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Sample records for neutron beam applications

  1. Micromegas neutron beam monitor neutronics.

    PubMed

    Stephan, Andrew C; Miller, Laurence F

    2005-01-01

    The Micromegas is a type of ionising radiation detector that consists of a gas chamber sandwiched between two parallel plate electrodes, with the gas chamber divided by a Frisch grid into drift and amplification gaps. Investigators have applied it to a number of different applications, such as charged particle, X-ray and neutron detection. A Micromegas device has been tested as a neutron beam monitor at CERN and is expected to be used for that purpose at the Spallation Neutron Source (SNS) under construction in Oak Ridge, TN. For the Micromegas to function effectively as neutron beam monitor, it should cause minimal disruption to the neutron beam in question. Specifically, it should scatter as few neutrons as possible and avoid neutron absorption when it does not contribute to generating useful information concerning the neutron beam. Here, we present the results of Monte Carlo calculations of the effect of different types of wall materials and detector gases on neutron beams and suggest methods for minimising disruption to the beam. PMID:16381746

  2. 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

  3. 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.

  4. Neutron-beam CT of magmatic rocks: Method development and applications

    NASA Astrophysics Data System (ADS)

    Wilding, M. C.; Shields, K. E.; Heister, L.; Simpson, J.; Gibbons, M.; Richards, W. J.; Lesher, C. E.

    2001-12-01

    A 2-megawatt TRIGA reactor, now owned and operated by UC Davis as a research facility, was especially designed and built by the USAF with a large L/D for neutron-beam radiography of aircraft parts. More recent efforts in computed tomography (CT) have established capabilities of 3-D imaging of a broad range of geological materials, including textured igneous rocks up to 10's cm in size. Neutron-beam imaging is complementary to X-ray CT, especially because of the high neutron cross-sections for many light elements that are not easily detected by X-rays. Our goal is to optimize neutron-beam CT techniques for quantitative studies of igneous textures and mineralogy. To this end, we have made improvements in both image acquisition and data processing. Specifically, we have measured the attenuation coefficient for diabase for beam-hardening corrections. We have characterized the dark charge contribution and developed new strategies for flat field corrections. We have increased our sampling density to 360 images per 180º of rotation, and now correct for beam divergence. Each of these procedures contribute to a reduction in ring artifacts and thus improve image resolution. To maximize attenuation contrast, we collect images with a Cd-filtered neutron-beam. Other energy filtering techniques are also being explored. We will show examples of this imaging technique as well as applications to gabbroic rocks of the Skaergaard intrusion which involve the quantification of compaction gradients.

  5. Neutron Imaging and Applications

    SciTech Connect

    Anderson, Ian S; McGreevy, Robert L; Bilheux, Hassina Z

    2009-04-01

    Neutron Imaging and Applications offers an introduction to the basics of neutron beam production and instrumentation in addition to the wide scope of techniques that provide unique imaging capabilities over a broad and diverse range of applications. An instructional overview of neutron sources, optics and detectors, allows readers to delve more deeply into the discussions of radiography, tomography, phase contrast imaging and prospective applications using advanced neutron holography techniques and polarized beams. A section devoted to overviews in a growing range of applications describes imaging of fuel cells and hydrogen storage devices for a robust hydrogen economy; new directions in material science and engineering; the investigation of precious artifacts of cultural heritage importance; determination of plant physiology and growth processes; imaging of biological tissues and macromolecules, and the practical elements of neutron imaging for homeland security and contraband detection. Written by key experts in the field, researchers and engineers involved with imaging technologies will find Neutron Imaging and Applications a valuable reference.

  6. Directionally positionable neutron beam

    SciTech Connect

    Bumgardner, H.M.; Dance, W.E.

    1981-11-10

    Disclosed is apparatus for forming and directionally positioning a neutron beam. The apparatus includes an enclosed housing rotatable about a first axis with a neutron source axially positionable on the axis of rotation of the enclosed housing but rotationally fixed with respect to the housing. The rotatable housing is carried by a vertically positionable arm carried on a mobile transport. A collimator is supported by the rotatable housing and projects into the housing to orientationally position its inlet window at an adjustably fixed axial and radial spacing from the neutron source so that rotation of the enclosed housing causes the inlet window to rotate about a circle which is a fixed axial distance from the neutron source and has the axis of rotation of the housing as its center.

  7. 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.

  8. 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.

  9. Neutron beam design, development, and performance for neutron capture therapy

    SciTech Connect

    Harling, O.K.; Bernard, J.A. ); Zamenhof, R.G. )

    1990-01-01

    The report presents topics presented at a workshop on neutron beams and neutron capture therapy. Topics include: neutron beam design; reactor-based neutron beams; accelerator-based neutron beams; and dosimetry and treatment planning. Individual projects are processed separately for the databases. (CBS)

  10. 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.

  11. Neutron filters for producing monoenergetic neutron beams

    SciTech Connect

    Harvey, J.A.; Hill, N.W.; Harvey, J.R.

    1982-01-01

    Neutron transmission measurements have been made on high-purity, highly-enriched samples of /sup 58/Ni (99.9%), /sup 60/Ni (99.7%), /sup 64/Zn (97.9%) and /sup 184/W (94.5%) to measure their neutron windows and to assess their potential usefulness for producing monoenergetic beams of intermediate energies from a reactor. Transmission measurements on the Los Alamos Sc filter (44.26 cm Sc and 1.0 cm Ti) have been made to determine the characteristics of the transmitted neutron beam and to measure the total cross section of Sc at the 2.0 keV minimum. When corrected for the Ti and impurities, a value of 0.35 +- 0.03 b was obtained for this minimum.

  12. 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

  13. 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

  14. 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.

  15. Production of Epithermal Neutron Beams for BNCT

    SciTech Connect

    Colangelo, P.; Colonna, N.; Santorelli, P.; Variale, V.; Paticchio, V.; Maggipinto, G.

    1999-12-31

    Boron Neutron Capture Therapy, a promising modality for the treatment of malignant tumors, relies on the use of neutron beams of suitable energy and intensity. For deep-seated tumors, simulations indicate that the optimal neutron energy is in the epithermal region, and in particular between 1 and 10 keV. Therapeutic neutron beams of high spectral purity could be produced with low-energy accelerators, through a suitable neutron producing reaction. In this talk we present an overview of some recently investigated reactions for the production of intense epithermal neutron beams for BNCT, and their potential use towards the setup of an hospital-based BNCT facility.

  16. Shaping micron-sized cold neutron beams

    NASA Astrophysics Data System (ADS)

    Ott, Frédéric; Kozhevnikov, Sergey; Thiaville, André; Torrejón, Jacob; Vázquez, Manuel

    2015-07-01

    In the field of neutron scattering, the need for micro-sized (1-50 μm) thermal or cold neutron beams has recently appeared, typically in the field of neutron imaging to probe samples with a high spatial resolution. We discuss various possibilities of producing such micro-sized neutron beams. The advantages and drawbacks of the different techniques are discussed. We show that reflective optics offers the most flexible way of producing tiny neutron beams together with an enhanced signal to background ratio. The use of such micro beams is illustrated by the study of micrometric diameter magnetic wires.

  17. 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.

  18. 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

  19. Intermediate energy neutron beams from the MURR

    SciTech Connect

    Brugger, R.M.; Herleth, W.H. )

    1990-01-01

    Several reactors in the United States are potential candidates to deli1ver beams of intermediate energy neutrons for NCT. At this time, moderators, as compared to filters, appear to be the more effective means of tailoring the flux of these reactors. The objective is to sufficiently reduce the flux of fast neutrons while producing enough intermediate energy neutrons for treatments. At the University of Missouri Research Reactor (MURR), the code MCNP has recently been used to calculate doses in a phantom. First, ideal beams of 1, 35, and 1000 eV neutrons were analyzed to determine doses and advantage depths in the phantom. Second, a high quality beam that had been designed to fit in the thermal column of the MURR, was reanalyzed. MCNP calculations of the dose in phantom in this beam confirmed previous calculations and showed that this beam would be a nearly ideal one with neutrons of the desired energy and also a high neutron current. However, installation of this beam will require a significant modification of the thermal column of the MURR. Therefore, a second beam that is less difficult to build and install, but of lower neutron current, has been designed to fit in MURR port F. This beam is designed using inexpensive A1, S, and Pb. The doses calculated in the phantom placed in this beam show that it will be satisfactory for sample tests, animal tests, and possible initial patient trials. Producing this beam will require only modest modifications of the existing tube.

  20. 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.

  1. 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.

  2. 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.

  3. Beam characterization at the Neutron Radiography Reactor

    SciTech Connect

    Sarah W. Morgan; Jeffrey C. King; Chad L. Pope

    2013-12-01

    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, potential image quality, and beam divergence, is vital for producing quality radiographic images. This paper provides a characterization of 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 potential 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. The NRAD has an effective collimation ratio greater than 125, a beam divergence of 0.3 +_ 0.1 degrees, and a gold foil cadmium ratio of 2.7. The flux profile has been quantified and the facility is an ASTM Category 1 radiographic facility. Based on bare and cadmium covered foil activation results, the neutron energy spectrum used in the current MCNP model of the radiography beamline over-samples the thermal region of the neutron energy spectrum.

  4. Neutron fan beam source for neutron radiography purpose

    SciTech Connect

    Le Tourneur, P.; Bach, P.; Dance, W. E.

    1999-06-10

    The development of the DIANE neutron radiography system included a sealed-tube neutron generator for this purpose and the optimization of the system's neutron beam quality in terms of divergence and useful thermal neutron yield for each 14-MeV neutron produced. Following this development, the concept of a DIANE fan beam source is herewith introduced. The goal which drives this design is one of economy: by simply increasing the aperture dimension of a conventional DIANE beam in one plane of its collimator axis to a small-angle, fan-shaped output, the useful beam area for neutron radiography would be substantially increased. Thus with the same source, the throughput, or number of objects under examination at any given time, would be augmented significantly. Presented here are the design of this thermal neutron source and the initial Monte Carlo calculations. Taking into account the experience with the conventional DIANE neutron radiography system, these result are discussed and the potential of and interest in such a fan-beam source are explored.

  5. 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.

  6. 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

  7. Application of adjoint Monte Carlo to accelerate simulations of mono-directional beams in treatment planning for Boron Neutron Capture Therapy

    SciTech Connect

    Nievaart, V. A.; Legrady, D.; Moss, R. L.; Kloosterman, J. L.; Hagen, T. H. J. J. van der; Dam, H. van

    2007-04-15

    This paper deals with the application of the adjoint transport theory in order to optimize Monte Carlo based radiotherapy treatment planning. The technique is applied to Boron Neutron Capture Therapy where most often mixed beams of neutrons and gammas are involved. In normal forward Monte Carlo simulations the particles start at a source and lose energy as they travel towards the region of interest, i.e., the designated point of detection. Conversely, with adjoint Monte Carlo simulations, the so-called adjoint particles start at the region of interest and gain energy as they travel towards the source where they are detected. In this respect, the particles travel backwards and the real source and real detector become the adjoint detector and adjoint source, respectively. At the adjoint detector, an adjoint function is obtained with which numerically the same result, e.g., dose or flux in the tumor, can be derived as with forward Monte Carlo. In many cases, the adjoint method is more efficient and by that is much quicker when, for example, the response in the tumor or organ at risk for many locations and orientations of the treatment beam around the patient is required. However, a problem occurs when the treatment beam is mono-directional as the probability of detecting adjoint Monte Carlo particles traversing the beam exit (detector plane in adjoint mode) in the negative direction of the incident beam is zero. This problem is addressed here and solved first with the use of next event estimators and second with the application of a Legendre expansion technique of the angular adjoint function. In the first approach, adjoint particles are tracked deterministically through a tube to a (adjoint) point detector far away from the geometric model. The adjoint particles will traverse the disk shaped entrance of this tube (the beam exit in the actual geometry) perpendicularly. This method is slow whenever many events are involved that are not contributing to the point

  8. Beam characterization at the neutron radiography reactor

    NASA Astrophysics Data System (ADS)

    Morgan, Sarah

    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 thesis 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Lyoluminescence dosimetry in photon and fast neutron beams.

    PubMed

    Puite, K J; Crebolder, D L

    1977-11-01

    The lyoluminescence (LL) technique using mannose, a monosaccharide, is described. Dose-response curves for 60Co-gamma-rays (5 rad to 120 krad), fission neutrons, 5.3 MeV and 15 MeV neutrons (100 rad to 20 krad) have been measured. The close tissue-equivalence of mannose makes this material well suited for dosimetric use in low energy X-ray fields for radiotherapy and radiobiology. It also provides a cheap, simple and reproducible dosemeter in industrial applications of radiation (sprouting inhibition of onions and potatoes; control of insect infestation). After correction for the gamma contamination of the neutron beam the LL signal per rad in ICRU muscle tissue from the neutron irradiations has been derived and the relative effectiveness of the LL signal for fast neutrons in mannose has been calculated as 0.34 +/- 0.03 (fission neutrons), 0.63 +/- 0.07 (5.3 MeV neutrons) and 0.74 +/- 0.05 (15 MeV neutrons). These results are compared with data from other systems. It is concluded that mannose can be used as a transfer system in neutron dosimetry, if its variation in sensitivity with neutron energy is taken into account. PMID:594143

  17. 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.

  18. Monochromatic neutron beam production at Brazilian nuclear research reactors

    NASA Astrophysics Data System (ADS)

    Stasiulevicius, Roberto; Rodrigues, Claudio; Parente, Carlos B. R.; Voi, Dante L.; Rogers, John D.

    2000-12-01

    Monochomatic beams of neutrons are obtained form a nuclear reactor polychromatic beam by the diffraction process, suing a single crystal energy selector. In Brazil, two nuclear research reactors, the swimming pool model IEA-R1 and the Argonaut type IEN-R1 have been used to carry out measurements with this technique. Neutron spectra have been measured using crystal spectrometers installed on the main beam lines of each reactor. The performance of conventional- artificial and natural selected crystals has been verified by the multipurpose neutron diffractometers installed at IEA-R1 and simple crystal spectrometer in operator at IEN- R1. A practical figure of merit formula was introduced to evaluate the performance and relative reflectivity of the selected planes of a single crystal. The total of 16 natural crystals were selected for use in the neutron monochromator, including a total of 24 families of planes. Twelve of these natural crystal types and respective best family of planes were measured directly with the multipurpose neutron diffractometers. The neutron spectrometer installed at IEN- R1 was used to confirm test results of the better specimens. The usually conventional-artificial crystal spacing distance range is limited to 3.4 angstrom. The interplane distance range has now been increased to approximately 10 angstrom by use of naturally occurring crystals. The neutron diffraction technique with conventional and natural crystals for energy selection and filtering can be utilized to obtain monochromatic sub and thermal neutrons with energies in the range of 0.001 to 10 eV. The thermal neutron is considered a good tool or probe for general applications in various fields, such as condensed matter, chemistry, biology, industrial applications and others.

  19. Neutron resonance averaging with filtered beams

    SciTech Connect

    Chrien, R.E.

    1985-01-01

    Neutron resonance averaging using filtered beams from a reactor source has proven to be an effective nuclear structure tool within certain limitations. These limitations are imposed by the nature of the averaging process, which produces fluctuations in radiative intensities. The fluctuations have been studied quantitatively. Resonance averaging also gives us information about initial or capture state parameters, in particular the photon strength function. Suitable modifications of the filtered beams are suggested for the enhancement of non-resonant processes.

  20. A Comparison of Neutron Beams for BNCT

    SciTech Connect

    Blue, Thomas E.; Woollard, Jeffrey E.

    2001-06-17

    The potential of the Ohio State University Research Reactor (OSURR) with a fission converter plate (FCP) for clinical boron neutron capture therapy (BNCT) is evaluated. The evaluation used design methods that were developed for the analysis of the OSU design of an accelerator-based neutron source (ABNS) for BNCT. The paper compares an FCP epithermal neutron beam, which is based on the OSURR, with the ABNS. Neutron and gamma-ray absorbed dose rates and the boron-10 specific absorbed dose rate were calculated. A major goal of the analysis was to determine if a 500-kW reactor with an FCP can produce a neutron field with sufficient intensity to allow a patient to be treated in an acceptable treatment time with adequate beam quality. The answer obtained was positive, provided that the patient is treated with at least four fractions. Although the quality of the neutron field for the FCP is slightly inferior to that of the ABNS, it was judged to be acceptable.

  1. 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.

  2. Neutron beam characterization at the Intense Pulsed Neutron Source.

    SciTech Connect

    Iverson, E. B.

    1998-05-18

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a spallation neutron source dedicated to materials research. Its three cryogenic methane moderators provide twelve neutron beams to fourteen neutron scattering instruments and test facilities. The moderators at IPNS are of cryogenic methane (CH{sub 4}); one of liquid methane at 100 K, and two of solid methane at 30 K. These moderators produce intense beams of both cold and thermal neutrons. The moderators are each of a different physical configuration in order to tailor their performance for the instruments and facilities that operate on the neutron beams. As part of the ongoing operation of IPNS, as well as new enhancements to the target, moderator, and reflector systems, we have performed experiments characterizing the energy and time distribution of neutrons in the various beams. These measurements provide absolutely normalized energy spectra using foil activation techniques joined with time-of-flight measurements, and energy-dependent time distributions using a time-focused crystal analyzer. The IPNS accelerator system delivers 14 {micro}A of 450 MeV protons, in 100 ns pulses at 30 Hz, to a target composed of water-cooled depleted uranium disks. The solid methane ''H'' moderator is 100 by 100 by 45 mm in size, centerline poisoned with 0.25 mg/mm{sup 2} gadolinium, and decoupled from the graphite reflector with 0.5 mm of cadmium. The liquid methane ''F'' moderator, which is viewed from both faces, is also 100 by 100 by 45 mm in size, gadolinium poisoned 16 mm below each of the two viewed surfaces, and decoupled from the graphite reflector with cadmium. The solid methane ''C'' moderator has a re-entrant ''grooved'' geometry. The moderator is 100 by 100 by 80 mm overall, with 40 mm deep 12 mm wide horizontal grooves in the viewed surface. These grooves cover 50% of the viewed surface area. The ''C'' moderator is unpoisoned, but is decoupled from the graphite reflector with 0.5 mm of cadmium.

  3. 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.

  4. 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.

  5. The New Uppsala Neutron Beam Facility

    SciTech Connect

    Pomp, S.; Blomgren, J.; Hildebrand, A.; Johansson, C.; Mermod, P.; Oesterlund, M.; Prokofiev, A.V.; Bystroem, O.; Ekstroem, C.; Haag, N.; Jonsson, O.; Reistad, D.; Renberg, P.-U.; Wessman, D.; Ziemann, V.; Nilsson, L.; Olsson, N.; Tippawan, U.

    2005-05-24

    A new quasi-monoenergetic neutron beam facility has been constructed at the The Svedberg Laboratory (TSL) in Uppsala, Sweden. Key features include an energy range of 20 to 175 MeV, high fluxes, and the possibility of large-area fields. Besides cross-section measurements, the new facility has been designed specifically to provide optimal conditions for testing of single-event effects in electronics and for dosimetry development. First results of the beam characterization measurements performed in early 2004 are reported.

  6. 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.

  7. 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.

  8. Monoenergetic Neutrons for Stellar Applications

    NASA Astrophysics Data System (ADS)

    Mosconi, M.; Heil, M.; Käppeler, F.; Plag, R.; Mengoni, A.; Nolte, R.

    2009-09-01

    With modern techniques, neutron-capture cross sections can be determined with uncertainties of a few percent. However, Maxwellian averaged cross sections calculated from such data require a correction (because low-lying excited states are thermally populated in the hot stellar photon bath) which has to be determined by theoretical calculations. These calculations can be improved with information from indirect measurements, in particular by the inelastic scattering cross section. For low-lying levels, the inelastically scattered neutrons are difficult to separate from the dominant elastic channel. This problem is best solved by means of pulsed, monoenergetic neutron beams. For this reason, a pulsed beam of 30 keV neutrons with an energy spread of 7 to 9 keV FWHM and a width from 10 to 15 ns has been produced at Forschungszentrum Karlsruhe using the 7Li(p, n)7Be reaction directly at the reaction threshold. With this neutron beam the inelastic scattering cross section of the first excited level at 9.75 keV in 187Os was determined with a relative uncertainty of 6%. The use of monoenergetic neutron beams has been further pursued at the Physikalisch-Technische Bundesanstalt in Braunschweig, including the 3H(p, n)3He reaction for producing neutrons with an energy of 64 keV.

  9. 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

  10. SPALLATION NEUTRON SOURCE BEAM CURRENT MONITOR ELECTRONICS.

    SciTech Connect

    KESSELMAN,M.; DAWSON,W.C.

    2002-05-06

    This paper will discuss the present electronics design for the beam current monitor system to be used throughout the Spallation Neutron Source (SNS) under construction at Oak Ridge National Laboratory. The beam is composed of a micro-pulse structure due to the 402.5MHz RF, and is chopped into mini-pulses of 645ns duration with a 300ns gap, providing a macro-pulse of 1060 mini-pulses repeating at a 60Hz rate. Ring beam current will vary from about 15ma peak during studies, to about 50Amps peak (design to 100 amps). A digital approach to droop compensation has been implemented and initial test results presented.

  11. Novel applications of fast neutron interrogation methods

    NASA Astrophysics Data System (ADS)

    Gozani, Tsahi

    1994-12-01

    The development of non-intrusive inspection methods for contraband consisting primarily of carbon, nitrogen, oxygen, and hydrogen requires the use of fast neutrons. While most elements can be sufficiently well detected by the thermal neutron capture process, some important ones, e.g., carbon and in particular oxygen, cannot be detected by this process. Fortunately, fast neutrons, with energies above the threshold for inelastic scattering, stimulate relatively strong and specific gamma ray lines from these elements. The main lines are: 6.13 for O, 4.43 for C, and 5.11, 2.31 and 1.64 MeV for N. Accelerator-generated neutrons in the energy range of 7 to 15 MeV are being considered as interrogating radiations in a variety of non-intrusive inspection systems for contraband, from explosives to drugs and from coal to smuggled, dutiable goods. In some applications, mostly for inspection of small items such as luggage, the decision process involves a rudimentary imaging, akin to emission tomography, to obtain the localized concentration of various elements. This technique is called FNA — Fast Neutron Analysis. While this approach offers improvements over the TNA (Thermal Neutron Analysis), it is not applicable to large objects such as shipping containers and trucks. For these challenging applications, a collimated beam of neutrons is rastered along the height of the moving object. In addition, the neutrons are generated in very narrow nanosecond pulses. The point of their interaction inside the object is determined by the time of flight (TOF) method, that is measuring the time elapsed from the neutron generation to the time of detection of the stimulated gamma rays. This technique, called PFNA (Pulsed Fast Neutron Analysis), thus directly provides the elemental, and by inference, the chemical composition of the material at every volume element (voxel) of the object. The various neutron-based techniques are briefly described below.

  12. 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.

  13. 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.

  14. Spallation neutron source beam loss monitor system

    NASA Astrophysics Data System (ADS)

    Gassner, D.; Witkover, R.; Cameron, P.; Power, J.

    2000-11-01

    The Spallation Neutron Source facility to be built at ORNL is designed to accumulate 2×1014 protons at 1.0 GeV and deliver them to the experimental target in one bunch at 60 Hz. To achieve this goal and protect the machine from excessive radiation activation, an uncontrolled loss criteria of 1 part in 104 (1 W/m) has been specified. Measured losses will be conditioned to provide machine tuning data, a beam abort trigger, and logging of loss history. The design of the distributed loss monitor system utilizing argon-filled glass ionization chambers and scintillator-photomultipliers will be presented.

  15. 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.

  16. Feasibility study of using laser-generated neutron beam for BNCT.

    PubMed

    Kasesaz, Y; Rahmani, F; Khalafi, H

    2015-09-01

    The feasibility of using a laser-accelerated proton beam to produce a neutron source, via (p,n) reaction, for Boron Neutron Capture Therapy (BNCT) applications has been studied by MCNPX Monte Carlo code. After optimization of the target material and its thickness, a Beam Shaping Assembly (BSA) has been designed and optimized to provide appropriate neutron beam according to the recommended criteria by International Atomic Energy Agency. It was found that the considered laser-accelerated proton beam can provide epithermal neutron flux of ∼2×10(6) n/cm(2) shot. To achieve an appropriate epithermal neutron flux for BNCT treatment, the laser must operate at repetition rates of 1 kHz, which is rather ambitious at this moment. But it can be used in some BNCT researches field such as biological research. PMID:26115204

  17. 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.

  18. Optimization of the Epithermal Neutron Beam for Boron Neutron Capture Therapy at the Brookhaven Medical Research Reactor

    SciTech Connect

    Hu, J.P.; Reciniello, R.N.; Holden, N.E.

    2004-05-01

    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 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.

  19. Search for Neutron Anti-Neutron Oscillation using Cold Neutron Beams with Focusing Optics

    NASA Astrophysics Data System (ADS)

    Shimizu, Hirohiko; NNBar Collaboration

    2014-09-01

    The electric charge of neutrons is experimentally known as less than 10-21 e and considered as exactly zero and the transition between neutron and anti-neutron is allowed in terms of the conservation of the electric charge but is considered forbidden according to the empirical conservation law of the baryon number. On the other hand, the existence of physical processes which violates the conservation of the baryon number is required in the Sakharov's conditions to explain the baryon assymmetry in the big-bang cosmology. The search for the neutron antineutron (n n) oscillation offers information the baryon number violation with the Δ (B - L) = 2 complementary to the attempts with Δ (B - L) = 0 . The sensitivity to the n n oscillation has been improved by searching for the instability of nuclei via n n oscillation in large-scale deep-underground experiments, which are now limited by the background. On the other hand, the improvement of accelerator-driven neutron sources and transport optics of slow neutron beams have introduced new possibility to improve the sensitivity to n n by orders of magnitude. In this paper, we discuss the experimental sensitivity to n n oscillation with accelerator-based neutron sources and neutron focusing optics.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Neutron beam characterization at the Neutron Radiography Reactor (NRAD)

    SciTech Connect

    Imel, G.R.; Urbatsch, T.; Pruett, D.P.; Ross, J.R.

    1990-01-01

    The Neutron Radiography Reactor (NRAD) is a 250-kW TRIGA Reactor operated by Argonne National Laboratory and is located near Idaho Falls, Idaho. The reactor and its facilities regarding radiography are detailed in another paper at this conference; this paper summarizes neutron flux measurements and calculations that have been performed to better understand and potentially improve the neutronics characteristics of the reactor.

  5. Measurements of gamma dose and thermal neutron fluence in phantoms exposed to a BNCT epithermal beam with TLD-700.

    PubMed

    Gambarini, G; Magni, D; Regazzoni, V; Borroni, M; Carrara, M; Pignoli, E; Burian, J; Marek, M; Klupak, V; Viererbl, L

    2014-10-01

    Gamma dose and thermal neutron fluence in a phantom exposed to an epithermal neutron beam for boron neutron capture therapy (BNCT) can be measured by means of a single thermoluminescence dosemeter (TLD-700). The method exploits the shape of the glow curve (GC) and requires the gamma-calibration GC (to obtain gamma dose) and the thermal-neutron-calibration GC (to obtain neutron fluence). The method is applicable for BNCT dosimetry in case of epithermal neutron beams from a reactor because, in most irradiation configurations, thermal neutrons give a not negligible contribution to the TLD-700 GC. The thermal neutron calibration is not simple, because of the impossibility of having thermal neutron fields without gamma contamination, but a calibration method is here proposed, strictly bound to the method itself of dose separation. PMID:24435913

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. The modeling of a linear multi-beam deuteron compact accelerator for neutron generation

    NASA Astrophysics Data System (ADS)

    Araujo, Wagner L.; Campos, Tarcisio P. R.

    2012-07-01

    There is a prominent interest in obtaining high-flux neutron generators due to its wide range of applications and possibilities. The beam current that reaches the target is one of the main factors for determining the performance of the generator. In the present paper we address the modeling of a deuteron compact accelerator for neutron generation underlying the electrode placement and providing an optimized multiple beam accelerator geometry. The methodology consists of electrode displacement calculations and simulations of the deuteron and neutron beam transport. A phenomenological model has been proposed based on experimental data, which provides two electrode configuration patterns. Both configurations were compared through electromagnetic simulations considering a single-beam accelerator-type. The configuration with highest ion current has led to a new geometry incorporating multiple beams. The final prototype presents an interesting beam profile achieving deuteron kinetic energy in the order of 180 keV and current up to 198 mA. Estimated yield for this generator was 1012 n/s. A shield was designed, based on Monte Carlo simulations. Dose calculation was appraised showing a neutron and photon dose rate of 7.73 and 14.50 mGy h-1 in front of 46 cm shield. The achieved design offers a suitable performance toward a compact high-flux neutron generator.

  11. 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.

  12. 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.

  13. Two-dimensional differential calibration method for a neutron dosemeter using a thermal neutron beam.

    PubMed

    Matsumoto, Tetsuro; Harano, Hideki; Masuda, Akihiko; Nishiyama, Jun; Matsue, Hideaki; Uritani, Akira; Nunomiya, Tomoya

    2013-08-01

    A new thermal neutron calibration method to experimentally determine the energy response function of a neutron detector using a pulse parallel beam and the time-of-flight (TOF) technique is developed. The calibration method was experimentally demonstrated for a (3)He proportional counter and an electric personal dosemeter using a pulsed thermal neutron beam from the research reactor JRR-3M. The responses of the detectors were successfully obtained as a function of neutron energy. However, detailed information on the detector structure is required to obtain the spatial response distribution for the detector. The authors further propose an improved calibration method obtaining the spatial response distribution using a pulsed narrow beam, the TOF technique and a beam scanning technique. PMID:23509397

  14. BEAM INSTRUMENTATION FOR THE SPALLATION NEUTRON SOURCE RING.

    SciTech Connect

    WITKOVER,R.L.; CAMERON,P.R.; SHEA,T.J.; CONNOLLY,R.C.; KESSELMAN,M.

    1999-03-29

    The Spallation Neutron Source (SNS) will be constructed by a multi-laboratory collaboration with BNL responsible for the transfer lines and ring. [1] The 1 MW beam power necessitates careful monitoring to minimize un-controlled loss. This high beam power will influence the design of the monitors in the high energy beam transport line (HEBT) from linac to ring, in the ring, and in the ring-to-target transfer line (RTBT). The ring instrumentation must cover a 3-decade range of beam intensity during accumulation. Beam loss monitoring will be especially critical since un-controlled beam loss must be kept below 10{sup -4}. A Beam-In-Gap (BIG) monitor is being designed to assure out-of-bucket beam will not be lost in the ring.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Tailoring phase-space in neutron beam extraction

    NASA Astrophysics Data System (ADS)

    Weichselbaumer, S.; Brandl, G.; Georgii, R.; Stahn, J.; Panzner, T.; Böni, P.

    2015-09-01

    In view of the trend towards smaller samples and experiments under extreme conditions it is important to deliver small and homogeneous neutron beams to the sample area. For this purpose, elliptic and/or Montel mirrors are ideally suited as the phase space of the neutrons can be defined far away from the sample. Therefore, only the useful neutrons will arrive at the sample position leading to a very low background. We demonstrate the ease of designing neutron transport systems using simple numeric tools, which are verified using Monte-Carlo simulations that allow taking into account effects of gravity and finite beam size. It is shown that a significant part of the brilliance can be transferred from the moderator to the sample. Our results may have a serious impact on the design of instruments at spallation sources such as the European Spallation Source (ESS) in Lund, Sweden.

  2. Determination of the neutron and photon spectra of a clinical fast neutron beam.

    PubMed

    Moyers, M F; Horton, J L

    1990-01-01

    A simple technique to determine the neutron and photon spectra of a clinical fast neutron beam is described. This technique involves making narrow beam attenuation measurements with a pair of ionization chambers and an iterative fitting program to analyze the data. A method is also described for determining the first-guess neutron spectrum for input into the iterative program. The results of the analysis yield spectra suitable for use in dose calculation algorithms and dosimetry protocols. Presented here is the first-known published photon spectrum from a clinical machine. PMID:2120558

  3. 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.

  4. Fast Pulsing Neutron Generators for Security Application

    SciTech Connect

    Ji, Q.; Regis, M.; Kwan, J. W.

    2009-04-24

    Active neutron interrogation has been demonstrated to be an effective method of detecting shielded fissile material. A fast fall-time/fast pulsing neutron generator is needed primarily for differential die-away technique (DDA) interrogation systems. A compact neutron generator, currently being developed in Lawrence Berkeley National Laboratory, employs an array of 0.6-mm-dia apertures (instead of one 6-mm-dia aperture) such that gating the beamlets can be done with low voltage and a small gap to achieve sub-microsecond ion beam fall time and low background neutrons. Arrays of 16 apertures (4x4) and 100 apertures (10x10) have been designed and fabricated for a beam extraction experiment. The preliminary results showed that, using a gating voltage of 1200 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is approximately 0.15 mu s at beam energies of 1000 eV.

  5. Analysis of epithermal neutron beam experiments at the HIFAR reactor

    SciTech Connect

    Harrington, B.V.; Constantine, G.

    1995-01-01

    A calculated model of the entire core of the DIDO class reactor HIFAR has been used to analyze epithermal neutron beam experiments. In the experiments, an off-center fuel element was replaced by a dummy fuel element voided by a dry liner in which an aluminium spectrum shifter was suspended at core center to extract the beam. Various combinations of the filter materials aluminum, iron, sulfur, titanium, and cadmium were inserted near the top of the dry liner, and liquid argon was placed in a cryostat above the dummy element. Reaction rates were measured in a fission chamber, sandwiched between various thicknesses of polyethylene, in order to assess the accuracy of the calculational model for different regions of the neutron energy spectrum of the beam. The neutron source distribution of the HIFAR core was obtained from a three-dimensional diffusion calculation, with burnup-dependent fuel compositions and fission products included, using the AUS modular code scheme. Argon cross sections were generated from ENDL-84 data and resonance parameters taken from Neutron Cross Sections (1984). A whole-core MCNP source calculation was used to analyze the experiments giving good agreement between measured and calculated reaction rates. This whole-core model of HIFAR may be applied with confidence to predict the performance of filtered beams for boron neutron capture therapy and also to other HIFAR calculations.

  6. 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.

  7. Evaluation of an iron-filtered epithermal neutron beam for neutron-capture therapy

    SciTech Connect

    Musolino, S.V. ); McGinley, P.H. ); Greenwood, R.C. ); Kliauga, P. ); Fairchild, R.G. )

    1991-07-01

    An epithermal neutron filter using iron, aluminum, and sulfur was evaluated to determine if the therapeutic performance could be improved with respect to aluminum--sulfur-based filters. An empirically optimized filter was developed that delivered a 93% pure beam of 24-keV epithermal neutrons. It was expected that a thick filter using iron with a density thickness {gt}200 g/cm{sup 2} would eliminate the excess gamma contamination found in Al--S filters. This research showed that prompt gamma production from neutron interactions in iron was the dominant dose component. Dosimetric parameters of the beam were determined from the measurement of absorbed dose in air, thermal neutron flux in a head phantom, neutron and gamma spectroscopy, and microdosimetry.

  8. 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}.

  9. Characteristics of the new THOR epithermal neutron beam for BNCT.

    PubMed

    Tung, C J; Wang, Y L; Hsu, F Y; Chang, S L; Liu, Y-W H

    2004-11-01

    A characterization of the new Tsing Hua open-pool reactor (THOR) epithermal neutron beam designed for boron neutron capture therapy (BNCT) has been performed. The facility is currently under construction and expected in completion in March 2004. The designed epithermal neutron flux for 1 MW power is 1.7x10(9)n cm(-2)s(-1) in air at the beam exit, accompanied by photon and fast neutron absorbed dose rates of 0.21 and 0.47 mGys(-1), respectively. With (10)B concentrations in normal tissue and tumor of 11.4 and 40 ppm, the calculated advantage depth dose rate to the modified Snyder head phantom is 0.53RBE-Gymin(-1) at the advantage depth of 85 mm, giving an advantage ratio of 4.8. The dose patterns determined by the NCTPlan treatment planning system using the new THOR beam for a patient treated in the Harvard-MIT clinical trial were compared with results of the MITR-II M67 beam. The present study confirms the suitability of the new THOR beam for possible BNCT clinical trials. PMID:15308158

  10. 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

  11. Novel neutralized-beam intense neutron source for fusion technology development

    SciTech Connect

    Osher, J.E.; Perkins, L.J.

    1983-07-08

    We describe a neutralized-beam intense neutron source (NBINS) as a relevant application of fusion technology for the type of high-current ion sources and neutral beamlines now being developed for heating and fueling of magnetic-fusion-energy confinement systems. This near-term application would support parallel development of highly reliable steady-state higher-voltage neutral D/sup 0/ and T/sup 0/ beams and provide a relatively inexpensive source of fusion neutrons for materials testing at up to reactor-like wall conditions. Beam-target examples described incude a 50-A mixed D-T total (ions plus neutrals) space-charge-neutralized beam at 120 keV incident on a liquid Li drive-in target, or a 50-A T/sup 0/ + T/sup +/ space-charge-neutralized beam incident on either a LiD or gas D/sub 2/ target with calculated 14-MeV neutron yields of 2 x 10/sup 15//s, 7 x 10/sup 15//s, or 1.6 x 10/sup 16//s, respectively. The severe local heat loading on the target surface is expected to limit the allowed beam focus and minimum target size to greater than or equal to 25 cm/sup 2/.

  12. 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.}

  13. Design of a Thermal Neutron Beam for a New Neutron Imaging Facility at Tehran Research Reactor

    NASA Astrophysics Data System (ADS)

    Dastjerdi, Mohammad Hossein Choopan; Khalafi, Hossein

    A new neutron imaging facility will be built around the Tehran Research Reactor (TRR). The TRR is an open pool light water moderated5 MW research reactor with six beam tubes. The neutron energy spectrum near the reactor core at the entrance of the beam tube was measured by the foil activation method using the SAND-II code and calculated by the MCNP Monte Carlo code. There was a good similarity between calculated and simulated spectra. The principal component of this facility is its neutron collimator. The collimator is a beam-forming assembly which determines the geometric properties of the beam. In addition, it may contain filters to modify the energy spectrum or to reduce the gamma ray content of the beam. The optimum thickness of filters, the position of the aperture and other details of the neutron collimator were calculated using MCNP Monte Carlo simulations. In this design, the L/D ratio of this facility had the value of 120. The thermal neutron flux at the image plane was about 7.8×106 n/cm2.s and n/γ ratio about 106 n/cm2.μSv.

  14. 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

  15. Genetic Algorithms: A New Method for Neutron Beam Spectral Characterization

    SciTech Connect

    David W. Freeman

    2000-06-04

    A revolutionary new concept for solving the neutron spectrum unfolding problem using genetic algorithms (GAs) has recently been introduced. GAs are part of a new field of evolutionary solution techniques that mimic living systems with computer-simulated chromosome solutions that mate, mutate, and evolve to create improved solutions. The original motivation for the research was to improve spectral characterization of neutron beams associated with boron neutron capture therapy (BNCT). The GA unfolding technique has been successfully applied to problems with moderate energy resolution (up to 47 energy groups). Initial research indicates that the GA unfolding technique may well be superior to popular unfolding methods in common use. Research now under way at Kansas State University is focused on optimizing the unfolding algorithm and expanding its energy resolution to unfold detailed beam spectra based on multiple foil measurements. Indications are that the final code will significantly outperform current, state-of-the-art codes in use by the scientific community.

  16. 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.

  17. 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

  18. Characteristics of proton beams and secondary neutrons arising from two different beam nozzles

    NASA Astrophysics Data System (ADS)

    Choi, Yeon-Gyeong; Kim, Yu-Seok

    2015-10-01

    A tandem or a Van de Graaff accelerator with an energy of 3 MeV is typically used for Proton Induced X-ray Emission (PIXE) analysis. In this study, the beam line design used in the PIXE analysis, instead of the typical low-energy accelerator, was used to increase the production of isotopes from a 13-MeV cyclotron. For the PIXE analysis, the proton beam should be focused at the target through a nozzle after degrading the proton beams energy from 13 MeV to 3 MeV by using an energy degrader. Previous studies have been conducted to determine the most appropriate material for and the thickness of the energy degrader. From the energy distribution of the degraded proton beam and the neutron occurrence rate at the degrader, an aluminum nozzle of X thickness was determined to be the most appropriate nozzle construction. Neutrons are created by the collision of 3-MeV protons in the nozzle after passage through the energy degrader. In addition, a proton beam of sufficient intensity is required for a non-destructive PIXE analysis. Therefore, if nozzle design is to be optimized, the number of neutrons that arise from the collision of protons inside the nozzle, as well as the track direction of the generated secondary neutrons, must be considered, with the primary aim of ensuring that a sufficient number of protons pass through the nozzle as a direct beam. A number of laboratories are currently conducting research related to the design of nozzles used in accelerator fields, mostly medical fields. This paper presents a comparative analysis of two typical nozzle shapes in order to minimize the loss of protons and the generation of secondary neutrons. The neutron occurrence rate and the number of protons that pass through the nozzle were analyzed by using a Particle and Heavy Ion Transport code System (PHITS) program in order to identify the nozzle that generated the strongest proton beam.

  19. 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.

  20. 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. PMID:24448270

  1. 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

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

    PubMed

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

    2009-02-21

    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

  3. Neutron capture studies of 206Pb at a cold neutron beam

    NASA Astrophysics Data System (ADS)

    Schillebeeckx, P.; Belgya, T.; Borella, A.; Kopecky, S.; Mengoni, A.; Quétel, C. R.; Szentmiklósi, L.; Trešl, I.; Wynants, R.

    2013-11-01

    Gamma-ray transitions following neutron capture in 206Pb have been studied at the cold neutron beam facility of the Budapest Neutron Centre using a metallic sample enriched in 206Pb and a natural lead nitrate powder pellet. The measurements were performed using a coaxial HPGe detector with Compton suppression. The observed -rays have been incorporated into a decay scheme for neutron capture in 206Pb . Partial capture cross sections for 206Pb(n,) at thermal energy have been derived relative to the cross section for the 1884keV transition after neutron capture in 14N . From the average crossing sum a total thermal neutron capture cross section of mb was derived for the 206Pb(n,) reaction. The thermal neutron capture cross section for 206Pb has been compared with contributions due to both direct capture and distant unbound s-wave resonances. From the same measurements a thermal neutron-induced capture cross section of mb was determined for the 207Pb(n,) reaction.

  4. Characterization of a tunable quasi-monoenergetic neutron beam from deuteron breakup

    NASA Astrophysics Data System (ADS)

    Bleuel, D. L.; McMahan, M. A.; Ahle, L.; Barquest, B. R.; Cerny, J.; Heilbronn, L. H.; Jewett, C. C.

    2007-08-01

    A neutron irradiation facility is being developed at the 88-inch cyclotron at Lawrence Berkeley National Laboratory for the purposes of measuring neutron reaction cross sections on radioactive targets and for radiation effects testing. Applications are of benefit to stockpile stewardship, nuclear astrophysics, next generation advanced fuel reactors and cosmic radiation biology and electronics in space. The facility will supply a tunable, quasi-monoenergetic neutron beam in the range of 10-30 MeV or a white neutron source, produced by deuteron breakup reactions on thin and thick targets, respectively. Because the deuteron breakup reaction has not been well studied at intermediate incident deuteron energies, above the target Coulomb barrier and below 56 MeV, a detailed characterization was necessary of the neutron spectra produced by thin targets. Neutron time-of-flight (TOF) methods have been used to measure the neutron spectra produced on thin targets of low-Z (titanium) and high-Z (tantalum) materials at incident deuteron energies of 20 MeV and 29 MeV at 0°. Breakup neutrons at both energies from low-Z targets appear to peak at roughly half of the available kinetic energy, while neutrons from high-Z interactions peak somewhat lower in energy, owing to the increased proton energy due to breakup within the Coulomb field. Furthermore, neutron spectra appear narrower for high-Z targets. These centroids are consistent with recent preliminary proton energy measurements using silicon telescope detectors conducted at LBNL, though there is a notable discrepancy with spectral widths. Prospects for producing a tunable, quasi-monoenergetic neutron facility of 106-108 n/cm2/s at LBNL are promising.

  5. Beam intensity increases at the intense pulsed neutron source accelerator

    SciTech Connect

    Potts, C.; Brumwell, F.; Norem, J.; Rauchas, A.; Stipp, V.; Volk, G.

    1985-01-01

    The Intense Pulsed Neutron Source (IPNS) accelerator system has managed a 40% increase in time average beam current over the last two years. Currents of up to 15.6..mu..A (3.25 x 10/sup 12/ protons at 30 Hz) have been successfully accelerated and cleanly extracted. Our high current operation demands low loss beam handling to permit hands-on maintenance. Synchrotron beam handling efficiencies of 90% are routine. A new H/sup -/ ion source which was installed in March of 1983 offered the opportunity to get above 8 ..mu..A but an instability caused unacceptable losses when attempting to operate at 10 ..mu..A and above. Simple techniques to control the instabilities were introduced and have worked well. These techniques are discussed below. Other improvements in the regulation of various power supplies have provided greatly improved low energy orbit stability and contributed substantially to the increased beam current.

  6. Design of neutron beams for neutron capture therapy using a 300-kW slab TRIGA reactor

    SciTech Connect

    Liu, H.B.

    1995-03-01

    A design for a slab reactor to produce an epithermal neutron beam and a thermal neutron beam for use in neutron capture therapy (NCT) is described. A thin reactor with two large-area faces, a ``slab`` reactor, was planned using eighty-six 20% enriched TRIGA fuel elements and four B{sub 4}C control rods. Two neutron beams were designed: an epithermal neutron beam from one face and a thermal neutron beam from the other. The planned facility, based on this slab-reactor core with a maximum operating power of 300 kW, will provide an epithermal neutron beam of 1.8 {times} 10{sup 9} n{sub epi}/cm{sup 2}{center_dot}s intensity with low contamination by fast neutrons and gamma rays and a thermal neutron beam of 9.0 {times} 10{sup 9}n{sub th}/cm{sup 2}{center_dot}s intensity with low fast-neutron dose and gamma dose. Both neutron beams will be forward directed. Each beam can be turned on and off independently through its individual shutter. A complete NCT treatment using the designed epithermal or thermal neutron beam would take 30 or 20 min, respectively, under the condition of assuming 10{mu}g {sup 10}B/g in the blood. Such exposure times should be sufficiently short to maintain near-optimal target (e.g., {sup 10}B, {sup 157}Gd, and {sup 235}U) distribution in tumor versus normal tissues throughout the irradiation. With a low operating power of 300 kW, the heat generated in the core can be removed by natural convection through a pool of light water. The proposed design in this study could be constructed for a dedicated clinical NCT facility that would operate very safely.

  7. 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.

  8. 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.

  9. 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.

  10. Beam-transport optimization for cold-neutron spectrometer

    NASA Astrophysics Data System (ADS)

    Nakajima, Kenji; Ohira-Kawamura, Seiko; Kikuchi, Tatsuya; Kajimoto, Ryoichi; Takahashi, Nobuaki; Nakamura, Mitsutaka; Soyama, Kazuhiko; Osakabe, Toyotaka

    2015-01-01

    We report the design of the beam-transport system (especially the vertical geometry) for a cold-neutron disk-chopper spectrometer AMATERAS at J-PARC. Based on the elliptical shape, which is one of the most effective geometries for a ballistic mirror, the design was optimized to obtain, at the sample position, a neutron beam with high flux without serious degrading in divergence and spacial homogeneity within the boundary conditions required from actual spectrometer construction. The optimum focal point was examined. An ideal elliptical shape was modified to reduce its height without serious loss of transmission. The final result was adapted to the construction requirements of AMATERAS. Although the ideas studied in this paper are considered for the AMATERAS case, they can be useful also to other spectrometers in similar situations.

  11. Microdosimetric spectra of the THOR neutron beam for boron neutron capture therapy.

    PubMed

    Hsu, F Y; Tung, C J; Watt, D E

    2003-01-01

    A primary objective of the BNCT project in Taiwan, involving THOR (Tsing Hua Open Pool Reactor), was to examine the potential treatment of hepatoma. To characterise the epithermal neutron beam in THOR, the microdosimetry distributions in lineal energy were determined using paired tissue-equivalent proportional counters with and without boron microfoils. Microdosimetry results were obtained in free-air and at various depths in a PMMA phantom near the exit of the beam port. A biological weighting function, dependent on lineal energy, was used to estimate the relative biological effectiveness of the beam. An effective RBE of 2.7 was found at several depths in the phantom. PMID:12918789

  12. Reactions induced by beams of neutron and proton halo nuclei

    NASA Astrophysics Data System (ADS)

    Penionzhkevich, Yu. E.

    1997-02-01

    Within the collaboration Dubna-GANIL (Caen, France) - IPN (Orsay, France) - NPI (Rez, Czech Republic) - IAP (Bucharest, Romania) at GANIL and the Dubna U400M accelerator, experiments have been carried out to study elastic scattering, fusion and fission using secondary ion beams of 6He, 11Li and 8B. The fission cross-section for the 6He isotopes has been found to be significantly higher than for the 4He nuclei. This enhancement depends mainly on the entrance channel and it is connected with the neutron skin of the 6He nuclei. Also, investigation of the elastic scattering of 11Li (neutron halo), 7Be and 8B (proton halo) has been performed. The microscopic analysis supports the existence of a neutron halo in 11Li and the proton skin in 8B and 7Be. Perspectives for investigations in this field at the Laboratory of Nuclear Reactions JINR are also discussed.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Energetic neutron beams generated from femtosecond laser plasma interactions

    SciTech Connect

    Zulick, C.; Dollar, F.; Chvykov, V.; Kalinchenko, G.; Maksimchuk, A.; Raymond, A.; Thomas, A. G. R.; Willingale, L.; Yanovsky, V.; Krushelnick, K.; Davis, J.; Petrov, G. M.

    2013-03-25

    Experiments at the HERCULES laser facility have produced directional neutron beams with energies up to 16.8({+-}0.3) MeV using {sub 1}{sup 2}d(d,n){sub 2}{sup 3}He,{sub 7}{sup 3}Li(p,n){sub 4}{sup 7}Be,and{sub 3}{sup 7}Li(d,n){sub 4}{sup 8}Be reactions. Efficient {sub 1}{sup 2}Li(d,n){sub 4}{sup 8}Be reactions required the selective acceleration of deuterons through the introduction of a deuterated plastic or cryogenically frozen D{sub 2}O layer on the surface of a thin film target. The measured neutron yield was {<=}1.0 ({+-}0.5) Multiplication-Sign 10{sup 7} neutrons/sr with a flux 6.2({+-}3.7) times higher in the forward direction than at 90{sup Degree-Sign }. This demonstrates that femtosecond lasers are capable of providing a time averaged neutron flux equivalent to commercial {sub 1}{sup 2}d(d,n){sub 2}{sup 3}He generators with the advantage of a directional beam with picosecond bunch duration.

  18. 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

  19. On-line neutron beam monitoring of the Finnish BNCT facility

    NASA Astrophysics Data System (ADS)

    Tanner, Vesa; Auterinen, Iiro; Helin, Jori; Kosunen, Antti; Savolainen, Sauli

    1999-02-01

    A Boron Neutron Capture Therapy (BNCT) facility has been built at the FiR 1 research reactor of VTT Chemical Technology in Espoo, Finland. The facility is currently undergoing dosimetry characterisation and neutron beam operation research for clinical trials. The healthy tissue tolerance study, which was carried out in the new facility during spring 1998, demonstrated the reliability and user-friendliness of the new on-line beam monitoring system designed and constructed for BNCT by VTT Chemical Technology. The epithermal neutron beam is monitored at a bismuth gamma shield after an aluminiumfluoride-aluminium moderator. The detectors are three pulse mode U 235-fission chambers for epithermal neutron fluence rate and one current mode ionisation chamber for gamma dose rate. By using different detector sensitivities the beam intensity can be measured over a wide range of reactor power levels (0.001-250 kW). The detector signals are monitored on-line with a virtual instrumentation (LabView) based PC-program, which records and displays the actual count rates and total counts of the detectors in the beam. Also reactor in-core power instrumentation and control rod positions can be monitored via another LabView application. The main purpose of the monitoring system is to provide a dosimetric link to the dose in a patient during the treatment, as the fission chamber count rates have been calibrated to the induced thermal neutron fluence rate and to the absorbed dose rate at reference conditions in a tissue substitute phantom.

  20. Modification of the neutron beam spectrum for neutron radiography at Tehran Research Reactor (TRR)

    NASA Astrophysics Data System (ADS)

    Moghadam, K. Kamali; Ziaie, F.

    1996-02-01

    Recently due to the replacement of the High Enriched Uranium (HEU) fuel with the Low Enriched Uranium (LEU) fuel and the changes in the reactor core configuration at TRR, the existing Neutron Radiography (NR) system was no longer efficient. Thus, it was decided to modify the system in order to increase the neutron flux and to improve the characteristics of the system. The neutron energy spectrum was measured by foil activation method using SAND-II code and calculated by ANISN/PC code. The general trend of the calculated and measured spectra show good similarity. By introducing different sizes of moderator and gamma absorber behind the collimator, the optimum thermal neutron flux impinge the collimator was calculated using ANISN/PC code. The inlet diameter of the collimator was changed from 1.8 to 5 cm in order to increase the neutron flux at the sample position, which should result in an increase of 8 fold in spite of a small increase in the geometrical unsharpness. The new beam characteristics at the sample position are predicted as an average thermal neutron flux of about 10 6 n cm 2 s 1 and a neutron to gamma ratio of about 10 6 n cm 2 mR -1.

  1. BNCT dose distribution in liver with epithermal D-D and D-T fusion-based neutron beams.

    PubMed

    Koivunoro, H; Bleuel, D L; Nastasi, U; Lou, T P; Reijonen, J; Leung, K-N

    2004-11-01

    Recently, a new application of boron neutron capture therapy (BNCT) treatment has been introduced. Results have indicated that liver tumors can be treated by BNCT after removal of the liver from the body. At Lawrence Berkeley National Laboratory, compact neutron generators based on (2)H(d,n)(3)He (D-D) or (3)H(t,n)(4)He (D-T) fusion reactions are being developed. Preliminary simulations of the applicability of 2.45 MeV D-D fusion and 14.1 MeV D-T fusion neutrons for in vivo liver tumor BNCT, without removing the liver from the body, have been carried out. MCNP simulations were performed in order to find a moderator configuration for creating a neutron beam of optimal neutron energy and to create a source model for dose calculations with the simulation environment for radiotherapy applications (SERA) treatment planning program. SERA dose calculations were performed in a patient model based on CT scans of the body. The BNCT dose distribution in liver and surrounding healthy organs was calculated with rectangular beam aperture sizes of 20 cm x 20 cm and 25 cm x 25 cm. Collimator thicknesses of 10 and 15 cm were used. The beam strength to obtain a practical treatment time was studied. In this paper, the beam shaping assemblies for D-D and D-T neutron generators and dose calculation results are presented. PMID:15308157

  2. 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.

  3. Neutron beam studies for a medical therapy reactor.

    PubMed

    Neuman, W A

    1990-01-01

    A conceptual design of a Medical Therapy Reactor (MTR) for neutron capture therapy (NCT) has been performed at the Idaho National Engineering Laboratory (INEL). The initial emphasis of the conceptual design was toward the treatment of glioblastoma multiforme and other presently incurable cancers. The design goal of the facility is to provide routine patient treatments both in brief time intervals (approximately 10 minutes) and inexpensively. The conceptual study has shown this goal to be achievable by locating an MTR at a major medical facility. This paper addresses the next step in the conceptual design process: a guide to the optimization of the epithermal-neutron filter and collimator assembly for the treatment of brain tumors. The current scope includes the sensitivity of the treatment beam to variations in filter length, gamma shield length, and collimator lengths as well as exit beam aperture size. The study shows the areas which can provide the greatest latitude in improving beam intensity and quality. Suggestions are given for future areas of optimization of beam filtering and collimation. PMID:2268234

  4. 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.

  5. Neutron productions in the fragmentation of relativistic heavy nuclei and formation of a beam of high-energy neutrons

    NASA Astrophysics Data System (ADS)

    Yurevich, V. I.

    2016-03-01

    The production of quasimonoenergetic high-energy neutrons at zero angle (0°) in the spallation of relativistic heavy nuclei is discussed by considering the example of the interaction of lead nuclei with light target nuclei. It is shown that this process can be used to generate a beam of high-energy neutrons at existing heavy ion accelerators. At the same time, itmay lead to the appearance of a parasitic neutron beam because of the interaction of the heavy-ion beam used with beam line and experimental setup materials.

  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. 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%.

  8. 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

  9. 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

  10. 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

  11. New Pulsed Cold Neutron Beam Line for Fundamental Nuclear Physics at LANSCE

    PubMed Central

    Seo, P.-N.; Bowman, J. D.; Gericke, M.; Gillis, R. C.; Greene, G. L.; Leuschner, M. B.; Long, J.; Mahurin, R.; Mitchell, G. S.; Penttila, S. I.; Peralta, G.; Sharapov, E. I.; Wilburn, W. S.

    2005-01-01

    The NPDGamma collaboration has completed the construction of a pulsed cold neutron beam line on flight path12 at the Los Alamos Neutron Science Center (LANSCE). We describe the new beam line and characteristics of the beam. We report results of the moderator brightness and the guide performance measurements. FP12 has the highest pulsed cold neutron intensity for nuclear physics in the world. PMID:27308111

  12. New Pulsed Cold Neutron Beam Line for Fundamental Nuclear Physics at LANSCE.

    PubMed

    Seo, P-N; Bowman, J D; Gericke, M; Gillis, R C; Greene, G L; Leuschner, M B; Long, J; Mahurin, R; Mitchell, G S; Penttila, S I; Peralta, G; Sharapov, E I; Wilburn, W S

    2005-01-01

    The NPDGamma collaboration has completed the construction of a pulsed cold neutron beam line on flight path12 at the Los Alamos Neutron Science Center (LANSCE). We describe the new beam line and characteristics of the beam. We report results of the moderator brightness and the guide performance measurements. FP12 has the highest pulsed cold neutron intensity for nuclear physics in the world. PMID:27308111

  13. 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.

  14. np Elastic-scattering experiments with polarized neutron beams

    SciTech Connect

    Chalmers, J.S.; Ditzler, W.R.; Hill, D.; Hoftiezer, J.; Johnson, K.; Shima, T.; Shimizu, H.; Spinka, H.; Stanek, R.; Underwood, D.

    1985-01-01

    Measurements of the spin transfer parameters, K/sub NN/ and K/sub LL/, at 500, 650, and 800 MeV are presented for the reaction p-vector d ..-->.. n-vector pp at 0/sup 0/. The data are useful input to the NN data base and indicate that the quasi-free charge exchange (CEX) reaction is a useful mechanism for producing neutrons with at least 40% polarization at energies as low as 500 MeV. Measurements of np elastic scattering observables C/sub LL/ and C/sub SL/ covering 35/sup 0/ to 172/sup 0/ are performed using a polarized neutron beam at 500, 650, and 800 MeV. Preliminary results are presented. 3 refs., 6 figs.

  15. Dehydration process of fish analyzed by neutron beam imaging

    NASA Astrophysics Data System (ADS)

    Tanoi, K.; Hamada, Y.; Seyama, S.; Saito, T.; Iikura, H.; Nakanishi, T. M.

    2009-06-01

    Since regulation of water content of the dried fish is an important factor for the quality of the fish, water-losing process during drying (squid and Japanese horse mackerel) was analyzed through neutron beam imaging. The neutron image showed that around the shoulder of mackerel, there was a part where water content was liable to maintain high during drying. To analyze water-losing process more in detail, spatial image was produced. From the images, it was clearly indicated that the decrease of water content was regulated around the shoulder part. It was suggested that to prevent deterioration around the shoulder part of the dried fish is an important factor to keep quality of the dried fish in the storage.

  16. 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.

  17. Filtered epithermal quasi-monoenergetic neutron beams at research reactor facilities.

    PubMed

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

    2015-03-01

    Filtered neutron techniques were applied to produce quasi-monoenergetic neutron beams in the energy range of 1.5-133keV at research reactors. A simulation study was performed to characterize the filter components and transmitted beam lines. The filtered beams were characterized in terms of the optimal thickness of the main and additive components. The filtered neutron beams had high purity and intensity, with low contamination from the accompanying thermal emission, fast neutrons and γ-rays. A computer code named "QMNB" was developed in the "MATLAB" programming language to perform the required calculations. PMID:25544666

  18. Renovation of epithermal neutron beam for BNCT at THOR.

    PubMed

    Liu, Y-W H; Huang, T T; Jiang, S H; Liu, H M

    2004-11-01

    Heading for possible use for clinical trial, THOR (Tsing Hua Open-pool Reactor) at Taiwan was shutdown for renovation of a new epithermal neutron beam in January 2003. In November 2003, concrete cutting was finished for closer distance from core and larger treatment room. This article presents the design base that the construction of the new beam is based on. The filter/moderator design along the beam is Cd(0.1cm)+Al(10 cm)+FLUENTAL (16 cm)+Al(10 cm)+FLUENTAL(24 cm)+Void(18 cm)+Cd(0.1cm)+Bi(10 cm) with 6 cm Pb as reflector. Following the filter/moderator is an 88 cm long, 6 cm thick Bi-lined collimator with Li(2)CO(3)-PE at the end. The collimator is surrounded by Li(2)CO(3)-PE and Pb. The calculated beam parameters under 2 MW at the beam exit is phi(epi) = 3.4 x 10(9) n/cm(2)/s, Df/phi(epi) = 2.8 x 10(-11) cGy cm(2)/n, Dgamma/phi(epi) = 1.3 x 10(-11) cGy cm(2)/n, and J+/phi = 0.8. For a phantom placed 10 cm from beam exit, MCNP calculation shows that the advantage depth is 8.9 cm, and advantage ratio is 5.6 if boron concentration in tumor and normal tissue are assumed to be 65 and 18 ppm. The maximum dose rate for normal tissue is 50 cGy/min. The maximum therapeutic ratio is 6. The construction of the beam is scheduled to be finished by the end of April 2004. PMID:15308189

  19. Initial Performance Characterization for a Thermalized Neutron Beam for Neutron Capture Therapy Research at Washington State University

    SciTech Connect

    David W. Nigg; P.E> Sloan; J.R. Venhuizen; C.A. Wemple

    2005-11-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) and Washington State University (WSU) have constructed a new epithermal-neutron beam for collaborative Boron Neutron Capture Therapy (BNCT) preclinical research at the WSU TRIGATM research reactor facility1. More recently, additional beamline components were developed to permit the optional thermalization of the beam for certain types of studies where it is advantageous to use a thermal neutron source rather than an epithermal source. This article summarizes the results of some initial neutronic performance measurements for the thermalized system, with a comparison to the expected performance from the design computations.

  20. 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

  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. Development and characteristics of the HANARO neutron irradiation facility for applications in the boron neutron capture therapy field

    NASA Astrophysics Data System (ADS)

    Kim, Myong-Seop; Lee, Byung-Chul; Hwang, Sung-Yul; Kim, Heonil; Jun, Byung-Jin

    2007-05-01

    The HANARO neutron irradiation facility for various applications in the boron neutron capture therapy (BNCT) field was developed, and its characteristics were investigated. In order to obtain the sufficient thermal neutron flux with a low level of contamination by fast neutrons and gamma rays, a radiation filtering method was adopted. The radiation filter was designed by using a silicon single crystal, cooled by liquid nitrogen, and a bismuth crystal. The installation of the main components of the irradiation facility and the irradiation room was finished. Neutron beam characteristics were measured by using bare and cadmium-covered gold foils and wires. The in-phantom neutron flux distribution was measured for flux mapping inside the phantom. The gamma-ray dose was determined by using TLD-700 thermoluminescence dosimeters. The thermal and fast neutron fluxes and the gamma-ray dose were calculated by using the MCNP code, and they were compared with experimental data. The thermal neutron flux and Cd ratio available at this facility were confirmed to be 1.49 × 109 n cm-2 s-1 and 152, respectively. The maximum neutron flux inside the phantom was measured to be 2.79 × 109 n cm-2 s-1 at a depth of 3 mm in the phantom. The two-dimensional in-phantom neutron flux distribution was determined, and significant neutron irradiation was observed within 20 mm from the phantom surface. The gamma-ray dose rate for the free beam condition was expected to be about 80 cGy h-1. These experimental results were reasonably well supported by calculation using the facility design code. This HANARO thermal neutron facility can be used not only for clinical trials, but also for various pre-clinical studies in the BNCT field.

  3. Development and characteristics of the HANARO neutron irradiation facility for applications in the boron neutron capture therapy field.

    PubMed

    Kim, Myong-Seop; Lee, Byung-Chul; Hwang, Sung-Yul; Kim, Heonil; Jun, Byung-Jin

    2007-05-01

    The HANARO neutron irradiation facility for various applications in the boron neutron capture therapy (BNCT) field was developed, and its characteristics were investigated. In order to obtain the sufficient thermal neutron flux with a low level of contamination by fast neutrons and gamma rays, a radiation filtering method was adopted. The radiation filter was designed by using a silicon single crystal, cooled by liquid nitrogen, and a bismuth crystal. The installation of the main components of the irradiation facility and the irradiation room was finished. Neutron beam characteristics were measured by using bare and cadmium-covered gold foils and wires. The in-phantom neutron flux distribution was measured for flux mapping inside the phantom. The gamma-ray dose was determined by using TLD-700 thermoluminescence dosimeters. The thermal and fast neutron fluxes and the gamma-ray dose were calculated by using the MCNP code, and they were compared with experimental data. The thermal neutron flux and Cd ratio available at this facility were confirmed to be 1.49 x 10(9) n cm(-2) s(-1) and 152, respectively. The maximum neutron flux inside the phantom was measured to be 2.79 x 10(9) n cm(-2) s(-1) at a depth of 3 mm in the phantom. The two-dimensional in-phantom neutron flux distribution was determined, and significant neutron irradiation was observed within 20 mm from the phantom surface. The gamma-ray dose rate for the free beam condition was expected to be about 80 cGy h(-1). These experimental results were reasonably well supported by calculation using the facility design code. This HANARO thermal neutron facility can be used not only for clinical trials, but also for various pre-clinical studies in the BNCT field. PMID:17440252

  4. 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.

  5. 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.

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

    PubMed

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

    2015-07-01

    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 (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. PMID:26233385

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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 6Li. 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.

  8. 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.

  9. 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.

  10. Filter/moderator system for a BNCT beam of epithermal neutrons at nuclear reactor MARIA

    NASA Astrophysics Data System (ADS)

    Tyminska, Katarzyna

    2009-01-01

    Boron Neutron Capture Therapy is a very promising form of cancer therapy, consisting in irradiating a stable isotope of boron (10B) concentrated in tumor cells with a low energy neutron beam. This technique makes it possible to destroy tumor cells, leaving healthy tissues practically unaffected. In order to carry out the therapy in the proper way, the proper range of the neutron beam energy has to be chosen. In this paper we present a filter/moderator system modeled with MCNP code in order to obtain an epithermal neutron beam for BNCT post at MARIA reactor in Swierk.

  11. 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

  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. Singular perturbation applications in neutron transport

    SciTech Connect

    Losey, D.C.; Lee, J.C.

    1996-09-01

    This is a paper on singular perturbation applications in neutron transport for submission at the next ANS conference. A singular perturbation technique was developed for neutron transport analysis by postulating expansion in terms of a small ordering parameter {eta}. Our perturbation analysis is carried, without approximation, through {Omicron}({eta}{sup 2}) to derive a material interface correction for diffusion theory. Here we present results from an analytical application of the perturbation technique to a fixed source problem and then describe and implementation of the technique in a computational scheme.

  14. Dose homogeneity in boron neutron capture therapy using an epithermal neutron beam

    SciTech Connect

    Konijnenberg, M.W.; Dewit, L.G.H.; Mijnheer, B.J.

    1995-06-01

    Simulation models based on the neutron and photon Monte Carlo code MCNP were used to study the therapeutic possibilities of the HB11 epithermal neutron beam at the High Flux Reactor in Petten. Irradiations were simulated in two types of phantoms filled with water or tissue-equivalent material for benchmark treatment planning calculations. In a cuboid phantom the influence of different field sizes on the thermal-neutron-induced dose distribution was investigated. Various shapes of collimators were studied to test their efficacy in optimizing the thermal-neutron distribution over a planning target volume and healthy tissues. Using circular collimators of 8, 12 and 15 cm diameter it was shown that with the 15-cm field a relatively larger volume within 85% of the maximum neutron-induced dose was obtained than with the 8- or 12-cm-diameter field. However, even for this large field the maximum diameter of this volume was 7.5 cm. In an ellipsoid head phantom the neutron-induced dose was calculated assuming the skull to contain 10 ppm {sup 10}B, the brain 5 ppm {sup 10}B and the tumor 30 ppm {sup 10}B. It was found that with a single 15-cm-diameter circular beam a very inhomogeneous dose distribution in a typical target volume was obtained. Applying two equally weighted opposing 15-cm-diameter fields, however, a dose homogeneity within {+-} 10% in this planning target volume was obtained. The dose in the surrounding healthy brain tissue is 30% at maximum of the dose in the center of the target volume. Contrary to the situation for the 8-cm field, combining four fields of 15 cm diameter gave no large improvement of the dose homogeneity over the target volume or a lower maximum dose in the healthy brain. Therapy with BNCT on brain tumors must be performed either with an 8-cm four-field irradiation or with two opposing 15- or 12-cm fields to obtain an optimal dose distribution. 27 refs., 10 figs., 3 tabs.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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). PMID:21129990

  2. 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. PMID:26474209

  3. Fusion-neutron production in the TFTR with deuterium neutral beam injection

    SciTech Connect

    Hendel, H.W.; England, A.C.; Jassby, D.L.; Mirin, A.A.; Nieschmidt, E.B.

    1986-06-01

    We report measurements of the fusion reaction rate in the Tokamak Fusion Test Reactor (TFTR) covering a wide range of plasma conditions and injected neutral beam powers up to 6.3 MW. The fusion-neutron production rate in beam-injected plasmas decreases slightly with increasing plasma density n/sub e/, even though the energy confinement parameter n/sub e/tau/sub E/ generally increases with density. The measurements indicate and Fokker-Planck simulations show that with increasing density the source of fusion neutrons evolves from mainly beam-beam and beam-target reactions at very low n/sub e/ to a combination of beam-target and thermonuclear reactions at high n/sub e/. At a given plasma current, the reduction in neutron source strength at higher n/sub e/ is due to both a decrease in electron temperature and in beam-beam reaction rate. The Fokker-Planck simulations also show that at low n/sub e/, plasma rotation can appreciably reduce the beam-target reaction rate for experiments with co-injection only. The variation of neutron source strength with plasma and beam parameters is as expected for beam-dominated regimes. However, the Fokker-Planck simulations systematically overestimate the measured source strength by a factor of 2 to 3; the source of this discrepancy has not yet been identified.

  4. 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.

  5. Characterization of a thermal neutron beam monitor based on gas electron multiplier technology

    NASA Astrophysics Data System (ADS)

    Croci, Gabriele; Cazzaniga, Carlo; Claps, Gerardo; Tardocchi, Marco; Rebai, Marica; Murtas, Fabrizio; Vassallo, Espedito; Caniello, Roberto; Cippo, Enrico Perelli; Grosso, Giovanni; Rigato, Valentino; Gorini, Giuseppe

    2014-08-01

    Research into valid alternatives to 3He detectors is fundamental to the affordability of new neutron spallation sources like the European Spallation Source (ESS). In the case of ESS it is also essential to develop high-rate detectors that can fully exploit the increase of neutron flux relative to present neutron sources. One of the technologies fulfilling these requirements is the gas electron multiplier (GEM), since it can combine a high rate capability (MHz/mm2), a coverage area up to 1 m2 and a space resolution better than 0.5 mm. Its use as a neutron detector requires conversion of neutrons into charged particles. This paper describes the realization and characterization of a thermal neutron GEM-based beam monitor equipped with a cathode containing ^{10}B for neutron conversion. This device is constituted by a triple GEM detector whose cathode is made of an aluminum sheet covered by a 1 μ m thick ^{{nat}}B4C layer. The method used to realize a long-lasting ^{{nat}}B4C layer is described and the properties of such a layer have been determined. The detector performances (measured on the ISIS-VESUVIO beam line) in terms of beam profile reconstruction, imaging, and measurement of the thermal neutron beam energy spectrum are compatible with those obtained by standard beam monitors.

  6. Neutron beam optimization for boron neutron capture therapy using the D-D and D-T high-energy neutron sources

    SciTech Connect

    Verbeke, J.M.; Vujic, J.L.; Leung, K.N.

    2000-02-01

    A monoenergetic neutron beam simulation study is carried out to determine the most suitable neutron energy for treatment of shallow and deep-seated brain tumors in the context of boron neutron capture therapy. Two figures-of-merit--the absorbed skin dose and the absorbed tumor dose at a given depth in the brain--are used to measure the neutron beam quality. Based on the results of this study, moderators, reflectors, and delimiters are designed and optimized to moderate the high-energy neutrons from the fusion reactions {sup 2}H(d,n){sup 3}He and {sup 3}H(d,n){sup 4}He down to a suitable energy spectrum. Two different computational models (MCNP and BNCT-RTPE) have been used to study the dose distribution in the brain. With the optimal beam-shaping assembly, a 1-A mixed deuteron/triton beam of energy 150 keV accelerated onto a titanium target leads to a treatment time of 1 h. The dose near the center of the brain obtained with this configuration is > 65% higher than the dose from a typical spectrum produced by the Brookhaven Medical Research Reactor and is comparable to the dose obtained by other accelerator-produced neutron beams.

  7. Fan analyzer of neutron beam polarization on REMUR spectrometer at IBR-2 pulsed reactor

    NASA Astrophysics Data System (ADS)

    Nikitenko, Yu. V.; Ul'yanov, V. A.; Pusenkov, V. M.; Kozhevnikov, S. V.; Jernenkov, K. N.; Pleshanov, N. K.; Peskov, B. G.; Petrenko, A. V.; Proglyado, V. V.; Syromyatnikov, V. G.; Schebetov, A. F.

    2006-08-01

    The new spectrometer of polarized neutrons REMUR has been created and put in operation in the Frank Laboratory of Neutron Physics (JINR, Dubna). The spectrometer is dedicated to investigations of multiplayer structures and surfaces by registering the reflection of polarized neutrons and of the inhomogeneous state of solid matter by measuring the small-angle scattering of polarized neutrons. The spectrometer's working range of neutron wavelengths is 1.5-10 Å. The spectrometer is equipped with a linear position-sensitive detector and a focused supermirror polarization analyzer (fan-like polarization analyzer) with a solid angle of neutron detection of 2.2×10 -4 rad. This article describes the design and the principle of operation of the fan analyzer of neutron polarization together with the results of its tests on a polarized neutron beam.

  8. 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.

  9. 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.

  10. Magnetic compound refractive lens for focusing and polarizing cold neutron beams.

    PubMed

    Littrell, K C; te Velthuis, S G E; Felcher, G P; Park, S; Kirby, B J; Fitzsimmons, M R

    2007-03-01

    Biconcave cylindrical lenses are used to focus beams of x rays or neutrons using the refractive properties of matter. In the case of neutrons, the refractive properties of magnetic induction can similarly focus and simultaneously polarize the neutron beam without the concomitant attenuation of matter. This concept of a magnetic refractive lens was tested using a compound lens consisting of 99 pairs of cylindrical permanent magnets. The assembly successfully focused the intensity of a white beam of cold neutrons of one spin state at the detector, while defocusing the other. This experiment confirmed that a lens of this nature may boost the intensity locally by almost an order of magnitude and create a polarized beam. An estimate of the performance of a more practically dimensioned device suitable for incorporation in reflectometers and slit-geometry small angle scattering instruments is given. PMID:17411211

  11. 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.

  12. 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

  13. Spatial and spectral characteristics of a compact system neutron beam designed for BNCT facility.

    PubMed

    Ghassoun, J; Chkillou, B; Jehouani, A

    2009-04-01

    The development of suitable neutron sources and neutron beam is critical to the success of Boron Neutron Capture Therapy (BNCT). In this work a compact system designed for BNCT is presented. The system consists of (252)Cf fission neutron source and a moderator/reflector/filter/shield assembly. The moderator/reflector/filter arrangement has been optimized to maximize the epithermal neutron component which is useful for BNCT treatment of deep seated tumors with the suitably low level of beam contamination. The MCMP5 code has been used to calculate the different components of neutrons, secondary gamma rays originating from (252)Cf source and the primary gamma rays emitted directly by this source at the exit face of the compact system. The fluence rate distributions of such particles were also computed along the central axis of a human head phantom. PMID:19168369

  14. 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.

  15. 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.

  16. 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.

  17. 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.)

  18. Dose measurements and calculations in the epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR)

    SciTech Connect

    Fairchild, R.G.; Greenberg, D.; Kamen, Y.; Fiarman, S. . Medical Dept.); Benary, V. . Medical Dept. Tel Aviv Univ. ); Kalef-Ezra, J. . Medical Dept. Ioannina Univ. ); Wielopolski, L. . Medical Dept. State Univ. of New

    1990-01-01

    The characteristics of the epithermal neutron beam at BMRR were measured, calculated, and reported. This beam has already been used for animal irradiations. We anticipate that it will be used for clinical trials. Thermal and epithermal neutron flux densities distributions, and dose rate distributions, as a function of depth were measured in a lucite dog-head phantom. Monte Carlo calculations were performed and compared with the measured values. 2 refs., 4 figs., 1 tab.

  19. 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

  20. Production cross section of neutron-rich isotopes with radioactive and stable beams

    NASA Astrophysics Data System (ADS)

    Mun, Myeong-Hwan; Adamian, G. G.; Antonenko, N. V.; Oh, Yongseok; Kim, Youngman

    2014-03-01

    The production cross section of neutron-rich isotopes of Ca, Zn, Te, Xe, and Pt are predicted in the diffusive multinucleon transfer reactions with stable and radioactive beams. With these isotopes one can treat the neutron shell evolution beyond N =28, 50, 82, and 126. Because of the small cross sections, the production of nuclei near the neutron drip line requires the optimal choice of reaction partners and bombarding energies.

  1. 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.

  2. Toward neutron-rich nuclei via transfer reactions with stable and radioactive beams

    NASA Astrophysics Data System (ADS)

    Mun, Myeong-Hwan; Adamian, G. G.; Antonenko, N. V.; Oh, Yongseok; Kim, Youngman

    2015-05-01

    The possibilities of production of yet-undiscovered neutron-rich isotopes of Ca, Gd, Dy, Er, Yb, Hf, W, Os, Hg, Pb, and Th are explored in various multinucleon transfer reactions with stable and radioactive beams. The probable projectile-target combinations and bombarding energies to produce these neutron-rich isotopes are suggested for future experiments.

  3. 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.

  4. 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°.

  5. Flux and instrumentation upgrade for the epithermal neutron beam facility at Washington State University.

    PubMed

    Nigg, D W; Venhuizen, J R; Wemple, C A; Tripard, G E; Sharp, S; Fox, K

    2004-11-01

    An epithermal neutron beam facility for preclinical neutron capture therapy research has been constructed at the Washington State University TRIGA research reactor installation. Subsequent to a recent upgrade, this new facility offers a high-purity epithermal beam with intensity on the order of 1.2x10(9)n/cm(2)s. Key features include a fluoride-based design for the neutron filtering and moderating components as well as a novel collimator design that allows ease of assembly and disassembly of the beamline components. PMID:15308181

  6. Flux and Instrumentation Upgrade for the Epithermal Neutron Beam Facility at Washington State University

    SciTech Connect

    David W. Nigg; J.R. Venhuizen; C.E. Wemple; G. E. Tripard; S. Sharp; K. Fox

    2004-11-01

    An epithermal neutron beam facility for preclinical neutron capture therapy research has been constructed at the Washington State University TRIGA research reactor installation. Subsequent to a recent upgrade, this new facility offers a high-purity epithermal beam with intensity on the order of 1.2×109 n/cm2 s. Key features include a fluoride-based design for the neutron filtering and moderating components as well as a novel collimator design that allows ease of assembly and disassembly of the beamline components.

  7. Overview of the Conceptual Design of the Future VENUS Neutron Imaging Beam Line at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Bilheux, Hassina; Herwig, Ken; Keener, Scott; Davis, Larry

    VENUS (Versatile Neutron Imaging Beam line at the Spallation Neutron Source) will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to μm). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beam line 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS.

  8. 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.

  9. Microdosimetric measurements of radiation quality variations in homogeneous phantoms irradiated by fast neutron beams

    SciTech Connect

    Beach, J.L.; Milavickas, L.R.

    1982-01-01

    The Dual Radiation Action Theory of Kellerer and Rossi (DRA), along with presently available microdosimetric techniques, is applied to the detrmination of radiation quality variation within tissue equivalent phantoms irradiated by collimated fast neutron beams. The neutron beams investigated were produced by the bombardment of 22.5 and 16 MeV d+ on beryllium and by the T(d,n)/sup 4/He reaction (15-MeV neutrons). Microdosimetric spectra were obtained at points of varying depth and lateral distance from the central axis within a tissue equivalent phantom, including points within the penumbra. From the microdosimetric spectra the parameter RQ, a first approximation to RBE derived from DRA theory, is calculated for each point. All RQ values are calculated for the same level of effect. For these three different beams the results show that the RQ values for the total radiation spectrum of neutron and gamma radiation remain fairly constant with depth and with lateral distance from the beam axis at 2 and 10 cm depths. The largest central axis variation in RQ is 8% for the d(16)+Be beam. The largest variation between a penumbra and an on-axis RQ value is 4% at 2 cm depth in the d(22.5)+Be beam. The results for the d(22.5)+Be beam disagree with previously reported radiobiological results while the 15 MeV beam results are in good agreement.

  10. BEAM-LOSS DRIVEN DESIGN OPTIMIZATION FOR THE SPALLATION NEUTRON SOURCE (SNS) RING.

    SciTech Connect

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; CAMERON,P.; DANBY,G.; GARDNER,C.J.; JACKSON,J.; LEE,Y.Y.; LUDEWIG,H.; MALITSKY,N.; RAPARIA,D.; TSOUPAS,N.; WENG,W.T.; ZHANG,S.Y.

    1999-03-29

    This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Clinical evaluation of neutron beam therapy. Current results and prospects, 1983

    SciTech Connect

    Cohen, L.; Hendrickson, F.R.; Kurup, P.D.; Mansell, J.A.; Awschalom, M.; Rosenberg, I.; Ten Haken, R.K.

    1985-01-01

    Some 9000 patients throughout the world have been treated by some form of neutron beam therapy. These include patients with advanced nonresectable tumors in many different sites treated with a variety of neutron beam generators varying widely in beam energy. Protocols were largely nonrandomized and included both mixed beam studies (neutrons + photons) and neutrons alone in varying doses. In spite of wide variation in equipment, treatment technique, and philosophy, some consistent trends have been identified: (1) in general, the neutron results have been at least as good as those of the photon controls measured in terms of local control, although the incidence of significant side effects have been higher; (2) in none of the randomized studies conducted so far, largely comprising epidermoid carcinomas of the head and neck, has a clear survival advantage for neutrons over photon controls been demonstrated at a statistically significant level; (3) results with mixed beam studies have been uniformly equivocal, with marginally significant differences in favor of the experimental groups compared with the photon controls; (4) adenocarcinomas of the gastrointestinal tract (GI) tract, including tumors of the salivary gland, pancreas, stomach, and bowel, appear to be responsive to high linear energy transfer (LET) radiation; (5) nonepidermoid, radioresistant tumors (sarcoma of bone and soft tissue and melanoma) yield a consistantly high local control rate, with neutron irradiation strikingly superior to those reported with photon therapy; and (6) in the central nervous system, both normal tissues and tumors appear to be exceptionally sensitive to neutron irradiation, therapeutic ratios are small, and the prospect of cure remains remote. It is concluded that neutrons are efficacious for certain specific tumor types, but that essentially new study designs, based on nonrandomized matched case comparisons, will be required to prove the merit of the new modality.

  16. 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

  17. 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

  18. 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.

  19. Coarse-scaling adjustment of fine-group neutron spectra for epithermal neutron beams in BNCT using multiple activation detectors

    NASA Astrophysics Data System (ADS)

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

    2009-01-01

    In order to provide an improved and reliable neutron source description for treatment planning in boron neutron capture therapy (BNCT), a spectrum adjustment procedure named coarse-scaling adjustment has been developed and applied to the neutron spectrum measurements of both the Tsing Hua Open-pool Reactor (THOR) epithermal neutron beam in Taiwan and the High Flux Reactor (HFR) in The Netherlands, using multiple activation detectors. The coarse-scaling adjustment utilizes a similar idea as the well-known two-foil method, which adjusts the thermal and epithermal neutron fluxes according to the Maxwellian distribution for thermal neutrons and 1/ E distribution over the epithermal neutron energy region. The coarse-scaling adjustment can effectively suppress the number of oscillations appearing in the adjusted spectrum and provide better smoothness. This paper also presents a sophisticated 9-step process utilizing twice the coarse-scaling adjustment which can adjust a given coarse-group spectrum into a fine-group structure, i.e. 640 groups, with satisfactory continuity and excellently matched reaction rates between measurements and calculation. The spectrum adjustment algorithm applied in this study is the same as the well-known SAND-II.

  20. 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.

  1. 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

  2. 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

  3. Applications of {sup 3}He neutron detectors

    SciTech Connect

    Testov, D. A.; Briancon, Ch.; Dmitriev, S. N.; Yeremin, A. V.; Penionzhkevich, Yu. E.; Pyatkov, Yu. V.; Sokol, E. A.

    2009-01-15

    Neutron detectors with {sup 3}He-filled proportional counters are described. The use of these detectors in measuring the probability of neutron emission (in particular, multiparticle neutron emission) after the {beta} decay of neutron-rich nuclei and in studying rare events of spontaneous fission of superheavy nuclei is considered.

  4. Comparative study of MC-50 and ANITA neutron beams by using 55 nm SRAM

    NASA Astrophysics Data System (ADS)

    Baeg, Sanghyeon; Lee, Soonyoung; Bak, Geun Yong; Jeong, Hyunsoo; Jeon, Sang Hoon

    2012-09-01

    Single event upset (SEU) is mainly caused by neutrons in the terrestrial environment. In addition, SEU effects become more and more problematic as technology scales. It is, therefore, important to understand the SEU behaviors of semiconductor devices under neutron reactions. ANITA (atmospheric-like neutrons from thick target) in TSL (The Svedberg Laboratory), Sweden, resembles the neutron energy and flux spectrum to neutrons at the terrestrial level and are typically used to estimate the soft error rate (SER). On the other hand, the neutron energy and flux spectrum from the MC-50 cyclotron at KIRAMS (Korea Institute of Radiological & Medical Sciences) differs greatly from the atmospheric environment. The main objective of this work is finding the efficacy of the neutron beam at KIRAMS for a SEU analysis by using a comparative analysis; 55 nm SRAM is used to determine SEU difference under the beams at two different locations. Since MCU (multi-cell upset) is the dominant effect in emerging technologies with smaller critical charges, the MCU cross sections from the two different beam tests are compared.

  5. Optimum design and criticality safety of a beam-shaping assembly with an accelerator-driven subcritical neutron multiplier for boron neutron capture therapies.

    PubMed

    Hiraga, F

    2015-12-01

    The beam-shaping assembly for boron neutron capture therapies with a compact accelerator-driven subcritical neutron multiplier was designed so that an epithermal neutron flux of 1.9×10(9) cm(-2) s(-1) at the treatment position was generated by 5 MeV protons in a beam current of 2 mA. Changes in the atomic density of (135)Xe in the nuclear fuel due to the operation of the beam-shaping assembly were estimated. The criticality safety of the beam-shaping assembly in terms of Xe poisoning is discussed. PMID:26235186

  6. 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.

  7. Quasiparticle Interactions in Neutron Matter for Applications in Neutron Stars

    NASA Technical Reports Server (NTRS)

    Wambach, J.; Anisworth, T. L.; Pines, D.

    1993-01-01

    A microscopic model for the quaisiparticle interaction in neutron matter is presented. Both particle-particle (pp) and particle-hole (ph) correlation are are included. The pp correlations are treated in semi-empirical way, while ph correlations are incorporated by solving coupled two-body equations for the particle hole interaction and the scattering amplitude on the Fermi sphere. The resulting integral equations self-consistently sum the ph reducible diagrams. Antisymmetry is kept at all stages and hence the forward-scattering sum rules are obeyed. Results for Landau parameters and transport coefficients in a density regime representing the crust of a neutron star are presented. We also estimate the S-1 gap parameter for neutron superfluidity and comment briefly on neutron-star implications.

  8. Quasiparticle Interactions in Neutron Matter for Applications in Neutron Stars

    NASA Technical Reports Server (NTRS)

    Wambach, J; Ainsworth, T. L.; Pines, D.

    1993-01-01

    A microscopic model for the quasiparticle interaction in neutron matter is presented. Both-particle (pp) and particle-hole (ph) correlations are included. The pp correlations are treated in semi-empirical way, while ph correlations are incorporated by solving coupled two-body equations for particle-hole interaction and the scattering amplitude of the Fermi sphere. The resulting integral equations self-consistently sum the ph reducible diagrams. Antisymmetry is kept at all stages and hence the forward-scattering sum rules for the scattering amplitude are obeyed. Results for Landau parameters and transport coefficients in a density regime representing the crust of a neutron star are presented. We also estimate the (1)S(sub 0) gap parameter for neutron superfluidity and comment briefly on neutron-star implications.

  9. Laser wire beam profile monitor in the spallation neutron source (SNS) superconducting linac

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Aleksandrov, A.; Assadi, S.; Blokland, W.; Deibele, C.; Grice, W.; Long, C.; Pelaia, T.; Webster, A.

    2010-01-01

    The spallation neutron source (SNS) at Oak Ridge National Laboratory is an accelerator-based, neutron-scattering facility. SNS uses a large-scale, high-energy superconducting linac (SCL) to provide high beam power utilizing hydrogen ion (H -) beams. For the diagnostics of high-brightness H - beams in the SCL, nonintrusive methods are preferred. This paper describes design, implementation, theoretical analysis, and experimental demonstration of a nonintrusive profile monitor system based on photodetachment, also known as laser wire, installed in the SNS SCL. The SNS laser wire system is the world's largest of its kind with a capability of measuring horizontal and vertical profiles of an operational H - beam at each of the 23 cryomodule stations along the SCL beam line by employing a single light source. Presently 9 laser wire stations have been commissioned that measure profiles of the H - beam at energy levels from 200 MeV to 1 GeV. The laser wire diagnostics has no moving parts inside the beam pipe, causes no contamination on the superconducting cavity, and can be run parasitically on an operational neutron production H - beam.

  10. Peregrine monte carlo dose calculations for radiotherapy using clinically realistic neutron and proton beams

    SciTech Connect

    Cox, L. J., LLNL

    1997-06-16

    Lawrence Livermore National Laboratory (LLNL) has developed an all-particle Monte Carlo radiotherapy dose calculation code--PEREGRINE--for use in clinical radiation oncology. For PEREGRINE, we have assembled high-energy evaluated nuclear databases; created radiation source characterization and sampling algorithms; and simulated and characterized clinical beams for treatment with photons, neutrons and protons. Spectra are available for the Harper Hospital (Detroit, U.S.A.) Be(d,n) neutron therapy beam, the National Accelerator Centre (NAC, Faure, S.A.) Be(p,n) neutron therapy beam and many of the operating modes of the Loma Linda University Medical Center (LLUMC, Loma Linda, USA) proton treatment center. These beam descriptions are being used in PEREGRINE for Monte Carlo dose calculations on clinical configurations for comparisons to measurements. The methods of defining and sampling the beam phase space characterizations are discussed. We show calculations using these clinical beams compared to measurements in homogeneous water phantoms. The state of PEREGRINE's high energy neutron and proton transport database, PCSL, is reviewed and the remaining issues involving nuclear data needs for PEREGRINE are addressed.

  11. 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.

  12. 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.

  13. 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

  14. Effects On Beam Alignment Due To Neutron-Irradiated CCD Images At The National Ignition Facility

    SciTech Connect

    Awwal, A; Manuel, A; Datte, P; Burkhart, S

    2011-02-28

    The 192 laser beams in the National Ignition Facility (NIF) are automatically aligned to the target-chamber center using images obtained through charged coupled device (CCD) cameras. Several of these cameras are in and around the target chamber during an experiment. Current experiments for the National Ignition Campaign are attempting to achieve nuclear fusion. Neutron yields from these high energy fusion shots expose the alignment cameras to neutron radiation. The present work explores modeling and predicting laser alignment performance degradation due to neutron radiation effects, and demonstrates techniques to mitigate performance degradation. Camera performance models have been created based on the measured camera noise from the cumulative single-shot fluence at the camera location. We have found that the effect of the neutron-generated noise for all shots to date have been well within the alignment tolerance of half a pixel, and image processing techniques can be utilized to reduce the effect even further on the beam alignment.

  15. The new vertical neutron beam line at the CERN n_TOF facility design and outlook on the performance

    NASA Astrophysics Data System (ADS)

    Weiß, C.; Chiaveri, E.; Girod, S.; Vlachoudis, V.; Aberle, O.; Barros, S.; Bergström, I.; Berthoumieux, E.; Calviani, M.; Guerrero, C.; Sabaté-Gilarte, M.; Tsinganis, A.; Andrzejewski, J.; Audouin, L.; Bacak, M.; Balibrea-Correa, J.; Barbagallo, M.; Bécares, V.; Beinrucker, C.; Belloni, F.; Bečvář, F.; Billowes, J.; Bosnar, D.; Brugger, M.; Caamaño, M.; Calviño, F.; Cano-Ott, D.; Cerutti, F.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Cosentino, L.; Damone, L.; Deo, K.; Diakaki, M.; Domingo-Pardo, C.; Dupont, E.; Durán, I.; Dressler, R.; Fernández-Domínguez, B.; Ferrari, A.; Ferreira, P.; Finocchiaro, P.; Frost, R.; Furman, V.; Ganesan, S.; Gheorghe, A.; Glodariu, T.; Göbel, K.; Gonçalves, I. F.; González-Romero, E.; Goverdovski, A.; Griesmayer, E.; Gunsing, F.; Harada, H.; Heftrich, T.; Heinitz, S.; Hernández-Prieto, A.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Katabuchi, T.; Kavrigin, P.; Ketlerov, V.; Khryachkov, V.; Kimura, A.; Kivel, N.; Kokkoris, M.; Krtička, M.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Lerendegui, J.; Licata, M.; Lo Meo, S.; López, D.; Losito, R.; Macina, D.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Matteucci, F.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Montesano, S.; Musumarra, A.; Nolte, R.; Palomo Pinto, R.; Paradela, C.; Patronis, N.; Pavlik, A.; Perkowski, J.; Porras, I.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego-Perez, A.; Robles, M. S.; Rubbia, C.; Ryan, J.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Sedyshev, P.; Smith, G.; Stamatopoulos, A.; Steinegger, P.; Suryanarayana, S. V.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tassan-Got, L.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vlastou, R.; Wallner, A.; Warren, S.; Weigand, M.; Wright, T.; Žugec, P.

    2015-11-01

    At the neutron time-of-flight facility n_TOF at CERN a new vertical beam line was constructed in 2014, in order to extend the experimental possibilities at this facility to an even wider range of challenging cross-section measurements of interest in astrophysics, nuclear technology and medical physics. The design of the beam line and the experimental hall was based on FLUKA Monte Carlo simulations, aiming at maximizing the neutron flux, reducing the beam halo and minimizing the background from neutrons interacting with the collimator or back-scattered in the beam dump. The present paper gives an overview on the design of the beam line and the relevant elements and provides an outlook on the expected performance regarding the neutron beam intensity, shape and energy resolution, as well as the neutron and photon backgrounds.

  16. Geant4 simulation of the n_TOF-EAR2 neutron beam: Characteristics and prospects

    NASA Astrophysics Data System (ADS)

    Lerendegui-Marco, J.; Lo Meo, S.; Guerrero, C.; Cortés-Giraldo, M. A.; Massimi, C.; Quesada, J. M.; Barbagallo, M.; Colonna, N.; Mancusi, D.; Mingrone, F.; Sabaté-Gilarte, M.; Vannini, G.; Vlachoudis, V.

    2016-04-01

    The characteristics of the neutron beam at the new n_TOF-EAR2 facility have been simulated with the Geant4 code with the aim of providing useful data for both the analysis and planning of the upcoming measurements. The spatial and energy distributions of the neutrons, the resolution function and the in-beam γ-ray background have been studied in detail and their implications in the forthcoming experiments have been discussed. The results confirm that, with this new short (18.5m flight path) beam line, reaching an instantaneous neutron flux beyond 105n/μs/pulse in the keV region, n_TOF is one of the few facilities where challenging measurements can be performed, involving in particular short-lived radioisotopes.

  17. 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.

  18. 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. PMID:24374405

  19. Development and demonstration of a multi-channel spheroidal focusing device for neutron beams

    NASA Astrophysics Data System (ADS)

    Hayashida, H.; Soyama, K.; Yamazaki, D.; Maruyama, R.; Yamamura, K.

    2014-07-01

    A multi-channel neutron focusing mirror is a compact device that can effectively enhance neutron intensity because the multi-channel structure can cover a large divergence of a neutron beam. In this study, we attempted to develop a compact multi-channel spheroidal (MS) neutron focusing device for two-dimensional focusing. A prototype of the MS mirror consists of three spheroidal mirrors of different diameters. The mirrors are fabricated through the copper plating method without supermirror coating and are aligned coaxially using ring-shaped spacers. The MS mirror was demonstrated at beam line 10 NOBORU port at J-PARC, which provides neutron beams with time-of-flight spectra. A gain factor of 6 in neutron intensity was obtained over wavelengths greater than 0.5 nm, and an imaging test with sample scanning could be performed with an exposure time of 10 s. A Gd-patterned standard sample was employed and a 2D image with a spatial resolution of 200 μm was successfully obtained.

  20. 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. PMID:21621416

  1. Application of neutron holography to polycrystalline samples

    NASA Astrophysics Data System (ADS)

    Szakál, A.; Markó, M.; Krexner, G.; Cser, L.

    2015-07-01

    Neutron holography can be an efficient tool to investigate the local real-space structure of crystalline materials around specific probe nuclei serving as radiation source or detector. The positions of atoms in the neighborhood of such nuclei are observable with high (picometry) accuracy. Measurements of this type require orientational order and, therefore, restrict the range of study essentially to single crystals. However, if the information searched for is limited to the distances between the probe and the surrounding nuclei instead of their positions, holographic techniques can be applied to polycrystalline samples as well. In order to prove this statement, the expected multi-wavelength holographic signal of a polycrystalline sample was calculated. The holographic signal can be obtained by applying time-of-flight techniques, and by using a proper mathematical procedure, the distances between the probe nucleus and the surrounding nuclei can be reconstructed. A model calculation taking into account real instrument parameters confirms this expectation. The experimental verification of the predictions can be undertaken at existing pulsed neutron sources being able to provide the required experimental conditions. This new method opens the way to expand the field of investigation towards gaining information about the local atomic structure of polycrystalline materials which are of importance also in various applications.

  2. Validation of the Pinnacle³ photon convolution-superposition algorithm applied to fast neutron beams.

    PubMed

    Kalet, Alan M; Sandison, George A; Phillips, Mark H; Parvathaneni, Upendra

    2013-01-01

    We evaluate a photon convolution-superposition algorithm used to model a fast neutron therapy beam in a commercial treatment planning system (TPS). The neutron beam modeled was the Clinical Neutron Therapy System (CNTS) fast neutron beam produced by 50 MeV protons on a Be target at our facility, and we implemented the Pinnacle3 dose calculation model for computing neutron doses. Measured neutron data were acquired by an IC30 ion chamber flowing 5 cc/min of tissue equivalent gas. Output factors and profile scans for open and wedged fields were measured according to the Pinnacle physics reference guide recommendations for photon beams in a Wellhofer water tank scanning system. Following the construction of a neutron beam model, computed doses were then generated using 100 monitor units (MUs) beams incident on a water-equivalent phantom for open and wedged square fields, as well as multileaf collimator (MLC)-shaped irregular fields. We compared Pinnacle dose profiles, central axis doses, and off-axis doses (in irregular fields) with 1) doses computed using the Prism treatment planning system, and 2) doses measured in a water phantom and having matching geometry to the computation setup. We found that the Pinnacle photon model may be used to model most of the important dosimetric features of the CNTS fast neutron beam. Pinnacle-calculated dose points among open and wedged square fields exhibit dose differences within 3.9 cGy of both Prism and measured doses along the central axis, and within 5 cGy difference of measurement in the penumbra region. Pinnacle dose point calculations using irregular treatment type fields showed a dose difference up to 9 cGy from measured dose points, although most points of comparison were below 5 cGy. Comparisons of dose points that were chosen from cases planned in both Pinnacle and Prism show an average dose difference less than 0.6%, except in certain fields which incorporate both wedges and heavy blocking of the central axis. All

  3. 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.

  4. Compact D-D Neutron Source-Driven Subcritical Multiplier and Beam-Shaping Assembly for Boron Neutron Capture Therapy

    SciTech Connect

    Francesco Ganda; Jasmina Vujic; Ehud Greenspan; Ka-Ngo Leung

    2010-12-01

    This work assesses the feasibility of using a small, safe, and inexpensive keff 0.98 subcritical fission assembly [subcritical neutron multiplier (SCM)] to amplify the treatment neutron beam intensity attainable from a compact deuterium-deuterium (D-D) fusion neutron source delivering [approximately]1012 n/s. The objective is to reduce the treatment time for deep-seated brain tumors to [approximately]1 h. The paper describes the optimal SCM design and two optimal beam-shaping assemblies (BSAs) - one designed to maximize the dose rate and the other designed to maximize the total dose that can be delivered to a deep-seated tumor. The neutron beam intensity amplification achieved with the optimized SCM and BSA results in an increase in the treatment dose rate by a factor of 18: from 0.56 Gy/h without the SCM to 10.1 Gy/h. The entire SCM is encased in an aluminum structure. The total amount of 20% enriched uranium required for the SCM is 8.5 kg, and the cost (not including fabrication) is estimated to be less than $60,000. The SCM power level is estimated at 400 W when driven by a 1012 n/s D-D neutron source. This translates into consumption of only [approximately]0.6% of the initially loaded 235U atoms during 50 years of continuous operation and implies that the SCM could operate continuously for the entire lifetime of the facility without refueling. Cooling the SCM does not pose a challenge; it may be accomplished by natural circulation as the maximum heat flux is only 0.034 W/cm2.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Dosimetry of fast neutron beams using CaSO 4:Dy (TLD-900) pellets

    NASA Astrophysics Data System (ADS)

    Pradhan, A. S.; Rassow, J.; Meissner, P.

    1985-05-01

    This paper describes the use of commercially avialable CaSO 4:Dy (TLD-900) pellets for the measurement of absorbed doses of fast neutrons and gamma rays in mixed fields with one single detector. The gamma ray absorbed doses could be estimated by recording the thermoluminiscence (TL) induced during the neutron beam irradiations, whereas the fast neutron absorbed doses were measured by employing a post-irradiation TL accumulation due to activation of sulphur by the threshold nuclear reaction 32S(n, p) 32P in CaSO 4:Dy.

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

    NASA Astrophysics Data System (ADS)

    Appelbe, B.; Chittenden, J.

    2015-10-01

    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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Medical applications of ion beam processes

    NASA Astrophysics Data System (ADS)

    Sioshansi, P.

    The use of ions beams for treatment of surfaces in medical prostheses has gained increasing interest in the past few years. The application of ion beams has taken different forms: (1) ion implantation has been used for increasing the hardness and wear resistance of the new generation titanium based alloys, as well as reducing the wear of the mating polyethylene component used in orthopedic total joint replacement. Spire Corporation has been successful in commercializing ion implantation technology and is processing several thousand artificial knees and hips per year. (Spire uses the tradename IONGUARD™ for this application.) (2) Similarly, ion implantation has proven to be very effective for increasing the corrosion resistance of the Co-Cr based alloys that have traditionally been used in orthopedic prostheses. This application should be of particular interest in resolving the issues surrounding ion release problems associated with these alloys. (3) Ion beam etching/milling has been used for producing a highly textured surface for tissue ingrowth in applications ranging from porous orthopedic implants and percutaneous devices to artificial skin and the process should have a significant impact in this application. (4) There are indications that ion implantation is a useful process for increasing biocompatibility and tissue attachment on metallic samples. This subject deserves considerable attention in the coming years.

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

    SciTech Connect

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

    2012-02-15

    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.

  18. The formation of an ion beam in a vacuum neutron tube

    NASA Astrophysics Data System (ADS)

    Agafonov, A. V.; Tarakanov, V. P.

    2014-09-01

    The formation of a deuteron beam in a diode with a plasma emitter that is integrated into the structure of a vacuum neutron tube is considered. Computations are carried out for plasma with given time dependences of parameters (density, relative concentration, and expansion velocity) at the inlet to an accelerating gap. It is shown that it is possible to increase the ion-beam current possible by sectioning the diode at the given external parameters.

  19. 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.

  20. 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

  1. 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

  2. Endodontic applications of cone beam computed tomography.

    PubMed

    McClammy, Thomas V

    2014-07-01

    Cone-beam CT (CBCT) has made a dramatic contribution and has been quickly adopted in endodontics. It is a game changer in research and clinical applications. Although CBCT and its application in implantology is well known, the surgical placement of implants is now a factor in endodontics. This article illustrates unique applications of CBCT in implantology in a specialty endodontic facility. Endodontics creates the foundation for restorative dentistry for a healthy tooth, a well-treated endodontically treated tooth, or a well-placed dental implant. CBCT helps make this possible and predictable. PMID:24993923

  3. 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

  4. 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. PMID:7869995

  5. Interaction of High-Energy Proton Beam with a Thin Target and Multiplicities of Neutron

    SciTech Connect

    Demirkol, I.; Tatar, M.; Safak, M. S.; Arasoglu, A.; Tel, E.

    2007-04-23

    An important ingredient in the performance of accelerator driven systems for energy production, waste transmutation and other applications are the number of spallation neutrons produced per incident proton. The neutron multiplicities, angular and energy distributions are usually calculated using simulation codes. We have presented multiplicities of the neutrons emitted in the interaction of a high-energy proton (1500 MeV) with a thin target Pb, Bi. In this study we have used the code ISABEL to calculate multiplicities of the neutron emitted. The results obtained have been compared with the available data.

  6. 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. PMID:26595777

  7. 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.

  8. 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.

  9. A beam-modification assembly for experimental neutron capture therapy of brain tumors

    SciTech Connect

    Slatkin, D.N.; Kalef-Ezra, J.A.; Saraf, S.K.; Joel, D.D.

    1989-01-01

    Recent attempts to treat intracerebral rat gliomas by boron neutron capture therapy (BNCT) have been somewhat disappointing, perhaps in part because of excessive whole-body and nasopharyngeal irradiation. Intracerebral rat gliomas were treated by BNCT with more success using a new beam-modification assembly. 3 refs., 2 figs.

  10. Polarized Neutron Beam at the SANS Diffractometer KWS2 of the JCNS

    NASA Astrophysics Data System (ADS)

    Ioffe, A.; Feoktystov, A.; Staringer, S.; Radulescu, A.; Babcock, E.; Salhi, Z.

    This article describes a high-efficiency transmission polarizer that has been installed at the high-intensity SANS diffractometer KWS2 of the Jülich Centre for Neutron Science. The polarizer is primarily designed to be used in the low resolution/high Q-range mode of this diffractometer for the purpose of the separation of coherent scattering on biological objects from an intrinsic background caused by incoherent scattering on their hydrogen atoms. The polarizer operates with a rather divergent incident beam and is placed at about 2m from the sample (upstream in the beam). The diffuse spin-flip scattering that would become critical for such geometry is suppressed due to the use of a strong, about 0.14T, magnetic field. The polarizer has been characterized by a 3He neutron spin filter and provides very high polarization - 93% at 4.5 Å and 99.7% for neutrons with wavelength above 6 Å - for the SANS collimation 4m. The polarizer transmission at 4.5 Å amounts to 94% of the desired spin component. The polarizer is placed in the collimation base of the instrument and can be easily put in and out of the beam thus allowing for "an instant" switch between polarized and non-polarized neutron beams.