new facility for application of combined electron beam and microwave irradiation in the field of polymeric materials preparation is presently under investigation. Preliminary results have demonstrated that some polymeric flocculants characteristics, such as linearity, were improved by using combined electron beam and microwave irradiation. Also, the absorbed dose levels decreases in comparison with those required when only electron beam irradiation was used.

  9. Medical applications of neutron inelastic scattering

    NASA Astrophysics Data System (ADS)

    Kehayias, Joseph J.; Banuk-Waitekus, Anathea; Valtuena, Silvia; Sheahan, Charles A.

    1999-10-01

    A sealed, D-T, pulsed neutron generator is used for the in vivo measurement of body carbon and oxygen by neutron inelastic scattering. The generator is operated at 10 KHz, at a neutron output of about 2 X 107 n/s/4(pi) . Gamma ray spectra are collected with two B4Ge3O12 crystal detectors. The measurements are used to measure fat and lean content and distribution in the body, with minimal radiation exposure (0.08 mSv). When combined with other measurements (such as total body potassium), this whole body scanning device provides us with the `quality of lean mass', a measurable outcome of treatments designed to improve nutritional status and function. The method is used in studies of human nutrition and for assessing the efficacy of new anti-obesity and anti-cachexia pharmaceuticals.

  10. Liquid Crystal-based Beam Steering Technologies for NASA Applications

    NASA Technical Reports Server (NTRS)

    Pouch, John; Nguyen, Hung; Miranda, Felix; Bos, Philip; Lavrentovich, Oleg; Wang, Xinghua; Pishnyak, Oleg; Kreminska, Liubov; Golovin, Andrii

    2006-01-01

    Liquid crystal-based beam steering devices can provide electronic beam scanning to angles above 1 milliradian, sub-microradian beam pointing accuracy, as well as wave-front correction to maintain output optical beam quality. The liquid crystal technology effort will be summarized, and the potential application of the resulting devices to NASA space-based scenarios will be described.

  11. Microwave Ion Source and Beam Injection for an Accelerator-drivenNeutron Source

    SciTech Connect

    Vainionpaa, J.H.; Gough, R.; Hoff, M.; Kwan, J.W.; Ludewigt,B.A.; Regis, M.J.; Wallig, J.G.; Wells, R.

    2007-02-15

    An over-dense microwave driven ion source capable ofproducing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomicfraction>90 percent was designed and tested with an electrostaticlow energy beam transport section (LEBT). This ion source wasincorporatedinto the design of an Accelerator Driven Neutron Source(ADNS). The other key components in the ADNS include a 6 MeV RFQaccelerator, a beam bending and scanning system, and a deuterium gastarget. In this design a 40 mA D+ beam is produced from a 6 mm diameteraperture using a 60 kV extraction voltage. The LEBT section consists of 5electrodes arranged to form 2 Einzel lenses that focus the beam into theRFQ entrance. To create the ECR condition, 2 induction coils are used tocreate ~; 875 Gauss on axis inside the source chamber. To prevent HVbreakdown in the LEBT a magnetic field clamp is necessary to minimize thefield in this region. Matching of the microwave power from the waveguideto the plasma is done by an autotuner. We observed significantimprovement of the beam quality after installing a boron nitride linerinside the ion source. The measured emittance data are compared withPBGUNS simulations.

  12. Lithium batteries: Application of neutron radiography

    NASA Astrophysics Data System (ADS)

    Kamata, Masahiro; Esaka, Takao; Fujine, Shigenori; Yoneda, Kenji; Kanda, Keiji

    Several kinds of primary and secondary commercial lithium batteries, such as CR1/3 · 1H (Fujitsu), CR1220 and BR435 (Panasonic), ML1220 (Sanyo Excel) were investigated using neutron radiography; the variation of the lithium distribution inside these batteries upon discharging (and charging) were clarified by analyzing their visualized images. It was demonstrated that neutron radiography is a potential and useful method, especially in evaluating the reversibility of rechargeable batteries, which have been used under different discharging/charging conditions.

  13. Monte Carlo Simulations on Neutron Transport and Absorbed Dose in Tissue-Equivalent Phantoms Exposed to High-Flux Epithermal Neutron Beams

    NASA Astrophysics Data System (ADS)

    Bartesaghi, G.; Gambarini, G.; Negri, A.; Carrara, M.; Burian, J.; Viererbl, L.

    2010-04-01

    Presently there are no standard protocols for dosimetry in neutron beams for boron neutron capture therapy (BNCT) treatments. Because of the high radiation intensity and of the presence at the same time of radiation components having different linear energy transfer and therefore different biological weighting factors, treatment planning in epithermal neutron fields for BNCT is usually performed by means of Monte Carlo calculations; experimental measurements are required in order to characterize the neutron source and to validate the treatment planning. In this work Monte Carlo simulations in two kinds of tissue-equivalent phantoms are described. The neutron transport has been studied, together with the distribution of the boron dose; simulation results are compared with data taken with Fricke gel dosimeters in form of layers, showing a good agreement.

  14. It may be Possible to Use a Neutron Beam as Propulsion for Spacecraft

    NASA Astrophysics Data System (ADS)

    Kriske, Richard M.

    2016-01-01

    It may be possible to keep Xenon 135 in a Superpositioned state with Xe-136 and Cs 135, the two decay products of Xenon 135. This may be done using a Gamma Ray or an X-ray Laser. At first glance it has the look and feel of yet another Noble Gas Laser. The difference is that it uses Neutron states within the Nucleus. The Neutrons would be emitted with a modulated Gamma or X-ray photon. In essence it may be possible to have a totally new type of Laser---This author calls them "Matter Lasers", where a lower energy photon with fewer Quantum Numbers would be used with a Noble Gas to produce a particle beam with higher energy and more Quantum Numbers. It may be possible to replace cumbersome particle accelerators with this type of Laser, to make mass from energy, via a Neutron Gas. This would be a great technological advance in Rocket Propulsion as well; low mass photon to high mass particle, such as a Higgs particle or a Top Quark. The Xenon 135, could come from a Fission Reactor within the Space Craft, as it is a reactor poison. The workings of an X-ray laser is already known and table top versions of it have been developed. Gamma Ray lasers are already in use and have been tested. A Laser would have a columnated beam with a very precise direction, unlike just a Neutron source which would go in all directions. Of course this beam could be used as a spectroscopic tool as well, in order to determine the composition of the matter that the spacecraft encounters. The spectroscopic tool could look for "Dark Matter" and other exotic types of matter that may occur in outerspace. The spacecraft could potentially reach "near speed of light velocities" in a fairly short time, since the Laser would be firing off massive particles, with great momentum. Lastly the precise Neutron beam could be used as a very powerful weapon or as a way of clearing space debri, since it could "force Nuclear Reactions" onto the object being fired upon, making it the ultimate space weapon, and

  15. Microdosimetric study for secondary neutrons in phantom produced by a 290 MeV/nucleon carbon beam.

    PubMed

    Endo, Satoru; Tanaka, Kenichi; Takada, Masashi; Onizuka, Yoshihiko; Miyahara, Nobuyuki; Sato, Tatsuhiko; Ishikawa, Masayori; Maeda, Naoko; Hayabuchi, Naofumi; Shizuma, Kiyoshi; Hoshi, Masaharu

    2007-09-01

    Absorbed doses from main charged-particle beams and charged-particle fragments have been measured with high accuracy for particle therapy, but there are few reports for doses from neutron components produced as fragments. This study describes the measurements on neutron doses produced by carbon beams; microdosimetric distributions of secondary neutrons produced by 290 MeV/nucleon carbon beams have been measured by using a tissue equivalent proportional counter at the Heavy Ion Medical Accelerator in Chiba, Japan at the National Institute of Radiological Sciences. The microdosimetric distributions of the secondary neutron were measured on the distal and lateral faces of a body-simulated acrylic phantom (300 mm height x 300 mm width x 253 mm thickness). To confirm the dose measurements, the neutron energy spectra produced by incident carbon beams in the acrylic phantom were simulated by the particle and heavy ion transport code system. The absorbed doses obtained by multiplying the simulated neutron energy spectra with the kerma factor calculated by MCNPX agree with the corresponding experimental data fairly well. Downstream of the Bragg peak, the ratio of the neutron dose to the carbon dose at the Bragg peak was found to be a maximum of 1.4 x 10(-4) and the ratio of neutron dose was a maximum of 3.0 x 10(-7) at a lateral face of the acrylic phantom. The ratios of neutrons to charged particle fragments were 11% to 89% in the absorbed doses at the lateral and the distal faces of the acrylic phantom. We can conclude that the treatment dose will not induce serious secondary neutron effects at distances greater than 90 mm from the Bragg peak in carbon particle therapy.

  16. Microdosimetric study for secondary neutrons in phantom produced by a 290 MeV/nucleon carbon beam

    SciTech Connect

    Endo, Satoru; Tanaka, Kenichi; Takada, Masashi; Onizuka, Yoshihiko; Miyahara, Nobuyuki; Sato, Tatsuhiko; Ishikawa, Masayori; Maeda, Naoko; Hayabuchi, Naofumi; Shizuma, Kiyoshi; Hoshi, Masaharu

    2007-09-15

    Absorbed doses from main charged-particle beams and charged-particle fragments have been measured with high accuracy for particle therapy, but there are few reports for doses from neutron components produced as fragments. This study describes the measurements on neutron doses produced by carbon beams; microdosimetric distributions of secondary neutrons produced by 290 MeV/nucleon carbon beams have been measured by using a tissue equivalent proportional counter at the Heavy Ion Medical Accelerator in Chiba, Japan at the National Institute of Radiological Sciences. The microdosimetric distributions of the secondary neutron were measured on the distal and lateral faces of a body-simulated acrylic phantom (300 mm heightx300 mm widthx253 mm thickness). To confirm the dose measurements, the neutron energy spectra produced by incident carbon beams in the acrylic phantom were simulated by the particle and heavy ion transport code system. The absorbed doses obtained by multiplying the simulated neutron energy spectra with the kerma factor calculated by MCNPX agree with the corresponding experimental data fairly well. Downstream of the Bragg peak, the ratio of the neutron dose to the carbon dose at the Bragg peak was found to be a maximum of 1.4x10{sup -4} and the ratio of neutron dose was a maximum of 3.0x10{sup -7} at a lateral face of the acrylic phantom. The ratios of neutrons to charged particle fragments were 11% to 89% in the absorbed doses at the lateral and the distal faces of the acrylic phantom. We can conclude that the treatment dose will not induce serious secondary neutron effects at distances greater than 90 mm from the Bragg peak in carbon particle therapy.

  17. Spatial variation of radiation quality during moving beam therapy with 14 MeV [d(0.25)+T] neutrons.

    PubMed

    Herskind, C; Loncol, Th; Höver, K H

    2002-01-01

    In conformal moving beam therapy with fast neutrons, the contributions to dose from the direct beam, scattered radiation and the gamma component vary with the position in the phantom. To determine this variation in radiation quality, microdosimetric measurements of energy deposition spectra were performed at different position in a therapy phantom. Fixed beam irradiation at different incidence angles showed strong changes in the lineal energy spectrum. An increase of slow protons (20 < y < 110 keV.micron-1) and a decrease of fast protons (2 < y < 20 keV.micron-1) was seen for irradiation outside the direct beam. During moving beam irradiation, different positions on the same isodose curves (55% or 35%) showed differences in YD of up to 5%. Variations in the quality parameter, R, determined by applying an empirical biological weighting function, were of similar magnitude. Thus, spatial variations in radiation quality should be taken into account in biological dose planning for moving beam neutron therapy.

  18. Photo neutron dose equivalent rate in 15 MV X-ray beam from a Siemens Primus Linac

    PubMed Central

    Ghasemi, A.; Pourfallah, T. Allahverdi; Akbari, M. R.; Babapour, H.; Shahidi, M.

    2015-01-01

    Fast and thermal neutron fluence rates from a 15 MV X-ray beams of a Siemens Primus Linac were measured using bare and moderated BF3 proportional counter inside the treatment room at different locations. Fluence rate values were converted to dose equivalent rate (DER) utilizing conversion factors of American Association of Physicist in Medicine's (AAPM) report number 19. For thermal neutrons, maximum and minimum DERs were 3.46 × 10-6 (3 m from isocenter in +Y direction, 0 × 0 field size) and 8.36 × 10-8 Sv/min (in maze, 40 × 40 field size), respectively. For fast neutrons, maximum DERs using 9” and 3” moderators were 1.6 × 10-5 and 1.74 × 10-5 Sv/min (2 m from isocenter in +Y direction, 0 × 0 field size), respectively. By changing the field size, the variation in thermal neutron DER was more than the fast neutron DER and the changes in fast neutron DER were not significant in the bunker except inside the radiation field. This study showed that at all points and distances, by decreasing field size of the beam, thermal and fast neutron DER increases and the number of thermal neutrons is more than fast neutrons. PMID:26170555

  19. Radiation injury of boron neutron capture therapy using mixed epithermal- and thermal neutron beams in patients with malignant glioma.

    PubMed

    Kageji, T; Nagahiro, S; Mizobuchi, Y; Toi, H; Nakagawa, Y; Kumada, H

    2004-11-01

    The purpose of this study was to clarify the radiation injury in acute or delayed stage after boron neutron capture therapy (BNCT) using mixed epithermal- and thermal neutron beams in patients with malignant glioma. Eighteen patients with malignant glioma underwent mixed epithermal- and thermal neutron beam and sodium borocaptate between 1998 and 2004. The radiation dose (i.e. physical dose of boron n-alpha reaction) in the protocol used between 1998 and 2000 (Protocol A, n = 8) prescribed a maximum tumor volume dose of 15 Gy. In 2001, a new dose-escalated protocol was introduced (Protocol B, n = 4); it prescribes a minimum tumor volume dose of 18 Gy or, alternatively, a minimum target volume dose of 15 Gy. Since 2002, the radiation dose was reduced to 80-90% dose of Protocol B because of acute radiation injury. A new Protocol was applied to 6 glioblastoma patients (Protocol C, n = 6). The average values of the maximum vascular dose of brain surface in Protocol A, B and C were 11.4+/-4.2 Gy, 15.7+/-1.2 and 13.9+/-3.6 Gy, respectively. Acute radiation injury such as a generalized convulsion within 1 week after BNCT was recognized in three patients of Protocol B. Delayed radiation injury such as a neurological deterioration appeared 3-6 months after BNCT, and it was recognized in 1 patient in Protocol A, 5 patients in Protocol B. According to acute radiation injury, the maximum vascular dose was 15.8+/-1.3 Gy in positive and was 12.6+/-4.3 Gy in negative. There was no significant difference between them. According to the delayed radiation injury, the maximum vascular dose was 13.8+/-3.8 Gy in positive and was 13.6+/-4.9 Gy in negative. There was no significant difference between them. The dose escalation is limited because most patients in Protocol B suffered from acute radiation injury. We conclude that the maximum vascular dose does not exceed over 12 Gy to avoid the delayed radiation injury, especially, it should be limited under 10 Gy in the case that tumor

  20. Experimental and Simulated Characterization of a Beam Shaping Assembly for Accelerator- Based Boron Neutron Capture Therapy (AB-BNCT)

    SciTech Connect

    Burlon, Alejandro A.; Valda, Alejandro A.; Girola, Santiago; Minsky, Daniel M.; Kreiner, Andres J.

    2010-08-04

    In the frame of the construction of a Tandem Electrostatic Quadrupole Accelerator facility devoted to the Accelerator-Based Boron Neutron Capture Therapy, a Beam Shaping Assembly has been characterized by means of Monte-Carlo simulations and measurements. The neutrons were generated via the {sup 7}Li(p, n){sup 7}Be reaction by irradiating a thick LiF target with a 2.3 MeV proton beam delivered by the TANDAR accelerator at CNEA. The emerging neutron flux was measured by means of activation foils while the beam quality and directionality was evaluated by means of Monte Carlo simulations. The parameters show compliance with those suggested by IAEA. Finally, an improvement adding a beam collimator has been evaluated.

  1. Photopolymerizable nanocomposite photonic materials and their holographic applications in light and neutron optics

    PubMed Central

    Tomita, Yasuo; Hata, Eiji; Momose, Keisuke; Takayama, Shingo; Liu, Xiangming; Chikama, Katsumi; Klepp, Jürgen; Pruner, Christian; Fally, Martin

    2016-01-01

    We present an overview of recent investigations of photopolymerizable nanocomposite photonic materials in which, thanks to their high degree of material selectivity, recorded volume gratings possess high refractive index modulation amplitude and high mechanical/thermal stability at the same time, providing versatile applications in light and neutron optics. We discuss the mechanism of grating formation in holographically exposed nanocomposite materials, based on a model of the photopolymerization-driven mutual diffusion of monomer and nanoparticles. Experimental inspection of the recorded grating’s morphology by various physicochemical and optical methods is described. We then outline the holographic recording properties of volume gratings recorded in photopolymerizable nanocomposite materials consisting of inorganic/organic nanoparticles and monomers having various photopolymerization mechanisms. Finally, we show two examples of our holographic applications, holographic digital data storage and slow-neutron beam control.

  2. Photopolymerizable nanocomposite photonic materials and their holographic applications in light and neutron optics

    PubMed Central

    Tomita, Yasuo; Hata, Eiji; Momose, Keisuke; Takayama, Shingo; Liu, Xiangming; Chikama, Katsumi; Klepp, Jürgen; Pruner, Christian; Fally, Martin

    2016-01-01

    We present an overview of recent investigations of photopolymerizable nanocomposite photonic materials in which, thanks to their high degree of material selectivity, recorded volume gratings possess high refractive index modulation amplitude and high mechanical/thermal stability at the same time, providing versatile applications in light and neutron optics. We discuss the mechanism of grating formation in holographically exposed nanocomposite materials, based on a model of the photopolymerization-driven mutual diffusion of monomer and nanoparticles. Experimental inspection of the recorded grating’s morphology by various physicochemical and optical methods is described. We then outline the holographic recording properties of volume gratings recorded in photopolymerizable nanocomposite materials consisting of inorganic/organic nanoparticles and monomers having various photopolymerization mechanisms. Finally, we show two examples of our holographic applications, holographic digital data storage and slow-neutron beam control. PMID:27594769

  3. Production, Distribution, and Applications of Californium-252 Neutron Sources

    SciTech Connect

    Balo, P.A.; Knauer, J.B.; Martin, R.C.

    1999-10-03

    reencapsulators domestically and internationally. Sealed {sup 252}Cf sources are also available for loan to agencies and subcontractors of the U.S. government and to universities for educational, research, and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of {sup 252}Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments, and irradiation of rice to induce genetic mutations.

  4. One-dimensional neutron focusing with large beam divergence by 400mm-long elliptical supermirror

    NASA Astrophysics Data System (ADS)

    Nagano, M.; Yamaga, F.; Yamazaki, D.; Maruyama, R.; Hayashida, H.; Soyama, K.; Yamamura, K.

    2012-02-01

    Reflective optics is one of the most useful techniques for focusing a neutron beam with a wide wavelength range since there is no chromatic aberration. Neutrons can be focused within a small area of less than 1 mm2 by high-performance aspherical supermirrors with high figure accuracy and a low smooth substrate surface and a multilayer interface. Increasing the mirror size is essential for increasing the focusing gain. We have developed a fabrication process that combines conventional precision grinding, HF dip etching, numerically controlled local wet etching (NC-LWE) figuring, low-pressure polishing and ion beam sputtering deposition of the supermirror coating to fabricate a large aspherical supermirror. We designed and fabricated an piano-elliptical mirror with large clear aperture size using the developed fabrication process. We obtained a figure error of 0.43 μm p-v and an rms roughness of less than 0.2 nm within an effective reflective length of 370 mm. A NiC/Ti supermirror with m = 4 was deposited on the substrate using ion beam sputtering equipment. The results of focusing experiments show that a focusing gain of 52 at the peak intensity was achieved compared with the case without focusing. Furthermore, the result of imaging plate measurements indicated that the FWHM focusing width of the fabricated mirror is 0.128 mm.

  5. Design and construction of a thermal neutron beam for BNCT at Tehran Research Reactor.

    PubMed

    Kasesaz, Yaser; Khalafi, Hossein; Rahmani, Faezeh; Ezzati, Arsalan; Keyvani, Mehdi; Hossnirokh, Ashkan; Shamami, Mehrdad Azizi; Amini, Sepideh

    2014-12-01

    An irradiation facility has been designed and constructed at Tehran Research Reactor (TRR) for the treatment of shallow tumors using Boron Neutron Capture Therapy (BNCT). TRR has a thermal column which is about 3m in length with a wide square cross section of 1.2×1.2m(2). This facility is filled with removable graphite blocks. The aim of this work is to perform the necessary modifications in the thermal column structure to meet thermal BNCT beam criteria recommended by International Atomic Energy Agency. The main modifications consist of rearranging graphite blocks and reducing the gamma dose rate at the beam exit. Activation foils and TLD700 dosimeter have been used to measure in-air characteristics of the neutron beam. According to the measurements, a thermal flux is 5.6×10(8) (ncm(-2)s(-1)), a cadmium ratio is 186 for gold foils and a gamma dose rate is 0.57Gy h(-1).

  6. Cluster-transfer reactions with radioactive beams: A spectroscopic tool for neutron-rich nuclei

    NASA Astrophysics Data System (ADS)

    Bottoni, S.; Leoni, S.; Fornal, B.; Raabe, R.; Rusek, K.; Benzoni, G.; Bracco, A.; Crespi, F. C. L.; Morales, A. I.; Bednarczyk, P.; Cieplicka-Oryńczak, N.; Królas, W.; Maj, A.; Szpak, B.; Callens, M.; Bouma, J.; Elseviers, J.; De Witte, H.; Flavigny, F.; Orlandi, R.; Reiter, P.; Seidlitz, M.; Warr, N.; Siebeck, B.; Hellgartner, S.; Mücher, D.; Pakarinen, J.; Vermeulen, M.; Bauer, C.; Georgiev, G.; Janssens, R. V. F.; Balabanski, D.; Sferrazza, M.; Kowalska, M.; Rapisarda, E.; Voulot, D.; Lozano Benito, M.; Wenander, F.

    2015-08-01

    An exploratory experiment performed at REX-ISOLDE to investigate cluster-transfer reactions with radioactive beams in inverse kinematics is presented. The aim of the experiment was to test the potential of cluster-transfer reactions at the Coulomb barrier as a mechanism to explore the structure of exotic neutron-rich nuclei. The reactions 7Li(98Rb,α xn ) and 7Li(98Rb,t xn ) were studied through particle-γ coincidence measurements, and the results are presented in terms of the observed excitation energies and spins. Moreover, the reaction mechanism is qualitatively discussed as a transfer of a clusterlike particle within a distorted-wave Born approximation framework. The results indicate that cluster-transfer reactions can be described well as a direct process and that they can be an efficient method to investigate the structure of neutron-rich nuclei at medium-high excitation energies and spins.

  7. Neutron Capture Gamma-Ray Libraries for Nuclear Applications

    NASA Astrophysics Data System (ADS)

    Sleaford, B. W.; Firestone, R. B.; Summers, N.; Escher, J.; Hurst, A.; Krticka, M.; Basunia, S.; Molnar, G.; Belgya, T.; Revay, Z.; Choi, H. D.

    2011-06-01

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. This can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research Project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. We are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.

  8. Neutron Capture Gamma-Ray Libraries for Nuclear Applications

    SciTech Connect

    Sleaford, B W; Firestone, R B; Summers, N; Escher, J; Hurst, A; Krticka, M; Basunia, S; Molnar, G; Belgya, T; Revay, Z; Choi, H D

    2010-11-04

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. this can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. They are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.

  9. Neutron Capture Gamma-Ray Libraries for Nuclear Applications

    SciTech Connect

    Sleaford, B. W.; Summers, N.; Escher, J.; Firestone, R. B.; Basunia, S.; Hurst, A.; Krticka, M.; Molnar, G.; Belgya, T.; Revay, Z.; Choi, H. D.

    2011-06-28

    The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. This can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research Project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. We are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.

  10. Beam shaping assembly of a D-T neutron source for BNCT and its dosimetry simulation in deeply-seated tumor

    NASA Astrophysics Data System (ADS)

    Faghihi, F.; Khalili, S.

    2013-08-01

    This article involves two aims for BNCT. First case includes a beam shaping assembly estimation for a D-T neutron source to find epi-thermal neutrons which are the goal in the BNCT. Second issue is the percent depth dose calculation in the adult Snyder head phantom. Monte-Carlo simulations and verification of a suggested beam shaping assembly (including internal neutron multiplier, moderator, filter, external neutron multiplier, collimator, and reflector dimensions) for thermalizing a D-T neutron source as well as increasing neutron flux are carried out and our results are given herein. Finally, we have simulated its corresponding doses for treatment planning of a deeply-seated tumor.

  11. Water Calibration Measurements for Neutron Radiography: Application to Water Content Quantification in Porous Media

    SciTech Connect

    Kang, Misun; Bilheux, Hassina Z; Voisin, Sophie; Cheng, Chu-lin; Perfect, Edmund; Horita, Juske; Warren, Jeffrey

    2013-04-01

    Using neutron radiography, the measurement of water thickness was performed using aluminum (Al) water calibration cells at the High Flux Isotope Reactor (HFIR) Cold-Guide (CG) 1D neutron imaging facility at Oak Ridge National Laboratory, Oak Ridge, TN, USA. Calibration of water thickness is an important step to accurately measure water contents in samples of interest. Neutron attenuation by water does not vary linearly with thickness mainly due to beam hardening and scattering effects. Transmission measurements for known water thicknesses in water calibration cells allow proper correction of the underestimation of water content due to these effects. As anticipated, strong scattering effects were observed for water thicknesses greater than 2 mm when the water calibration cells were positioned close to the face of the detector / scintillator (0 and 2.4 cm away, respectively). The water calibration cells were also positioned 24 cm away from the detector face. These measurements resulted in less scattering and this position (designated as the sample position) was used for the subsequent experimental determination of the neutron attenuation coefficient for water. Neutron radiographic images of moist Flint sand in rectangular and cylindrical containers acquired at the sample position were used to demonstrate the applicability of the water calibration. Cumulative changes in the water volumes within the sand columns during monotonic drainage determined by neutron radiography were compared with those recorded by direct reading from a burette connected to a hanging water column. In general, the neutron radiography data showed very good agreement with those obtained volumetrically using the hanging water-column method. These results allow extension of the calibration equation to the quantification of unknown water contents within other samples of porous media.

  12. Water calibration measurements for neutron radiography: Application to water content quantification in porous media

    NASA Astrophysics Data System (ADS)

    Kang, M.; Bilheux, H. Z.; Voisin, S.; Cheng, C. L.; Perfect, E.; Horita, J.; Warren, J. M.

    2013-04-01

    Using neutron radiography, the measurement of water thickness was performed using aluminum (Al) water calibration cells at the High Flux Isotope Reactor (HFIR) Cold-Guide (CG) 1D neutron imaging facility at Oak Ridge National Laboratory, Oak Ridge, TN, USA. Calibration of water thickness is an important step to accurately measure water contents in samples of interest. Neutron attenuation by water does not vary linearly with thickness mainly due to beam hardening and scattering effects. Transmission measurements for known water thicknesses in water calibration cells allow proper correction of the underestimation of water content due to these effects. As anticipated, strong scattering effects were observed for water thicknesses greater than 0.2 cm when the water calibration cells were positioned close to the face of the detector/scintillator (0 and 2.4 cm away, respectively). The water calibration cells were also positioned 24 cm away from the detector face. These measurements resulted in less scattering and this position (designated as the sample position) was used for the subsequent experimental determination of the neutron attenuation coefficient for water. Neutron radiographic images of moist Flint sand in rectangular and cylindrical containers acquired at the sample position were used to demonstrate the applicability of the water calibration. Cumulative changes in the water volumes within the sand columns during monotonic drainage determined by neutron radiography were compared with those recorded by direct reading from a burette connected to a hanging water column. In general, the neutron radiography data showed very good agreement with those obtained volumetrically using the hanging water-column method. These results allow extension of the calibration equation to the quantification of unknown water contents within other samples of porous media.

  13. Nonpropulsive applications of ion beams. [electric propulsion technology utilization

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.

    1976-01-01

    This paper describes the results of an investigation of the nonpropulsive applications of electric propulsion technology. Eight centimeter ion beam sources utilizing xenon and argon have been developed that operate over a wide range of beam energies and currents. Three types of processes have been studied - sputter deposition, ion beam machining, and ion beam surface texturing. The broad range of source operating conditions allows optimum sputter deposition of various materials. An ion beam source has also been used to ion mill laser reflection holograms using photoresist patterns on silicon. Ion beam texturing has been tried with many materials and has a multitude of potential applications.

  14. Union of Compact Accelerator-Driven Neutron Sources (UCANS) I & II Neutron applications laboratory for ESS-Bilbao

    NASA Astrophysics Data System (ADS)

    Terrón, S.; Magán, M.; Sordo, F.; Ghiglino, A.; Mart«ınez, F.; Bermejo, F. J.; Perlado, J. M.

    The ESS-Bilbao Accelerator Center site at Lejoa UPV/EHU campus will be provided with a proton accelerator up to 300-400 MeV. In the first construction phase, a beam extraction will be set at the end of the DTL, which will produce a 50 MeV proton beam with an average current of 2.25 mA and 1.5 ms pulses at a frequency of 20 Hz. These beam characteristics allow to configure a low intensity neutron source based on Be (p, n) reactions, which enables experimentation with cold neutrons similar to that of LENS. The total beam power will be 112 kW, so the configuration of the neutron production target will be based on a rotating disk of beryllium slabs facing the beam on one side and a cryogenic methane moderator on the other, with the target-moderator system surrounded by a beryllium reflector. In this paper, first estimates will be presented for thermomechanical conditions of the target cooling scheme, neutron source intensities, and cold neutron pulses.

  15. An application of the neutron television fluoroscopic system to neutron computed tomography

    NASA Astrophysics Data System (ADS)

    Fujine, Shigenori; Yoneda, Kenji; Kanda, Keiji

    1984-10-01

    Recently the real-time neutron radiography system of the Kyoto University Reactor (KUR) has been developed and practically applied to penetrating the side plates of the MTR type reactor fuels and investigation of moving objects. In this paper an application of the KUR neutron TV system to neutron computed tomography (NCT) is described. By using the NTV system, projection data can be acquired in a single measurement and simultaneously the projection image can be observed on a CRT monitor. The Fourier-convolution technique is used to produce the reconstructed image and its image has a good enough quality for revealing water in a small hole of 1.5 mm in diameter.

  16. Coulomb Excitation of Isolde Neutron-Rich Beams Along the Z = 28 Chain

    NASA Astrophysics Data System (ADS)

    van Duppen, P.

    2008-04-01

    Results from the recently commissioned REX-ISOLDE (CERN) post-accelerator facility are reported. Coulomb excitation with purified beams of neutron-rich zinc isotopes (including N = 50 80Zn) and with isomeric beams of copper isotopes were performed using the MINIBALL germanium array. The data are compared to large scale shell-model calculations and provide information on the fragility of the N = 40 sub-shell closure, stability of the N = 50 shell closure and the onset of deformation in this region of the nuclear chart. The specific nuclear structure around the Z = 28, N = 40 shells make Coulomb excitation an experimental tool for induced depopulation of a nuclear isomer. The presentation is concluded with a brief overview of the REX-ISOLDE physics program and with an outlook towards the intensity and energy upgrade of the ISOLDE complex (so-called HIE-ISOLDE).

  17. Biophysical applications of neutron Compton scattering

    NASA Astrophysics Data System (ADS)

    Wanderlingh, U. N.; Albergamo, F.; Hayward, R. L.; Middendorf, H. D.

    Neutron Compton scattering (NCS) can be applied to measuring nuclear momentum distributions and potential parameters in molecules of biophysical interest. We discuss the analysis of NCS spectra from peptide models, focusing on the characterisation of the amide proton dynamics in terms of the width of the H-bond potential well, its Laplacian, and the mean kinetic energy of the proton. The Sears expansion is used to quantify deviations from the high-Q limit (impulse approximation), and line-shape asymmetry parameters are evaluated in terms of Hermite polynomials. Results on NCS from selectively deuterated acetanilide are used to illustrate this approach.

  18. Separation of beam and electrons in the spallation neutron source H{sup -} ion source

    SciTech Connect

    Whealton, J.H.; Raridon, R.J.; Leung, K.N.

    1997-12-01

    The Spallation Neutron Source (SNS) requires an ion source producing an H{sup {minus}} beam with a peak current of 35mA at a 6.2 percent duty factor. For the design of this ion source, extracted electrons must be transported and dumped without adversely affecting the H{sup {minus}} beam optics. Two issues are considered: (1) electron containment transport and controlled removal; and (2) first-order H{sup {minus}} beam steering. For electron containment, various magnetic, geometric and electrode biasing configurations are analyzed. A kinetic description for the negative ions and electrons is employed with self-consistent fields obtained from a steady-state solution to Poisson`s equation. Guiding center electron trajectories are used when the gyroradius is sufficiently small. The magnetic fields used to control the transport of the electrons and the asymmetric sheath produced by the gyrating electrons steer the ion beam. Scenarios for correcting this steering by split acceleration and focusing electrodes will be considered in some detail.

  19. Performance of a New Composite Single-Crystal Filtered Thermal Neutron Beam for Neutron Capture Therapy Research at the University of Missouri

    SciTech Connect

    John D. Brockman; David W. Nigg; M. Frederick Hawthorne; Charles McKibben

    2008-11-01

    The University of Missouri (MU) Institute for Nano and Molecular Medicine, the Idaho National Laboratory (INL) and the University of Missouri Research Reactor (MURR) have undertaken a new collaborative research initiative to further the development of improved boron delivery agents for BNCT. The first step of this effort has involved the design and construction of a new thermal neutron beam irradiation facility for cell and small-animal radiobological research at the MURR. In this paper we present the beamline design with the results of pertinent neutronic design calculations. Results of neutronic performance measurements, initiated in February 2008, will also be available for inclusion in the final paper. The new beam will be located in an existing 152.4 mm (6’) diameter MURR beam tube extending from the core to the right in Figure 1. The neutron beam that emanates from the berylium reflector around the reactor is filtered with single-crystal silicon and single-crystal bismuth segments to remove high energy, fission spectrum neutrons and reactor gamma ray contamination. The irradiation chamber is downstream of the bismuth filter section, and approximately 3.95 m from the central axis of the reactor. There is sufficient neutron flux available from the MURR at its rated power of 10 MW to avoid the need for cryogenic cooling of the crystals. The MURR operates on average 150 hours per week, 52 weeks a year. In order to take advantage of 7800 hours of operation time per year the small animal BNCT facility will incorparate a shutter constucuted of boral, lead, steel and polyethylene that will allow experimenters to access the irradiation chamber a few minutes after irradiation. Independent deterministic and stochastic models of the coupled reactor core and beamline were developed using the DORT two-dimensional radiation transport code and the MCNP-5 Monte Carlo code, respectively. The BUGLE-80 47-neutron, 20-gamma group cross section library was employed for the DORT

  20. Spectrum and density of neutron flux in the irradiation beam line no. 3 of the IBR-2 reactor

    NASA Astrophysics Data System (ADS)

    Shabalin, E. P.; Verkhoglyadov, A. E.; Bulavin, M. V.; Rogov, A. D.; Kulagin, E. N.; Kulikov, S. A.

    2015-03-01

    Methodology and results of measuring the differential density of the neutron flux in irradiation beam line no. 3 of the IBR-2 reactor using neutron activation analysis (NAA) are presented in the paper. The results are compared to the calculation performed on the basis of the 3D MCNP model. The data that are obtained are required to determine the integrated radiation dose of the studied samples at various distances from the reactor.

  1. Investigation of the combined effect of neutron irradiation and electron beam exposure on pure tungsten

    NASA Astrophysics Data System (ADS)

    Van Renterghem, W.; Uytdenhouwen, I.

    2016-08-01

    Pure tungsten samples were neutron irradiated in the BR2 reactor of SCK·CEN to fluences of 1.47 × 1020 n/cm2 and 4.74 × 1020 n/cm2 at 300 °C under Helium atmosphere and exposed to the electron beam of the Judith 1 installation The effect of these treatments on the defect structure was studied with transmission electron microscopy. In the irradiated samples the defect structure in the bulk is compared to the structure at the surface. The neutron irradiation created a large amount of a/2‹111› type dislocation loops forming dislocation rafts. The loop density increased from 8.5 × 1021/m³ to 9 × 1022/m³ with increasing dose, while the loop size decreased from 5.2 nm to 3.5 nm. The electron beam exposure induced significant annealing of the defects and almost all of the dislocation loops were removed. The number of line dislocations in that area increased as a result of the thermal stresses from the thermal shock.

  2. Active beam position stabilization of pulsed lasers for long-distance ion profile diagnostics at the Spallation Neutron Source (SNS).

    PubMed

    Hardin, Robert A; Liu, Yun; Long, Cary; Aleksandrov, Alexander; Blokland, Willem

    2011-02-14

    A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 μrad (horizontal) to 4 μrad (vertical), corresponding to beam drifts of only 0.5 mm × 1 mm at the furthest measurement station located 250 meters away from the light source.

  3. Active beam position stabilization of pulsed lasers for long-distance ion profile diagnostics at the Spallation Neutron Source (SNS)

    SciTech Connect

    Hardin, Robert A; Liu, Yun; Long, Cary D; Aleksandrov, Alexander V; Blokland, Willem

    2011-01-01

    A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 rad (horizontal) to 4 rad (vertical), corresponding to beam drifts of only 0.5 mm 1 mm at the furthest measurement station located 250 meters away from the light source.

  4. Delayed Cerebral Radiation Necrosis after Neutron Beam Radiation of a Parotid Adenocarcinoma: A Case Report and Review of the Literature

    PubMed Central

    Hong, Christopher S.; Gokozan, Hamza N.; Otero, José J.; Guiou, Michael; Elder, J. Bradley

    2014-01-01

    Cerebral radiation necrosis (CRN) is a well described possible complication of radiation for treatment of intracranial pathology. However, CRN as sequelae of radiation to extracranial sites is rare. Neutron beam radiation is a highly potent form of radiotherapy that may be used to treat malignant tumors of the salivary glands. This report describes a patient who underwent neutron beam radiation for a parotid adenocarcinoma and who developed biopsy-confirmed temporal lobe radiation necrosis thirty months later. This represents the longest time interval described to date, from initial neutron radiation for extracranial pathology to development of CRN. Two other detailed case studies exist in the literature and are described in this report. These reports as well as our patient's case are reviewed, and additional recommendations are made to minimize the development of CRN after extracranial neutron beam radiation. Physicians should include the possible diagnosis of CRN in any patient with new neurologic signs or symptoms and a history of head and neck radiation that included planned fields extending to the base of the skull. Counseling of patients prior to neutron beam radiation should include potential neurologic complications associated with CRN and risks of treatment for CRN including neurosurgical intervention. PMID:25349750

  5. Delayed cerebral radiation necrosis after neutron beam radiation of a parotid adenocarcinoma: a case report and review of the literature.

    PubMed

    Hong, Christopher S; Gokozan, Hamza N; Otero, José J; Guiou, Michael; Elder, J Bradley

    2014-01-01

    Cerebral radiation necrosis (CRN) is a well described possible complication of radiation for treatment of intracranial pathology. However, CRN as sequelae of radiation to extracranial sites is rare. Neutron beam radiation is a highly potent form of radiotherapy that may be used to treat malignant tumors of the salivary glands. This report describes a patient who underwent neutron beam radiation for a parotid adenocarcinoma and who developed biopsy-confirmed temporal lobe radiation necrosis thirty months later. This represents the longest time interval described to date, from initial neutron radiation for extracranial pathology to development of CRN. Two other detailed case studies exist in the literature and are described in this report. These reports as well as our patient's case are reviewed, and additional recommendations are made to minimize the development of CRN after extracranial neutron beam radiation. Physicians should include the possible diagnosis of CRN in any patient with new neurologic signs or symptoms and a history of head and neck radiation that included planned fields extending to the base of the skull. Counseling of patients prior to neutron beam radiation should include potential neurologic complications associated with CRN and risks of treatment for CRN including neurosurgical intervention. PMID:25349750

  6. Neutron Transport Characteristics of a Nuclear Reactor Based Dynamic Neutron Imaging System

    SciTech Connect

    Khaial, Anas M.; Harvel, Glenn D.; Chang, Jen-Shih

    2006-07-01

    An advanced dynamic neutron imaging system has been constructed in the McMaster Nuclear Reactor (MNR) for nondestructive testing and multi-phase flow studies in energy and environmental applications. A high quality neutron beam is required with a thermal neutron flux greater than 5.0 x 10{sup 6} n/cm{sup 2}-s and a collimation ratio of 120 at image plane to promote high-speed neutron imaging up to 2000 frames per second. Neutron source strength and neutron transport have been experimentally and numerically investigated. Neutron source strength at the beam tube entrance was evaluated experimentally by measuring the thermal and fast neutron fluxes, and simple analytical neutron transport calculations were performed based upon these measured neutron fluxes to predict facility components in accordance with high-speed dynamic neutron imaging and operation safety requirements. Monte-Carlo simulations (using MCNP-4B code) with multiple neutron energy groups have also been used to validate neutron beam parameters and to ensure shielding capabilities of facility shutter and cave walls. Neutron flux distributions at the image plane and the neutron beam characteristics were experimentally measured by irradiating a two-dimensional array of Copper foils and using a real-time neutron radiography system. The neutron image characteristics -- such as neutron flux, image size, beam quality -- measured experimentally and predicted numerically for beam tube, beam shutter and radiography cave are compared and discussed in detail in this paper. The experimental results show that thermal neutron flux at image plane is nearly uniform over an imaging area of 20.0-cm diameter and its magnitude ranges from 8.0 x 10{sup 6} - 1.0 x 10{sup 7} n/cm{sup 2}-sec while the neutron-to-gamma ratio is 6.0 x 10{sup 5} n/cm{sup 2}-{mu}Sv. (authors)

  7. Deuterated polyethylene coatings for ultra-cold neutron applications

    SciTech Connect

    Brenner, Th.; Geltenbort, P.; Fierlinger, P.; Gutsmiedl, E.; Hollering, A.; Petzoldt, G.; Ruhstorfer, D.; Stuiber, St.; Taubenheim, B.; Windmayer, D.; Lauer, T.; Schroffenegger, J.; Zechlau, T.; Seemann, K. M.; Soltwedel, O.

    2015-09-21

    We report on the fabrication and use of deuterated polyethylene as a coating material for ultra-cold neutron (UCN) storage and transport. The Fermi potential has been determined to be 214 neV, and the wall loss coefficient η is 1.3 × 10{sup 4} per wall collision. The coating technique allows for a wide range of applications in this field of physics. In particular, flexible and quasi-massless UCN guides with slit-less shutters and seamless UCN storage volumes become possible. These properties enable the use in next-generation measurements of the electric dipole moment of the neutron.

  8. Neutrons against cancer

    NASA Astrophysics Data System (ADS)

    Dovbnya, A. N.; Kuplennikov, E. L.; Kandybey, S. S.; Krasiljnikov, V. V.

    2014-09-01

    The review is devoted to the analysis and generalization of the research carried out during recent years in industrially advanced countries on the use of fast, epithermal, and thermal neutrons for therapy of malignant tumors. Basic facilities for neutron production used for cancer treatment are presented. Optimal parameters of therapeutic beams are described. Techniques using neutrons of different energy regions are discussed. Results and medical treatment efficiency are given. Comparison of the current state of neutron therapy of tumors and alternative treatments with beams of protons and carbon ions has been conducted. Main attention is given to the possibility of the practical use of accumulated experience of application of neutron beams for cancer therapy.

  9. New spallation neutron sources, their performance and applications

    SciTech Connect

    Not Available

    1985-01-01

    Pulsed spallation sources now operating in the world are at the KEK Laboratory in Japan (the KENS source), at Los Alamos National Laboratory (WNR) and at Argonne National Laboratory (IPNS), both the latter being in the US. The Intense Pulsed Neutron Source (IPNS) is currently the world's most intense source with a peak neutron flux of 4 x 10/sup 14/ n cm/sup -2/s/sup -1/ at a repetition rate of 30 Hz, and globally producing approx. 1.5 x 10/sup 15/ n/sec. Present pulsed sources are still relatively weak compared to their potential. In 1985 the Rutherford Spallation Neutron Source will come on line, and eventually be approx. 30 more intense than the present IPNS. Later, in 1986 the WNR/PSR option at Los Alamos will make that facility of comparable intensity, while a subcritical fission booster at IPNS will keep IPNS competitive. These new sources will expand the applications of pulsed neutrons but are still based on accelerators built for other scientific purposes, usually nuclear or high-energy physics. Accelerator physicists are now designing machines expressly for spallation neutron research, and the proton currents attainable appear in the milliamps. (IPNS now runs at 0.5 GeV and 14 ..mu..A). Such design teams are at the KFA Laboratory Julich, Argonne National Laboratory and KEK. Characteristics, particularly the different time structure of the pulses, of these new sources will be discussed. S

  10. Neutron capture therapies

    SciTech Connect

    Yanch, J.C.; Shefer, R.E.; Klinkowstein, R.E.

    1999-11-02

    In one embodiment there is provided an application of the {sup 10}B(n,{alpha}){sup 7}Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  11. Neutron capture therapies

    DOEpatents

    Yanch, Jacquelyn C.; Shefer, Ruth E.; Klinkowstein, Robert E.

    1999-01-01

    In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

  12. Dosimetry measurements of x-ray and neutron radiation levels near the shuttle and end beam dump at the advanced test accelerator: Beam Research Program

    SciTech Connect

    Gibson, T.A. Jr.; Struve, K.W.; Lindgren, R.A.

    1987-01-01

    Electron beams as a source of directed energy are under study at the Lawrence Livermore National Laboratory (LLNL). An intense 10-kA, 50-MeV, 50-ns full-width half-maximum, pulsed electron beam is generated by the prototype Advanced Test Accelerator (ATA) at the Laboratory's Site 300. Whenever the electron beam is stopped in materials, intense radiation is generated. Estimates based on available data in the literature show that for materials such as lead, photon radiation (x ray, gamma, bremsstrahlung) levels can be as large as 10/sup 4/ roentgens per pulse at 1 m in the zero-degree direction (i.e., the electron-beam direction). Neutrons, which are emitted isotropically, are produced at a level of 10/sup 13/ n/m/sup 2/ per pulse. Depending upon the number of pulses and the shielding geometry, the accumulated dose is potentially lethal to personnel and potentially damaging to instrumentation that may be used for diagnostics. To provide shielding for minimizing the risk of exposure to personnel and radiation damage to instrumentation, it is important to determine the x-ray and neutron radiation environment near beamline components such as the beam shuttle dump and beam stop. Photon and neutron dosimetry measurements were performed around the beam shuttle dump on January 9, 1985, and near the carbon beam stop at the end of the beamline before the entrance to the diagnostic tunnel on April 12 and December 23, 1985. These measurements together with simple rule-of-thumb estimates and Monte Carlo electron-photon shower calculations of the absorbed dose are presented in this report. 17 refs., 14 figs., 13 tabs.

  13. Application of neutron diffraction in characterization of texture evolution during high-temperature creep in magnesium alloys

    SciTech Connect

    Vogel, Sven C; Sediako, Dimitry; Shook, S; Sediako, A

    2010-01-01

    A good combination of room-temperature and elevated temperature strength and ductility, good salt-spray corrosion resistance and exceUent diecastability are frequently among the main considerations in development of a new alloy. Unfortunately, there has been much lesser effort in development of wrought-stock alloys for high temperature applications. Extrudability and high temperature performance of wrought material becomes an important factor in an effort to develop new wrought alloys and processing technologies. This paper shows some results received in creep testing and studies of in-creep texture evolution for several wrought magnesium alloys developed for use in elevated-temperature applications. These studies were performed using E3 neutron spectrometer of the Canadian Neutron Beam Centre in Chalk River, ON, and HIPPO time-of-flight (TOF) spectrometer at Los Alamos Neutron Science Center, NM.

  14. SU-E-T-567: Neutron Dose Equivalent Evaluation for Pencil Beam Scanning Proton Therapy with Apertures

    SciTech Connect

    Geng, C; Schuemann, J; Moteabbed, M; Paganetti, H

    2015-06-15

    Purpose: To determine the neutron contamination from the aperture in pencil beam scanning during proton therapy. Methods: A Monte Carlo based proton therapy research platform TOPAS and the UF-series hybrid pediatric phantoms were used to perform this study. First, pencil beam scanning (PBS) treatment pediatric plans with average spot size of 10 mm at iso-center were created and optimized for three patients with and without apertures. Then, the plans were imported into TOPAS. A scripting method was developed to automatically replace the patient CT with a whole body phantom positioned according to the original plan iso-center. The neutron dose equivalent was calculated using organ specific quality factors for two phantoms resembling a 4- and 14-years old patient. Results: The neutron dose equivalent generated by the apertures in PBS is 4–10% of the total neutron dose equivalent for organs near the target, while roughly 40% for organs far from the target. Compared to the neutron dose equivalent caused by PBS without aperture, the results show that the neutron dose equivalent with aperture is reduced in the organs near the target, and moderately increased for those organs located further from the target. This is due to the reduction of the proton dose around the edge of the CTV, which causes fewer neutrons generated in the patient. Conclusion: Clinically, for pediatric patients, one might consider adding an aperture to get a more conformal treatment plan if the spot size is too large. This work shows the somewhat surprising fact that adding an aperture for beam scanning for facilities with large spot sizes reduces instead of increases a potential neutron background in regions near target. Changran Geng is supported by the Chinese Scholarship Council (CSC) and the National Natural Science Foundation of China (Grant No. 11475087)

  15. Cold atomic beam ion source for focused ion beam applications

    SciTech Connect

    Knuffman, B.; Steele, A. V.; McClelland, J. J.

    2013-07-28

    We report measurements and modeling of an ion source that is based on ionization of a laser-cooled atomic beam. We show a high brightness and a low energy spread, suitable for use in next-generation, high-resolution focused ion beam systems. Our measurements of total ion current as a function of ionization conditions support an analytical model that also predicts the cross-sectional current density and spatial distribution of ions created in the source. The model predicts a peak brightness of 2 × 10{sup 7} A m{sup −2} sr{sup −1} eV{sup −1} and an energy spread less than 0.34 eV. The model is also combined with Monte-Carlo simulations of the inter-ion Coulomb forces to show that the source can be operated at several picoamperes with a brightness above 1 × 10{sup 7} A m{sup −2} sr{sup −1} eV{sup −1}. We estimate that when combined with a conventional ion focusing column, an ion source with these properties could focus a 1 pA beam into a spot smaller than 1 nm. A total current greater than 5 nA was measured in a lower-brightness configuration of the ion source, demonstrating the possibility of a high current mode of operation.

  16. Forecasting the effect of neutron beam divergence on the quality of tomographic images

    NASA Astrophysics Data System (ADS)

    de Almeida, G. L.; Silvani, M. I.; Furieri, R. A.; Gonçalves, M. J.; Lopes, R. T.

    2007-08-01

    The impact of the divergence of a neutron beam emitted by a surface source on the quality of 2D tomographic images has been assessed through a computer code specially written for this purpose. It generates position spectra used as projections for the final image reconstruction, based on the geometric and physical properties of the sample and its positioning in the system, detector resolution, beam divergence expressed by the width of its rocking curve, and on the counting statistics. Such a forecast is important in order to evaluate whether measures to reduce the divergence are worthwhile at all, before efforts and investment to design and manufacture collimators or purchase them are done. It also helps to optimize parameters prior to performing the measurements with real imaging systems. Simulated images of some test objects obtained under different beam divergences have been compared with experimentally acquired ones, using an imaging system equipped with a position sensitive detector (PSD). Further simulations performed under a constant divergence, to evaluate the impact of the total rotation angle applied to the object, have also been done, showing that the developed simulator is an useful tool to plan experiments and to optimize parameters of imaging systems of this kind.

  17. Neutron spectrum measurements at a radial beam port of the NUR research reactor using a Bonner spheres spectrometer.

    PubMed

    Mazrou, H; Nedjar, A; Seguini, T

    2016-08-01

    This paper describes the measurement campaign held around the neutron radiography (NR) facility of the Algerian 1MW NUR research reactor. The main objective of this work is to characterize accurately the neutron beam provided at one of the radial channels of the NUR research reactor taking benefit of the acquired CRNA Bonner spheres spectrometer (BSS). The specific objective was to improve the image quality of the NR facility. The spectrometric system in use is based on a central spherical (3)He thermal neutron proportional counter combined with high density polyethylene spheres of different diameters ranging from 3 to 12in. This counting system has good gamma ray discrimination and is able to cover an energy range from thermal to 20MeV. The measurements were performed at the sample distance of 0.6m from the beam port and at a height of 1.2m from the facility floor. During the BSS measurements, the reactor was operating at low power (100W) to avoid large dead times, pulse pileup and high level radiation exposures, in particular, during spheres handling. Thereafter, the neutron spectrum at the sample position was unfolded by means of GRAVEL and MAXED computer codes. The thermal, epithermal and fast neutron fluxes, the total neutron flux, the mean energy and the Cadmium ratio (RCd) were provided. A sensitivity analysis was performed taking into account various defaults spectra and ultimately a different response functions in the unfolding procedure. Overall, from the obtained results it reveals, unexpectedly, that the measured neutron spectrum at the sample position of the neutron radiography of the NUR reactor is being harder with a predominance of fast neutrons (>100keV) by about 60%. Finally, those results were compared to previous and more recent measurements obtained by activation foils detectors. The agreement was fairly good highlighting thereby the consistency of our findings. PMID:27203706

  18. Neutron spectrum measurements at a radial beam port of the NUR research reactor using a Bonner spheres spectrometer.

    PubMed

    Mazrou, H; Nedjar, A; Seguini, T

    2016-08-01

    This paper describes the measurement campaign held around the neutron radiography (NR) facility of the Algerian 1MW NUR research reactor. The main objective of this work is to characterize accurately the neutron beam provided at one of the radial channels of the NUR research reactor taking benefit of the acquired CRNA Bonner spheres spectrometer (BSS). The specific objective was to improve the image quality of the NR facility. The spectrometric system in use is based on a central spherical (3)He thermal neutron proportional counter combined with high density polyethylene spheres of different diameters ranging from 3 to 12in. This counting system has good gamma ray discrimination and is able to cover an energy range from thermal to 20MeV. The measurements were performed at the sample distance of 0.6m from the beam port and at a height of 1.2m from the facility floor. During the BSS measurements, the reactor was operating at low power (100W) to avoid large dead times, pulse pileup and high level radiation exposures, in particular, during spheres handling. Thereafter, the neutron spectrum at the sample position was unfolded by means of GRAVEL and MAXED computer codes. The thermal, epithermal and fast neutron fluxes, the total neutron flux, the mean energy and the Cadmium ratio (RCd) were provided. A sensitivity analysis was performed taking into account various defaults spectra and ultimately a different response functions in the unfolding procedure. Overall, from the obtained results it reveals, unexpectedly, that the measured neutron spectrum at the sample position of the neutron radiography of the NUR reactor is being harder with a predominance of fast neutrons (>100keV) by about 60%. Finally, those results were compared to previous and more recent measurements obtained by activation foils detectors. The agreement was fairly good highlighting thereby the consistency of our findings.

  19. Generation and application of bessel beams in electron microscopy.

    PubMed

    Grillo, Vincenzo; Harris, Jérémie; Gazzadi, Gian Carlo; Balboni, Roberto; Mafakheri, Erfan; Dennis, Mark R; Frabboni, Stefano; Boyd, Robert W; Karimi, Ebrahim

    2016-07-01

    We report a systematic treatment of the holographic generation of electron Bessel beams, with a view to applications in electron microscopy. We describe in detail the theory underlying hologram patterning, as well as the actual electron-optical configuration used experimentally. We show that by optimizing our nanofabrication recipe, electron Bessel beams can be generated with relative efficiencies reaching 37±3%. We also demonstrate by tuning various hologram parameters that electron Bessel beams can be produced with many visible rings, making them ideal for interferometric applications, or in more highly localized forms with fewer rings, more suitable for imaging. We describe the settings required to tune beam localization in this way, and explore beam and hologram configurations that allow the convergences and topological charges of electron Bessel beams to be controlled. We also characterize the phase structure of the Bessel beams generated with our technique, using a simulation procedure that accounts for imperfections in the hologram manufacturing process. PMID:27203186

  20. Pulsed and monoenergetic beams for neutron cross-section measurements using activation and scattering techniques at Triangle Universities Nuclear Laboratory

    NASA Astrophysics Data System (ADS)

    Hutcheson, A.; Angell, C. T.; Becker, J. A.; Boswell, M.; Crowell, A. S.; Dashdorj, D.; Fallin, B.; Fotiades, N.; Howell, C. R.; Karwowski, H. J.; Kelley, J. H.; Kiser, M.; Macri, R. A.; Nelson, R. O.; Pedroni, R. S.; Tonchev, A. P.; Tornow, W.; Vieira, D. J.; Weisel, G. J.; Wilhelmy, J. B.

    2007-08-01

    In support of the Stewardship Science Academic Alliances initiative, an experimental program has been developed at Triangle Universities Nuclear Laboratory (TUNL) to measure (n,xn) cross-sections with both in-beam and activation techniques with the goal of improving the partial cross-section database for the NNSA Stockpile Stewardship Program. First experimental efforts include excitation function measurements on 235,238U and 241Am using pulsed and monoenergetic neutron beams with En = 5-15 MeV. Neutron-induced partial cross-sections were measured by detecting prompt γ rays from the residual nuclei using various combinations of clover and planar HPGe detectors in the TUNL shielded neutron source area. Complimentary activation measurements using DC neutron beams have also been performed in open geometry in our second target area. The neutron-induced activities were measured in the TUNL low-background counting area. In this presentation, we include detailed information about the irradiation procedures and facilities and preliminary data on first measurements using this capability.

  1. Ramping up the Spallation Neutron Source beam power with the H{sup -} source using 0 mg Cs/day

    SciTech Connect

    Stockli, M. P.; Han, B.; Murray, S. N.; Pennisi, T. R.; Santana, M.; Welton, R. F.

    2010-02-15

    This paper describes the ramp up of the beam power for the Spallation Neutron Source by ramping up the pulse length, the repetition rate, and the beam current emerging from the H{sup -} source. Starting out with low repetition rates ({<=}10 Hz) and short pulse lengths ({<=}0.2 ms), the H{sup -} source and low-energy beam transport delivered from Lawrence Berkeley National Laboratory exceeded the requirements with almost perfect availability. This paper discusses the modifications that were required to exceed 0.2 ms pulse length and 0.2% duty factor with acceptable availability and performance. Currently, the source is supporting neutron production at 1 MW with 38 mA linac beam current at 60 Hz and 0.9 ms pulse length. The pulse length will be increased to {approx}1.1 ms to meet the requirements for neutron production with a power between 1 and 1.4 MW. A medium-energy beam transport (MEBT) beam current of 46 mA with a 5.4% duty factor has been demonstrated for 32 h. A 56 mA MEBT beam current with a 4.1% duty factor has been demonstrated for 20 min at the conclusion of a 12-day production run. This is close to the 59 mA needed for 3 MW neutron productions. Also notable is the Cs{sub 2}CrO{sub 4} cesium system, which dispenses {approx}10 mg of Cs during the startup of the ion source, sufficient for producing the required 38 mA for 4 weeks without significant degradation.

  2. Laser-driven x-ray and neutron source development for industrial applications of plasma accelerators

    NASA Astrophysics Data System (ADS)

    Brenner, C. M.; Mirfayzi, S. R.; Rusby, D. R.; Armstrong, C.; Alejo, A.; Wilson, L. A.; Clarke, R.; Ahmed, H.; Butler, N. M. H.; Haddock, D.; Higginson, A.; McClymont, A.; Murphy, C.; Notley, M.; Oliver, P.; Allott, R.; Hernandez-Gomez, C.; Kar, S.; McKenna, P.; Neely, D.

    2016-01-01

    Pulsed beams of energetic x-rays and neutrons from intense laser interactions with solid foils are promising for applications where bright, small emission area sources, capable of multi-modal delivery are ideal. Possible end users of laser-driven multi-modal sources are those requiring advanced non-destructive inspection techniques in industry sectors of high value commerce such as aerospace, nuclear and advanced manufacturing. We report on experimental work that demonstrates multi-modal operation of high power laser-solid interactions for neutron and x-ray beam generation. Measurements and Monte Carlo radiation transport simulations show that neutron yield is increased by a factor ~2 when a 1 mm copper foil is placed behind a 2 mm lithium foil, compared to using a 2 cm block of lithium only. We explore x-ray generation with a 10 picosecond drive pulse in order to tailor the spectral content for radiography with medium density alloy metals. The impact of using  >1 ps pulse duration on laser-accelerated electron beam generation and transport is discussed alongside the optimisation of subsequent bremsstrahlung emission in thin, high atomic number target foils. X-ray spectra are deconvolved from spectrometer measurements and simulation data generated using the GEANT4 Monte Carlo code. We also demonstrate the unique capability of laser-driven x-rays in being able to deliver single pulse high spatial resolution projection imaging of thick metallic objects. Active detector radiographic imaging of industrially relevant sample objects with a 10 ps drive pulse is presented for the first time, demonstrating that features of 200 μm size are resolved when projected at high magnification.

  3. Prompt gamma activation analysis of boron in reference materials using diffracted polychromatic neutron beam

    NASA Astrophysics Data System (ADS)

    Byun, S. H.; Sun, G. M.; Choi, H. D.

    2004-01-01

    Boron concentrations were analyzed for standard reference materials by prompt gamma activation analysis (PGAA). The measurements were performed at the SNU-KAERI PGAA facility installed at Hanaro, the research reactor of Korea Atomic Energy Research Institute (KAERI). The facility uses a diffracted polychromatic beam with a neutron flux of 7.9 × 10 7 n/cm 2 s. Elemental sensitivity for boron was calibrated from the prompt gamma-ray spectra of boric acid samples containing 2-45 μg boron. The sensitivity of 2131 cps/mg-B was obtained from the linearity of the boron peak count rate versus the boron mass. The detection limit for boron was estimated to be 67 ng from an empty sample bag spectrum for a counting time of 10,000 s. The measured boron concentrations for standard reference materials showed good consistency with the certified or information values.

  4. Off-axis dose equivalent due to secondary neutrons from uniform scanning proton beams during proton radiotherapy.

    PubMed

    Islam, M R; Collums, T L; Zheng, Y; Monson, J; Benton, E R

    2013-11-21

    The production of secondary neutrons is an undesirable byproduct of proton therapy and it is important to quantify the contribution from secondary neutrons to patient dose received outside the treatment volume. The purpose of this study is to investigate the off-axis dose equivalent from secondary neutrons experimentally using CR-39 plastic nuclear track detectors (PNTD) at ProCure Proton Therapy Center, Oklahoma City, OK. In this experiment, we placed several layers of CR-39 PNTD laterally outside the treatment volume inside a phantom and in air at various depths and angles with respect to the primary beam axis. Three different proton beams with max energies of 78, 162 and 226 MeV and 4 cm modulation width, a 5 cm diameter brass aperture, and a small snout located 38 cm from isocenter were used for the entire experiment. Monte Carlo simulations were also performed based on the experimental setup using a simplified snout configuration and the FLUKA Monte Carlo radiation transport code. The measured ratio of secondary neutron dose equivalent to therapeutic primary proton dose (H/D) ranged from 0.3 ± 0.08 mSv Gy−1 for 78 MeV proton beam to 37.4 ± 2.42 mSv Gy−1 for 226 MeV proton beam. Both experiment and simulation showed a similar decreasing trend in dose equivalent with distance to the central axis and the magnitude varied by a factor of about 2 in most locations. H/D was found to increase as the energy of the primary proton beam increased and higher H/D was observed at 135° compared to 45° and 90°. The overall higher H/D in air indicates the predominance of external neutrons produced in the nozzle rather than inside the body.

  5. NEUTRON AND GAMMA RAY DETECTION FOR BORDER SECURITY APPLICATIONS

    SciTech Connect

    Kouzes, Richard T.

    2010-05-21

    Countries around the world are deploying radiation detection instrumentation to interdict the illegal shipment of radioactive material crossing international borders. These efforts include deployments in the U.S. and in a number of other countries by governments and international organizations. Most deployed radiation portal monitor systems are based on plastic scintillator for gamma-ray detection and 3He tubes for neutron detection. The approach to this homeland security application, and lessons learned, are discussed.

  6. New applications of ORNL neutral beam injectors

    SciTech Connect

    Tsai, C. C.; Peng, Yueng Kay Martin

    1998-01-01

    The injection of energetic hydrogen and deuterium atoms has been used to heat plasmas in various fusion experimental devices including tokamaks, mirrors, and stellarators. The neutral beam injection is a proven plasma heating technique for increasing plasma densities, temperatures, and pressures. For this fusion endeavor, scientists at Oak Ridge National Laboratory (ORNL) have developed multimegawatt neutral beam injectors. Various ORNL injectors have been used for studying properties of beam-heated plasmas in Oak Ridge Tokamak (ORMAK), Impurity Study Experiment-B (ISX-B), Advanced Toroidal Facility (ATF), Princeton Large Torus (PLT), and Princeton Divertor Experiment (PDX) in the United States and in Small Tight Aspect Ratio Tokamak (START) in the United Kingdom. By using a 30-cm and 100-A ion source, each ORNL neutral beam injector is capable of injecting >1.5 MW of hydrogen atoms at 50-keV for a pulse length up to 0.5 s. For increasing plasma densities and raising plasma temperatures in START, one such injector was installed and commissioned during 1995. The initial goal was to provide an injected neutral beam power of more than 0.5 MW at a beam energy of 40 keV for 20 ms. Addition of a getter pump has allowed the beam power to be raised to 1 MW at 33 keV. Recent experiments have demonstrated that neutral beam heating can play a big role in raising plasma pressures to a record volume-average beta value over 30%. ORNL neutral beam injectors have been approved for plasma heating experiments on both the TJ-II stellarator at CIEMAT, Spain, and the Mega-Amp Spherical Tokamak (MAST) at Culham Science Centre (Culham). Two proven ORNL NE injectors are being installed at the TJ-II facility. Additional ORNL beam equipment is being used to implement two 5-s NE injectors at the MAST facility. In this paper, we report and discuss the progress and plans for these neutral beam activities.

  7. A compact post-acceleration beam chopper for a 4.5 MV Dynamitron pulsed neutron generator

    NASA Astrophysics Data System (ADS)

    Matsuyama, S.; Fujisawa, M.; Baba, M.; Iwasaki, T.; Iwasaki, S.; Sakamoto, R.; Hirakawa, N.; Sugiyama, K.

    1994-08-01

    A post-acceleration beam chopper (PACS) has been installed for a 4.5 MV Dynamitron accelerator to improve the energy resolution of neutron time-of-flight (TOF) experiments by shortening the duration of the ion beam pulses. The PACS sweeps the accelerated ion pulses across a chopping slit and eliminates the tails of the beam pulses. It operates sinusoidally at a frequency of 8 MHz with a maximum voltage of 10 kV peak to peak in synchronization with the accelerated ion pulses. The high voltage generator of the PACS was constructed of commercially available amplifiers and components, which realized easy maintenance and low cost. The PACS proved to be very effective to improve the pulse shape and has been applied for double-differential neutron emission cross section measurements.

  8. Active Interrogation Using Electronic Neutron Generators for Nuclear Safeguards Applications

    SciTech Connect

    Chichester, D. L.; Seabury, E. H.

    2009-03-10

    Active interrogation, a measurement technique which uses a radiation source to probe materials and generate unique signatures useful for characterizing those materials, is a powerful tool for assaying special nuclear material. The most commonly used technique for performing active interrogation is to use an electronic neutron generator as the probe radiation source. Exploiting the unique operating characteristics of these devices, including their monoenergetic neutron emissions and their ability to operate in pulsed modes, presents a number of options for performing prompt and delayed signature analyses using both photon and neutron sensors. A review of literature in this area shows multiple applications of the active neutron interrogation technique for performing nuclear nonproliferation measurements. Some examples include measuring the plutonium content of spent fuel, assaying plutonium residue in spent fuel hull claddings, assaying plutonium in aqueous fuel reprocessing process streams, and assaying nuclear fuel reprocessing facility waste streams to detect and quantify fissile material. This paper discusses the historical use of this technique and examines its context within the scope and challenges of next-generation nuclear fuel cycles and advanced concept nuclear fuel cycle facilities.

  9. Active Interrogation Using Electronic Neutron Generators for Nuclear Safeguards Applications

    SciTech Connect

    David L. Chichester; Edward H. Seabury

    2008-08-01

    Active interrogation, a measurement technique which uses a radiation source to probe materials and generate unique signatures useful for characterizing those materials, is a powerful tool for assaying special nuclear material. The most commonly used technique for performing active interrogation is to use an electronic neutron generator as the probe radiation source. Exploiting the unique operating characteristics of these devices, including their monoenergetic neutron emissions and their ability to operate in pulsed modes, presents a number of options for performing prompt and delayed signature analyses using both photon and neutron sensors. A review of literature in this area shows multiple applications of the active neutron interrogation technique for performing nuclear nonproliferation measurements. Some examples include measuring the plutonium content of spent fuel, assaying plutonium residue in spent fuel hull claddings, assaying plutonium in aqueous fuel reprocessing process streams, and assaying nuclear fuel reprocessing facility waste streams to detect and quantify fissile material. This paper discusses the historical use of this technique and examines its context within the scope and challenges of next-generation nuclear fuel cycles and advanced concept nuclear fuel cycle facilities.

  10. Liquid Li based neutron source for BNCT and science application.

    PubMed

    Horiike, H; Murata, I; Iida, T; Yoshihashi, S; Hoashi, E; Kato, I; Hashimoto, N; Kuri, S; Oshiro, S

    2015-12-01

    Liquid lithium (Li) is a candidate material for a target of intense neutron source, heat transfer medium in space engines and charges stripper. For a medical application of BNCT, epithermal neutrons with least energetic neutrons and γ-ray are required so as to avoid unnecessary doses to a patient. This is enabled by lithium target irradiated by protons at 2.5 MeV range, with utilizing the threshold reaction of (7)Li(p,n)(7)Be at 1.88 MeV. In the system, protons at 2.5 MeV penetrate into Li layer by 0.25 mm with dissipating heat load near the surface. To handle it, thin film flow of high velocity is important for stable operation. For the proton accelerator, electrostatic type of the Schnkel or the tandem is planned to be employed. Neutrons generated at 0.6 MeV are gently moderated to epithermal energy while suppressing accompanying γ-ray minimum by the dedicated moderator assembly.

  11. Liquid Li based neutron source for BNCT and science application.

    PubMed

    Horiike, H; Murata, I; Iida, T; Yoshihashi, S; Hoashi, E; Kato, I; Hashimoto, N; Kuri, S; Oshiro, S

    2015-12-01

    Liquid lithium (Li) is a candidate material for a target of intense neutron source, heat transfer medium in space engines and charges stripper. For a medical application of BNCT, epithermal neutrons with least energetic neutrons and γ-ray are required so as to avoid unnecessary doses to a patient. This is enabled by lithium target irradiated by protons at 2.5 MeV range, with utilizing the threshold reaction of (7)Li(p,n)(7)Be at 1.88 MeV. In the system, protons at 2.5 MeV penetrate into Li layer by 0.25 mm with dissipating heat load near the surface. To handle it, thin film flow of high velocity is important for stable operation. For the proton accelerator, electrostatic type of the Schnkel or the tandem is planned to be employed. Neutrons generated at 0.6 MeV are gently moderated to epithermal energy while suppressing accompanying γ-ray minimum by the dedicated moderator assembly. PMID:26253274

  12. Symmetric neutralized ion beams: Production, acceleration, propagation, and applications

    NASA Astrophysics Data System (ADS)

    Hicks, Nathaniel Kenneth

    This dissertation presents the first integrated experimental, computational, and theoretical research program on symmetric neutralized ion beams. A beam of this type is composed of positive and negative ions having equal charge-to-mass ratios, such that the beam has overall charge neutrality and its constituent ions respond symmetrically to electromagnetic forces. Under the right conditions, these beams may propagate undeflected across transverse magnetic fields due to beam polarization. Such propagation is studied here computationally, using a three-dimensional particle-in-cell code. Also, key theoretical differences between the propagation ability of these beams and that of beams consisting of positive ions and electrons are elucidated. An experimental method of producing a symmetric neutralized ion beam by merging together separate beams of positive and negative ions is demonstrated, and prototype collector hardware to diagnose the composition and energy distribution of the beam is developed. The ability of radio frequency quadrupole accelerators to simultaneously confine and accelerate the positive and negative ions of such a beam is demonstrated computationally and is confirmed experimentally, and a method to reestablish local charge neutrality in the beam after acceleration is conceived and simulated. The favorable scaling of such accelerators to small size and high frequency is illustrated. Finally, applications of the research to magnetic confinement fusion and topics for future study are presented.

  13. Combined reactor neutron beam and {sup 60}Co γ-ray radiation effects on CMOS APS image sensors

    SciTech Connect

    Wang, Zujun Chen, Wei; Sheng, Jiangkun; Liu, Yan; Xiao, Zhigang; Huang, Shaoyan; Liu, Minbo

    2015-02-15

    The combined reactor neutron beam and {sup 60}Co γ-ray radiation effects on complementary metal-oxide semiconductor (CMOS) active pixel sensors (APS) have been discussed and some new experimental phenomena are presented. The samples are manufactured in the standard 0.35-μm CMOS technology. Two samples were first exposed to {sup 60}Co γ-rays up to the total ionizing dose (TID) level of 200 krad(Si) at the dose rates of 50.0 and 0.2 rad(Si)/s, and then exposed to neutron fluence up to 1 × 10{sup 11} n/cm{sup 2} (1-MeV equivalent neutron fluence). One sample was first exposed to neutron fluence up to 1 × 10{sup 11} n/cm{sup 2} (1-MeV equivalent neutron fluence), and then exposed to {sup 60}Co γ-rays up to the TID level of 200 krad(Si) at the dose rate of 0.2 rad(Si)/s. The mean dark signal (K{sub D}), the dark signal non-uniformity (DSNU), and the noise (V{sub N}) versus the total dose and neutron fluence has been investigated. The degradation mechanisms of CMOS APS image sensors have been analyzed, especially for the interaction induced by neutron displacement damage and TID damage.

  14. 235U Determination using In-Beam Delayed Neutron Counting Technique at the NRU Reactor

    SciTech Connect

    Andrews, M. T.; Bentoumi, G.; Corcoran, E. C.; Dimayuga, I.; Kelly, D. G.; Li, L.; Sur, B.; Rogge, R. B.

    2015-11-17

    This paper describes a collaborative effort that saw the Royal Military College of Canada (RMC)’s delayed neutron and gamma counting apparatus transported to Canadian Nuclear Laboratories (CNL) for use in the neutron beamline at the National Research Universal (NRU) reactor. Samples containing mg quantities of fissile material were re-interrogated, and their delayed neutron emissions measured. This collaboration offers significant advantages to previous delayed neutron research at both CNL and RMC. This paper details the determination of 235U content in enriched uranium via the assay of in-beam delayed neutron magnitudes and temporal behavior. 235U mass was determined with an average absolute error of ± 2.7 %. This error is lower than that obtained at RMCC for the assay of 235U content in aqueous solutions (3.6 %) using delayed neutron counting. Delayed neutron counting has been demonstrated to be a rapid, accurate, and precise method for special nuclear material detection and identification.

  15. Neutron beam optimization based on a 7Li(p,n)7Be reaction for treatment of deep-seated brain tumors by BNCT

    NASA Astrophysics Data System (ADS)

    Zahra Ahmadi, Ganjeh; S. Farhad, Masoudi

    2014-10-01

    Neutron beam optimization for accelerator-based Boron Neutron Capture Therapy (BNCT) is investigated using a 7Li(p,n)7Be reaction. Design and optimization have been carried out for the target, cooling system, moderator, filter, reflector, and collimator to achieve a high flux of epithermal neutron and satisfy the IAEA criteria. Also, the performance of the designed beam in tissue is assessed by using a simulated Snyder head phantom. The results show that the optimization of the collimator and reflector is critical to finding the best neutron beam based on the 7Li(p,n)7Be reaction. Our designed beam has 2.49×109n/cm2s epithermal neutron flux and is suitable for BNCT of deep-seated brain tumors.

  16. Are high energy proton beams ideal for AB-BNCT? A brief discussion from the viewpoint of fast neutron contamination control.

    PubMed

    Lee, Pei-Yi; Liu, Yuan-Hao; Jiang, Shiang-Huei

    2014-06-01

    High energy proton beam (>8MeV) is favorable for producing neutrons with high yield. However, the produced neutrons are of high energies. These high energy neutrons can cause severe fast neutron contamination and degrade the BNCT treatment quality if they are not appropriately moderated. Hence, this study aims to briefly discuss the issue, from the viewpoint of fast neutron contamination control, whether high energy proton beam is ideal for AB-BNCT or not. In this study, D2O, PbF4, CaF2, and Fluental(™) were used standalone as moderator materials to slow down 1-, 6-, and 10-MeV parallelly incident neutrons. From the calculated results, we concluded that neutrons produced by high energy proton beam could not be easily moderated by a single moderator to an acceptable contamination level and still with reasonable epithermal neutron beam intensity. Hence, much more complicated and sophisticated designs of beam shaping assembly have to be developed when using high energy proton beams.

  17. 26Si excited states via one-neutron removal from a 27Si radioactive ion beam

    NASA Astrophysics Data System (ADS)

    Chen, J.; Chen, A. A.; Amthor, A. M.; Bazin, D.; Becerril, A. D.; Gade, A.; Galaviz, D.; Glasmacher, T.; Kahl, D.; Lorusso, G.; Matos, M.; Ouellet, C. V.; Pereira, J.; Schatz, H.; Smith, K.; Wales, B.; Weisshaar, D.; Zegers, R. G. T.

    2012-04-01

    A study of 26Si states by neutron removal from a fast radioactive beam of 27Si has been performed. A beam of 27Si of energy 84.3 MeV/nucleon impinged on a polypropylene foil (C3H6) of 180 mg/cm2 thickness. Deexcitation γ rays were detected with a highly segmented germanium detector array, in coincidence with the 26Si recoils, and the corresponding 26Si level energies were determined. In comparing our results to two previous γ-ray spectroscopic studies of 26Si level structures, we find good agreement with a recent measurement of the 12C(16O,2nγ)26Si reaction. Our results support the use of excitation energies from that study in helping determine the important resonance energies for the thermonuclear 25Al(p,γ)26Si reaction rate. We do not observe a bound state at 4093 keV reported in an earlier study of the 24Mg(3He,nγ)26Si reaction.

  18. High Intensity, Pulsed, D-D Neutron Generator

    SciTech Connect

    Williams, D. L.; Vainionpaa, J. H.; Jones, G.; Piestrup, M. A.; Gary, C. K.; Harris, J. L.; Fuller, M. J.; Cremer, J. T.; Ludewigt, Bernhard A.; Kwan, J. W.; Reijonen, J.; Leung, K.-N.; Gough, R. A.

    2008-08-01

    Single ion-beam RF-plasma neutron generators are presented as a laboratory source of intense neutrons. The continuous and pulsed operations of such a neutron generator using the deuterium-deuterium fusion reaction are reported. The neutron beam can be pulsed by switching the RF plasma and/or a gate electrode. These generators are actively vacuum pumped so that a continuous supply of deuterium gas is present for the production of ions and neutrons. This contributes to the generator's long life. These single-beam generators are capable of producing up to 1E10 n/s. Previously, Adelphi and LBNL have demonstrated these generators' applications in fast neutron radiography, Prompt Gamma Neutron Activation Analysis (PGNAA) and Neutron Activation Analysis (NAA). Together with an inexpensive compact moderator, these high-output neutron generators extend useful applications to home laboratory operations.

  19. Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device

    PubMed Central

    Randers-Pehrson, Gerhard; Marino, Stephen A.; Garty, Guy; Harken, Andrew; Brenner, David J.

    2015-01-01

    A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n)3He and D(d,n)3He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima. PMID:26273118

  20. NEUTRON ACTIVATION ANALYSIS APPLICATIONS AT THE SAVANNAH RIVER SITE USING AN ISOTOPIC NEUTRON SOURCE

    SciTech Connect

    Diprete, D; C Diprete, C; Raymond Sigg, R

    2006-08-14

    NAA using {sup 252}Cf is used to address important areas of applied interest at SRS. Sensitivity needs for many of the applications are not severe; analyses are accomplished using a 21 mg {sup 252}Cf NAA facility. Because NAA allows analysis of bulk samples, it offers strong advantages for samples in difficult-to-digest matrices when its sensitivity is sufficient. Following radiochemical separation with stable carrier addition, chemical yields for a number methods are determined by neutron activation of the stable carrier. In some of the cases where no suitable stable carriers exist, the source has been used to generate radioactive tracers to yield separations.

  1. Determination and validation of prompt k0-factors with a monochromatic neutron beam at the Dhruva reactor

    NASA Astrophysics Data System (ADS)

    Nair, A. G. C.; Acharya, R.; Sudarshan, K.; Tripathi, R.; Reddy, A. V. R.; Goswami, A.

    2006-08-01

    Prompt Gamma-ray Neutron Activation Analysis (PGNAA) was carried out using a reflected neutron beam of 0.018 eV energy at the Dhruva research reactor, Bhabha Atomic Research Centre, Mumbai, India. The neutron beam characteristics, such as dimension, homogeneity and thermal equivalent flux were evaluated. The prompt k0-factors of about 15 elements were determined versus the 1951.1 keV gamma-ray of the 35Cl(n,γ) reaction. These prompt k0-factors are compared with the recommended k0-values for thermal neutrons and were found to be in good agreement, except for Gd, Cd and Hg. The internal mono-standard method was applied to analyze a meteorite and a stainless steel alloy (SS 316 M) using the recommended k0-values from the literature. As to the alloy, the measured concentrations were in good agreement with the nominal composition. For the meteorite sample, the concentrations of the major elements were in good agreement with the values determined using conventional neutron activation analysis.

  2. Diamonds for beam instrumentation

    SciTech Connect

    Griesmayer, Erich

    2013-04-19

    Diamond is perhaps the most versatile, efficient and radiation tolerant material available for use in beam detectors with a correspondingly wide range of applications in beam instrumentation. Numerous practical applications have demonstrated and exploited the sensitivity of diamond to charged particles, photons and neutrons. In this paper, a brief description of a generic diamond detector is given and the interaction of the CVD diamond detector material with protons, electrons, photons and neutrons is presented. Latest results of the interaction of sCVD diamond with 14 MeV mono-energetic neutrons are shown.

  3. Active Interrogation of Sensitive Nuclear Material Using Laser Driven Neutron Beams

    SciTech Connect

    Favalli, Andrea; Roth, Markus

    2015-05-01

    An investigation of the viability of a laser-driven neutron source for active interrogation is reported. The need is for a fast, movable, operationally safe neutron source which is energy tunable and has high-intensity, directional neutron production. Reasons for the choice of neutrons and lasers are set forth. Results from the interrogation of an enriched U sample are shown.

  4. Neutron Generators Developed at LBNL for Homeland Security andImaging Applications

    SciTech Connect

    Reijonen, Jani

    2006-08-13

    The Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory has developed various types of advanced D-D (neutron energy 2.5 MeV), D-T (14 MeV) and T-T (0-9 MeV) neutron generators for wide range of applications. These applications include medical (Boron Neutron Capture Therapy), homeland security (Prompt Gamma Activation Analysis, Fast Neutron Activation Analysis and Pulsed Fast Neutron Transmission Spectroscopy) and planetary exploration with a sub-surface material characterization on Mars. These neutron generators utilize RF induction discharge to ionize the deuterium/tritium gas. This discharge method provides high plasma density for high output current, high atomic species from molecular gases, long life operation and versatility for various discharge chamber geometries. Four main neutron generator developments are discussed here: high neutron output co-axial neutron generator for BNCT applications, point neutron generator for security applications, compact and sub-compact axial neutron generator for elemental analysis applications. Current status of the neutron generator development with experimental data will be presented.

  5. Biomedical applications of ion-beam technology

    NASA Technical Reports Server (NTRS)

    Banks, B. A.; Weigand, A. J.; Gibbons, D. F.; Vankampen, C. L.; Babbush, C. A.

    1979-01-01

    Microscopically-rough surface texture of various biocompatible alloys and polymers produced by ion-beam sputtering may result in improvements in response of hard or soft tissue to various surgical implants.

  6. Production of neutron-rich Ca, Sn, and Xe isotopes in transfer-type reactions with radioactive beams

    SciTech Connect

    Adamian, G. G.; Antonenko, N. V.; Lacroix, D.

    2010-12-15

    The production cross sections of neutron-rich isotopes {sup 52,54,56,58,60}Ca, {sup 136,138,140,142}Sn, and {sup 146,148,150,152}Xe are predicted for future experiments in the diffusive multinucleon transfer reactions {sup 86,90,92,94}Kr, {sup 124,130,132,134}Sn, {sup 136,140,142,146}Xe, and {sup 138,144,146}Ba+{sup 48}Ca with stable and radioactive beams at incident energies close to the Coulomb barrier. Because of the small cross sections, the production of neutron-rich isotopes requires the optimal choice of projectile-target combinations and bombarding energies.

  7. Studies of the behavior of a reactor neutron beam at the sample position of a diffractometer using silicon monochromators

    NASA Astrophysics Data System (ADS)

    Ahmed, F. U.; Ahsan, M. H.; Khan, Aysha A.; Kamal, I.; Awal, M. A.; Ahmad, A. A. Z.

    1992-02-01

    A computer program TISTA has been developed for calculation of different aspects of designing a double axis neutron spectrometer at the TRIGA Mark II research reactor of the Atomic Energy Research Establishment, Dhaka, Bangladesh. The mathematical algorithms used in this program are based on the formalisms used by Fischer, Sabine and Bacon. Angle and energy resolutions and flux density as functions of neutron wave length, beam collimation, crystal asymmetry and deviation from zero-Bragg-angle position for different silicon crystal planes (111, 220, 311) have been calculated.

  8. Chromosomal aberrations in peripheral blood lymphocytes exposed to a mixed beam of low energy neutrons and gamma radiation.

    PubMed

    Wojcik, A; Obe, G; Lisowska, H; Czub, J; Nievaart, V; Moss, R; Huiskamp, R; Sauerwein, W

    2012-09-01

    Cells exposed to thermal neutrons are simultaneously damaged by radiations with high and low linear energy transfer (LET). A question relevant for the assessment of risk of exposure to a mixed beam is whether the biological effect of both radiation types is additive or synergistic. The aim of the present investigation was to calculate whether the high and low LET components of a thermal neutron field interact when damaging cells. Human peripheral blood lymphocytes were exposed to neutrons from the HB11 beam at the Institute for Energy and Transport, Petten, Netherlands, in a 37 °C water phantom at varying depths, where the mix of high and low LET beam components differs. Chromosomal aberrations were analysed and the relative biological effectiveness (RBE) values as well as the expected contributions of protons and photons to the aberration yield were calculated based on a dose response of aberrations in lymphocytes exposed to (60)Co gamma radiation. The RBE for 10 dicentrics per 100 cells was 3 for mixed beam and 7.2 for protons. For 20 dicentrics per 100 cells the respective values were 2.4 and 5.8. Within the limitations of the experimental setup the results indicate that for this endpoint there is no synergism between the high and low LET radiations.

  9. Comparison of Reported and Inferred Neutral Beam Performance by Neutron and Spectroscopic Measurements on DIII-D

    NASA Astrophysics Data System (ADS)

    Rozansky, R. N.; Grierson, B. A.; Heidbrink, W. W.

    2013-10-01

    The DIII-D tokamak is equipped with eight sources for neutral beam injection (NBI). Recent studies of neutron rates indicate that the power injected by each source can differ from the values derived from NBI transmission calculations. During experimental operation, the first discharge of each day is a ``reference shot'' that provides information on wall conditions and neutral beam performance. During this reference shot all NBI sources are injected into steady plasma conditions enabling qualitative comparison between sources, and absolute comparison with fusion neutron counters. Spectroscopic diagnostics measure the neutral beam emission from up to six of the eight sources, as well as the circulating fast-ion content injected from all sources by the fast-ion D-alpha (FIDA) technique. Comparison of the neutron rate, beam emission, and fast-ion emission will be made with theoretical models of these processes in order to determine qualitative and quantitative agreement with expectations derived from reported NBI powers. Work supported by the National Undergraduate Fellowship Program in Plasma Physics and Fusion Energy Sciences and the US Department of Energy under DE-FC02-04ER54698, DE-AC02-09CH11466, and SC-G903402.

  10. Development and Applications of Time of Flight Neutron Depth Profiling

    SciTech Connect

    Bingham Cady; Kenan Unlu

    2005-03-17

    The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. For example, the subtle differences in spatial distribution and composition of many chemical species in the near surface region and across interfacial boundaries can significantly alter the electronic and optical properties of materials. A number of analytical techniques for depth profiling have been developed during the last two decades. neutron Depth Profiling (NDP) is one of the leading analytical techniques. The NDP is a nondestructive near surface technique that utilizes thermal/cold neutron beam to measure the concentration of specific light elements versus their depth in materials. The depth is obtained from the energy loss of protons, alphas or recoil atoms in substrate materials. Since the charged particle energy determination using surface barrier detector is used for NDP, the depth resolution is highly dependent on the detectors an d detection instruments. The depth resolutions of a few tens of nm are achieved with available NDP facilities in the world. However, the performance of NDP needs to be improved in order to obtain a few A depth resolutions.

  11. Dy-IP characterization and its application for experimental neutron radiography tests under realistic conditions

    NASA Astrophysics Data System (ADS)

    Tamaki, Masayoshi; Iida, Kazuhiro; Mori, Noriaki; Lehmann, Eberhard H.; Vontobel, Peter; Estermann, Mirko

    2005-04-01

    Imaging plates containing Dy for neutron radiography have been designed, fabricated and tested experimentally. Using the imaging plates combined with the developed NR system and the honeycomb collimator, quantitative neutron radiograph, which is free from scattered neutron and γ-ray, has been obtained. Application has been conducted for the post-irradiation examination for the nuclear fuel pin.

  12. Application of the pencil-beam redefinition algorithm in heterogeneous media for proton beam therapy

    NASA Astrophysics Data System (ADS)

    Egashira, Y.; Nishio, T.; Hotta, K.; Kohno, R.; Uesaka, M.

    2013-02-01

    In proton beam therapy, changes in the proton range due to lateral heterogeneity may cause serious errors in the dose distribution. In the present study, the pencil-beam redefinition algorithm (PBRA) was applied to proton beam therapy to address the problem of lateral density heterogeneity. In the calculation, the phase-space parameters were characterized for multiple range (i.e. proton energy) bins for given pencil beams. The particles that were included in each pencil beam were transported and redefined periodically until they had stopped. The redefined beams formed a detouring path that was different from that of the non-redefined pencil beams, and the path of each redefined beam was straight. The results calculated by the PBRA were compared with measured proton dose distributions in a heterogeneous slab phantom and an anthropomorphic phantom. Through the beam redefinition process, the PBRA was able to predict the measured proton-detouring effects. Therefore, the PBRA may allow improved calculation accuracy when dealing with lateral heterogeneities in proton therapy applications.

  13. Application of reactor-pumped lasers to power beaming

    SciTech Connect

    Repetti, T.E.

    1991-10-01

    Power beaming is the concept of centralized power generation and distribution to remote users via energy beams such as microwaves or laser beams. The power beaming community is presently performing technical evaluations of available lasers as part of the design process for developing terrestrial and space-based power beaming systems. This report describes the suitability of employing a nuclear reactor-pumped laser in a power beaming system. Although there are several technical issues to be resolved, the power beaming community currently believes that the AlGaAs solid-state laser is the primary candidate for power beaming because that laser meets the many design criteria for such a system and integrates well with the GaAs photodiode receiver array. After reviewing the history and physics of reactor-pumped lasers, the advantages of these lasers for power beaming are discussed, along with several technical issues which are currently facing reactor-pumped laser research. The overriding conclusion is that reactor-pumped laser technology is not presently developed to the point of being technially or economically competitive with more mature solid-state technologies for application to power beaming. 58 refs.

  14. A new e-beam application in the pharmaceutical industry

    NASA Astrophysics Data System (ADS)

    Sadat, Theo; Malcolm, Fiona

    2005-10-01

    The paper presents a new electron beam application in the pharmaceutical industry: an in-line self-shielded atropic transfer system using electron beam for surface decontamination of products entering a pharmaceutical filling line. The unit was developed by Linac Technologies in response to the specifications of a multi-national pharmaceutical company, to solve the risk of microbial contamination entering a filling line housed inside an isolator. In order to fit the sterilization unit inside the pharmaceutical plant, a "miniature" low-energy (200 keV) electron beam accelerator and e-beam tunnel were designed, all conforming to the pharmaceutical good manufacturing practice (GMP) regulations. Process validation using biological indicators is described, with reference to the regulations governing the pharmaceutical industry. Other industrial applications of a small-sized self-shielded electron beam sterilization unit are mentioned.

  15. Plutonium Measurements with a Fast-Neutron Multiplicity Counter for Nuclear Safeguards Applications

    SciTech Connect

    Jennifer L. Dolan; Marek Flaska; Alexis Poitrasson-Riviere; Andreas Enqvist; Paolo Peerani; David L. Chichester; Sara A. Pozzi

    2014-11-01

    Measurements were performed at the Joint Research Centre in Ispra, Italy to field test a fast-neutron multiplicity counter developed at the University of Michigan. The measurements allowed the illustration of the system’s photon discrimination abilities, efficiency when measuring neutron multiplicity, ability to characterize 240Pueff mass, and performance relative to a currently deployed neutron coincidence counter. This work is motivated by the need to replace and improve upon 3He neutron detection systems for nuclear safeguards applications.

  16. Testing The High-Energy Prompt Neutron Signature At Low Beam Energies

    SciTech Connect

    Thompson, Scott J.; Kinlaw, Mathew T.; Hunt, Alan W.

    2011-06-01

    Prompt fission neutrons continue to be examined as a signature for detecting the presence of fissionable material. This technique exploits the neutron energy limitations inherent with photonuclear emissions from non-fissionable material, allowing prompt fission neutrons to be identified and engaged for detecting nuclear material. Prompt neutron signal measurements were acquired with bremsstrahlung endpoint energies of 6 MeV for 18 targets comprised of both fissionable and non-fissionable material; delayed neutron measurements were also collected as a reference. The {sup 238}U target was also shielded with increasing thicknesses of lead or borated polyethylene to compare the resulting detection rates of the prompt and delayed fission neutron signals.

  17. Mechanical approach to the neutrons spectra collimation and detection

    SciTech Connect

    Sadeghi, H.; Roshan, M. V.

    2014-11-15

    Neutrons spectra from most of known sources require being collimated for numerous applications; among them one is the Neutron Activation Analysis. High energy neutrons are collimated through a mechanical procedure as one of the most promising methods. The output energy of the neutron beam depends on the velocity of the rotating Polyethylene disks. The collimated neutrons are then measured by an innovative detection technique with high accuracy.

  18. Mechanical approach to the neutrons spectra collimation and detection.

    PubMed

    Sadeghi, H; Roshan, M V

    2014-11-01

    Neutrons spectra from most of known sources require being collimated for numerous applications; among them one is the Neutron Activation Analysis. High energy neutrons are collimated through a mechanical procedure as one of the most promising methods. The output energy of the neutron beam depends on the velocity of the rotating Polyethylene disks. The collimated neutrons are then measured by an innovative detection technique with high accuracy.

  19. A study of the concept of a fission-plate converter as a source for an epithermal neutron beam

    SciTech Connect

    1994-12-31

    It has been suggested that a Fission-Plate Converter (FPC) at a reactor can enhance the intense of an epithermal neutron beam produced by the reactor. By computer modeling, this concept has been applied to two sets of reactors to study how effective a FPC might be. The first set of reactors contains high-powered research reactors and is represented by the Missouri University Research Reactor and the Georgia Institute of Technology Research Reactor. The second set combines the FPC into the core of a low-powered reactor, yielding a thin, large area, reactor that we call a slab reactor. For these reactors, epithermal fluxes above 1 x 10{sup 9} n/cm{sup 2}{center_dot}sec are predicted while the fast-neutron doses per epithermal neutron are < 3 x 10{sup -11} cGy{center_dot}cm{sup 2}/n.

  20. Pyroelectric and ferroelectric semiconductors: dynamic holographic grating recording, generation of self-focused electron beam, X-rays, and neutrons

    NASA Astrophysics Data System (ADS)

    Kukhtarev, N. V.; Kukhtareva, T. V.; Land, P.; Wang, J. C.

    2007-09-01

    Optical and electrical effects in semiconductors and ferroelectric crystals will be modeled. Standard photorefractive equations are supplemented by the equation of state for the polarization density following Devonshire-Ginsburg-Landau (DGL) approach. We have derived equations for pyroelectric and photogalvanic contribution to the holographic grating recording in ferroelectric materials. We will consider double-functional holographic interferometer, based on holographic pyroelectric current and optical beam coupling. Crystal electrostatic accelerators, based on charging of ferroelectric crystals by pyroelectric and photogalvanic effects are discussed in relation to generation of self-focused electron beam, X-rays and neutrons.

  1. Micromachining of commodity plastics by proton beam writing and fabrication of spatial resolution test-chart for neutron radiography

    NASA Astrophysics Data System (ADS)

    Sakai, T.; Yasuda, R.; Iikura, H.; Nojima, T.; Matsubayashi, M.; Kada, W.; Kohka, M.; Satoh, T.; Ohkubo, T.; Ishii, Y.; Takano, K.

    2013-07-01

    Proton beam writing is a direct-write technique and a promising method for the micromachining of commodity plastics such as acrylic resins. Herein, we describe the fabrication of microscopic devices made from a relatively thick (∼75 μm) acrylic sheet using proton beam writing. In addition, a software package that converts image pixels into coordinates data was developed, and the successful fabrication of a very fine jigsaw puzzle was achieved. The size of the jigsaw puzzle pieces was 50 × 50 μm. For practical use, a prototype of a line and space test-chart was also successfully fabricated for the determination of spatial resolution in neutron radiography.

  2. Large animal normal tissue tolerance using an epithermal neutron beam and borocaptate sodium.

    PubMed

    Gavin, P R; Huiskamp, R; Wheeler, F J; Kraft, S L; DeHaan, C E

    1993-01-01

    Irradiation of the canine head following intravenous Na2B12H11SH (BSH) administration has provided useful information concerning the tolerance of skin and brain to the resultant complex form of irradiation. The effect of the boron capture reaction in skin and brain has provided estimates of the influence of the microscopic dosimetry involved. Dogs irradiated with the epithermal beam alone provided valuable insight into the relative biological effectiveness (RBE) of the fast neutron component (> 10 keV) of the epithermal beam. When compared with literature values for X-rays for the occurrence of skin necrosis in dogs, an RBE of 4.5 was derived. Previous pharmacokinetic data concerning the distribution of Na2B12H11SH (BSH) to blood and brain has been used to obtain input parameters for computer models of the microvasculature of the brain. Monte Carlo computer models were used to simulate the microscopic distribution of BSH in the normal brain. The term compound factor describes the product of the microscopic boron fission fragment dose hitting the nucleus and the relative biologic effectiveness divided by the macroscopic equilibrium dose of the boron reaction in the tissue of interest. The computed compound factor for Na2B12H11SH (BSH) in normal brain was 0.37. This factor agreed very well with the value of 0.32 obtained for the brain necrosis with the dog irradiations. The compound factor for the dog's skin was experimentally derived from the dog experiments and was equal to 0.5.

  3. Probing Shell Structure and Shape Changes in Neutron-Rich Sulfur Isotopes through Transient-Field g-Factor Measurements on Fast Radioactive Beams of {sup 38}S and {sup 40}S

    SciTech Connect

    Davies, A.D.; Becerril, A.; Brown, B.A.; Campbell, C.M.; Cook, J.M.; Dinca, D.C.; Terry, J.R.; Zwahlen, H.; Stuchbery, A.E.; Davidson, P.M.; Mantica, P.F.; Liddick, S.N.; Tomlin, B.E.; Wilson, A.N.; Gade, A.; Mertzimekis, T.J.; Mueller, W.F.; Yoneda, K.

    2006-03-24

    The shell structure underlying shape changes in neutron-rich nuclei near N=28 has been investigated by a novel application of the transient-field technique to measure the first-excited-state g factors in {sup 38}S and {sup 40}S produced as fast radioactive beams. There is a fine balance between proton and neutron contributions to the magnetic moments in both nuclei. The g factor of deformed {sup 40}S does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.

  4. Green Zia Application Sandia National Laboratories' Neutron Generator Production Facility

    SciTech Connect

    SAAD, MAX P.; RICHARDSON, ANASTASIA DAWN

    2003-03-01

    The Green Zia Environmental Excellence Program is a voluntary program designed to support and assist all New Mexico businesses to achieve environmental excellence through continuous improvement and effective energy management. The program encourages integration of environmental excellence into business operations and management practices through the establishment of a prevention-based environmental management system. The Neutron Generator Production Facility has participated in the Green Zia Environmental Excellence Program for two years. This document is the submittal application for inclusion in the 2003 Green Zia program year.

  5. Boron self-shielding effects on dose delivery of neutron capture therapy using epithermal beam and boronophenylalanine.

    PubMed

    Ye, S J

    1999-11-01

    Previous dosimetry studies for boron neutron capture therapy have often neglected the thermal neutron self-shielding effects caused by the 10B accumulation in the brain and the tumor. The neglect of thermal neutron flux depression, therefore, results in an overestimation of the actual dose delivery. The relevant errors are expected to be more pronounced when boronophenylalanine is used in conjunction with an epithermal neutron beam. In this paper, the boron self-shielding effects are calculated in terms of the thermal neutron flux depression across the brain and the dose delivered to the tumors. The degree of boron self-shielding is indicated by the difference between the thermal neutron fluxes calculated with and without considering a 10B concentration as part of the head phantom composition. The boron self-shielding effect is found to increase with increasing 10B concentrations and penetration depths from the skin. The calculated differences for 10B concentrations of 7.5-30 ppm are 2.3%-8.3% at 2.3 cm depth (depth of the maximum brain dose) and 4.6%-17% at 7.3 cm depth (the center of the brain). The additional self-shielding effects by the 10B concentration in a bulky tumor are investigated for a 3-cm-diam spherical tumor located either near the surface (3.3 cm depth) or at the center of the brain (7.3 cm depth) along the beam centerline. For 45 ppm of 10B in the tumor and 15 ppm of 10B in the brain, the dose delivered to the tumors is approximately 10% lower at 3.3 cm depth and 20% lower at the center of the brain, compared to the dose neglecting the boron self-shielding in transport calculations.

  6. Gamma beam industrial applications at ELI-NP

    NASA Astrophysics Data System (ADS)

    Suliman, Gabriel; Iancu, Violeta; Ur, Calin A.; Iovea, Mihai; Daito, Izuru; Ohgaki, Hideaki

    2016-09-01

    The Nuclear Physics oriented pillar of the pan-European Extreme Light Infrastructure (ELI-NP) will host an ultra-bright, energy tunable, and quasi-monochromatic gamma-ray beam system in the range of 0.2-19.5 MeV produced by laser Compton backscattering. This gamma beam satisfies the criteria for large-size product investigations with added capabilities like isotope detection through the use of nuclear resonance fluorescence (NRF) and is ideal for non-destructive testing applications. Two major applications of gamma beams are being envisaged at ELI-NP: industrial applications based on NRF and industrial radiography and tomography. Both applications exploit the unique characteristics of the gamma beam to deliver new opportunities for the industry. Here, we present the experimental setups proposed at ELI-NP and discuss their performance based on analytical calculations and GEANT4 numerical simulations. One of the main advantages of using the gamma beam at ELI-NP for applications based on NRF is the availability of an advanced detector array, which can enhance the advantages already provided by the high quality of the gamma beam.

  7. Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground

    SciTech Connect

    Powell, J.R.; Botts, T.E.; Hertzberg, A.

    1981-01-01

    Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.

  8. Application of the pencil-beam redefinition algorithm in heterogeneous media for proton beam therapy.

    PubMed

    Egashira, Y; Nishio, T; Hotta, K; Kohno, R; Uesaka, M

    2013-02-21

    In proton beam therapy, changes in the proton range due to lateral heterogeneity may cause serious errors in the dose distribution. In the present study, the pencilbeam redefinition algorithm (PBRA) was applied to proton beam therapy to address the problem of lateral density heterogeneity. In the calculation, the phase-space parameters were characterized for multiple range (i.e. proton energy) bins for given pencil beams. The particles that were included in each pencil beam were transported and redefined periodically until they had stopped. The redefined beams formed a detouring path that was different from that of the non-redefined pencil beams, and the path of each redefined beam was straight. The results calculated by the PBRA were compared with measured proton dose distributions in a heterogeneous slab phantom and an anthropomorphic phantom. Through the beam redefinition process, the PBRA was able to predict the measured proton-detouring effects. Therefore, the PBRA may allow improved calculation accuracy when dealing with lateral heterogeneities in proton therapy applications.

  9. Characterization of an explosively bonded aluminum proton beam window for the Spallation Neutron Source

    SciTech Connect

    McClintock, David A; Janney, Jim G; Parish, Chad M

    2014-01-01

    An effort is underway at the Spallation Neutron Source (SNS) to change the design of the 1st Generation high-nickel alloy proton beam window (PBW) to one that utilizes aluminum for the window material. One of the key challenges to implementation of an aluminum PBW at the SNS was selection of an appropriate joining method to bond an aluminum window to the stainless steel bulk shielding of the PBW assembly. An explosively formed bond was selected as the most promising joining method for the aluminum PBW design. A testing campaign was conducted to evaluate the strength and efficacy of explosively formed bonds that were produced using two different interlayer materials: niobium and titanium. The characterization methods reported here include tensile testing, thermal-shock leak testing, optical microscopy, and advanced scanning electron microscopy. All tensile specimens examined failed in the aluminum interlayer and measured tensile strengths were all slightly greater than the native properties of the aluminum interlayer, while elongation values were all slightly lower. A leak developed in the test vessel with a niobium interlayer joint after repeated thermal-shock cycles, and was attributed to an extensive crack network that formed in a layer of niobium-rich intermetallics located on the bond interfaces of the niobium interlayer; the test vessel with a titanium interlayer did not develop a leak under the conditions tested. Due to the experience gained from these characterizations, the explosively formed bond with a titanium interlayer was selected for the aluminum PBW design at the SNS.

  10. Targets and Secondary Beam Extraction

    NASA Astrophysics Data System (ADS)

    Noah, Etam

    2014-02-01

    Several applications make use of secondary beams of particles generated by the interaction of a primary beam of particles with a target. Spallation neutrons, bremsstrahlung photon-produced neutrons, radioactive ions and neutrinos are available to users at state-of-the-art facilities worldwide. Plans for even higher secondary beam intensities place severe constraints on the design of targets. This article reports on the main targetry challenges and highlights a variety of solutions for targetry and secondary beam extraction. Issues related to target station layout, instrumentation at the beam-target interface, safety and radioprotection are also discussed.

  11. Neutron reflectometry on highly absorbing films and its application to 10B4C-based neutron detectors

    PubMed Central

    Piscitelli, F.; Khaplanov, A.; Devishvili, A.; Schmidt, S.; Höglund, C.; Birch, J.; Dennison, A. J. C.; Gutfreund, P.; Hall-Wilton, R.; Van Esch, P.

    2016-01-01

    Neutron reflectometry is a powerful tool used for studies of surfaces and interfaces. The absorption in the typical studied materials is neglected and this technique is limited only to the reflectivity measurement. For strongly absorbing nuclei, the absorption can be directly measured by using the neutron-induced fluorescence technique which exploits the prompt particle emission of absorbing isotopes. This technique is emerging from soft matter and biology where highly absorbing nuclei, in very small quantities, are used as a label for buried layers. Nowadays, the importance of absorbing layers is rapidly increasing, partially because of their application in neutron detection; a field that has become more active also due to the 3He-shortage. We extend the neutron-induced fluorescence technique to the study of layers of highly absorbing materials, in particular 10B4C. The theory of neutron reflectometry is a commonly studied topic; however, when a strong absorption is present the subtle relationship between the reflection and the absorption of neutrons is not widely known. The theory for a general stack of absorbing layers has been developed and compared to measurements. We also report on the requirements that a 10B4C layer must fulfil in order to be employed as a converter in neutron detection. PMID:26997902

  12. Epithermal neutron instrumentation at ISIS

    NASA Astrophysics Data System (ADS)

    Gorini, G.; Festa, G.; Andreani, C.

    2014-12-01

    The advent of pulsed neutron sources makes available high epithermal neutron fluxes (in the energy range between 500 meV and 100 eV). New dedicated instrumentation, such as Resonance Detectors, was developed at ISIS spallation neutron source in the last years to apply the specific properties of this kind of neutron beam to the study of condensed matter. New detection strategies like Filter Difference method and Foil Cycling Technique were also developed in parallel to the detector improvement at the VESUVIO beamline. Recently, epithermal neutron beams were also used at the INES beamline to study elemental and isotopic composition of materials, with special application to cultural heritage studies. In this paper we review a series of epithermal neutron instrumentation developed at ISIS, their evolution over time and main results obtained.

  13. Associated-particle sealed-tube neutron generators and hodoscopes for NDA applications

    NASA Astrophysics Data System (ADS)

    Rhodes, E.; Peters, C. W.

    With radioisotope sources, gamma-ray transmission hodoscopes can inspect canisters and railcars to monitor rocket motors, detect nuclear warheads by their characteristic strong gamma-ray absorption, or count nuclear warheads inside a missile by low-resolution tomography. Intrinsic gamma-ray radiation from warheads can also be detected in a passive mode. Neutron hodoscopes can use neutron transmission, intrinsic neutron emission, or reactions stimulated by a neutron source, in treaty verification roles. Gamma-ray and neutron hodoscopes can be combined with a recently developed neutron diagnostic probe system, based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons, and that uses flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material.

  14. Associated-particle sealed-tube neutron generators and hodoscopes for NDA applications

    SciTech Connect

    Rhodes, E.; Peters, C.W.

    1991-12-01

    With radioisotope sources, gamma-ray transmission hodoscopes can inspect canisters and railcars to monitor rocket motors, can detect nuclear warheads by their characteristic strong gamma-ray absorption, or can count nuclear warheads inside a missile by low-resolution tomography. Intrinsic gamma-ray radiation from warheads can also be detected in a passive mode. Neutron hodoscopes can use neutron transmission, intrinsic neutron emission, or reactions stimulated by a neutron source, in treaty verification roles. Gamma-ray and neutron hodoscopes can be combined with a recently developed neutron diagnostic probe system, based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons, and that uses flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. 5 refs., 12 figs.

  15. Associated-particle sealed-tube neutron generators and hodoscopes for NDA applications

    SciTech Connect

    Rhodes, E. ); Peters, C.W. . Advanced Systems Div.)

    1991-01-01

    With radioisotope sources, gamma-ray transmission hodoscopes can inspect canisters and railcars to monitor rocket motors, can detect nuclear warheads by their characteristic strong gamma-ray absorption, or can count nuclear warheads inside a missile by low-resolution tomography. Intrinsic gamma-ray radiation from warheads can also be detected in a passive mode. Neutron hodoscopes can use neutron transmission, intrinsic neutron emission, or reactions stimulated by a neutron source, in treaty verification roles. Gamma-ray and neutron hodoscopes can be combined with a recently developed neutron diagnostic probe system, based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons, and that uses flight-time to electronically collimate transmitted neutrons and to tomographically image nuclides identified by reaction gamma-rays. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. 5 refs., 12 figs.

  16. Beamed microwave power transmission and its application to space

    NASA Technical Reports Server (NTRS)

    Brown, William C.; Eves, E. E.

    1992-01-01

    The general principles and special components of beamed microwave power transmission systems are outlined and their application to the space program are discussed. The beamed system is defined as starting with a dc source of power at the transmitting end, converting it to a microwave beam for transmission through space, and ending with the dc power output at the receiving end. An experimentally measured and certified dc-to-dc efficiency of 54 percent has been achieved, using this definition. The application discussed is that of a LEO to GEO transportation system that depends upon vehicles propelled by electric thrusters whose power is supplied by a microwave beam originating at the earth's surface. The advantages of the all-electronic system over a chemically propelled system are enumerated. The principles of space propulsion, particularly as they relate to electric propulsion, are outlined. Key components of the system and environmental considerations are discussed.

  17. Dual ion beam processed diamondlike films for industrial applications

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Kussmaul, M. T.; Banks, B. A.; Sovey, J. S.

    1991-01-01

    Single and dual beam ion source systems are used to generate amorphous diamondlike carbon (DLC) films, which were evaluated for a variety of applications including protective coatings on transmitting materials, power electronics as insulated gates and corrosion resistant barriers. A list of the desirable properties of DLC films along with potential applications are presented.

  18. Alternative materials to cadmium for neutron absorbers in safeguards applications

    SciTech Connect

    Freeman, Corey R; Geist, William H; West, James D

    2009-01-01

    Cadmium is increasingly difficult to use in safeguards applications because of rising cost and increased safety regulations. This work examines the properties of two materials produced by Ceradyne, inc. that present alternatives to cadmium for neutron shielding. The first is an aluminum metal doped with boron and the second is a boron carbide powder, compressed into a ceramic. Both are enriched in the {sup 10}B isotope. Two sheets of boron doped aluminum (1.1 mm and 5.2mm thick) and one sheet of boron carbide (8.5mm thick) were provided by Ceradyne for testing. An experiment was designed to test the neutron absorption capabilities of these three sheets against two different thicknesses of cadmium (0.6mm and 1.6mm thick). The thinner piece of aluminum boron alloy (1.1mm) performed as well as the cadmium pieces at absorbing neutrons. The thicker aluminum-boron plate provided more shielding than the cadmium sheets and the boron carbide performed best by a relatively large margin. Monte Carlo N-Particle eXtended (MCNPX) transport code modeling of the experiment was performed to provide validaLed computational tools for predicting the behavior of systems in which these materials may be incorporated as alternatives to cadmium. MCNPX calculations predict that approximately 0.17mm of the boron carbide is equivalent to 0.6mm of cadmium. There are drawbacks to these materials that need to be noted when considering using them as replacements for cadmium. Notably, they may need to be thicker than cadmium, and are not malleable, requiring machining to fit any curved forms.

  19. Thermal and resonance neutrons generated by various electron and X-ray therapeutic beams from medical linacs installed in polish oncological centers

    PubMed Central

    Konefał, Adam; Orlef, Andrzej; Łaciak, Marcin; Ciba, Aleksander; Szewczuk, Marek

    2012-01-01

    Background High-energy photon and electron therapeutic beams generated in medical linear accelerators can cause the electronuclear and photonuclear reactions in which neutrons with a broad energy spectrum are produced. A low-energy component of this neutron radiation induces simple capture reactions from which various radioisotopes originate and in which the radioactivity of a linac head and various objects in the treatment room appear. Aim The aim of this paper is to present the results of the thermal/resonance neutron fluence measurements during therapeutic beam emission and exemplary spectra of gamma radiation emitted by medical linac components activated in neutron reactions for four X-ray beams and for four electron beams generated by various manufacturers’ accelerators installed in typical concrete bunkers in Polish oncological centers. Materials and methods The measurements of neutron fluence were performed with the use of the induced activity method, whereas the spectra of gamma radiation from decays of the resulting radioisotopes were measured by means of a portable high-purity germanium detector set for field spectroscopy. Results The fluence of thermal neutrons as well as resonance neutrons connected with the emission of a 20 MV X-ray beam is ∼106 neutrons/cm2 per 1 Gy of a dose in water at a reference depth. It is about one order of magnitude greater than that for the 15 MV X-ray beams and about two orders of magnitude greater than for the 18–22 MeV electron beams regardless of the type of an accelerator. Conclusion The thermal as well as resonance neutron fluence depends strongly on the type and the nominal potential of a therapeutic beam. It is greater for X-ray beams than for electrons. The accelerator accessories and other large objects should not be stored in a treatment room during high-energy therapeutic beam emission to avoid their activation caused by thermal and resonance neutrons. Half-lives of the radioisotopes originating from

  20. Neutron Energy and Time-of-flight Spectra Behind the Lateral Shield of a High Energy Electron Accelerator Beam Dump,Part I: Measurements

    SciTech Connect

    Roesler, Stefan

    2002-09-24

    Neutron energy and time-of-flight spectra were measured behind the lateral shield of the electron beam dump at the Final Focus Test Beam (FFTB) facility at the Stanford Linear Accelerator Center. The neutrons were produced by a 28.7 GeV electron beam hitting the aluminum beam dump of the FFTB which is housed inside a thick steel and concrete shield. The measurements were performed using a NE213 organic liquid scintillator behind different thicknesses of the concrete shield of 274 cm, 335 cm, and 396 cm, respectively. The neutron energy spectra between 6 and 800 MeV were obtained by unfolding the measured pulse height spectrum with the detector response function. The attenuation length of neutrons in concrete was then derived. The spectra of neutron time-of-flight between beam on dump and neutron detection by NE213 were also measured. The corresponding experimental results were simulated with the FLUKA Monte Carlo code. The experimental results show good agreement with the simulated results.

  1. Neutron energy and time-of-flight spectra behind the lateral shield of a high energy electron accelerator beam dump. Part I: measurements

    NASA Astrophysics Data System (ADS)

    Taniguchi, S.; Nakamura, T.; Nunomiya, T.; Iwase, H.; Yonai, S.; Sasaki, M.; Rokni, S. H.; Liu, J. C.; Kase, K. R.; Roesler, S.

    2003-05-01

    Neutron energy and time-of-flight spectra were measured behind the lateral shield of the electron beam dump at the Final Focus Test Beam (FFTB) facility at the Stanford Linear Accelerator Center. The neutrons were produced by a 28.7 GeV electron beam hitting the aluminum beam dump of the FFTB which is housed inside a thick steel and concrete shield. The measurements were performed using an NE213 organic liquid scintillator behind different thicknesses of the concrete shield of 274, 335, and 396 cm, respectively. The neutron energy spectra between 6 and 800 MeV were obtained by unfolding the measured pulse height spectrum with the detector response function. The attenuation length of neutrons in concrete was then derived. The spectra of neutron time-of-flight between beam on dump and neutron detection by NE213 were also measured. The corresponding experimental results were simulated with the FLUKA Monte Carlo code. The experimental results show good agreement with the simulated results.

  2. Neutron Energy and Time-of-flight Spectra Behind the Lateral Shield of a High Energy Electron Accelerator Beam Dump, Part II: Monte Carlo Simulations

    SciTech Connect

    Roesler, Stefan

    2002-09-19

    Energy spectra of high-energy neutrons and neutron time-of-flight spectra were calculated for the setup of experiment T-454 performed with a NE213 liquid scintillator at the Final Focus Test Beam (FFTB) facility at the Stanford Linear Accelerator Center. The neutrons were created by the interaction a 28.7 GeV electron beam in the aluminum beam dump of the FFTB which is housed inside a thick steel and concrete shielding. In order to determine the attenuation length of high-energy neutrons additional concrete shielding of various thicknesses was placed outside the existing shielding. The calculations were performed using the FLUKA interaction and transport code. The energy and time-of-flight were recorded for the location of the detector allowing a detailed comparison with the experimental data. A generally good description of the data is achieved adding confidence to the use of FLUKA for the design of shielding for high-energy electron accelerators.

  3. Experimental verification of a method to create a variable energy neutron beam from a monoenergetic, isotropic source using neutron elastic scatter and time of flight

    NASA Astrophysics Data System (ADS)

    Whetstone, Zachary D.; Flaska, Marek; Kearfott, Kimberlee J.

    2016-08-01

    An experiment was performed to determine the neutron energy of near-monoergetic deuterium-deuterium (D-D) neutrons that elastically scatter in a hydrogenous target. The experiment used two liquid scintillators to perform time of flight (TOF) measurements to determine neutron energy, with the start detector also serving as the scatter target. The stop detector was placed 1.0 m away and at scatter angles of π/6, π/4, and π/3 rad, and 1.5 m at a scatter angle of π/4 rad. When discrete 1 ns increments were implemented, the TOF peaks had estimated errors between -21.2 and 3.6% relative to their expected locations. Full widths at half-maximum (FWHM) ranged between 9.6 and 20.9 ns, or approximately 0.56-0.66 MeV. Monte Carlo simulations were also conducted that approximated the experimental setup and had both D-D and deuterium-tritium (DT) neutrons. The simulated results had errors between -17.2 and 0.0% relative to their expected TOF peaks when 1 ns increments were applied. The largest D-D and D-T FWHMs were 26.7 and 13.7 ns, or approximately 0.85 and 4.98 MeV, respectively. These values, however, can be reduced through manipulation of the dimensions of the system components. The results encourage further study of the neutron elastic scatter TOF system with particular interest in application to active neutron interrogation to search for conventional explosives.

  4. Development of high-intensity D-D and D-T neutron sources and neutron filters for medical and industrial applications

    SciTech Connect

    Verbeke, J.M.

    2000-05-10

    This thesis consists of three main parts. The first one relates to boron neutron capture therapy. It summarizes the guidelines obtained by numerical simulations for the treatment of shallow and deep-seated brain tumors, as well as the results on the design of beam-shaping assemblies to moderate D-D and D-T neutrons to epithermal energies. The second part is about boron neutron capture synovectomy for the treatment of rheumatoid arthritis. Optimal neutron energy for treatment and beam-shaping assembly designs are summarized in this section. The last part is on the development of the sealed neutron generator, including experimental results on the prototype ion source and the prototype accelerator column.

  5. Transport analysis of measured neutron energy spectra in a graphite stack with a collimated deuterium-tritium neutron beam

    SciTech Connect

    Tsechanski, A.; Ofek, R.; Goldfeld, A.; Shani, G.

    1989-02-01

    The Ben-Gurion University measurements of neutron energy spectra in a graphite stack, resulting from the scattering of 14.7-MeV neutrons streaming through a 6-cm-diam collimator in a 121-cm-thick paraffin wall, have been used as a benchmark for the compatability and accuracy of discrete ordinates, P/sub n/, and transport calculations and as a tool for fusion reactor neutronics. The transport analysis has been carried out with the DOT 4.2 discrete ordinates code and with cross sections processed with the NJOY code. Most of the parameters affecting the accuracy of the flux and L system scattering cross sections in the P/sub n/ approximation, the quadrature set employed, and the energy multigroup structure. First, a spectrum calculated with DOT 4.2, with a detector located on the axis of the system, was compared with a spectrum calculated with the MCNP Monte Carlo code, which was a preliminary verification of the DOT 4.2 results. Both calculated spectra were in good agreement. Next, the DOT 4.2 calculations were compared with the measured spectra. The comparison showed that the discrepancies between the measurements and the calculations increase as the distance between the detector and the system axis increases. This trend indicates that when the flux is determined mainly by multiple scatterings, a more divided multigroup structure should be employed.

  6. Wide Range Neutron Flux Measuring Channel for Aerospace Application

    SciTech Connect

    Cibils, R. M.; Busto, A.; Gonella, J. L.; Martinez, R.; Chielens, A. J.; Otero, J. M.; Nunez, M.; Tropea, S. E.

    2008-01-21

    The use of classical techniques for neutron flux measurements in nuclear reactors involves the switching between several detection chains as the power grows up to 10 decades. In space applications where mass and size constraints are of key significance, such volume of hardware represents a clear disadvantage. Instead of requiring different instruments for each reactor operating range (start-up, ramping-up, and nominal power), a single instrument chain should be desirable. A Wide Range Neutron Detector (WRND) system, combining a classic pulse Counting Channel with a Campbell's theorem based Fluctuation Channel can be implemented for the monitoring and control of a space nuclear reactor. Such an instrument will allow for a reduction in the complexity of space-based nuclear instrumentation and control systems. In this presentation we will discuss the criteria and tradeoffs involved in the development of such a system. We will focus particularly on the characteristics of the System On Chip (SOC) and the DSP board used to implement this instrument.

  7. Practical applications of small-angle neutron scattering.

    PubMed

    Hollamby, Martin J

    2013-07-14

    Recent improvements in beam-line accessibility and technology have led to small-angle neutron scattering (SANS) becoming more frequently applied to materials problems. SANS has been used to study the assembly, dispersion, alignment and mixing of nanoscale condensed matter, as well as to characterise the internal structure of organic thin films, porous structures and inclusions within steel. Using time-resolved SANS, growth mechanisms in materials systems and soft matter phase transitions can also be explored. This review is intended for newcomers to SANS as well as experts. Therefore, the basic knowledge required for its use is first summarised. After this introduction, various examples are given of the types of soft and hard matter that have been studied by SANS. The information that can be extracted from the data is highlighted, alongside the methods used to obtain it. In addition to presenting the findings, explanations are provided on how the SANS measurements were optimised, such as the use of contrast variation to highlight specific parts of a structure. Emphasis is placed on the use of complementary techniques to improve data quality (e.g. using other scattering methods) and the accuracy of data analysis (e.g. using microscopy to separately determine shape and size). This is done with a view to providing guidance on how best to design and analyse future SANS measurements on materials not listed below. PMID:23552189

  8. Practical applications of small-angle neutron scattering.

    PubMed

    Hollamby, Martin J

    2013-07-14

    Recent improvements in beam-line accessibility and technology have led to small-angle neutron scattering (SANS) becoming more frequently applied to materials problems. SANS has been used to study the assembly, dispersion, alignment and mixing of nanoscale condensed matter, as well as to characterise the internal structure of organic thin films, porous structures and inclusions within steel. Using time-resolved SANS, growth mechanisms in materials systems and soft matter phase transitions can also be explored. This review is intended for newcomers to SANS as well as experts. Therefore, the basic knowledge required for its use is first summarised. After this introduction, various examples are given of the types of soft and hard matter that have been studied by SANS. The information that can be extracted from the data is highlighted, alongside the methods used to obtain it. In addition to presenting the findings, explanations are provided on how the SANS measurements were optimised, such as the use of contrast variation to highlight specific parts of a structure. Emphasis is placed on the use of complementary techniques to improve data quality (e.g. using other scattering methods) and the accuracy of data analysis (e.g. using microscopy to separately determine shape and size). This is done with a view to providing guidance on how best to design and analyse future SANS measurements on materials not listed below.

  9. The Use of the Photofission of 238U for a Neutron-Rich Radioactive Ion Beams Generation

    NASA Astrophysics Data System (ADS)

    Szöllős, O.; Kliman, J.

    2003-10-01

    The fission fragments yield for photofission of 238U, induced by bremsstrahlung photons with endpoint energies of 25 and 50MeV was evaluated to estimate the possibility of producing the neutron-rich nuclei. The systematics coming from A.C. Wahl's Zp model 1 for charge distribution of fission fragments were used. Results for xenon and krypton isotopes are compared with experimental data 2 obtained on the DRIBs 3 (Dubna Radioactive Ion Beams) facility for neutron-rich nuclei production in Flerov Laboratory. The fission rate and fission density in production target for metallic uranium and UCx compounds were simulated with Geant4 4 simulation toolkit to design the target geometry, The fission rate dependence on material of the electron stopping target was examined, At nominal beam values on microtron MT-25 (Ie = 20μA, Ee = 25MeV) up to 2.1011 fissions/s could be achieved. Then the production rate of neutron-rich isotopes reaching order of 109s-1. The induced activity in the production target depending on an irradiation time was calculated for radiation protection purposes and target safety estimation. The cumulation of actinide nuclei was also calculated.

  10. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    SciTech Connect

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-14

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E < 12.47% for 99% particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 10{sup 11} n/cm{sup 2}/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  11. Application of gradient elasticity to benchmark problems of beam vibrations

    NASA Astrophysics Data System (ADS)

    Kateb, K. M.; Almitani, K. H.; Alnefaie, K. A.; Abu-Hamdeh, N. H.; Papadopoulos, P.; Askes, H.; Aifantis, E. C.

    2016-04-01

    The gradient approach, specifically gradient elasticity theory, is adopted to revisit certain typical configurations on mechanical vibrations. New results on size effects and scale-dependent behavior not captured by classical elasticity are derived, aiming at illustrating the usefulness of this approach to applications in advanced technologies. In particular, elastic prismatic straight beams in bending are discussed using two different governing equations: the gradient elasticity bending moment equation (fourth order) and the gradient elasticity deflection equation (sixth order). Different boundary/support conditions are examined. One problem considers the free vibrations of a cantilever beam loaded by an end force. A second problem is concerned with a simply supported beam disturbed by a concentrated force in the middle of the beam. Both problems are solved analytically. Exact free vibration frequencies and mode shapes are derived and presented. The difference between the gradient elasticity solution and its classical counterpart is revealed. The size ratio c/L (c denotes internal length and L is the length of the beam) induces significant effects on vibration frequencies. For both beam configurations, it turns out that as the ratio c/L increases, the vibration frequencies decrease, a fact which implies lower beam stiffness. Numerical examples show this behavior explicitly and recover the classical vibration behavior for vanishing size ratio c/L.

  12. Laser-driven particle and photon beams and some applications

    NASA Astrophysics Data System (ADS)

    Ledingham, K. W. D.; Galster, W.

    2010-04-01

    Outstanding progress has been made in high-power laser technology in the last 10 years with laser powers reaching petawatt (PW) values. At present, there are 15 PW lasers built or being built around the world and plans are afoot for new, even higher power, lasers reaching values of exawatt (EW) or even zetawatt (ZW) powers. Petawatt lasers generate electric fields of 1012 V m-1 with a large fraction of the total pulse energy being converted to relativistic electrons with energies reaching in excess of 1 GeV. In turn these electrons result in the generation of beams of protons, heavy ions, neutrons and high-energy photons. These laser-driven particle beams have encouraged many to think of carrying out experiments normally associated with conventional nuclear accelerators and reactors. To this end a number of introductory articles have been written under a trial name 'Laser Nuclear Physics' (Ledingham and Norreys 1999 Contemp. Phys. 40 367, Ledingham et al 2002 Europhys. News. 33 120, Ledingham et al 2003 Science 300 1107, Takabe et al 2001 J. Plasma Fusion Res. 77 1094). However, even greater strides have been made in the last 3 or 4 years in laser technology and it is timely to reassess the potential of laser-driven particle and photon beams. It must be acknowledged right from the outset that to date laser-driven particle beams have yet to compete favourably with conventional nuclear accelerator-generated beams in any way and so this is not a paper comparing laser and conventional accelerators. However, occasionally throughout the paper as a reality check, it will be mentioned what conventional nuclear accelerators can do.

  13. Neutron Imaging at the Oak Ridge National Laboratory: Application to Biological Research

    SciTech Connect

    Bilheux, Hassina Z; Cekanova, Maria; Bilheux, Jean-Christophe; Bailey, William Barton; Keener, Wylie S; Davis, Larry E; Herwig, Kenneth W

    2014-01-01

    The Oak Ridge National Laboratory Neutron Sciences Directorate (NScD) has recently installed a neutron imaging beamline at the High Flux Isotope Reactor (HFIR) cold guide hall. The CG-1D beamline supports a broad range of user research spanning from engineering to material research, energy storage, additive manufacturing, vehicle technologies, archaeology, biology, and plant physiology. The beamline performance (spatial resolution, field of view, etc.) and its utilization for biological research are presented. The NScD is also considering a proposal to build the VENUS imaging beamline (beam port 10) at the Spallation Neutron Source (SNS). Unlike CG-1D which provides cold neutrons, VENUS will offer a broad range of neutron wavelengths, from epithermal to cold, and enhanced contrast mechanisms. This new capability will also enable the imaging of thicker biological samples than is currently available at CG-1D. A brief overview of the VENUS capability for biological research is discussed.

  14. Laser beacon adaptive optics for power beaming applications

    SciTech Connect

    Fugate, R.Q.

    1994-12-31

    This paper discusses the laser beam control system requirements for power beaming applications. Power beaming applications include electric and thermal engine propulsion for orbit transfer, station changing, and recharging batteries. Beam control includes satellite acquisition, high accuracy tracking, higher order atmospheric compensation using adaptive optics, and precision point-ahead. Beam control may also include local laser beam clean-up with a low order adaptive optics system. This paper also presents results of tracking and higher-order correction experiments on astronomical objects. The results were obtained with a laser beacon adaptive optics system at Phillips Laboratory`s Starfire Optical Range near Albuquerque, NM. At a wavelength of 0.85 {mu}m, the author has achieved Strehl ratios of {approximately}0.50 using laser beacons and {approximately}0.65 using natural stars for exposures longer than one minute on objects of {approximately}8{sup th} magnitude. The resulting point spread function has a full width half maximum (FWHM) of 0.13 arcsec.

  15. Scaling of solid state lasers for satellite power beaming applications

    SciTech Connect

    Friedman, H.W.; Albrecht, G.F.; Beach, R.J.

    1994-01-01

    The power requirements for a satellite power beaming laser system depend upon the diameter of the beam director, the performance of the adaptive optics system, and the mission requirements. For an 8 meter beam director and overall Strehl ratio of 50%, a 30 kW laser at 850 nm can deliver an equivalent solar flux to a satellite at geostationary orbit. Advances in Diode Pumped Solid State Lasers (DPSSL) have brought these small, efficient and reliable devices to high average power and they should be considered for satellite power beaming applications. Two solid state systems are described: a diode pumped Alexandrite and diode pumped Thulium doped YAG. Both can deliver high average power at 850 nm in a single aperture.

  16. Scaling of solid state lasers for satellite power beaming applications

    SciTech Connect

    Friedman, H.; Albrecht, G.; Beach, R.

    1994-12-31

    The power requirements for a satellite power beaming laser system depend upon the diameter of the beam director, the performance of the adaptive optics system, and the mission requirements. For an 8 meter beam director and overall Strehl ratio of 50%, a 30 kW laser at 850 nm can deliver an equivalent solar flux to a satellite at geostationary orbit. Advances in Diode Pumped Solid State Lasers (DPSSL) have brought these small, efficient and reliable devices to high average power and they should be considered for satellite power beaming applications. Two solid state systems are described: a diode pumped Alexandrite and diode pumped Thulium doped YAG. Both can deliver high average power at 850 nm in a single aperture.

  17. Intra-beam scattering and its application to ERL

    SciTech Connect

    Fedotov A. V.

    2011-10-16

    Treatment of Coulomb collisions within the beam requires consideration of both large and small angle scattering. Such collisions lead to the Touschek effect and Intrabeam Scattering (IBS). The Touschek effect refers to particle loss as a result of a single collision, where only transfer from the transverse direction into longitudinal plays a role. It is important to consider this effect for ERL design to have an appropriate choice of collimation system. The IBS is a diffusion process which leads to changes of beam distribution but does not necessarily result in a beam loss. Evaluation of IBS in ERLs, where beam distribution is non-Gaussian, requires special treatment. Here we describe the IBS and Touschek effects with application to ERLs.

  18. Personal computer applications in DIII-D neutral beam operation

    SciTech Connect

    Glad, A.S.

    1986-08-01

    An IBM PC AT has been implemented to improve operation of the DIII-D neutral beams. The PC system provides centralization of all beam data with reasonable access for on-line shot-to-shot control and analysis. The PC hardware was configured to interface all four neutral beam host minicomputers, support multitasking, and provide storage for approximately one month's accumulation of beam data. The PC software is composed of commercial packages used for performance and statistical analysis (i.e., LOTUS 123, PC PLOT, etc.), host communications software (i.e., PCLink, KERMIT, etc.), and applications developed software utilizing f-smcapso-smcapsr-smcapst-smcapsr-smcapsa-smcapsn-smcaps and b-smcapsa-smcapss-smcapsIc-smcaps. The objectives of this paper are to describe the implementation of the PC system, the methods of integrating the various software packages, and the scenario for on-line control and analysis.

  19. New applications for high average power beams

    NASA Astrophysics Data System (ADS)

    Neau, E. L.; Turman, B. N.; Patterson, E. L.

    1993-06-01

    The technology base formed by the development of high peak power simulators, laser drivers, FEL's, and ICF drivers from the early 60's through the late 80's is being extended to high average power short-pulse machines with the capabilities of supporting new types of manufacturing processes and performing new roles in environmental cleanup applications. This paper discusses a process for identifying and developing possible commercial applications, specifically those requiring very high average power levels of hundreds of kilowatts to perhaps megawatts. The authors discuss specific technology requirements and give examples of application development efforts. The application development work is directed at areas that can possibly benefit from the high specific energies attainable with short pulse machines.

  20. Three-dimensional calculations of neutron streaming in the beam tubes of the ORNL HFIR (High Flux Isotope Reactor) Reactor

    SciTech Connect

    Childs, R.L.; Rhoades, W.A.; Williams, L.R.

    1988-01-01

    The streaming of neutrons through the beam tubes in High Flux Isotope Reactor at Oak Ridge National Laboratory has resulted in a reduction of the fracture toughness of the reactor vessel. As a result, an evaluation of vessel integrity was undertaken in order to determine if the reactor can be operated again. As a part of this evaluation, three-dimensional neutron transport calculations were performed to obtain fluxes at points of interest in the wall of the vessel. By comparing the calculated and measured activation of dosimetry specimens from the vessel surveillance program, it was determined that the calculated flux shape was satisfactory to transpose the surveillance data to the locations in the vessel. A bias factor was applied to correct for the average C/E ratio of 0.69. 8 refs., 7 figs., 3 tabs.

  1. Optimization of Beam-Shaping Assemblies for BNCS Using the High-Energy Neutron Sources D-D and D-T

    SciTech Connect

    Verbeke, Jerome M.; Chen, Allen S.; Vujic, Jasmina L.; Leung, Ka-Ngo

    2001-06-15

    Boron neutron capture synovectomy is a novel approach for the treatment of rheumatoid arthritis. The goal of the treatment is the ablation of diseased synovial membranes in articulating joints. The treatment of knee joints is the focus of this work. A method was developed, as discussed previously, to predict the dose distribution in a knee joint from any neutron and photon beam spectra incident on the knee. This method is validated and used to design moderators for the deuterium-deuterium (D-D) and deuterium-tritium (D-T) neutron sources. Treatment times >2 h were obtained with the D-D reaction. They could potentially be reduced if the {sup 10}B concentration in the synovium was increased. For D-T neutrons, high therapeutic ratios and treatment times <5 min were obtained for neutron yields of 10{sup 14} s{sup -1}. This treatment time makes the D-T reaction attractive for boron neutron capture synovectomy.

  2. A method for measuring tissue-equivalent dose using a pin diode and activation foil in epithermal neutron beams with EN < 100 keV.

    PubMed

    Carolan, Martin G; Rosenfeld, Anatoly B

    2006-01-01

    Silicon (Si) pin diodes can be used for neutron dosimetry by observing the change in forward bias voltage caused by neutron induced displacement damage in the diode junction. Pin diode energy response depends on Si displacement damage KERMA (K(Si)). It is hypothesised that tissue-equivalent (TE) neutron dose could be expressed as a linear combination of K(Si) and foil activation terms. Monte Carlo simulations (MCNP) of parallel monoenergetic neutron beams incident on a cylindrical TE phantom were used to calculate TE dose, K(Si) and Au, Cu and Mn foil activations along the central axis of the phantom. For spectra with neutron energies <100 keV, it is possible to estimate the TE kerma based on silicon damage kerma and Cu or Mn foil measurements. More accurate estimates are possible for spectra where the maximum neutron energy does not exceed 30 keV. PMID:16644975

  3. A high repetition rate plasma focus for neutron interrogation applications

    NASA Astrophysics Data System (ADS)

    Bures, Brian; Krishnan, Mahadevan; James, Colt; Madden, Robert; Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin; Lane, Stephen

    2011-10-01

    A fast pulsed neutron source enables identification and ranging of contraband nuclear material using time-of-flight separation of the probe neutron pulse from the fission induced emission quanta. Alameda Applied Sciences Corporation has demonstrated a 1 Hz plasma focus neutron source that uses an impedance matching transformer to better couple the power from the driver to the dynamic pinch load. For a 24 kV primary charge, the system produces a 61 kA peak current with a neutron yield up to 5 ×105 neutrons/pulse at 1 Hz. Experiments are described in which induced 845 keV gamma emission from iron targets (by 2.45 MeV DD neutrons) was separated (by time of flight) from the 20-30 ns probe neutron pulses. Monte Carlo simulations are used to optimize the concept for a fieldable system. Work supported by US Department of Homeland Security (DNDO) and by the US Air Force (KAFB).

  4. Production of beams of neutron-rich nuclei between Ca and Ni using the ion-guide technique

    SciTech Connect

    Perajarvi, K.; Cerny, J.; Hager, U.; Hakala, J.; Huikari, J.; Jokinen, A.; Karvonen, P.; Kurpeta, J.; Lee, D.; Moore, I.; Penttila, H.; Popov, A.; Aysto, J.

    2004-09-28

    Since several elements between Z = 20-28 are refractory in their nature, their neutron-rich isotopes are rarely available as low energy Radioactive Ion Beams (RIB) in ordinary Isotope Separator On-Line facilities [1-4]. These low energy RIBs would be especially interesting to have available under conditions which allow high-resolution beta-decay spectroscopy, ion-trapping and laser-spectroscopy. As an example, availability of these beams would open a way for research which could produce interesting and important data on neutron-rich nuclei around the doubly magic {sup 78}Ni. One way to overcome the intrinsic difficulty of producing these beams is to rely on the chemically unselective Ion Guide Isotope Separator On-Line (IGISOL) technique [5]. Quasi- and deep-inelastic reactions, such as {sup 197}Au({sup 65}Cu,X)Y, could be used to produce these nuclei in existing IGISOL facilities, but before they can be successfully incorporated into the IGISOL concept their kinematics must be well understood. Therefore the reaction kinematics part of this study was first performed at the Lawrence Berkeley National Laboratory using its 88'' cyclotron and, based on those results, a specialized target chamber was built[6]. The target chamber shown in Fig. 1 was recently tested on-line at the Jyvaaskylaa IGISOL facility. Yields of mass-separated radioactive projectile-like species such as {sup 62,63}Co are about 0.8 ions/s/pnA, corresponding to about 0.06 % of the total IGISOL efficiency for the products that hit the Ni-degrader. (The current maximum 443 MeV {sup 65}Cu beam intensity at Jyvaaskylaa is about 20 pnA.) This total IGISOL efficiency is a product of two coupled loss factors, namely inadequate thermalization and the intrinsic IGISOL efficiency. In our now tested chamber, about 9 % of the Co recoils are thermalized in the owing He gas (p{sub He}=300 mbar) and about 0.7 % of them are converted into the mass-separated ion beams. In the future, both of these physical

  5. LASER APPLICATIONS: H- BEAM PHOTO-DETACHMENT AND PUSH BUTTON DIAGNOSTICS

    SciTech Connect

    Liu, Yun

    2012-01-01

    The laser based nonintrusive H- beam diagnostics and laser assisted H- beam stripping technologies have been developed at the Spallation Neutron Source (SNS). This paper reviews the present status of the SNS laser based diagnostics and the recent R&D progress on the fiber transmission of laser pulses and power enhancement optical cavity which will be used in diagnostics and laser stripping.

  6. ALL NATURAL COMPOSITE SANDWICH BEAMS FOR STRUCTURAL APPLICATIONS. (R829576)

    EPA Science Inventory

    As part of developing an all natural composite roof for housing application,
    structural panels and unit beams were manufactured out of soybean oil based resin
    and natural fibers (flax, cellulose, pulp, recycled paper, chicken feathers)
    using vacuum assisted resin tran...

  7. High efficiency solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, G. A.

    1995-01-01

    Understanding solar cell response to pulsed laser outputs is important for the evaluation of power beaming applications. The time response of high efficiency GaAs and silicon solar cells to a 25 nS monochromatic pulse input is described. The PC-1D computer code is used to analyze the cell current during and after the pulse for various conditions.

  8. ELIMED, future hadrontherapy applications of laser-accelerated beams

    NASA Astrophysics Data System (ADS)

    Cirrone, Giuseppe A. P.; Carpinelli, Massimo; Cuttone, Giacomo; Gammino, Santo; Bijan Jia, S.; Korn, Georg; Maggiore, Mario; Manti, Lorenzo; Margarone, Daniele; Prokupek, Jan; Renis, Marcella; Romano, Francesco; Schillaci, Francesco; Tomasello, Barbara; Torrisi, Lorenzo; Tramontana, Antonella; Velyhan, Andriy

    2013-12-01

    Laser-ion acceleration has recently gained a great interest as an alternative to conventional and more expensive acceleration techniques. These ion beams have desirable qualities such as small source size, high luminosity and small emittance to be used in different fields as Nuclear Physics, Medical Physics, etc. This is very promising specially for the future perspective of a new concept of hadrontherapy based on laser-based devices could be developed, replacing traditional accelerating machines. Before delivering laser-driven beams for treatments they have to be handled, cleaned from unwanted particles and characterized in order to have the clinical requirements. In fact ion energy spectra have exponential trend, almost 100% energy spread and a wide angular divergence which is the biggest issue in the beam transport and, hence, in a wider use of this technology. In order to demonstrate the clinical applicability of laser-driven beams new collaboration between ELI-Beamlines project researchers from Prague (Cz) and a INFN-LNS group from Catania (I) has been already launched and scientists from different countries have already express their will in joining the project. This cooperation has been named ELIMED (MEDical application at ELIBeamlines) and will take place inside the ELI-Beamlines infrastructure located in Prague. This work describes the schedule of the ELIMED project and the design of the energy selector which will be realized at INFN-LNS. The device is an important part of the whole transport beam line which will be realised in order to make the ion beams suitable for medical applications.

  9. Neutron-Induced Partial Gamma-Ray Cross-Section Measurements on 238U Using a Monoenergetic and Pulsed Beam at TUNL

    NASA Astrophysics Data System (ADS)

    Hutcheson, A.; Pedroni, R. S.; Weisel, G. J.; Becker, J. A.; Fotiades, N.; Lantuejoul, I.

    2005-04-01

    An experimental program is being developed at TUNL to study (n,2n) excitation functions on actinide nuclei using monoenergetic neutrons in the 5 to 18 MeV energy range with the goal of improving the partial cross-section data for the NNSA Stockpile Stewardship Program. Measurements have been performed on a ^238U target in the TUNL shielded neutron source area using a pulsed neutron beam with incident neutron energies of 6, 8, 10, and 14 MeV. The emitted gamma rays were measured using different types of HPGe detectors. The pulsed beam permitted the use of time-of-flight techniques to distinguish (n,2n) events from background events. Experimental techniques and analysis of the measurements will be presented.

  10. Analyses of the reflector tank, cold source, and beam tube cooling for ANS reactor. [Advanced Neutron Source (ANS)

    SciTech Connect

    Marland, S. )

    1992-07-01

    This report describes my work as an intern with Martin Marietta Energy Systems, Inc., in the summer of 1991. I was assigned to the Reactor Technology Engineering Department, working on the Advanced Neutron Source (ANS). My first project was to select and analyze sealing systems for the top of the diverter/reflector tank. This involved investigating various metal seals and calculating the forces necessary to maintain an adequate seal. The force calculations led to an analysis of several bolt patterns and lockring concepts that could be used to maintain a seal on the vessel. Another project involved some pressure vessel stress calculations and the calculation of the center of gravity for the cold source assembly. I also completed some sketches of possible cooling channel patterns for the inner vessel of the cold source. In addition, I worked on some thermal design analyses for the reflector tank and beam tubes, including heat transfer calculations and assisting in Patran and Pthermal analyses. To supplement the ANS work, I worked on other projects. I completed some stress/deflection analyses on several different beams. These analyses were done with the aid of CAASE, a beam-analysis software package. An additional project involved bending analysis on a carbon removal system. This study was done to find the deflection of a complex-shaped beam when loaded with a full waste can.

  11. Fricke-gel dosimetry in epithermal or thermal neutron beams of a research reactor

    NASA Astrophysics Data System (ADS)

    Gambarini, G.; Artuso, E.; Giove, D.; Volpe, L.; Agosteo, S.; Barcaglioni, L.; Campi, F.; Garlati, L.; Pola, A.; Durisi, E.; Borroni, M.; Carrara, M.; Klupak, V.; Marek, M.; Viererbl, L.; Vins, M.; d'Errico, F.

    2015-11-01

    Fricke-xylenol-orange gel has shown noticeable potentiality for in-phantom dosimetry in epithermal or thermal neutron fields with very high fluence rate, as those characteristic of nuclear research reactors. Fricke gels in form of layers give the possibility of achieving spatial distribution of gamma dose, fast neutron dose and dose due to charged particles generated by thermal neutron reactions. The thermal neutron fluence has been deduced from the dose coming from the charge particles emitted by neutron reactions with the isotope 10B. Some measurements have been performed for improving the information on the relative sensitivity of Fricke gel dosimeters to the particles produced by 10B reactions, because at present the precision of dose evaluations is limited by the scanty knowledge about the dependence of the dosimeter sensitivity on the radiation LET. For in-air measurements, the dosimeter material can produce an enhancement of thermal neutron fluence. Measurements and Monte Carlo calculations have been developed to investigate the importance of this effect.

  12. SciDAC Advances and Applications in Computational Beam Dynamics

    SciTech Connect

    Ryne, R.; Abell, D.; Adelmann, A.; Amundson, J.; Bohn, C.; Cary, J.; Colella, P.; Dechow, D.; Decyk, V.; Dragt, A.; Gerber, R.; Habib, S.; Higdon, D.; Katsouleas, T.; Ma, K.-L.; McCorquodale, P.; Mihalcea, D.; Mitchell, C.; Mori, W.; Mottershead, C.T.; Neri, F.; Pogorelov, I.; Qiang, J.; Samulyak, R.; Serafini, D.; Shalf, J.; Siegerist, C.; Spentzouris, P.; Stoltz, P.; Terzic, B.; Venturini, M.; Walstrom, P.

    2005-06-26

    SciDAC has had a major impact on computational beam dynamics and the design of particle accelerators. Particle accelerators--which account for half of the facilities in the DOE Office of Science Facilities for the Future of Science 20 Year Outlook--are crucial for US scientific, industrial, and economic competitiveness. Thanks to SciDAC, accelerator design calculations that were once thought impossible are now carried routinely, and new challenging and important calculations are within reach. SciDAC accelerator modeling codes are being used to get the most science out of existing facilities, to produce optimal designs for future facilities, and to explore advanced accelerator concepts that may hold the key to qualitatively new ways of accelerating charged particle beams. In this poster we present highlights from the SciDAC Accelerator Science and Technology (AST) project Beam Dynamics focus area in regard to algorithm development, software development, and applications.

  13. An Evaluation of Grazing-Incidence Optics for Neutron Imaging

    NASA Technical Reports Server (NTRS)

    Gubarev, M. V.; Ramsey, B. D.; Engelhaupt, D. E.; Burgess, J.; Mildner, D. F. R.

    2007-01-01

    The focusing capabilities of neutron imaging optic based on the Wolter-1 geometry have been successfully demonstrated with a beam of long wavelength neutrons with low angular divergence.. A test mirror was fabricated using an electroformed nickel replication process at Marshall Space Flight Center. The neutron current density gain at the focal spot of the mirror is found to be at least 8 for neutron wavelengths in the range from 6 to 20 A. Possible applications of the optics are briefly discussed.

  14. Progress in bright ion beams for industry, medicine and fusion at LBNL

    SciTech Connect

    Kwan, Joe W.

    2002-05-31

    Recent progresses at LBNL in developing ion beams for industry, radiation therapy and inertial fusion applications were discussed. The highlights include ion beam lithography, boron neutron capture therapy (BNCT), and heavy ion fusion (HIF) drivers using multiple linacs.

  15. New sources and instrumentation for neutron science

    NASA Astrophysics Data System (ADS)

    Gil, Alina

    2011-04-01

    Neutron-scattering research has a lot to do with our everyday lives. Things like medicine, food, electronics, cars and airplanes have all been improved by neutron-scattering research. Neutron research also helps scientists improve materials used in a multitude of different products, such as high-temperature superconductors, powerful lightweight magnets, stronger, lighter plastic products etc. Neutron scattering is one of the most effective ways to obtain information on both, the structure and the dynamics of condensed matter. Most of the world's neutron sources were built decades ago, and although the uses and demand for neutrons have increased throughout the years, few new sources have been built. The new construction, accelerator-based neutron source, the spallation source will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. In this paper it will be described what neutrons are and what unique properties make them useful for science, how spallation source is designed to produce neutron beams and the experimental instruments that will use those beams. Finally, it will be described how past neutron research has affected our everyday lives and what we might expect from the most exciting future applications.

  16. Intra-beam scattering and its application to ERL

    SciTech Connect

    Fedotov, A.

    2011-10-16

    Treatment of Coulomb collisions within the beam requires consideration of both large and small angle scattering. Such collisions lead to the Touschek effect and Intrabeam Scattering (IBS). The Touschek effect refers to particle loss as a result of a single collision, where only transfer from the transverse direction into longitudinal plays a role. It is important to consider this effect for ERL design to have an appropriate choice of collimation system. The IBS is a diffusion process which leads to changes of beam distribution but does not necessarily result in a beam loss. Evaluation of IBS in ERLs, where beam distribution is non-Gaussian, requires special treatment. Here we describe the IBS and Touschek effects with application to ERLs. In circular accelerators both the Touschek effect and IBS were found important. The generalized formulas for Touschek calculations are available and are already being used in advanced tracking simulations of several ERL-based projects. The IBS (which is diffusion due to multiple Coulomb scattering) is not expected to cause any significant effect on beam distribution in ERLs, unless one considers very long transport of high-brightness beams at low energies. Both large and small-angle Coulomb scattering can contribute to halo formation in future ERLs with high-brightness beams, as follows from simple order-of-magnitude estimates. In this report, a test comparison between 'local' and 'sliced' IBS models within the BET ACOOL code was presented for an illustrative ERL distribution. We also presented accumulated current loss distribution due to Touschek scattering for design parameters of ERL proposed for the eRHIC project, as well as scaling for multi-pass ERLs.

  17. Characterization of neutron calibration fields at the TINT's 50 Ci americium-241/beryllium neutron irradiator

    NASA Astrophysics Data System (ADS)

    Liamsuwan, T.; Channuie, J.; Ratanatongchai, W.

    2015-05-01

    Reliable measurement of neutron radiation is important for monitoring and protection in workplace where neutrons are present. Although Thailand has been familiar with applications of neutron sources and neutron beams for many decades, there is no calibration facility dedicated to neutron measuring devices available in the country. Recently, Thailand Institute of Nuclear Technology (TINT) has set up a multi-purpose irradiation facility equipped with a 50 Ci americium-241/beryllium neutron irradiator. The facility is planned to be used for research, nuclear analytical techniques and, among other applications, calibration of neutron measuring devices. In this work, the neutron calibration fields were investigated in terms of neutron energy spectra and dose equivalent rates using Monte Carlo simulations, an in-house developed neutron spectrometer and commercial survey meters. The characterized neutron fields can generate neutron dose equivalent rates ranging from 156 μSv/h to 3.5 mSv/h with nearly 100% of dose contributed by neutrons of energies larger than 0.01 MeV. The gamma contamination was less than 4.2-7.5% depending on the irradiation configuration. It is possible to use the described neutron fields for calibration test and routine quality assurance of neutron dose rate meters and passive dosemeters commonly used in radiation protection dosimetry.

  18. Controlling neutron orbital angular momentum.

    PubMed

    Clark, Charles W; Barankov, Roman; Huber, Michael G; Arif, Muhammad; Cory, David G; Pushin, Dmitry A

    2015-09-24

    The quantized orbital angular momentum (OAM) of photons offers an additional degree of freedom and topological protection from noise. Photonic OAM states have therefore been exploited in various applications ranging from studies of quantum entanglement and quantum information science to imaging. The OAM states of electron beams have been shown to be similarly useful, for example in rotating nanoparticles and determining the chirality of crystals. However, although neutrons--as massive, penetrating and neutral particles--are important in materials characterization, quantum information and studies of the foundations of quantum mechanics, OAM control of neutrons has yet to be achieved. Here, we demonstrate OAM control of neutrons using macroscopic spiral phase plates that apply a 'twist' to an input neutron beam. The twisted neutron beams are analysed with neutron interferometry. Our techniques, applied to spatially incoherent beams, demonstrate both the addition of quantum angular momenta along the direction of propagation, effected by multiple spiral phase plates, and the conservation of topological charge with respect to uniform phase fluctuations. Neutron-based studies of quantum information science, the foundations of quantum mechanics, and scattering and imaging of magnetic, superconducting and chiral materials have until now been limited to three degrees of freedom: spin, path and energy. The optimization of OAM control, leading to well defined values of OAM, would provide an additional quantized degree of freedom for such studies.

  19. Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Shin, Jae Won; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Min, Kyung Joo; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

    2015-10-01

    Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑ Φ(En) σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑ Φ(En) σ(En) along with other parameters in a neutron activation method.

  20. Twisting Neutron Waves

    NASA Astrophysics Data System (ADS)

    Pushin, Dmitry

    Most waves encountered in nature can be given a ``twist'', so that their phase winds around an axis parallel to the direction of wave propagation. Such waves are said to possess orbital angular momentum (OAM). For quantum particles such as photons, atoms, and electrons, this corresponds to the particle wavefunction having angular momentum of Lℏ along its propagation axis. Controlled generation and detection of OAM states of photons began in the 1990s, sparking considerable interest in applications of OAM in light and matter waves. OAM states of photons have found diverse applications such as broadband data multiplexing, massive quantum entanglement, optical trapping, microscopy, quantum state determination and teleportation, and interferometry. OAM states of electron beams have been used to rotate nanoparticles, determine the chirality of crystals and for magnetic microscopy. Here I discuss the first demonstration of OAM control of neutrons. Using neutron interferometry with a spatially incoherent input beam, we show the addition and conservation of quantum angular momenta, entanglement between quantum path and OAM degrees of freedom. Neutron-based quantum information science heretofore limited to spin, path, and energy degrees of freedom, now has access to another quantized variable, and OAM modalities of light, x-ray, and electron beams are extended to a massive, penetrating neutral particle. The methods of neutron phase imprinting demonstrated here expand the toolbox available for development of phase-sensitive techniques of neutron imaging. Financial support provided by the NSERC Create and Discovery programs, CERC and the NIST Quantum Information Program is acknowledged.

  1. High flux compact neutron generators

    SciTech Connect

    Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

    2001-06-15

    Compact high flux neutron generators are developed at the Lawrence Berkeley National Laboratory. The neutron production is based on D-D or D-T reaction. The deuterium or tritium ions are produced from plasma using either a 2 MHz or 13.56 MHz radio frequency (RF) discharge. RF-discharge yields high fraction of atomic species in the beam which enables higher neutron output. In the first tube design, the ion beam is formed using a multiple hole accelerator column. The beam is accelerated to energy of 80 keV by means of a three-electrode extraction system. The ion beam then impinges on a titanium target where either the 2.4 MeV D-D or 14 MeV D-T neutrons are generated. The MCNP computation code has predicted a neutron flux of {approximately}10{sup 11} n/s for the D-D reaction at beam intensity of 1.5 A at 150 kV. The neutron flux measurements of this tube design will be presented. Recently new compact high flux tubes are being developed which can be used for various applications. These tubes also utilize RF-discharge for plasma generation. The design of these tubes and the first measurements will be discussed in this presentation.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  3. Deformation of the very neutron-deficient rare-earth nuclei produced with the SPIRAL 76Kr radioactive beam and studied with EXOGAM + DIAMANT

    SciTech Connect

    Redon, N.; Guinet, D.; Lautesse, Ph.; Meyer, M.; Rosse, B.; Stezowski, O.; France, G. de; Casandjian, J. M.

    2004-02-27

    The structure of the very neutron-deficient rare-earth nuclei has been investigated in the first experiment with the EXOGAM gamma array coupled to the DIAMANT light charged particle detector using radioactive beam of 76Kr delivered by the SPIRAL facility. Very neutron-deficient Pr, Nd and Pm isotopes have been populated at rather high spin by the reaction 76Kr + 58Ni at a beam energy of 328 MeV. We report here the first results of this experiment.

  4. The Physics and Applications of High Brightness Electron Beams

    NASA Astrophysics Data System (ADS)

    Palumbo, Luigi; Rosenzweig, J.; Serafini, Luca

    2007-09-01

    Plenary sessions. RF deflector based sub-Ps beam diagnostics: application to FEL and advanced accelerators / D. Alesini. Production of fermtosecond pulses and micron beam spots for high brightness electron beam applications / S.G. Anderson ... [et al.]. Wakefields of sub-picosecond electron bunches / K.L.F. Bane. Diamond secondary emitter / I. Ben-Zvi ... [et al.]. Parametric optimization for an X-ray free electron laser with a laser wiggler / R. Bonifacio, N. Piovella and M.M. Cola. Needle cathodes for high-brightness beams / C.H. Boulware ... [et al.]. Non linear evolution of short pulses in FEL cascaded undulators and the FEL harmonic cascade / L. Giannessi and P. Musumeci. High brightness laser induced multi-meV electron/proton sources / D. Giulietti ... [et al.]. Emittance limitation of a conditioned beam in a strong focusing FEL undulator / Z. Huang, G. Stupakov and S. Reiche. Scaled models: space-charge dominated electron storage rings / R.A. Kishek ... [et al.]. High brightness beam applications: energy recovered linacs / G.A. Krafft. Maximizing brightness in photoinjectors / C. Limborg-Deprey and H. Tomizawa. Ultracold electron sources / O.J. Luiten ... [et al.]. Scaling laws of structure-based optical accelerators / A. Mizrahi, V. Karagodsky and L. Schächter. High brightness beams-applications to free-electron lasers / S. Reiche. Conception of photo-injectors for the CTF3 experiment / R. Roux. Superconducting RF photoinjectors: an overview / J. Sekutowicz. Status and perspectives of photo injector developments for high brightness beams / F. Stephan. Results from the UCLA/FNLP underdense plasma lens experiment / M.C. Thompson ... [et al.]. Medical application of multi-beam compton scattering monochromatic tunable hard X-ray source / M. Uesaka ... [et al.]. Design of a 2 kA, 30 fs RF-photoinjector for waterbag compression / S.B. Van Der Geer, O.J. Luiten and M.J. De Loos. Proposal for a high-brightness pulsed electron source / M. Zolotorev ... [et al

  5. Cryo-focused-ion-beam applications in structural biology.

    PubMed

    Rigort, Alexander; Plitzko, Jürgen M

    2015-09-01

    The ability to precisely control the preparation of biological samples for investigations by electron cryo-microscopy is becoming increasingly important for ultrastructural imaging in biology. Precision machining instruments such as the focused ion beam microscope (FIB) were originally developed for applications in materials science. However, today we witness a growing use of these tools in the life sciences mainly due to their versatility, since they can be used both as manipulation and as imaging devices, when complemented with a scanning electron microscope (SEM). The advent of cryo-preparation equipment and accessories made it possible to pursue work on frozen-hydrated biological specimens with these two beam (FIB/SEM) instruments. In structural biology, the cryo-FIB can be used to site-specifically thin vitrified specimens for transmission electron microscopy (TEM) and tomography. Having control over the specimen thickness is a decisive factor for TEM imaging, as the thickness of the object under scrutiny determines the attainable resolution. Besides its use for TEM preparation, the FIB/SEM microscope can be additionally used to obtain three-dimensional volumetric data from biological specimens. The unique combination of an imaging and precision manipulation tool allows sequentially removing material with the ion beam and imaging the milled block faces by scanning with the electron beam, an approach known as FIB/SEM tomography. This review covers both fields of cryo-FIB applications: specimen preparation for TEM cryo-tomography and volume imaging by cryo-FIB/SEM tomography.

  6. Exploration mission enhancements possible with power beaming. [Space Applications Power Beaming

    SciTech Connect

    Bamberger, J.A.; Coomes, E.P. ); Segna, D.R. )

    1990-10-01

    A key factor in the exploration and development of the space frontier is the availability of energy where and when it is needed. Currently all space satellites and platforms include self-contained power systems that supply the energy necessary to accomplish mission objectives. An alternative approach is to couple advanced high power system with energy beam transmitters and energy receivers to form an infrastructure of a space power utility where a central power system provides power to multiple users. Major space activities, such as low Earth orbit space commercialization and the colonization of the Moon or Mars, would benefit significantly from a central power generation and transmission system. This paper describes the power-beaming concept and system components as applied to space power generation and distribution in support of the Space Exploration Initiative. Beam-power scenarios are discussed including commonality of systems and hardware with cargo transport vehicles, power beaming from orbit to stationary and mobile users on the Lunar and Mars surfaces, and other surface applications. 6 refs.

  7. Study of suitability of Fricke-gel-layer dosimeters for in-air measurements to characterise epithermal/thermal neutron beams for NCT.

    PubMed

    Gambarini, G; Artuso, E; Giove, D; Felisi, M; Volpe, L; Barcaglioni, L; Agosteo, S; Garlati, L; Pola, A; Klupak, V; Viererbl, L; Vins, M; Marek, M

    2015-12-01

    The reliability of Fricke gel dosimeters in form of layers for measurements aimed at the characterization of epithermal neutron beams has been studied. By means of dosimeters of different isotopic composition (standard, containing (10)B or prepared with heavy water) placed against the collimator exit, the spatial distribution of gamma and fast neutron doses and of thermal neutron fluence are attained. In order to investigate the accuracy of the results obtained with in-air measurements, suitable MC simulations have been developed and experimental measurements have been performed utilizing Fricke gel dosimeters, thermoluminescence detectors and activation foils. The studies were related to the epithermal beam designed for BNCT irradiations at the research reactor LVR-15 (Řež). The results of calculation and measurements have revealed good consistency of gamma dose and fast neutron 2D distributions obtained with gel dosimeters in form of layers. In contrast, noticeable modification of thermal neutron fluence is caused by the neutron moderation produced by the dosimeter material. Fricke gel dosimeters in thin cylinders, with diameter not greater than 3mm, have proved to give good results for thermal neutron profiling. For greater accuracy of all results, a better knowledge of the dependence of gel dosimeter sensitivity on radiation LET is needed.

  8. Commercial Clinical Application of Boron Neutron Capture Therapy

    SciTech Connect

    N /A

    1999-09-03

    CRADA No. 95-CR-09 among the LITCO--now Bechtel BWXT Idaho, LLC; a private company, Neutron Therapies Limited Liability Company, NTL formerly Ionix Corporation; and Washington State University was established in 1996 to further the development of BNCT. NTL has established a laboratory for the synthesis, under US FDA approved current Good Manufacturing Practices (cGMP) guidelines, of key boron intermediates and final boron agents for BNCT. The company has focused initially on the development of the compound GB-10 (Na{sub 2}B{sub 10}H{sub 10}) as the first boron agent of interest. An Investigational New Drug (IND) application for GB-10 has been filed and approved by the FDA for a Phase I human biodistribution trial in patients with non-small cell lung cancer and glioblastoma multiforme at UW under the direction of Professor Keith Stelzer, Principal Investigator (PI). These trials are funded by NTL under a contract with the UW, Department of Radiation Oncology, and the initial phases are nearing completion. Initial results show that boron-10 concentrations on the order of 100 micrograms per gram (100 ppm) can be achieved and maintained in blood with no indication of toxicity.

  9. Simulation of neutron displacement damage in bipolar junction transistors using high-energy heavy ion beams.

    SciTech Connect

    Doyle, Barney Lee; Buller, Daniel L.; Hjalmarson, Harold Paul; Fleming, Robert M; Bielejec, Edward Salvador; Vizkelethy, Gyorgy

    2006-12-01

    Electronic components such as bipolar junction transistors (BJTs) are damaged when they are exposed to radiation and, as a result, their performance can significantly degrade. In certain environments the radiation consists of short, high flux pulses of neutrons. Electronics components have traditionally been tested against short neutron pulses in pulsed nuclear reactors. These reactors are becoming less and less available; many of them were shut down permanently in the past few years. Therefore, new methods using radiation sources other than pulsed nuclear reactors needed to be developed. Neutrons affect semiconductors such as Si by causing atomic displacements of Si atoms. The recoiled Si atom creates a collision cascade which leads to displacements in Si. Since heavy ions create similar cascades in Si we can use them to create similar damage to what neutrons create. This LDRD successfully developed a new technique using easily available particle accelerators to provide an alternative to pulsed nuclear reactors to study the displacement damage and subsequent transient annealing that occurs in various transistor devices and potentially qualify them against radiation effects caused by pulsed neutrons.

  10. DEVELOPMENT OF ACCELERATOR DATA REPORTING SYSTEM AND ITS APPLICATION TO TREND ANALYSIS OF BEAM CURRENT DATA

    SciTech Connect

    Padilla, M.J.; Blokland, W.

    2009-01-01

    Detailed ongoing information about the ion beam quality is crucial to the successful operation of the Spallation Neutron Source at Oak Ridge National Laboratory. In order to provide the highest possible neutron production time, ion beam quality is monitored to isolate possible problems or performance-related issues throughout the accelerator and accumulator ring. For example, beam current monitor (BCM) data is used to determine the quality of the beam transport through the accelerator. In this study, a reporting system infrastructure was implemented and used to generate a trend analysis report of the BCM data. The BCM data was analyzed to facilitate the identifi cation of monitor calibration issues, beam trends, beam abnormalities, beam deviations and overall beam quality. A comparison between transformed BCM report data and accelerator log entries shows promising results which represent correlations between the data and changes made within the accelerator. The BCM analysis report is one of many reports within a system that assist in providing overall beam quality information to facilitate successful beam operation. In future reports, additional data manipulation functions and analysis can be implemented and applied. Built-in and user-defi ned analytic functions are available throughout the reporting system and can be reused with new data.

  11. Nested Focusing Optics for Compact Neutron Sources

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center, the Massachusetts Institute of Technology (MIT), and the University of Alabama Huntsville (UAH) have developed novel neutron grazing incidence optics for use with small-scale portable neutron generators. The technology was developed to enable the use of commercially available neutron generators for applications requiring high flux densities, including high performance imaging and analysis. Nested grazing incidence mirror optics, with high collection efficiency, are used to produce divergent, parallel, or convergent neutron beams. Ray tracing simulations of the system (with source-object separation of 10m for 5 meV neutrons) show nearly an order of magnitude neutron flux increase on a 1-mm diameter object. The technology is a result of joint development efforts between NASA and MIT researchers seeking to maximize neutron flux from diffuse sources for imaging and testing applications.

  12. SU-E-T-403: Measurement of the Neutron Ambient Dose Equivalent From the TrueBeam Linac Head and Varian 2100 Clinac

    SciTech Connect

    Harvey, M; Pollard, J; Wen, Z; Gao, S

    2014-06-01

    Purpose: High-energy x-ray therapy produces an undesirable source of stray neutron dose to healthy tissues, and thus, poses a risk for second cancer induction years after the primary treatment. Hence, the purpose of this study was to measure the neutron ambient dose equivalent, H*(10), produced from the TrueBeam and Varian 2100 linac heads, respectively. Of particular note is that there is no measured data available in the literature on H*(10) production from the TrueBeam treatment head. Methods: Both linacs were operated in flattening filter mode using a 15 MV x-ray beam on TrueBeam and an 18 MV x-ray beam for the Varian 2100 Clinac with the jaws and multileaf collimators in the fully closed position. A dose delivery rate of 600 MU/min was delivered on the TrueBeam and the Varian 2100 Clinac, respectively and the H*(10) rate was measured in triplicate using the WENDI-2 detector located at multiple positions including isocenter and longitudinal (gun-target) to the isocenter. Results: For each measurement, the H*(10) rate was relatively constant with increasing distance away from the isocenter with standard deviations on the order of a tenth of a mSv/h or less for the given beam energy. In general, fluctuations in the longitudinal H*(10) rate between the anterior-posterior couch directions were approximately a percent for both beam energies. Conclusion: Our preliminary results suggest an H*(10) rate of about 30 mSv/h (40 mSv/h) or less for TrueBeam (Varian Clinac 2100) for all measurements considered in this study indicating a relatively low contribution of produced secondary neutrons to the primary therapeutic beam.

  13. Medical applications of nuclear physics and heavy-ion beams

    SciTech Connect

    Alonso, Jose R.

    2000-08-01

    Isotopes and accelerators, hallmarks of nuclear physics, are finding increasingly sophisticated and effective applications in the medical field. Diagnostic and therapeutic uses of radioisotopes are now a $10B/yr business worldwide, with over 10 million procedures and patient studies performed every year. This paper will discuss the use of isotopes for these applications. In addition, beams of protons and heavy ions are being more and more widely used clinically for treatment of malignancies. To be discussed here as well will be the rationale and techniques associated with charged-particle therapy, and the progress in implementation and optimization of these technologies for clinical use.

  14. Application of neutron interrogation techniques to corrosion detection

    NASA Technical Reports Server (NTRS)

    Birt, E. A.; Namkung, M.; Vulcan, W.; Welsh, R. E.

    1991-01-01

    This paper discusses a technique which may be able to detect corrosion by determining the presence of oxygen at the corroded site via a neutron inelastic gamma reaction. Initial experiments have been performed using a Pu-239/Be neutron source and a NaI(T1) gamma-ray detector. From the results it was concluded that a 1 mm thickness of aluminum oxide would not be detected.

  15. Beam manipulation with velocity bunching for PWFA applications

    NASA Astrophysics Data System (ADS)

    Pompili, R.; Anania, M. P.; Bellaveglia, M.; Biagioni, A.; Bisesto, F.; Chiadroni, E.; Cianchi, A.; Croia, M.; Curcio, A.; Di Giovenale, D.; Ferrario, M.; Filippi, F.; Galletti, M.; Gallo, A.; Giribono, A.; Li, W.; Marocchino, A.; Mostacci, A.; Petrarca, M.; Petrillo, V.; Di Pirro, G.; Romeo, S.; Rossi, A. R.; Scifo, J.; Shpakov, V.; Vaccarezza, C.; Villa, F.; Zhu, J.

    2016-09-01

    The activity of the SPARC_LAB test-facility (LNF-INFN, Frascati) is currently focused on the development of new plasma-based accelerators. Particle accelerators are used in many fields of science, with applications ranging from particle physics research to advanced radiation sources (e.g. FEL). The demand to accelerate particles to higher and higher energies is currently limited by the effective efficiency in the acceleration process that requires the development of km-size facilities. By increasing the accelerating gradient, the compactness can be improved and costs reduced. Recently, the new technique which attracts main efforts relies on plasma acceleration. In the following, the current status of plasma-based activities at SPARC_LAB is presented. Both laser- and beam-driven schemes will be adopted with the aim to provide an adequate accelerating gradient (1-10 GV/m) while preserving the brightness of the accelerated beams to the level of conventional photo-injectors. This aspect, in particular, requires the use of ultra-short (< 100 fs) electron beams, consisting in one or more bunches. We show, with the support of simulations and experimental results, that such beams can be produced using RF compression by velocity-bunching.

  16. Electron-beam generated plasmas for processing applications

    NASA Astrophysics Data System (ADS)

    Meger, Robert; Leonhardt, Darrin; Murphy, Donald; Walton, Scott; Blackwell, David; Fernsler, Richard; Lampe, Martin; Manheimer, Wallace

    2001-10-01

    NRL's Large Area Plasma Processing System (LAPPS) utilizes a 5-10 mA/cm^2, 2-4 kV, 1 cm x 30-60 cm cross section beam of electrons guided by a magnetic field to ionize a low density (10-100 mTorr) gas.[1] Beam ionization allows large area, high density, low temperature plasmas to be generated in an arbitrary gas mixture at a well defined location. Energy and composition of particle fluxes to surfaces on both sides of the plasma can be controlled by gas mixture, location, rf bias, and other factors. Experiments have been performed using both pulsed and cw beams. Extensive diagnostics (Langmuir probes, mass and ion energy analyzers, optical emissions, microwave interferometry, etc.) have been fielded to measure the plasma properties and neutral particle fluxes (ions, neutrals, free radicals) with and without rf bias on nearby surfaces both with the beam on and off. Uniform, cold (Te < 1eV), dense (ne 10^13 cm-3) plasmas in molecular and atomic gases and mixtures thereof have been produced in agreement with theoretical expectations. Initial tests of LAPPS application such as ashing, etching, sputtering, and diamond growth have been performed. Program status will be presented. [1]R.A. Meger, et al, Phys. of Plasmas 8(5), p. 2558 (2001)

  17. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    PubMed

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors.

  18. Neutrons applications in cancer treatment and in specific diagnostics.

    PubMed

    Shahri, Keyhandokht Karimi; Motavalli, Laleh Rafat; Hakimabad, Hashem Miri

    2011-01-01

    The major effect of ionizing radiation in cells is to destroy the ability of cells to divide by damaging their DNA strands. Extensive researches are leading to an understanding that the characteristics of high LET radiations such as fast neutrons and low LET radiations like protons, photons and electrons are different; because of different types of their interactions with tissue. Low LET radiations mostly damage tissue by producing free radicals. Oxygen has an effect of enhancing free radical formation in cells. Indeed hypoxic cells, which exist in malignant tumors, are radio resistant under irradiation with low LET radiations. In contrast, neutron interacts with tissue primarily via nuclear interactions, so its biological effectiveness is not affected on the presence of oxygen. The required dose to kill the same number of cancerous cells by neutrons is about one third in comparison with photons. Clinical reports show that a full course of treatment with neutrons consists of 12 treatment sessions, compared to 30-40 treatments with photons or electrons. In conclusion, in this review we describe which cancers or tumors could be better treated with neutrons. We also refer to whether neutrons could be used for diagnosis.

  19. Neutrons applications in cancer treatment and in specific diagnostics.

    PubMed

    Shahri, Keyhandokht Karimi; Motavalli, Laleh Rafat; Hakimabad, Hashem Miri

    2011-01-01

    The major effect of ionizing radiation in cells is to destroy the ability of cells to divide by damaging their DNA strands. Extensive researches are leading to an understanding that the characteristics of high LET radiations such as fast neutrons and low LET radiations like protons, photons and electrons are different; because of different types of their interactions with tissue. Low LET radiations mostly damage tissue by producing free radicals. Oxygen has an effect of enhancing free radical formation in cells. Indeed hypoxic cells, which exist in malignant tumors, are radio resistant under irradiation with low LET radiations. In contrast, neutron interacts with tissue primarily via nuclear interactions, so its biological effectiveness is not affected on the presence of oxygen. The required dose to kill the same number of cancerous cells by neutrons is about one third in comparison with photons. Clinical reports show that a full course of treatment with neutrons consists of 12 treatment sessions, compared to 30-40 treatments with photons or electrons. In conclusion, in this review we describe which cancers or tumors could be better treated with neutrons. We also refer to whether neutrons could be used for diagnosis. PMID:21761010

  20. Compact neutron generator

    DOEpatents

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  1. Multipurpose applications of the accelerator-based neutron source[1pt] GENEPI2

    NASA Astrophysics Data System (ADS)

    Villa, F.; Baylac, M.; Billebaud, A.; Boge, P.; Cabanel, T.; Labussière, E.; Méplan, O.; Rey, S.

    2016-11-01

    GENEPI2 (GEnérateur de NEutrons Pulsé Intense) is an accelerator-based neutron source operating at LPSC laboratory in Grenoble (France). The neutrons are produced at 2.5MeV or 14.2MeV trough fusion reactions. GENEPI2 specifications allow performing efficiently accelerated irradiation tests of integrated circuits. This facility can also be operated to test and calibrate different types of detectors. This paper will describe the facility and its performances. Then, measurements of the neutron production will be presented as well as different types of experiments and irradiations. Finally, we describe upgrades undertaken to increase the neutron flux and optimize the facility for multiple applications.

  2. Development of high-energy neutron imaging for use in NDE applications

    SciTech Connect

    Dietrich, F; Hall, J; Logan, C; Schmid, G

    1999-06-01

    We are currently developing a high-energy (10 - 15 MeV) neutron imaging system for use in NDE applications. Our goal is to develop an imaging system capable of detecting cubic-mm-scale voids or other structural defects in heavily-shielded low-Z materials within thick sealed objects. The system will be relatively compact (suitable for use in a small laboratory) and capable of acquiring tomographic image data sets. The design of a prototype imaging detector and multi-axis staging system will be discussed and selected results from recent imaging experiments will be presented. The development of an intense, accelerator-driven neutron source suitable for use with the imaging system will also be discussed. Keywords: neutron imaging, neutron radiography, computed tomography, non-destructive inspection, neutron sources

  3. Optimization of the {sup 7}Li(p,n) proton beam energy for BNCT applications

    SciTech Connect

    Bleuel, D.L.; Donahue, R.J.

    1996-02-01

    The reaction {sup 7}Li(p,n){sup 7} Be has been proposed as an accelerator-based source of neutrons for Boron Neutron Capture Therapy (BNCT). This reaction has a large steep resonance for proton energies of about 2.3 MeV which ends at about 2.5 MeV. It has generally been accepted that one should use 2.5 MeV protons to get the highest yield of neutrons for BNCT. This paper suggests that for BNCT the optimum proton energy may be about 2.3 MeV and that a proton energy of about 2.2 MeV will provide the same useful neutron fluence outside a thinner moderator as the neutron fluence from a 2.5 MeV proton beam with a thicker moderator.

  4. Intense, brilliant micro γ-beams in nuclear physics and applications

    NASA Astrophysics Data System (ADS)

    Habs, D.; Gasilov, S.; Lang, C.; Thirolf, P. G.; Jentschel, M.; Diehl, R.; Schroer, C.; Barty, C. P. J.; Zamfir, N. V.

    2011-06-01

    900, we can obtain small spots for each of the beamlets. While focusing the beamlets to a much smaller spot size, we can bend them effectively with micro wedges to e.g. parallel beamlets. We can monochromatize these γ beamlets within the rocking curve of a common Laue crystal, using an additional angle selection by a collimator to reach a strongly reduced band width of 10-4 - 10-6. We propose the use of a further lens/wedge arrays or Bragg reflection to superimpose the beamlets to a very small total γ beam spot. Many experiments gain much from the high beam resolution and the smaller focal spot. This new γ optics requires high resolution diagnostics, where we want to optimize the focusing, using very thin target wires of a specific nuclear resonance fluorescence (NRF) isotope to monitor the focusing for the resonance energy. With such beams we can explore new nuclear physics of higher excited states with larger level densities. New phenomena, like the transition from chaotic to regular nuclear motion, weakly-bound halo states or states decaying by tunneling can be studied. The higher level density also allows to probe parity violating nuclear forces more sensitively. This γ optics improves many applications, like a more brilliant positron source, a more brilliant neutron source, higher specific activity of medical radioisotopes or NRF micro-imaging.

  5. Picosecond Neutron Yields from Ultra-Intense Laser-Target Interactions

    NASA Astrophysics Data System (ADS)

    Ellison, C. Leland; Fuchs, Julien

    2009-11-01

    High-flux neutron sources for neutron imaging and materials analysis applications have typically been provided by accelerator-based (Spallation Neutron Source) and reactor-based (High Flux Isotope Reactor) neutron sources. A novel approach is to use ultra-intense (> 10^18 W/cm^2) laser-target interactions to generate picosecond, collimated neutrons. Here we examine the feasibility of a source based on current (LULI) and upcoming laser facility capabilities. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. The parameters of the deuteron beam are well understood from laser-plasma and laser-target studies relevant to fast-ignition fusion. Expected neutron yields are presented in comparison to conventional neutron sources, previous experimental neutron yields, and within the context of neutron shielding safety requirements.

  6. Optimization of the beam shaping assembly in the D-D neutron generators-based BNCT using the response matrix method.

    PubMed

    Kasesaz, Y; Khalafi, H; Rahmani, F

    2013-12-01

    Optimization of the Beam Shaping Assembly (BSA) has been performed using the MCNP4C Monte Carlo code to shape the 2.45 MeV neutrons that are produced in the D-D neutron generator. Optimal design of the BSA has been chosen by considering in-air figures of merit (FOM) which consists of 70 cm Fluental as a moderator, 30 cm Pb as a reflector, 2mm (6)Li as a thermal neutron filter and 2mm Pb as a gamma filter. The neutron beam can be evaluated by in-phantom parameters, from which therapeutic gain can be derived. Direct evaluation of both set of FOMs (in-air and in-phantom) is very time consuming. In this paper a Response Matrix (RM) method has been suggested to reduce the computing time. This method is based on considering the neutron spectrum at the beam exit and calculating contribution of various dose components in phantom to calculate the Response Matrix. Results show good agreement between direct calculation and the RM method.

  7. Slower, colder, longer : prospects for a very cold neutron source.

    SciTech Connect

    Micklich, B. J.; Carpenter, J. M.; Intense Pulsed Neutron Source

    2007-01-01

    The motivation for our study is to establish the prospects for a neutron source providing intense pulsed beams with spectra as cold as is realistic. The scientific motivation is to serve applications in nanoscience, biology and technology.

  8. High neutronic efficiency, low current targets for accelerator-based BNCT applications

    SciTech Connect

    Powell, J.R.; Ludewig, H.; Todosow, M.

    1998-08-01

    The neutronic efficiency of target/filters for accelerator-based BNCT applications is measured by the proton current required to achieve a desirable neutron current at the treatment port (10{sup 9} n/cm{sup 2}/s). In this paper the authors describe two possible targeyt/filter concepts wihch minimize the required current. Both concepts are based on the Li-7 (p,n)Be-7 reaction. Targets that operate near the threshold energy generate neutrons that are close tothe desired energy for BNCT treatment. Thus, the filter can be extremely thin ({approximately} 5 cm iron). However, this approach has an extremely low neutron yield (n/p {approximately} 1.0({minus}6)), thus requiring a high proton current. The proposed solutino is to design a target consisting of multiple extremely thin targets (proton energy loss per target {approximately} 10 keV), and re-accelerate the protons between each target. Targets operating at ihgher proton energies ({approximately} 2.5 MeV) have a much higher yield (n/p {approximately} 1.0({minus}4)). However, at these energies the maximum neutron energy is approximately 800 keV, and thus a neutron filter is required to degrade the average neutron energy to the range of interest for BNCT (10--20 keV). A neutron filter consisting of fluorine compounds and iron has been investigated for this case. Typically a proton current of approximately 5 mA is required to generate the desired neutron current at the treatment port. The efficiency of these filter designs can be further increased by incorporating neutron reflectors that are co-axial with the neutron source. These reflectors are made of materials which have high scattering cross sections in the range 0.1--1.0 MeV.

  9. Development of a Fast Traveling-Wave Beam Chopper for National Spallation Neutron Source.

    NASA Astrophysics Data System (ADS)

    Kurennoy, Sergey S.; Jason, Andrew J.; Krawczyk, Frank L.

    1997-05-01

    High current and severe restrictions on beam losses, below 1 nA/m, in the designed linac for the NSNS require clean and fast (with the rise time from 2% to 98% less than 2.5 ns to accommodate a 402.5 MHz beam structure) beam chopping in its front end, at beam energy 2.5 MeV. The present R&D program includes both modification of the existing LANSCE coax-plate chopper to reduce parasitic coupling between adjacent plates, and development of new traveling-wave deflecting structures, in particular, based on a meander line. Using analytical methods and three-dimensional time-domain computer simulations we study transient effects in such structures to choose an optimal chopper design.

  10. Calculation of effective dose from measurements of secondary neutron spectra and scattered photon dose from dynamic MLC IMRT for 6 MV, 15 MV, and 18 MV beam energies.

    PubMed

    Howell, Rebecca M; Hertel, Nolan E; Wang, Zhonglu; Hutchinson, Jesson; Fullerton, Gary D

    2006-02-01

    Effective doses were calculated from the delivery of 6 MV, 15 MV, and 18 MV conventional and intensity-modulated radiation therapy (IMRT) prostate treatment plans. ICRP-60 tissue weighting factors were used for the calculations. Photon doses were measured in phantom for all beam energies. Neutron spectra were measured for 15 MV and 18 MV and ICRP-74 quality conversion factors used to calculate ambient dose equivalents. The ambient dose equivalents were corrected for each tissue using neutron depth dose data from the literature. The depth corrected neutron doses were then used as a measure of the neutron component of the ICRP protection quantity, organ equivalent dose. IMRT resulted in an increased photon dose to many organs. However, the IMRT treatments resulted in an overall decrease in effective dose compared to conventional radiotherapy. This decrease correlates to the ability of an intensity-modulated field to minimize dose to critical normal structures in close proximity to the treatment volume. In a comparison of the three beam energies used for the IMRT treatments, 6 MV resulted in the lowest effective dose, while 18 MV resulted in the highest effective dose. This is attributed to the large neutron contribution for 18 MV compared to no neutron contribution for 6 MV. PMID:16532941

  11. Electrostatic design and beam transport for a folded tandem electrostatic quadrupole accelerator facility for accelerator-based boron neutron capture therapy.

    PubMed

    Vento, V Thatar; Bergueiro, J; Cartelli, D; Valda, A A; Kreiner, A J

    2011-12-01

    Within the frame of an ongoing project to develop a folded Tandem-Electrostatic-Quadrupole (TESQ) accelerator facility for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT), we discuss here the electrostatic design of the machine, including the accelerator tubes with electrostatic quadrupoles and the simulations for the transport and acceleration of a high intensity beam.

  12. Evaporation Residue Yields in Reactions of Heavy Neutron-Rich Radioactive Ion Beams with 64Ni and 96Zr Targets

    SciTech Connect

    Shapira, Dan; Liang, J Felix; Gross, Carl J; Varner Jr, Robert L; Beene, James R; Stracener, Daniel W; Mueller, Paul Edward; Kolata, Jim J; Roberts, Amy; Loveland, Walter; Vinodkumar, A. M.; Prisbrey, Landon; Sprunger, Peter H; Grzywacz-Jones, Kate L; Caraley, Anne L

    2009-01-01

    As hindrance sets in for the fusion of heavier systems, the effect of large neutron excess in the colliding nuclei on their probability to fuse is still an open question. The detection of evaporation residues (ERs), however, provides indisputable evidence for the fusion (complete and incomplete) in the reaction. We therefore devised a system with which we could measure ERs using low intensity neutron-rich radioactive ion beams with an efficiency close to 100%. We report on measurements of the production of ERs in collisions of {sup 132,134}Sn, {sup 134}Te and {sup 134}Sb ion beams with medium mass, neutron-rich targets. The data taken with {sup 132,134}Sn bombarding a {sup 64}Ni target are compared to available data (ERs and fusion) taken with stable Sn isotopes. Preliminary data on the fusion of {sup 132}Sn with {sup 96}Zr target are also presented.

  13. Isomeric states observed in heavy neutron-rich nuclei populated in the fragmentation of a 208Pb beam

    NASA Astrophysics Data System (ADS)

    Steer, S. J.; Podolyák, Zs.; Pietri, S.; Górska, M.; Grawe, H.; Maier, K. H.; Regan, P. H.; Rudolph, D.; Garnsworthy, A. B.; Hoischen, R.; Gerl, J.; Wollersheim, H. J.; Becker, F.; Bednarczyk, P.; Cáceres, L.; Doornenbal, P.; Geissel, H.; Grębosz, J.; Kelic, A.; Kojouharov, I.; Kurz, N.; Montes, F.; Prokopwicz, W.; Saito, T.; Schaffner, H.; Tashenov, S.; Heinz, A.; Pfützner, M.; Kurtukian-Nieto, T.; Benzoni, G.; Jungclaus, A.; Balabanski, D. L.; Bowry, M.; Brandau, C.; Brown, A.; Bruce, A. M.; Catford, W. N.; Cullen, I. J.; Dombrádi, Zs.; Estevez, M. E.; Gelletly, W.; Ilie, G.; Jolie, J.; Jones, G. A.; Kmiecik, M.; Kondev, F. G.; Krücken, R.; Lalkovski, S.; Liu, Z.; Maj, A.; Myalski, S.; Schwertel, S.; Shizuma, T.; Walker, P. M.; Werner-Malento, E.; Wieland, O.

    2011-10-01

    Heavy neutron-rich nuclei were populated via the fragmentation of a E/A=1 GeV 20882Pb beam. Secondary fragments were separated and identified and subsequently implanted in a passive stopper. By the detection of delayed γ rays, isomeric decays associated with these nuclei have been identified. A total of 49 isomers were detected, with the majority of them observed for the first time. The newly discovered isomers are in 204,20580Hg, 201,202,204,20579Au, 197,203,20478Pt, 195,199-20377Ir, 193,197-19976Os, 19675Re, 190,19174W, and 18973Ta. Possible level schemes are constructed and the structure of the nuclei discussed. To aid the interpretation, shell-model as well as BCS calculations were performed.

  14. First Imaging Experiment of a Lithium Ion Battery by a Pulsed Neutron Beam at J-PARC/MLF/BL09

    NASA Astrophysics Data System (ADS)

    Kino, Koichi; Yonemura, Masao; Kiyanagi, Yoshiaki; Ishikawa, Yoshihisa; Parker, Joseph. Don.; Tanimori, Toru; Kamiyama, Takashi

    We obtain the transmission image of a commercial lithium ion (Li-ion) battery using a pulsed neutron beam at the beamline 09 of the Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex. The purpose of this study is to improve the performance of the Li-ion battery by nondestructive observation of its charging and discharging. The transmission images for three charge states (3.2 V, 3.7 V, and 4.2 V) reveal differences between these three states, which we attribute to electrolyte migration. The transmission spectra show Bragg edges originating from the electrodes, current collectors, and battery vessel. Although the battery as a whole has the expected relation between the charge accumulation and the quantity of lithium amounts in the positive and negative electrodes, a portion of the battery deviates from this relation, which may imply a position dependent charging in the battery.

  15. Monte Carlo simulations and benchmark measurements on the response of TE(TE) and Mg(Ar) ionization chambers in photon, electron and neutron beams

    NASA Astrophysics Data System (ADS)

    Lin, Yi-Chun; Huang, Tseng-Te; Liu, Yuan-Hao; Chen, Wei-Lin; Chen, Yen-Fu; Wu, Shu-Wei; Nievaart, Sander; Jiang, Shiang-Huei

    2015-06-01

    The paired ionization chambers (ICs) technique is commonly employed to determine neutron and photon doses in radiology or radiotherapy neutron beams, where neutron dose shows very strong dependence on the accuracy of accompanying high energy photon dose. During the dose derivation, it is an important issue to evaluate the photon and electron response functions of two commercially available ionization chambers, denoted as TE(TE) and Mg(Ar), used in our reactor based epithermal neutron beam. Nowadays, most perturbation corrections for accurate dose determination and many treatment planning systems are based on the Monte Carlo technique. We used general purposed Monte Carlo codes, MCNP5, EGSnrc, FLUKA or GEANT4 for benchmark verifications among them and carefully measured values for a precise estimation of chamber current from absorbed dose rate of cavity gas. Also, energy dependent response functions of two chambers were calculated in a parallel beam with mono-energies from 20 keV to 20 MeV photons and electrons by using the optimal simple spherical and detailed IC models. The measurements were performed in the well-defined (a) four primary M-80, M-100, M120 and M150 X-ray calibration fields, (b) primary 60Co calibration beam, (c) 6 MV and 10 MV photon, (d) 6 MeV and 18 MeV electron LINACs in hospital and (e) BNCT clinical trials neutron beam. For the TE(TE) chamber, all codes were almost identical over the whole photon energy range. In the Mg(Ar) chamber, MCNP5 showed lower response than other codes for photon energy region below 0.1 MeV and presented similar response above 0.2 MeV (agreed within 5% in the simple spherical model). With the increase of electron energy, the response difference between MCNP5 and other codes became larger in both chambers. Compared with the measured currents, MCNP5 had the difference from the measurement data within 5% for the 60Co, 6 MV, 10 MV, 6 MeV and 18 MeV LINACs beams. But for the Mg(Ar) chamber, the derivations reached 7

  16. Proton beam scattering system optimization for clinical and research applications

    SciTech Connect

    Wroe, A. J.; Schulte, R. W.; Slater, J. D.; Barnes, S.; McAuley, G.; Slater, J. M.

    2013-04-15

    Purpose: To develop and test a method for optimizing and constructing a dual scattering system in passively scattered proton therapy. Methods: A beam optics optimization algorithm was developed to optimize the thickness of the first scatterer (S1) and the profile (of both the high-Z material and Lexan) of the second scatterer (S2) to deliver a proton beam matching a given set of parameters, including field diameter, fluence, flatness, and symmetry. A new manufacturing process was also tested that allows the contoured second scattering foil to be created much more economically and quickly using Cerrobend casting. Two application-specific scattering systems were developed and tested using both experimental and Monte Carlo techniques to validate the optimization process described. Results: A scattering system was optimized and constructed to deliver large uniform irradiations of radiobiology samples at low dose rates. This system was successfully built and tested using film and ionization chambers. The system delivered a uniform radiation field of 50 cm diameter (to a dose of {+-}7% of the central axis) while the depth dose profile could be tuned to match the specifications of the particular investigator using modulator wheels and range shifters. A second scattering system for intermediate field size (4 cm < diameter < 10 cm) stereotactic radiosurgery and radiation therapy (SRS and SRT) treatments was also developed and tested using GEANT4. This system improved beam efficiency by over 70% compared with existing scattering systems while maintaining field flatness and depth dose profile. In both cases the proton range uniformity across the radiation field was maintained, further indicating the accuracy of the energy loss formalism in the optimization algorithm. Conclusions: The methods described allow for rapid prototyping of scattering foils to meet the demands of both research and clinical beam delivery applications in proton therapy.

  17. Optical neutron polarizers

    SciTech Connect

    Hayter, J.B.

    1990-01-01

    A neutron wave will be refracted by an appropriately varying potential. Optical neutron polarizers use spatially varying, spin- dependent potentials to refract neutrons of opposite spin states into different directions, so that an unpolarized beam will be split into two beams of complementary polarization by such a device. This paper will concentrate on two methods of producing spin-dependent potentials which are particularly well-suited to polarizing cold neutron beams, namely thin-film structures and field-gradient techniques. Thin-film optical devices, such as supermirror multilayer structures, are usually designed to deviate only one spin-state, so that they offer the possibility of making insertion (transmission) polarizers. Very good supermirrors may now be designed and fabricated, but it is not always straightforward to design mirror-based devices which are useful in real (divergent beam) applications, and some practical configurations will be discussed. Field-gradient devices, which are usually based on multipolar magnets, have tended to be too expensive for general use, but this may change with new developments in superconductivity. Dipolar and hexapolar configurations will be considered, with emphasis on the focusing characteristics of the latter. 21 refs., 7 figs.

  18. First in-beam γ -ray study of the level structure of neutron-rich 39S

    NASA Astrophysics Data System (ADS)

    Chapman, R.; Wang, Z. M.; Bouhelal, M.; Haas, F.; Liang, X.; Azaiez, F.; Behera, B. R.; Burns, M.; Caurier, E.; Corradi, L.; Curien, D.; Deacon, A. N.; Dombrádi, Zs.; Farnea, E.; Fioretto, E.; Gadea, A.; Hodsdon, A.; Ibrahim, F.; Jungclaus, A.; Keyes, K.; Kumar, V.; Lunardi, S.; Mǎrginean, N.; Montagnoli, G.; Napoli, D. R.; Nowacki, F.; Ollier, J.; O'Donnell, D.; Papenberg, A.; Pollarolo, G.; Salsac, M.-D.; Scarlassara, F.; Smith, J. F.; Spohr, K. M.; Stanoiu, M.; Stefanini, A. M.; Szilner, S.; Trotta, M.; Verney, D.

    2016-08-01

    The neutron-rich 39S nucleus has been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of 36S ions with a thin 208Pb target. The magnetic spectrometer, PRISMA, and the γ -ray array, CLARA, were used in the measurements. Gamma-ray transitions of the following energies were observed: 339, 398, 466, 705, 1517, 1656, and 1724 keV. Five of the observed transitions have been tentatively assigned to the decay of excited states with spins up to (11 /2- ). The results of a state-of-the-art shell-model calculation of the level scheme of 39S using the SDPF-U effective interaction are also presented. The systematic behavior of the excitation energy of the first 11 /2- states in the odd-A isotopes of sulfur and argon is discussed in relation to the excitation energy of the first excited 2+ states of the adjacent even-A isotopes. The states of 39S that have the components in their wave functions corresponding to three neutrons in the 1 f7 /2 orbital outside the N =20 core have also been discussed within the context of the 0 ℏ ω shell-model calculations presented here.

  19. Modeling and design of a new core-moderator assembly and neutron beam ports for the Penn State Breazeale Nuclear Reactor (PSBR)

    NASA Astrophysics Data System (ADS)

    Ucar, Dundar

    This study is for modeling and designing a new reactor core-moderator assembly and new neutron beam ports that aimed to expand utilization of a new beam hall of the Penn State Breazeale Reactor (PSBR). The PSBR is a part of the Radiation Science and Engineering Facility (RSEC) and is a TRIGA MARK III type research reactor with a movable core placed in a large pool and is capable to produce 1MW output. This reactor is a pool-type reactor with pulsing capability up to 2000 MW for 10-20 msec. There are seven beam ports currently installed to the reactor. The PSBR's existing core design limits the experimental capability of the facility, as only two of the seven available neutron beam ports are usable. The finalized design features an optimized result in light of the data obtained from neutronic and thermal-hydraulics analyses as well as geometrical constraints. A new core-moderator assembly was introduced to overcome the limitations of the existing PSBR design, specifically maximizing number of available neutron beam ports and mitigating the hydrogen gamma contamination of the neutron beam channeled in the beam ports. A crescent-shaped moderator is favored in the new PSBR design since it enables simultaneous use of five new neutron beam ports in the facility. Furthermore, the crescent shape sanctions a coupling of the core and moderator, which reduces the hydrogen gamma contamination significantly in the new beam ports. A coupled MURE and MCNP5 code optimization analysis was performed to calculate the optimum design parameters for the new PSBR. Thermal-hydraulics analysis of the new design was achieved using ANSYS Fluent CFD code. In the current form, the PSBR is cooled by natural convection of the pool water. The driving force for the natural circulation of the fluid is the heat generation within the fuel rods. The convective heat data was generated at the reactor's different operating powers by using TRIGSIMS, the fuel management code of the PSBR core. In the CFD

  20. Benchmarking of the FENDL-3 Neutron Cross-section Data Starter Library for Fusion Applications

    SciTech Connect

    Fischer, U.; Angelone, M.; Bohm, T.; Kondo, K.; Konno, C.; Sawan, M.; Villari, R.; Walker, B.

    2014-06-15

    This paper summarizes the benchmark analyses performed in a joint effort of ENEA (Italy), JAEA (Japan), KIT (Germany), and the University of Wisconsin (USA) on a computational ITER benchmark and a series of 14 MeV neutron benchmark experiments. The computational benchmark revealed a modest increase of the neutron flux levels in the deep penetration regions and a substantial increase of the gas production in steel components. The comparison to experimental results showed good agreement with no substantial differences between FENDL-3.0 and FENDL-2.1 for most of the responses. In general, FENDL-3 shows an improved performance for fusion neutronics applications.

  1. X-ray and neutron interrogation of air cargo for mobile applications

    NASA Astrophysics Data System (ADS)

    Van Liew, Seth

    2015-06-01

    A system for scanning break-bulk cargo for mobile applications is presented. This combines a 140 kV multi-view, multi-energy X-ray system with 2.5 MeV neutrons. The system uses dual energy X-ray radiography with neutron radiography. The X-ray and neutron systems were designed to be collocated in a mobile environment. Various materials were interrogated with the intent of distinguishing threat materials such as explosives from similar benign materials. In particular, the identification of threats and bengins with nearly identical effective atomic numbers has been demonstrated.

  2. Dense Plasma Focus as Collimated Source of D-D Fusion Neutron Beams for Irradiation Experiences and Study of Emitted Radiations

    SciTech Connect

    Milanese, M.; Niedbalski, J.; Moroso, R.; Guichon, S.; Supan, J.

    2008-04-07

    A 'table-top' 2 kJ, 250 kA plasma focus, the PACO (Plasma AutoConfinado), designed by the Dense Plasma Group of IFAS is used in its optimum regime for neutron yield for obtaining collimated pulsed neutron beams (100 ns). A simple and low-cost shielding arrangement was developed in order to fully eliminate the 2.45 MeV neutrons generated in the PACO device (10{sup 8} per shot at 31 kV, 1-2 mbar). Conventional neutron diagnostics: scintillator-photomultiplier (S-PMT), silver activation counters (SAC), etc., are used to determine the minimum width of the shielding walls. Emission of very hard electromagnetic pulses is also studied. Collimation using lead and copper plates is made to determine the localization of the very hard X-ray source. The maximum energy of the continuum photon distribution is estimated in 0,6 MeV using a system of filters.

  3. Applications of electron lenses: scraping of high-power beams, beam-beam compensation, and nonlinear optics

    SciTech Connect

    Stancari, Giulio

    2014-09-11

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complement the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles. At Fermilab, we are planning to install an electron lens in the Integrable Optics Test Accelerator (IOTA, a 40-m ring for 150-MeV electrons) as one of the proof-of-principle implementations of nonlinear integrable optics to achieve large tune spreads and more stable beams without loss of dynamic aperture.

  4. Application of Neutron Radiography to Flow Visualization in Supercritical Water

    NASA Astrophysics Data System (ADS)

    Takenaka, N.; Sugimoto, K.; Takami, S.; Sugioka, K.; Tsukada, T.; Adschiri, T.; Saito, Y.

    Supercritical water is used in various chemical reaction processes including hydrothermal synthesis of metal oxide nano-particles, oxidation, chemical conversion of biomass and plastics. Density of the super critical water is much less than that of the sub-critical water. By using neutron radiography, Peterson et al. have studied salt precipitation processes in supercritical water and the flow pattern in a reverse-flow vessel for salt precipitation, and Balasko et al. have revealed the behaviour of supercritical water in a container. The nano-particles were made by mixing the super critical flow and the sub critical water solution. In the present study, neutron radiography was applied to the flow visualization of the super and sub critical water mixture in a T-junction made of stainless steel pipes for high pressure and temperature conditions to investigate their mixing process. Still images by a CCD camera were obtained by using the neutron radiography system at B4 port in KUR.

  5. PREFACE: 13th International Workshop on Slow Positron Beam Techniques and Applications (SLOPOS13)

    NASA Astrophysics Data System (ADS)

    2014-04-01

    These proceedings originate from the 13th International Workshop on Slow Positron Beam Techniques and Applications SLOPOS13 which was held at the campus of the Technische Universität München in Garching between 15th-20th September, 2013. This event is part of a series of triennial SLOPOS conferences. In total 123 delegates from 21 countries participated in the SLOPOS13. The excellent scientific program comprised 50 talks and 58 posters presented during two poster sessions. It was very impressive to learn about novel technical developments on positron beam facilities and the wide range of their applications all over the world. The workshop reflected the large variety of positron beam experiments covering fundamental studies, e.g., for efficient production of anti-hydrogen as well as applied research on defects in bulk materials, thin films, surfaces, and interfaces. The topics comprised: . Positron transport and beam technology . Pulsed beams and positron traps . Defect profiling in bulk and layered structures . Nanostructures, porous materials, thin films . Surfaces and interfaces . Positronium formation and emission . Positron interactions with atoms and molecules . Many positrons and anti-hydrogen . Novel experimental techniques The international advisory committee of SLOPOS awarded student prizes for the best presented scientific contributions to a team of students from Finland, France, and the NEPOMUC team at TUM. The conference was overshadowed by the sudden death of Professor Klaus Schreckenbach immediately before the workshop. In commemoration of him as a spiritus rectus of the neutron induced positron source a minutes' silence was hold. We are most grateful for the hard work of the Local Organising Committee, the help of the International Advisory Committee, and all the students for their friendly and efficient support during the meeting. The workshop could not have occurred without the generous support of the Heinz Maier-Leibnitz Zentrum (MLZ), Deutsche

  6. High voltage supply for neutron tubes in well logging applications

    DOEpatents

    Humphreys, D. Russell

    1989-01-01

    A high voltage supply is provided for a neutron tube used in well logging. The "biased pulse" supply of the invention combines DC and "full pulse" techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

  7. Development of A Self Biased High Efficiency Solid-State Neutron Detector for MPACT Applications

    SciTech Connect

    Danon, Yaron; Bhat, Ishwara; Jian-Qiang Lu, James

    2013-09-03

    Neutron detection is an important aspect of materials protection, accounting, and control for transmutation (MPACT). Currently He-3 filled thermal neutron detectors are utilized in many applications; these detectors require high-voltage bias for operation, which complicates the system when multiple detectors are used. In addition, due to recent increase in homeland security activity and the nuclear renaissance, there is a shortage of He-3, and these detectors become more expensive. Instead, cheap solid-state detectors that can be mass produced like any other computer chips will be developed. The new detector does not require a bias for operation, has low gamma sensitivity, and a fast response. The detection system is based on a honeycomb-like silicon device, which is filled with B-10 as the neutron converter; while a silicon p-n diode (i.e., solar cell type device) formed on the thin silicon wall of the honeycomb structure detects the energetic charged particles emitted from the B-10 conversion layer. Such a detector has ~40% calculated thermal neutron detection efficiency with an overall detector thickness of about 200 ?m. Stacking of these devices allows over 90% thermal neutron detection efficiency. The goal of the proposed research is to develop a high-efficiency, low-noise, self-powered solid-state neutron detector system based on the promising results of the existing research program. A prototype of this solid-state neutron detector system with sufficient detector size (up to 8-inch diam., but still portable and inexpensive) and integrated with interface electronics (e.g., preamplifier) will be designed, fabricated, and tested as a coincidence counter for MPACT applications. All fabrications proposed are based on silicon-compatible processing; thus, an extremely cheap detector system could be massively produced like any other silicon chips. Such detectors will revolutionize current neutron detection systems by providing a solid-state alternative to

  8. Neutron Imaging Developments at LANSCE

    SciTech Connect

    Nelson, Ronald Owen; Hunter, James F.; Schirato, Richard C.; Vogel, Sven C.; Swift, Alicia L.; Ickes, Timothy Lee; Ward, William Carl; Losko, Adrian Simon; Tremsin, Anton; Sevanto, Sanna Annika; Espy, Michelle A.; Dickman, Lee Thoresen; Malone, Michael

    2015-10-29

    Thermal, epithermal, and high-energy neutrons are available from two spallation sources at the 800 MeV proton accelerator. Improvements in detectors and computing have enabled new capabilities that use the pulsed beam properties at LANSCE; these include amorphous Si (aSi) detectors, intensified charge-coupled device cameras, and micro-channel plates. Applications include water flow in living specimens, inclusions and fission products in uranium oxide, and high-energy neutron imaging using an aSi flat panel with ZnS(Ag) scintillator screen. images of a metal/plastic cylinder from photons, low-energy and high-energy neutrons are compared.

  9. Indium phosphide solar cells for laser power beaming applications

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Landis, Geoffrey A.

    1992-01-01

    Lasers can be used to transmit power to photovoltaic cells. Solar cell efficiencies are enhanced significantly under monochromatic light, and therefore a laser beam of proper wavelength could be a very effective source of illumination for a solar array operating at very high efficiencies. This work reviews the modeling studies made on indium phosphide solar cells for such an application. These cells are known to be very radiation resistant and have a potential for high efficiency. Effects of cell series resistance, laser intensity, and temperature on cell performance have been discussed.

  10. Ion beam applications research. A summary of Lewis Research Center Programs

    NASA Technical Reports Server (NTRS)

    Banks, B. A.

    1981-01-01

    A summary of the ion beam applications research (IBAR) program organized to enable the development of materials, products, and processes through the nonpropulsive application of ion thruster technology is given. Specific application efforts utilizing ion beam sputter etching, deposition, and texturing are discussed as well as ion source and component technology applications.

  11. Medical applications of in vivo neutron inelastic scattering and neutron activation analysis: Technical similarities to detection of explosives and contraband

    NASA Astrophysics Data System (ADS)

    Kehayias, J. J.

    2001-07-01

    Nutritional status of patients can be evaluated by monitoring changes in elemental body composition. Fast neutron activation (for N and P) and neutron inelastic scattering (for C and O) are used in vivo to assess elements characteristic of specific body compartments. There are similarities between the body composition techniques and the detection of hidden explosives and narcotics. All samples have to be examined in depth and the ratio of elements provides a "signature" of the chemical of interest. The N/H and C/O ratios measure protein and fat content in the body. Similarly, a high C/O ratio is characteristic of narcotics and a low C/O together with a strong presence of N is a signature of some explosives. The available time for medical applications is about 20 min—compared to a few seconds for the detection of explosives—but the permitted radiation exposure is limited. In vivo neutron analysis is used to measure H, O, C, N, P, Na, Cl, and Ca for the study of the mechanisms of lean tissue depletion with aging and wasting diseases, and to investigate methods of preserving function and quality of life in the elderly.

  12. Neutron sources: Present practice and future potential

    SciTech Connect

    Cierjacks, S.; Smith, A.B.

    1988-01-01

    The present capability and future potential of accelerator-based monoenergetic and white neutron sources are outlined in the context of fundamental and applied neutron-nuclear research. The neutron energy range extends from thermal to 500 MeV, and the time domain from steady-state to pico-second pulsed sources. Accelerator technology is summarized, including the production of intense light-ion, heavy-ion and electron beams. Target capabilities are discussed with attention to neutron-producing efficiency and power-handling capabilities. The status of underlying neutron-producing reactions is summarized. The present and future use of neutron sources in: fundamental neutron-nuclear research, nuclear data acquisition, materials damage studies, engineering tests, and biomedical applications are discussed. Emphasis is given to current status, near-term advances well within current technology, and to long-range projections. 90 refs., 4 figs.

  13. Neutron sources: present practice and future potential

    SciTech Connect

    Cierjacks, S.; Smith, A.B.

    1988-01-01

    The present capability and future potential of accelerator-based monoenergetic and white neutron sources are outlined in the context of fundamental and applied neutron-nuclear research. The neutron energy range extends from thermal to 500+ MeV, and the time domain from steady-state to pico-second pulsed sources. Accelerator technology is summarized, including the production of intense light-ion, heavy-ion and electron beams. Target capabilities are discussed with attention to neutron-production efficiency and power-handling capabilities. The status of underlying neutron-producing reactions is summarized. The present and future use of neutron sources in: (i) fundamental neutron-nuclear research, (ii) nuclear-data acquisition, (iii) materials-damage studies, (iv) engineering test, and (v) biomedical applications are discussed. Emphasis is given to current status, near-term advances well within current technology, and to long-range projections.

  14. Development of neutron/gamma generators and a polymer semiconductor detector for homeland security applications

    NASA Astrophysics Data System (ADS)

    King, Michael Joseph

    Instrumentation development is essential to the advancement and success of homeland security systems. Active interrogation techniques that scan luggage and cargo containers for shielded special nuclear materials or explosives hold great potential in halting further terrorist attacks. The development of more economical, compact and efficient source and radiation detection devices will facilitate scanning of all containers and luggage while maintaining high-throughput and low-false alarms Innovative ion sources were developed for two novel, specialized neutron generating devices and initial generator tests were performed. In addition, a low-energy acceleration gamma generator was developed and its performance characterized. Finally, an organic semiconductor was investigated for direct fast neutron detection. A main part of the thesis work was the development of ion sources, crucial components of the neutron/gamma generator development. The use of an externally-driven radio-frequency antenna allows the ion source to generate high beam currents with high, mono-atomic species fractions while maintaining low operating pressures, advantageous parameters for neutron generators. A dual "S" shaped induction antenna was developed to satisfy the high current and large extraction area requirements of the high-intensity neutron generator. The dual antenna arrangement generated a suitable current density of 28 mA/cm2 at practical RF power levels. The stringent requirements of the Pulsed Fast Neutron Transmission Spectroscopy neutron generator necessitated the development of a specialized ten window ion source of toroidal shape with a narrow neutron production target at its center. An innovative ten antenna arrangement with parallel capacitors was developed for driving the multi-antenna arrangement and uniform coupling of RF power to all ten antennas was achieved. To address the desire for low-impact, low-radiation dose active interrogation systems, research was performed on mono

  15. Los Alamos Neutron Science Center Area-A beam window heat transfer alalysis

    SciTech Connect

    Poston, D.

    1997-07-01

    Several analyses that investigate heat transfer in the Area-A beam window were conducted. It was found that the Area-A window should be able to withstand the 1-mA, 3-cm beam of the accelerator production of tritium materials test, but that the margins to failure are small. It was also determined that when the window is subjected to the 1-mA, 3-cm beam, the inner window thermocouples should read higher than the current temperature limit of 900{degrees}C, although it is possible that the thermocouples may fail before they reach these temperatures. Another finding of this study was that the actual beam width before April 1997 was 20 to 25% greater than the harp-wire printout indicated. Finally, the effect of a copper-oxide layer on the window coolant passage was studied. The results did not indicate the presence of a large copper-oxide layer; however, the results were not conclusive.

  16. Active Neutron and Gamma-Ray Instrumentation for In Situ Planetary Science Applications

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, A.; Lim, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

    2011-01-01

    We describe the development of an instrument capable of detailed in situ bulk geochemical analysis of the surface of planets, moons, asteroids, and comets. This instrument technology uses a pulsed neutron generator to excite the solid materials of a planet and measures the resulting neutron and gamma-ray emission with its detector system. These time-resolved neutron and gamma-ray data provide detailed information about the bulk elemental composition, chemical context, and density distribution of the soil within 50 cm of the surface. While active neutron scattering and neutron-induced gamma-ray techniques have been used extensively for terrestrial nuclear well logging applications, our goal is to apply these techniques to surface instruments for use on any solid solar system body. As described, experiments at NASA Goddard Space Flight Center use a prototype neutron-induced gamma-ray instrument and the resulting data presented show the promise of this technique for becoming a versatile, robust, workhorse technology for planetary science, and exploration of any of the solid bodies in the solar system. The detection of neutrons at the surface also provides useful information about the material. This paper focuses on the data provided by the gamma-ray detector.

  17. Neutron energy and time-of-flight spectra behind the lateral shield of a high energy electron accelerator beam dump. Part II: Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Roesler, S.; Liu, J. C.; Rokni, S. H.; Taniguchi, S.

    2003-05-01

    Energy spectra of high-energy neutrons and neutron time-of-flight spectra were calculated for the setup of experiment T-454 performed with a NE213 liquid scintillator at the Final Focus Test Beam (FFTB) facility at the Stanford Linear Accelerator Center. The neutrons were created by the interaction a 28.7 GeV electron beam in the aluminum beam dump of the FFTB which is housed inside a thick steel and concrete shielding. In order to determine the attenuation length of high-energy neutrons additional concrete shielding of various thicknesses was placed outside the existing shielding. The calculations were performed using the FLUKA interaction and transport code. The energy and time-of-flight spectra were recorded for the location of the detector allowing a detailed comparison with the experimental data. A generally good description of the data is achieved adding confidence to the use of FLUKA for the design of shielding for high-energy electron accelerators.

  18. Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

    NASA Astrophysics Data System (ADS)

    Rasmussen, N. G.; Simeoni, G. G.; Lefmann, K.

    2016-04-01

    A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (adjustable supermirror curvature) and the compact size (only 0.5 m long). We have simulated the neutron transport across the entire guide system. We present a detailed computer characterization of the existing device, along with the study of the factors mostly influencing the future improvement. We have optimized the simulated prototype as a function of the neutron wavelength, accounting also for all relevant features of a real instrument like the non-reflecting side edges. The results confirm the "chromatic" displacement of the focal point (flux density maximum) at fixed supermirror curvature, and the ability of a variable curvature to keep the focal point at the sample position. Our simulations are in excellent agreement with theoretical predictions and the experimentally measured beam profile. With respect to the possibility of a further upgrade, we find that supermirror coatings with m-values higher than 3.5 would have only marginal influence on the optimal behaviour, whereas comparable spectrometers could take advantage of longer focusing segments, with particular impact for the thermal region of the neutron spectrum.

  19. Application of very low energy neutron radiography with energy selection system using 4Qc(4m) supermirror

    NASA Astrophysics Data System (ADS)

    Kawabata, Yuji; Hino, Masahiro; Nakano, Takafumi; Sunohara, Hiroaki; Matsushima, Uzuki; Geltenbort, Peter

    2005-04-01

    A high contrast neutron CT system is installed in the VCN/PF2 port of Institut Laue-Langevin and VCN port of Kyoto University Reactor (KUR). A converter+C-CCD system is used for the image detection. This system has an option of the energy selection system by neutron reflection on a 4Qc (4m) supermirror. The critical angle of the neutron reflection on this mirror is four times larger than that of natural nickel and the diameter is 20 cm. As the neutron reflection on a mirror removes faster neutrons, it can be used as a low pass filter of the neutron energy. The upper limit of the reflected neutron energy can be easily changed by the rotation of the mirror. As the application of this high contrast imaging system, the density nonuniformity of an aluminum welding sample can be shown by the refraction effect of very cold neutrons in VCN/PF2/ILL.

  20. Electron Beam Irradiated Intercalated CNT Yarns For Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Waters, Deborah L.; Gaier, James R.; Williams, Tiffany S.; Lopez Calero, Johnny E.; Ramirez, Christopher; Meador, Michael A.

    2015-01-01

    Multi-walled CNT yarns have been experimentally and commercially created to yield lightweight, high conductivity fibers with good tensile properties for application as electrical wiring and multifunctional tendons. Multifunctional tendons are needed as the cable structures in tensegrity robots for use in planetary exploration. These lightweight robust tendons can provide mechanical strength for movement of the robot in addition to power distribution and data transmission. In aerospace vehicles, such as Orion, electrical wiring and harnessing mass can approach half of the avionics mass. Use of CNT yarns as electrical power and data cables could reduce mass of the wiring by thirty to seventy percent. These fibers have been intercalated with mixed halogens to increase their specific electrical conductivity to that near copper. This conductivity, combined with the superior strength and fatigue resistance makes it an attractive alternative to copper for wiring and multifunctional tendon applications. Electron beam irradiation has been shown to increase mechanical strength in pristine CNT fibers through increased cross-linking. Both pristine and intercalated CNT yarns have been irradiated using a 5-megavolt electron beam for various durations and the conductivities and tensile properties will be discussed. Structural information obtained using a field emission scanning electron microscope, energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy will correlate microstructural details with bulk properties.

  1. The influence of neutron contamination on dosimetry in external photon beam radiotherapy

    SciTech Connect

    Horst, Felix Czarnecki, Damian; Zink, Klemens

    2015-11-15

    Purpose: Photon fields with energies above ∼7 MeV are contaminated by neutrons due to photonuclear reactions. Their influence on dosimetry—although considered to be very low—is widely unexplored. Methods: In this work, Monte Carlo based investigations into this issue performed with FLUKA and EGSNRC are presented. A typical Linac head in 18 MV-X mode was modeled equivalently within both codes. EGSNRC was used for the photon and FLUKA for the neutron production and transport simulation. Water depth dose profiles and the response of different detectors (Farmer chamber, TLD-100, TLD-600H, and TLD-700H chip) in five representative depths were simulated and the neutrons’ impact (neutron absorbed dose relative to photon absorbed dose) was calculated. To take account of the neutrons’ influence, a theoretically required correction factor was defined and calculated for five representative water depths. Results: The neutrons’ impact on the absorbed dose to water was found to be below 0.1% for all depths and their impact on the response of the Farmer chamber and the TLD-700H chip was found to be even less. For the TLD-100 and the TLD-600H chip it was found to be up to 0.3% and 0.7%, respectively. The theoretical correction factors to be applied to absorbed dose to water values measured with these four detectors in a depth different from the reference/calibration depth were calculated and found to be below 0.05% for the Farmer chamber and the TLD-700H chip, but up to 0.15% and 0.35% for the TLD-100 and TLD-600H chips, respectively. In thermoluminescence dosimetry the neutrons’ influence (and therefore the additional inaccuracy in measurement) was found to be higher for TLD materials whose {sup 6}Li fraction is high, such as TLD-100 and TLD-600H, resulting from the thermal neutron capture reaction on {sup 6}Li. Conclusions: The impact of photoneutrons on the absorbed dose to water and on the response of a typical ionization chamber as well as three different types

  2. Neutron therapy of cancer

    NASA Technical Reports Server (NTRS)

    Frigerio, N. A.; Nellans, H. N.; Shaw, M. J.

    1969-01-01

    Reports relate applications of neutrons to the problem of cancer therapy. The biochemical and biophysical aspects of fast-neutron therapy, neutron-capture and neutron-conversion therapy with intermediate-range neutrons are presented. Also included is a computer program for neutron-gamma radiobiology.

  3. Trends for Electron Beam Accelerator Applications in Industry

    NASA Astrophysics Data System (ADS)

    Machi, Sueo

    2011-02-01

    Electron beam (EB) accelerators are major pieces of industrial equipment used for many commercial radiation processing applications. The industrial use of EB accelerators has a history of more than 50 years and is still growing in terms of both its economic scale and new applications. Major applications involve the modification of polymeric materials to create value-added products, such as heat-resistant wires, heat-shrinkable sheets, automobile tires, foamed plastics, battery separators and hydrogel wound dressing. The surface curing of coatings and printing inks is a growing application for low energy electron accelerators, resulting in an environmentally friendly and an energy-saving process. Recently there has been the acceptance of the use of EB accelerators in lieu of the radioactive isotope cobalt-60 as a source for sterilizing disposable medical products. Environmental protection by the use of EB accelerators is a new and important field of application. A commercial plant for the cleaning flue gases from a coal-burning power plant is in operation in Poland, employing high power EB accelerators. In Korea, a commercial plant uses EB to clean waste water from a dye factory.

  4. Neutrons, X rays, and gamma rays: Imaging detectors, material characterization techniques, and applications; Proceedings of the Meeting, San Diego, CA, July 21, 22, 1992

    NASA Astrophysics Data System (ADS)

    Carpenter, John M.; Cline, David B.; Lanza, Richard; Mildner, David F. R.

    1993-02-01

    Topics addressed include scintillating fiber technology and applications; materials characterization techniques using gamma-rays, X-rays, and neutrons; survey of principles; systems in operation; new detection systems; and applications and sources of neutrons. Also discussed are a directional fast neutron detector using scintillating fibers and electrooptics; a dark-matter detector, a novel light counter, and the ICARUS project; the major problems of MeV and GeV gamma-ray astrophysics; a compact, tunable source of monochromatic highly-directional X-rays; recent advances in neutron tomography; tailoring neutron spectra for fast neutron spectroscopy; area detectors for neutron protein crystallography; features of microstrip proportional counters; thermal neutron imaging using microchannel plates; an image plate neutron detector; a characterization of an accelerator neutron source based on the Be(d,n) reaction; and tailoring neutron spectra for fast neutron spectroscopy. (No individual items are abstracted in this volume)

  5. Application of active and passive neutron non destructive assay methods to concrete radioactive waste drums

    NASA Astrophysics Data System (ADS)

    Jallu, F.; Passard, C.; Brackx, E.

    2011-09-01

    This paper deals with the application of non-destructive neutron measurement methods to control and characterize 200 l radioactive waste drums filled with a concrete matrix. Due to its composition, and particularly to hydrogen, concrete penalizes the use of such methods to quantify uranium (U) and plutonium (Pu) components, which are mainly responsible of the α-activity of the waste. The determination of the alpha activity is the main objective of neutron measurements, in view to verify acceptance criteria in surface storage. Calibration experiments of the Active Neutron Interrogation (ANI) method lead to Detection Limit Masses (DLM) of about 1 mg of 239Pu eff in the total counting mode, and of about 10 mg of 239Pu eff in the coincidence counting mode, in case of a homogeneous Pu source and measurement times between one and two hours. Monte Carlo calculation results show a very satisfactory agreement between experimental values and calculated ones. Results of the application of passive and active neutron methods to control two real drums are presented in the last part of the paper. They show a good agreement between measured data and values declared by the waste producers. The main difficulties that had to be overcome are the low neutron signal in passive and active coincidence counting modes due to concrete, the analysis of the passive neutron signal in presence of 244Cm in the drum, which is a strong spontaneous fission neutron emitter, the variation of the active background with the concrete composition, and the analysis of the active prompt neutron signal due to the simultaneous presence of U and Pu in the drums.

  6. Thin-film deposition and characterization for neutron detection applications

    NASA Astrophysics Data System (ADS)

    Misiano, C.; Trucchi, D. M.; Renzelli, M.; Bemporad, E.; Santoni, A.; Pietropaolo, A.; Vannozzi, A.; Celentano, G.

    2015-10-01

    Solid state physics experimental techniques and characterization tools can provide a valuable contribution to the research and development activity on He-free neutron detection systems, for both detector assessment and performance improvement. Presently, a He replacement strategy relies on the use of 6Li - and/or 10B -based neutron-to-charged particle converters coupled to radiation detectors (solid state, gaseous and scintillators). These topics have been discussed during a devoted session within the HeRe (He- Replacement) in Italy Workshop held in Frascati at the ENEA Research Centre, and this paper aims at presenting a brief overview on possible deposition and characterization techniques of thin films that have been subject of discussion.

  7. NEUTRON SOURCE

    DOEpatents

    Bernander, N.K. et al.

    1960-10-18

    An apparatus is described for producing neutrons through target bombardment with deuterons. Deuterium gas is ionized by electron bombardment and the deuteron ions are accelerated through a magnetic field to collimate them into a continuous high intensity beam. The ion beam is directed against a deuteron pervious metal target of substantially the same nnaterial throughout to embed the deuterous therein and react them to produce neutrons. A large quantity of neutrons is produced in this manner due to the increased energy and quantity of ions bombarding the target.

  8. Diagnostic Application of Absolute Neutron Activation Analysis in Hematology

    SciTech Connect

    Zamboni, C.B.; Oliveira, L.C.; Dalaqua, L. Jr.

    2004-10-03

    The Absolute Neutron Activation Analysis (ANAA) technique was used to determine element concentrations of Cl and Na in blood of healthy group (male and female blood donators), select from Blood Banks at Sao Paulo city, to provide information which can help in diagnosis of patients. This study permitted to perform a discussion about the advantages and limitations of using this nuclear methodology in hematological examinations.

  9. Application of Monte Carlo codes to neutron dosimetry

    SciTech Connect

    Prevo, C.T.

    1982-06-15

    In neutron dosimetry, calculations enable one to predict the response of a proposed dosimeter before effort is expended to design and fabricate the neutron instrument or dosimeter. The nature of these calculations requires the use of computer programs that implement mathematical models representing the transport of radiation through attenuating media. Numerical, and in some cases analytical, solutions of these models can be obtained by one of several calculational techniques. All of these techniques are either approximate solutions to the well-known Boltzmann equation or are based on kernels obtained from solutions to the equation. The Boltzmann equation is a precise mathematical description of neutron behavior in terms of position, energy, direction, and time. The solution of the transport equation represents the average value of the particle flux density. Integral forms of the transport equation are generally regarded as the formal basis for the Monte Carlo method, the results of which can in principle be made to approach the exact solution. This paper focuses on the Monte Carlo technique.

  10. Fostering applications of neutron scattering techniques in developing countries: IAEA's role

    NASA Astrophysics Data System (ADS)

    Paranjpe, Shriniwas K.; Mank, G.; Ramamoorthy, N.

    2006-11-01

    Over the last 60 years research reactors have played an important role in technological and socio-economical development of mankind. Neutron scattering has been the workhorse for research and development in materials science. Developing countries with moderate flux research reactors have also been involved in using this technique. The reactors and the facilities around them have a large potential for applications, while their under-utilization has been a concern for many member states. The International Atomic Energy Agency (IAEA) has been supporting its member states in the enhancement of utilization of their research reactors. Technical meetings focussing on the area of current interests with potential applications are organized under the project on “effective utilization of research reactors,” e.g. on residual stress measurement, neutron reflectometry. Coordinated research projects (CRPs) bring together scientists from developed and developing countries, build collaborations, and exchange expertise and technology. The CRPs on research reactor utilization include topics like development of small-angle neutron scattering applications and development of sources and imaging systems for neutron radiography. New CRPs on the measurement of residual stress and accelerator-driven neutron sources will be initiated soon. The results from these meetings of CRPs are published as technical documents of the IAEA that would act as guidelines for capacity building for research reactor managers. This paper will present some of the salient features of IAEA activities in promoting research reactor utilization.

  11. Maximum proton kinetic energy and patient-generated neutron fluence considerations in proton beam arc delivery radiation therapy.

    PubMed

    Sengbusch, E; Pérez-Andújar, A; DeLuca, P M; Mackie, T R

    2009-02-01

    proton kinetic energy from 250 to 200 MeV decreases the total neutron energy fluence produced by stopping a monoenergetic pencil beam in a water phantom by a factor of 2.3. It is possible to significantly lower the requirements on the maximum kinetic energy of a compact proton accelerator if the ability to treat a small percentage of patients with rotational therapy is sacrificed. This decrease in maximum kinetic energy, along with the corresponding decrease in neutron production, could lower the cost and ease the engineering constraints on a compact proton accelerator treatment facility.

  12. Maximum proton kinetic energy and patient-generated neutron fluence considerations in proton beam arc delivery radiation therapy

    SciTech Connect

    Sengbusch, E.; Perez-Andujar, A.; DeLuca, P. M. Jr.; Mackie, T. R.

    2009-02-15

    proton kinetic energy from 250 to 200 MeV decreases the total neutron energy fluence produced by stopping a monoenergetic pencil beam in a water phantom by a factor of 2.3. It is possible to significantly lower the requirements on the maximum kinetic energy of a compact proton accelerator if the ability to treat a small percentage of patients with rotational therapy is sacrificed. This decrease in maximum kinetic energy, along with the corresponding decrease in neutron production, could lower the cost and ease the engineering constraints on a compact proton accelerator treatment facility.

  13. Maximum proton kinetic energy and patient-generated neutron fluence considerations in proton beam arc delivery radiation therapy

    PubMed Central

    Sengbusch, E.; Pérez-Andújar, A.; DeLuca, P. M.; Mackie, T. R.

    2009-01-01

    energy from 250 to 200 MeV decreases the total neutron energy fluence produced by stopping a monoenergetic pencil beam in a water phantom by a factor of 2.3. It is possible to significantly lower the requirements on the maximum kinetic energy of a compact proton accelerator if the ability to treat a small percentage of patients with rotational therapy is sacrificed. This decrease in maximum kinetic energy, along with the corresponding decrease in neutron production, could lower the cost and ease the engineering constraints on a compact proton accelerator treatment facility. PMID:19291975

  14. Development of mobile electron beam plant for environmental applications

    NASA Astrophysics Data System (ADS)

    Han, Bumsoo; Kim, Jinkyu; Kang, Wongu; Choi, Jang Seung; Jeong, Kwang-Young

    2016-07-01

    Due to the necessity of pilot scale test facility for continuous treatment of wastewater and gases on site, a mobile electron beam irradiation system mounted on a trailer has developed. This mobile electron beam irradiation system is designed for the individual field application with self-shielded structure of steel plate and lead block which will satisfy the required safety figures of International Commission on Radiological Protection (ICRP). Shielding of a mobile electron accelerator of 0.7 MeV, 30 mA has been designed and examined by Monte Carlo technique. Based on a 3-D model of electron accelerator shielding which is designed with steel and lead shield, radiation leakage was examined using the Monte Carlo N-Particle Transport (MCNP) Code. Simulations with two different versions (version 4c2 and version 5) of MCNP code showed agreements within statistical uncertainties, and the highest leakage expected is 5.5061×10-01 (1±0.0454) μSv/h, which is far below the tolerable radiation dose limit for occupational workers. This unit could treat up to 500 m3 of liquid waste per day at 2 kGy or 10,000 N m3 of gases per hour at 15 kGy.

  15. Investigation and application of neutron damage to bipolar transistors in light water reactor dosimetry

    SciTech Connect

    Roknizadeh, M.

    1987-01-01

    A method of fast neutron metrology and a basis for prediction of changes in performance parameters of semiconductor devices in power plant radiation environments has been established using Cf-252 sources. Three general purpose NPN bipolar transistors (PN2222A, ECG-196, and ECG-184) were chosen as the neutron damage monitors and the change in inverse d.c. current gain before and after irradiation was chosen as the damage parameter for the measurement. The main findings of the investigation were as follows: the change in inverse d.c. current gain for PN2222A transistors was approximately a linear function of the neutron fluence up to 2.0E15 n(1MeV)/cm/sup 2/. The concept of 1-MeV equivalent neutron fluence which characterizes an incident energy-fluence spectrum in terms of the fluence of monoenergetic neutrons at 1 MeV, is in error for application to common transistors in a typical power plant environment. Finally, the normalized damage coefficient which is the ratio of damage to 1-MeV equivalent neutron fluence divided by the measured base transit time of individual transistors, for all three types of transistors is nearly the same with an average value of 1.27E - 7 +/- 15.0% cm/sup 2//m(1 MeV).Sec.

  16. Warhead verification as inverse problem: Applications of neutron spectrum unfolding from organic-scintillator measurements

    NASA Astrophysics Data System (ADS)

    Lawrence, Chris C.; Febbraro, Michael; Flaska, Marek; Pozzi, Sara A.; Becchetti, F. D.

    2016-08-01

    Verification of future warhead-dismantlement treaties will require detection of certain warhead attributes without the disclosure of sensitive design information, and this presents an unusual measurement challenge. Neutron spectroscopy—commonly eschewed as an ill-posed inverse problem—may hold special advantages for warhead verification by virtue of its insensitivity to certain neutron-source parameters like plutonium isotopics. In this article, we investigate the usefulness of unfolded neutron spectra obtained from organic-scintillator data for verifying a particular treaty-relevant warhead attribute: the presence of high-explosive and neutron-reflecting materials. Toward this end, several improvements on current unfolding capabilities are demonstrated: deuterated detectors are shown to have superior response-matrix condition to that of standard hydrogen-base scintintillators; a novel data-discretization scheme is proposed which removes important detector nonlinearities; and a technique is described for re-parameterizing the unfolding problem in order to constrain the parameter space of solutions sought, sidestepping the inverse problem altogether. These improvements are demonstrated with trial measurements and verified using accelerator-based time-of-flight calculation of reference spectra. Then, a demonstration is presented in which the elemental compositions of low-Z neutron-attenuating materials are estimated to within 10%. These techniques could have direct application in verifying the presence of high-explosive materials in a neutron-emitting test item, as well as other for treaty verification challenges.

  17. Application of an ultraminiature thermal neutron monitor for irradiation field study of accelerator-based neutron capture therapy

    PubMed Central

    Ishikawa, Masayori; Tanaka, Kenichi; Endo, Satrou; Hoshi, Masaharu

    2015-01-01

    Phantom experiments to evaluate thermal neutron flux distribution were performed using the Scintillator with Optical Fiber (SOF) detector, which was developed as a thermal neutron monitor during boron neutron capture therapy (BNCT) irradiation. Compared with the gold wire activation method and Monte Carlo N-particle (MCNP) calculations, it was confirmed that the SOF detector is capable of measuring thermal neutron flux as low as 105 n/cm2/s with sufficient accuracy. The SOF detector will be useful for phantom experiments with BNCT neutron fields from low-current accelerator-based neutron sources. PMID:25589504

  18. Application of an ultraminiature thermal neutron monitor for irradiation field study of accelerator-based neutron capture therapy.

    PubMed

    Ishikawa, Masayori; Tanaka, Kenichi; Endo, Satrou; Hoshi, Masaharu

    2015-03-01

    Phantom experiments to evaluate thermal neutron flux distribution were performed using the Scintillator with Optical Fiber (SOF) detector, which was developed as a thermal neutron monitor during boron neutron capture therapy (BNCT) irradiation. Compared with the gold wire activation method and Monte Carlo N-particle (MCNP) calculations, it was confirmed that the SOF detector is capable of measuring thermal neutron flux as low as 10(5) n/cm(2)/s with sufficient accuracy. The SOF detector will be useful for phantom experiments with BNCT neutron fields from low-current accelerator-based neutron sources.

  19. Measurement and simulation of the response function of time of flight enhanced diagnostics neutron spectrometer for beam ion studies at EAST tokamak

    NASA Astrophysics Data System (ADS)

    Peng, X. Y.; Chen, Z. J.; Zhang, X.; Du, T. F.; Hu, Z. M.; Ge, L. J.; Zhang, Y. M.; Sun, J. Q.; Gorini, G.; Nocente, M.; Tardocchi, M.; Hu, L. Q.; Zhong, G. Q.; Pu, N.; Lin, S. Y.; Wan, B. N.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.

    2016-11-01

    The 2.5 MeV TOFED (Time-Of-Flight Enhanced Diagnostics) neutron spectrometer with a double-ring structure has been installed at Experimental Advanced Superconducting Tokamak (EAST) to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas. This work describes the response function of the TOFED spectrometer, which is evaluated for the fully assembled instrument in its final layout. Results from Monte Carlo simulations and dedicated experiments with pulsed light sources are presented and used to determine properties of light transport from the scintillator. A GEANT4 model of the TOFED spectrometer was developed to calculate the instrument response matrix. The simulated TOFED response function was successfully benchmarked against measurements of the time-of-flight spectra for quasi-monoenergetic neutrons in the energy range of 1-4 MeV. The results are discussed in relation to the capability of TOFED to perform beam ion studies on EAST.

  20. The sciences and applications of the Electron LINAC-driven neutron source in Argentina

    NASA Astrophysics Data System (ADS)

    Granada, J. R.; Mayer, R. E.; Dawidowski, J.; Santisteban, J. R.; Cantargi, F.; Blostein, J. J.; Rodríguez Palomino, L. A.; Tartaglione, A.

    2016-06-01

    The Neutron Physics group at Centro Atómico Bariloche (CNEA, Argentina) has evolved for more than forty five years around a small 25MeV linear electron accelerator. It constitutes our compact accelerator-driven neutron source (CANS), which is dedicated to the use and development of neutronic methods to tackle problems of basic sciences and technological applications. Its historical first commitment has been the determination of the total cross sections of materials as a function of neutron energy by means of transmission experiments for thermal and sub-thermal neutrons. This also allowed testing theoretical models for the generation of scattering kernels and cross sections. Through the years, our interests moved from classic pulsed neutron diffraction, which included the development of high-precision methods for the determination of very low hydrogen content in metals, towards deep inelastic neutron scattering (DINS), a powerful tool for the determination of atomic momentum distribution in condensed matter. More recently non-intrusive techniques aimed at the scanning of large cargo containers have started to be developed with our CANS, testing the capacity and limitations to detect special nuclear material and dangerous substances. Also, the ever-present "bremsstrahlung" radiation has been recognized and tested as a useful complement to instrumental neutron activation, as it permits to detect other nuclear species through high-energy photon activation. The facility is also used for graduate and undergraduate students' experimental work within the frame of Instituto Balseiro Physics and Nuclear Engineering courses of study, and also MSc and PhD theses work.