Science.gov

Sample records for neutron beam instruments

  1. 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.

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

    SciTech Connect

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

    1982-01-01

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

  3. Diamonds for beam instrumentation

    SciTech Connect

    Griesmayer, Erich

    2013-04-19

    Diamond is perhaps the most versatile, efficient and radiation tolerant material available for use in beam detectors with a correspondingly wide range of applications in beam instrumentation. Numerous practical applications have demonstrated and exploited the sensitivity of diamond to charged particles, photons and neutrons. In this paper, a brief description of a generic diamond detector is given and the interaction of the CVD diamond detector material with protons, electrons, photons and neutrons is presented. Latest results of the interaction of sCVD diamond with 14 MeV mono-energetic neutrons are shown.

  4. A single-crystal diamond-based thermal neutron beam monitor for instruments at pulsed neutron sources

    NASA Astrophysics Data System (ADS)

    Pietropaolo, A.; Verona Rinati, G.; Verona, C.; Schooneveld, E. M.; Angelone, M.; Pillon, M.

    2009-11-01

    Single-crystal diamond detectors manufactured through a Chemical Vapour Deposition (CVD) technique are recent technology devices that have been employed in reactor and Tokamak environments in order to detect both thermal and almost monochromatic 14 MeV neutrons produced in deuterium-tritium ( d-t) nuclear fusion reactions. Their robustness and compactness are the key features that can be exploited for different applications as well. Aim of the present experimental investigation is the assessment of the performance of a diamond detector as a thermal neutron beam monitor at pulsed neutron sources. To this aim, a test measurement was carried out on the Italian Neutron Experimental Station (INES) beam line at the ISIS spallation neutron source (Great Britain). The experiment has shown the capability of these devices to work at a pulsed neutron source for beam monitoring purposes. Other interesting possible applications are also suggested.

  5. 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.

  6. Neutron instrumentation for biology

    SciTech Connect

    Mason, S.A.

    1994-12-31

    In the October 1994 round of proposals at the ILL, the external biology review sub- committee was asked to allocate neutron beam time to a wide range of experiments, on almost half the total number of scheduled neutron instruments: on 3 diffractometers, on 3 small angle scattering instruments, and on some 6 inelastic scattering spectrometers. In the 3.5 years since the temporary reactor shutdown, the ILL`s management structure has been optimized, budgets and staff have been trimmed, the ILL reactor has been re-built, and many of the instruments up-graded, many powerful (mainly Unix) workstations have been introduced, and the neighboring European Synchrotron Radiation Facility has established itself as the leading synchrotron radiation source and has started its official user program. The ILL reactor remains the world`s most intense dedicated neutron source. In this challenging context, it is of interest to review briefly the park of ILL instruments used to study the structure and energetics of small and large biological systems. A brief summary will be made of each class of experiments actually proposed in the latest ILL proposal round.

  7. NEUTRONIC REACTOR CORE INSTRUMENT

    DOEpatents

    Mims, L.S.

    1961-08-22

    A multi-purpose instrument for measuring neutron flux, coolant flow rate, and coolant temperature in a nuclear reactor is described. The device consists essentially of a hollow thimble containing a heat conducting element protruding from the inner wall, the element containing on its innermost end an amount of fissionsble materinl to function as a heat source when subjected to neutron flux irradiation. Thermocouple type temperature sensing means are placed on the heat conducting element adjacent the fissionable material and at a point spaced therefrom, and at a point on the thimble which is in contact with the coolant fluid. The temperature differentials measured between the thermocouples are determinative of the neutron flux, coolant flow, and temperature being measured. The device may be utilized as a probe or may be incorporated in a reactor core. (AE C)

  8. INSTRUMENTS AND METHODS OF INVESTIGATION: Giant pulses of thermal neutrons in large accelerator beam dumps. Possibilities for experiments

    NASA Astrophysics Data System (ADS)

    Stavissky, Yurii Ya

    2006-12-01

    A short review is presented of the development in Russia of intense pulsed neutron sources for physical research — the pulsating fast reactors IBR-1, IBR-30, IBR-2 (Joint Institute for Nuclear Research, Dubna), and the neutron-radiation complex of the Moscow meson factory — the 'Troitsk Trinity' (RAS Institute for Nuclear Research, Troitsk, Moscow region). The possibility of generating giant neutron pulses in beam dumps of superhigh energy accelerators is discussed. In particular, the possibility of producing giant pulsed thermal neutron fluxes in modified beam dumps of the large hadron collider (LHD) under construction at CERN is considered. It is shown that in the case of one-turn extraction ov 7-TeV protons accumulated in the LHC main rings on heavy targets with water or zirconium-hydride moderators placed in the front part of the LHC graphite beam-dump blocks, every 10 hours relatively short (from ~100 µs) thermal neutron pulses with a peak flux density of up to ~1020 neutrons cm-2 s-1 may be produced. The possibility of applying such neutron pulses in physical research is discussed.

  9. New sources and instrumentation for neutron science

    NASA Astrophysics Data System (ADS)

    Gil, Alina

    2011-04-01

    Neutron-scattering research has a lot to do with our everyday lives. Things like medicine, food, electronics, cars and airplanes have all been improved by neutron-scattering research. Neutron research also helps scientists improve materials used in a multitude of different products, such as high-temperature superconductors, powerful lightweight magnets, stronger, lighter plastic products etc. Neutron scattering is one of the most effective ways to obtain information on both, the structure and the dynamics of condensed matter. Most of the world's neutron sources were built decades ago, and although the uses and demand for neutrons have increased throughout the years, few new sources have been built. The new construction, accelerator-based neutron source, the spallation source will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. In this paper it will be described what neutrons are and what unique properties make them useful for science, how spallation source is designed to produce neutron beams and the experimental instruments that will use those beams. Finally, it will be described how past neutron research has affected our everyday lives and what we might expect from the most exciting future applications.

  10. Neutron Instruments Added at Oak Ridge

    SciTech Connect

    Ekkebus, Allen E

    2011-01-01

    The neutron scattering facilities at Oak Ridge National Laboratory continue their development as new instruments are commissioned and join the user program at the Spallation Neutron Source and High Flux Isotope Reactor. More than 640 proposals were received for beam time during the January-May 2011 period on SNS and HFIR instruments with about half either being accepted or identified as alternates. The proposal call for the period June-December 2011, announced at http://neutrons.ornl.gov, will close February 23, 2011.

  11. 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.

  12. 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)

  13. Beam Instrument Development System

    SciTech Connect

    DOOLITTLE, LAWRENCE; HUANG, GANG; DU, QIANG; SERRANO, CARLOS

    2016-01-08

    Beam Instrumentation Development System (BIDS) is a collection of common support libraries and modules developed during a series of Low-Level Radio Frequency (LLRF) control and timing/synchronization projects. BIDS includes a collection of Hardware Description Language (HDL) libraries and software libraries. The BIDS can be used for the development of any FPGA-based system, such as LLRF controllers. HDL code in this library is generic and supports common Digital Signal Processing (DSP) functions, FPGA-specific drivers (high-speed serial link wrappers, clock generation, etc.), ADC/DAC drivers, Ethernet MAC implementation, etc.

  14. 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.

  15. Development of pulsed neutron uranium logging instrument.

    PubMed

    Wang, Xin-guang; Liu, Dan; Zhang, Feng

    2015-03-01

    This article introduces a development of pulsed neutron uranium logging instrument. By analyzing the temporal distribution of epithermal neutrons generated from the thermal fission of (235)U, we propose a new method with a uranium-bearing index to calculate the uranium content in the formation. An instrument employing a D-T neutron generator and two epithermal neutron detectors has been developed. The logging response is studied using Monte Carlo simulation and experiments in calibration wells. The simulation and experimental results show that the uranium-bearing index is linearly correlated with the uranium content, and the porosity and thermal neutron lifetime of the formation can be acquired simultaneously.

  16. Development of pulsed neutron uranium logging instrument

    SciTech Connect

    Wang, Xin-guang; Liu, Dan; Zhang, Feng

    2015-03-15

    This article introduces a development of pulsed neutron uranium logging instrument. By analyzing the temporal distribution of epithermal neutrons generated from the thermal fission of {sup 235}U, we propose a new method with a uranium-bearing index to calculate the uranium content in the formation. An instrument employing a D-T neutron generator and two epithermal neutron detectors has been developed. The logging response is studied using Monte Carlo simulation and experiments in calibration wells. The simulation and experimental results show that the uranium-bearing index is linearly correlated with the uranium content, and the porosity and thermal neutron lifetime of the formation can be acquired simultaneously.

  17. Intercomparison of radiation protection instrumentation in a pulsed neutron field

    NASA Astrophysics Data System (ADS)

    Caresana, M.; Denker, A.; Esposito, A.; Ferrarini, M.; Golnik, N.; Hohmann, E.; Leuschner, A.; Luszik-Bhadra, M.; Manessi, G.; Mayer, S.; Ott, K.; Röhrich, J.; Silari, M.; Trompier, F.; Volnhals, M.; Wielunski, M.

    2014-02-01

    In the framework of the EURADOS working group 11, an intercomparison of active neutron survey meters was performed in a pulsed neutron field (PNF). The aim of the exercise was to evaluate the performances of various neutron instruments, including commercially available rem-counters, personal dosemeters and instrument prototypes. The measurements took place at the cyclotron of the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. The cyclotron is routinely used for proton therapy of ocular tumours, but an experimental area is also available. For the therapy the machine accelerates protons to 68 MeV. The interaction of the proton beam with a thick tungsten target produces a neutron field with energy up to about 60 MeV. One interesting feature of the cyclotron is that the beam can be delivered in bursts, with the possibility to modify in a simple and flexible way the burst length and the ion current. Through this possibility one can obtain radiation bursts of variable duration and intensity. All instruments were placed in a reference position and irradiated with neutrons delivered in bursts of different intensity. The analysis of the instrument response as a function of the burst charge (the total electric charge of the protons in the burst shot onto the tungsten target) permitted to assess for each device the dose underestimation due to the time structure of the radiation field. The personal neutron dosemeters were exposed on a standard PMMA slab phantom and the response linearity was evaluated.

  18. 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.

  19. Properties and uses of cold neutron beams

    SciTech Connect

    Clark, David D.

    1992-07-01

    Cold neutrons are conventionally defined as those with energy below 0.005 eV; the corresponding velocity and wavelength arc 980 m/s and 4 angstroms. The first extensive use of cold neutrons was in the 1960's by condensed matter physicists for investigations of spatial structure and internal dynamics of solids and liquids. Different experiments place different requirements on neutron beams, but it is usually advantageous to eliminate the faster neutrons and the gamma rays that are present in normal reactor beams. Several types of filters that pass only the low-energy portion of an incident Maxwellian spectrum have been developed and will be discussed. Examples include single crystal quartz or bismuth (room temperature or cooled), polycrystalline beryllium, and neutron guides. For any of these shifting the incident neutrons to a lower energy spectrum by use of a cold moderator leads to large increases in the intensity of cold neutrons. The properties of the beams resulting from the particular combination of a cold moderator and a neutron guide will be discussed. These include the changes in beam intensity and spectral shape as warm neutrons in a typical reactor spectrum first interact with a cold moderator and then pass through a straight or curved neutron guide. The spatial and angular distribution of the neutrons at the exit of the guide will be described. One further important effect for cold neutron beam experiments involving nuclear reactions is the increase in reaction rates because of the usual 1/v dependence of reaction cross sections and another is the considerable simplification with cold neutrons in the problems of collimating, shielding, and stopping the beam. The resulting benefits for studies of nuclear energy levels by neutron capture gamma-ray and conversion electron experiments and for the analysis of materials by PGNAA will be discussed. Neutron depth profiling is also improved with cold neutrons. (author)

  20. The neutron instrument simulation package, NISP

    NASA Astrophysics Data System (ADS)

    Seeger, Philip A.; Daemen, Luke L.

    2004-10-01

    The Neutron Instrument Simulation Package (NISP) performs complete source-to-detector simulations of neutron instruments, including neutrons that do not follow the expected path. The original user interface (MC_Web) is a web-based application, http://strider.lansce.lanl.gov/NISP/Welcome.html. This report describes in detail the newer stand-alone Windows version, NISP_Win. Instruments are assembled from menu-selected elements, including neutron sources, collimation and transport elements, samples, analyzers, and detectors. Magnetic field regions may also be specified for the propagation of polarized neutrons including spin precession. Either interface writes a geometry file that is used as input to the Monte Carlo engine (MC_Run) in the user's computer. Both the interface and the engine rely on a subroutine library, MCLIB. The package is completely open source. New features include capillary optics, temperature dependence of Al and Be, revised source files for ISIS, and visualization of neutron trajectories at run time. Also, a single-crystal sample type has been successfully imported from McStas (with more generalized geometry), demonstrating the capability of including algorithms from other sources, and NISP_Win may render the instrument in a virtual reality file. Results are shown for two instruments under development.

  1. Intermediate energy neutron beams from the MURR.

    PubMed

    Brugger, R M; Herleth, W H

    1990-01-01

    Several reactors in the United States are potential candidates to deliver 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.

  2. 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.

  3. Improvements in neutron beam applications by using capillary neutron optics

    NASA Astrophysics Data System (ADS)

    Downing, Robert G.; Xiao, Qi-Fan; Sharov, V. A.; Ponomarev, Igor Y.; Ullrich, Johannes B.; Gibson, David M.; Chen-Mayer, Huaiyu H.; Mildner, David F. R.; Lamaze, G. P.

    1997-02-01

    Capillary neutron optics improve the capabilities of neutron beam techniques such as neutron depth profiling and prompt gamma activation analysis. Millions of glass capillaries are configured to capture and guide low-energy neutrons by grazing total reflection from the smooth inner surface of the hollow channels. By precise orientation of the capillaries, beams of neutrons are readily collimated with good angular control or can be finely focused - as required by the application. In addition, the optics can improve the signal-to-noise ratio by diverting a neutron beam to a convenient off-axis direction, thereby circumventing interferences from gamma rays and fast neutrons characteristic of simple aperture collimation. The focused intensity of neutrons obtained in an area of 0.03 mm2 may be increased up to a hundred times over that previously available for NDP or PGAA techniques. Furthermore, the spatial resolution can be improved by up to 100 times. Consequently, small samples, or small volumes within larger samples, may be better and more rapidly investigated with neutron probe techniques. We report on developments in the application of capillary neutron optics.

  4. 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.

  5. Monte Carlo simulation of neutron scattering instruments

    SciTech Connect

    Seeger, P.A.

    1995-12-31

    A library of Monte Carlo subroutines has been developed for the purpose of design of neutron scattering instruments. Using small-angle scattering as an example, the philosophy and structure of the library are described and the programs are used to compare instruments at continuous wave (CW) and long-pulse spallation source (LPSS) neutron facilities. The Monte Carlo results give a count-rate gain of a factor between 2 and 4 using time-of-flight analysis. This is comparable to scaling arguments based on the ratio of wavelength bandwidth to resolution width.

  6. Neutron beams from protons on beryllium.

    PubMed

    Bewley, D K; Meulders, J P; Octave-Prignot, M; Page, B C

    1980-09-01

    Measurements of dose rate and penetration in water have been made for neutron beams produced by 30--75 MeV protons on beryllium. The effects of Polythene filters added on the target side of the collimator have also been studied. A neutron beam comparable with a photon beam from a 4--8 MeV linear accelerator can be produced with p/Be neutrons plus 5 cm Polythene filtrations, with protons in the range 50--75 MeV. This is a more economical method than use of the d/Be reaction.

  7. IB: a Monte Carlo Simulation Tool for Neutron Scattering Instrument Design under Parallel Virtual Machine

    SciTech Connect

    Zhao, Jinkui

    2011-01-01

    IB is a Monte Carlo simulation tool for aiding neutron scattering instrument designs. It is written in C++ and implemented under Parallel Virtual Machine. The program has a few basic components, or modules, that can be used to build a virtual neutron scattering instrument. More complex components, such as neutron guides and multichannel beam benders, can be constructed using the grouping technique unique to IB. Users can specify a collection of modules as a group. For example, a neutron guide can be constructed by grouping four neutron mirrors together that make up the four sides of the guide. IB s simulation engine ensures that neutrons entering a group will be properly operated upon by all members of the group. For simulations that require higher computer speed, the program can be run in parallel mode under the PVM architecture. Initially, the program was written for designing instruments on pulsed neutron sources, it has since been used to simulate reactor based instruments as well.

  8. Evolutionary programming for neutron instrument optimisation

    NASA Astrophysics Data System (ADS)

    Bentley, Phillip M.; Pappas, Catherine; Habicht, Klaus; Lelièvre-Berna, Eddy

    2006-11-01

    Virtual instruments based on Monte-Carlo techniques are now integral part of novel instrumentation development and the existing codes (McSTAS and Vitess) are extensively used to define and optimise novel instrumental concepts. Neutron spectrometers, however, involve a large number of parameters and their optimisation is often a complex and tedious procedure. Artificial intelligence algorithms are proving increasingly useful in such situations. Here, we present an automatic, reliable and scalable numerical optimisation concept based on the canonical genetic algorithm (GA). The algorithm was used to optimise the 3D magnetic field profile of the NSE spectrometer SPAN, at the HMI. We discuss the potential of the GA which combined with the existing Monte-Carlo codes (Vitess, McSTAS, etc.) leads to a very powerful tool for automated global optimisation of a general neutron scattering instrument, avoiding local optimum configurations.

  9. 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.

  10. New Very Small Angle Neutron Scattering (VSANS) Instrument

    NASA Astrophysics Data System (ADS)

    Van Every, E.; Deyhim, A.; Kulesza, J.

    2016-09-01

    The design of a new Very Small Angle Neutron Scattering (VSANS) Instrument for use in National Institute of Standards And Technology (NIST) will be discussed. This instrument is similar to a shorter instrument we designed and delivered to ANSTO in Australia called the Bilby SANS instrument. The NIST VSANS and the ANSTO Bilby SANS instruments have very similar dimensions for length and diameter and have similar requirements for internal detector motion, top access port, walkway supports, and ports; however, the Bilby SANS instrument vacuum requirement was lower (7.5×10-5 Torr) and the entire (60,000 pound) vessel was required to move 1.5 meters on external rails with a repeatability of 100 um, which ADC achieved. The NIST VSANS length is 24 meter, internal diameter 2.3 meter with three internal carriages. The NIST VSANS instrument, which covers the usual SANS range will also allow configuration to cover the range between q ∼⃒ 10-4 A-1 to 10-3 A-1 with a sample beam current of (104 neutrons/s). The key requirements are a second position-sensitive detector system having a 1 mm pixel size and a longer sample-detector flight path of 20 m (i.e., a 40 m instrument).

  11. Survey of beam instrumentation used in SLC

    SciTech Connect

    Ecklund, S.D.

    1991-03-01

    A survey of beam instruments used at SLAC in the SLC machine is presented. The basic utility and operation of each device is briefly described. The various beam instruments used at the Stanford Linear Collider (SLC), can be classified by the function they perform. Beam intensity, position and size are typical of the parameters of beam which are measured. Each type of parameter is important for adjusting or tuning the machine in order to achieve optimum performance. 39 refs.

  12. BEAM INSTRUMENTATION FOR HIGH POWER HADRON BEAMS

    SciTech Connect

    Aleksandrov, Alexander V

    2013-01-01

    This presentation will describe developments in the beam diagnostics which support the understanding and operation of high power hadron accelerators. These include the measurement of large dynamic range transverse and longitudinal beam profiles, beam loss detection, and non-interceptive diagnostics.

  13. 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.

  14. 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

  15. Progress in KEKB beam instrumentation systems

    NASA Astrophysics Data System (ADS)

    Arinaga, Mitsuhiro; Flanagan, John W.; Fukuma, Hitoshi; Furuya, Takaaki; Hiramatsu, Shigenori; Ikeda, Hitomi; Ishii, Hitoshi; Kikutani, Eiji; Mitsuhashi, Toshiyuki; Mori, Kenji; Tejima, Masaki; Tobiyama, Makoto

    2013-03-01

    The paper describes several topics relating to the beam instrumentation systems at the KEKB B-factory (KEKB) from 2003 to the end of its operation. It covers 1) measurement of the tilt angle of a bunch caused by a crab cavity, 2) a diagnostic system for beam aborts, 3) bunch feedback and related systems, and 4) progress in the beam position monitor system.

  16. 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.

  17. Neutron scattering instrumentation for biology at spallation neutron sources

    SciTech Connect

    Pynn, R.

    1994-12-31

    Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. In fact, the current generation of pulsed spallation neutron sources, such as LANSCE at Los Alamos and ISIS in the United Kingdom, has demonstrated a capability for small angle scattering (SANS) - a typical cold- neutron application - that was not anticipated five years ago. Although no one has yet built a Laue diffractometer at a pulsed spallation source, calculations show that such an instrument would provide an exceptional capability for protein crystallography at one of the existing high-power spoliation sources. Even more exciting is the prospect of installing such spectrometers either at a next-generation, short-pulse spallation source or at a long-pulse spallation source. A recent Los Alamos study has shown that a one-megawatt, short-pulse source, which is an order of magnitude more powerful than LANSCE, could be built with today`s technology. In Europe, a preconceptual design study for a five-megawatt source is under way. Although such short-pulse sources are likely to be the wave of the future, they may not be necessary for some applications - such as Laue diffraction - which can be performed very well at a long-pulse spoliation source. Recently, it has been argued by Mezei that a facility that combines a short-pulse spallation source similar to LANSCE, with a one-megawatt, long-pulse spallation source would provide a cost-effective solution to the global shortage of neutrons for research. The basis for this assertion as well as the performance of some existing neutron spectrometers at short-pulse sources will be examined in this presentation.

  18. New beam instrumentation in the AGS Booster

    SciTech Connect

    Witkover, R.L.

    1991-01-01

    The AGS Booster was designed to accelerate beams from 2{times}10{sup 10} polarized protons to 1.5{times}10{sup 13} protons and heavy ions through Au{sup +33}. The range of beam parameters and the high vacuum, and radiation environment presented challenges for the beam instrumentation. Some interesting beam monitors in the Booster and transport lines, will be described. Where available, results will be presented. 21 refs., 7 figs.

  19. 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

  20. LEDA BEAM DIAGNOSTICS INSTRUMENTATION: BEAM POSITION MONITORS

    SciTech Connect

    D. BARR; ET AL

    2000-05-01

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7-MeV and current of 100-mA operating in either a pulsed or cw mode. Of key importance to the commissioning and operations effort is the Beam Position Monitor system (BPM). The LEDA BPM system uses five micro-stripline beam position monitors processed by log ratio processing electronics with data acquisition via a series of custom TMS32OC40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of the system, the log ratio processing, and the system calibration technique. This paper will also cover the DSP system operations and their interaction with the main accelerator control system.

  1. New sources and instrumentation for neutrons in biology

    PubMed Central

    Teixeira, S.C.M.; Ankner, J.; Bellissent-Funel, M.C.; Bewley, R.; Blakeley, M.P.; Coates, L.; Dahint, R.; Dalgliesh, R.; Dencher, N.; Dhont, J.; Fischer, P.; Forsyth, V.T.; Fragneto, G.; Frick, B.; Geue, T.; Gilles, R.; Gutberlet, T.; Haertlein, M.; Hauß, T.; Häußler, W.; Heller, W.T.; Herwig, K.; Holderer, O.; Juranyi, F.; Kampmann, R.; Knott, R.; Kohlbrecher, J.; Kreuger, S.; Langan, P.; Lechner, R.; Lynn, G.; Majkrzak, C.; May, R.; Meilleur, F.; Mo, Y.; Mortensen, K.; Myles, D.A.A.; Natali, F.; Neylon, C.; Niimura, N.; Ollivier, J.; Ostermann, A.; Peters, J.; Pieper, J.; Rühm, A.; Schwahn, D.; Shibata, K.; Soper, A.K.; Straessle, T.; Suzuki, U.-i.; Tanaka, I.; Tehei, M.; Timmins, P.; Torikai, N.; Unruh, T.; Urban, V.; Vavrin, R.; Weiss, K.; Zaccai, G.

    2008-01-01

    Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed. PMID:19132140

  2. New sources and instrumentation for neutrons in biology

    NASA Astrophysics Data System (ADS)

    Teixeira, S. C. M.; Zaccai, G.; Ankner, J.; Bellissent-Funel, M. C.; Bewley, R.; Blakeley, M. P.; Callow, P.; Coates, L.; Dahint, R.; Dalgliesh, R.; Dencher, N. A.; Forsyth, V. T.; Fragneto, G.; Frick, B.; Gilles, R.; Gutberlet, T.; Haertlein, M.; Hauß, T.; Häußler, W.; Heller, W. T.; Herwig, K.; Holderer, O.; Juranyi, F.; Kampmann, R.; Knott, R.; Krueger, S.; Langan, P.; Lechner, R. E.; Lynn, G.; Majkrzak, C.; May, R. P.; Meilleur, F.; Mo, Y.; Mortensen, K.; Myles, D. A. A.; Natali, F.; Neylon, C.; Niimura, N.; Ollivier, J.; Ostermann, A.; Peters, J.; Pieper, J.; Rühm, A.; Schwahn, D.; Shibata, K.; Soper, A. K.; Strässle, Th.; Suzuki, J.; Tanaka, I.; Tehei, M.; Timmins, P.; Torikai, N.; Unruh, T.; Urban, V.; Vavrin, R.; Weiss, K.

    2008-04-01

    Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.

  3. LEDA beam diagnostics instrumentation: Beam current measurement

    NASA Astrophysics Data System (ADS)

    Barr, D.; Day, L.; Gilpatrick, J. D.; Kasemir, K.-U.; Martinez, D.; Power, J. F.; Shurter, R.; Stettler, M.

    2000-11-01

    The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7 MeV and current of 100 mA operating in either a pulsed or cw mode. Two types of current measurements are used. The first is an AC or pulsed-current measurement which uses three LANL built toroids. They are placed in the beamline in such a way as to measure important transmission parameters and act as a differential current-loss machine protection system. The second system is a DC current measurement used to measure cw beam characteristics and uses toroids from Bergoz Inc. There are two of these systems, so they can also be used for transmission measurements. The AC system uses custom processing electronics whereas the DC system uses a modified Bergoz® electronics system. Both systems feature data acquisition via a series of custom TMS320C40 Digital Signal Processing (DSP) boards. Of special interest to this paper is the operation of these systems, the calibration technique, the differential current loss measurements and fast-protection processing, current droop characteristics for the AC system, and existing system noise levels. This paper will also cover the DSP system operations and their interaction with the main accelerator control system.

  4. Status of the Neutron Imaging and Diffraction Instrument IMAT

    NASA Astrophysics Data System (ADS)

    Kockelmann, Winfried; Burca, Genoveva; Kelleher, Joe F.; Kabra, Saurabh; Zhang, Shu-Yan; Rhodes, Nigel J.; Schooneveld, Erik M.; Sykora, Jeff; Pooley, Daniel E.; Nightingale, Jim B.; Aliotta, Francesco; Ponterio, Rosa C.; Salvato, Gabriele; Tresoldi, Dario; Vasi, Cirino; McPhate, Jason B.; Tremsin, Anton S.

    A cold neutron imaging and diffraction instrument, IMAT, is currently being constructed at the ISIS second target station. IMAT will capitalize on time-of-flight transmission and diffraction techniques available at a pulsed neutron source. Analytical techniques will include neutron radiography, neutron tomography, energy-selective neutron imaging, and spatially resolved diffraction scans for residual strain and texture determination. Commissioning of the instrument will start in 2015, with time-resolving imaging detectors and two diffraction detector prototype modules. IMAT will be operated as a user facility for material science applications and will be open for developments of time-of-flight imaging methods.

  5. LUPIN, a new instrument for pulsed neutron fields

    NASA Astrophysics Data System (ADS)

    Caresana, M.; Ferrarini, M.; Manessi, G. P.; Silari, M.; Varoli, V.

    2013-06-01

    A number of studies focused in the last decades on the development of survey meters to be used in pulsed radiation fields. This is a topic attracting widespread interest for applications such as radiation protection and beam diagnostics in accelerators. This paper describes a new instrument specifically conceived for applications in pulsed neutron fields (PNF). The detector, called LUPIN, is a rem counter type instrument consisting of a 3He proportional counter placed inside a spherical moderator. It works in current mode with a front-end electronics consisting of a current-voltage logarithmic amplifier, whose output signal is acquired with an ADC and processed on a PC. This alternative signal processing allows the instrument to be used in PNF without being affected by saturation effects. Moreover, it has a measurement capability ranging over many orders of burst intensity. Despite the fact that it works in current mode, it can measure a single neutron interaction. The LUPIN was first calibrated in CERN's calibration laboratory with a PuBe source. Measurements were carried out under various experimental conditions at the Helmholtz-Zentrum in Berlin, in the stray field at various locations of the CERN Proton Synchrotron complex and around a radiotherapy linear accelerator at the S. Raffaele hospital in Milan. The detector can withstand single bursts with values of H*(10) up to 16 nSv/burst without showing any saturation effect. It efficiently works in pulsed stray fields, where a conventional rem-counter underestimates by a factor of 2. It is also able to reject the very intense and pulsed photon contribution that often accompanies the neutron field with good reliability.

  6. Measurement of neutron flux and beam divergence at the cold neutron guide system of the new Munich research reactor FRM-II

    NASA Astrophysics Data System (ADS)

    Zeitelhack, K.; Schanzer, C.; Kastenmüller, A.; Röhrmoser, A.; Daniel, C.; Franke, J.; Gutsmiedl, E.; Kudryashov, V.; Maier, D.; Päthe, D.; Petry, W.; Schöffel, T.; Schreckenbach, K.; Urban, A.; Wildgruber, U.

    2006-05-01

    A sophisticated neutron guide system has been installed at the new Munich neutron source FRM-II to transport neutrons from the D 2 cold neutron source to several instruments, which are situated in a separate neutron guide hall. The guide system takes advantage of supermirror coatings and includes a worldwide unique "twisted" guide for a desired phase space transformation of the neutron beam. During the initial reactor commissioning in summer 2004, the integral and differential neutron flux as well as the distribution of beam divergence at the exit of two representative and the twisted neutron guide were measured using time-of-flight spectroscopy and gold-foil activation. The experimental results can be compared to extensive simulation calculations based on MCNP and McStas. The investigated guides fulfill the expectations of providing high neutron fluxes and reveal good quality with respect to the reflective coatings and the installation precision.

  7. BL3: A Next Generation Beam Neutron Lifetime Experiment

    NASA Astrophysics Data System (ADS)

    Wietfeldt, F. E.; Fomin, N.; Greene, G. L.; Snow, W. M.; Liu, C.-Y.; Crawford, C. B.; Korsch, W.; Plaster, B.; Jones, G. L.; Collett, B.; Dewey, M. S.

    2016-09-01

    BL3 (Beam Lifetime 3) is a proposed next generation neutron lifetime experiment using the beam method. It continues a program, spanning more than three decades, of experiments at the ILL (France) and the NIST Center for Neutron Research that achieved the most precise beam method neutron lifetime measurements to date. A collimated cold neutron beam passes through a quasi-Penning trap where recoil protons from neutron decay are trapped. Periodically the trap is opened and these protons follow a bend in the magnetic field to a silicon detector. The same neutron beam passes through a thin-foil neutron counter that measures the neutron density. The ratio of neutron and proton count rates, along with efficiency factors, gives the neutron lifetime. The main goal of BL3 is to thoroughly investigate and test systematic effects in the beam method in an effort to address the current 4 σ discrepancy between the beam and bottle methods. It will employ a much larger, higher flux neutron beam, a large area position-sensitive proton detector, and an improved magnet design, with a proton trapping rate 100 times higher than past experiments. National Science Foundation, U.S. Dept. of Energy Office of Science.

  8. 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.

  9. Beam instrumentation for the Tevatron Collider

    SciTech Connect

    Moore, Ronald S.; Jansson, Andreas; Shiltsev, Vladimir; /Fermilab

    2009-10-01

    The Tevatron in Collider Run II (2001-present) is operating with six times more bunches and many times higher beam intensities and luminosities than in Run I (1992-1995). Beam diagnostics were crucial for the machine start-up and the never-ending luminosity upgrade campaign. We present the overall picture of the Tevatron diagnostics development for Run II, outline machine needs for new instrumentation, present several notable examples that led to Tevatron performance improvements, and discuss the lessons for future colliders.

  10. Grazing incidence neutron spin echo spectroscopy: instrumentation aspects and scientific opportunities

    NASA Astrophysics Data System (ADS)

    Holderer, O.; Frielinghaus, H.; Wellert, S.; Lipfert, F.; Monkenbusch, M.; von Klitzing, R.; Richter, D.

    2014-07-01

    Grazing Incidence Neutron Spin Echo Spectroscopy (GINSES) opens new possibilities for observing the thermally driven dynamics of macromolecules close to a rigid interface. The information about the dynamics can be retrieved as a function of scattering depth of the evanescent neutron wave, on the length scale in the range of some 10-100 nm. Using a classical neutron spin echo spectrometer with a laterally collimated beam, dynamics can be measured in grazing incidence geometry. We show examples of how the interface modifies the dynamics of microemulsions, membranes and microgels. Instrumental details and possible improvements for this technique will be presented. The key issue is the low intensity for dynamics measurements with an evanescent neutron wave. Conceptual questions how a specialised instrument could improve the experimental technique will be discussed.

  11. Instrumental Neutron Activation Analysis and Multivariate Statistics for Pottery Provenance

    NASA Astrophysics Data System (ADS)

    Glascock, M. D.; Neff, H.; Vaughn, K. J.

    2004-06-01

    The application of instrumental neutron activation analysis and multivariate statistics to archaeological studies of ceramics and clays is described. A small pottery data set from the Nasca culture in southern Peru is presented for illustration.

  12. 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.

  13. Quantifying the information measured by neutron scattering instruments

    SciTech Connect

    Johnson, M.W.

    1997-09-01

    The concept of the information content of a scientific measurement is introduced, and a theory is presented which enables the information that may be obtained by a neutron scattering instrument to be calculated. When combined with the time taken to perform the measurement the bandwidth of the instrument is obtained. This bandwidth is effectively a figure of merit which is of use in three respects: in the design of neutron instrumentation, the optimisation of measurements, and in the comparison of one instrument with another.

  14. Progress toward a new beam measurement of the neutron lifetime

    NASA Astrophysics Data System (ADS)

    Hoogerheide, Shannon Fogwell; BL2 Collaboration

    2017-01-01

    Neutron beta decay is the simplest example of nuclear beta decay. A precise value of the neutron lifetime is important for consistency tests of the Standard Model and Big Bang Nucleosynthesis models. The beam neutron lifetime method requires the absolute counting of the decay protons in a neutron beam of precisely known flux. Recent work has resulted in improvements in both the neutron and proton detection systems that should permit a significant reduction in systematic uncertainties. A new measurement of the neutron lifetime using the beam method is underway at the National Institute of Standards and Technology Center for Neutron Research. The projected uncertainty of this new measurement is 1 s. An overview of the measurement, its current status, and the technical improvements will be discussed.

  15. Progress toward a new beam measurement of the neutron lifetime

    NASA Astrophysics Data System (ADS)

    Hoogerheide, Shannon Fogwell

    2016-09-01

    Neutron beta decay is the simplest example of nuclear beta decay. A precise value of the neutron lifetime is important for consistency tests of the Standard Model and Big Bang Nucleosysnthesis models. The beam neutron lifetime method requires the absolute counting of the decay protons in a neutron beam of precisely known flux. Recent work has resulted in improvements in both the neutron and proton detection systems that should permit a significant reduction in systematic uncertainties. A new measurement of the neutron lifetime using the beam method will be performed at the National Institute of Standards and Technology Center for Neutron Research. The projected uncertainty of this new measurement is 1 s. An overview of the measurement and the technical improvements will be discussed.

  16. Neutron Scattering Collimation Wheel Instrument for Imaging Research

    NASA Astrophysics Data System (ADS)

    Van Every, E.; Deyhim, A.

    2016-09-01

    The design of a state-of-the-art selector wheel instrument to support the area of neutron imaging research (neutron radiography/ tomography) is discussed. The selector wheel is installed on the DINGO Radiography instrument at the Bragg Institute HB2 beamline at ANSTO in Sidney Aus. The selector wheel consists of a single axis drum filled with a wax/steel shielding mixture and six square cutouts for neutron optics and a larger solid shielding sector to act as a shutter. This paper focuses on the details of design and shielding of the selector wheel.

  17. Data acquisition system for the neutron scattering instruments at the intense pulsed neutron source

    SciTech Connect

    Crawford, R.K.; Daly, R.T.; Haumann, J.R.; Hitterman, R.L.; Morgan, C.B.; Ostrowski, G.E.; Worlton, T.G.

    1981-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a major new user-oriented facility which is now coming on line for basic research in neutron scattering and neutron radiation damage. This paper describes the data-acquisition system which will handle data acquisition and instrument control for the time-of-flight neutron-scattering instruments at IPNS. This discussion covers the scientific and operational requirements for this system, and the system architecture that was chosen to satisfy these requirements. It also provides an overview of the current system implementation including brief descriptions of the hardware and software which have been developed.

  18. Planetary Geochemistry Using Active Neutron and Gamma Ray Instrumentation

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Schweitzer, J.; Starr, R.; Trombka, J.

    2010-01-01

    The Pulsed Neutron Generator-Gamma Ray And Neutron Detector (PNG-GRAND) experiment is an innovative application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth, The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring the PNG-GRAND instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asterOIds, comets and the satellites of the outer planets, Gamma-Ray Spectrometers have been incorporated into numerous orbital planetary science missions and, especially in the case of Mars Odyssey, have contributed detailed maps of the elemental composition over the entire surface of Mars, Neutron detectors have also been placed onboard orbital missions such as the Lunar Reconnaissance Orbiter and Lunar Prospector to measure the hydrogen content of the surface of the moon, The DAN in situ experiment on the Mars Science Laboratory not only includes neutron detectors, but also has its own neutron generator, However, no one has ever combined the three into one instrument PNG-GRAND combines a pulsed neutron generator (PNG) with gamma ray and neutron detectors to produce a landed instrument that can determine subsurface elemental composition without drilling. We are testing PNG-GRAND at a unique outdoor neutron instrumentation test facility recently constructed at NASA/GSFC that consists of a 2 m x 2 m x 1 m granite structure in an empty field, We will present data from the operation of PNG-GRAND in various experimental configurations on a known sample in a geometry that is identical to that which can be achieved on a planetary surface. We will also compare the material composition results inferred from our experiments to both an independent laboratory elemental composition analysis and MCNPX computer modeling results,

  19. A complex of complementary pulsed neutron sources, neutron and radiographic nano-diagnostic instruments at the Institute for Nuclear Research RAS

    NASA Astrophysics Data System (ADS)

    Koptelov, E. A.; Ryabov, Yu V.; Alekseev, A. A.; Sidorkin, S. F.; Grachev, M. I.; Fedchenko, V. A.; Sadykov, R. A.; Lebed, Yu B.; Litvin, V. S.; Kuznetsov, S. P.; Clementyev, E. S.; Alekseev, P. A.; Trunov, V. A.; Bulkin, A. P.; Ulianov, V. A.; Axenov, S. N.

    2011-04-01

    A new large-scale research center for nano diagnostics and neutron and X-Ray studies of nanomaterials is briefly described. This center at the Institute for Nuclear Research of the Russian Academy of Sciences (INR RAS) is based on three specially designed spallation neutron sources driven by primary proton beams. Similar research centers on the basis of the high flux spallation neutron sources are created in the USA, Japan, Great Britain, Switzerland and will be build in China and the EU (Sweden). We discuss neutron and X-Ray instrumentation at the INR RAS and the corresponding domains of research of various materials including nano-systems.

  20. Instrumental Asymmetry Reduction in Polarized Electron Beams

    NASA Astrophysics Data System (ADS)

    Fabrikant, M. I.; Trantham, K. W.; Gay, T. J.

    2008-05-01

    We report progress in the reduction of instrumental asymmetries (IAs) related to the photoemission of polarized electrons from GaAs caused by circularly-polarized diode laser beams [1]. Such asymmetries can mask true helicity-dependent interactions between the emitted electrons and chiral targets. Minimization of laser intensity IAs is achieved by chopping two spatially separated light beams with orthogonal polarizations which are recombined and passed through a quarter-wave plate to yield a single beam with rapidly flipping helicity. We have demonstrated the ability to reduce intensity IAs of the laser beam itself to less than 2 x 10-6 [2]. We have also investigated the IAs of the photemission current from the GaAs. At present, we are able to reduce the photoemission asymmetry to values that are comparable to the laser intensity asymmetry. Implications for experiments measuring effects due to electron circular dichroism [3] will be discussed. [1]Trantham K.W. et al J. Phys. B. 28 L543 (1995) [2] Fabrikant M.I. et al submitted to Appl. Opt. [3] Mayer S., Kessler J. Phys. Rev. Lett. 74, 4803 (1995) Funding for this project was provided by Undergraduate Creative Activities and Research Experiences (UCARE) and the National Science Foundation (PHY-0653379).

  1. Modularized Parallel Neutron Instrument Simulation on the TeraGrid

    SciTech Connect

    Chen, Meili; Cobb, John W; Hagen, Mark E; Miller, Stephen D; Lynch, Vickie E

    2007-01-01

    In order to build a bridge between the TeraGrid (TG), a national scale cyberinfrastructure resource, and neutron science, the Neutron Science TeraGrid Gateway (NSTG) is focused on introducing productive HPC usage to the neutron science community, primarily the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). Monte Carlo simulations are used as a powerful tool for instrument design and optimization at SNS. One of the successful efforts of a collaboration team composed of NSTG HPC experts and SNS instrument scientists is the development of a software facility named PSoNI, Parallelizing Simulations of Neutron Instruments. Parallelizing the traditional serial instrument simulation on TeraGrid resources, PSoNI quickly computes full instrument simulation at sufficient statistical levels in instrument de-sign. Upon SNS successful commissioning, to the end of 2007, three out of five commissioned instruments in SNS target station will be available for initial users. Advanced instrument study, proposal feasibility evalua-tion, and experiment planning are on the immediate schedule of SNS, which pose further requirements such as flexibility and high runtime efficiency on fast instrument simulation. PSoNI has been redesigned to meet the new challenges and a preliminary version is developed on TeraGrid. This paper explores the motivation and goals of the new design, and the improved software structure. Further, it describes the realized new fea-tures seen from MPI parallelized McStas running high resolution design simulations of the SEQUOIA and BSS instruments at SNS. A discussion regarding future work, which is targeted to do fast simulation for automated experiment adjustment and comparing models to data in analysis, is also presented.

  2. Neutron micro-beam design simulation by Monte Carlo

    NASA Astrophysics Data System (ADS)

    Pazirandeh, Ali; Taheri, Ali

    2007-09-01

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

  3. Development of neutron beam projects at the University of Texas TRIGA Mark II Reactor

    SciTech Connect

    Unlu, Kenan; Bauer, Thomas L.; Wehring, Bernard W.

    1992-07-01

    Recently, the UT-TRIGA research reactor was licensed and has become fully operational. This reactor, the first new US university reactor in 17 years, is the focus of a new reactor laboratory facility which is located on the Balcones Research Center at The University of Texas at Austin. The TRIGA Mark II reactor is licensed for 1.1 MW steady power operation, 3 dollar pulsing, and includes five beam ports. Various neutron beam-line projects have been assigned to each beam port. Neutron Depth Profiling (NDP) and the Texas Cold Neutron Source (TCNS) are close to completion and will be operational in the near future. The design of the NDP instrument has been completed, a target chamber has been built, and the thermal neutron collimator, detectors, data acquisition electronics, and data processing computers have been acquired. The target chamber accommodates wafers up to 12'' in diameter and provides remote positioning of these wafers. The design and construction of the TCNS has been completed. The TCNS consists of a moderator (mesitylene), a neon heat pipe, a cryogenic refrigerator, and neutron guide tubes. In addition, fission-fragment research (HIAWATHA), Neutron Capture Therapy, and Neutron Radiography are being pursued as projects for the other three beam ports. (author)

  4. A High Count Rate Neutron Beam Monitor for Neutron Scattering Facilities

    SciTech Connect

    Barnett, Amanda; Crow, Lowell; Diawara, Yacouba; Hayward, J P; Hayward, Jason P; Menhard, Kocsis; Sedov, Vladislav N; Funk, Loren L

    2013-01-01

    Abstract Beam monitors are an important diagnostic tool in neutron science facilities. Present beam monitors use either ionization chambers in integration mode, which are slow and have no timing information, or pulse counters which can easily be saturated by high beam intensities. At high flux neutron scattering facilities, neutron beam monitors with very low intrinsic efficiency (10-5) are presently selected to keep the counting rate within a feasible range, even when a higher efficiency would improve the counting statistics and yield a better measurement of the incident beam. In this work, we report on a high count rate neutron beam monitor. This beam monitor offers good timing with an intrinsic efficiency of 10-3 and a counting rate capability of over 1,000,000 cps without saturation.

  5. A New Cold Neutron Imaging Instrument at NIST

    NASA Astrophysics Data System (ADS)

    Hussey, D. S.; Brocker, C.; Cook, J. C.; Jacobson, D. L.; Gentile, T. R.; Chen, W. C.; Baltic, E.; Baxter, D. V.; Doskow, J.; Arif, M.

    The NIST neutron imaging program will build a new imaging instrument in the NCNR guide hall at the end of the neutron guide NG-6, beginning operation in summer of 2015. The NG-6 guide has a spectrum that is strongly peaked at a neutron wavelength of 0.5 nm, with a fluence rate of 2 × 109 cm-2 s-1 before a bismuth filter that is cooled by liquid nitrogen. The instrument will be developed in a phased manner and with an emphasis on maintaining a flexible space to conduct experiments and test new instrument concepts. In the initial phase of the instrument, the available space will permit a flight path of about 9 m, and will provide a platform for standard neutron radiography and tomography, wavelength selective imaging with a double crystal monochromator, and phase imaging based on a Talbot-Lau interferometer. The novel feature of the instrument will be the incorporation of Wolter optics to create a neutron microscope. Initially, prototype optics will be used in the microscope configuration to assess optic characteristics and image acquisition techniques. In the final form, the microscope will enable users to acquire images with ˜10 μm resolution 10-100x faster than current practice, and with a 10x magnifying optic to acquire images with ˜1 μm spatial resolution with image acquisition time similar to that for current images with ˜10 μm resolution.

  6. 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.

  7. Beam extraction and delivery at compact neutron sources

    NASA Astrophysics Data System (ADS)

    Mezei, F.

    2016-11-01

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

  8. Experiment Automation with a Robot Arm using the Liquids Reflectometer Instrument at the Spallation Neutron Source

    SciTech Connect

    Zolnierczuk, Piotr A; Vacaliuc, Bogdan; Sundaram, Madhan; Parizzi, Andre A; Halbert, Candice E; Hoffmann, Michael C; Greene, Gayle C; Browning, Jim; Ankner, John Francis

    2013-01-01

    The Liquids Reflectometer instrument installed at the Spallation Neutron Source (SNS) enables observations of chemical kinetics, solid-state reactions and phase-transitions of thin film materials at both solid and liquid surfaces. Effective measurement of these behaviors requires each sample to be calibrated dynamically using the neutron beam and the data acquisition system in a feedback loop. Since the SNS is an intense neutron source, the time needed to perform the measurement can be the same as the alignment process, leading to a labor-intensive operation that is exhausting to users. An update to the instrument control system, completed in March 2013, implemented the key features of automated sample alignment and robot-driven sample management, allowing for unattended operation over extended periods, lasting as long as 20 hours. We present a case study of the effort, detailing the mechanical, electrical and software modifications that were made as well as the lessons learned during the integration, verification and testing process.

  9. New developments in the McStas neutron instrument simulation package

    NASA Astrophysics Data System (ADS)

    Willendrup, P. K.; Knudsen, E. B.; Klinkby, E.; Nielsen, T.; Farhi, E.; Filges, U.; Lefmann, K.

    2014-07-01

    The McStas neutron ray-tracing software package is a versatile tool for building accurate simulators of neutron scattering instruments at reactors, short- and long-pulsed spallation sources such as the European Spallation Source. McStas is extensively used for design and optimization of instruments, virtual experiments, data analysis and user training. McStas was founded as a scientific, open-source collaborative code in 1997. This contribution presents the project at its current state and gives an overview of the main new developments in McStas 2.0 (December 2012) and McStas 2.1 (expected fall 2013), including many new components, component parameter uniformisation, partial loss of backward compatibility, updated source brilliance descriptions, developments toward new tools and user interfaces, web interfaces and a new method for estimating beam losses and background from neutron optics.

  10. Neutron lifetime measurement with pulsed beam at JPARC: Overview

    NASA Astrophysics Data System (ADS)

    Mishima, Kenji; Ino, Takashi; Taketani, Kaoru; Yamada, Takahito; Katayama, Ryo; Higashi, Nao; Yokoyama, Harumichi; Sumino, Hirochika; Yamashita, Satoru; Sakakibara, Risa; Sugino, Tomoaki; Kitaguchi, Masaaki; Hirota, Katsuya; Shimizu, Hirohiko M.; Tanaka, Genki; Sumi, Naoyuki; Otono, Hidetoshi; Yoshioka, Tamaki; Kitahara, Ryunosuke; Iwashita, Yoshihisa; Oide, Hideyuki; Shima, Tatsushi; Seki, Yoshichika; NOP Collaboration

    2014-09-01

    The neutron lifetime is an important parameter for a test of the Standard Model of elementary particles, as well for the production of light mass nuclei in big bang nucleosynthesis. There are two principally different approaches to measure the neutron lifetime: In-beam methods and storage of ultracold neutron. At present, there is a discrepancy of 8.4 sec (3.8 sigma) between the two methods. We are performing a new In-beam experiment with an intense pulsed neutron source at J-PARC, which has different systematic uncertainties from the previous experiments. We introduce the overview of the experiment and report present status.

  11. Angle dependence of response characteristics of neutron survey instruments.

    PubMed

    Roberts, N J; Bartlett, D T; Hager, L G; Jones, L N; Molinos, C; Tanner, R J; Taylor, G C; Thomas, D J

    2004-01-01

    Neutron area survey instruments are designed to have an approximately isotropic response. In practice, the response cannot be perfectly isotropic for instruments that do not have spherical symmetry, and for all instruments it is modified by the inclusion of batteries, electronics, handles, etc. This affects the ability of the survey instrument to measure accurately an isotropic dose equivalent quantity. Measurements of the angle dependence of response for four of the most commonly used designs of survey instrument (Harwell 0949, Mark 7 NRM, NM2 and Studsvik 2202D) have been performed in a low-scatter room using radionuclide and monoenergetic neutron sources. The Monte Carlo code MCNP has been used to model the responses and to investigate their sensitivity to the polyethylene density, counting gas pressure and other manufacturing tolerances. Preliminary modelling results are presented here.

  12. A multipurpose fast neutron beam capability at the MASURCA facility

    SciTech Connect

    Dioni, Luca; Stout, Brian

    2015-07-01

    In this paper we investigate the possible future use of the CEA Cadarache MASURCA experimental fast reactor to generate a fairly high-intensity continuous beam of fast neutrons, having energies distributed in the 1 KeV to 5 MeV range. Such an extracted beam of fast neutrons, tailorable in intensity, size and energy, would be rather unique; it would be of interest to neutron-based research and could open a range of new applications at MASURCA. We report the results of numerical simulations which have been performed to evaluate the feasibility of such a beam port and to characterize it spectrally. (authors)

  13. High intensity multi beam design of SANS instrument for Dhruva reactor

    NASA Astrophysics Data System (ADS)

    Abbas, Sohrab; Désert, S.; Aswal, V. K.

    2016-05-01

    A new and versatile design of Small Angle Neutron Scattering (SANS) instrument based on utilization of multi-beam is presented. The multi-pinholes and multi-slits as SANS collimator for medium flux Dhruva rearctor have been proposed and their designs have been validated using McStas simulations. Various instrument configurations to achieve different minimum wave vector transfers in scattering experiments are envisioned. These options enable smooth access to minimum wave vector transfers as low as ~ 6×10-4 Å-1 with a significant improvement in neutron intensity, allowing faster measurements. Such angularly well defined and intense neutron beam will allow faster SANS studies of agglomerates larger than few tens of nm.

  14. Enhancing Neutron Beam Production with a Convoluted Moderator

    SciTech Connect

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

    2014-10-01

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

  15. 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.

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

    PubMed

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

    2004-01-01

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

  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. Measuring the Density of Different Materials by Using the Collimated Fast Neutron Beam

    SciTech Connect

    Sudac, D.; Nad, K.; Orlic, Z.; Obhodas, J.; Valkovic, V.

    2015-07-01

    It was demonstrated in the previous work that various threat materials could be detected inside the sea going cargo container by measuring the three variables, carbon and oxygen concentration and density of investigated material. Density was determined by measuring transmitted neutrons, which is not always practical in terms of setting up the instrument geometry. In order to enable more geometry flexibility, we have investigated the possibility of using the scattered neutrons in cargo material identification. For that purpose, the densities of different materials were measured depending on the position of neutron detectors and neutron generator with respect to the target position. One neutron detector was put above the target, one behind and one in front of the target, above the neutron generator. It was shown that all three positions of neutron detectors can be successfully used to measure the target density, but only if the detected neutrons are successfully discriminated from the gamma rays. Although the associated alpha particle technique/associate particle imaging (API) was used to discriminate the neutrons from the gamma rays, it is believed that the same results would be obtained by using the pulse shape discrimination method. In that way API technique can be avoided and the neutron generator which produces much higher beam intensity than 10{sup 8} n/s can be used. (authors)

  19. Neutrons and music: Imaging investigation of ancient wind musical instruments

    NASA Astrophysics Data System (ADS)

    Festa, G.; Tardino, G.; Pontecorvo, L.; Mannes, D. C.; Senesi, R.; Gorini, G.; Andreani, C.

    2014-10-01

    A set of seven musical instruments and two instruments cares from the 'Fondo Antico della Biblioteca del Sacro Convento' in Assisi, Italy, were investigated through neutron and X-ray imaging techniques. Historical and scientific interests around ancient musical instruments motivate an intense research effort for their characterization using non-destructive and non-invasive techniques. X-ray and neutron tomography/radiography were applied to the study of composite material samples containing wood, hide and metals. The study was carried out at the NEUTRA beamline, PSI (Paul Scherrer Institute, Switzerland). Results of the measurements provided new information on the composite and multi-scale structure, such as: the internal structure of the samples, position of added materials like metals, wood fiber displays, deformations, presence of adhesives and their spatial distribution and novel insight about construction methods to guide the instruments' restoration process.

  20. Development of a polarized neutron beam line at Algerian research reactors using McStas software

    NASA Astrophysics Data System (ADS)

    Makhloufi, M.; Salah, H.

    2017-02-01

    Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway.

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

    PubMed

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

    2016-01-01

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

  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. Neutron depth profiling of elemental concentration using a focused beam

    NASA Astrophysics Data System (ADS)

    Chen-Mayer, Huaiyu H.; Lamaze, G. P.; Mildner, David F. R.; Downing, Robert G.

    1997-02-01

    Neutron Depth Profiling (NDP) is a nondestructive analytical technique for measuring the concentration of certain light elements as a function of depth near the surface of a solid matrix. The concentration profile is determined by analyzing the energy spectrum of the charged particles emitted as a result of neutron capture by the elements. The measurement sensitivity is directly proportional to the neutron beam current density. A more intense neutron beam achieved by focusing improves sensitivity for specimens of small area. In addition, a narrowly focused beam adds lateral spatial resolution to the technique, which is advantageous compared with that obtained by collimating the beam size using apertures. Capillary neutron lenses have been shown to focus a neutron beam to sub-millimeter spot size. Preliminary tests have been performed in the NDP geometry using such a focusing device. A lateral resolution in the sub-millimeter range is demonstrated by a specimen of non-uniform lateral distribution composed of a row of borosilicate glass fibers.

  4. 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.

  5. 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.

  6. 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.

  7. Neutron cross section standards and instrumentation. Annual report

    SciTech Connect

    Wasson, O.A.

    1993-07-01

    The objective of this interagency program is to provide accurate neutron interaction measurements for the US Department of Energy nuclear programs which include waste disposal, fusion, safeguards, defense, fission, and personnel protection. These measurements are also useful to other energy programs which indirectly use the unique properties of the neutron for diagnostic and analytical purposes. The work includes the measurement of reference cross sections and related neutron data employing unique facilities and capabilities at NIST and other laboratories as required; leadership and participation in international intercomparisons and collaborations; the preservation of standard reference deposits and the development of improved neutron detectors and measurement methods. A related and essential element of the program is critical evaluation of neutron interaction data including international coordinations. Data testing of critical data for important applications is included. The program is jointly supported by the Department of Energy and the National Institute of Standards and Technology. This report from the National Institute of Standards and Technology contains a summary of the accomplishments of the Neutron Cross Section Standards and Instrumentation Project during the third year of this three-year interagency agreement. The proposed program and required budget for the following three years are also presented. The program continues the shifts in priority instituted in order to broaden the program base.

  8. 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.

  9. 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.

  10. Operational Performance of LCLS Beam Instrumentation

    SciTech Connect

    Loos, Henrik; Akre, R.; Brachmann, A.; Coffee, R.; Decker, F.-J.; Ding, Y.; Dowell, D.; Edstrom, S.; Emma, P.; Fisher, A.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Huang, Z.; Iverson, R.; Messerschmidt, M.; Miahnahri, A.; Moeller, S.; Nuhn, H.-D.; Ratner, D.; /SLAC /LLNL, Livermore

    2010-06-15

    The Linac Coherent Light Source (LCLS) X-ray FEL utilizing the last km of the SLAC linac has been operational since April 2009 and finished its first successful user run last December. The various diagnostics for electron beam properties including beam position monitors, wire scanners, beam profile monitors, and bunch length diagnostics are presented as well as diagnostics for the X-ray beam. The low emittance and ultra-short electron beam required for X-ray FEL operation has implications on the transverse and longitudinal diagnostics. The coherence effects of the beam profile monitors and the challenges of measuring fs long bunches are discussed.

  11. Study of the neutron beam line shield design for JSNS.

    PubMed

    Kawai, M; Saito, K; Sanami, T; Nakao, N; Maekawa, F

    2005-01-01

    The JSNS, a spallation neutron source of J-PARC (JAERI-KEK Joint Project of the High Intensity Proton Accelerator) has 23 neutron beam lines. In the present study, a database was formulated for an optimum shielding design using the MCNP-X code. The calculations involved two steps. In the first step, the neutron distributions were created in the typical neutron beam line with a model that included the spallation neutron source target. The neutron currents evaluated flowed from the duct into the duct wall which was the boundary source for the bulk shield surrounding the beam line. In the second step, bulk-shield calculations were performed for the various shielding materials (iron, concrete, heavy concrete and so on) used and their composites up to thicknesses of 3 m. The results were compared with each other. Composite material shields of iron and such hydrogeneous materials as polyethylene or concrete were more effective. A typical design was prepared for a beam line within 25 m distance from a moderator, as a sample.

  12. 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.

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

    PubMed

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

    1991-01-01

    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 greater than 200 g/cm2 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.

  14. Delayed neutron detection with an integrated differential die-away and delayed neutron instrument

    SciTech Connect

    Blanc, Pauline; Tobin, Stephen J; Lee, Taehoon; Hu, Jianwei S; Hendricks, John; Croft, Stephen

    2010-01-01

    The Next Generation Safeguards Initiative (NGSI) of the U.S. Department of Energy (DOE) has funded a multilab/university collaboration to quantify the plutonium (Pu) mass and detect the diversion of pins from spent nuclear fuel. The first two years of this NGSI effort was focused on quantifying the capability of a range of nondestructive assay (NDA) techniques with Monte Carlo (MCNPX) modeling and the second current phase involves measuring Spent Fuel. One of the techniques of interest in this paper involves measuring delayed neutrons. A delayed neutron instrument using 36 fission chambers and a 14 MeV neutron generator so called DT generator (Deuterium + Tritium) surrounding the fuel was previously studied as part of the NGSI effort. This paper will quantify the capability of a standalone delayed neutron instrument using 4 {sup 3}He gas filled tubes and a DT generator with significant spectrum tailoring, located far from the fuel. So that future research can assess how well a delayed neutron instrument will function as part of an integrated NDA system. A new design is going to be used to respond to the need of the techniques. This design has been modeled for a water media and is currently being optimized for borated water and air media as part of ongoing research. This new design was selected in order to minimize the fission of {sup 238}U, to use a more realistic neutron generator design in the model, to reduce cost and facilitate the integration of a delayed neutron (DN) with a differential die-away (DDA) instrument. Since this paper will focus on delayed neutron detection, the goal is to quantify the signal from {sup 235}U, {sup 239}Pu and {sup 241}Pu, which are the isotopes present in Spent Fuel that respond significantly to a neutron interrogation. This report will quantify the capability of this new delayed neutron design to measure the combined mass of {sup 235}U, {sup 239}Pu and {sup 241}Pu for 16 of the 64 assemblies of the NGSI Spent Fuel library in one

  15. Secondary Neutron Doses for Several Beam Configurations for Proton Therapy

    SciTech Connect

    Shin, Dongho; Yoon, Myonggeun; Kwak, Jungwon; Shin, Jungwook; Lee, Se Byeong Park, Sung Yong; Park, Soah; Kim, Dae Yong; Cho, Kwan Ho

    2009-05-01

    Purpose: To compare possible neutron doses produced in scanning and scattering modes, with the latter assessed using a newly built passive-scattering proton beam line. Methods and Materials: A 40 x 30.5 x 30-cm water phantom was irradiated with 230-MeV proton beams using a gantry angle of 270{sup o}, a 10-cm-diameter snout, and a brass aperture with a diameter of 7 cm and a thickness of 6.5 cm. The secondary neutron doses during irradiation were measured at various points using CR-39 detectors, and these measurements were cross-checked using a neutron survey meter with a 22-cm range and a 5-cm spread-out Bragg peak. Results: The maximum doses due to secondary neutrons produced by a scattering beam-delivery system were on the order of 0.152 mSv/Gy and 1.17 mSv/Gy at 50 cm from the beam isocenter in the longitudinal (0{sup o}) and perpendicular (90{sup o}) directions, respectively. The neutron dose equivalent to the proton absorbed dose, measured from 10 cm to 100 cm from the isocenter, ranged from 0.071 mSv/Gy to 1.96 mSv/Gy in the direction of the beam line (i.e., {phi} = 0 deg.). The largest neutron dose, of 3.88 mSv/Gy, was observed at 135{sup o} and 25 cm from the isocenter. Conclusions: Although the secondary neutron doses in proton therapy were higher when a scattering mode rather than a scanning mode was used, they did not exceed the scattered photon dose in typical photon treatments.

  16. Fluence and dose measurements for an accelerator neutron beam

    NASA Astrophysics Data System (ADS)

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

    2007-10-01

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

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

    PubMed

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

    1999-07-01

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

  18. 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}.

  19. Instrument and method for focusing x rays, gamma rays, and neutrons

    DOEpatents

    Smither, R.K.

    1981-04-20

    A crystal diffraction instrument is described which has an improved crystalline structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg angle and thereby increasing the usable area and acceptance angle. The increased planar spacing is provided by the use of a temperature differential across the crystalline structure, by assembling a plurality of crystalline structure with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques.

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

    SciTech Connect

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

    2007-07-31

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

  1. Tuning the beam: a physics perspective on beam diagnostic instrumentation

    SciTech Connect

    Gulley, Mark S

    2010-01-01

    In a nutshell, the role of a beam diagnostic measurement is to provide information needed to get a particle beam from Point A (injection point) to Point B (a target) in a useable condition, with 'useable' meaning the right energy and size and with acceptable losses. Specifications and performance requirements of diagnostics are based on the physics of the particle beam to be measured, with typical customers of beam parameter measurements being the accelerator operators and accelerator physicists. This tutorial will be a physics-oriented discussion of the interplay between tuning evolutions and the beam diagnostics systems that support the machine tune. This will include the differences between developing a tune and maintaining a tune, among other things. Practical longitudinal and transverse tuning issues and techniques from a variety of proton and electron machines will also be discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  3. 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.

  4. Beam Instrumentation of the PXIE LEBT Beamline

    SciTech Connect

    D'Arcy, R.; Hanna, B.; Prost, L.; Scarpine, v.; Shemyakin, A.

    2015-06-01

    The PXIE accelerator [1] is the front-end test stand of the proposed Proton Improvement Plan (PIP-II) [2] initiative: a CW-compatible pulsed H- superconducting RF linac upgrade to Fermilab’s injection system. The PXIE Ion Source and Low-Energy Beam Transport (LEBT) section are designed to create and transfer a 1-10 mA $H^{-}$ beam, in either pulsed (0.001–16 ms) or DC mode, from the ion source through to the injection point of the RFQ. This paper discusses the range of diagnostic tools – Allison-type Emittance Scanner, Faraday Cup, Toroid, DCCT, electrically isolated diaphragms – involved in the commissioning of the beam line and preparation of the beam for injection into the RFQ.

  5. Compact Instrument for Measuring Profile of a Light Beam

    NASA Technical Reports Server (NTRS)

    Papanyan, Valeri

    2004-01-01

    The beamviewer is an optical device designed to be attached to a charge-coupled-device (CCD) image detector for measuring the spatial distribution of intensity of a beam of light (the beam profile ) at a designated plane intersecting the beam. The beamviewer-and-CCD combination is particularly well suited for measuring the radiant- power profile (for a steady beam) or the radiant-energy profile (for a pulsed beam) impinging on the input face or emerging from the output face of a bundle of optical fibers. The beamviewer and-CCD combination could also be used as a general laboratory instrument for profiling light beams, including beams emerging through small holes and laser beams in free space.

  6. 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

  7. 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.

  8. Development of time projection chamber for precise neutron lifetime measurement using pulsed cold neutron beams

    NASA Astrophysics Data System (ADS)

    Arimoto, Y.; Higashi, N.; Igarashi, Y.; Iwashita, Y.; Ino, T.; Katayama, R.; Kitaguchi, M.; Kitahara, R.; Matsumura, H.; Mishima, K.; Nagakura, N.; Oide, H.; Otono, H.; Sakakibara, R.; Shima, T.; Shimizu, H. M.; Sugino, T.; Sumi, N.; Sumino, H.; Taketani, K.; Tanaka, G.; Tanaka, M.; Tauchi, K.; Toyoda, A.; Tomita, T.; Yamada, T.; Yamashita, S.; Yokoyama, H.; Yoshioka, T.

    2015-11-01

    A new time projection chamber (TPC) was developed for neutron lifetime measurement using a pulsed cold neutron spallation source at the Japan Proton Accelerator Research Complex (J-PARC). Managing considerable background events from natural sources and the beam radioactivity is a challenging aspect of this measurement. To overcome this problem, the developed TPC has unprecedented features such as the use of polyether-ether-ketone plates in the support structure and internal surfaces covered with 6Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

  9. Upgrade of detectors of neutron instruments at Neutron Physics Laboratory in Řež

    NASA Astrophysics Data System (ADS)

    Litvinenko, E. I.; Ryukhtin, V.; Bogdzel, A. A.; Churakov, A. V.; Farkas, G.; Hervoches, Ch.; Lukas, P.; Pilch, J.; Saroun, J.; Strunz, P.; Zhuravlev, V. V.

    2017-01-01

    Three neutron instruments at the Neutron Physics Laboratory (NPL) in Řež near Prague - small-angle scattering (SANS) MAUD, strain scanner SPN-100 and strain diffractometer TKSN-400 - have been modernized recently with new 2D position-sensitive detectors (PSDs) from JINR, Dubna. Here we report on the progress made in relation to the possibilities of the diffractometers due to the improved performance of the detectors. The first part of the paper is dedicated to a detailed description of the hardware and software of the PSDs, as well as its integration with the in-house experimental control software. Then practical examples of neutron scattering experiments for each of the upgraded facilities are presented.

  10. Calibration of the GNU and HSREM neutron survey instruments

    NASA Astrophysics Data System (ADS)

    Eakins, J. S.; Hager, L. G.; Leake, J. W.; Mason, R. S.; Tanner, R. J.

    2017-04-01

    Two innovative designs of neutron survey instrument have recently been developed to estimate ambient dose equivalent in the workplace: the GNU has an improved energy-independence of response in the meV to TeV range; the HSREM is a comparatively lightweight device covering the meV to 10 MeV range. Both designs offer good detection sensitivity, allowing measurements to be made efficiently and thereby minimizing the exposure to their users. Prototypes of both devices have been constructed and exposed to sets of well-characterized reference fields: the resulting measured responses are presented and discussed here, compared against comprehensive Monte Carlo data.

  11. Virtual experiments: Combining realistic neutron scattering instrument and sample simulations

    NASA Astrophysics Data System (ADS)

    Farhi, E.; Hugouvieux, V.; Johnson, M. R.; Kob, W.

    2009-08-01

    A new sample component is presented for the Monte Carlo, ray-tracing program, McStas, which is widely used to simulate neutron scattering instruments. The new component allows the sample to be described by its material dynamic structure factor, which is separated into coherent and incoherent contributions. The effects of absorption and multiple scattering are treated and results from simulations and previous experiments are compared. The sample component can also be used to treat any scattering material which may be close to the sample and therefore contaminates the total, measured signal.

  12. Instrumental neutron activation analysis of archaeological ceramics: scale and interpretation.

    PubMed

    Bishop, Ronald L; Blackman, M James

    2002-08-01

    Instrumental neutron activation analysis has become a standard technique for the study of the production and distributional patterns of archaeological pottery. Questions once framed within the context of long distance exchange are now focused on issues of subregional and even intrasite levels. The increasing specificity at which these questions are poised requires a high level of analytical precision as we seek to observe statistically and archaeologically significant differences among groups of pottery produced from geographically closely spaced resources or the compositional differences that arise from production behaviors of the producers of the pottery.

  13. Dual cathode system for electron beam instruments

    NASA Technical Reports Server (NTRS)

    Bradley, James G. (Inventor); Conley, Joseph M. (Inventor); Wittry, David B. (Inventor)

    1989-01-01

    An electron beam source having a single electron optical axis is provided with two coplanar cathodes equally spaced on opposite sides from the electron optical axis. A switch permits selecting either cathode, and a deflection system comprised of electromagnets, each with separate pole pieces equally spaced from the plane of the cathodes and electron optical axis, first deflects the electron beam from a selected cathode toward the electron optical axis, and then in an opposite direction into convergence with the electron optical axis. The result is that the electron beam from one selected cathode undergoes a sigmoid deflection in two opposite directions, like the letter S, with the sigmoid deflection of each being a mirror image of the other.

  14. Beam instrumentation for an ISOL test stand

    SciTech Connect

    Mackenzie, G.H.; Dombsky, M.; Rawnsley, W.; Stanford, G.; Yin, Y.; Novikov, A.

    1995-09-01

    TRIUMF is constructing a test bed for the first stages of the proposed TISAC accelerated radioactive beam facility. The authors will present the requirements for the diagnostic system for this test stand and describe the design and development work underway. Scintillators, beamstops and a Faraday Cup have been tested using stable, mass analyzed, 12 keV beams of ions from mass 14 to 132. The design of a linear drive, with 10 {micro}m resolution, for scanning wires and slits has begun.

  15. Beam Instrumentation Challenges at the International Linear Collider

    SciTech Connect

    Tenenbaum, Peter; /SLAC

    2006-05-16

    The International Linear Collider (ILC) is a proposed facility for the study of high energy physics through electron-positron collisions at center-of-mass energies up to 500 GeV and luminosities up to 2 x 10{sup 34} cm{sup -2} sec{sup -1}. Meeting the ILC's goals will require an extremely sophisticated suite of beam instruments for the preservation of beam emittance, the diagnosis of optical errors and mismatches, the determination of beam properties required for particle physics purposes, and machine protection. The instrumentation foreseen for the ILC is qualitatively similar to equipment in use at other accelerator facilities in the world, but in many cases the precision, accuracy, stability, or dynamic range required by the ILC exceed what is typically available in today's accelerators. In this paper we survey the beam instrumentation requirements of the ILC and describe the system components which are expected to meet those requirements.

  16. Computer dosimetry for flattened and wedged fast-neutron beams.

    PubMed

    Hogstrom, K R; Smith, A R; Almond, P R; Otte, V A; Smathers, J B

    1976-01-01

    Beam flattening by the use of polyethylene filters has been developed for the 50-MeV d in equilibrium Be fast-neutron therapy beam at the Texas A&M Variable-Energy Cyclotron (TAMVEC) as a result of the need for a more uniform dose distribution at depth within the patient. A computer algorithm has been developed that allows the use of a modified decrement line method to calculate dose distributions; standards decrement line methods do not apply because of off-axis peaking. The dose distributions for measured flattened beams are transformed into distributions that are physically equivalent to an unflattened distribution. In the transformed space, standard decrement line theory yields a distribution for any field size which, by applying the inverse transformation, generates the flattened dose distribution, including the off-axis peaking. A semiempirical model has been constructed that allows the calculation of dose distributions for wedged beams from open-beam data.

  17. Instrument and method for focusing x rays, gamma rays, and neutrons

    DOEpatents

    Smither, R.K.

    1982-03-25

    A crystal-diffraction instrument or diffraction-grating instrument is described with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the line structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam, or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal-diffraction case.

  18. Instrument and method for focusing X-rays, gamma rays and neutrons

    DOEpatents

    Smither, Robert K.

    1984-01-01

    A crystal diffraction instrument or diffraction grating instrument with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the crystalline structure, by assembling a plurality of crystalline structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal diffraction case.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  1. 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.

  2. 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.

  3. Elastic Scattering Spectroscopy (ESS): an Instrument-Concept for Dynamics of Complex (Bio-) Systems From Elastic Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Benedetto, Antonio; Kearley, Gordon J.

    2016-10-01

    A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics.

  4. Elastic Scattering Spectroscopy (ESS): an Instrument-Concept for Dynamics of Complex (Bio-) Systems From Elastic Neutron Scattering.

    PubMed

    Benedetto, Antonio; Kearley, Gordon J

    2016-10-05

    A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics.

  5. Elastic Scattering Spectroscopy (ESS): an Instrument-Concept for Dynamics of Complex (Bio-) Systems From Elastic Neutron Scattering

    PubMed Central

    Benedetto, Antonio; Kearley, Gordon J.

    2016-01-01

    A new type of neutron-scattering spectroscopy is presented that is designed specifically to measure dynamics in bio-systems that are difficult to obtain in any other way. The temporal information is largely model-free and is analogous to relaxation processes measured with dielectric spectroscopy, but provides additional spacial and geometric aspects of the underlying dynamics. Numerical simulations of the basic instrument design show the neutron beam can be highly focussed, giving efficiency gains that enable the use of small samples. Although we concentrate on continuous neutron sources, the extension to pulsed neutron sources is proposed, both requiring minimal data-treatment and being broadly analogous with dielectric spectroscopy, they will open the study of dynamics to new areas of biophysics. PMID:27703184

  6. Optimizations in angular dispersive neutron powder diffraction using divergent beam geometries

    NASA Astrophysics Data System (ADS)

    Buchsteiner, Alexandra; Stüßer, Norbert

    2009-01-01

    Angular dispersive neutron powder diffractometers are usually built using beam divergencies defined by Soller type collimators. To account for the needs of resolution for crystal structure refinement a good in-pile collimation α1, a high take-off angle above 90∘ at the monochromator and a good collimation α3 in front of the detector bank are chosen whereas the value of α2 for the collimation between monochromator and sample is less crucial. During the last years new strategies were developed at our institute using wide divergent beam geometries defined by fan collimators or slit-type diaphragms which correlate ray direction and wavelength within the beam. Here we present the performance of a newly developed fan collimator, which enables one to adjust the opening of the collimator channels on both sides independently. This fan collimator is positioned in front of the monochromator at the instrument E6 at the Helmholtz Centre Berlin (formerly Hahn-Meitner-Institut Berlin). It will be shown that control of the beam divergency allows optimization of the resolution in a large angular diffraction range. Hence the resolution and intensity can be adapted to the needs of powder diffraction. Monte Carlo simulations using McStas are used to check and prove the optimal setting of the instrument. We obtain a very good agreement between experimental and simulated data and demonstrate the superior outcome of the new instrument configuration with respect to Soller type instruments.

  7. From x-ray telescopes to neutron scattering: Using axisymmetric mirrors to focus a neutron beam

    NASA Astrophysics Data System (ADS)

    Khaykovich, B.; Gubarev, M. V.; Bagdasarova, Y.; Ramsey, B. D.; Moncton, D. E.

    2011-03-01

    We demonstrate neutron beam focusing by axisymmetric mirror systems based on a pair of mirrors consisting of a confocal ellipsoid and hyperboloid. Such a system, known as a Wolter mirror configuration, is commonly used in X-ray telescopes. The axisymmetric Wolter geometry allows nesting of several mirror pairs to increase collection efficiency. We implemented a system containing four nested Ni mirror pairs, which was tested by the focusing of a polychromatic neutron beam at the MIT Reactor. In addition, we have carried out extensive ray-tracing simulations of the mirrors and their performance in different situations. The major advantages of the Wolter mirrors are nesting for large angular collection and aberration-free performance. We discuss how these advantages can be utilized to benefit various neutron scattering methods, such as imaging, SANS, and time-of-flight spectroscopy.

  8. 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

  9. Beam instrumentation for the BNL Heavy Ion Transfer Line

    SciTech Connect

    Witkover, R.L.; Buxton, W.; Castillo, V.; Feigenbaum, I.; Lazos, A.; Li, Z.G.; Smith, G.; Stoehr, R.

    1987-01-01

    The Heavy Ion Transfer Line (HITL) was constructed to transport beams from the BNL Tandem Van de Graaff (TVDG) to be injected into the AGS. Because the beam line is approximately 2000 feet long and the particle rigidity is so low, 20 beam monitor boxes were placed along the line. The intensity ranges from 1 to 100 nanoAmps for the dc trace beam used for line set-up, to over 100 ..mu..A for the pulsed beam to be injected into the AGS. Profiles are measured using multiwire arrays (HARPS) while Faraday cups and beam transformers monitor the intensity. The electronics stations are operated through 3 Instrumentation Controllers networked to Apollo workstations in the TVDG and AGS control rooms. Details of the detectors and electronics designs and performance will be given.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  11. 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.

  12. Determination of the thermal neutron flux in a fast neutron beam by use of a boron-coated ionization chamber.

    PubMed

    Lüdemann, L; Matzen, T; Matzke, M; Schmidt, R; Scobel, W

    1995-11-01

    The thermal neutron distribution in slow and fast neutron beams is usually determined using the foil activation method. In this work a small magnesium walled ionization chamber, in which the inner surface of the wall has been coated with 10B to increase the sensitivity for thermal neutrons, is used to estimate the thermal neutron component of the beam. After calibration and determination of the directional response in a thermal neutron beam a comparison with foil activation at different depths in water was performed to investigate the reliability of the ionization measurements. The chamber was used in a computer controlled water phantom to measure the depth and lateral distribution of the thermal neutron dose. With this arrangement two-dimensional scans of the thermal neutrons could be performed quickly and with high accuracy.

  13. Recent accomplishments in neutron beam projects at the University of Texas Research Reactor

    SciTech Connect

    Uenlue, K.; Wehring, B.W.

    1994-12-31

    The design of a cold neutron source facility at the University of Texas TRIGA research reactor is described. The UT-TRIGA has 5 neutron beam ports. Because of the different characteristics of the ports, various research projects are being pursued. Among these projects, The Texas cold neutron source and neutron depth profiling are operational; neutron focusing, prompt gamma activation analysis, and neutron capture therapy research are progressing.

  14. Skin-sparing effects of neutron beam filtering materials.

    PubMed

    Otte, V A; Almond, P R; Smathers, J B; Attix, F H

    1987-01-01

    The skin-sparing effects of several filtering materials for fast neutron beams were studied under various conditions. A parallel-plate ionization chamber was used for the measurements. The parameters which were studied included field size, distance from filter to ion chamber, filter material, and filter thickness. On the basis of this work, Teflon (polytetrafluoroethylene) was chosen for fabrication of flattening filters and wedges.

  15. Neutron scattering and diffraction instrument for structural study on biology in Japan

    SciTech Connect

    Niimura, Nobuo

    1994-12-31

    Neutron scattering and diffraction instruments in Japan which can be used for structural studies in biology are briefly introduced. Main specifications and general layouts of the instruments are shown.

  16. 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.

  17. The new small-angle neutron scattering instrument SANS-1 at MLZ-characterization and first results

    NASA Astrophysics Data System (ADS)

    Mühlbauer, S.; Heinemann, A.; Wilhelm, A.; Karge, L.; Ostermann, A.; Defendi, I.; Schreyer, A.; Petry, W.; Gilles, R.

    2016-10-01

    A thorough characterization of the key features of the new small-angle neutron scattering instrument SANS-1 at MLZ, a joint project of Technische Universität München and Helmholtz Zentrum Geesthacht, is presented. Measurements of the neutron beam profile, divergency and flux are given for various positions along the instrument including the sample position, and agree well with Monte Carlo simulations of SANS-1 using the program McStas. Secondly, the polarization option of SANS-1 is characterized for a broad wavelength band. A key feature of SANS-1 is the large accessible Q-range facilitated by the sideways movement of the detector. Particular attention is hence paid to the effects that arise due to large scattering angles on the detector where a standard cos3 solid angle correction is no longer applicable. Finally the performance of the instrument is characterized by a set of standard samples.

  18. Neutron Zeeman beam-splitting for the investigation of magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Kozhevnikov, S. V.; Ott, F.; Semenova, E.

    2017-03-01

    Zeeman spatial splitting of a neutron beam takes place during a neutron spin-flip in magnetically non-collinear systems at grazing incidence geometry. We apply the neutron beam-splitting method for the investigation of magnetically non-collinear clusters of submicron size in a thin film. The experimental results are compared with ones obtained by other methods.

  19. 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.

  20. Proceedings of a workshop on methods for neutron scattering instrumentation design

    SciTech Connect

    Hjelm, R.P.

    1997-09-01

    The future of neutron and x-ray scattering instrument development and international cooperation was the focus of the workshop. The international gathering of about 50 participants representing 15 national facilities, universities and corporations featured oral presentations, posters, discussions and demonstrations. Participants looked at a number of issues concerning neutron scattering instruments and the tools used in instrument design. Objectives included: (1) determining the needs of the neutron scattering community in instrument design computer code and information sharing to aid future instrument development, (2) providing for a means of training scientists in neutron scattering and neutron instrument techniques, and (3) facilitating the involvement of other scientists in determining the characteristics of new instruments that meet future scientific objectives, and (4) fostering international cooperation in meeting these needs. The scope of the meeting included: (1) a review of x-ray scattering instrument design tools, (2) a look at the present status of neutron scattering instrument design tools and models of neutron optical elements, and (3) discussions of the present and future needs of the neutron scattering community. Selected papers were abstracted separately for inclusion to the Energy Science and Technology Database.

  1. 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.

  2. 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.

  3. Instrumental neutron activation analysis of sectioned hair strands for arsenic

    SciTech Connect

    Guinn, V.P.

    1996-12-31

    Instrumental neutron activation analysis (INAA) is a valuable and proven method for the quantitative analysis of sectioned human head hair specimens for arsenic - and, if arsenic is found to be present at high concentrations, the approximate times when it was ingested. Reactor-flux thermal-neutron activation of the hair samples produces 26.3-h {sup 76}As, which is then detected by germanium gamma-ray spectrometry, measuring the 559.1-keV gamma-ray peak of {sup 76}As. Even normal levels of arsenic in hair, in the range of <1 ppm up to a few parts per million of arsenic can be measured - and the far higher levels associated with large internal doses of arsenic, levels approaching or exceeding 100 ppm arsenic, are readily and accurately measurable. However, all phases of forensic investigations of possible chronic (or in some cases, acute) arsenic poisoning are important, i.e., not just the analysis phase. All of these phases are discussed in this paper, based on the author`s experience and the experience of others, in criminal cases. Cases of chronic arsenic poisoning often reveal a series of two to four doses, perhaps a few months apart, with increasing doses.

  4. A Technique For Determining Neutron Beam Fluence to 0.01% Uncertainty

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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 monitor that detected the charged particle products from neutron absorption in a thin layer of 6Li or 10B. 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 material, 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 knowledge 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. We 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%.

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

    SciTech Connect

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

    2014-01-01

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

  6. Multimode laser beam analyzer instrument using electrically programmable optics.

    PubMed

    Marraccini, Philip J; Riza, Nabeel A

    2011-12-01

    Presented is a novel design of a multimode laser beam analyzer using a digital micromirror device (DMD) and an electronically controlled variable focus lens (ECVFL) that serve as the digital and analog agile optics, respectively. The proposed analyzer is a broadband laser characterization instrument that uses the agile optics to smartly direct light to the required point photodetectors to enable beam measurements of minimum beam waist size, minimum waist location, divergence, and the beam propagation parameter M(2). Experimental results successfully demonstrate these measurements for a 500 mW multimode test laser beam with a wavelength of 532 nm. The minimum beam waist, divergence, and M(2) experimental results for the test laser are found to be 257.61 μm, 2.103 mrad, 1.600 and 326.67 μm, 2.682 mrad, 2.587 for the vertical and horizontal directions, respectively. These measurements are compared to a traditional scan method and the results of the beam waist are found to be within error tolerance of the demonstrated instrument.

  7. An Electron Beam Profile Instrument Based on FBGs

    PubMed Central

    Sporea, Dan; Stăncălie, Andrei; Becherescu, Nicu; Becker, Martin; Rothhardt, Manfred

    2014-01-01

    Along with the dose rate and the total irradiation dose measurements, the knowledge of the beam localization and the beam profile/energy distribution in the beam are parameters of interest for charged particle accelerator installations when they are used in scientific investigations, industrial applications or medical treatments. The transverse profile of the beam, its position, its centroid location, and its focus or flatness depend on the instrument operating conditions or on the beam exit setup. Proof-of-concept of a new type of charged particle beam diagnostics based on fiber Bragg gratings (FBGs) was demonstrated. Its operating principle relies on the measurement of the peak wavelength changes for an array of FBG sensors as function of the temperature following the exposure to an electron beam. Periodically, the sensor irradiation is stopped and the FBG are force cooled to a reference temperature with which the temperature influencing each sensor during beam exposure is compared. Commercially available FBGs, and FBGs written in radiation resistant optical fibers, were tested under electron beam irradiation in order to study their possible use in this application. PMID:25157554

  8. A Workshop on Methods for Neutron Scattering Instrument Design. Introduction and Summary

    SciTech Connect

    Hjelm, Rex P.

    1996-12-31

    The future of neutron and x-ray scattering instrument development and international cooperation was the focus of the workshop on ``Methods for Neutron Scattering Instrument Design`` September 23-25 at the E.O. Lawrence Berkeley National Laboratory. These proceedings are a collection of a portion of the invited and contributed presentations.

  9. 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.

  10. Determining the wavelength spectrum of neutrons on the NG6 beam line at NCNR

    NASA Astrophysics Data System (ADS)

    Ivanov, Juliet

    2016-09-01

    Historically, in-beam experiments and bottle experiments have been performed to determine the lifetime of a free neutron. However, these two different experimental techniques have provided conflicting results. It is crucial to precisely and accurately elucidate the neutron lifetime for Big Bang Nucleosynthesis calculations and to investigate physics beyond the Standard Model. Therefore, we aimed to understand and minimize systematic errors present in the neutron beam experiment at the NIST Center for Neutron Research (NCNR). In order to reduce the uncertainty related to wavelength dependent corrections present in previous beam experiments, the wavelength spectrum of the NCNR reactor cold neutron beam must be known. We utilized a beam chopper and lithium detector to characterize the wavelength spectrum on the NG6 beam line at the NCNR. The experimental design and techniques employed will be discussed, and our results will be presented. Future plans to utilize our findings to improve the neutron lifetime measurement at NCNR will also be described.

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

    PubMed

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

    2000-01-01

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

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

    PubMed

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

    1993-08-01

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

  13. 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.

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

    SciTech Connect

    Burns, Jr., Thomas Dean

    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 x 108 n/cm2 • s. The fast neutron and gamma radiation KERMA factors are 10 x 10-11cGy•cm2/nepi and 20 x 10-11 cGy•cm2/nepi , 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.

  15. First platinum moderated positron beam based on neutron capture

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, C.; Kögel, G.; Repper, R.; Schreckenbach, K.; Sperr, P.; Triftshäuser, W.

    2002-12-01

    A positron beam based on absorption of high energy prompt γ-rays from thermal neutron capture in 113Cd was installed at a neutron guide of the high flux reactor at the ILL in Grenoble. Measurements were performed for various source geometries, dependent on converter mass, moderator surface and extraction voltages. The results lead to an optimised design of the in-pile positron source which will be implemented at the Munich research reactor FRM-II. The positron source consists of platinum foils acting as γ-e +e --converter and positron moderator. Due to the negative positron work function moderation in heated platinum leads to emission of monoenergetic positrons. The positron work function of polycrystalline platinum was determined to 1.95(5) eV. After acceleration to several keV by four electrical lenses the beam was magnetically guided in a solenoid field of 7.5 mT leading to a NaI-detector in order to detect the 511 keV γ-radiation of the annihilating positrons. The positron beam with a diameter of less than 20 mm yielded an intensity of 3.1×10 4 moderated positrons per second. The total moderation efficiency of the positron source was about ɛ=1.06(16)×10 -4. Within the first 20 h of operation a degradation of the moderation efficiency of 30% was observed. An annealing procedure at 873 K in air recovers the platinum moderator.

  16. 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.

  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.

  18. Scattering-related contrast signals in neutron computerized tomography and the new V12 instrument at HMI Berlin

    NASA Astrophysics Data System (ADS)

    Strobl, Markus; Treimer, Wolfgang; Hilger, André

    2006-11-01

    Double-crystal diffractometers (DCD) are widely used for structural investigations at the limit between macroscopic and microscopic inner structures of sample materials. Operating in an ultra-small-angle scattering q-range between 10 -4 and 10 -1 nm -1 structures between 50 nm and nearly 100 μm can be resolved. Hence the DCD connects the resolvable ranges of small-angle neutron scattering (SANS) instruments and neutron tomography facilities. However, the DCD does not only link the resolvable size ranges but can also be operated to yield both, q-space information on microscopic structures combined with real space information in the range of macroscopic inner structures. This method was developed in recent years at the V12 DCD at HMI by introducing refraction and ultra-small-angle neutron scattering (USANS) contrast for tomography. The new V12 DCD set-up has now been optimized to exploit all the opportunities of USANS, refraction and USANS contrast tomography and conventional attenuation contrast tomography with an intense monochromatic neutron beam. The new contrast methods will be introduced as well as the final set-up of the V12 instrument. Additionally, several examples and results achieved by the new techniques and instrument will be given.

  19. 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.

  20. Scattering from condensates in turbulent jets. [for crossed beam instruments

    NASA Technical Reports Server (NTRS)

    Wilson, L. N.; Dennen, R. S.

    1970-01-01

    An analysis is made of the scattering signal levels to be expected from condensed water vapor droplets for crossed-beam instruments operating in the wavelength region. 18 to 4.3 microns. The results show that scattering should not present a problem for the infrared system operating under conditions typical of the IITRI jet facility. Actual measurements made for comparison indicate that scattering levels are appreciable, and presumably result from oil mist added by the facility air compressors.

  1. Nanodosimetric measurements and calculations in a neutron therapy beam.

    PubMed

    Grindborg, J-E; Lillhök, J E; Lindborg, L; Gudowska, I; Söderberg, J; Carlsson, G Alm; Nikjoo, H

    2007-01-01

    A comparison of calculated and measured values of the dose mean lineal energy (y(D)) for the former neutron therapy beam at Louvain-la-Neuve is reported. The measurements were made with wall-less tissue-equivalent proportional counters using the variance-covariance method and simulating spheres with diameters between 10 nm and 15 microm. The calculated y(D)-values were obtained from simulated energy distributions of neutrons and charged particles inside an A-150 phantom and from published y(D)-values for mono-energetic ions. The energy distributions of charged particles up to oxygen were determined with the SHIELD-HIT code using an MCNPX simulated neutron spectrum as an input. The mono-energetic ion y(D)-values in the range 3-100 nm were taken from track-structure simulations in water vapour done with PITS/KURBUC. The large influence on the dose mean lineal energy from the light ion (A > 4) absorbed dose fraction, may explain an observed difference between experiment and calculation. The latter being larger than earlier reported result. Below 50 nm, the experimental values increase while the calculated decrease.

  2. p(42)Be neutron therapy beams: dose rate and penetration as a function of target thickness and beam filtration.

    PubMed

    Rosenberg, I; Awschalom, M; Kuo, T Y; Tom, J L

    1981-01-01

    It is shown that, in the production of p(42)Be neutron beams for clinical use, the use of semithick targets leads to more desirable beam characteristics when appropriate backstop materials are used. Furthermore, an algebraic representation of beam penetration and of dose per unit charge on target, including hardening by polyethylene filters, provides a method for target optimization.

  3. 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.

  4. Global Maps of Lunar Neutron Fluxes from the LEND Instrument

    NASA Technical Reports Server (NTRS)

    Litvak, M. L.; Mitrofanov, I. G.; Sanin, A.; Malakhov, A.; Boynton, W. V.; Chin, G.; Droege, G.; Evans, L. G.; Garvin, J.; Golovin, D. V.; Harshman, K.; McClanahan, T. P.; Mokrousov, M. I.; Mazarico, E.; Milikh, G.; Neumann, G.; Sagdeev, R.; Smith, D. E.; Starr, R.; Zuber, M. T.

    2012-01-01

    The latest neutron spectrometer measurements with the Lunar Exploration Neutron Detector (LEND) onboard the Lunar Reconnaissance Orbiter (LRO) are presented. It covers more than 1 year of mapping phase starting on 15 September 2009. In our analyses we have created global maps showing regional variations in the flux of thermal (energy range < 0.015 eV) and fast neutrons (>0.5 MeV), and compared these fluxes to variances in soil elemental composition, and with previous results obtained by the Lunar Prospector Neutron Spectrometer (LPNS). We also processed data from LEND collimated detectors and derived a value for the collimated signal of epithermal neutrons based on the comparative analysis with the LEND omnidirectional detectors. Finally, we have compared our final (after the data reduction) global epithermal neutron map with LPNS data.

  5. Focused neutron beam dose deposition profiles in tissue equivalent materials: a pilot study for BNCT

    NASA Astrophysics Data System (ADS)

    Mayer, Rulon R.; Welsh, James; Chen-Mayer, Huaiyu H.

    1997-02-01

    Boron Neutron Capture Therapy (BNCT) has been limited by the inability to direct neutrons toward the therapeutic target and away from sensitive normal tissues. The recently developed Kumakhov lens has focused a broad incident low energy neutron beam in air to a sub-mm spot. This study examines the radiation does distribution of a converging beam passing through tissue equivalent materials. A neutron beam exiting a focusing lens is directed toward a stack of thin radiochromic media sandwiched between plastic sheets. The depth dose and beam profile within the tissue equivalent materials are determined by optical scanning and image processing of the individual radiochromic media sheets, a polymer based dosimetry medium which darkens upon exposure to ionizing radiation. The alpha particle emission from boron is examined by substituting a plastic sheet with a 6Li enriched lithium carbonate sheet positioned at the focal plane. The information will help determine the feasibility of applying the focused neutron beam to BNCT for therapy.

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

    PubMed

    Konijnenberg, M W; Dewit, L G; Mijnheer, B J; Raaijmakers, C P; Watkins, P R

    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 10B, the brain 5 ppm 10B and the tumor 30 ppm 10B. It was found that with a single 15-cm-diameter circular beam a very inhomogenous 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. Dose-volume histograms were evaluated for the planning target volume as well as for the healthy brain to compare different irradiation techniques, yielding a graphical confirmation of the above conclusions. Therapy with BNCT on brain tumors must be performed either with an 8-cm four

  7. Gaussian beam measurement for HIFI instrument: Herschel Space Observatory

    NASA Astrophysics Data System (ADS)

    Pantaleev, Miroslav G.; Ermisch, Karsten; Fredrixon, Mathias; Svensson, Magnus; Belitsky, Victor

    2004-09-01

    The Heterodyne Instrument (HIFI) is part of the ESA Herschel Space Observatory Project. The instrument is intended for high-resolution spectroscopy and has a frequency coverage from 480 to 1250 GHz band in five receiver bands and 1410 to 1910 GHz in two additional bands. HIFI is built based on a modular principle: the mixers together with their respective optics are integrated into Mixer Sub-Assemblies (MSA). Each frequency band has two MSAs allocated for horizontal and vertical polarization. In this paper, we present the work done on the design and construction of a Gaussian beam measurement range. One of the unique features of the developed method is a possibility to measure the beam parameters of the MSAs in the absolute coordinate system referred to the device under test. This along with other methods should allow integration of the entire HIFI with the best possible coupling of the antenna beam to the receivers and achieving ultimate performance in such a complicated optical system. The range houses the measured MSA, which is at 4 K ambient temperature, and a continuous wave source placed on a precise scanner entirely under vacuum. Developed triangulation system provides mechanical reference data on the MSA, in-situ, after the entire system is evacuated and the cooling is finished. We adopted a scalar measurement approach where the test source scans the receiver input beam and the mixer IF power is measured. The data collected from 3-4 planar scans are used to calculate the orientation and position of the optical axis. We present results from the first beam measurements for MSA HIFI bands 1 and 2 (480 and 640 GHz), the measurement system performance and accuracy analysis.

  8. Neutron guide system for small-angle neutron scattering instruments of the Jülich Centre for Neutron Science at the FRM-II

    NASA Astrophysics Data System (ADS)

    Radulescu, A.; Ioffe, A.

    2008-02-01

    Following the shut-down of the FRJ-2 research reactor in Jülich a large part of the neutron scattering instrumentation operating there is currently being moved to the FRM-II research reactor in Garching-München. The installation of these instruments requires the design and set-up of new neutron guides with geometrical and optical features imposed by the positioning of the instruments in the neutron guide hall and by the foreseen significant improvement of the instrument performance. Particularly three SANS diffractometers require a special approach due to on one hand, their pre-determined size and on the other hand, the demanded neutron wavelength range. Expected characteristics of three neutron guides (currently under construction) optimized using VITESS and McStas simulation packages, namely the vertically "S-shaped" guides serving the KWS2 and KWS1 conventional SANS instruments and the horizontally "S-shaped" guide serving the focusing KWS3 instrument, will be reported on.

  9. Monte Carlo simulations of neutron-scattering instruments using McStas

    NASA Astrophysics Data System (ADS)

    Nielsen, K.; Lefmann, K.

    2000-06-01

    Monte Carlo simulations have become an essential tool for improving the performance of neutron-scattering instruments, since the level of sophistication in the design of instruments is defeating purely analytical methods. The program McStas, being developed at Risø National Laboratory, includes an extension language that makes it easy to adapt it to the particular requirements of individual instruments, and thus provides a powerful and flexible tool for constructing such simulations. McStas has been successfully applied in such areas as neutron guide design, flux optimization, non-Gaussian resolution functions of triple-axis spectrometers, and time-focusing in time-of-flight instruments.

  10. Boron neutron capture therapy for the treatment of cerebral gliomas. I. Theoretical evaluation of the efficacy of various neutron beams.

    PubMed

    Zamenhof, R G; Murray, B W; Brownell, G L; Wellum, G R; Tolpin, E I

    1975-01-01

    The technique of boron neutron capture therapy in the treatment of cerebral gliomas depends upon the selective loading of the tumor with a 10B-enriched compound and subsequent irradiation of the brain with low-energy neutrons. The charged particles produced in the 10B (n,alpha) 7Li reaction have ranges in tissue of less than 10 mum so that the dose distribution closely follows the 10B distribution even to the cellular level. The effectiveness of this therapy procedure is dependent not only on the 10B compound but on the spectral characteristics of the neutron source as well. Hence, an optimization of these characteristics will increase the chances of therapeutic success. Transport calculations using a neutral particle transport code have been made to determine the dose-depth distributions within a simple head phantom for five different incident neutron beams. Comparison of these beams to determine their relative therapeutic efficacy was made by the use of a maximum useable depth criterion. In particular, with presently available compounds, the MIT reactor (MITR) therapy beam (a) is not inferior to a pure thermal neutron beam, (b) would be marginally improved if its gamma-ray contamination were eliminated, (c) is superior to a partially 10B-filtered MITR beam, and (d) produces a maximum useable depth which is strongly dependent upon the tumor-to-blood ratio of 10B concentrations and weakly dependent upon the absolute 10B concentration in tumor. A pure epithermal neutron beam with a mean energy of 37 eV is shown to have close to the optimal characteristics for boron neutron capture therapy. Futhermore, these optimal characteristics can be approximated by a judiciously D2O moderated and 10B-filtered 252Cf neutron source. This tailored 252Cf source would have at least a 1.5 cm greater maximum useable depth than the MITR therapy beam for realistic 10B concentrations. However, at least one gram of 252Cf would be needed to make this a practical therapy source. If the

  11. 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.

  12. Fiberoptics-Based Instrumentation for Storage Ring BeamDiagnostics

    SciTech Connect

    Byrd, John M.; De Santis, Stefano; Yin, Yan

    2007-04-18

    In several cases, coupling synchrotron light into opticalfibers can substantially facilitate the use of beam diagnosticinstrumentation, that measures longitudinal beam properties by detectingsynchrotron radiation. It has been discussed in [1]with some detail, howfiberoptics can bring the light at relatively large distances from theaccelerator, where a variety of devices can be used to measure beamproperties and parameters. Light carried on a fiber can be easilyswitched between instruments so that each one of them has 100 percent ofthe photons available, rather than just a fraction , when simultaneousmeasurements are not indispensable. From a more general point of view,once synchrotron light is coupled into the fiber, the vast array oftechniques and optoelectronic devices, developed by the telecommunicationindustry becomes available.In this paper we present the results of ourexperiments at the Advanced Light Source, where we tried to assess thechallenges and limitations of the coupling process and determine whatlevel of efficiency one can typically expect to achieve.

  13. Active Neutron and Gamma-Ray Instrumentation for In Situ Planetary Science Applications

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, A.; Lim, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

    2011-01-01

    We describe the development of an instrument capable of detailed in situ bulk geochemical analysis of the surface of planets, moons, asteroids, and comets. This instrument technology uses a pulsed neutron generator to excite the solid materials of a planet and measures the resulting neutron and gamma-ray emission with its detector system. These time-resolved neutron and gamma-ray data provide detailed information about the bulk elemental composition, chemical context, and density distribution of the soil within 50 cm of the surface. While active neutron scattering and neutron-induced gamma-ray techniques have been used extensively for terrestrial nuclear well logging applications, our goal is to apply these techniques to surface instruments for use on any solid solar system body. As described, experiments at NASA Goddard Space Flight Center use a prototype neutron-induced gamma-ray instrument and the resulting data presented show the promise of this technique for becoming a versatile, robust, workhorse technology for planetary science, and exploration of any of the solid bodies in the solar system. The detection of neutrons at the surface also provides useful information about the material. This paper focuses on the data provided by the gamma-ray detector.

  14. Planetary Geochemistry Techniques: Probing In-Situ with Neutron and Gamma Rays (PING) Instrument

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Burger, D.; Evans, L.; Floyd, S.; Lin, L.; McClanahan, T.; Nankung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

    2011-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument is a promising planetary science application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth. The objective of our technology development program at NASA Goddard Space Flight Center's (NASA/GSFC) Astrochemistry Laboratory is to extend the application of neutron interrogation techniques to landed in situ planetary composition measurements by using a 14 MeV Pulsed Neutron Generator (PNG) combined with neutron and gamma ray detectors, to probe the surface and subsurface of planetary bodies without the need to drill. We are thus working to bring the PING instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets.

  15. 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).

  16. Neutron background environment measured by the Mars Science Laboratory's Dynamic Albedo of Neutrons instrument during the first 100 sols

    NASA Astrophysics Data System (ADS)

    Jun, I.; Mitrofanov, I.; Litvak, M. L.; Sanin, A. B.; Kim, W.; Behar, A.; Boynton, W. V.; DeFlores, L.; Fedosov, F.; Golovin, D.; Hardgrove, C.; Harshman, K.; Kozyrev, A. S.; Kuzmin, R. O.; Malakhov, A.; Mischna, M.; Moersch, J.; Mokrousov, M.; Nikiforov, S.; Shvetsov, V. N.; Tate, C.; Tret'yakov, V. I.; Vostrukhin, A.

    2013-11-01

    Dynamic Albedo of Neutrons (DAN) instrument on board Mars Science Laboratory has been operating successfully since the landing and has been making measurements regularly along Curiosity's traverse at the surface. DAN measures thermal (E < 0.4 eV) and epithermal neutrons (0.4 eV < E < ~1 keV) while operating in two different modes: active and passive. The active mode uses a pulsed neutron generator (PNG) to study the geological characteristics of the subsurface. In the passive mode, DAN measures the background neutron environment. This paper presents results of measurements in the passive mode from landing through to sol 100 and provides an interpretation of the data based on extensive Monte Carlo simulations. The main observations are summarized as follows: (1) the thermal neutron counts vary strongly along the rover traverse while the epithermal counts do not show much variation; (2) the neutrons from the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) are a larger contributor to the DAN passive data than the Galactic Cosmic Ray (GCR)-induced neutrons; (3) for the MMRTG neutrons, both the thermal and the epithermal counts increase as a function of the subsurface water content; (4) on the other hand, for the GCR-induced neutrons, the thermal counts increase but the epithermal counts decrease as a function of the subsurface water content; and (5) relative contributions by the MMRTG and GCR to the DAN thermal neutron counts at the Rocknest site, where the rover was stationed from sol 59 to sol 100, are estimated to be ~60% and ~40%, respectively.

  17. Analysis of Neutron Production in Passively Scattered Ion-Beam Therapy.

    PubMed

    Heo, Seunguk; Yoo, Seunghoon; Song, Yongkeun; Kim, Eunho; Shin, Jaeik; Han, Soorim; Jung, Wongyun; Nam, Sanghee; Lee, Rena; Lee, Kitae; Cho, Sungho

    2016-11-24

    A new treatment facility for heavy ion therapy since 2010 was constructed. In the broad beam, a range shifter, ridge filter and multi leaf collimator (MLC) for the generation of the spread-out Bragg peak is used. In this case, secondary neutrons produced by the interactions of the ion field with beam-modifying devices (e.g. double-scattering system, beam shaping collimators and range compensators) are very important for patient safety. Therefore, these components must be carefully examined in the context of secondary neutron yield and associated secondary cancer risk. In this article, Monte Carlo simulation has been carried out with the FLUktuierende KAskade particle transport code, the fluence and distribution of neutron generation and the neutron dose equivalent from the broad beam components are compared using carbon and proton beams. As a result, it is confirmed that the yield of neutron production using a carbon beam from all components of the broad beam was higher than using a proton beam. The ambient dose by neutrons per heavy ion and proton ion from the MLC surface was 0.12-0.18 and 0.0067-0.0087 pSv, respectively, which shows that heavy ions generate more neutrons than protons. However, ambient dose per treatment 2 Gy, which means physical dose during treatment by ion beam, is higher than carbon beam because proton therapy needs more beam flux to make 2-Gy prescription dose. Therefore, the neutron production from the MLC, which is closed to the patient, is a very important parameter for patient safety.

  18. Dysprosium detector for neutron dosimetry in external beam radiotherapy

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  19. SU-E-T-168: Characterization of Neutrons From the TrueBeam Treatment Head

    SciTech Connect

    Sawkey, D; Svatos, M

    2015-06-15

    Purpose: Calculate neutron production and transport in the TrueBeam treatment head, as input for vault design and phantom dose calculations. Methods: A detailed model of the treatment head, including shielding components off the beam axis, was created from manufacturer’s engineering drawings. Simulations were done with Geant4 for the 18X, 15X, 10X and 10FFF beams, tuned to match measured dose distributions inside the treatment field. Particles were recorded on a 70 cm radius sphere surrounding the treatment head enabling input into simulations of vaults. Results: For the 18X beam, 11×10{sup 9} neutrons/MU were observed. The energy spectrum was a broad peak with average energy 0.37 MeV. With jaws closed, 48% of the neutrons were generated in the primary collimator, 18% in the jaws, 12% in the target, and 10% in the flattening filter. With wide open jaws, few neutrons were produced in the jaws and consequently total neutron production dropped to 8.5×10{sup 9} neutrons/MU. Angular distributions were greatest along the beam axis (12×10{sup 9} neutrons/MU/sr, within 2 deg of the beam axis) and antiparallel to the beam axis (7×10{sup 9} neutrons/MU/sr). Peaks were observed in the neutron energy spectrum, corresponding to elastic scattering resonances in the shielding materials. Neutron production was lower for the other beams studied: 4.1×10{sup 9} neutrons/MU for 15X, 0.38×10{sup 9} neutrons/MU for 10X, and 0.22×10{sup 9} neutrons/MU for 10FFF. Despite dissimilar treatment head geometries and materials, the neutron production and energy spectrum were similar to those reported for Clinac accelerators. Conclusion: Detailed neutron production and leakage calculations for the TrueBeam treatment head were done. Unlike other studies, results are independent of the surrounding vault, enabling vault design calculations.

  20. Measuring subsurface water distribution using the Dynamic Albedo of Neutrons instrument on Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Busch, Michael W.; Aharonson, Oded

    2008-07-01

    The Dynamic Albedo of Neutrons (DAN) instrument, a neutron scattering instrument currently being constructed by IKI, is a component of the science payload of the 2009 Mars Science Laboratory (MSL) mission. Based on simulations using the Monte-Carlo N-Particle Extended (MCNPX) particle physics code, DAN is able to measure bulk water content and to detect variations in water concentration up to ˜50 cm beneath the ground surface, assuming perfect detector performance. Data from DAN, combined with measurements from other instruments on MSL, allow derivation of profiles of water content to a depth of ˜15 cm.

  1. Estimating Background and Lunar Contribution to Neutrons Detected by the Lunar Reconnaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) Instrument

    NASA Astrophysics Data System (ADS)

    Livengood, T. A.; Mitrofanov, I. G.; Chin, G.; Boynton, W. V.; Evans, L. G.; Litvak, M. L.; McClanahan, T. P.; Sagdeev, R.; Sanin, A. B.; Starr, R. D.; Su, J. J.

    2014-12-01

    The fraction of hydrogen-bearing species embedded in planetary regolith can be determined from the ratio between measured epithermal neutron leakage flux and the flux measured from similar dry regolith. The Lunar Reconnaissance Orbiter (LRO) spacecraft is equipped with the Lunar Exploration Neutron Detector (LEND) instrument to measure embedded hydrogen in the Moon's polar regions and elsewhere. We have investigated the relative contribution of lunar and non-lunar (spacecraft-sourced) neutrons by modeling maps of the measured count rate from three of the LEND detector systems using linear combinations of maps compiled from the Lunar Prospector Neutron Spectrometer (LPNS) and the LEND detectors, demonstrating that the two systems are compatible and enabling reference signal to be inferred to enable detecting hydrogen and hydrogen-bearing volatiles. The pole-to-equator contrast ratio in epithermal neutrons indicates that the average concentration of hydrogen in the Moon's polar regolith above 80° north or south latitude is ~110 ppmw, or 0.10±0.01 wt% water-equivalent hydrogen. Above 88° north or south, the concentration increases to ~140 ppmw, or 0.13±0.02 wt% water-equivalent hydrogen. Nearly identical suppression of neutron flux at both the north and south poles, despite differences in topography and distribution of permanently-shadowed regions, supports the contention that hydrogen is broadly distributed in the polar regions and increasingly concentrated approaching the poles. Similarity in the degree of neutron suppression in low-energy and high-energy epithermal neutrons suggests that the hydrogen fraction is relatively uniform with depth down to ~1 m; the neutron leakage flux is insensitive to greater depth.

  2. Performance of Current-Mode Ion Chambers as Beam Monitors in a Pulsed Cold Neutron Beam for the NPDGamma experiment

    NASA Astrophysics Data System (ADS)

    Gillis, R. Chad

    2006-10-01

    The NPDGamma collaboration has built and commissioned an apparatus to measure the parity-violating gamma asymmetry A in the low energy np capture process n+p->d+ γ. The asymmetry in question is a 10-8 correlation between the spin of the incident (polarized) neutron and the outgoing 2.2 MeV gamma ray. A set of purpose-built, 3He-filled ionization chambers read out in current mode is used to monitor the incident neutron flux, the beam polarization, and the transmission of the liquid para-hydrogen target during the NPDGamma measurements. As will be described in the talk, these beam monitors are simple, reliable, low-noise detectors that have performed excellently for NPDGamma. We have verified that the beam monitor signals can be interpreted to reproduce the known time-of-flight dependence of beam flux from the LANSCE pulsed cold neutron source, and that the neutron beam polarization can be measured at the 2% level from direct measurements of the transmission of the beam through the beam polarizer.

  3. Improvement of a p(65)+Be neutron beam for therapy at Cyclone, Louvain-la-Neuve.

    PubMed

    Vynckier, S; Pihet, P; Flémal, J M; Meulders, J P; Wambersie, A

    1983-06-01

    The variable energy cyclotron of the Catholic University of Louvain is used to produce intense neutron beams for neutron therapy purposes. As a first step, neutrons were produced by bombarding a Be target with 50 MeV deuterons; at present they are produced by 65 MeV protons. This paper describes the improvements to the target system. A new (17 mm) Be target together with the old (10 mm) Be target are inserted in a movable support which allows the production of neutrons either by 65 MeV protons or by 50 MeV deuterons. Both targets can be removed for proton beam therapy. The dosimetric characteristics of the p(65)+Be and d(50)+Be neutron beams are compared: dose rate, gamma-contribution, depth dose and room activation.

  4. The upgraded cold neutron triple-axis spectrometer FLEXX - enhanced capabilities by new instrumental options

    NASA Astrophysics Data System (ADS)

    Habicht, Klaus; Lucía Quintero-Castro, Diana; Toft-Petersen, Rasmus; Kure, Mathias; Mäde, Lucas; Groitl, Felix; Le, Manh Duc

    2015-01-01

    The upgrade of the cold neutron triple axis spectrometer FLEXX, a work-horse instrument for inelastic neutron scattering matching the sample environment capabilities at Helmholtz-Zentrum Berlin, has been successfully accomplished. Experiments confirmed an order of magnitude gain in flux now allowing for intensity demanding options to be fully exploited at FLEXX. In this article, we describe the layout and design of two newly available FLEXX instrument options in detail. The new Heusler analyzer gives an increase of the detected polarized neutron flux due to its superior focusing properties, significantly improving the feasibility of future polarized and neutron resonance spin echo experiments. The MultiFLEXX option provides simultaneous access to large regions in wavevector and energy space for inelastic excitations thus adding mapping capabilities to the spectrometer.

  5. 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

  6. A novel design of beam shaping assembly to use D-T neutron generator for BNCT.

    PubMed

    Kasesaz, Yaser; Karimi, Marjan

    2016-12-01

    In order to use 14.1MeV neutrons produced by d-T neutron generators, two special and novel Beam Shaping Assemblies (BSA), including multi-layer and hexagonal lattice have been suggested and the effect of them has been investigated by MCNP4C Monte Carlo code. The results show that the proposed BSA can provide the qualified epithermal neutron beam for BNCT. The final epithermal neutron flux is about 6e9 n/cm2.s. The final proposed BSA has some different advantages: 1) it consists of usual and well-known materials (Pb, Al, Fluental and Cd); 2) it has a simple geometry; 3) it does not need any additional gamma filter; 4) it can provide high flux of epithermal neutrons. As this type of neutron source is under development in the world, it seems that they can be used clinically in a hospital considering the proposed BSA.

  7. 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.

  8. A neutron imaging device for sample alignment in a pulsed neutron scattering instrument

    SciTech Connect

    Grazzi, F.; Scherillo, A.; Zoppi, M.

    2009-09-15

    A neutron-imaging device for alignment purposes has been tested on the INES beamline at ISIS, the pulsed neutron source of Rutherford Appleton Laboratory (U.K.). Its use, in conjunction with a set of movable jaws, turns out extremely useful for scattering application to complex samples where a precise and well-defined determination of the scattering volume is needed.

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  10. 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.

  11. 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.

  12. Bragg optics computer codes for neutron scattering instrument design

    SciTech Connect

    Popovici, M.; Yelon, W.B.; Berliner, R.R.; Stoica, A.D.

    1997-09-01

    Computer codes for neutron crystal spectrometer design, optimization and experiment planning are described. Phase space distributions, linewidths and absolute intensities are calculated by matrix methods in an extension of the Cooper-Nathans resolution function formalism. For modeling the Bragg reflection on bent crystals the lamellar approximation is used. Optimization is done by satisfying conditions of focusing in scattering and in real space, and by numerically maximizing figures of merit. Examples for three-axis and two-axis spectrometers are given.

  13. Investigation of properties of the TIARA neutron beam facility of importance for calibration applications.

    PubMed

    Shikaze, Y; Tanimura, Y; Saegusa, J; Tsutsumi, M; Yamaguchi, Y; Uchita, Y

    2007-01-01

    Evaluation of the properties for quasi-monoenergetic neutron calibration fields of high energies more than 20 MeV at TIARA is proceeding for development of the field. Among the properties needed for the development as the standard calibration field, we report on measurement of the neutron beam profile using an imaging plate with a polyethylene converter and on estimation of the contribution of scattered neutrons into the irradiation field based on pulse height distribution at various off-beam positions measured using an organic liquid scintillation detector.

  14. Neutron monitoring systems including gamma thermometers and methods of calibrating nuclear instruments using gamma thermometers

    DOEpatents

    Moen, Stephan Craig; Meyers, Craig Glenn; Petzen, John Alexander; Foard, Adam Muhling

    2012-08-07

    A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5.times.10.sup.-1 seconds and less than 5.times.10.sup.5 seconds.

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

    NASA Astrophysics Data System (ADS)

    Yurevich, Vladimir

    2016-09-01

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

  16. 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.

  17. 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.

  18. 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.

  19. Analyzing of the Die Away Curve of the Msl Dynamic Albedo of Neutrons (dan) Instrument

    NASA Astrophysics Data System (ADS)

    Varenikov, A.; Jun, I.; Litvak, M. L.

    2012-12-01

    The Dynamic Albedo of Neutrons (DAN) is flown on board Mars Science Laboratory (MSL) to provide measurements of the dynamic albedo of thermal and epithermal neutrons induced by a pulse 14 MeV neutron generator. The DAN instrument consists of pulse neutron generator (DAN/PNG) electrically and logically combined with neutron detection system (DAN/DE). The major science objective of DAN instrument is to detect and provide quantitative estimates of the hydrogen content in the sub-surface layer of Mars. The amplitude and shape of the die-away time profile strongly depends on the content, depth and geometry distribution of water ice/bound layer. Die-away curves of thermal neutrons are simulated using a Monte Carlo transport code (MCNPX) for a homogeneous model of regolith with different contents of water. Tw different cases were considered in the initial simulations: single layered model and double layered model. In the first case, the sub-surface is modelled as a homogeneous single layer with different water contents. The preliminary results show that DAN could measure the water content as low as 0.1-0.2 weight %. The second case includes the sub-surface described by two layers. It is used to evaluate the DAN sensitivity to detect water depth (where the bottom layer is richer in water content than the upper layer).

  20. 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.).

  1. 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.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  4. Experiments with neutron beams for the astrophysical s process

    NASA Astrophysics Data System (ADS)

    Lederer, C.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Duran, I.; Dressler, R.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Korschinek, G.; Krtička, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Leeb, H.; Leong, L. S.; Losito, R.; Mallick, A.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondalaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Pignatari, M.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Robles, M. S.; Roman, F.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiβ, C.; Wright, T.; Žugec, P.

    2016-01-01

    Neutron capture cross sections are the key nuclear physics input to study the slow neutron capture process, which is responsible for forming about half of the elemental abundances above Fe. Stellar neutron capture cross section can be measured by the time-of-flight technique, or by activation. Both techniques will be discussed and recent experiments in the Fe/Ni mass region will be presented.

  5. Neutron lifetime measurement with pulsed beam at J- PARC: TPC and DAQ

    NASA Astrophysics Data System (ADS)

    Yamada, Takahito; Katayama, Ryo; Higashi, Nao; Yokoyama, Harumichi; Sumino, Hirochika; Yamashita, Satoru; Sakakibara, Risa; Sugino, Tomoaki; Kitaguchi, Masaaki; Hirota, Katsuya; Shimizu, Hirohiko M.; Tanaka, Genki; Sumi, Naoyukio; Otono, Hidetoshi; Yoshioka, Tamaki; Kitahara, Ryunosuke; Iwashita, Yoshihisa; Oide, Hideyuki; Shima, Tatsushi; Seki, Yoshichika; Mishima, Kenji; Taketani, Kaoru; Ino, Takashi; NOP Collaboration

    2014-09-01

    The neutron lifetime is an important parameter for Big Bang nucleosynthesis (BBN). The best neutron lifetime measurements have uncertainties at the 0.1% level; however, they differ by 3.8 sigma. In order to resolve this discrepancy, we plan to measure the neutron lifetime using a method originally developed by Kossakowski et al. which is different from the other 0.1% accuracy experiments. In our method, which uses a pulsed cold neutron beam at J-PARC, the electrons from the beta decay of the neutron are detected with a time projection chamber (TPC). A small amount of 3He is added to the gas mixture in order to simultaneously measure the neutron flux. We report on the recent upgrade of the TPC and the Data Acquisition System which were used to take data during the period of February-June 2014.

  6. Preliminary treatment planning and dosimetry for a clinical trial of neutron capture therapy using a fission converter epithermal neutron beam.

    PubMed

    Kiger, W S; Lu, X Q; Harling, O K; Riley, K J; Binns, P J; Kaplan, J; Patel, H; Zamenhof, R G; Shibata, Y; Kaplan, I D; Busse, P M; Palmer, M R

    2004-11-01

    A Phase I/II clinical trial of neutron capture therapy (NCT) was conducted at Harvard-MIT using a fission converter epithermal neutron beam. This epithermal neutron beam has nearly ideal performance characteristics (high intensity and purity) and is well-suited for clinical use. Six glioblastoma multiforme (GBM) patients were treated with NCT by infusion of the tumor-selective amino acid boronophenylalanine-fructose (BPA-F) at a dose of 14.0 g/m(2) body surface area over 90 min followed by irradiation with epithermal neutrons. Treatments were planned using NCTPlan and an accelerated version of the Monte Carlo radiation transport code MCNP 4B. Treatments were delivered in two fractions with two or three fields. Field order was reversed between fractions to equalize the average blood boron concentration between fields. The initial dose in the dose escalation study was 7.0 RBEGy, prescribed as the mean dose to the whole brain volume. This prescription dose was increased by 10% to 7.7 RBEGy in the second cohort of patients. A pharmacokinetic model was used to predict the blood boron concentration for determination of the required beam monitor units with good accuracy; differences between prescribed and delivered doses were 1.5% or less. Estimates of average tumor doses ranged from 33.7 to 83.4 RBEGy (median 57.8 RBEGy), a substantial improvement over our previous trial where the median value of the average tumor dose was 25.8 RBEGy.

  7. 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.

  8. Performance of orbital neutron instruments for spatially resolved hydrogen measurements of airless planetary bodies.

    PubMed

    Lawrence, David J; Elphic, Richard C; Feldman, William C; Funsten, Herbert O; Prettyman, Thomas H

    2010-03-01

    Orbital neutron spectroscopy has become a standard technique for measuring planetary surface compositions from orbit. While this technique has led to important discoveries, such as the deposits of hydrogen at the Moon and Mars, a limitation is its poor spatial resolution. For omni-directional neutron sensors, spatial resolutions are 1-1.5 times the spacecraft's altitude above the planetary surface (or 40-600 km for typical orbital altitudes). Neutron sensors with enhanced spatial resolution have been proposed, and one with a collimated field of view is scheduled to fly on a mission to measure lunar polar hydrogen. No quantitative studies or analyses have been published that evaluate in detail the detection and sensitivity limits of spatially resolved neutron measurements. Here, we describe two complementary techniques for evaluating the hydrogen sensitivity of spatially resolved neutron sensors: an analytic, closed-form expression that has been validated with Lunar Prospector neutron data, and a three-dimensional modeling technique. The analytic technique, called the Spatially resolved Neutron Analytic Sensitivity Approximation (SNASA), provides a straightforward method to evaluate spatially resolved neutron data from existing instruments as well as to plan for future mission scenarios. We conclude that the existing detector--the Lunar Exploration Neutron Detector (LEND)--scheduled to launch on the Lunar Reconnaissance Orbiter will have hydrogen sensitivities that are over an order of magnitude poorer than previously estimated. We further conclude that a sensor with a geometric factor of approximately 100 cm(2) Sr (compared to the LEND geometric factor of approximately 10.9 cm(2) Sr) could make substantially improved measurements of the lunar polar hydrogen spatial distribution.

  9. Performance of Orbital Neutron Instruments for Spatially Resolved Hydrogen Measurements of Airless Planetary Bodies

    PubMed Central

    Elphic, Richard C.; Feldman, William C.; Funsten, Herbert O.; Prettyman, Thomas H.

    2010-01-01

    Abstract Orbital neutron spectroscopy has become a standard technique for measuring planetary surface compositions from orbit. While this technique has led to important discoveries, such as the deposits of hydrogen at the Moon and Mars, a limitation is its poor spatial resolution. For omni-directional neutron sensors, spatial resolutions are 1–1.5 times the spacecraft's altitude above the planetary surface (or 40–600 km for typical orbital altitudes). Neutron sensors with enhanced spatial resolution have been proposed, and one with a collimated field of view is scheduled to fly on a mission to measure lunar polar hydrogen. No quantitative studies or analyses have been published that evaluate in detail the detection and sensitivity limits of spatially resolved neutron measurements. Here, we describe two complementary techniques for evaluating the hydrogen sensitivity of spatially resolved neutron sensors: an analytic, closed-form expression that has been validated with Lunar Prospector neutron data, and a three-dimensional modeling technique. The analytic technique, called the Spatially resolved Neutron Analytic Sensitivity Approximation (SNASA), provides a straightforward method to evaluate spatially resolved neutron data from existing instruments as well as to plan for future mission scenarios. We conclude that the existing detector—the Lunar Exploration Neutron Detector (LEND)—scheduled to launch on the Lunar Reconnaissance Orbiter will have hydrogen sensitivities that are over an order of magnitude poorer than previously estimated. We further conclude that a sensor with a geometric factor of ∼ 100 cm2 Sr (compared to the LEND geometric factor of ∼ 10.9 cm2 Sr) could make substantially improved measurements of the lunar polar hydrogen spatial distribution. Key Words: Planetary instrumentation—Planetary science—Moon—Spacecraft experiments—Hydrogen. Astrobiology 10, 183–200. PMID:20298147

  10. Neutron Generation from Laser-Accelerated Ion Beams: Use of Alternative Deuteron-Rich Targets for Improved Neutron Yield and Control of Neutron Spectra

    NASA Astrophysics Data System (ADS)

    Albright, B. J.; Yin, L.; Favalli, A.

    2016-10-01

    Laser-ion-beam generation in the break-out afterburner (BOA) acceleration regime has been modeled for several deuteron-rich solid-density targets using the VPIC particle-in-cell code. Monte Carlo modeling of the transport of these beams in a beryllium converter in a pitcher-catcher neutron source configuration shows significant increases in neutron yields may be achievable through judicious choices of laser target material. Additionally, species-separation dynamics in some target materials during the BOA ion acceleration phase can be exploited to control the shapes of the neutron spectra. Work performed under the auspices of the U.S. DOE by the LANS, LLC, Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396. Funding provided by the Los Alamos National Laboratory Directed Research and Development Program.

  11. 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.

  12. Measurement and simulation of the response function of time of flight enhanced diagnostics neutron spectrometer for beam ion studies at EAST tokamak

    NASA Astrophysics Data System (ADS)

    Peng, X. Y.; Chen, Z. J.; Zhang, X.; Du, T. F.; Hu, Z. M.; Ge, L. J.; Zhang, Y. M.; Sun, J. Q.; Gorini, G.; Nocente, M.; Tardocchi, M.; Hu, L. Q.; Zhong, G. Q.; Pu, N.; Lin, S. Y.; Wan, B. N.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.

    2016-11-01

    The 2.5 MeV TOFED (Time-Of-Flight Enhanced Diagnostics) neutron spectrometer with a double-ring structure has been installed at Experimental Advanced Superconducting Tokamak (EAST) to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas. This work describes the response function of the TOFED spectrometer, which is evaluated for the fully assembled instrument in its final layout. Results from Monte Carlo simulations and dedicated experiments with pulsed light sources are presented and used to determine properties of light transport from the scintillator. A GEANT4 model of the TOFED spectrometer was developed to calculate the instrument response matrix. The simulated TOFED response function was successfully benchmarked against measurements of the time-of-flight spectra for quasi-monoenergetic neutrons in the energy range of 1-4 MeV. The results are discussed in relation to the capability of TOFED to perform beam ion studies on EAST.

  13. Measurement and simulation of the response function of time of flight enhanced diagnostics neutron spectrometer for beam ion studies at EAST tokamak.

    PubMed

    Peng, X Y; Chen, Z J; Zhang, X; Du, T F; Hu, Z M; Ge, L J; Zhang, Y M; Sun, J Q; Gorini, G; Nocente, M; Tardocchi, M; Hu, L Q; Zhong, G Q; Pu, N; Lin, S Y; Wan, B N; Li, X Q; Zhang, G H; Chen, J X; Fan, T S

    2016-11-01

    The 2.5 MeV TOFED (Time-Of-Flight Enhanced Diagnostics) neutron spectrometer with a double-ring structure has been installed at Experimental Advanced Superconducting Tokamak (EAST) to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas. This work describes the response function of the TOFED spectrometer, which is evaluated for the fully assembled instrument in its final layout. Results from Monte Carlo simulations and dedicated experiments with pulsed light sources are presented and used to determine properties of light transport from the scintillator. A GEANT4 model of the TOFED spectrometer was developed to calculate the instrument response matrix. The simulated TOFED response function was successfully benchmarked against measurements of the time-of-flight spectra for quasi-monoenergetic neutrons in the energy range of 1-4 MeV. The results are discussed in relation to the capability of TOFED to perform beam ion studies on EAST.

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

    PubMed

    Sakurai, Yoshinori; Ono, Koji

    2007-12-21

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

  15. A Unique Outside Neutron and Gamma Ray Instrumentation Development Test Facility at NASA's Goddard Space Flight Center

    NASA Technical Reports Server (NTRS)

    Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Parsons, A.; Schweitzer, J.; Starr, R.; Trombka, J.

    2010-01-01

    An outside neutron and gamma ray instrumentation test facility has been constructed at NASA's Goddard Space Flight Center (GSFC) to evaluate conceptual designs of gamma ray and neutron systems that we intend to propose for future planetary lander and rover missions. We will describe this test facility and its current capabilities for operation of planetary in situ instrumentation, utilizing a l4 MeV pulsed neutron generator as the gamma ray excitation source with gamma ray and neutron detectors, in an open field with the ability to remotely monitor and operate experiments from a safe distance at an on-site building. The advantage of a permanent test facility with the ability to operate a neutron generator outside and the flexibility to modify testing configurations is essential for efficient testing of this type of technology. Until now, there have been no outdoor test facilities for realistically testing neutron and gamma ray instruments planned for solar system exploration

  16. Fine Resolution Neutron Detector for ExoMars Trace Gas Orbiter. Instrument and science goals.

    NASA Astrophysics Data System (ADS)

    Malakhov, Alexey; Litvak, Maxim; Kozyrev, S. Alexander; Tretiyakov, Vladislav; Sanin, Anton; Mokrousov, Maxim; Vostrukhin, Andrey; Golovin, Dmitry; Semkova, Jordanka; Dachev, Tsvetan; Malchev, Stefan; Tomov, Borislav; Matviichuk, Yury; Dimitrov, Plamen; Koleva, Rositza; Mitrofanov, Igor; F

    Fine Resolution Neutron Detector (FREND) will measure neutrons of different energy ranges, charged particles and radiation environment onboard ExoMars 2016 Trace Gas Orbiter spacecraft. The instrument contains a set of (3) He detectors for epithermal neutrons and a scintillation crystal for high-energy neutrons and charged particles measurements. Dosimeter module will perform dose and particle flux monitoring. The instrument also contains a collimation module that narrows 3He counters’ and scintillator’s field of view to a narrow spot on the surface of Mars of about 40 km. FREND will be the first experiment to perform high resolution hydrogen mapping of the Martian surface. Current hydrogen maps obtained by HEND instrument onboard Mars Odyssey provide only 300km spatial resolution. Improved data from FREND will be very valuable for further exploration missions in terms of landing sites selection, as well as enable us to better understand Martian geology, seasonal CO _{2} cycles and planet’s history. Radiation environment data from dosimeter module on Martian orbit will provide improved knowledge for future human exploration as well as perform solar particle events monitoring.

  17. The Probing In-Situ With Neutron and Gamma Rays (PING) Instrument for Planetary Composition Measurements

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.

    2012-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument (formerly named PNG-GRAND) [I] experiment is an innovative application of the active neutron-gamma ray technology successfully used in oil field well logging and mineral exploration on Earth over many decades. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring PING to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets and measure their bulk surface and subsurface elemental composition without the need to drill into the surface. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions. While orbital measurements can map a planet, they have low spatial and elemental sensitivity due to the low surface gamma ray emission rates reSUlting from using cosmic rays as an excitation source, PING overcomes this limitation in situ by incorporating a powerful neutron excitation source that permits significantly higher elemental sensitivity elemental composition measurements. PING combines a 14 MeV deuterium-tritium Pulsed Neutron Generator (PNG) with a gamma ray spectrometer and two neutron detectors to produce a landed instrument that can determine the elemental composition of a planet down to 30 - 50 cm below the planet's surface, The penetrating nature of .5 - 10 MeV gamma rays and 14 MeV neutrons allows such sub-surface composition measurements to be made without the need to drill into or otherwise disturb the planetary surface, thus greatly simplifying the lander design, We are cun'ently testing a PING prototype at a unique outdoor neutron instrumentation test facility at NASA/GSFC that provides two large (1.8 m x 1.8 m x ,9 m) granite and basalt test formations placed outdoors in an empty field, Since an independent trace elemental analysis has been performed on both these

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Relative biological effects of neutron mixed-beam irradiation for boron neutron capture therapy on cell survival and DNA double-strand breaks in cultured mammalian cells

    PubMed Central

    Okumura, Kakuji; Kinashi, Yuko; Kubota, Yoshihisa; Kitajima, Erika; Okayasu, Ryuichi; Ono, Koji; Takahashi, Sentaro

    2013-01-01

    Understanding the biological effects of neutron mixed-beam irradiation used for boron neutron capture therapy (BNCT) is important in order to improve the efficacy of the therapy and to reduce side effects. In the present study, cell viability and DNA double-strand breaks (DNA-DSBs) were examined in Chinese hamster ovary cells (CHO-K1) and their radiosensitive mutant cells (xrs5, Ku80-deficient), following neutron mixed-beam irradiation for BNCT. Cell viability was significantly impaired in the neutron irradiation groups compared to the reference gamma-ray irradiation group. The relative biological effectiveness for 10% cell survival was 3.3 and 1.2 for CHO-K1 and xrs5 cells, respectively. There were a similar number of 53BP1 foci, indicators of DNA-DSBs, in the neutron mixed-beam and the gamma-ray groups. In addition, the size of the foci did not differ between groups. However, neutron mixed-beam irradiation resulted in foci with different spatial distributions. The foci were more proximal to each other in the neutron mixed-beam groups than the gamma-ray irradiation groups. These findings suggest that neutron beams may induce another type of DNA damage, such as clustered DNA-DSBs, as has been indicated for other high-LET irradiation. PMID:22966174

  3. Wedge factor dependence with depth and field size for fast neutron beams.

    PubMed

    Popescu, Alina; Risler, Ruedi

    2003-07-21

    The dependence of the wedge factors (WFs) on field size (FS) and depth for a fast neutron beam has been investigated. In a previous study (Popescu et al 1999 Med. Phys. 26 541), a method was presented that allows a simple and accurate way of calculating the wedge-factor dependence on FS and depth in the case of a photon beam. The validity of a similar approach is tested in the present study for neutron beam dosimetry. The clinical neutron therapy system at the University of Washington (UW) has a flattening filter assembly consisting of two filters: a small field filter and a large field filter. Despite this complication, the approach presented in Popescu et al (1999 Med. Phys. 26 541) can be used to describe the WF dependence on FS and depth (d).

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  5. 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.

  6. The Berkeley Instrumental Neutron Generator (BINGE) for 40Ar/39Ar geochronology

    NASA Astrophysics Data System (ADS)

    Renne, P. R.; Becker, T. A.; Bernstein, L.; Firestone, R. B.; Kirsch, L.; Leung, K. N.; Rogers, A.; Van Bibber, K.; Waltz, C.

    2014-12-01

    The Berkeley Instrumental Neutron Generator (BINGE) facility is the product of a consortium involving the Berkeley Geochronology Center (BGC), the U.C. Berkeley Nuclear Engineering Dept. (UCB/NE), and Lawrence Berkeley (LBNL) and Lawrence Livermore (LLNL) National Labs. BINGE was initially designed (and funded by NSF) for 40Ar/39Ar geochronology. BINGE uses a plasma-based deuteron ion source and a self-loading Ti-surfaced target to induce deuteron-deuterium (DD) fusion via the reaction 2H(d,n)3He, producing 2.45 MeV neutrons. The limited neutron energy spectrum is aimed at reducing recoil effects, interfering nuclear reactions, and unwanted radioactive byproducts, all of which are undesirable consequences of conventional irradiation with 235U fission spectrum neutrons. Minimization of interfering reactions such as 40Ca(n,na)36Ar greatly reduces penalties for over-irradiation, enabling improved signal/background measurement of e.g. 39Ar. BINGE will also be used for a variety of nuclear physics and engineering experiments that require a high flux of monoenergetic neutrons. Neutron energies lower than 2.45 MeV can be obtained via irradiation ports within and external to polyethylene shielding. Initial commissioning produced a neutron flux of 108 n/sec/cm2 at 1 mA source current and 100 kV anode voltage, as expected. When scaled up to the 1 A source current as planned, this indicates that BINGE will achieve the design objective neutron flux of 1011 n/sec/cm2. Further progress towards this goal will be reported. Supported by NSF (grant #EAR-0960138), BGC, UCB/NE, University of California Office of the President, and DOE through LLNL under contract #DE-AC52-07NA27344 and LBNL under contract #DE-AC02-05CH11231.

  7. 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.

  8. 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.

  9. 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.

  10. Nuclear analytical techniques with neutron beams at the Univ. of Texas at Austin

    SciTech Connect

    Uenlue, K.; Wehring, B.W.

    1996-12-31

    Neutron beams produced by nuclear research reactors can be used for analytical chemical analysis by measuring nuclear radiation produced by neutron capture. Prompt gamma activation analysis (PGAA) and neutron depth profiling (NDP) are two such analytical techniques. For the last three decades, these techniques have been applied at a number of research reactors around the world. Within the last 4 yr, we have developed NDP and PGAA facilities at The University of Texas at Austin research reactor, a 1-MW TRIGA Mark II reactor. Brief descriptions of the facilities and summaries of activities for these analytical techniques at the University of Texas at Austin are provided in this paper.

  11. Monte-Carlo simulations of a high-resolution neutron TOF instrument

    NASA Astrophysics Data System (ADS)

    Bernhardt, Ph; Demmel, F.; Magerl, A.

    2000-03-01

    It is proposed to build a flexible, high-resolution time-of-flight diffractometer and spectrometer at the new reactor FRM II of the Technische Universität München. To optimize the layout of individual components and to estimate the performance of the entire instrument, we have made analytical calculations and Monte-Carlo simulations mainly with “McStas”, programmed by RISØ, Denmark. MC simulation routines for neutron devices like curved guides, disc- and Fermi choppers have been added. The influence of curved guides in neutron phase space has been developed and will be presented. Line shapes of neutron pulses and transmission have been studied for a Fermi chopper with straight slits and will be compared with the results of simulation.

  12. A method for using neutron elastic scatter to create a variable energy neutron beam from a nearly monoenergetic neutron source

    NASA Astrophysics Data System (ADS)

    Whetstone, Z. D.; Kearfott, K. J.

    2015-07-01

    This work describes preliminary investigation into the design of a compact, portable, variable energy neutron source. The proposed method uses elastic neutron scatter at specific angles to reduce the energy of deuterium-deuterium or deuterium-tritium (D-T) neutrons. The research focuses on D-T Monte Carlo simulations, both in idealized and more realistic scenarios. Systematic uncertainty of the method is also analyzed. The research showed promise, but highlighted the need for discrimination of multiply-scattered neutrons, either through a pulsed generator or associated particle imaging.

  13. Active Neutron and Gamma Ray Instrumentation for In Situ Planetary Science Applications

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Schweitzer, J.; Starr, R.; Trombka, J.

    2010-01-01

    The Pulsed Neutron Generator-Gamma Ray And Neutron Detectors (PNG-GRAND) experiment is an innovative application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA-GSFC) is to bring the PNG-GRAND instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Menus, asteroids, comets and the satellites of the outer planets. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions and, especially its the case of the Mars Odyssey GRS, have contributed detailed maps of the elemental composition over the entire surface of Mars. However, orbital gamma ray measurements have low spatial sensitivity (100's of km) due to their low surface emission rates from cosmic rays and subsequent need to be averaged over large surface areas. PNG-GRAND overcomes this impediment by incorporating a powerful neutron excitation source that permits high sensitivity surface and subsurface measurements of bulk elemental compositions. PNG-GRAND combines a pulsed neutron generator (PNG) with gamma ray and neutron detectors to produce a landed instrument to determine subsurface elemental composition without needing to drill into a planet's surface a great advantage in mission design. We are currently testing PNG-GRAND prototypes at a unique outdoor neutron instrumentation test facility recently constructed at NASA/GSFC that consists of a 2 m x 2 in x 1 m granite structure placed outdoors in an empty field. Because an independent trace elemental analysis has been performed on the material, this granite sample is a known standard with which to compare both Monte Carlo simulations and our experimentally measured elemental composition data. We will present data from operating PNG-GRAND in various experimental configurations on a

  14. Monitoring a liquid waste stream with a delayed-neutron instrument

    SciTech Connect

    Rinard, P.M.; Van Lyssel, T.; Kroncke, K.E.; Schneider, C.M.; Bourret, S.C.

    1989-01-01

    A flowing raffinate stream is to be continuously assayed by a delayed-neutron instrument to detect concentrations of {sup 235}U that could cause a criticality problem in a holding tank. The instrument is to assay a concentration of 0.034 (g {sup 235}U)/L in 100 s with a precision of 10% (1 {sigma}) and to operate unattended for a few months at a time, so it can detect and adjust for changes in the neutron background, the flow rate, and for electronic drifts and malfunctions. In laboratory tests with conditions slightly different from what may be found in the plant, repeated assays on a solution with 0.034 (g {sup 235}U)/L flowing at 80 L/h through the 2-L assay tank had relative precisions of 9-11%. 5 refs., 5 figs.

  15. 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.

  16. 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.

  17. The MICE Muon Beam on ISIS and the beam-line instrumentation of the Muon Ionization Cooling Experiment

    SciTech Connect

    Bogomilov, M.; et al.

    2012-05-01

    The international Muon Ionization Cooling Experiment (MICE), which is under construction at the Rutherford Appleton Laboratory (RAL), will demonstrate the principle of ionization cooling as a technique for the reduction of the phase-space volume occupied by a muon beam. Ionization cooling channels are required for the Neutrino Factory and the Muon Collider. MICE will evaluate in detail the performance of a single lattice cell of the Feasibility Study 2 cooling channel. The MICE Muon Beam has been constructed at the ISIS synchrotron at RAL, and in MICE Step I, it has been characterized using the MICE beam-instrumentation system. In this paper, the MICE Muon Beam and beam-line instrumentation are described. The muon rate is presented as a function of the beam loss generated by the MICE target dipping into the ISIS proton beam. For a 1 V signal from the ISIS beam-loss monitors downstream of our target we obtain a 30 KHz instantaneous muon rate, with a neglible pion contamination in the beam.

  18. Performance characteristics of the new detector array for the SANS2d instrument on the ISIS spallation neutron source

    NASA Astrophysics Data System (ADS)

    Duxbury, D.; Heenan, R.; McPhail, D.; Raspino, D.; Rhodes, N.; Rogers, S.; Schooneveld, E.; Spill, E.; Terry, A.

    2014-12-01

    The performance of the new position sensitive neutron detector arrays of the Small Angle Neutron Scattering (SANS) instrument SANS2d is described. The SANS2d instrument is one of the seven instruments currently available for users on the second target station (TS2) of the ISIS spallation neutron source. Since the instrument became operational in 2009 it has used two one metre square multi-wire proportional detectors (MWPC). However, these detectors suffer from a low count rate capability, are easily damaged by excess beam and are then expensive to repair. The new detector arrays each consist of 120 individual position sensitive detector tubes, filled with 15 bar of 3He. Each of the tubes is one metre long and has a diameter of 8mm giving a detector array with an overall area of one square metre. Two such arrays have been built and installed in the SANS2d vacuum tank where they are currently taking user data. For SANS measurements operation of the detector within a vacuum is essential in order to reduce air scattering. A novel, fully engineered approach has been utilised to ensure that the high voltage connections and preamps are located inside the SANS2d vacuum tank at atmospheric pressure, within air tubes and air boxes respectively. The signal processing electronics and data acquisition system are located remotely in a counting house outside of the blockhouse. This allows easy access for maintenance purposes, without the need to remove the detectors from the vacuum tank. The design will be described in detail. A position resolution of 8mm FWHM or less has been measured along the length of the tubes. The initial measurements taken from a standard sample indicate that whilst the detector arrays themselves only represent a moderate improvement in overall detection efficiency (~ 20%), compared to the previous detector, the count rate capability is increased by a factor of 100. A significant advantage of the new array is the ability to change a single tube in situ

  19. Neutron xyz - polarization analysis at a time-of-flight instrument

    SciTech Connect

    Ehlers, Georg; Stewart, John Ross; Andersen, Ken

    2015-01-01

    When implementing a dedicated polarization analysis setup at a neutron time-of-flight instrument with a large area detector, one faces enormous challenges. Nevertheless, significant progress has been made towards this goal over the last few years. This paper addresses systematic limitations of the traditional method that is used to make these measurements, and a possible strategy to overcome these limitations. This will be important, for diffraction as well as inelastic experiments, where the scattering occurs mostly out-of-plane.

  20. Determination of Cd and Cr in an ABS candidate reference material by instrumental neutron activation analysis.

    PubMed

    Park, Kwangwon; Kang, Namgoo; Cho, Kyunghaeng; Lee, Jounghae

    2008-12-01

    In order to practically better cope with technical barriers to trade (TBT) of a great number of resin goods, our research presents first-ever results for the determination of Cd and Cr in acrylonitrile butadiene styrene (ABS) candidate reference material using instrumental neutron activation analysis (INAA) recently recognized as a candidate primary ratio method with a particular attention to the estimation of involved measurement uncertainties.

  1. Instrumental neutron activation analysis of soil and sediment samples from Siwa Oasis, Egypt

    NASA Astrophysics Data System (ADS)

    Badawy, Wael M.; Ali, Khaled; El-Samman, Hussein M.; Frontasyeva, Marina V.; Gundorina, Svetlana F.; Duliu, Octavian G.

    2015-07-01

    Instrumental neutron activation analysis was used to study geochemical peculiarities of the Siwa Oasis in the Western Egyptian Desert. A total of 34 elements were determined in soil and sediment samples (Na, Mg, Al, Cl, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Sb, I, Cs, Ba, La, Ce, Nd, Eu, Tb, Dy, Tm, Yb, Hf, Ta, Th, and U). For data interpretation Cluster analysis was applied. Comparison with the available literature data was carried out.

  2. Salvinia auriculata: aquatic bioindicator studied by instrumental neutron activation analysis (INAA).

    PubMed

    Soares, Daniel Crístian Ferreira; de Oliveira, Ester Figueiredo; Silva, Grácia Divina de Fátima; Duarte, Lucienir Pains; Pott, Vali Joana; Vieira Filho, Sidney Augusto

    2008-05-01

    Through instrumental neutron activation analysis (INAA) the elemental chemical composition of Salvinia auriculata and Ouro Preto city public water was determined. Elements Ce, Th, Cr, Hf, Sb, Sc, Rb, Fe, Zn, Co, Au, La and Br were quantified. High chromium concentration was determined in this plant. But, chromium was determined only in low concentrations in the water. The results indicate the great capacity of this plant to absorb and accumulate inorganic elements.

  3. Fission converter and metal-oxide-semiconductor field effect transistor study of thermal neutron flux distribution in an epithermal neutron therapy beam.

    PubMed

    Kaplan, G I; Rosenfeld, A B; Allen, B J; Coderre, J A; Liu, H B

    1999-09-01

    The depth distribution of the thermal neutron flux is a major factor in boron neutron capture therapy (BNCT) in determining the efficiency of cell sterilization. In this paper the fission detector method is developed and applied to measure the in-phantom thermal neutron flux depth distribution. Advantages of the fission detector include small size, direct measurement of thermal neutron flux in a mixed radiation field of BNCT beam, self-calibration, and the possibility of on-line measurement. The measurements were performed at epithermal a BNCT facility. The experimental results were compared with the thermal neutron flux calculated by the Monte Carlo method and found to be in good agreement.

  4. Numerical Simulation of the MSL Dynamic Albedo of Neutrons (DAN) Instrument

    NASA Astrophysics Data System (ADS)

    Jun, I.; Mitrofanov, I.; Litvak, M.; Varenikov, A.

    2012-12-01

    The DAN instrument on the Mars Science Laboratory (MSL) has been tasked with detecting enhanced level of hydrogen content in the Martian subsurface. DAN accomplishes this goal by irradiating pulses of 14 MeV neutrons to the subsurface below the rover and by measuring the die-away time profiles of epi-thermal and thermal neutrons from the subsurface. Increased levels of thermal neutron are highly indicative of the presence of hydrogen (and thus water) in the soil. However, there are many factors that influence the thermalization process as well. To better understand the significance of these factors, we used the Monte Carlo N-Particle Extended (MCNPX) code to investigate numerous difference cases simulating conditions on the Martian surface that may affect the characteristics of die away curves. The results provide an insight into the varying impacts of factors such as water content in the soil, soil depth, soil density, temperature, soil elemental composition, and rover internal structure on the level of thermal neutrons, and ultimately better equip us to interpret real data from MSL. We will present some of the numerical simulation results performed on these factors, especially the effect of the mass distribution within the rover on the time profiles of thermal and epi-thermal neutron die-away curves. We also plan to show initial DAN measurement data obtained from a few months' of operation on the mars surface at the time of the conference.

  5. Advances in Neutron Spectroscopy and High Magnetic Field Instrumentation for studies of Correlated Electron Systems

    SciTech Connect

    Granroth, Garrett E

    2011-01-01

    Neutron Spectroscopy has provided critical information on the magnetism in correlated electron systems. Specifically quantum magnets, superconductors, and multi-ferroics are areas of productive research. A discussion of recent measurements on the SEQUOIA spectrometer will provide examples of how novel instrumentation concepts are used on the latest generation of spectrometers to extend our knowledge in such systems. The now ubiquitous function of sample rotation allows for full mapping of volumes of $Q$ and $\\omega$ space. An instrument focused on low angles could extend these maps to cover more of the first Brillioun zone. Innovative chopper cascades allow two unique modes of operation. Multiplexed measurements allow the simultaneous measurement of high and low energy features in an excitation spectrum. Alternatively by limiting the neutron bandwidth incident on the Fermi Chopper, background from subsequent time frames is removed, enabling the observation of weak, large energy transfer features. Finally the implementation of event-based detection for neutron experiments is time correlated experiments. Diffraction studies of the high field spin states in MnWO$_4$ using magnetic fields up to 30 T, provided by a pulsed magnet, illustrate this method. Expanding the high field studies to spectroscopy will require a novel instrument, focused around a world class DC magnet, like Zeemans proposed for the SNS.

  6. MCNP optimization of filtered neutron beams for calibration of the SIMPLE detector

    NASA Astrophysics Data System (ADS)

    Oliveira, C.; Giuliani, F.; Girard, T. A.; Marques, J. G.; Salgado, J.; Collar, J. I.; Morlat, T.; Limagne, D.; Waysand, G.

    2004-01-01

    We report an MCNP study of filtered monochromatic neutron beams of energies 25, 54 and 149 keV for response studies of a superheated droplet detector for the SIMPLE experiment. The results identify the importance of the detector temperature stabilizing water bath and the aqueous gel of the detector on the beam quality, in general agreement with recent measurements made on the thermal port of the Portuguese research reactor.

  7. 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.

  8. Performance predictions for a laser-intensified thermal beam for use in high-resolution focused-ion-beam instruments

    NASA Astrophysics Data System (ADS)

    Wouters, S. H. W.; ten Haaf, G.; Notermans, R. P. M. J. W.; Debernardi, N.; Mutsaers, P. H. A.; Luiten, O. J.; Vredenbregt, E. J. D.

    2014-12-01

    Photoionization of a laser-cooled and compressed atomic beam from a high-flux thermal source can be used to create a high-brightness ion beam for use in focused-ion-beam instruments. Here we show using calculations and Doppler cooling simulations that an atomic rubidium beam with an equivalent brightness of 2.1 ×107 A /(m 2 sr eV ) can be created using a compact 5 cm long two-dimensional magneto-optical compressor. If this can be conserved during the photoionization process, this leads to an ion beam brightness an order of magnitude higher than produced by a liquid metal ion source. The source is also capable of producing a flux of 6.2 ×109 s -1 that results in a substantial beam current of 1 nA once fully ionized.

  9. 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/.

  10. Off-axis neutron study from a uniform scanning proton beam using Monte Carlo code FLUKA

    NASA Astrophysics Data System (ADS)

    Islam, Mohammad Rafiqul

    The production of secondary neutrons is an undesirable byproduct of proton therapy. It is important to quantify the contribution from secondary neutrons to patient dose received outside the treatment volume. The purpose of this study is to investigate the off-axis dose equivalent from secondary neutrons using the Monte Carlo radiation transport code FLUKA. The study is done using a simplified version of the beam delivery system used at ProCure Proton Therapy Center, Oklahoma City, OK. In this study, a particular set of treatment parameters were set to study the dose equivalent outside the treatment volume inside a phantom and in air at various depths and angles with respect to the primary beam axis. Three different proton beams with maximum energies of 78 MeV, 162 MeV and 226 MeV and 4 cm modulation width, a 5 cm diameter brass aperture, and a small snout located 38 cm from isocenter were used for the study. The FLUKA calculated secondary neutron dose equivalent to absorbed proton dose, Hn/Dp, decreased with distance from beam isocenter. The Hn/Dp ranged from 0.11 +/- 0.01 mSv/Gy for a 78 MeV proton beam to 111.01 +/- 1.99 mSv/Gy for a 226 MeV proton beam. Overall, Hn/D p was observed to be higher in air than in the phantom, indicating the predominance of external neutrons produced in the nozzle rather than inside the body.

  11. Neutron contamination of Varian Clinac iX 10 MV photon beam using Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Yani, S.; Tursinah, R.; Rhani, M. F.; Soh, R. C. X.; Haryanto, F.; Arif, I.

    2016-03-01

    High energy medical accelerators are commonly used in radiotherapy to increase the effectiveness of treatments. As we know neutrons can be emitted from a medical accelerator if there is an incident of X-ray that hits any of its materials. This issue becomes a point of view of many researchers. The neutron contamination has caused many problems such as image resolution and radiation protection for patients and radio oncologists. This study concerns the simulation of neutron contamination emitted from Varian Clinac iX 10 MV using Monte Carlo code system. As neutron production process is very complex, Monte Carlo simulation with MCNPX code system was carried out to study this contamination. The design of this medical accelerator was modelled based on the actual materials and geometry. The maximum energy of photons and neutron in the scoring plane was 10.5 and 2.239 MeV, respectively. The number and energy of the particles produced depend on the depth and distance from beam axis. From these results, it is pointed out that the neutron produced by linac 10 MV photon beam in a typical treatment is not negligible.

  12. Feasibility of the utilization of BNCT in the fast neutron therapy beam at Fermilab

    SciTech Connect

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

    2000-06-23

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

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

    DOE R&D Accomplishments Database

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

    2000-06-01

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

  14. Differential Die-Away Instrument: Report on Benchmark Measurements and Comparison with Simulation for the Effects of Neutron Poisons

    SciTech Connect

    Goodsell, Alison Victoria; Swinhoe, Martyn Thomas; Henzl, Vladimir; Rael, Carlos D.; Desimone, David J.

    2015-03-30

    In this report, new experimental data and MCNPX simulation results of the differential die-away (DDA) instrument response to the presence of neutron absorbers are evaluated. In our previous fresh nuclear fuel experiments and simulations, no neutron absorbers or poisons were included in the fuel definition. These new results showcase the capability of the DDA instrument to acquire data from a system that better mimics spent nuclear fuel.

  15. 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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  19. Neutron Measurement Instrumentation Development at KIT for the European ITER TBM

    SciTech Connect

    Klix, A.; Fischer, U.; Raj, P.; Reimann, Th.; Szalkai, D.; Tian, K.; Angelone, M.; Gehre, D.; Lyoussi, A.

    2015-07-01

    Fusion power reactors will rely on the internal production of the fuel tritium from lithium in the tritium breeding blanket. Test Blanket Modules (TBM) will be installed in ITER with the aim to investigate the nuclear performance of different breeding blanket designs. Currently there is no fully qualified nuclear instrumentation available for the measurement of neutron fluxes and tritium production rates which would be able to withstand the harsh environment conditions in the TBM such as high temperature (>400 deg. C) and, depending on the operation scenario, intense radiation levels. As partner of the European Consortium on Nuclear Data and Measurement Techniques in the framework of several F4E specific grants and contracts, KIT and ENEA have jointly studied the possibility to develop and test detectors suitable to operate in ITER-TBMs. Here we present an overview of ongoing work on three types of neutron flux monitors under development for the TBMs with focus on the KIT activities. A neutron activation system (NAS) with pneumatic sample transport could provide absolute neutron flux measurements in selected positions. A test system for investigating activation materials with short half-lives was constructed at the DT neutron generator laboratory of Technical University of Dresden to investigate the neutronics aspects. Several irradiations have been performed with focus on the simultaneous measurement of the extracted activated probes. An engineering assessment of a TBM NAS in the conceptual design phase has been done which considered issues of design requirements and integration. Last but not least, a mechanical test bench is under construction at KIT which will address issues of driving the activation probes, solutions for loading the system etc. experimentally. Self-powered neutron detectors (SPND) are widely applied in fission reactor monitoring, and the commercially available SPNDs are sensitive to thermal neutrons. We are investigating novel materials for

  20. Multipurpose epithermal neutron beam on new research station at MARIA research reactor in Swierk-Poland

    SciTech Connect

    Gryzinski, M.A.; Maciak, M.

    2015-07-01

    MARIA reactor is an open-pool research reactor what gives the chance to install uranium fission converter on the periphery of the core. It could be installed far enough not to induce reactivity of the core but close enough to produce high flux of fast neutrons. Special design of the converter is now under construction. It is planned to set the research stand based on such uranium converter in the near future: in 2015 MARIA reactor infrastructure should be ready (preparation started in 2013), in 2016 the neutron beam starts and in 2017 opening the stand for material and biological research or for medical training concerning BNCT. Unused for many years, horizontal channel number H2 at MARIA research rector in Poland, is going to be prepared as a part of unique stand. The characteristics of the neutron beam will be significant advantage of the facility. High flux of neutrons at the level of 2x10{sup 9} cm{sup -2}s{sup -1} will be obtainable by uranium neutron converter located 90 cm far from the reactor core fuel elements (still inside reactor core basket between so called core reflectors). Due to reaction of core neutrons with converter U{sub 3}Si{sub 2} material it will produce high flux of fast neutrons. After conversion neutrons will be collimated and moderated in the channel by special set of filters and moderators. At the end of H2 channel i.e. at the entrance to the research room neutron energy will be in the epithermal energy range with neutron intensity at least at the level required for BNCT (2x10{sup 9} cm{sup -2}s{sup -1}). For other purposes density of the neutron flux could be smaller. The possibility to change type and amount of installed filters/moderators which enables getting different properties of the beam (neutron energy spectrum, neutron-gamma ratio and beam profile and shape) is taken into account. H2 channel is located in separate room which is adjacent to two other empty rooms under the preparation for research laboratories (200 m2). It is

  1. OER and RBE of high energy neutron beams for growth inhibition in Vicia faba.

    PubMed

    Van Dam, J; Billiet, G; Zoetelief, J; Broerse, J J; Wambersie, A

    1983-01-01

    The radiobiologic characteristics of 15 MeV neutrons produced by the d + T reaction at the TNO of Rijswijk and of neutrons produced by the d(50) + Be and p(75) + Be reactions at the cyclotron Cyclone of Louvain-la- Neuve were compared. Growth inhibition in Vicia faba bean roots was used as biologic system. An OER value of 1.5 +/- 0.1 ws obtained for the neutron beams compared. The RBE of 15 MeV, d(50) + Be and p(75) + Be neutrons was found equal to 3.4 +/- 0.2, 3.2 +/- 0.2 and 2.9 +/- 0.3, respectively, relative to gamma rays, for a total (n + gamma) absorbed dose of 0.6 Gy.

  2. 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.

  3. Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

    NASA Astrophysics Data System (ADS)

    Rasmussen, N. G.; Simeoni, G. G.; Lefmann, K.

    2016-04-01

    A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (adjustable supermirror curvature) and the compact size (only 0.5 m long). We have simulated the neutron transport across the entire guide system. We present a detailed computer characterization of the existing device, along with the study of the factors mostly influencing the future improvement. We have optimized the simulated prototype as a function of the neutron wavelength, accounting also for all relevant features of a real instrument like the non-reflecting side edges. The results confirm the "chromatic" displacement of the focal point (flux density maximum) at fixed supermirror curvature, and the ability of a variable curvature to keep the focal point at the sample position. Our simulations are in excellent agreement with theoretical predictions and the experimentally measured beam profile. With respect to the possibility of a further upgrade, we find that supermirror coatings with m-values higher than 3.5 would have only marginal influence on the optimal behaviour, whereas comparable spectrometers could take advantage of longer focusing segments, with particular impact for the thermal region of the neutron spectrum.

  4. Proceedings of the Oak Ridge National Laboratory/Brookhaven National Laboratory workshop on neutron scattering instrumentation at high-flux reactors

    SciTech Connect

    McBee, M.R.; Axe, J.D.; Hayter, J.B.

    1990-07-01

    For the first three decades following World War II, the US, which pioneered the field of neutron scattering research, enjoyed uncontested leadership in the field. By the mid-1970's, other countries, most notably through the West European consortium at Institut Laue-Langevin (ILL) in Grenoble, France, had begun funding neutron scattering on a scale unmatched in this country. By the early 1980's, observers charged with defining US scientific priorities began to stress the need for upgrading and expansion of US research reactor facilities. The conceptual design of the ANS facility is now well under way, and line-item funding for more advanced design is being sought for FY 1992. This should lead to a construction request in FY 1994 and start-up in FY 1999, assuming an optimal funding profile. While it may be too early to finalize designs for instruments whose construction is nearly a decade removed, it is imperative that we begin to develop the necessary concepts to ensure state-of-the-art instrumentation for the ANS. It is in this context that this Instrumentation Workshop was planned. The workshop touched upon many ideas that must be considered for the ANS, and as anticipated, several of the discussions and findings were relevant to the planning of the HFBR Upgrade. In addition, this report recognizes numerous opportunities for further breakthroughs on neutron instrumentation in areas such as improved detection schemes (including better tailored scintillation materials and image plates, and increased speed in both detection and data handling), in-beam monitors, transmission white beam polarizers, multilayers and supermirrors, and more. Each individual report has been cataloged separately.

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

    PubMed

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

    2015-12-01

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

  6. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1996-06-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described.

  7. LANSCE beam instrumentation and the LANSCE refurbishment project

    SciTech Connect

    Mccrady, Rodney C; Blind, Barbara; Gilpatrick, John D; Pillai, Chandra; Power, John F; Rybarcyk, Lawrence J; Sedillo, James D; Gruchalla, Michael E

    2010-01-01

    The heart of the LANSCE accelerator complex consists of Cockroft-Walton-type injectors, a drift-tube linac (DTL) and a side-coupled linac (CCL). These systems are approaching 40 years of age and a project to re-establish high-power capability and to extend the lifetime is underway. Many of the present beam diagnostic systems are difficult to maintain, and the original beam position monitors don't provide any data at all. These deficiencies hamper beam tuning and trouble-shooting efforts. One thrust of the refurbishment project is to restore reliable operation of the diagnostic systems. This paper describes the present diagnostics systems and their limitations and the envisaged next-generation systems. The emphasis will be on the uses and requirements for the systems rather than the solutions and engineering aspects of the refurbishment.

  8. Instrumentation for diagnostics and control of laser-accelerated proton (ion) beams.

    PubMed

    Bolton, P R; Borghesi, M; Brenner, C; Carroll, D C; De Martinis, C; Fiorini, Francesca; Flacco, A; Floquet, V; Fuchs, J; Gallegos, P; Giove, D; Green, J S; Green, S; Jones, B; Kirby, D; McKenna, P; Neely, D; Nuesslin, F; Prasad, R; Reinhardt, S; Roth, M; Schramm, U; Scott, G G; Ter-Avetisyan, S; Tolley, M; Turchetti, G; Wilkens, J J

    2014-05-01

    Suitable instrumentation for laser-accelerated proton (ion) beams is critical for development of integrated, laser-driven ion accelerator systems. Instrumentation aimed at beam diagnostics and control must be applied to the driving laser pulse, the laser-plasma that forms at the target and the emergent proton (ion) bunch in a correlated way to develop these novel accelerators. This report is a brief overview of established diagnostic techniques and new developments based on material presented at the first workshop on 'Instrumentation for Diagnostics and Control of Laser-accelerated Proton (Ion) Beams' in Abingdon, UK. It includes radiochromic film (RCF), image plates (IP), micro-channel plates (MCP), Thomson spectrometers, prompt inline scintillators, time and space-resolved interferometry (TASRI) and nuclear activation schemes. Repetition-rated instrumentation requirements for target metrology are also addressed.

  9. Small-angle neutron scattering instrument of Institute for Solid State Physics, the Univeristy of Tokyo (SANS-U) and its application to biology

    SciTech Connect

    Ito, Yuji; Imai, Masayuki; Takahashi, Shiro

    1994-12-31

    A small-angle neutron spectrometer (SANS-U) suitable for the study of mesoscopic structure in the field of polymer chemistry and biology, has been constructed at the guide hall of JRR-3M reactor at the Japan Atomic Energy Research Institute. The instrument is 32m long and utilizes a mechanical velocity selector and pinhole collimation to provide a continuous beam with variable wavelength in the range from 5 to 10{Angstrom}. The neutron detector is a 65 x 65cm{sup 2} 2D position sensitive proportional counter. The practical Q range of SANS-U is 0.0008 to 0.45{Angstrom}{sup -1}. The design, characteristics and performance of SANS-U are described with some biological studies using SANS-U.

  10. 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.

  11. An optimized neutron-beam shaping assembly for accelerator-based BNCT.

    PubMed

    Burlon, A A; Kreiner, A J; Valda, A A; Minsky, D M

    2004-11-01

    Different materials and proton beam energies have been studied in order to search for an optimized neutron production target and beam shaping assembly for accelerator-based BNCT. The solution proposed in this work consists of successive stacks of Al, polytetrafluoroethylene, commercially known as Teflon, and LiF as moderator and neutron absorber, and Pb as reflector. This assembly is easy to build and its cost is relatively low. An exhaustive Monte Carlo simulation study has been performed evaluating the doses delivered to a Snyder model head phantom by a neutron production Li-metal target based on the (7)Li(p,n)(7)Be reaction for proton bombarding energies of 1.92, 2.0, 2.3 and 2.5 MeV. Three moderator thicknesses have been studied and the figures of merit show the advantage of irradiating with near-resonance-energy protons (2.3 MeV) because of the relatively high neutron yield at this energy, which at the same time keeps the fast neutron healthy tissue dose limited and leads to the lowest treatment times. A moderator of 34 cm length has shown the best performance among the studied cases.

  12. Plasma focus neutron anisotropy measurements and influence of a deuteron beam obstacle

    NASA Astrophysics Data System (ADS)

    Talebitaher, A.; Springham, S. V.; Rawat, R. S.; Lee, P.

    2017-03-01

    The deuterium-deuterium (DD) fusion neutron yield and anisotropy were measured on a shot-to-shot basis for the NX2 plasma focus (PF) device using two beryllium fast-neutron activation detectors at 0° and 90° to the PF axis. Measurements were performed for deuterium gas pressures in the range 6-16 mbar, and positive correlations between neutron yield and anisotropy were observed at all pressures. Subsequently, at one deuterium gas pressure (13 mbar), the contribution to the fusion yield produced by the forwardly-directed D+ ion beam, emitted from the plasma pinch, was investigated by using a circular Pyrex plate to obstruct the beam and suppress its fusion contribution. Neutron measurements were performed with the obstacle positioned at two distances from the anode tip, and also without the obstacle. It was found that 80% of the neutron yield originates in the plasma pinch column and just above that. In addition, proton pinhole imaging was performed from the 0° and 90° directions to the pinch. The obtained proton images are consistent with the conclusion that DD fusion is concentrated ( 80%) in the pinch column region.

  13. Inverse-kinematics one-neutron pickup with fast rare-isotope beams

    SciTech Connect

    Gade, A.; Baugher, T.; Brown, B. A.; Glasmacher, T.; McDaniel, S.; Ratkiewicz, A.; Stroberg, S. R.; Tostevin, J. A.; Bazin, D.; Campbell, C. M.; Grinyer, G. F.; Weisshaar, D.; Winkler, R.; Meierbachtol, K.; Walsh, K. A.

    2011-05-15

    Measurements and reaction model calculations are reported for single-neutron pickup reactions onto a fast {sup 22}Mg secondary beam at 84 MeV per nucleon. Measurements made on both carbon and beryllium targets, having very different structures, were used to investigate the likely nature of the pickup reaction mechanism. The measurements involve thick reaction targets and {gamma}-ray spectroscopy of the projectile-like reaction residue for final-state resolution, which permit experiments with low incident beam rates compared to traditional low-energy transfer reactions. From measured longitudinal momentum distributions we show that the {sup 12}C({sup 22}Mg,{sup 23}Mg+{gamma})X reaction largely proceeds as a direct two-body reaction, with the neutron transfer producing bound {sup 11}C target residues. The corresponding reaction on the {sup 9}Be target seems to largely leave the {sup 8}Be residual nucleus unbound at excitation energies high in the continuum. We discuss the possible use of such fast-beam one-neutron pickup reactions to track single-particle strength in exotic nuclei and also their expected sensitivity to neutron high-l (intruder) states, which are often direct indicators of shell evolution and the disappearance of magic numbers in the exotic regime.

  14. Inverse-kinematics one-neutron pickup with fast rare-isotope beams

    NASA Astrophysics Data System (ADS)

    Gade, A.; Tostevin, J. A.; Baugher, T.; Bazin, D.; Brown, B. A.; Campbell, C. M.; Glasmacher, T.; Grinyer, G. F.; McDaniel, S.; Meierbachtol, K.; Ratkiewicz, A.; Stroberg, S. R.; Walsh, K. A.; Weisshaar, D.; Winkler, R.

    2011-05-01

    Measurements and reaction model calculations are reported for single-neutron pickup reactions onto a fast Mg22 secondary beam at 84 MeV per nucleon. Measurements made on both carbon and beryllium targets, having very different structures, were used to investigate the likely nature of the pickup reaction mechanism. The measurements involve thick reaction targets and γ-ray spectroscopy of the projectile-like reaction residue for final-state resolution, which permit experiments with low incident beam rates compared to traditional low-energy transfer reactions. From measured longitudinal momentum distributions we show that the 12C(22Mg,23Mg+γ)X reaction largely proceeds as a direct two-body reaction, with the neutron transfer producing bound C11 target residues. The corresponding reaction on the Be9 target seems to largely leave the Be8 residual nucleus unbound at excitation energies high in the continuum. We discuss the possible use of such fast-beam one-neutron pickup reactions to track single-particle strength in exotic nuclei and also their expected sensitivity to neutron high-ℓ (intruder) states, which are often direct indicators of shell evolution and the disappearance of magic numbers in the exotic regime.

  15. The Macromolecular Neutron Diffractometer MaNDi at the Spallation Neutron Source

    DOE PAGES

    Coates, Leighton; Cuneo, Matthew J.; Frost, Matthew J.; ...

    2015-07-18

    The Macromolecular Neutron Diffractometer (MaNDi) is located on beamline 11B of the Spallation Neutron Source at Oak Ridge National Laboratory. Moreover, the instrument is a neutron time-of-flight wavelength-resolved Laue diffractometer optimized to collect diffraction data from single crystals. Finally, the instrument has been designed to provide flexibility in several instrumental parameters, such as beam divergence and wavelength bandwidth, to allow data collection from a range of macromolecular systems.

  16. The Macromolecular Neutron Diffractometer MaNDi at the Spallation Neutron Source

    SciTech Connect

    Coates, Leighton; Cuneo, Matthew J.; Frost, Matthew J.; He, Junhong; Weiss, Kevin L.; McFeeters, Hana; Tomanicek, Stephen J.; Vandavasi, Venu Gopal; Langan, Paul; Iverson, Erik B.

    2015-07-18

    The Macromolecular Neutron Diffractometer (MaNDi) is located on beamline 11B of the Spallation Neutron Source at Oak Ridge National Laboratory. Moreover, the instrument is a neutron time-of-flight wavelength-resolved Laue diffractometer optimized to collect diffraction data from single crystals. Finally, the instrument has been designed to provide flexibility in several instrumental parameters, such as beam divergence and wavelength bandwidth, to allow data collection from a range of macromolecular systems.

  17. A novel methodology to determine the divergence of a neutron beam

    NASA Astrophysics Data System (ADS)

    Souza, E. S.; Almeida, G. L.; Lopes, R. T.

    2016-12-01

    This work posits a novel approach to characterize the divergence of a neutron beam emerging from a reactor port. Unlike the usual inverse of the L/D ratio, the term divergence as employed here refers to the deviation from an ideal parallel beam emitted from a surface source. Within this concept, an ideal point source in spite of its conical beam would not exhibit any divergence. Hence, the beam divergence of a surface source is more adequately characterized adopting the notion of Rocking Curve - RC, a term borrowed from the X-ray diffraction field. After this idea, every point of the surface source emits neutrons in all directions but with different intensities following a bell-shaped profile. Once the RC semi-width is determined, it is possible to assess its effect upon the quality of an acquired neutron radiograph, since it incorporates degrading agents such as geometrical unsharpness, neutron scattering, noise and statistical dispersion. In this work an inverse procedure is applied, i.e., to use an actual neutron radiograph to find the RC semi-width. To accomplish this task, synthetic images - generated with defined RC semi-widths and object-detector gaps - are compared with experimental ones acquired with the same gaps in order to find the most resemblance between them. The angular semi-width of the best synthetic image is assigned to that of the experimental one, defining thus the aimed beam divergence, which has been compared with a different method with a fair agreement. An equivalent procedure embedded in the algorithm has been employed to evaluate the L/D using the same radiographic images. The outcome fairly agrees with the value inferred from the neutron flux ratio at different locations. Both approaches RC semi-width and L/D ratio yielded consistent results with other utterly different methods. Yet, the rocking curve approach forecasts more precisely the neutron pattern hitting the detector and does not need a precisely machined test-object as required

  18. Shielding for neutron scattered dose to the fetus in patients treated with 18 MV x-ray beams.

    PubMed

    Roy, S C; Sandison, G A

    2000-08-01

    Neutrons are associated with therapeutic high energy x-ray beams as a contaminant that contributes significant unwanted dose to the patient. Measurement of both photon and neutron scattered dose at the position of a fetus from chest irradiation by a large field 18 MV x-ray beam was performed using an ionization chamber and superheated drop detector, respectively. Shielding construction to reduce this scattered dose was investigated using both lead sheet and borated polyethylene slabs. A 7.35 cm lead shield reduced the scattered photon dose by 50% and the scattered neutron dose by 40%. Adding 10 cm of 5% borated polyethylene to this lead shield reduced the scattered neutron dose by a factor of 7.5 from the unshielded value. When the 5% borated polyethylene was replaced by the same thickness of 30% borated polyethylene there was no significant change in the reduction of neutron scatter dose. The most efficient shield studied reduced the neutron scatter dose by a factor of 10. The results indicate that most of the scattered neutrons present at the position of the fetus produced by an 18 MV x-ray beam are of low energy and in the thermal to 0.57 MeV range since lead is almost transparent to neutrons with energies lower than 0.57 MeV. This article constitutes the first report of an effective shield to reduce neutron dose at the fetus when treating a pregnant woman with a high energy x-ray beam.

  19. Evaluation of homogeneity of a certified reference material by instrumental neutron activation analysis

    SciTech Connect

    Kratochvil, B.; Duke, M.J.M.; Ng, D.

    1986-01-01

    The homogeneity of the marine reference material TORT-1, a spray-dried and acetone-extracted hepatopancreatic material from the lobster, was tested for 26 elements by instrumental neutron activation analysis (INAA). Through a one-way analysis of variance based on six analyses on each of six bottles of TORT-1, it was concluded that the between-bottle heterogeneity is no greater than the within-bottle heterogeneity. The analytical results for those elements for which values were provided by NRC agree with the NRC values within 95% confidence limits. 8 references, 6 tables.

  20. An irradiation facility for Boron Neutron Capture Therapy application based on a radio frequency driven D-T neutron source and a new beam shaping assembly

    NASA Astrophysics Data System (ADS)

    Cerullo, Nicola; Esposito, Juan; Leung, Ka Ngo; Custodero, Salvatore

    2002-10-01

    A line of the Boron Neutron Capture Therapy (BNCT) research program aimed at the treatment of brain tumors, carried on at the Nuclear Departments of Pisa and Genova Universities (DIMNP and DITEC), is being focused on a new, 3H(d,n)4He (D-T), accelerator-based neutron source concept, developed at Lawrence Berkeley National Laboratory (LBNL). Simple and compact accelerator designs, using mixed D+ T+ ion beam with relatively low energy, ˜100 keV, have been developed which, in turn, can generate high neutron yields. New approaches have thus been started to design an epithermal neutron irradiation facility able to selectively slow the 14.1 MeV D-T neutrons down to the epithermal (1 eV-10 KeV) energy range. New neutron spectrum shifter and filtering materials, as well as different facility layout approaches have been tested. Possible beam shaping assembly models have also been designed. The research demonstrates that a D-T neutron source could be successfully implemented to provide a ˜1×109 n/cm2 s epithermal neutron flux, in spite of its hard spectrum, although a generator device, able to yield ˜1014 n/s is, at present, not yet available. The latest Monte Carlo simulation of an accelerator-based facility, which relies on a single or multiple rf driven DT fusion neutron generator, is presented.

  1. High energy neutron response characteristics of a passive survey instrument for the determination of cosmic radiation fields in aircraft.

    PubMed

    Bartlett, D T; Tanner, R J; Hager, L G

    2002-01-01

    A passive survey instrument has been developed for the determination of cosmic radiation fields in aircraft. The instrument contains 30 TLDs and 36 PADC etched track detectors in order to obtain the required precision and an isotropic response. Two active electronic personal dosemeters are included to record the time profile of the field intensity. The instrument is robust and reliable, and is particularly useful to verify values of route doses based on calculations. The energy of the neutron component of the field to be determined extends to over 500 MeV, but with the majority of the dose equivalent below 200 MeV. The results are reported of measurements at Uppsala University and Physikalisch-Technische Bundesanstalt of the response characteristics of the instrument to quasi-monoenergetic neutrons in the energy range 60 to 180 MeV and for monoenergetic neutrons of energy from 70 keV to 14.7 MeV.

  2. Planck 2015 results. IV. Low Frequency Instrument beams and window functions

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Chamballu, A.; Christensen, P. R.; Colombi, S.; Colombo, L. P. L.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kiiveri, K.; Kisner, T. S.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leahy, J. P.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; Lindholm, V.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Novikov, D.; Novikov, I.; Paci, F.; Pagano, L.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Pierpaoli, E.; Pietrobon, D.; Pointecouteau, E.; Polenta, G.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renzi, A.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Stolyarov, V.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vassallo, T.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Watson, R.; Wehus, I. K.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-09-01

    This paper presents the characterization of the in-flight beams, the beam window functions, and the associated uncertainties for the Planck Low Frequency Instrument (LFI). The structure of the paper is similar to that presented in the 2013 Planck release; the main differences concern the beam normalization and the delivery of the window functions to be used for polarization analysis. The in-flight assessment of the LFI main beams relies on measurements performed during observations of Jupiter. By stacking data from seven Jupiter transits, the main beam profiles are measured down to -25 dB at 30 and 44 GHz, and down to -30 dB at 70 GHz. It has been confirmed that the agreement between the simulated beams and the measured beams is better than 1% at each LFI frequency band (within the 20 dB contour from the peak, the rms values are 0.1% at 30 and 70 GHz; 0.2% at 44 GHz). Simulated polarized beams are used for the computation of the effective beam window functions. The error budget for the window functions is estimated from both main beam and sidelobe contributions, and accounts for the radiometer band shapes. The total uncertainties in the effective beam window functions are 0.7% and 1% at 30 and 44 GHz, respectively (at ℓ ≈ 600); and 0.5% at 70 GHz (at ℓ ≈ 1000).

  3. Thermal neutron self-shielding correction factors for large sample instrumental neutron activation analysis using the MCNP code

    NASA Astrophysics Data System (ADS)

    Tzika, F.; Stamatelatos, I. E.

    2004-01-01

    Thermal neutron self-shielding within large samples was studied using the Monte Carlo neutron transport code MCNP. The code enabled a three-dimensional modeling of the actual source and geometry configuration including reactor core, graphite pile and sample. Neutron flux self-shielding correction factors derived for a set of materials of interest for large sample neutron activation analysis are presented and evaluated. Simulations were experimentally verified by measurements performed using activation foils. The results of this study can be applied in order to determine neutron self-shielding factors of unknown samples from the thermal neutron fluxes measured at the surface of the sample.

  4. Implementation of gamma-ray instrumentation for solid solar system bodies using neutron activation method

    NASA Astrophysics Data System (ADS)

    Litvak, M. L.; Golovin, D. V.; Jun, I.; Kozyrev, A. S.; Mitrofanov, I. G.; Sanin, A. B.; Shvetsov, V. N.; Timoshenko, G. N.; Zontikov, A.

    2016-06-01

    In this paper we present the results of ground tests performed with a flight model and with industry prototypes of passive and active gamma ray spectrometers with the objective of understanding their capability to distinguish the elemental composition of planetary bodies in the solar system. The gamma instrumentation, which was developed for future space missions was used in the measurements at a special ground test facility where a simulant of planetary material was fabricated with a martian-like composition. In this study, a special attention was paid to the gamma lines from activation reaction products generated by a pulsed neutron generator. The instrumentation was able to detect and identify gamma lines attributed to O, Na, Mg, Al, Si, K, Ca and Fe.

  5. A measurement of the fast-neutron sensitivity of a Geiger - Müller detector in the pulsed neutron beam from a superconducting cyclotron

    NASA Astrophysics Data System (ADS)

    Maughan, R. L.; Yudelev, M.; Kota, C.

    1996-08-01

    The value of a commercially available miniature energy compensated Geiger - Müller (GM) detector has been determined using the modified lead attenuation method of Hough. The measurements were made in a d(48.5) - Be neutron beam produced by the superconducting cyclotron based neutron therapy facility at Harper Hospital. The unique problems associated with making measurements in a 2 ms duration pulsed beam with a 20% duty cycle are discussed. The beam monitoring system, which allows the beam pulse shape at low beam intensities to be measured, is described. By gating the GM output with a discriminator pulse derived from the beam pulse shape, the gamma-ray count rates and dead-time corrections within the 2 ms pulse and between pulses can be measured separately. The value of determined for this GM detector is consistent with the values measured by other workers with identical and similar detectors in neutron beams with comparable, but not identical, neutron spectra.

  6. Physical characteristics of the M.D. Anderson Hospital clinical neutron beam.

    PubMed

    Horton, J L; Otte, V A; Schultheiss, T E; Stafford, P M; Sun, T; Zermeno, A

    1988-09-01

    The physical characteristics of the M.D. Anderson Hospital (MDAH) clinical neutron beam are presented. The central-axis percent depth-dose values are intermediate between a 4 and 6 MV X-ray beam. The build-up curves reach a depth of maximum dose at 1.2 cm and have surface dose values of approximately 30%. Teflon flattening filters are employed to flatten the beam at the depth of the 75% dose level. Two wedges are available for shaping the beam; they are made of Teflon and produce wedge angles of 31 degrees and 45 degrees as defined by the ICRU. Output factors ranged from 0.88 for a 4 x 4 cm field to 1.12 for a 20 x 20 cm field. Tungsten blocks reduced the dose received at Dmax to 25% of the unblocked value but only 52% of the unblocked value at a depth of 22.8 cm.

  7. Neutron lifetime measurement with pulsed beam at J-PARC:Incident Beam Flux

    NASA Astrophysics Data System (ADS)

    Sakakibara, Risa; Shimizu, Hirohiko M.; Kitaguchi, Masaaki; Hirota, Katsuya; Sugino, Tomoaki; Yamashita, Satoru; Katayama, Ryo; Yamada, Takahito; Higashi, Nao; Yokoyama, Harumichi; Sumino, Hirochika; Yoshioka, Tamaki; Otono, Hidetoshi; Tanaka, Genki; Sumi, Naoyuki; Iwashita, Yoshihisa; Kitahara, Ryunosuke; Oide, Hideyuki; Shima, Tatsushi; Ino, Takashi; Mishima, Kenji; Taketani, Kaoru; Seki, Yoshichika; NOP Collaboration

    2014-09-01

    The neutron lifetime is one of the important parameters in the estimation of the abundance of the light elements in the early universe through the Big Bang Nucleosynthesis (BBN). The accuracy of 0.1% is desired in the neutron lifetime to quantitatively discuss the BBN in combination with the observation of the anisotropy of the cosmic microwave. We have started a lifetime measurement with pulsed neutrons at J-PARC/BL05. To measure the lifetime, we detect the decay electrons from the bunched neutrons and the incident neutron flux in the TPC at the same time. By diluting a small amount of 3He gas into the TPC, the incident flux is estimated by counting protons via 3He(n,p)3H reactions. The accuracy of the selection of 3He(n,p)3H events and the influence of the contamination of nitrogen gas are the major systematic errors. In this paper, the estimation of the systematic error in the incident flux is reported.

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

    SciTech Connect

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

    2010-08-01

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

  9. LANSCE beam current limiter

    SciTech Connect

    Gallegos, F.R.

    1997-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the beam current limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beamline below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described. {copyright} {ital 1997 American Institute of Physics.}

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

    PubMed

    Yonezawa, C

    1999-01-01

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

  11. Measurement of neutron spectra generated by a 62 AMeV carbon-ion beam on a PMMA phantom using extended range Bonner sphere spectrometers

    NASA Astrophysics Data System (ADS)

    Bedogni, R.; Amgarou, K.; Domingo, C.; Russo, S.; Cirrone, G. A. P.; Pelliccioni, M.; Esposito, A.; Pola, A.; Introini, M. V.; Gentile, A.

    2012-07-01

    Neutrons constitute an important component of the radiation environment in hadron therapy accelerators. Their energy distribution may span from thermal up to hundred of MeV. The characterization of these fields in terms of dosimetric or spectrometric quantities is crucial for either the patient protection or the facility design aspects. To date, the Extended Range Bonner Sphere Spectrometer (ERBSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, a measurement campaign was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN-LNS (Laboratori Nazionali del Sud), where a 62 AMeV carbon ion is available. The beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. The ERBSSs of UAB (Universidad Autónoma de Barcelona-Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati) were used to measure the resulting neutron fields. The two ERBSSs use different detectors and sphere diameters, and have been independently calibrated. The FRUIT code was used to unfold the results.

  12. Overview of Beam Instrumentation and Diagnostics for the NSLS-II Project

    SciTech Connect

    Singh,O.

    2008-05-04

    A new, ultra-bright 3rd generation light source, the NSLS-II Project, is planned to be built at Brookhaven National Laboratory. The light source being developed will have unprecedently small beam horizontal emittance and will provide the radiation sources with a brightness of 3 x 10{sup 21} photons/sec/0.1%BW/mm{sup 2}/mrad{sup 2}. In this paper we present the detailed specifications and a comprehensive description of the planned beam instrumentation system and the first results of the ongoing instrumentation R&D activities on beyond state-of-the-art subsystems.

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

    SciTech Connect

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

    1989-02-01

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

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

    PubMed

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

    1989-02-01

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

  15. Monte-Carlo simulation of an ultra small-angle neutron scattering instrument based on Soller slits

    SciTech Connect

    Rieker, T.; Hubbard, P.

    1997-09-01

    Monte Carlo simulations are used to investigate an ultra small-angle neutron scattering instrument for use at a pulsed source based on a Soller slit collimator and analyzer. The simulations show that for a q{sub min} of {approximately}le-4 {angstrom}{sup -1} (15 {angstrom} neutrons) a few tenths of a percent of the incident flux is transmitted through both collimators at q=0.

  16. Concept for a time-of-flight Small Angle Neutron Scattering instrument at the European Spallation Source

    NASA Astrophysics Data System (ADS)

    Jaksch, S.; Martin-Rodriguez, D.; Ostermann, A.; Jestin, J.; Duarte Pinto, S.; Bouwman, W. G.; Uher, J.; Engels, R.; Frielinghaus, H.

    2014-10-01

    A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards μm and tens of μm, respectively. Two 1 m2 area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.

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

    SciTech Connect

    Van Hoy, Blake W

    2014-01-01

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

  18. Development of the Probing In-Situ with Neutron and Gamma Rays (PING) Instrument for Planetary Science Applications

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Burger, D.; Evans, L.; Floyd, S; Lim, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

    2011-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument is a promising planetary science application of the active neutron-gamma ray technology that has been used successfully in oil field well logging and mineral exploration on Earth for decades. Similar techniques can be very powerful for non-invasive in situ measurements of the subsurface elemental composition on other planets. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring instruments using this technology to the point where they can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets. PING combines a 14 MeV deuterium-tritium pulsed neutron generator with a gamma ray spectrometer and two neutron detectors to produce a landed instrument that can determine the elemental composition of a planet down to 30 - 50 cm below the planet's surface. The penetrating nature of.5 - 10 MeV gamma rays and 14 MeV neutrons allows such sub-surface composition measurements to be made without the need to drill into or otherwise disturb the planetary surface, thus greatly simplifying the lander design. We are currently testing a PING prototype at a unique outdoor neutron instrumentation test facility at NASA/GSFC that provides two large (1.8 m x 1.8 m x.9 m) granite and basalt test formations placed outdoors in an empty field. Since an independent trace elemental analysis has been performed on both the Columbia River basalt and Concord Gray granite materials, these samples present two known standards with which to compare PING's experimentally measured elemental composition results. We will present experimental results from PING measurements of both the granite and basalt test formations and show how and why the optimum PING instrument operating parameters differ for studying the two materials.

  19. Measurement of the neutron fields produced by a 62 MeV proton beam on a PMMA phantom using extended range Bonner sphere spectrometers

    NASA Astrophysics Data System (ADS)

    Amgarou, K.; Bedogni, R.; Domingo, C.; Esposito, A.; Gentile, A.; Carinci, G.; Russo, S.

    2011-10-01

    The experimental characterization of the neutron fields produced as parasitic effect in medical accelerators is assuming an increased importance for either the patient protection or the facility design aspects. Medical accelerators are diverse in terms of particle type (electrons or hadrons) and energy, but the radiation fields around them have in common (provided that a given threshold energy is reached) the presence of neutrons with energy span over several orders of magnitude. Due to the large variability of neutron energy, field or dosimetry measurements in these workplaces are very complex, and in general, cannot be performed with ready-to-use commercial instruments. In spite of its poor energy resolution, the Bonner Sphere Spectrometer (BSS) is the only instrument able to simultaneously determine all spectral components in such workplaces. The energy range of this instrument is limited to E<20 MeV if only polyethylene spheres are used, but can be extended to hundreds of MeV by including metal-loaded spheres (extended range BSS, indicated with ERBSS). With the aim of providing useful data to the scientific community involved in neutron measurements at hadron therapy facilities, an ERBSS experiment was carried out at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) of INFN—LNS (Laboratori Nazionali del Sud), where a proton beam routinely used for ophthalmic cancer treatments is available. The 62 MeV beam was directed towards a PMMA phantom, simulating the patient, and two neutron measurement points were established at 0° and 90° with respect to the beam-line. Here the ERBSS of UAB (Universidad Autónoma de Barcelona— Grup de Física de les Radiacions) and INFN (Istituto Nazionale di Fisica Nucleare—Laboratori Nazionali di Frascati) were exposed to characterize the "forward" and "sideward" proton-induced neutron fields. The use of two ERBSS characterized by different set of spheres, central detectors, and independently established and

  20. Final report: DOE Grant ''Development of focusing monochromators for neutron scattering instruments'' (DE-FG02-96ER45599)

    SciTech Connect

    Popovici, Mihai P.

    2000-03-21

    Bent crystal monochromators were developed for the neutron scattering community: (1) doubly focusing bulk silicon, for high-resolution neutron diffraction; (2) doubly focusing multi-wafer silicon, for residual stress instruments; (3) silicon-wafer: (a) with pneumatic spherical bending, (b) with mechanical cylindrical bending, (c) with mechanical two-dimensional bending, for high-resolution three-axis spectrometry; (4) doubly focusing multi-wafer silicon, for epithermal (eV range) neutrons; (5) doubly focusing composite pyrolytic graphite (low-cost), for high-flux applications.

  1. New method of a "point-like" neutron source creation based on sharp focusing of high-current deuteron beam onto deuterium-saturated target for neutron tomography

    NASA Astrophysics Data System (ADS)

    Golubev, S.; Skalyga, V.; Izotov, I.; Sidorov, A.

    2017-02-01

    A possibility of a compact powerful point-like neutron source creation is discussed. Neutron yield of the source based on deuterium-deuterium (D-D) reaction is estimated at the level of 1011 s‑1 (1013 s‑1 for deuterium-tritium reaction). The fusion takes place due to bombardment of deuterium- (or tritium) loaded target by high-current focused deuterium ion beam with energy of 100 keV. The ion beam is formed by means of high-current quasi-gasdynamic ion source of a new generation based on an electron cyclotron resonance (ECR) discharge in an open magnetic trap sustained by powerful microwave radiation. The prospects of proposed generator for neutron tomography are discussed. Suggested method is compared to the point-like neutron sources based on a spark produced by powerful femtosecond laser pulses.

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

    NASA Astrophysics Data System (ADS)

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

    2007-03-01

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

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

    SciTech Connect

    Koren, S; Veltchev, I; Furhang, E

    2014-06-01

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

  4. X-ray mapping in electron-beam instruments.

    PubMed

    Friel, John J; Lyman, Charles E

    2006-02-01

    This review traces the development of X-ray mapping from its beginning 50 years ago through current analysis procedures that can reveal otherwise obscure elemental distributions and associations. X-ray mapping or compositional imaging of elemental distributions is one of the major capabilities of electron beam microanalysis because it frees the operator from the necessity of making decisions about which image features contain elements of interest. Elements in unexpected locations, or in unexpected association with other elements, may be found easily without operator bias as to where to locate the electron probe for data collection. X-ray mapping in the SEM or EPMA may be applied to bulk specimens at a spatial resolution of about 1 microm. X-ray mapping of thin specimens in the TEM or STEM may be accomplished at a spatial resolution ranging from 2 to 100 nm, depending on specimen thickness and the microscope. Although mapping has traditionally been considered a qualitative technique, recent developments demonstrate the quantitative capabilities of X-ray mapping techniques. Moreover, the long-desired ability to collect and store an entire spectrum at every pixel is now a reality, and methods for mining these data are rapidly being developed.

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

    PubMed

    Martín, Guido; Abrahantes, Arian

    2004-05-01

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

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

    SciTech Connect

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

    2007-02-15

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

  7. SU-E-T-195: Commissioning the Neutron Production of a Varian TrueBeam Linac

    SciTech Connect

    Irazola, L; Brualla, L; Rosello, J; Terron, JA; Sanchez-Nieto, B; Bedogni, R; Sanchez-Doblado, F

    2015-06-15

    Purpose: The purpose of this work is the characterization of a new Varian TrueBeam™ facility in terms of neutron production, in order to estimate neutron equivalent dose in organs during radiotherapy treatments. Methods: The existing methodology [1] was used with the reference SRAMnd detector, calibrated in terms of thermal neutron fluence at the reference field operated by PTB (Physikalisch-Technische-Bundesanstalt) at the GeNF (Geesthacht-Neutron-Facility) with the GKSS reactor FRG-1 [2]. Thermal neutron fluence for the 5 available possibilities was evaluated: 15 MV and 10&6 MV with and without Flattening Filter (FF and FFF, respectively). Irradiation conditions are as described in [3]. In addition, three different collimator-MLC configurations were studied for 15 MV: (a) collimator of 10×10 cm{sup 2} and MLC fully retracted (reference), (b) field sizes of 20×20 cm{sup 2} and 10×10 cm{sup 2} for collimator and MLC respectively, and (c) collimator and MLC aperture of 10×10 cm{sup 2}. Results: Thermal fluence rate at the “reference point” [3], as a consequence of the neutron production, obtained for (a) conformation in 15 MV is (1.45±0.11) x10{sup 4} n•cm{sup 2}/MU. Configurations (b) and (c) gave fluences of 96.6% and 97.8% of the reference (a). Neutron production decreases up to 8.6% and 5.7% for the 10 MV FF and FFF beams, respectively. Finally, it decreases up to 2.8% and 0.1% for the 6 MV FF and FFF modes, respectively. Conclusion: This work evaluates thermal neutron production of Varian TrueBeam™ system for organ equivalent dose estimation. The small difference in collimator-MLC configuration shows the universality of the methodology [3]. A decrease in this production is shown when decreasing energy from 15 to 10 MV and an almost negligible production was found for 6 MV. Moreover, a lower neutron contribution is observed for the FFF modes.[1]Phys Med Biol,2012;57:6167–6191.[2]Radiat Meas,2010;45:1513–1517.[3]Med Phys,2015;42:276–281.

  8. Elemental characterization of Hazm El-Jalamid phosphorite by instrumental neutron activation analysis.

    PubMed

    El-Taher, A; Khater, Ashraf E M

    2016-08-01

    Instrumental neutron activation analyses (INAA) have been used to achieve accurate knowledge about the elemental analysis of phosphate ore deposits collected from Hazm El-Jalamid Northeast of Saudi Arabia. The samples were prepared for irradiation by thermal neutrons using a thermal neutron flux of 7×10(12)ncm(-2)s(-1) at ACT Lab Canada. The concentrations of 19 elements were determined. These included 12 major, minor and trace elements (Au, As, Ba, Br, Cr, Mo, Sb, Sc, Sr, Th, U and Zn) and 7 rare earth elements (REEs) (La, Ce, Nd, Sm, Eu, Yb and Lu). Major elements (Si, Al, Fe, Ca, Mg, Na, K, Cr, Ti, Mn, P, Sr and Ba) were determined using an inductively coupled plasma-mass spectrometer (ICP-MS). The comparison of the concentration of U and the REEs in the Hazm El-Jalamid phosphate samples with those of the Umm Wu'al phosphate from Saudi Arabia and El-Sibayia and El Hamrawein phosphate from Egypt shows that the contents of U and REEs are clearly higher in the Umm Wu'al, El-Sibayia and El Hamrawein phosphates than in the Hazm El-Jalamid phosphate samples. The results of major, trace elements, uranium and rare earth elements (REE) from El Jalamid phosphate have been compared with the global values of these elements. The concentrations for most of the elements studied are lower than the concentrations reported in the literature. The acquired data will serve as a reference for the follow-up studies to assess the agronomic effectiveness of the Hazm El-Jalamid phosphate rocks.

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

    PubMed

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

    2007-09-01

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

  10. Instrumental neutron activation analysis data for cloud-water particulate samples, Mount Bamboo, Taiwan

    USGS Publications Warehouse

    Lin, Neng-Huei; Sheu, Guey-Rong; Wetherbee, Gregory A.; Debey, Timothy M.

    2013-01-01

    Cloud water was sampled on Mount Bamboo in northern Taiwan during March 22-24, 2002. Cloud-water samples were filtered using 0.45-micron filters to remove particulate material from the water samples. Filtered particulates were analyzed by instrumental neutron activation analysis (INAA) at the U.S. Geological Survey National Reactor Facility in Denver, Colorado, in February 2012. INAA elemental composition data for the particulate materials are presented. These data complement analyses of the aqueous portion of the cloud-water samples, which were performed earlier by the Department of Atmospheric Sciences, National Central University, Taiwan. The data are intended for evaluation of atmospheric transport processes and air-pollution sources in Southeast Asia.

  11. Chemical characterization of gas- and oil-bearing shales by instrumental neutron activation analysis

    USGS Publications Warehouse

    Frost, J.K.; Koszykowski, R.F.; Klemm, R.C.

    1982-01-01

    The concentration of As, Ba, Ca, Co, Cr, Cs, Dy, Eu, Fe, Ga, Hf, K, La, Lu, Mn, Mo, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, Yb, and Zn were determined by instrumental neutron activation analysis in block shale samples of the New Albany Group (Devonian-Mississippian) in the in the Illinois Basin. Uranium content of the samples was as high as 75 ppm and interfered in the determination of samarium, molybdenum, barium and cerium. In the determination of selenium a correction was made for interference from tantalum. U, As, Co, Mo, Ni and Sb as well as Cu, V and pyritic sulphur which were determined by other methods, were found to correlate positively with the organic carbon content of the samples. ?? 1982 Akade??miai Kiado??.

  12. Note: Detector collimators for the nanoscale ordered materials diffractometer instrument at the Spallation Neutron Source

    DOE PAGES

    Tamalonis, A.; Weber, J. K. R.; Neuefeind, J. C.; ...

    2015-09-09

    We constructed and tested five neutron collimator designs using the nanoscale ordered materials diffractometer (NOMAD) instrument. Collimators were made from High Density PolyEthylene (HDPE) or 5% borated HDPE. In all cases, collimators improved the signal to background ratio and reduced detection of secondary scattering. Moreover, in the Q-range 10-20 Å-1, signal to background ratio improved by factors of approximately 1.6 and 2.0 for 50 and 100 mm deep collimators, respectively. In the Q-range 40-50 Å-1, the improvement factors were 1.8 and 2.7. Secondary scattering as measured at Q similar to 9.5 Å-1 was significantly decreased when the collimators were installed.

  13. Hair-zinc levels determination in Algerian psoriatics using Instrumental Neutron Activation Analysis (INAA).

    PubMed

    Mansouri, A; Hamidatou Alghem, L; Beladel, B; Mokhtari, O E K; Bendaas, A; Benamar, M E A

    2013-02-01

    Psoriasis is a multifactorial skin disease with an unknown etiology. Zinc has a positive impact on psoriasis. The aim of this study is to determine hair-zinc concentration in Algerian psoriatics. 58 psoriatics and 31 normal controls of both genders were selected. Hair zinc levels were determined using Instrumental Neutron Activation Analysis technique (INAA). Student's t-test and One-Way ANOVA were applied. The average zinc concentration for controls and patients were 152 ± 53 μg/g and 167 ± 52 μg/g respectively. They are not significantly different (p>0.05). Zn concentration for males and females controls and patients were 171±27 μg/g, 151±37 μg/g and 145 ± 59 μg/g, 178 ± 58 μg/g respectively. However, for females we have observed a significant difference (p<0.05).

  14. Differential Die-Away Instrument: Report on Fuel Assembly Mock-up Measurements with Neutron Generator

    SciTech Connect

    Goodsell, Alison Victoria; Swinhoe, Martyn Thomas; Henzl, Vladimir; Rael, Carlos D.; Desimone, David J.

    2014-09-18

    Fresh fuel experiments for the differential die-away (DDA) project were performed using a DT neutron generator, a 15x15 PWR fuel assembly, and nine 3He detectors in a water tank inside of a shielded cell at Los Alamos National Laboratory (LANL). Eight different fuel enrichments were created using low enriched (LEU) and depleted uranium (DU) dioxide fuel rods. A list-mode data acquisition system recorded the time-dependent signal and analysis of the DDA signal die-away time was performed. The die-away time depended on the amount of fissile material in the fuel assembly and the position of the detector. These experiments were performed in support of the spent nuclear fuel Next Generation Safeguards Initiative DDA project. Lessons learned from the fresh fuel DDA instrument experiments and simulations will provide useful information to the spent fuel project.

  15. Note: Detector collimators for the nanoscale ordered materials diffractometer instrument at the Spallation Neutron Source

    SciTech Connect

    Tamalonis, A.; Weber, J. K. R. Alderman, O. L. G.; Neuefeind, J. C.; Carruth, J.; Skinner, L. B.; Benmore, C. J.

    2015-09-15

    Five neutron collimator designs were constructed and tested at the nanoscale ordered materials diffractometer (NOMAD) instrument. Collimators were made from High Density PolyEthylene (HDPE) or 5% borated HDPE. In all cases, collimators improved the signal to background ratio and reduced detection of secondary scattering. In the Q-range 10-20 Å{sup −1}, signal to background ratio improved by factors of approximately 1.6 and 2.0 for 50 and 100 mm deep collimators, respectively. In the Q-range 40-50 Å{sup −1}, the improvement factors were 1.8 and 2.7. Secondary scattering as measured at Q ∼ 9.5 Å{sup −1} was significantly decreased when the collimators were installed.

  16. Note: Detector collimators for the nanoscale ordered materials diffractometer instrument at the Spallation Neutron Source

    SciTech Connect

    Tamalonis, A.; Weber, J. K. R.; Neuefeind, J. C.; Carruth, J.; Skinner, L. B.; Alderman, O. L. G.; Benmore, C. J.

    2015-09-09

    We constructed and tested five neutron collimator designs using the nanoscale ordered materials diffractometer (NOMAD) instrument. Collimators were made from High Density PolyEthylene (HDPE) or 5% borated HDPE. In all cases, collimators improved the signal to background ratio and reduced detection of secondary scattering. Moreover, in the Q-range 10-20 Å-1, signal to background ratio improved by factors of approximately 1.6 and 2.0 for 50 and 100 mm deep collimators, respectively. In the Q-range 40-50 Å-1, the improvement factors were 1.8 and 2.7. Secondary scattering as measured at Q similar to 9.5 Å-1 was significantly decreased when the collimators were installed.

  17. Recent development of the Multi-Grid detector for large area neutron scattering instruments

    SciTech Connect

    Guerard, Bruno

    2015-07-01

    Most of the Neutron Scattering facilities are committed in a continuous program of modernization of their instruments, requiring large area and high performance thermal neutron detectors. Beside scintillators detectors, {sup 3}He detectors, like linear PSDs (Position Sensitive Detectors) and MWPCs (Multi-Wires Proportional Chambers), are the most current techniques nowadays. Time Of Flight instruments are using {sup 3}He PSDs mounted side by side to cover tens of m{sup 2}. As a result of the so-called '{sup 3}He shortage crisis{sup ,} the volume of 3He which is needed to build one of these instruments is not accessible anymore. The development of alternative techniques requiring no 3He, has been given high priority to secure the future of neutron scattering instrumentation. This is particularly important in the context where the future ESS (European Spallation Source) will start its operation in 2019-2020. Improved scintillators represent one of the alternative techniques. Another one is the Multi-Grid introduced at the ILL in 2009. A Multi-Grid detector is composed of several independent modules of typically 0.8 m x 3 m sensitive area, mounted side by side in air or in a vacuum TOF chamber. One module is composed of segmented boron-lined proportional counters mounted in a gas vessel; the counters, of square section, are assembled with Aluminium grids electrically insulated and stacked together. This design provides two advantages: First, magnetron sputtering techniques can be used to coat B{sub 4}C films on planar substrates, and second, the neutron position along the anode wires can be measured by reading out individually the grid signals with fast shaping amplifiers followed by comparators. Unlike charge division localisation in linear PSDs, the individual readout of the grids allows operating the Multi-Grid at a low amplification gain, hence this detector is tolerant to mechanical defects and its production accessible to laboratories equipped with standard

  18. Instrumental neutron activation analysis of brain aluminum in Alzheimer disease and aging.

    PubMed

    Markesbery, W R; Ehmann, W D; Hossain, T I; Alauddin, M; Goodin, D T

    1981-12-01

    Instrumental neutron activation analysis procedures were used to determine the aluminum content of various brain regions in histologically verified Alzheimer disease (AD) and in controls. The grand mean aluminum level for 74 AD specimens was 0.372 +/- 0.058 microgram/gm and for 137 adult controls, 0.467 +/- 0.033 microgram/gm, both on a wet weight basis. No difference was found at the bulk sample level between AD and adult controls, corrected for age and sex, or when frontal, temporal, and hippocampal specimens were compared. Control specimens (infancy to 85 years) showed an increase in brain aluminum concentration with age. Comparison of freeze-dried to wet weight ratios of AD and controls revealed a small increase in water content in AD brains.

  19. Study of essential elements in cattle tissues from a tropical country using instrumental neutron activation analysis.

    PubMed

    Avelar, Artur Canella; Menezes, Maria Angela de B C; Veado, Julio Cesar C

    2002-09-01

    There has been increasing interest in the elemental composition of animal tissues to support health and nutritional studies. Determining the elemental concentration in cattle tissues is especially important because these materials are used for multipurpose objectives such as the assessment of animal health, the quality of human foods consumed, and as a potential environmental biomonitor. Chromium, copper, sodium, potassium, iron, and zinc levels were determined in bovine tissues--kidney, liver and muscle--from cattle bred and raised in a potentially metal contaminated region because of mineral activities. The Brazilian data were obtained using k0-instrumental neutron activation analysis, performed at the Nuclear Development Technology Centre/Nuclear Energy National Commission (CDTN/CNEN) in Minas Gerais State. The values of international organizations and the Brazilian analytical data are compatible. This study indicates that the nuclear technique is an efficient tool to determine elemental concentration in animal biological samples.

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

    NASA Astrophysics Data System (ADS)

    Kriske, Richard M.

    2016-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    SciTech Connect

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

    2010-08-04

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

  3. Monte-Carlo investigation of radiation beam quality of the CRNA neutron irradiator for calibration purposes.

    PubMed

    Mazrou, Hakim; Sidahmed, Tassadit; Allab, Malika

    2010-10-01

    An irradiation system has been acquired by the Nuclear Research Center of Algiers (CRNA) to provide neutron references for metrology and dosimetry purposes. It consists of an (241)Am-Be radionuclide source of 185 GBq (5Ci) activity inside a cylindrical steel-enveloped polyethylene container with radially positioned beam channel. Because of its composition, filled with hydrogenous material, which is not recommended by ISO standards, we expect large changes in the physical quantities of primary importance of the source compared to a free-field situation. Thus, the main goal of the present work is to fully characterize neutron field of such special delivered set-up. This was conducted by both extensive Monte-Carlo calculations and experimental measurements obtained by using BF(3) and (3)He based neutron area dosimeters. Effects of each component present in the bunker facility of the Algerian Secondary Standard Dosimetry Laboratory (SSDL) on the energy neutron spectrum have been investigated by simulating four irradiation configurations and comparison to the ISO spectrum has been performed. The ambient dose equivalent rate was determined based upon a correct estimate of the mean fluence to ambient dose equivalent conversion factors at different irradiations positions by means of a 3-D transport code MCNP5. Finally, according to practical requirements established for calibration purposes an optimal irradiation position has been suggested to the SSDL staff to perform, in appropriate manner, their routine calibrations.

  4. 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

    2016-07-08

    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.

  5. 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

    2016-07-01

    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. PACS number(s): 87

  6. First negative ion beam measurement by the Short-Time Retractable Instrumented Kalorimeter Experiment (STRIKE)

    SciTech Connect

    Serianni, G. De Muri, M.; Veltri, P.; Bonomo, F.; Chitarin, G.; Pasqualotto, R.; Pavei, M.; Rizzolo, A.; Valente, M.; Muraro, A.; Franzen, P.; Ruf, B.; Schiesko, L.

    2014-02-15

    The Source for Production of Ion of Deuterium Extracted from Rf plasma (SPIDER) test facility is under construction in Padova to optimise the operation of the beam source of ITER neutral beam injectors. The SPIDER beam will be characterised by the instrumented calorimeter STRIKE, whose main components are one-directional carbon-fibre-carbon-composite tiles. A small-scale version of the entire system has been employed in the BAvarian Test MAchine for Negative ions (BATMAN) testbed by arranging two prototype tiles in the vertical direction. The paper presents a description of the mini-STRIKE system and of the data analysis procedures, as well as some results concerning the BATMAN beam under varying operating conditions.

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

    NASA Astrophysics Data System (ADS)

    Faghihi, F.; Khalili, S.

    2013-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  9. 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.

  10. Determination of twenty-nine elements in eight argonne premium coal samples by instrumental neutron activation analysis

    USGS Publications Warehouse

    Palmer, C.A.

    1990-01-01

    Twenty-nine elements have been determined in triplicate splits of the eight Argonne National Laboratory Premium Coal Samples by instrumental neutron activtaion analysis. Data for control samples NBS 1633 (fly ash) and NBS 1632b are also reported. The factors that could lead to errors in analysis for these samples, such as spectral overlaps, low sensitivity, and interfering nuclear reactions, are discussed.

  11. Radiobiological intercomparison of two clinical neutron beams using the regeneration of mouse intestinal crypts.

    PubMed

    Böhm, L; Gueulette, J; Jones, D T; Beauduin, M; Vynckier, S; de Roubaix, S; Yudelev, M; Slabbert, J P; Wambersie, A

    1990-03-01

    Determination of dose modification factor greatly facilitates the introduction of clinically proven neutron therapy schedules at new installations. We have compared the biological performance of the p(66)+Be neutron facility at Faure, South Africa, with the established p(65)+Be installation at Louvain-la-Neuve, Belgium. Filtration, D gamma/DT, dose rate and HVT 5/15 for the Louvain and Faure beam are: 2 cm, 2.5 cm polyethylene; 3%, 5%; 0.2 Gy/min, 0.4 Gy/min; and 20 cm and 19 cm respectively. Dosimetry was done in A-150 plastic. Irradiation of BALB/C mice was carried on according to the dose accumulation method in a perspex phantom at 5 cm depth and at an SSD of 150 cm at a field size of 28 X 28 cm2. Sections of the jejunum were prepared at each centre and analyzed by both. The RBE of the Faure beam determined at a survival level of 50 crypts ranged from 1.64 to 1.69. The dose modification factor RBE of the Louvain beam given by Beauduin et al. was 1.61 +/- 0.14. The dose modification factor of the Faure beam relative to the Louvain beam is thus 1.03 +/- 0.13 which could be expected from the similarity of the physical characteristics. Independent RBE measurements in a variety of systems also suggest similar biological properties. The depth variation of the RBE was found to be 4% (mouse gut) using 3 cm polyethylene filter over the depth range of 2.5 to 13.5 cm. This is in agreement with microdosimetry measurements using polyethylene filters of various thicknesses and with V79 measurements reported by Slabbert et al.

  12. Neutron diffraction of titanium aluminides formed by continuous electron-beam treatment

    NASA Astrophysics Data System (ADS)

    Valkov, S.; Neov, D.; Luytov, D.; Petrov, P.

    2016-03-01

    Ti-Al-based alloys were produced by hybrid electron-beam technologies. A composite Ti-Al film was deposited on a Ti substrate by electron-beam evaporation (EBE), followed by electron-beam treatment (EBT) by a continuously scanned electron beam. The speed of the specimens motion during the EBT were V 1 = 1 cm/sec and V 2 = 5 cm/sec, in order to realize two different alloying mechanisms -- by surface melting and by electron-beam irradiation without melting the surface. The samples prepared were characterized by XRD and neutron diffraction to study the crystal structure on the surface and in depth. SEM/EDX analysis was conducted to explore the surface structure and analyze the chemical composition. Nanoindentation measurements were also carried out. No intermetallic phases were registered in the sample treated at velocity V 1, while the sample treated at V 2 exhibited a Ti3Al/TiAl structure on the surface, transformed to Ti/TiAl in depth. The nanoindentation test demonstrated a significant negative hardness gradient from the surface to the depth of the sample.

  13. Designing a minimum-functionality neutron and gamma measurement instrument with a focus on authentication

    SciTech Connect

    Karpius, Peter J; Williams, Richard B

    2009-01-01

    During the design and construction of the Next-Generation Attribute-Measurement System, which included a largely commercial off-the-shelf (COTS), nondestructive assay (NDA) system, we realized that commercial NDA equipment tends to include numerous features that are not required for an attribute-measurement system. Authentication of the hardware, firmware, and software in these instruments is still required, even for those features not used in this application. However, such a process adds to the complexity, cost, and time required for authentication. To avoid these added authenticat ion difficulties, we began to design NDA systems capable of performing neutron multiplicity and gamma-ray spectrometry measurements by using simplified hardware and software that avoids unused features and complexity. This paper discusses one possible approach to this design: A hardware-centric system that attempts to perform signal analysis as much as possible in the hardware. Simpler processors and minimal firmware are used because computational requirements are kept to a bare minimum. By hard-coding the majority of the device's operational parameters, we could cull large sections of flexible, configurable hardware and software found in COTS instruments, thus yielding a functional core that is more straightforward to authenticate.

  14. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    SciTech Connect

    KOETZLE,T.F.

    2001-03-13

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  15. An integrated optics beam combiner for the second generation VLTI instruments

    NASA Astrophysics Data System (ADS)

    Benisty, M.; Berger, J.-P.; Jocou, L.; Labeye, P.; Malbet, F.; Perraut, K.; Kern, P.

    2009-05-01

    Context: Recently, an increasing number of scientific publications making use of images obtained with near-infrared long-baseline interferometry have been produced. The technique has reached, at last, a technical maturity level that opens new avenues for numerous astrophysical topics requiring milli-arc-second model-independent imaging. The Very Large Telescope Interferometer (VLTI) will soon be equipped with instruments able to combine between four and six telescopes. Aims: In the framework of the VLTI second generation instruments Gravity and VSI, we propose a new beam combining concept using integrated optics (IO) technologies with a novel ABCD-like fringe encoding scheme. Our goal is to demonstrate that IO-based combinations bring considerable advantages in terms of instrumental design and performance. We therefore aim at giving a full characterization of an IO beam combiner in order to establish its performance and check its compliance with the specifications of an imaging instrument. Methods: For this purpose, prototype IO beam combiners have been manufactured and laboratory measurements were made in the H band with a dedicated testbed, simulating a four-telescope interferometer. We studied the beam combiners through the analysis of throughput, instrumental visibilities, phases and closure phases in wide band as well as with spectral dispersion. Study of the polarization properties was also carried out. Results: We obtain competitive throughput (65%), high and stable instrumental contrasts (from 80% in wide band up to 100% ± 1% with spectral dispersion), stable but non-zero closure phases (e.g. 115° ± 2°) which we attribute to internal optical path differences (OPD) that can be calibrated. We validate a new static and an achromatic phase shifting IO function close to the nominal 90° value (e.g. 80° ± 1°). All these observables show limited chromaticity over the H band range. Conclusions: Our results demonstrate that such ABCD-like beam combiners are

  16. Development of an instrument for non-destructive identification of Unexploded Ordnance using tagged neutrons - a proof of concept study

    SciTech Connect

    Mitra, S.; Dioszegi, I.

    2011-10-23

    Range clearance operations at munitions testing grounds must discriminate Unexploded Ordnance (UXO) from clutter items and distinguish UXO filled with High Explosives (HE) from those with inert fillers. Non-destructive technologies are thus necessary for the cost-effective disposal of UXO during remediation of such sites. The only technique showing promise so far for the non-destructive elemental characterization of UXO fillers utilizes neutron interactions with the material to detect carbon (C), nitrogen (N) and oxygen (O) which have unique ratios in HE. However, several unresolved issues hinder the wide application of this potentially very suitable technique. The most important one is that neutrons interact with all surrounding matter in addition to the interrogated material, leading to a very high gamma-ray background in the detector. Systems requiring bulky shielding and having poor signal-to-noise ratios (SNRs) for measuring elements are unsuitable for field deployment. The inadequacies of conventional neutron interrogation methods are overcome by using the tagged-neutron approach, and the availability of compact sealed neutron generators exploiting this technique offers field deployment of non-intrusive measurement systems for detecting threat materials, like explosives and drugs. By accelerating deuterium ions into a tritium target, the subsequent fusion reaction generates nearly back-to-back emissions of neutrons and alpha particles of energy 14.1 and 3.5 MeV respectively. A position-sensitive detector recognizes the associated alpha particle, thus furnishing the direction of the neutron. The tagged neutrons interact with the nuclei of the interrogated object, producing element-specific prompt gamma-rays that the gamma detectors recognize. Measuring the delay between the detections of the alpha particle and the gamma-ray determines where the reaction occurred along the axis of the neutron beam (14.1 MeV neutrons travel at 5 cm/nanosecond, while gamma rays

  17. Multi-beam Lidar Instrument Design, Measurement Capabilities, and Technical Readiness

    NASA Astrophysics Data System (ADS)

    Blair, B.; Ranson, J.; Dubayah, R.; Coyle, B.; Salerno, C.

    2007-12-01

    A multi-beam Laser Altimeter has been designed and studied at NASA Goddard Space Flight Center and the critical technologies have developed and tested resulting in a mature and technically ready instrument approach. The instrument consists of three separate beams each providing a near-contiguous profile of 25 m diameter laser footprints. The across-track separation of the beams can be <1 km to as much as ~5 km. A return waveform is collected for each footprint and the system has sufficient Signal-to-Noise Ratio (SNR) to penetrate dense (i.e. 98-99% cover) canopies in relatively clear sky conditions and can penetrate clouds to provide precise topography over unvegetated surfaces. The Multi-beam Laser Altimeter design includes a high-quality GPS receiver for providing precise orbital position information and a state-of-the-art Star Tracker and Inertial Measurement Unit to provide precise and accurate laser beam pointing knowledge. The digitizer-based ranging system will provide ranging to bare surfaces with ~3 cm range precision. The return waveforms will also provide vegetation height measurements with ~1 m of accuracy. The laser transmitters have been fully developed, characterize, and tested. Engineering Test Unit has been built at NASA/GSFC for environmental testing. Test units of the laser demonstrated 5 Billion shots without damage and diode testing indicates lifetimes of ~10 Billion shots per laser can be expected. A new waveform digitizer has been developed with improvements in sampling rate and dynamic range over the ICESat digitizer system, thus allowing higher quality waveforms to be collected, which is critical importantly for vegetation studies. This multi-beam Lidar design is the basis for the Lidar on the DESDynI (Deformation, Ecosystem Structure, and Dynamics of Ice) mission described in the NRC Decadal Survey Report that consists of a Multi-beam Lidar and an L-band InSAR to be launched in the 2010-2013 timeframe.

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

    SciTech Connect

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

    2008-11-01

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

  19. Italian neutron sources

    NASA Astrophysics Data System (ADS)

    Prata, M.; Alloni, D.; De Felice, P.; Palomba, M.; Pietropaolo, A.; Pillon, M.; Quintieri, L.; Santagata, A.; Valente, P.

    2014-11-01

    Many research activities, instrumental analysis, studies of radiation damage, etc., require neutron sources. The main neutron sources present in Italy are described in three different sections: nuclear research reactors, accelerator driven, and metrology stations. The nuclear research reactors of LENA (University of Pavia) and ENEA Casaccia are described in terms of irradiation facilities available, neutron flux for each of them and the main activities carried out by each research centre. In the second section, the Frascati Neutron Generator (FNG), the Frascati Beam-Test Facility (BTF) and their main features are reported. In the last section there is a detailed description of the institutional role and the main activities carried out in the field of neutron metrology by the National Institute for Metrology of Ionizing Radiation (INMRI) with a brief description of neutron sources of which the institute is endowed.

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

    SciTech Connect

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

    1997-12-01

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

  1. Characterization of HPGe gamma spectrometric detectors systems for Instrumental Neutron Activation Analysis (INAA) at the Colombian Geological Survey

    NASA Astrophysics Data System (ADS)

    Sierra, O.; Parrado, G.; Cañón, Y.; Porras, A.; Alonso, D.; Herrera, D. C.; Peña, M.; Orozco, J.

    2016-07-01

    This paper presents the progress made by the Neutron Activation Analysis (NAA) laboratory at the Colombian Geological Survey (SGC in its Spanish acronym), towards the characterization of its gamma spectrometric systems for Instrumental Neutron Activation Analysis (INAA), with the aim of introducing corrections to the measurements by variations in sample geometry. Characterization includes the empirical determination of the interaction point of gamma radiation inside the Germanium crystal, through the application of a linear model and the use of a fast Monte Carlo N-Particle (MCNP) software to estimate correction factors for differences in counting efficiency that arise from variations in sample density between samples and standards.

  2. 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°.

  3. Production of very neutron-rich nuclei with a {sup 76}Ge beam

    SciTech Connect

    Tarasov, O. B.; Portillo, M.; Baumann, T.; Bazin, D.; Ginter, T. N.; Hausmann, M.; Pereira, J.; Stolz, A.; Amthor, A. M.; Gade, A.; Nettleton, A.; Sherrill, B. M.; Thoennessen, M.; Inabe, N.; Kubo, T.; Morrissey, D. J.

    2009-09-15

    Production cross sections for neutron-rich nuclei from the fragmentation of a {sup 76}Ge beam at 132 MeV/u were measured. The longitudinal momentum distributions of 34 neutron-rich isotopes of elements 13{<=}Z{<=}27 were scanned using a novel experimental approach of varying the target thickness. Production cross sections with beryllium and tungsten targets were determined for a large number of nuclei, including 15 isotopes first observed in this work. These are the most neutron-rich nuclides of the elements 17{<=}Z{<=}25 ({sup 50}Cl, {sup 53}Ar, {sup 55,56}K, {sup 57,58}Ca, {sup 59,60,61}Sc, {sup 62,63}Ti, {sup 65,66}V, {sup 68}Cr, and {sup 70}Mn). A one-body Q{sub g} systematics is used to describe the production cross sections based on thermal evaporation from excited prefragments. Some of the fragments near {sup 58}Ca show anomalously large production cross sections.

  4. Study for s-process using neutron beam provided from ANNRI of J-PARC

    NASA Astrophysics Data System (ADS)

    Hayakawa, Takehioto; Toh, Yosuke; Kimura, Akira; Nakamura, Shoji; Shizuma, Toshiyuki; Harada, Hideo

    2016-06-01

    Most isotopes heavier than iron are synthesized by the slow neutron capture reaction process (s-process) in stars. Isomers in stable isotopes have sometimes an important role as a branching point in nucleosynthesis flow in the s-process. An isomer with a half-life of 14.1 y in 113Cd is a branching point from which a nucleosynthesis flow reaches to a rare isotope 115Sn. The astrophysical origin of 115Sn has remained still an open question. The s-process abundance of 115Sn depends on the ratio of the 112Cd(n, γ) 113Cdm reaction cross section to the 112Cd(n, γ) 113Cdgs reaction cross section. However, the isomer production ratio following the neutron capture reaction has not been measured in the energy region higher than the thermal energy. An intense neutron beam experimental system, ANNRI, in J-PARC has a high purity germanium (HPGe) detector system consisting of two cluster detectors. We have measured γ-rays decaying to the ground state and the isomer using the HPGe detectors in conjunction with a time-offlight method at ANNRI.

  5. 3He spin filter based polarized neutron capability at the NIST Center for Neutron Research

    NASA Astrophysics Data System (ADS)

    Chen, W. C.; Gentile, T. R.; Erwin, R.; Watson, S.; Ye, Q.; Krycka, K. L.; Maranville, B. B.

    2014-07-01

    A 3He neutron spin filter (NSF) program for polarized neutron scattering was launched in 2006 as part of the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) Expansion Initiative. The goal of the project was to enhance the NCNR polarized neutron measurement capabilities. Benefitting from more than a decade's development of spin-exchange optical pumping (SEOP) at NIST, we planned to employ SEOP based 3He neutron spin filters for the polarized neutron scattering community. These 3He NSF devices were planned for use on different classes of polarized neutron instrumentation at the NCNR, including triple-axis spectrometers (TAS), small-angle neutron scattering instruments (SANS), reflectometers, and wide-angle polarization analysis. Among them, the BT-7 thermal TAS, NG-3 SANS, and MAGIK reflectometer have already been in the user program for routine polarized beam experiments. Wide-angle polarization analysis on Multi-Axis Crystal Spectrometer (MACS) has been developed for user experiments. We describe briefly the SEOP systems dedicated for polarized beam experiments and polarizing neutron development for each instrument class. We summarize the current status and polarized neutronic performance for each instrument. We present a 3He NSF hardware and software interface to allow for synchronization of 3He polarization inversion (neutron spin flipping) and free-induction decay (FID) nuclear magnetic resonance (NMR) measurements with neutron data collection.

  6. Neutronics analysis of three beam-filter assemblies for an accelerator-based BNCT facility

    SciTech Connect

    Bleuel, D.L.; Costes, S.V.; Donahue, R.J.; Ludewigt, B.A.

    1997-08-01

    Three moderator materials, AlF{sub 3}/Al, D{sub 2}O and LiF, have been analyzed for clinical usefulness using the reaction {sup 7}Li(p,n) as an accelerator driven neutron source. Proton energies between 2.1 MeV and 2.6 MeV have been investigated. Radiation transport in the reflector/moderator assembly is simulated using the MCNP program. Depth-dose distributions in a head phanton are calculated with the BNCT-RTPE patient treatment planning program from INEEL using the MCNP generated neutron and photon spectra as the subsequent source. Clinical efficacy is compared using the current BMRR protocol for all designs. Depth-dose distributions are compared for a fixed normal tissue tolerance dose of 12.5 Gy-Eq. Radiation analyses also include a complete anthropomorphic phantom. Results of organ and whole body dose components are presented for several designs. Results indicate that high quality accelerator beams may produce clinically favorable treatments to deep-seated tumors when compared to the BMRR beam. Also discussed are problems identified in comparing accelerator and reactor based designs using in-air figures of merit as well as some results of spectrum-averaged RBE`s.

  7. Analyses of a Cantilever-Beam Based Instrument for Evaluating the Development of Polymerization Stresses

    PubMed Central

    Chiang, Martin Y.M.; Giuseppetti, Anthony A. M.; Qian, Jing; Dunkers, Joy P.; Antonucci, Joseph M.; Schumacher, Gary E.; Gibson, Sheng-Lin

    2011-01-01

    Polymerization stress (PS) remains one of the most critical properties of polymeric dental materials, yet methods that can accurately quantify PS has been limited in part due to the complexity of polymerization, and in part due to the instrumentation itself. In this study, we performed analytical and finite element analyses on a cantilever-beam based tensometer to evaluate shrinkage stresses during the polymerization of dental restorative composite. Results for these analyses were used to generate 1) guidelines for designing a tensometer that satisfies the necessary accuracy requirements, and 2) a formula for calculating PS and the instrument sensitivity. The PS generated by a commercial dental composite determined using our new tensometer agrees with the predicted trend when the beam length and/or specimen height is varied. An analytical solution is also derived for the vertical deflection of beam, which can be used for any combination of bending and shearing to properly calculate the PS. This work demonstrates the importance of beam dimension and component relative rigidity to the accuracy of PS evaluation. In addition, an easy-to-conduct calibration procedure is provided that is desirable for periodic tensometer recalibration. PMID:21714998

  8. Accelerator systems and instrumentation for the NuMI neutrino beam

    NASA Astrophysics Data System (ADS)

    Zwaska, Robert Miles

    The Neutrinos at the Main Injector (NuMI) neutrino beam facility began operating at the Fermi National Accelerator Laboratory in 2005. NuMI produces an intense, muon-neutrino beam to a number of experiments. Fore most of these experiments is MINOS---the Main Injector Neutrino Oscillation Search---that uses two neutrino detectors in the beam, one at Fermilab and one in northern Minnesota, to investigate the phenomenon of neutrino oscillations. NuMI is a conventional, horn-focused neutrino beam. It is designed to accept a 400 kW, 120 GeV proton beam from the Fermilab Main Injector accelerator. The proton beam is steered onto a target, producing a secondary beam of mesons which are focused into a long evacuated volume where they decay to muons and neutrinos. Pulsed toroidal magnets (horns) focus an adjustable meson momentum range. Design of the beamline and its components is challenged by the 400 kW average proton beam power. To achieve such high proton power, the Fermilab Main Injector (MI) must store and accelerate ˜ 4x1013 protons per acceleration cycle. This requires the MI to be loaded with 6 or more batches of protons from the 8 GeV Booster accelerator. Such multiple-batch injection involves a synchronization of the two machines not previously required by the Fermilab accelerators. In this dissertation, we investigate timing errors that can arise between the two accelerators, and a feedback system which enables multiple Booster transfers into the Main Injector without significant loss of beam. Using this method of synchronous transfer, the Main Injector has delivered as many as 3x1013 protons per pulse to the NuMI beam. The instrumentation to assess the quality of the neutrino beam includes arrays of radiation-tolerant ionization chambers downstream of the decay volume. These arrays detect the remnant hadrons and tertiary muons produced with the neutrinos. This thesis discusses measurements using the arrays, including diagnostics of potential beam errors and

  9. Heavy Ion Reactions with Neutron-Rich Beams - Proceedings of the Riken International Workshop

    NASA Astrophysics Data System (ADS)

    Yamaji, S.; Ishihara, M.; Takigawa, N.

    1993-11-01

    The Table of Contents for the book is as follows: * Preface * Opening Address * Fusion I * Heavy Ion Fusion at Subbarrier Energies: Progress and Questions * Angular Momentum in Heavy Ion Subbarrier Interaction * Fusion II * High Precision Fusion Excitation Function Measurements: What Can We Learn from Them? * Transfer Reactions for 16O + 144,152Sm near the Coulomb Barrier * Fusion III * Recent Theoretical Developments in the Study of Subbarrier Fusion * Direct Reaction Approach to Heavy Ion Scattering and Fusion at Energies near Coulomb Barrier * Fusion IV * Roles of Multi-Step Transfer in Fusion Process Induced by Heavy Ion Reactions * Special Session * RIKEN Accelerator Research Facility (RARF) * Fission I * Bimodal Nature of Nuclear Fission * Systematics of Isotope Production Rates: Mass Excess Dependence of Fission Products * Semiclassical Methods for the Multi-Dimensional Quantum Decay * Dynamics of Di-Nucleus Systems: Molecular Resonances * Fission II * The Competition Between Fusion-Fission and Deeply Inelastic Reactions in the Medium Mass Systems * Unstable Nuclei I * Coulomb Dissociation and Momentum Distributions for 11Li → 9Li+n+n Breakup Reactions * Unstable Nuclei II * Elastic Scattering and Fragmentation of Halo Nuclei * Secondary Reactions of Neutron-Rich Nuclei at Intermediate Energies * Life Time of Soft Dipole Excitation * Unstable Nuclei III * Shell Structure of Exotic Unstable Nuclei * Properties of Unstable Nuclei Within the Relativistic Many-Body Theory * Fusion with Unstable Nuclei * Barrier Distributions for Heavy Ion Fusion * Heavy Ion Reactions with Neutron-Rich Beams * Heavy Ion Fusion with Neutron-Rich Beams * Superheavy Elements * Study of α Decays Following 40Ar Bombardment on 238U * Production of Superheavy Elements via Fusion: What is Limiting Us? * Panel Session * Comments * List of Participants

  10. Monte Carlo simulations for the development of polarized neutron instrumentation: An overview

    NASA Astrophysics Data System (ADS)

    Zsigmond, Geza; Manoshin, Sergey; Lieutenant, Klaus; Seeger, Philip A.; Christiansen, Peter; Willendrup, Peter; Lefmann, Kim

    2007-07-01

    Handling of polarization became very important in simulations of neutron scattering. One of the very comprehensive and open-source neutron simulation package, VITESS, has been intensely involved in polarized neutron simulations. Several examples will be shown here. Another similar package NISP also contains polarization tools. McStas has implemented an initial set of routines handling polarization, as our examples will also show.

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

    PubMed

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

    2011-02-14

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

  12. Analysis and simulation of a small-angle neutron scattering instrument on a 1 MW long pulse spallation source

    SciTech Connect

    Olah, G.A.; Hjelm, R.P.; Lujan, M. Jr.

    1996-12-31

    We studied the design and performance of a small-angle neutron scattering (SANS) instrument for a proposed 1 MW, 60 Hz long pulsed spallation source at the Los Alamos Neutron Science Center (LANSCE). An analysis of the effects of source characteristics and chopper performance combined with instrument simulations using the LANSCE Monte Carlo instrument simulations package shows that the T{sub 0} chopper should be no more than 5 m from the source with the frame overlap and frame definition choppers at 5.6 and greater than 7 m, respectively. The study showed that an optimal pulse structure has an exponential decaying tail with {tau} {approx} 750 {mu}s. The Monte Carlo simulations were used to optimize the LPSS SANS, showing that an optimal length is 18 m. The simulations show that an instrument with variable length is best to match the needs of a given measurement. The performance of the optimized LPSS instrument was found to be comparable with present world standard instruments.

  13. Optimization of Neutron Spectrum in Northwest Beam Tube of Tehran Research Reactor for BNCT, by MCNP Code

    SciTech Connect

    Zamani, M.; Kasesaz, Y.; Khalafi, H.; Shayesteh, M.

    2015-07-01

    In order to gain the neutron spectrum with proper components specification for BNCT, it is necessary to design a Beam Shape Assembling (BSA), include of moderator, collimator, reflector, gamma filter and thermal neutrons filter, in front of the initial radiation beam from the source. According to the result of MCNP4C simulation, the Northwest beam tube has the most optimized neuron flux between three north beam tubes of Tehran Research Reactor (TRR). So, it has been chosen for this purpose. Simulation of the BSA has been done in four above mentioned phases. In each stage, ten best configurations of materials with different length and width were selected as the candidates for the next stage. The last BSA configuration includes of: 78 centimeters of air as an empty space, 40 centimeters of Iron plus 52 centimeters of heavy-water as moderator, 30 centimeters of water or 90 centimeters of Aluminum-Oxide as a reflector, 1 millimeters of lithium (Li) as thermal neutrons filter and finally 3 millimeters of Bismuth (Bi) as a filter of gamma radiation. The result of Calculations shows that if we use this BSA configuration for TRR Northwest beam tube, then the best neutron flux and spectrum will be achieved for BNCT. (authors)

  14. Quality assurance program for the determination of selenium in foods and diets by instrumental neutron activation

    SciTech Connect

    Zhang, W.H.; Chatt, A.

    1996-12-31

    The biological essentially of selenium for animals was first evidenced in 1957. However, it was not until 1973 that an enzyme called glutathione peroxidase was proven to be a selenoenzyme. At present, selenium is known to be a normal component of several enzymes, proteins, and some aminoacryl transfer nucleic acids. A few selenium compounds have been reported to possess anticarcinogenic properties. There is an increasing interest in understanding the role of selenium in human nutrition and metabolism. Analytical methods are being developed in several laboratories for the determination of total and species-specific selenium in whole blood, serum, urine, soft and hard tissues, food, water, proteins, etc. We have developed several instrumental neutron activation analysis (INAA) methods using the, Dalhousie University SLOWPOKE-2 reactor facility for the determination of parts-per-billion levels of selenium. These methods include cyclic INAA (CINAA) and pseudocyclic INAA (PCINAA) using both conventional and anticoincidence gamma-ray spectrometry. Considering the immense health significance, it is imperative that the selenium levels in foods and diets be measured under an extensive quality assurance program for routine monitoring purposes.

  15. Breast Milk Concentration of Rubidium in Lactating Mothers by Instrumental Neutron Activation Analysis Method

    PubMed Central

    Khatami, Seyedeh-Fatemeh; Parvaresh, Pouya; Parvaresh, Parviz; Madani Kouchak, Sara Sadat; Khorsandi, Jamshid

    2014-01-01

    Objective: Relatively little is known about the trace elements content of human milk from different countries. This has not been fully investigated especially among Iranian women. This study aimed to assess the concentration of Rubidium (Rb) as a poisonous trace element in transitional breast milk of lactating mothers living in Mashhad. Methods: Forty nursing mothers in early lactation 3 days to 15 days postpartum, free from any medical disorder and/or medication were randomly selected. We have applied Instrumental Neutron Activation Analysis (INAA) to assess the long-lived isotope trace element Rb in transitional milk of these economically moderate 18–39 year old Iranian women. Findings: The average concentration level of Rb was 32.176 ppm dry weight (min 8.660, max 107.210 ppm). No significant correlation was observed between Rb concentration and maternal weight and age (P=0.06, P=0.05 respectively) and newborns’ weight, age and sex (P=0.07, P=0.2, P=0.2 respectively). Conclusion: Although the Rubidium concentration found in this study is among the highest reported in the literature, it could not be compared to other studies because of differences in analytical performance, state of lactation, and unavailable reference ranges, so this finding needs further investigations. PMID:26019773

  16. Studies of generalized elemental imbalances in neurological disease patients using INAA (instrumental neutron activation analysis)

    SciTech Connect

    Ehmann, W.D.; Vance, D.E.; Khare, S.S.; Kasarskis, E.J.; Markesbery, W.R.

    1988-01-01

    Evidence has been presented in the literature to implicate trace elements in the etiology of several age-related neurological diseases. Most of these studies are based on brain analyses. Using instrumental neutron activation analysis (INAA), we have observed trace element imbalances in brains of patients with Alzheimer's disease, amyotrophic lateral sclerosis (ALS), and Picks's disease. The most prevalent elemental imbalances found in the brain were for bromine, mercury, and the alkali metals. In this study the authors report INAA studies of trace elements in nonneural tissues from Alzheimer's disease and ALS patients. Samples from household relatives were collected for use as controls wherever possible. Hair samples were washed according to the International Atomic Energy Agency recommended procedure. Fingernail samples were scraped with a quartz knife prior to washing by the same procedure. For ALS patients, blood samples were also collected. These data indicate that elemental imbalances in Alzheimer's disease and ALS are not restricted to the brain. Many elements perturbed in the brain are also altered in the several nonneural tissues examined to date. The imbalances in different tissues, however, are not always in the same direction. The changes observed may represent causes, effects, or simply epiphenomena. Longitudinal studies of nonneural tissues and blood, as well as tissue microprobe analyses at the cellular and subcellular level, will be required in order to better assess the role of trace elements in the etiology of these diseases.

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

    SciTech Connect

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

    2015-06-15

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

  18. Recent improvements to the DIII-D neutral beam instrumentation and control system

    SciTech Connect

    Kellman, D.H.; Hong, R.

    1997-11-01

    The DIII-D neutral beam (NB) instrumentation and control (I and C) system provides for operational control and synchronization of the eight DIII-D neutral beam injection systems, as well as for pertinent data acquisition and safety interlocking. Recently, improvements were made to the I and C system. With the replacement of the NB control computers, new signal interfacing was required to accommodate the elimination of physical operator panels, in favor of graphical user interface control pages on computer terminal screens. The program in the mode control (MC) programmable logic controller (PLC), which serves as a logic-processing interface between the NB control computers and system hardware, was modified to improve the availability of NB heating of DIII-D plasmas in the event that one or more individual beam systems suddenly become unavailable while preparing for a tokamak experimental shot sequences. An upgraded computer platform was adopted for the NB control system operator interface and new graphical user interface pages were developed to more efficiently display system status data. A failure mode of the armor tile infrared thermometers (pyrometers), which serve to terminate beam pulsing if beam shine-through overheats wall thermal shielding inside the DIII-D tokamak, was characterized such that impending failures can be detected and repairs effected to mitigate beam system down-time. The hardware that controls gas flow to the beamline neutralizer cells was upgraded to reduce susceptibility to electromagnetic interference (EMI), and interlocking was provided to terminate beam pulsing in the event of insufficient neutralizer gas flow. Motivation, implementation, and results of these improvements are presented.

  19. Computer-aided modeling of beam propagation effects in diffraction-critical spaceborne instruments

    NASA Astrophysics Data System (ADS)

    Caldwell, Martin E.; Gray, Peter F.; McNamara, Paul

    1996-08-01

    This talk concerns applications of a ray-trace model to the computation of the effect of diffraction on beam propagation. It reports the use of the technique in the design of apertures for space-borne instruments having critical diffraction properties. The modeling technique used is that of gaussian beam decomposition, a numerical beam propagation technique incorporated in a commercially available ray-trace program. The result is the powerful capability to model the optical field at any point, in systems of any geometry, with any amount of aberration. The technique is particularly useful for design problems where `non-imaging' effects are important, and examples of its use will be given. Although the computation requirements for such detailed analysis may seem daunting, the continuing increase in readily available computing power is now overcoming this drawback. The application here is to certain `diffraction-critical' situations, where the design of correctly sized apertures is needed for the control of unwanted diffraction effects. Three recent design studies are illustrated: (1) Millimeter wave imaging with off-axis reflectors. Analysis of the effects of aberration on coherent detection efficiency. (2) Long-distance beam propagation in space-borne laser interferometry. This involves the analysis of coherent detection efficiency in the presence of aberrated gaussian beams. (3) Design of a Lyot stop system for an infra-red radiometer which is to view the Earth's limb from space. Here the critical (and unwanted) diffraction is that from the bright Earth disc, lying just outside of the instrument field of view. The analysis technique is explained, and examples given of diffracted energy patterns analyzed at progressive stages in the system. It is shown how these aid the design and analysis of the systems. The aim is to show the range problems in which this method is useful, and to hopefully learn from others at the conference about other cases where such techniques

  20. Integration of a 6LilnSe2 thermal neutron detector into a CubeSat instrument

    NASA Astrophysics Data System (ADS)

    Egner, Joanna C.; Groza, Michael; Burger, Arnold; Stassun, Keivan G.; Buliga, Vladimir; Matei, Liviu; Bodnarik, Julia G.; Stowe, Ashley C.; Prettyman, Thomas H.

    2016-10-01

    We present a preliminary design for a neutron detection system that is compact, lightweight, and low power consuming, utilizing the CubeSat platform making it suitable for space-based applications. This is made possible using the scintillating crystal lithium indium diselenide (LiInSe26), the first crystal to include Li6 in the crystalline structure, and a silicon avalanche photodiode. The schematics of this instrument are presented as well as the response of the instrument to initial testing under alpha radiation. A principal aim of this work is to demonstrate the feasibility of such a neutron detection system within a CubeSat platform. The entire end-to-end system presented here is 10×10×15 cm3, weighs 670 g, and requires 5 V direct current at 3 W.

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

    PubMed

    Mazrou, H; Nedjar, A; Seguini, T

    2016-08-01

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

  2. Exploring the structure of biological macromolecules in solution using Quokka, the small angle neutron scattering instrument, at ANSTO

    NASA Astrophysics Data System (ADS)

    Wood, Kathleen; Jeffries, Cy M.; Knott, Robert B.; Sokolova, Anna; Jacques, David A.; Duff, Anthony P.

    2015-10-01

    Small angle neutron scattering (SANS) is widely used to extract structural parameters, shape and other types of information from a vast array of materials. The technique is applied to biological macromolecules and their complexes in solution to reveal information often not accessible by other techniques. SANS measurements on biomolecules present some particular challenges however, one of which is suitable instrumentation. This review details SANS experiments performed on two well-characterised globular proteins (lysozyme and glucose isomerase) using Quokka, the recently commissioned SANS instrument at the Australian Nuclear Science and Technology Organisation (ANSTO). The instrument configuration as well as data collection and reduction strategies for biological investigations are discussed and act as a general reference for structural biologists who use the instrument. Both model independent analysis of the two proteins and ab initio modelling illustrate that Quokka-SANS data can be used to successfully model the overall shapes of proteins in solution, providing a benchmark for users.

  3. Elemental analysis of Anethum gravedlens, Sismbrium Irio Linn and Veronia Anthelmintica seeds by instrumental neutron activation analysis.

    PubMed

    Fatima, I; Waheed, S; Zaidi, J H

    2013-01-01

    Instrumental neutron activation analysis has been used to characterize As, Ba, Br, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hg, K, Mn, Na, Rb, Sb, Se and Zn, and Sc in seeds of Anethum graveolens (Dill), Sisymbrium irio Linn. (Wild Mustard) and Vernonia anthelmintica (Iron Weed). Dill seed was found to contain high K while Wild Mustard has high Fe, Mn and Na levels. Iron Weed has highest Cl, Co, Cr and Zn content with least concentration of Fe.

  4. Instrumental activation analysis of coal and fly ash with thermal and epithermal neutrons and short-lived nuclides

    USGS Publications Warehouse

    Steinnes, E.; Rowe, J.J.

    1976-01-01

    Instrumental neutron activation analysis is applied to the determination of about 25 elements in coals and fly ash by means of nuclides with half-lives of less than 48 h ; thermal and epithermal irradiations are used. The results indicate that epithermal activation is preferable for twelve of the elements (Ga, As, Br, Sr, In, Cs, Ba, La, Sm, Ho, W and U). Data for SRM 1632 (coal) and SRM 1633 (fly ash) compare favorably with the results obtained by other investigators. ?? 1976.

  5. Comparing the Coronal Flaring Efficacy of Five Different Instruments Using Cone-Beam Computed Tomography

    PubMed Central

    Homayoon, Amin; Hamidi, Mahmood Reza; Haddadi, Azam; Madani, Zahra Sadat; Moudi, Ehsan; Bijani, Ali

    2015-01-01

    Introduction: Fearless removal of tooth structure during canal preparation and shaping has negative effects on the prognosis of treatment. On the other hand, sufficient pre-enlargement facilitates exact measurement of the apical size. The present in vitro study aimed to compare the efficacy of Gates-Glidden drills, K3, ProTaper, FlexMaster and RaCe instruments in dentin removal during coronal flaring using cone-beam computed tomography (CBCT). Methods and Materials: A total of 40 mandibular molars were selected and the coronal areas of their mesiobuccal and mesiolingual root canals were randomly prepared with either mentioned instruments. Pre- and post-instrumentation CBCT images were taken and the thickness of canal walls was measured in 1.5- and 3-mm distances from the furcation area. Data were analyzed using the one-way ANOVA. Tukey’s post hoc tests were used for two-by-two comparisons. Results: At 1.5-mm distance, there was no significant difference between different instruments. However, at 3-mm distances, Gates-Glidden drills removed significantly more dentin compared to FlexMaster files (mean=0.18 mm) (P<0.02); however, two-by-two comparisons did not reveal any significant differences between the other groups. Conclusion: All tested instruments can be effectively used in clinical settings for coronal pre-enlargement. PMID:26525955

  6. A Beam Scattering Instrument for the Dynamics Studies of Surface-Induced Dissociation Processes

    SciTech Connect

    Shukla, Anil K. ); Futrell, Jean H. )

    2003-01-01

    A new beam scattering instrument has been constructed to study the dynamics of ion-surface collisions, especially surface-induced dissociation of polyatomic ions. The instrument uses a bench top double focusing mass spectrometer as the source of a well-defined ion beam for transmission into a collision chamber. The primary ions are decelerated to desired ion energy (as low as 5 eV) by a series of tube lenses and collide the surface at 45 degrees. Thus, the ion energy for surface-induced dissociations can be varied from {approx}5 cV to >1 keV. The secondary ions are energy and mass analyzed by a cylindrical energy analyzer and quadrupole mass filter, respectively, and detected by a channel electron multiplier operating in pulse counting mode. The detector assembly can be rotated with respect to the collision center between the specular angle and surface parallel to measure intensity and energy distributions of scattered primary and fragment ions as a function of scattering angle. The newly constructed instrument has been tested for its performance and used to study the dissociation of ethanol molecular ions colliding with a self-assembled monolayer surface of fluorinated thiol on gold (111) crystal and first results are presented here.

  7. Modeled Martian subsurface elemental composition measurements with the Probing In situ with Neutron and Gamma ray instrument: Gamma and Neutron Measurements on Mars

    DOE PAGES

    Nowicki, Suzanne F.; Evans, Larry G.; Starr, Richard D.; ...

    2017-02-01

    Here, the Probing In situ with Neutrons and Gamma rays (PING) instrument is an innovative application of active neutron-induced gamma-ray technology. The objective of PING is to measure the elemental composition of the Martian regolith. As part 2 of a two-part submission, this manuscript presents PING's sensitivities as a function of the Martian regolith depth and PING's uncertainties in the measurements as a function of observation time in passive and active mode. Part 1 of our submission models the associated regolith types. The modeled sensitivities show that in PING's active mode, where both a Pulsed Neutron Generator (PNG) and amore » Gamma-Ray Spectrometer (GRS) are used, PING can interrogate the material below the rover to about 20 cm due to the penetrating nature of the high-energy neutrons and the resulting secondary gamma rays observed with the GRS. PING is capable of identifying most major and minor rock-forming elements, including H, O, Na, Mn, Mg, Al, Si, P, S, Cl, Cr, K, Ca, Ti, Fe and Th. The modeled uncertainties show that PING's use of a PNG reduces the required observation times by an order of magnitude over a passive operating mode where the PNG is turned off. While the active mode allows for more complete elemental inventories with higher sensitivity, the gamma-ray signatures of some elements are strong enough to detect in passive mode. We show that PING can detect changes in key marker elements and make thermal neutron measurements in about 1 minute that are sensitive to H and Cl.« less

  8. A quality assessment of the effects of a hydrogenous filter on a p(66)Be(40) neutron beam.

    PubMed

    Slabbert, J P; Binns, P J; Jones, H L; Hough, J H

    1989-11-01

    Recent measurements in a p(62)Be(36) neutron therapy beam have shown that the quality of the in-phantom beam changes with depth. This variation can be ascribed to the presence of a relatively large low-energy neutron component emanating from the neutron source. As part of the pre-clinical calibration programme at a newly commissioned neutron therapy facility, radiobiological and microdosimetric observations were made to determine the magnitude of this effect on a p(66)Be(40) beam and to evaluate the hardening effect of a hydrogenous filter. The reported data identify a correlation between the two assays and quantify a linear relationship between y* and filter thicknesses less than or equal to 6 cm. Using the data obtained in the study, a filter thickness was selected to comply with clinical requirements. By employing lineal energy spectra, it is demonstrated that subtle changes in beam quality may be quantified in a reproducible manner without resorting to time-consuming radiobiological studies.

  9. Relative measurements of fast neutron contamination in 18-MV photon beams from two linear accelerators and a betatron.

    PubMed

    Gur, D; Bukovitz, G; Rosen, J C; Holmes, B G

    1979-01-01

    Fast neutron contamination in photon beams in the 20 MV range have been reported in recent years. In order to determine if the variations were due mainly to differences in measurement procedures, or inherent in the design of the accelerators, three different 18-MV (BJR) photon beams were compared using identical analytical techniques. The units studied were a Philips SL/75-20 and a Siemens Mevatron-20 linear accelerators and a Schimadzu betatron. Gamma spectroscopy of an activated aluminum foil was the method used. By comparing the relative amounts of neutron contamination, errors associated with absolute measurements such as detector efficiency and differences in activation foils were eliminated. Fast neutron contaminations per rad of x rays in a ratio of 6.7:3.7:1 were found for the Philips, Schimadzu and Siemens accelerators, respectively.

  10. Using the in situ lift-out technique to prepare TEM specimens on a single-beam FIB instrument

    NASA Astrophysics Data System (ADS)

    Lekstrom, M.; McLachlan, M. A.; Husain, S.; McComb, D. W.; Shollock, B. A.

    2008-08-01

    Transmission electron microscope (TEM) specimens are today routinely prepared using focussed ion beam (FIB) instruments. Specifically, the lift-out method has become an increasingly popular technique and involves removing thin cross-sections from site-specific locations and transferring them to a TEM grid. This lift-out process can either be performed ex situ or in situ. The latter is mainly carried out on combined dual-beam FIB and scanning electron microscope (SEM) systems whereas conventional single-beam instruments often are limited to the traditional ex situ method. It is nevertheless desirable to enhance the capabilities of existing single-beam instruments to allow for in situ lift-out preparation to be performed since this technique offers a number of advantages over the older ex situ method. A single-beam FIB instrument was therefore modified to incorporate an in situ micromanipulator fitted with a tungsten needle, which can be attached to a cut-out FIB section using ion beam induced platinum deposition. This article addresses the issues of using an ion beam to monitor the in situ manipulation process as well as approaches that can be used to create stronger platinum welds between two objects, and finally, views on how to limit the extent of ion beam damage to the specimen surface.

  11. Neutron imaging of radioactive sources

    NASA Astrophysics Data System (ADS)

    Hameed, F.; Karimzadeh, S.; Zawisky, M.

    2008-08-01

    Isotopic neutron sources have been available for more than six decades. At the Atomic Institute in Vienna, operating a 250 kW TRIGA reactor, different neutron sources are in use for instrument calibration and fast neutron applications but we have only little information about their construction and densities. The knowledge of source design is essential for a complete MCNP5 modeling of the experiments. Neutron radiography (NR) and neutron tomography (NT) are the best choices for the non-destructive inspection of the source geometry and homogeneity. From the transmission analysis we gain information about the shielding components and the densities of the radio-isotopes in the cores. Three neutron sources, based on (alpha, n) reaction, have been investigated, two 239PuBe sources and one 241AmBe source. In the NR images the internal structure was clearly revealed using high-resolving scintillation and imaging plate detectors. In one source tablet a crack was detected which causes asymmetric neutron emission. The tomography inspection of strong absorbing materials is more challenging due to the low beam intensity of 1.3x105 n/cm2s at our NT instrument, and due to the beam hardening effect which requires an extension of reconstruction software. The tomographic inspection of a PuBe neutron source and appropriate measures for background and beam hardening correction are presented.

  12. Decay and In-Beam Studies of Neutron-Deficient Po and Ra Isotopes at JYFL

    NASA Astrophysics Data System (ADS)

    Leino, M.; Allatt, R. G.; Andreyev, A. N.; Cocks, J. F. C.; Dorvaux, O.; Enqvist, T.; Eskola, K.; Helariutta, K.; Huyse, M.; Jones, P. M.; Julin, R.; Juutinen, S.; Kankaanpaeae, H.; Keenan, A.; Kettunen, H.; Kuusiniemi, P.; Muikku, M.; Rahkila, P.; Savelius, A.; Trzaska, W. H.; Uusitalo, J.; van Duppen, P.

    1999-05-01

    An extensive program to study the production, decay properties, and nuclear structure of very neutron-deficient polonium and radium nuclei is underway at the Department of Physics, University of Jyvaeskylae, Finland (JYFL). The main tools used in these studies are the gas-filled recoil separator RITU and various germanium gamma-ray arrays. In the course of these studies, among others the following new isotopes have been produced: 204Ra, 203Ra, and 202Ra. Isomeric alpha decaying states have been discovered in 203Ra and 191Po. Fine structure in the decay of 192Po to the oblate and prolate band heads in 188Pb has been observed. In-beam gamma-ray spectra have been, for the first time, measured for 192Po, 206Ra, 208Ra, and 210Ra. Development of collectivity in nuclei in the Po-Ra region and the systematics of reduced alpha widths will be discussed.

  13. Fusion neutron generation computations in a stellarator-mirror hybrid with neutral beam injection

    SciTech Connect

    Moiseenko, V. E.; Agren, O.

    2012-06-19

    In the paper [Moiseenko V.E., Noack K., Agren O. 'Stellarator-mirror based fusion driven fission reactor' J Fusion Energy 29 (2010) 65.], a version of a fusion driven system (FDS), i.e. a sub-critical fast fission assembly with a fusion plasma neutron source, is proposed. The plasma part of the reactor is based on a stellarator with a small mirror part. Hot ions with high perpendicular energy are assumed to be trapped in the magnetic mirror part. The stellarator part which connects to the mirror part and provides confinement for the bulk (deuterium) plasma. In the magnetic well of the mirror part, fusion reactions occur from collisions between a of hot ion component (tritium) with cold background plasma ions. RF heating is one option to heat the tritium. A more conventional method to sustain the hot ions is neutral beam injection (NBI), which is here studied numerically for the above-mentioned hybrid scheme. For these studies, a new kinetic code, KNBIM, has been developed. The code takes into account Coulomb collisions between the hot ions and the background plasma. The geometry of the confining magnetic field is arbitrary for the code. It is accounted for via a numerical bounce averaging procedure. Along with the kinetic calculations the neutron generation intensity and its spatial distribution are computed.

  14. Fast three-dimensional nanoscale metrology in dual-beam FIB-SEM instrumentation.

    PubMed

    Repetto, Luca; Buzio, Renato; Denurchis, Carlo; Firpo, Giuseppe; Piano, Emanuele; Valbusa, Ugo

    2009-10-01

    A quantitative surface reconstruction technique has been developed for the geometric characterization of three-dimensional structures by using a combined focused ion beam-scanning electron microscopy (FIB-SEM) instrument. A regular pattern of lines is milled at normal incidence on the sample to be characterized and an image is acquired at a large tilt angle. By analyzing the pattern under the tilted view, a quantitative estimation of surface heights is obtained. The technique has been applied to a test sample and nanoscale resolution has been achieved. The reported results are validated by a comparison with atomic force microscopy measurements.

  15. RECENT BEAM MEASUREMENTS AND NEW INSTRUMENTATION AT THE ADVANCED LIGHT SOURCE

    SciTech Connect

    Sannibale, Fernando; Baptiste, Kenneth; Barry, Walter; Chin, Michael; Filippetto, Daniele; Jaegerhofer, Lukas; Julian, James; Kwiatkowski, Slawomir; Low, Raymond; Plate, David; Portmann, Gregory; Robin, David; Scarvie, Tomas; Stupakov, Gennady; Weber, Jonah; Zolotorev, Max

    2008-05-05

    The Advanced Light Source (ALS) in Berkeley was the first of the soft x-ray third generation light source ever built, and since 1993 has been in continuous and successful operation serving a large community of users in the VUV and soft x-ray community. During these years the storage ring underwent through several important upgrades that allowed maintaining the performance of this veteran facility at the forefront. The ALS beam diagnostics and instrumentation have followed a similar path of innovation and upgrade and nowadays include most of the modem and last generation devices and technologies that are commercially available and used in the recently constructed third generation light sources. In this paper we will not focus on such already widely known systems, but we will concentrate our effort in the description of some measurements techniques, instrumentation and diagnostic systems specifically developed at the ALS and used during the last few years.

  16. Recent Beam Measurements and New Instrumentation at the Advanced Light Source

    SciTech Connect

    Sannibale, F.; Baptiste, K.; Barry, W.; Chin, M.; Filippetto, D.; Jaegerhofer, L.; Julian, J.; Kwiatkowski, S.; Low, R.; Plate, D.; Portmann, G.; Robin, D.; Scarvie, T.; Stupakov, G.; Weber, J.; Zolotorev, M.; /LBL, Berkeley

    2012-04-11

    The Advanced Light Source (ALS) in Berkeley was the first of the soft x-ray third generation light source ever built, and since 1993 has been in continuous and successful operation serving a large community of users in the VUV and soft x-ray community. During these years the storage ring underwent through several important upgrades that allowed maintaining the performance of this veteran facility at the forefront. The ALS beam diagnostics and instrumentation have followed a similar path of innovation and upgrade and nowadays include most of the modem and last generation devices and technologies that are commercially available and used in the recently constructed third generation light sources. In this paper we will not focus on such already widely known systems, but we will concentrate our effort in the description of some measurements techniques, instrumentation and diagnostic systems specifically developed at the ALS and used during the last few years.

  17. Off-axis dose equivalent due to secondary neutrons from uniform scanning proton beams during proton radiotherapy.

    PubMed

    Islam, M R; Collums, T L; Zheng, Y; Monson, J; Benton, E R

    2013-11-21

    The production of secondary neutrons is an undesirable byproduct of proton therapy and it is important to quantify the contribution from secondary neutrons to patient dose received outside the treatment volume. The purpose of this study is to investigate the off-axis dose equivalent from secondary neutrons experimentally using CR-39 plastic nuclear track detectors (PNTD) at ProCure Proton Therapy Center, Oklahoma City, OK. In this experiment, we placed several layers of CR-39 PNTD laterally outside the treatment volume inside a phantom and in air at various depths and angles with respect to the primary beam axis. Three different proton beams with max energies of 78, 162 and 226 MeV and 4 cm modulation width, a 5 cm diameter brass aperture, and a small snout located 38 cm from isocenter were used for the entire experiment. Monte Carlo simulations were also performed based on the experimental setup using a simplified snout configuration and the FLUKA Monte Carlo radiation transport code. The measured ratio of secondary neutron dose equivalent to therapeutic primary proton dose (H/D) ranged from 0.3 ± 0.08 mSv Gy−1 for 78 MeV proton beam to 37.4 ± 2.42 mSv Gy−1 for 226 MeV proton beam. Both experiment and simulation showed a similar decreasing trend in dose equivalent with distance to the central axis and the magnitude varied by a factor of about 2 in most locations. H/D was found to increase as the energy of the primary proton beam increased and higher H/D was observed at 135° compared to 45° and 90°. The overall higher H/D in air indicates the predominance of external neutrons produced in the nozzle rather than inside the body.

  18. A system of materials composition and geometry arrangement for fast neutron beam thermalization: An MCNP study

    NASA Astrophysics Data System (ADS)

    Uhlář, Radim; Alexa, Petr; Pištora, Jaromír

    2013-03-01

    Compact deuterium-tritium neutron generators emit fast neutrons (14.2 MeV) that have to be thermalized for neutron activation analysis experiments. To maximize thermal neutron flux and minimize epithermal and fast neutron fluxes across the output surface of the neutron generator facility, Monte Carlo calculations (MCNP5; Los Alamos National Laboratory) for different moderator types and widths and collimator and reflector designs have been performed. A thin lead layer close to the neutron generator as neutron multiplier followed by polyethylene moderator and surrounded by a massive lead and nickel collimator and reflector was obtained as the optimum setup.

  19. 235U Determination using In-Beam Delayed Neutron Counting Technique at the NRU Reactor

    SciTech Connect

    Andrews, M. T.; Bentoumi, G.; Corcoran, E. C.; Dimayuga, I.; Kelly, D. G.; Li, L.; Sur, B.; Rogge, R. B.

    2015-11-17

    This paper describes a collaborative effort that saw the Royal Military College of Canada (RMC)’s delayed neutron and gamma counting apparatus transported to Canadian Nuclear Laboratories (CNL) for use in the neutron beamline at the National Research Universal (NRU) reactor. Samples containing mg quantities of fissile material were re-interrogated, and their delayed neutron emissions measured. This collaboration offers significant advantages to previous delayed neutron research at both CNL and RMC. This paper details the determination of 235U content in enriched uranium via the assay of in-beam delayed neutron magnitudes and temporal behavior. 235U mass was determined with an average absolute error of ± 2.7 %. This error is lower than that obtained at RMCC for the assay of 235U content in aqueous solutions (3.6 %) using delayed neutron counting. Delayed neutron counting has been demonstrated to be a rapid, accurate, and precise method for special nuclear material detection and identification.

  20. Combined reactor neutron beam and {sup 60}Co γ-ray radiation effects on CMOS APS image sensors

    SciTech Connect

    Wang, Zujun Chen, Wei; Sheng, Jiangkun; Liu, Yan; Xiao, Zhigang; Huang, Shaoyan; Liu, Minbo

    2015-02-15

    The combined reactor neutron beam and {sup 60}Co γ-ray radiation effects on complementary metal-oxide semiconductor (CMOS) active pixel sensors (APS) have been discussed and some new experimental phenomena are presented. The samples are manufactured in the standard 0.35-μm CMOS technology. Two samples were first exposed to {sup 60}Co γ-rays up to the total ionizing dose (TID) level of 200 krad(Si) at the dose rates of 50.0 and 0.2 rad(Si)/s, and then exposed to neutron fluence up to 1 × 10{sup 11} n/cm{sup 2} (1-MeV equivalent neutron fluence). One sample was first exposed to neutron fluence up to 1 × 10{sup 11} n/cm{sup 2} (1-MeV equivalent neutron fluence), and then exposed to {sup 60}Co γ-rays up to the TID level of 200 krad(Si) at the dose rate of 0.2 rad(Si)/s. The mean dark signal (K{sub D}), the dark signal non-uniformity (DSNU), and the noise (V{sub N}) versus the total dose and neutron fluence has been investigated. The degradation mechanisms of CMOS APS image sensors have been analyzed, especially for the interaction induced by neutron displacement damage and TID damage.

  1. An optional focusing SELENE extension to conventional neutron guides: A case study for the ESS instrument BIFROST

    NASA Astrophysics Data System (ADS)

    Hansen, U. B.; Bertelsen, M.; Stahn, J.; Lefmann, K.

    2017-04-01

    The high brilliance at the European Spallation Source (ESS) will allow for performing experiments with much smaller samples than at present neutron facilities and in much more complex sample environments. However the higher flux also results in higher background from unwanted neutrons not originating from scattering of the sample. We here present a new design idea for beam delivery, where a 165 m ballistic guide system with good transport properties is followed by a 4-8 m SELENE guide system similar to Montel optics used for X-ray optics. We have investigated the system by detailed Monte-Carlo simulations using McStas. We show that under certain conditions, this set-up works surprisingly well, with a brilliance transfer of 20-60% for neutrons of wavelength 4 Å and above. We demonstrate that the guide system is able to focus the beam almost perfectly onto samples sizes in the range of 0.1-2 mm. We furthermore show that our SELENE system is insensitive to gravity and to realistic values of guide waviness. We argue that this guide system can be useful as an optional guide insert when small samples are used in the vicinity of bulky sample environment, e.g. for high-field or high-pressure experiments.

  2. Detection of Procedural Errors during Root Canal Instrumentation using Cone Beam Computed Tomography

    PubMed Central

    Guedes, Orlando Aguirre; da Costa, Marcus Vinícius Corrêa; Dorilêo, Maura Cristiane Gonçales Orçati; de Oliveira, Helder Fernandes; Pedro, Fábio Luis Miranda; Bandeca, Matheus Coelho; Borges, Álvaro Henrique

    2015-01-01

    Background: This study investigated procedural errors made during root canal preparation with nickel-titanium (NiTi) instruments, using cone beam computed tomography (CBCT) imaging method. Materials and Methods: A total of 100 human mandibular molars were divided into five groups (n = 20) according to the NiTi system used for root canal preparation: Group 1 - BioRaCe, Group 2 - K3, Group 3 - ProTaper, Group 4 - Mtwo and Group 5 - Hero Shaper. CBCT images were obtained to detect procedural errors made during root canal preparation. Two examiners evaluated the presence or absence of fractured instruments, perforations, and canal transportations. Chi-square test was used for statistical analyzes. The significance level was set at a=5%. Results: In a total of 300 prepared root canals, 43 (14.33%) procedural errors were detected. Perforation was the procedural errors most commonly observed (58.14%). Most of the procedural errors were observed in the mesiobuccal root canal (48.84%). In the analysis of procedural errors, there was a significant difference (P < 0.05) between the groups of NiTi instruments. The root canals instrumented with BioRaCe had significantly less procedural errors. Conclusions: CBCT permitted the detection of procedural errors during root canal preparation. The frequency of procedural errors was low when root canals preparation was accomplished with BioRaCe system. PMID:25878475

  3. Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development

    SciTech Connect

    Gilpatrick, John D.; Batygin, Yuri K.; Gonzales, Fermin; Gruchalla, Michael E.; Kutac, Vincent G.; Martinez, Derwin; Sedillo, James Daniel; Pillai, Chandra; Rodriguez Esparza, Sergio; Smith, Brian G.

    2012-05-15

    The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H{sup -} beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

  4. Comparison of the performance of different instruments in the stray neutron field around the CERN Proton Synchrotron.

    PubMed

    Aza, Eleni; Caresana, Marco; Cassell, Christopher; Colombo, Valeria; Damjanovic, Sanja; Gilardoni, Simone; Manessi, Giacomo Paolo; Pangallo, Michel; Perrin, Daniel; Silari, Marco

    2014-10-01

    This paper discusses an intercomparison campaign carried out in several locations around the CERN Proton Synchrotron. The locations were selected in order to perform the measurements in different stray field conditions. Various neutron detectors were employed: ionisation chambers, conventional and extended range rem counters, both commercial and prototype ones, including a novel instrument called LUPIN, specifically conceived to work in pulsed fields. The attention was focused on the potential differences in the instrument readings due to dead-time losses that are expected to affect most commercial units. The results show that the ionisation chambers and LUPIN agree well with the expected H*(10) values, as derived from FLUKA simulations, showing no relevant underestimations even in strongly pulsed fields. On the contrary, the dead-time losses of the other rem counters induced an underestimation in pulsed fields that was more important for instruments characterised by a higher dead time.

  5. 26Si excited states via one-neutron removal from a 27Si radioactive ion beam

    NASA Astrophysics Data System (ADS)

    Chen, J.; Chen, A. A.; Amthor, A. M.; Bazin, D.; Becerril, A. D.; Gade, A.; Galaviz, D.; Glasmacher, T.; Kahl, D.; Lorusso, G.; Matos, M.; Ouellet, C. V.; Pereira, J.; Schatz, H.; Smith, K.; Wales, B.; Weisshaar, D.; Zegers, R. G. T.

    2012-04-01

    A study of 26Si states by neutron removal from a fast radioactive beam of 27Si has been performed. A beam of 27Si of energy 84.3 MeV/nucleon impinged on a polypropylene foil (C3H6) of 180 mg/cm2 thickness. Deexcitation γ rays were detected with a highly segmented germanium detector array, in coincidence with the 26Si recoils, and the corresponding 26Si level energies were determined. In comparing our results to two previous γ-ray spectroscopic studies of 26Si level structures, we find good agreement with a recent measurement of the 12C(16O,2nγ)26Si reaction. Our results support the use of excitation energies from that study in helping determine the important resonance energies for the thermonuclear 25Al(p,γ)26Si reaction rate. We do not observe a bound state at 4093 keV reported in an earlier study of the 24Mg(3He,nγ)26Si reaction.

  6. The NIST NBSR and Cold Neutron Research Facility

    SciTech Connect

    Rush, J.J.

    1994-12-31

    The 20 MW Neutron Beam Split-Core Reactor (NBSR) has nine radial thermal beam tubes, and a large, highly accessible (35cm) cold source serving an extensive network of eight guide tubes. In operation or under construction are twenty-five neutron beam instruments (20 for neutron scattering) and about a dozen other facilities for neutron trace analysis, dosimetry and irradiation. The 6 x 15cm cold neutron guides are coated with {sup 58}Ni, and the last three being installed this fall are coated top and bottom with supermirrors for further increases in intensity. The new semi-spherical liquid hydrogen source will be described, along with the eight scattering instruments (reflectometry, SANS and high-resolution spectroscopy) which have, or will have, an extensive use in biological research. These instruments will likely provide the best overall capability in the U.S. for the next decade for a number of applications in biomolecular structure and dynamics.

  7. Active Interrogation of Sensitive Nuclear Material Using Laser Driven Neutron Beams

    SciTech Connect

    Favalli, Andrea; Roth, Markus

    2015-05-01

    An investigation of the viability of a laser-driven neutron source for active interrogation is reported. The need is for a fast, movable, operationally safe neutron source which is energy tunable and has high-intensity, directional neutron production. Reasons for the choice of neutrons and lasers are set forth. Results from the interrogation of an enriched U sample are shown.

  8. Development of an inner profile measurement instrument using a ring beam device

    NASA Astrophysics Data System (ADS)

    Yoshizawa, T.; Wakayama, T.

    2010-11-01

    Inner profile measurement is an important matter in such fields as medicine, dentistry and anthropology as well as mechanical engineering and other industrial applications. Here we describe recent development of our measurement principle for inner diameter of pipes and/or holes. The key device in this technique is a ring beam device which consists of a conical mirror and a laser diode. And the fundamental principle is based on optical sectioning without using any contact type stylus. The optically sectioned profile of an inner wall of a pipe-like object is analyzed to give the inner profile in addition to the inner diameter. This optical instrument with a simple and small configuration is now under development for practical uses. In our hitherto trial experimental works, the availability of this instrument has been evaluated in many cases and availability for practical applications is expected, especially, for measurement and inspection of mechanical components and elements besides pipes. This ring beam device consisting of a conical mirror and a LD is assembled to form a disk-like light sheet. We show measurement result of pipes and holes, and, at the same time, report a compact inner profile measuring instrument at this point. Both the ring beam device and a miniaturized CCD camera are fabricated into a glass tube. Availability of this instrument is shown by measuring the inner profiles of various pipes. In response to this trial, there appeared a strong request that not only the internal but external profiles should be measured simultaneously. Therefore we propose potentially possible method for measurement of external profile at the same time with internal profile. If one pair of concave mirrors are used in our arrangement, external profile is captured. In combination with inner profile measurement technique, simultaneous measurement of inner and outer profiles becomes attainable. A measurement result on a bevel gear shows availability of here proposed

  9. Planck 2015 results. VII. High Frequency Instrument data processing: Time-ordered information and beams

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Adam, R.; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bertincourt, B.; Bielewicz, P.; Bock, J. J.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Le Jeune, M.; Leahy, J. P.; Lellouch, E.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Moreno, R.; Morgante, G.; Mortlock, D.; Moss, A.; Mottet, S.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sandri, M.; Santos, D.; Sauvé, A.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vibert, L.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Watson, R.; Wehus, I. K.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-09-01

    The Planck High Frequency Instrument (HFI) has observed the full sky at six frequencies (100, 143, 217, 353, 545, and 857 GHz) in intensity and at four frequencies in linear polarization (100, 143, 217, and 353 GHz). In order to obtain sky maps, the time-ordered information (TOI) containing the detector and pointing samples must be processed and the angular response must be assessed. The full mission TOI is included in the Planck 2015 release. This paper describes the HFI TOI and beam processing for the 2015 release. HFI calibration and map making are described in a companion paper. The main pipeline has been modified since the last release (2013 nominal mission in intensity only), by including a correction for the nonlinearity of the warm readout and by improving the model of the bolometer time response. The beam processing is an essential tool that derives the angular response used in all the Planck science papers and we report an improvement in the effective beam window function uncertainty of more than a factor of 10 relative to the2013 release. Noise correlations introduced by pipeline filtering function are assessed using dedicated simulations. Angular cross-power spectra using data sets that are decorrelated in time are immune to the main systematic effects.

  10. Observation of Very High Passive Mode Thermal Neutron Counts by the MSL DAN Instrument at Marias Pass in Gale Crater

    NASA Astrophysics Data System (ADS)

    Jun, I.; Mitrofanov, I. G.; Litvak, M. L.; Sanin, A. B.; Martinez Sierra, L. M.; Frydenvang, J.; Fedosov, F.; Golovin, D.; Hardgrove, C. J.; Harshman, K.; Kozyrev, A.; Malakhov, A. V.; Mischna, M. A.; Moersch, J.; Mokrousov, M.; Nikiforov, S.; Tate, C. G.

    2015-12-01

    Since landing in August 2012, DAN has provided a wealth of scientific data from the successful surface operation in both Active mode and Passive mode. The main scientific objectives of DAN are twofold. The primary objective is to measure the bulk hydrogen abundance (in forms of water or hydrated minerals) of the subsurface. The secondary objective is to measure the background neutron environment at the surface. DAN achieves the first objective by using the pulsed neutron generator (PNG) as a pulsed 14 MeV neutron source (active mode). When no neutron pulse is used (passive mode), DAN measures the neutron background environment at the Martian surface. The DAN active data have extensively and successfully used in estimating the near-surface contents of hydrogen (in terms of "water equivalent hydrogen" or WEH) and chlorine (in terms of "absorption equivalent chlorine" or AEC) at multiple locations in Gale crater. In the mean time, DAN has been accumulating the passive mode data in almost all sols since landing, and it is the main topic of this presentation. Particularly, we want to show the DAN data on Sol 991 and 992 where we observed very high passive thermal neutron count - a factor of ~2 higher than usual count. As a reminder, note that many different factors would influence the amplitude of DAN passive thermal neutron counts - GCR condition, soil compositions, water/chlorine contents, etc. The Sol 991/992 location, which is at a region near a rock target called Elk in Marias Pass, was also analyzed by another MSL instrument ChemCAM. And interestingly, its data show that the Elk target is estimated to contain as high as 80 wt% of SiO2, which is radically different from what we have used as a reference soil composition for the interpretation of the DAN passive data. This means that the DAN passive data simulations have to be revisited to account for different soil composition data at the Elk target region. In the final presentation, we will present new simulation

  11. A Monte Carlo model system for core analysis and epithermal neutron beam design at the Washington State University Radiation Center

    SciTech Connect

    Burns, T.D. Jr.

    1996-05-01

    The Monte Carlo Model System (MCMS) for the Washington State University (WSU) Radiation Center provides a means through which core criticality and power distributions can be calculated, as well as providing a method for neutron and photon transport necessary for BNCT epithermal neutron beam design. The computational code used in this Model System is MCNP4A. The geometric capability of this Monte Carlo code allows the WSU system to be modeled very accurately. A working knowledge of the MCNP4A neutron transport code increases the flexibility of the Model System and is recommended, however, the eigenvalue/power density problems can be run with little direct knowledge of MCNP4A. Neutron and photon particle transport require more experience with the MCNP4A code. The Model System consists of two coupled subsystems; the Core Analysis and Source Plane Generator Model (CASP), and the BeamPort Shell Particle Transport Model (BSPT). The CASP Model incorporates the S({alpha}, {beta}) thermal treatment, and is run as a criticality problem yielding, the system eigenvalue (k{sub eff}), the core power distribution, and an implicit surface source for subsequent particle transport in the BSPT Model. The BSPT Model uses the source plane generated by a CASP run to transport particles through the thermal column beamport. The user can create filter arrangements in the beamport and then calculate characteristics necessary for assessing the BNCT potential of the given filter want. Examples of the characteristics to be calculated are: neutron fluxes, neutron currents, fast neutron KERMAs and gamma KERMAs. The MCMS is a useful tool for the WSU system. Those unfamiliar with the MCNP4A code can use the MCMS transparently for core analysis, while more experienced users will find the particle transport capabilities very powerful for BNCT filter design.

  12. Production of neutron-rich Ca, Sn, and Xe isotopes in transfer-type reactions with radioactive beams

    SciTech Connect

    Adamian, G. G.; Antonenko, N. V.; Lacroix, D.

    2010-12-15

    The production cross sections of neutron-rich isotopes {sup 52,54,56,58,60}Ca, {sup 136,138,140,142}Sn, and {sup 146,148,150,152}Xe are predicted for future experiments in the diffusive multinucleon transfer reactions {sup 86,90,92,94}Kr, {sup 124,130,132,134}Sn, {sup 136,140,142,146}Xe, and {sup 138,144,146}Ba+{sup 48}Ca with stable and radioactive beams at incident energies close to the Coulomb barrier. Because of the small cross sections, the production of neutron-rich isotopes requires the optimal choice of projectile-target combinations and bombarding energies.

  13. (30)Si mole fraction of a silicon material highly enriched in (28)Si determined by instrumental neutron activation analysis.

    PubMed

    D'Agostino, Giancarlo; Di Luzio, Marco; Mana, Giovanni; Oddone, Massimo; Pramann, Axel; Prata, Michele

    2015-06-02

    The latest determination of the Avogadro constant, carried out by counting the atoms in a pure silicon crystal highly enriched in (28)Si, reached the target 2 × 10(-8) relative uncertainty required for the redefinition of the kilogram based on the Planck constant. The knowledge of the isotopic composition of the enriched silicon material is central; it is measured by isotope dilution mass spectrometry. In this work, an independent estimate of the (30)Si mole fraction was obtained by applying a relative measurement protocol based on Instrumental Neutron Activation Analysis. The amount of (30)Si isotope was determined by counting the 1266.1 keV γ-photons emitted during the radioactive decay of the radioisotope (31)Si produced via the neutron capture reaction (30)Si(n,γ)(31)Si. The x((30)Si) = 1.043(19) × 10(-6) mol mol(-1) is consistent with the value currently adopted by the International Avogadro Coordination.

  14. Development of instrumentation for imaging scattered cold neutrons. Phase 1 report

    SciTech Connect

    Walter, J.

    1988-01-01

    The project involves the development of a cold neutron imaging array consisting of a neutron to charged particle convertor and an array of Si detector pixels. Each detector pixel has its own preamplifier/signal conditioning chain and its own data storage registers. The parallel processing capability will be contained on WSI-ASIC sub-array wafers with 196 channels per wafer. Such sub-arrays can be assembled into large focal plane arrays. The high speed of the silicon detectors and signal conditioning chains makes 100,000 cps per pixel a realistic goal. Calculations and experimental measurements of neutron detection efficiency as a function of neutron wavelength are very encouraging. Preliminary design studies of the preamplifier/signal conditioning chain appear to present no insurmountable technical problems.

  15. 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.

  16. Chromosomal aberrations in peripheral blood lymphocytes exposed to a mixed beam of low energy neutrons and gamma radiation.

    PubMed

    Wojcik, A; Obe, G; Lisowska, H; Czub, J; Nievaart, V; Moss, R; Huiskamp, R; Sauerwein, W

    2012-09-01

    Cells exposed to thermal neutrons are simultaneously damaged by radiations with high and low linear energy transfer (LET). A question relevant for the assessment of risk of exposure to a mixed beam is whether the biological effect of both radiation types is additive or synergistic. The aim of the present investigation was to calculate whether the high and low LET components of a thermal neutron field interact when damaging cells. Human peripheral blood lymphocytes were exposed to neutrons from the HB11 beam at the Institute for Energy and Transport, Petten, Netherlands, in a 37 °C water phantom at varying depths, where the mix of high and low LET beam components differs. Chromosomal aberrations were analysed and the relative biological effectiveness (RBE) values as well as the expected contributions of protons and photons to the aberration yield were calculated based on a dose response of aberrations in lymphocytes exposed to (60)Co gamma radiation. The RBE for 10 dicentrics per 100 cells was 3 for mixed beam and 7.2 for protons. For 20 dicentrics per 100 cells the respective values were 2.4 and 5.8. Within the limitations of the experimental setup the results indicate that for this endpoint there is no synergism between the high and low LET radiations.

  17. In situ neutron spectroscopy on the martian surface: modeling the hydra instrument for different mission scenarios

    SciTech Connect

    Lawrence, David J. ,; Elphic, R. C.; Feldman, W. C.; Moore, K. R.; Prettyman, T. H.; Weins, R. C.

    2003-01-01

    Neutron spectroscopy has proven to be highly successful in remotely detecting and measuring the abundance of water on planetary surfaces such as Mars and the Moon. Because of the central role played by water on Mars and the need to make in situ measurements of water abundances for landed missions, neutron spectroscopy is being investigated as a technique for quickly determining the near-surface water abundance for fhture Mars missions, such as the Mars Smart Larider (MSL).

  18. Novel multi-telescopes beam combiners for next generation instruments (FIRST/SUBARU)

    NASA Astrophysics Data System (ADS)

    Martin, G.; Pugnat, T.; Gardillou, F.; Cassagnettes, C.; Barbier, D.; Guyot, C.; Hauden, J.; Huby, E.; Lacour, S.

    2016-07-01

    Integrated optic devices are nowadays achieving extremely good performances in the field of astronomical interferometry, as shown by PIONIER or GRAVITY silica/silicon-based instruments, already installed at VLTI. In order to address other wavelengths, increase the number of apertures to be combined and eventually ensure on-chip phase modulation, we are working on a novel generation of beam combiners, based on the hybridization of glass waveguides, that can ensure very sharp bend radius, high confinement and low propagation losses, together with lithium niobate phase modulators and channel waveguides that can achieve on-chip, fast (<100kHz) phase modulation. The work presented here has been realized in collaboration with our technological partners TeemPhotonics for glass waveguides and iXBlue-PSD for lithium niobate phase modulators. We will present our results on a hybrid glass/niobate (passive/active) beam combiner that has been developed in the context of FIRST/SUBARU 9T beam combiner. The combiner is structured in three parts: a) the first stage (passive glass) achieves beam splitting from one input to eight outputs, and that for nine input fibers coming from the sub-apertures of the Subaru telescope; b) the second stage consists on a 72 channel waveguides lithium niobate phase modulator in a push-pull configuration that allows to modify on-chip the relative phase between the 36 pairs of waveguides; c) a final recombination system of Y-junctions (passive glass) that allows to obtain combination of each input to every other one. The aim of this presentation is to discuss different issues of the combiners, such as transmission, birefringence, half-wave voltage modulation and spectral range.

  19. Dynamic imaging with a triggered and intensified CCD camera system in a high-intensity neutron beam

    NASA Astrophysics Data System (ADS)

    Vontobel, P.; Frei, G.; Brunner, J.; Gildemeister, A. E.; Engelhardt, M.

    2005-04-01

    When time-dependent processes within metallic structures should be inspected and visualized, neutrons are well suited due to their high penetration through Al, Ag, Ti or even steel. Then it becomes possible to inspect the propagation, distribution and evaporation of organic liquids as lubricants, fuel or water. The principle set-up of a suited real-time system was implemented and tested at the radiography facility NEUTRA of PSI. The highest beam intensity there is 2×107 cm s, which enables to observe sequences in a reasonable time and quality. The heart of the detection system is the MCP intensified CCD camera PI-Max with a Peltier cooled chip (1300×1340 pixels). The intensifier was used for both gating and image enhancement, where as the information was accumulated over many single frames on the chip before readout. Although, a 16-bit dynamic range is advertised by the camera manufacturers, it must be less due to the inherent noise level from the intensifier. The obtained result should be seen as the starting point to go ahead to fit the different requirements of car producers in respect to fuel injection, lubricant distribution, mechanical stability and operation control. Similar inspections will be possible for all devices with repetitive operation principle. Here, we report about two measurements dealing with the lubricant distribution in a running motorcycle motor turning at 1200 rpm. We were monitoring the periodic stationary movements of piston, valves and camshaft with a micro-channel plate intensified CCD camera system (PI-Max 1300RB, Princeton Instruments) triggered at exactly chosen time points.

  20. Modeled Martian subsurface elemental composition measurements with the probing in situ with neutrons and gamma-ray (PING) instrument

    SciTech Connect

    Nowicki, Suzanne F.; Evans, Larry G.; Starr, Richard D.; Schweitzer, Jeffrey S.; Karunatillake, Suniti; McClanahan, Timothy P.; Moersch, Jeffrey E.; Parsons, Ann M.; Tate, Christopher G.

    2016-11-24

    Here, the Probing In situ with Neutrons and Gamma rays (PING) instrument is an innovative application of active neutron-induced gamma-ray technology. The objective of PING is to measure the elemental composition of the Martian regolith. As part 2 of a two-part submission, this manuscript presents PING's sensitivities as a function of the Martian regolith depth and PING's uncertainties in the measurements as a function of observation time in passive and active mode. Part 1 of our submission models the associated regolith types. The modeled sensitivities show that in PING's active mode, where both a Pulsed Neutron Generator (PNG) and a Gamma-Ray Spectrometer (GRS) are used, PING can interrogate the material below the rover to about 20 cm due to the penetrating nature of the high-energy neutrons and the resulting secondary gamma rays observed with the GRS. PING is capable of identifying most major and minor rock-forming elements, including H, O, Na, Mn, Mg, Al, Si, P, S, Cl, Cr, K, Ca, Ti, Fe and Th. The modeled uncertainties show that PING's use of a PNG reduces the required observation times by an order of magnitude over a passive operating mode where the PNG is turned off. While the active mode allows for more complete elemental inventories with higher sensitivity, the gamma-ray signatures of some elements are strong enough to detect in passive mode. We show that PING can detect changes in key marker elements and make thermal neutron measurements in about 1 minute that are sensitive to H and Cl.

  1. Modeled Martian subsurface elemental composition measurements with the probing in situ with neutrons and gamma-ray (PING) instrument

    DOE PAGES

    Nowicki, Suzanne F.; Evans, Larry G.; Starr, Richard D.; ...

    2016-11-24

    Here, the Probing In situ with Neutrons and Gamma rays (PING) instrument is an innovative application of active neutron-induced gamma-ray technology. The objective of PING is to measure the elemental composition of the Martian regolith. As part 2 of a two-part submission, this manuscript presents PING's sensitivities as a function of the Martian regolith depth and PING's uncertainties in the measurements as a function of observation time in passive and active mode. Part 1 of our submission models the associated regolith types. The modeled sensitivities show that in PING's active mode, where both a Pulsed Neutron Generator (PNG) and amore » Gamma-Ray Spectrometer (GRS) are used, PING can interrogate the material below the rover to about 20 cm due to the penetrating nature of the high-energy neutrons and the resulting secondary gamma rays observed with the GRS. PING is capable of identifying most major and minor rock-forming elements, including H, O, Na, Mn, Mg, Al, Si, P, S, Cl, Cr, K, Ca, Ti, Fe and Th. The modeled uncertainties show that PING's use of a PNG reduces the required observation times by an order of magnitude over a passive operating mode where the PNG is turned off. While the active mode allows for more complete elemental inventories with higher sensitivity, the gamma-ray signatures of some elements are strong enough to detect in passive mode. We show that PING can detect changes in key marker elements and make thermal neutron measurements in about 1 minute that are sensitive to H and Cl.« less

  2. Application of instrumental neutron activation and X-ray fluorescence analysis to the examination of objects of art

    NASA Astrophysics Data System (ADS)

    Panczyk, E.; Ligeza, M.; Walis, L.

    1999-01-01

    In the Institute of Nuclear Chemistry and Technology in Warsaw in collaboration with the Department of Preservation and Restoration of Works of Art of the Academy of Fine Arts in Cracow and National Museum in Warsaw systematic studies using nuclear methods, particulary instrumental neutron activation analysis and X-ray fluorescence analysis, have been carried out on the panel paintings from the Krakowska- Nowosadecka School and Silesian School of the period from the XIV-XVII century, Chinese and Thai porcelains and mummies fillings of Egyptian sarcophagi. These studies will provide new data to the existing data base, will permit to compare materials used by various schools and individual artists.

  3. Instruments to study fast neutrons fluxes in the upper atmosphere with the use of high-altitude balloons

    NASA Astrophysics Data System (ADS)

    Iyudin, A. F.; Bogomolov, V. V.; Galkin, V. I.; Golovanov, I. A.; Krasnov, A.; Markelova, A. K.; Markelov, I.; Morgunova, Yu.; Osedlo, V. I.; Panasyuk, M. I.; Rozhkov, G.; Svertilov, S. I.

    2015-11-01

    The successful circumpolar flight of the X-ray polarimeter PoGOLite in the northern hemisphere during the summer campaign of 2013 inspired us, the team consisting mostly of students and senior researchers, to develop a Modular Monitor of the Cosmic Neutral Emission (MMCNE) prototype that can be flown on the high-altitude balloons to study two components of neutral emission, namely spectra of neutrons and of gamma-rays in the upper layers of Earth atmosphere. Instrument modular concept, and some of the simulated detection characteristics for the selected layout will be presented in this paper.

  4. Stripping of H- beams by residual gas in the linac at the Los Alamos neutron science center

    SciTech Connect

    Mccrady, Rodney C; Ito, Takeyasu; Cooper, Martin D; Alexander, Saunders

    2010-09-07

    The linear accelerator at the Los Alamos Neutron Science Center (LANSCE) accelerates both protons and H{sup -} ions using Cockroft-Walton-type injectors, a drift-tube linac and a coupled-cavity linac. The vacuum is maintained in the range of 10{sup -6} to 10{sup -7} Torr; the residual gas in the vacuum system results in some stripping of the electrons from the H{sup -} ions resulting in beam spill and the potential for unwanted proton beams delivered to experiments. We have measured the amount of fully-stripped H{sup -} beam (protons) that end up at approximately 800 MeV in the beam switchyard at LANSCE using image plates as very sensitive detectors. We present here the motivation for the measurement, the measurement technique and results.

  5. Concept of a novel fast neutron imaging detector based on THGEM for fan-beam tomography applications

    NASA Astrophysics Data System (ADS)

    Cortesi, M.; Zboray, R.; Adams, R.; Dangendorf, V.; Prasser, H.-M.

    2012-02-01

    The conceptual design and operational principle of a novel high-efficiency, fast neutron imaging detector based on THGEM, intended for future fan-beam transmission tomography applications, is described. We report on a feasibility study based on theoretical modeling and computer simulations of a possible detector configuration prototype. In particular we discuss results regarding the optimization of detector geometry, estimation of its general performance, and expected imaging quality: it has been estimated that detection efficiency of around 5-8% can be achieved for 2.5 MeV neutrons; spatial resolution is around one millimeter with no substantial degradation due to scattering effects. The foreseen applications of the imaging system are neutron tomography in non-destructive testing for the nuclear energy industry, including examination of spent nuclear fuel bundles, detection of explosives or drugs, as well as investigation of thermal hydraulics phenomena (e.g., two-phase flow, heat transfer, phase change, coolant dynamics, and liquid metal flow).

  6. Extracting source parameters from beam monitors on a chopper spectrometer

    SciTech Connect

    Abernathy, Douglas L; Niedziela, Jennifer L; Stone, Matthew B

    2015-01-01

    The intensity distributions of beam monitors in direct-geometry time-of-flight neutron spectrometers provide important information about the instrument resolution. For short-pulse spallation neutron sources in particular, the asymmetry of the source pulse may be extracted and compared to Monte Carlo source simulations. An explicit formula using a Gaussian-convolved Ikeda-Carpenter distribution is given and compared to data from the ARCS instrument at the Spallation Neutron Source.

  7. SU-E-T-484: In Vivo Dosimetry Tolerances in External Beam Fast Neutron Therapy

    SciTech Connect

    Young, L; Gopan, O

    2015-06-15

    Purpose: Optical stimulated luminescence (OSL) dosimetry with Landauer Al2O3:C nanodots was developed at our institution as a passive in vivo dosimetry (IVD) system for patients treated with fast neutron therapy. The purpose of this study was to establish clinically relevant tolerance limits for detecting treatment errors requiring further investigation. Methods: Tolerance levels were estimated by conducting a series of IVD expected dose calculations for square field sizes ranging between 2.8 and 28.8 cm. For each field size evaluated, doses were calculated for open and internal wedged fields with angles of 30°, 45°, or 60°. Theoretical errors were computed for variations of incorrect beam configurations. Dose errors, defined as the percent difference from the expected dose calculation, were measured with groups of three nanodots placed in a 30 x 30 cm solid water phantom, at beam isocenter (150 cm SAD, 1.7 cm Dmax). The tolerances were applied to IVD patient measurements. Results: The overall accuracy of the nanodot measurements is 2–3% for open fields. Measurement errors agreed with calculated errors to within 3%. Theoretical estimates of dosimetric errors showed that IVD measurements with OSL nanodots will detect the absence of an internal wedge or a wrong wedge angle. Incorrect nanodot placement on a wedged field is more likely to be caught if the offset is in the direction of the “toe” of the wedge where the dose difference in percentage is about 12%. Errors caused by an incorrect flattening filter size produced a 2% measurement error that is not detectable by IVD measurement alone. Conclusion: IVD with nanodots will detect treatment errors associated with the incorrect implementation of the internal wedge. The results of this study will streamline the physicists’ investigations in determining the root cause of an IVD reading that is out of normally accepted tolerances.

  8. Advanced Penning-type ion source development and passive beam focusing techniques for an associated particle imaging neutron generator with enhanced spatial resolution

    NASA Astrophysics Data System (ADS)

    Sy, Amy Vong

    The use of accelerator-based neutron generators for non-destructive imaging and analysis in commercial and security applications is continuously under development, with improvements to available systems and combinations of available techniques revealing new capabilities for real-time elemental and isotopic analysis. The recent application of associated particle imaging (API) techniques for time- and directionally-tagged neutrons to induced fission and transmission imaging methods demonstrates such capabilities in the characterization of fissile material configurations and greatly benefits from improvements to existing neutron generator systems. Increased neutron yields and improved spatial resolution can enhance the capabilities of imaging methods utilizing the API technique. The work presented in this dissertation focused on the development of components for use within an API neutron generator with enhanced system spatial resolution. The major focus areas were the ion source development for plasma generation, and passive ion beam focusing techniques for the small ion beam widths necessary for the enhanced spatial resolution. The ion source development focused on exploring methods for improvement of Penning-type ion sources that are used in conventional API neutron generator systems, while the passive beam focusing techniques explored both ion beam collimation and ion guiding with tapered dielectric capillaries for reduced beam widths at the neutron production target.

  9. A new automated sample transfer system for instrumental neutron activation analysis.

    PubMed

    Ismail, S S

    2010-01-01

    A fully automated and fast pneumatic transport system for short-time activation analysis was recently developed. It is suitable for small nuclear research reactors or laboratories that are using neutron generators and other neutron sources. It is equipped with a programmable logic controller, software package, and 12 devices to facilitate optimal analytical procedures. 550 ms were only necessary to transfer the irradiated capsule (diameter: 15 mm, length: 50 mm, weight: 4 gram) to the counting chamber at a distance of 20 meters using pressurized air (4 bars) as a transport gas.

  10. A New Automated Sample Transfer System for Instrumental Neutron Activation Analysis

    PubMed Central

    Ismail, S. S.

    2010-01-01

    A fully automated and fast pneumatic transport system for short-time activation analysis was recently developed. It is suitable for small nuclear research reactors or laboratories that are using neutron generators and other neutron sources. It is equipped with a programmable logic controller, software package, and 12 devices to facilitate optimal analytical procedures. 550 ms were only necessary to transfer the irradiated capsule (diameter: 15 mm, length: 50 mm, weight: 4 gram) to the counting chamber at a distance of 20 meters using pressurized air (4 bars) as a transport gas. PMID:20369063

  11. Radio metric errors due to mismatch and offset between a DSN antenna beam and the beam of a troposphere calibration instrument

    NASA Technical Reports Server (NTRS)

    Linfield, R. P.; Wilcox, J. Z.

    1993-01-01

    Two components of the error of a troposphere calibration measurement were quantified by theoretical calculations. The first component is a beam mismatch error, which occurs when the calibration instrument senses a conical volume different from the cylindrical volume sampled by a Deep Space Network (DSN) antenna. The second component is a beam offset error, which occurs if the calibration instrument is not mounted on the axis of the DSN antenna. These two error sources were calculated for both delay (e.g., VLBI) and delay rate (e.g., Doppler) measurements. The beam mismatch error for both delay and delay rate drops rapidly as the beamwidth of the troposphere calibration instrument (e.g., a water vapor radiometer or an infrared Fourier transform spectrometer) is reduced. At a 10-deg elevation angle, the instantaneous beam mismatch error is 1.0 mm for a 6-deg beamwidth and 0.09 mm for a 0.5-deg beam (these are the full angular widths of a circular beam with uniform gain out to a sharp cutoff). Time averaging for 60-100 sec will reduce these errors by factors of 1.2-2.2. At a 20-deg elevation angle, the lower limit for current Doppler observations, the beam-mismatch delay rate error is an Allan standard deviation over 100 sec of 1.1 x 10(exp -14) with a 4-deg beam and 1.3 x 10(exp -l5) for a 0.5-deg beam. A 50-m beam offset would result in a fairly modest (compared to other expected error sources) delay error (less than or equal to 0.3 mm for 60-sec integrations at any elevation angle is greater than or equal to 6 deg). However, the same offset would cause a large error in delay rate measurements (e.g., an Allan standard deviation of 1.2 x 10(exp -14) over 100 sec at a 20-deg elevation angle), which would dominate over other known error sources if the beamwidth is 2 deg or smaller. An on-axis location is essential for accurate troposphere calibration of delay rate measurements. A half-power beamwidth (for a beam with a tapered gain profile) of 1.2 deg or smaller is

  12. Neutron measurements in the stray field produced by 158 GeV c(-1) per nucleon lead ion beams.

    PubMed

    Agosteo, S; Birattari, C; Foglio Para, A; Nava, E; Silari, M; Ulrici, L

    1998-12-01

    This paper discusses measurements carried out at CERN in the stray radiation field produced by 158 GeV c(-1) per nucleon 208Pb82+ ions. The purpose was to test and intercompare the response of several detectors, mainly neutron measuring devices, and to determine the neutron spectral fluence as well as the microdosimetric (absorbed dose and dose equivalent) distributions in different locations around the shielding. Both active instruments and passive dosimeters were employed, including different types of Andersson-Braun rem counters, a tissue equivalent proportional counter, a set of superheated drop detectors, a Bonner sphere system, and different types of ion chambers. Activation measurements with 12C plastic scintillators and with 32S pellets were also performed to assess the neutron yield of high energy lead ions interacting with a thin gold target. The results are compared with previous measurements and with measurements made during proton runs.

  13. Characterization of an explosively bonded aluminum proton beam window for the Spallation Neutron Source

    SciTech Connect

    McClintock, David A; Janney, Jim G; Parish, Chad M

    2014-01-01

    An effort is underway at the Spallation Neutron Source (SNS) to change the design of the 1st Generation high-nickel alloy proton beam window (PBW) to one that utilizes aluminum for the window material. One of the key challenges to implementation of an aluminum PBW at the SNS was selection of an appropriate joining method to bond an aluminum window to the stainless steel bulk shielding of the PBW assembly. An explosively formed bond was selected as the most promising joining method for the aluminum PBW design. A testing campaign was conducted to evaluate the strength and efficacy of explosively formed bonds that were produced using two different interlayer materials: niobium and titanium. The characterization methods reported here include tensile testing, thermal-shock leak testing, optical microscopy, and advanced scanning electron microscopy. All tensile specimens examined failed in the aluminum interlayer and measured tensile strengths were all slightly greater than the native properties of the aluminum interlayer, while elongation values were all slightly lower. A leak developed in the test vessel with a niobium interlayer joint after repeated thermal-shock cycles, and was attributed to an extensive crack network that formed in a layer of niobium-rich intermetallics located on the bond interfaces of the niobium interlayer; the test vessel with a titanium interlayer did not develop a leak under the conditions tested. Due to the experience gained from these characterizations, the explosively formed bond with a titanium interlayer was selected for the aluminum PBW design at the SNS.

  14. A novel approach to neutron scattering instrumentation for probing multiscale dynamics in soft and biological matter

    DOE PAGES

    Mamontov, Eugene

    2016-06-29

    We present a concept and ray-tracing simulation results of a mechanical device that will enable inelastic neutron scattering measurements where the data at energy transfers from a few eV to several hundred meV can be collected in a single, gapless spectrum. Besides covering 5 orders of magnitude on the energy (time) scale, the device provides data over 2 orders of magnitude on the scattering momentum (length) scale in a single measurement. Such capabilities are geared primarily toward soft and biological matter, where the broad dynamical features of relaxation origin largely overlap with vibration features, thus necessitating gapless spectral coverage overmore » several orders of magnitude in time and space. Furthermore, neutron scattering experiments with such a device are performed with a fixed neutron final energy, which enables measurements, with neutron energy loss in the sample, at arbitrarily low temperatures over the same broad spectral range. Lastly, this capability is also invaluable in biological and soft matter research, as the variable temperature dependence of different relaxation components allows their separation in the scattering spectra as a function of temperature.« less

  15. A novel approach to neutron scattering instrumentation for probing multiscale dynamics in soft and biological matter

    SciTech Connect

    Mamontov, Eugene

    2016-06-29

    We present a concept and ray-tracing simulation results of a mechanical device that will enable inelastic neutron scattering measurements where the data at energy transfers from a few eV to several hundred meV can be collected in a single, gapless spectrum. Besides covering 5 orders of magnitude on the energy (time) scale, the device provides data over 2 orders of magnitude on the scattering momentum (length) scale in a single measurement. Such capabilities are geared primarily toward soft and biological matter, where the broad dynamical features of relaxation origin largely overlap with vibration features, thus necessitating gapless spectral coverage over several orders of magnitude in time and space. Furthermore, neutron scattering experiments with such a device are performed with a fixed neutron final energy, which enables measurements, with neutron energy loss in the sample, at arbitrarily low temperatures over the same broad spectral range. Lastly, this capability is also invaluable in biological and soft matter research, as the variable temperature dependence of different relaxation components allows their separation in the scattering spectra as a function of temperature.

  16. A novel approach to neutron scattering instrumentation for probing multiscale dynamics in soft and biological matter

    NASA Astrophysics Data System (ADS)

    Mamontov, Eugene

    2016-09-01

    We present a concept and ray-tracing simulation of a mechanical device that will enable inelastic neutron scattering measurements where the data at energy transfers from a few μeV to several hundred meV can be collected in a single, gapless spectrum. Besides covering 5 orders of magnitude on the energy (time) scale, the device provides data over 2 orders of magnitude on the scattering momentum (length) scale in a single measurement. Such capabilities are geared primarily toward soft and biological matter, where the broad dynamical features of relaxation origin largely overlap with vibration features, thus necessitating gapless spectral coverage over several orders of magnitude in time and space. Furthermore, neutron scattering experiments with such a device are performed with a fixed neutron final energy, which enables measurements, with neutron energy loss in the sample, at arbitrarily low temperatures over the same broad spectral range. This capability is also invaluable in biological and soft matter research, as the variable temperature dependence of different relaxation components allows their separation in the scattering spectra as a function of temperature.

  17. New Spherical Gamma-Ray and Neutron Emitting Sources for Testing of Radiation Detection Instruments

    PubMed Central

    Lucas, L.; Pibida, L.

    2009-01-01

    The National Institute of Standards and Technology (NIST) has developed new gamma-ray and neutron emitting sources for testing radiation detection systems. These radioactive sources were developed for testing of detection systems in maritime applications. This required special source characteristics. PMID:27504230

  18. Novel neutron focusing mirrors for compact neutron sources

    NASA Astrophysics Data System (ADS)

    Khaykovich, B.; Gubarev, M. V.; Zavlin, V. E.; Katz, R.; Resta, G.; Liu, D.; Robertson, L.; Crow, L.; Ramsey, B. D.; Moncton, D. E.

    We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. A system containing four nested Ni mirror pairs was implemented and tested by focusing a polychromatic neutron beam at the MIT Reactor and conducting an imaging experiment at HFIR. The major advantage of the Wolter mirrors is the possibility of nesting for large angular collection. Using nesting, the relatively short optics can be made comparable to focusing guides in flux collection capabilities. We discuss how such optics can be used as polychromatic lenses to improve the performance of small-angle-scattering, imaging, and other instruments at compact neutron sources.

  19. Design and optimization of a beam shaping assembly for BNCT based on D-T neutron generator and dose evaluation using a simulated head phantom.

    PubMed

    Rasouli, Fatemeh S; Masoudi, S Farhad

    2012-12-01

    A feasibility study was conducted to design a beam shaping assembly for BNCT based on D-T neutron generator. The optimization of this configuration has been realized in different steps. This proposed system consists of metallic uranium as neutron multiplier, TiF(3) and Al(2)O(3) as moderators, Pb as reflector, Ni as shield and Li-Poly as collimator to guide neutrons toward the patient position. The in-air parameters recommended by IAEA were assessed for this proposed configuration without using any filters which enables us to have a high epithermal neutron flux at the beam port. Also a simulated Snyder head phantom was used to evaluate dose profiles due to the irradiation of designed beam. The dose evaluation results and depth-dose curves show that the neutron beam designed in this work is effective for deep-seated brain tumor treatments even with D-T neutron generator with a neutron yield of 2.4×10(12) n/s. The Monte Carlo Code MCNP-4C is used in order to perform these calculations.

  20. Thermal and resonance neutrons generated by various electron and X-ray therapeutic beams from medical linacs installed in polish oncological centers

    PubMed Central

    Konefał, Adam; Orlef, Andrzej; Łaciak, Marcin; Ciba, Aleksander; Szewczuk, Marek

    2012-01-01

    Background High-energy photon and electron therapeutic beams generated in medical linear accelerators can cause the electronuclear and photonuclear reactions in which neutrons with a broad energy spectrum are produced. A low-energy component of this neutron radiation induces simple capture reactions from which various radioisotopes originate and in which the radioactivity of a linac head and various objects in the treatment room appear. Aim The aim of this paper is to present the results of the thermal/resonance neutron fluence measurements during therapeutic beam emission and exemplary spectra of gamma radiation emitted by medical linac components activated in neutron reactions for four X-ray beams and for four electron beams generated by various manufacturers’ accelerators installed in typical concrete bunkers in Polish oncological centers. Materials and methods The measurements of neutron fluence were performed with the use of the induced activity method, whereas the spectra of gamma radiation from decays of the resulting radioisotopes were measured by means of a portable high-purity germanium detector set for field spectroscopy. Results The fluence of thermal neutrons as well as resonance neutrons connected with the emission of a 20 MV X-ray beam is ∼106 neutrons/cm2 per 1 Gy of a dose in water at a reference depth. It is about one order of magnitude greater than that for the 15 MV X-ray beams and about two orders of magnitude greater than for the 18–22 MeV electron beams regardless of the type of an accelerator. Conclusion The thermal as well as resonance neutron fluence depends strongly on the type and the nominal potential of a therapeutic beam. It is greater for X-ray beams than for electrons. The accelerator accessories and other large objects should not be stored in a treatment room during high-energy therapeutic beam emission to avoid their activation caused by thermal and resonance neutrons. Half-lives of the radioisotopes originating from

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  2. Nutrient elements of commercial tea from Nigeria by an instrumental neutron activation analysis technique.

    PubMed

    Jona, S A; Williams, I S

    2000-08-30

    A prototype miniature neutron source reactor (MNSR) with a thermal neutron flux of 3.0 x 10(11) n cm(-2) s(-1) has been used to determine the concentrations of some nutrient elements leading to short-lived activation products in commercial tea leaf samples from Nigeria. A total of eight elements Al, Ca, Cl, Cu, K, Mg, Mn and Na, that can be routinely used for quality control purposes, were analyzed in this study. Two biological reference materials, tomato leaves (NIST-1573) and citrus leaves (NIST-1572) were used as the standard and quality control materials, respectively. The analytical results show that the average concentrations of Al, Ca, Cl, Cu, K, Mg, Mn and Na in Nigerian tea are slightly higher when compared with a Chinese herbal tea analyzed in this study. The concentration ratios of K/Ca were found to be high in all the samples analyzed suggesting cultivation in potash-rich soils.

  3. Investigation of the atmospheric particulates deposited on leaves using instrumental neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Cercasov, V.

    A method for the separation of surface contamination on plant leaves by plastic film stripping was applied. The particulate matter embedded in the film was analysed by neutron activation. The investigation was directed especially towards the determination of the trace element content of the suitable plastic matrices and of the influence of solvents. The practicability of this method is demonstrated by analysing films stripped from plant leaves with different degrees of pollution.

  4. Determination of Pu content in a Spent Fuel Assembly by Measuring Passive Total Neutron count rate and Multiplication with the Differential Die-Away Instrument

    SciTech Connect

    Henzl, Vladimir; Croft, Stephen; Swinhoe, Martyn T.; Tobin, Stephen J.

    2012-07-13

    Inspired by approach of Bignan and Martin-Didier (ESARDA 1991) we introduce novel (instrument independent) approach based on multiplication and passive neutron. Based on simulations of SFL-1 the accuracy of determination of {sup tot}Pu content with new approach is {approx}1.3-1.5%. Method applicable for DDA instrument, since it can measure both multiplication and passive neutron count rate. Comparison of pro's & con's of measuring/determining of {sup 239}Pu{sub eff} and {sup tot}Pu suggests a potential for enhanced diversion detection sensitivity.

  5. Are neutrons responsible for the dose discrepancies between Monte Carlo calculations and measurements in the build-up region for a high-energy photon beam?

    PubMed

    Ding, George X; Duzenli, Cheryl; Kalach, Nina I

    2002-09-07

    This study presents measured neutron dose using a neutron dosimeter in a water phantom and investigates a hypothesis that neutrons in a high-energy photon beam may be responsible for the reported significant dose discrepancies between Monte Carlo calculations and measurements at the build-up region in large fields. Borated polyethylene slabs were inserted between the accelerator head and the phantom in order to remove neutrons generated in the accelerator head. The thickness of the slab ranged from 2.5 cm to 10 cm. A lead slab of 3 mm thickness was also used in the study. The superheated drop neutron dosimeter was used to measure the depth-dose curve of neutrons in a high-energy photon beam and to verify the effectiveness of the slab to remove these neutrons. Total dose measurements were performed in water using a WELLHOFER WP700 beam scanner with an IC-10 ionization chamber. The Monte Carlo code BEAM was used to simulate an 18 MV photon beam from a Varian Clinac-2100EX accelerator. Both EGS4/DOSXYZ and EGSnrc/DOSRZnrc were used in the dose calculations. Measured neutron dose equivalents as a function of depth per unit total dose in water were presented for 10 x 10 and 40 x 40 cm2 fields. The measured results have shown that a 5-10 cm thick borated polyethylene slab can reduce the neutron dose by a factor of 2 when inserted between the accelerator head and the detector. In all cases the measured neutron dose equivalent was less than 0.5% of the photon dose. In order to study if the ion chamber was highly sensitive to the neutron dose, we have investigated the disagreement between the Monte Carlo calculated and measured central-axis depth-dose curves in the build-up region when different shielding materials were used. The result indicated that the IC-10 chamber was not highly sensitive to the neutron dose. Therefore, neutrons present in a high-energy photon beam were unlikely to be responsible for the reported discrepancies in the build-up region for large fields.

  6. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    SciTech Connect

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-14

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E < 12.47% for 99% particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 10{sup 11} n/cm{sup 2}/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  7. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-01

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E < 12.47% for 99% particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 1011 n/cm2/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

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

    DOE PAGES

    Muhrer, Guenter; Schönfeldt, Troels; Iverson, Erik B.; ...

    2016-06-14

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

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

    SciTech Connect

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

    2016-06-14

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

  10. 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.

  11. Studies on the shielding properties of polyboron and ilmenite-magnetite concrete using a reactor neutron beam

    SciTech Connect

    Ahmed, F.U.; Bhuiyan, S.I.; Mollah, A.S.; Sarder, M.R.; Huda, M.Q.; Rahman, M.; Mondal, M.A.W.

    1999-05-01

    The shielding effectiveness of locally developed polyboron and ilmenite-magnetite (I-M) concrete is investigated using the reactor neutron beam of the 3-MW TRIGA Mark II research reactor at the Atomic Energy Research Establishment, Savar, Dhaka. The effective removal cross sections for the foregoing individual shielding materials as well as their combinations are obtained from transmission data using two-group neutron fluxes defined by a Cd-cutoff value. The experimental transmission factors for I-M concrete and polyboron are compared with those obtained from transport calculations performed with the ANISN deterministic code in the forward mode and the MCNP4B Monte Carlo code. The ANISN code is used for the fast neutron group flux (Cd-cutoff flux), and the MCNP4B code is used for the total neutron flux. The agreement between the experiment and calculation is fairly good at deep penetration, but at initial points, some disagreement is observed. This observation is valid for both polyboron and I-M concrete.

  12. Core Vessel Insert Handling Robot for the Spallation Neutron Source

    SciTech Connect

    Graves, Van B; Dayton, Michael J

    2011-01-01

    The Spallation Neutron Source provides the world's most intense pulsed neutron beams for scientific research and industrial development. Its eighteen neutron beam lines will eventually support up to twenty-four simultaneous experiments. Each beam line consists of various optical components which guide the neutrons to a particular instrument. The optical components nearest the neutron moderators are the core vessel inserts. Located approximately 9 m below the high bay floor, these inserts are bolted to the core vessel chamber and are part of the vacuum boundary. They are in a highly radioactive environment and must periodically be replaced. During initial SNS construction, four of the beam lines received Core Vessel Insert plugs rather than functional inserts. Remote replacement of the first Core Vessel Insert plug was recently completed using several pieces of custom-designed tooling, including a highly complicated Core Vessel Insert Robot. The design of this tool are discussed.

  13. Optimization of Beam-Shaping Assemblies for BNCS Using the High-Energy Neutron Sources D-D and D-T

    SciTech Connect

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

    2001-06-15

    Boron neutron capture synovectomy is a novel approach for the treatment of rheumatoid arthritis. The goal of the treatment is the ablation of diseased synovial membranes in articulating joints. The treatment of knee joints is the focus of this work. A method was developed, as discussed previously, to predict the dose distribution in a knee joint from any neutron and photon beam spectra incident on the knee. This method is validated and used to design moderators for the deuterium-deuterium (D-D) and deuterium-tritium (D-T) neutron sources. Treatment times >2 h were obtained with the D-D reaction. They could potentially be reduced if the {sup 10}B concentration in the synovium was increased. For D-T neutrons, high therapeutic ratios and treatment times <5 min were obtained for neutron yields of 10{sup 14} s{sup -1}. This treatment time makes the D-T reaction attractive for boron neutron capture synovectomy.

  14. High rejection VNIR-SWIR beam splitter for the multispectral instrument of Sentinel 2

    NASA Astrophysics Data System (ADS)

    Moreau, V.; Lappschies, M.; Camus, F.; Kirschner, V.; Haas, C.

    2013-10-01

    The Sentinel 2 mission shall ensure the continuity and enhancement of Landsat and SPOT data and sustain operational land services in the frame of the Global Monitoring for Environment and Security (GMES) initiative. Sentinel-2 is designed to image the Earth's landmasses from its orbit for at least 7.25 years. The Multi-Spectral Instrument (MSI), delivered by Astrium Toulouse, will provide high resolution imagery in 13 spectral channels extending from the Visible Near Infrared (VNIR, 400-1100 nm) to the Short Wave Infra-Red (SWIR, 1100-2500 nm) range, down to a resolution of 10 meters with an image width of 290 kilometers. A dichroic splitter device is located in back-focal path of the telescope. It allows splitting the incoming optical beam between VNIR and SWIR focal planes. It shall ensure an extremely high rejection, better than 1:1000, between both ranges while introducing negligible aberrations in reflected (VNIR) and transmitted (SWIR) paths. The splitter assembly consists of a wedged dichroic filter plate and a wedged compensator plate mounted in a common frame. Both plates are made of fused silica (Infrasil) and polished to lambda/40. The major challenges reside in the design complexity of the dichroic coating and in the deposition process control to ensure the required high uniformity of performances through the large aperture. The paper presents the final spectral and optical performances of this challenging sub-system. It also discusses the main difficulties that have been overpassed during the development and qualification phase.

  15. A Positional X-ray Instrumentation Test Stand For Beam-Line Experiments

    NASA Astrophysics Data System (ADS)

    Nikoleyczik, Jonathan; Prieskorn, Z.; Burrows, D. N.; Falcone, A.

    2014-01-01

    A multi-axis, motion controlled test stand has been built in the PSU 47 m X-ray beam-line for the purpose of testing X-ray instrumentation and mirrors using parallel rays. The test stand is capable of translation along two axes and rotation about two axes with motorized fine position control. The translation stages have a range of motion of 200 mm with a movement accuracy of ± 2.5 microns. Rotation is accomplished with a two-axis gimbal which can rotate 360° about one axis and 240° about another; movement with ± 35 arcsecond accuracy are achieved in both axes. The position and status are monitored using a LabView program. An XCalibr source with multiple target materials is used as an X-ray source and can produce multiple lines between 0.8 and 8 keV. Some sample spectra are shown from a Si-PIN diode detector. This system is well suited for testing X-ray mirror segments which are currently being developed.

  16. Instrumental neutron activation analysis errors and interferences during the certification analysis of NIST SRM 1573a tomato leaves (renewal)

    SciTech Connect

    Becker, D.A.

    1992-01-01

    The National Institute of Standards and Technology is in the process of certification for a new supply of the botanical standard reference material (SRM) 1573, tomato leaves. This renewal SRM 1573a has already been analyzed by instrumental neutron activation analysis (INAA) for 18 elements with 12 replicates and sample sizes averaging {approximately}140 mg. Elements determined by INAA were selected according to the needs of the SRM program and include some with short half-lives (aluminum, vanadium, calcium, magnesium), some with intermediate half-lives (sodium, potassium, manganese, barium, lanthanum, rubidium), and some with long half-lives (iron, chromium, zinc, cobalt, selenium, thorium, scandium, and antimony). The data obtained will also be used for homogeneity evaluation. During the initial evaluation and certification analyses, a number of potential errors and interferences were identified.

  17. Investigation of chemical impurities in formulations, phytotherapics and polyvitaminic medicines by k0-instrumental neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Leal, A. S.; Menezes, M. Â. B. C.; Vermaercke, P.; Sneyers, L.; Jensen, C. E. M.

    2006-08-01

    In this work, comparative k0-Instrumental Neutron-Activation Analysis was performed by CDTN/CNEN/Brazil and SCK.CEN/Belgium in order to investigate the elemental concentration in samples of the same industrialised and manipulated medicine, a phytotherapic and a polyvitaminic, commonly commercialised in Brazil. The preliminary results from both Institutes are in very good agreement. Any serious contamination with possible risks to human health were found in the medicines compared with the expected values. In the case of polyvitaminic, some impurities, unexpected elements, such as La, Ti and Sm, were found in very low concentration. This first assessment confirmed the effectiveness of the k0-method in analysing such matrices.

  18. Elemental analysis of granite by instrumental neutron activation analysis (INAA) and X-ray fluorescence analysis (XRF).

    PubMed

    El-Taher, A

    2012-01-01

    The instrumental neutron activation analysis technique (INAA) was used for qualitative and quantitative analysis of granite samples collected from four locations in the Aswan area in South Egypt. The samples were prepared together with their standards and simultaneously irradiated in a neutron flux of 7×10(11)n/cm(2)s in the TRIGA Mainz research reactor. Gamma-ray spectra from an hyper-pure germanium detector were analyzed. The present study provides the basic data of elemental concentrations of granite rocks. The following elements have been determined Na, Mg, K, Fe, Mn, Sc, Cr, Ti, Co, Zn, Ga, Rb, Zr, Nb, Sn, Ba, Cs, La, Ce, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. The X-ray fluorescence (XRF) was used for comparison and to detect elements, which can be detected only by XRF such as F, S, Cl, Co, Cu, Mo, Ni, Pb, Se and V. The data presented here are our contribution to understanding the elemental composition of the granite rocks. Because there are no existing databases for the elemental analysis of granite, our results are a start to establishing a database for the Egyptian granite. It is hoped that the data presented here will be useful to those dealing with geochemistry, granite chemistry and related fields.

  19. Rare earth elements content in geological samples from eastern desert, Egypt, determined by instrumental neutron activation analysis.

    PubMed

    El-Taher, A

    2010-09-01

    Twenty representative geological samples (tonalite, granodiorite, adamellite, syenogranite, rapakivi syenogranite, alkali feldspar granite and monzogranite) were collected from G. Kattar area in Eastern Desert, Egypt, for analysis by instrumental neutron activation as a sensitive nondestructive analytical tool for the determination of 14 rare earth elements (REEs) and to find out the following: (1) what information could be obtained about the REEs and distribution patterns of REEs in geological samples under investigation, (2) to estimate the accuracy, reproducibility and detection limit of the INAA method in case of the given samples. The samples were properly prepared together with standard reference material and simultaneously irradiated in a neutron flux of 7x10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The gamma spectra were collected by an HPGe detector and the analysis was done by means of a computerized multichannel analyzer. The choice of the nuclear reaction, irradiation and decay times, and of the proper gamma radiation in counting are presented and discussed. The results are found to be in good agreement with certified values.

  20. Multielement analysis of human hair and kidney stones by instrumental neutron activation analysis with the k0-standardization method.

    PubMed

    Abugassa, I; Sarmani, S B; Samat, S B

    1999-06-01

    This paper focuses on the evaluation of the k0 method of instrumental neutron activation analysis in biological materials. The method has been applied in multielement analysis of human hair standard reference materials from IAEA, No. 085, No. 086 and from NIES (National Institute for Environmental Sciences) No. 5. Hair samples from people resident in different parts of Malaysia, in addition to a sample from Japan, were analyzed. In addition, human kidney stones from members of the Malaysian population have been analyzed for minor and trace elements. More than 25 elements have been determined. The samples were irradiated in the rotary rack (Lazy Susan) at the TRIGA Mark II reactor of the Malaysian Institute for Nuclear Technology and Research (MINT). The accuracy of the method was ascertained by analysis of other reference materials, including 1573 tomato leaves and 1572 citrus leaves. In this method the deviation of the 1/E1+ alpha epithermal neutron flux distribution from the 1/E law (P/T ratio) for true coincidence effects of the gamma-ray cascade and the HPGe detector efficiency were determined and corrected for.

  1. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    DOE PAGES

    Wang, Hsiu -Wen; Fanelli, Victor R.; Reiche, Helmut M.; ...

    2014-12-24

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO2measurements. Asmore » a result, the new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H2 and natural gas uptake/storage.« less

  2. Monte Carlo simulations as a part of the configuration for neutron instruments

    NASA Astrophysics Data System (ADS)

    Andersen, P.; Lefmann, K.; Theil Kuhn, L.; Willendrup, P. K.; Farhi, E.

    2004-07-01

    We demonstrate the use of simulations in the process of determining the optimal instrument setup by virtual experiments using the simulation package McStas. The focus of the analysis is the optimization of the multi-blade analyzer present at the RITA-II spectrometer at PSI for a test experiment with powder diffraction. The agreement in resolution and signal-to-background ratio between measurements and simulations shows the validity of the approach. For a sample with broadened Bragg peaks, the optimal instrument configuration could be established only on careful consideration. This shows that in general instrument simulations are approaching a state where they can assist users in selecting the optimal configuration and possibly demonstrate the feasibility of their experiments prior to allocated beamtime.

  3. Upgrade of the neutron guide system at the OPAL Neutron Source

    NASA Astrophysics Data System (ADS)

    Rodriguez, D. Martin; Kennedy, S. J.; Klose, F.

    2010-11-01

    The new research reactor at ANSTO (OPAL) is operating with seven neutron beam instruments in the user programme and three more under construction. The reactor design provides for expansion of the facility to eighteen instruments, and much of the basic infrastructure is already in place. However, an expansion of the neutron guide system is needed for further beam instruments. For this purpose, several possibilities are under consideration, such as insertion of multi-channel neutron benders in the existing cold guides or the construction of a new elliptic cold guide. In this work Monte Carlo (MC) simulations have been used to evaluate performance of these guide configurations. Results show that these configurations can be competitive with the best instruments in the world.

  4. Delayed neutron fraction and prompt decay constant measurement in the MINERVE reactor using the PSI instrumentation

    SciTech Connect

    Perret, Gregory

    2015-07-01

    The critical decay constant (B/A), delayed neutron fraction (B) and generation time (A) of the Minerve reactor were measured by the Paul Scherrer Institut (PSI) and the Commissariat a l'Energie Atomique (CEA) in September 2014 using the Feynman-alpha and Power Spectral Density neutron noise measurement techniques. Three slightly subcritical configuration were measured using two 1-g {sup 235}U fission chambers. This paper reports on the results obtained by PSI in the near critical configuration (-2g). The most reliable and precise results were obtained with the Cross-Power Spectral Density technique: B = 708.4±9.2 pcm, B/A = 79.0±0.6 s{sup -1} and A 89.7±1.4 micros. Predictions of the same kinetic parameters were obtained with MCNP5-v1.6 and the JEFF-3.1 and ENDF/B-VII.1 nuclear data libraries. On average the predictions for B and B/A overestimate the experimental results by 5% and 11%, respectively. The discrepancy is suspected to come from either a corruption of the data or from the inadequacy of the point kinetic equations to interpret the measurements in the Minerve driven system. (authors)

  5. Using instrumental neutron activation analysis for geochemical analyses of terrestrial impact structures: current analytical procedures at the university of vienna geochemistry activation analysis laboratory.

    PubMed

    Mader, Dieter; Koeberl, Christian

    2009-12-01

    The Instrumental Neutron Activation Analysis Gamma Spectroscopy Laboratory at the Department of Lithospheric Research, University of Vienna, has been upgraded in the year 2006. This paper describes the sample preparation, new instrumentation and data evaluation for hundreds of rock samples of two terrestrial impact structures. The measurement and data evaluation are done by using Genie 2000 and a custom-made batch software for the used analysis sequences.

  6. Production of ultracold neutrons from a cold neutron beam on a {sup 2}H{sub 2} target

    SciTech Connect

    Atchison, F.; Brandt, B. van den; Brys, T.; Daum, M.; Fierlinger, P.; Hautle, P.; Henneck, R.; Heule, S.; Kasprzak, M.; Kirch, K.; Konter, J.A.; Michels, A.; Pichlmaier, A.; Wohlmuther, M.; Wokaun, A.; Bodek, K.; Szerer, U.; Geltenbort, P.; Zmeskal, J.; Pokotilovskiy, Y.

    2005-05-01

    The production rates of ultracold neutrons (UCN) from cold neutrons on gaseous, liquid, and solid deuterium targets have been measured. The comparison of the measured and calculated UCN production on gaseous {sup 2}H{sub 2} is used to calibrate the simulated target extraction and transport efficiencies of the experimental apparatus. The production cross section in solid {sup 2}H{sub 2} at 8 K for UCN with energies between 0 and 250 neV is R{sub solid,8K}={sigma}{sub solid,8K}{sup CN{yields}}U{sup CN} {rho}=(1.11{+-}0.23)x10{sup -8} cm{sup -1}. This value is consistent with other experiments in which UCN had been extracted from {sup 2}H{sub 2}. The value also agrees with calculations using the incoherent approximation and a simple Debye model and corroborates predictions for UCN densities expected at the high-intensity UCN source at the Paul Scherrer Institut. The temperature dependence of the UCN production in solid {sup 2}H{sub 2} down to 8 K can be explained within the same model when multiple-phonon excitation is included.

  7. Production of beams of neutron-rich nuclei between Ca and Ni using the ion-guide technique

    SciTech Connect

    Perajarvi, K.; Cerny, J.; Hager, U.; Hakala, J.; Huikari, J.; Jokinen, A.; Karvonen, P.; Kurpeta, J.; Lee, D.; Moore, I.; Penttila, H.; Popov, A.; Aysto, J.

    2004-09-28

    Since several elements between Z = 20-28 are refractory in their nature, their neutron-rich isotopes are rarely available as low energy Radioactive Ion Beams (RIB) in ordinary Isotope Separator On-Line facilities [1-4]. These low energy RIBs would be especially interesting to have available under conditions which allow high-resolution beta-decay spectroscopy, ion-trapping and laser-spectroscopy. As an example, availability of these beams would open a way for research which could produce interesting and important data on neutron-rich nuclei around the doubly magic {sup 78}Ni. One way to overcome the intrinsic difficulty of producing these beams is to rely on the chemically unselective Ion Guide Isotope Separator On-Line (IGISOL) technique [5]. Quasi- and deep-inelastic reactions, such as {sup 197}Au({sup 65}Cu,X)Y, could be used to produce these nuclei in existing IGISOL facilities, but before they can be successfully incorporated into the IGISOL concept their kinematics must be well understood. Therefore the reaction kinematics part of this study was first performed at the Lawrence Berkeley National Laboratory using its 88'' cyclotron and, based on those results, a specialized target chamber was built[6]. The target chamber shown in Fig. 1 was recently tested on-line at the Jyvaaskylaa IGISOL facility. Yields of mass-separated radioactive projectile-like species such as {sup 62,63}Co are about 0.8 ions/s/pnA, corresponding to about 0.06 % of the total IGISOL efficiency for the products that hit the Ni-degrader. (The current maximum 443 MeV {sup 65}Cu beam intensity at Jyvaaskylaa is about 20 pnA.) This total IGISOL efficiency is a product of two coupled loss factors, namely inadequate thermalization and the intrinsic IGISOL efficiency. In our now tested chamber, about 9 % of the Co recoils are thermalized in the owing He gas (p{sub He}=300 mbar) and about 0.7 % of them are converted into the mass-separated ion beams. In the future, both of these physical

  8. High energy neutron radiography

    SciTech Connect

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-06-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos.

  9. Near and sub-barrier fusion of neutron-rich oxygen and carbon nuclei using low-intensity beams

    NASA Astrophysics Data System (ADS)

    Steinbach, Tracy K.

    Fusion between neutron-rich light nuclei in the crust of an accreting neutron star has been proposed as a heat source that triggers an X-ray superburst. To explore the probability with which such fusion events occur and examine their decay characteristics, an experimental program using beams of neutron-rich light nuclei has been established. Evaporation residues resulting from the fusion of oxygen and 12C nuclei, are directly measured and distinguished from unreacted beam particles on the basis of their energy and time-of-flight. Using an experimental setup developed for measurements utilizing low-intensity (< 105 ions/s) radioactive beams, the fusion excitation functions for 16O + 12C and 18O + 12C have been measured. The fusion excitation function for 18O + 12C has been measured in the sub-barrier domain down to the 820 mub level, a factor of 30 lower than previous direct measurements. This measured fusion excitation function is compared to the predictions of a density constrained time-dependent Hartree-Fock model. This comparison reveals a shape difference in the fusion excitation functions, indicating a larger tunneling probability for the experimental data as compared to the theoretical calculations. In addition to the measured cross-section, the measured angular distribution of the evaporation residues provides insight into the relative importance of the different de-excitation channels. These evaporation residue angular distributions are compared to the predictions of a statistical model code, evapOR, revealing an under-prediction of the de-excitation channels associated with alpha particle emission.

  10. Neutron beam tests of CsI(Na) and CaF2(Eu) crystals for dark matter direct search

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    In recent decades, inorganic crystals have been widely used in dark matter direct search experiments. To contribute to the understanding of the capabilities of CsI(Na) and CaF2(Eu) crystals, a mono-energetic neutron beam is utilized to study the properties of nuclear recoils, which are expected to be similar to signals of dark matter direct detection. The quenching factor of nuclear recoils in CsI(Na) and CaF2Eu, as well as an improved discrimination factor between nuclear recoils and γ backgrounds in CsI(Na), are reported.

  11. Comparing neutron and X-ray-based dual beam gauges for characterising industrial organic-based materials.

    PubMed

    Bartle, C Murray; Kroger, Chris; West, John G

    2005-01-01

    Comparisons are made of the neutron gamma transmission (NEUGAT) and dual energy X-ray absorption (DEXA) methods of measuring the composition of organic-based industrial products. A simple model is developed to allow comparisons to be made particularly of the measurement precision and the industrial performance. These gauges have similar applications but the latter gauge is shown to be more suitable for high and variable product throughputs. X-ray tube source and detector combinations provide higher beam fluxes, superior imaging and require less bulky shielding.

  12. Advanced Neutron Source (ANS) Project progress report

    SciTech Connect

    McBee, M.R.; Chance, C.M. ); Selby, D.L.; Harrington, R.M.; Peretz, F.J. )

    1990-04-01

    This report discusses the following topics on the advanced neutron source: quality assurance (QA) program; reactor core development; fuel element specification; corrosion loop tests and analyses; thermal-hydraulic loop tests; reactor control concepts; critical and subcritical experiments; material data, structural tests, and analysis; cold source development; beam tube, guide, and instrument development; hot source development; neutron transport and shielding; I C research and development; facility concepts; design; and safety.

  13. Optimised k0-instrumental neutron activation method using the TRIGA MARK I IPR-R1 reactor at CDTN/CNEN, Belo Horizonte, Brazil

    NASA Astrophysics Data System (ADS)

    Menezes, M. Â. B. C.; Jaćimović, R.

    2006-08-01

    The Nuclear Technology Development Centre/Brazilian Commission for Nuclear Energy, CDTN/CNEN, is the only Brazilian Institution to apply the k0-standardisation method of instrumental neutron activation technique determining elements using its own nuclear reactor, TRIGA MARK I IPR-R1. After changes in the reactor core configuration, the reactor neutron flux distribution in typical irradiation channels had to be updated, as well as the parameters f and α, needed to apply the k0-method of neutron activation analysis. The neutron flux distribution in the rotary rack was evaluated through the specific count rate of 198Au and the parameters f and α, were determined in five selected channels applying the "Cd-ratio for multi-monitor" method, using a set of Al-(0.1%)Au and Zr (99.8%) monitors. Several reference materials were analysed, indicating the effectiveness of the improved method.

  14. Absolute calibration and beam reconstruction of MITO(a ground-based instrument in the millimetric region)

    NASA Astrophysics Data System (ADS)

    Savini, G.; Orlando, A.; Battistelli, E. S.; De Petris, M.; Lamagna, L.; Luzzi, G.; Palladino, E.

    2003-09-01

    An efficient sky data reconstruction derives from a precise characterization of the observing instrument. Here we describe the reconstruction of performances of a single-pixel 4-band photometer installed at MITO (Millimeter and Infrared Testagrigia Observatory) focal plane. The strategy of differential sky observations at millimeter wavelengths, by scanning the field of view at constant elevation wobbling the subreflector, induces a good knowledge of beam profile and beam-throw amplitude, allowing efficient data recovery. The problems that arise estimating the detectors throughput by drift scanning on planets are shown. Atmospheric transmission, monitored by skydip technique, is considered for deriving final responsivities for the 4 channels using planets as primary calibrators.

  15. Differential Die-Away Instrument: Report on Neutron Detector Recovery Performance and Proposed Improvements

    SciTech Connect

    Goodsell, Alison Victoria; Swinhoe, Martyn Thomas; Henzl, Vladimir; Ianakiev, Kiril Dimitrov; Iliev, Metodi; Rael, Carlos D.; Desimone, David J.

    2014-09-22

    Four helium-3 (3He) detector/preamplifier packages (¾”/KM200, DDSI/PDT-A111, DDA/PDT-A111, and DDA/PDT10A) were experimentally tested to determine the deadtime effects at different DT neutron generator output settings. At very high count rates, the ¾”/KM200 package performed best. At high count rates, the ¾”/KM200 and the DDSI/PDT-A111 packages performed very well, with the DDSI/PDT-A111 operating with slightly higher efficiency. All of the packages performed similarly at mid to low count rates. Proposed improvements include using a fast recovery LANL-made dual channel preamplifier, testing smaller diameter 3He tubes, and further investigating quench gases.

  16. A New Neutron Radiography / Tomography / Imaging Station DINGO at OPAL

    NASA Astrophysics Data System (ADS)

    Garbe, U.; Randall, T.; Hughes, C.; Davidson, G.; Pangelis, S.; Kennedy, S. J.

    A new neutron radiography / tomography / imaging instrument DINGO was built to support the area of neutron imaging research (neutron radiography/tomography) at ANSTO. The instrument is designed for an international user community and for routine quality control for defense, industrial, cultural heritage and archaeology applications. In the industrial field it provides a useful tool for studying cracking and defects in steel or other metals. The instrument construction was completed at the end of June 2013 and it is currently in the hot commissioning stage. The usable neutron flux is mainly determined by the neutron source, but it depends on the instrument position and the resolution. The instrument position for DINGO is the thermal neutron beam port HB-2 in the reactor hall. The measured flux (using gold foil) for an L/D of approximately 500 at HB-2 is 5.3*107 [n/cm2s], which is in a similar range to other facilities. A special feature of DINGO is the in-pile collimator position in front of the main shutter at HB-2. The collimator offers two pinholes with a possible L/D of 500 and 1000. A secondary collimator separates the two beams by blocking one and positions another aperture for the other beam. The whole instrument operates in two different positions, one for high resolution and one for high speed. In the current configuration DINGO measured first radiography and tomography data sets on friendly user test samples.

  17. Design of a high-current low-energy beam transport line for an intense D-T/D-D neutron generator

    NASA Astrophysics Data System (ADS)

    Lu, Xiaolong; Wang, Junrun; Zhang, Yu; Li, Jianyi; Xia, Li; Zhang, Jie; Ding, Yanyan; Jiang, Bing; Huang, Zhiwu; Ma, Zhanwen; Wei, Zheng; Qian, Xiangping; Xu, Dapeng; Lan, Changlin; Yao, Zeen

    2016-03-01

    An intense D-T/D-D neutron generator is currently being developed at the Lanzhou University. The Cockcroft-Walton accelerator, as a part of the neutron generator, will be used to accelerate and transport the high-current low-energy beam from the duoplasmatron ion source to the rotating target. The design of a high-current low-energy beam transport (LEBT) line and the dynamics simulations of the mixed beam were carried out using the TRACK code. The results illustrate that the designed beam line facilitates smooth transportation of a deuteron beam of 40 mA, and the number of undesired ions can be reduced effectively using two apertures.

  18. Thermal analysis and neutron production characteristics of a low power copper beam dump-cum-target for LEHIPA

    NASA Astrophysics Data System (ADS)

    Sawant, Y. S.; Thomas, R. G.; Verma, V.; Agarwal, A.; Prasad, N. K.; Bhagwat, P. V.; Saxena, A.; Singh, P.

    2016-01-01

    Monte Carlo simulations of heat deposition and neutron production have been carried out for the low power beam dump-cum-target for the 20 MeV Low Energy High Intensity Proton Accelerator (LEHIPA) facility at BARC using GEANT4 and FLUKA. Thermal analysis and heat transfer calculations have also been carried out using the computational fluid dynamics code CFD ACE+. In this work we present the details of the analysis of the low power beam dump-cum-target designed for conditioning of the accelerator upto a maximum power of 600 kW with a duty cycle of 2% which corresponds to an average power of 12 kW in the first phase.

  19. Theoretical study on production of heavy neutron-rich isotopes around the N = 126 shell closure in radioactive beam induced transfer reactions

    NASA Astrophysics Data System (ADS)

    Zhu, Long; Su, Jun; Xie, Wen-Jie; Zhang, Feng-Shou

    2017-04-01

    In order to produce more unknown neutron-rich nuclei around N = 126, the transfer reactions 136Xe + 198Pt, 136-144Xe + 208Pb, and 132Sn + 208Pb are investigated within the framework of the dinuclear system (DNS) model. The influence of neutron excess of projectile on production cross sections of target-like products is studied through the reactions 136,144Xe + 208Pb. We find that the radioactive projectile 144Xe with much larger neutron excess is favorable to produce neutron-rich nuclei with charge number less than the target rather than produce transtarget nuclei. The incident energy dependence of yield distributions of fragments in the reaction 132Sn + 208Pb are also studied. The production cross sections of neutron-rich nuclei with Z = 72- 77 are predicted in the reactions 136-144Xe + 208Pb and 132Sn + 208Pb. It is noticed that the production cross sections of unknown neutron-rich nuclei in the reaction 144Xe + 208Pb are at least two orders of magnitude larger than those in the reaction 136Xe + 208Pb. The radioactive beam induced transfer reactions 139,144Xe + 208Pb, considering beam intensities proposed in SPIRAL2 (Production System of Radioactive Ion and Acceleration On-Line) project as well, for production of neutron-rich nuclei around the N = 126 shell closure are investigated for the first time. It is found that, in comparison to the stable beam 136Xe, the radioactive beam 144Xe shows great advantages for producing neutron-rich nuclei with N = 126 and the advantages get more obvious for producing nuclei with less charge number.

  20. Instrumentation for Creation and Diagnostics of an Intense Cold Atom Beam: CW Atom Laser and Nanotube Single Atom Detector

    DTIC Science & Technology

    2007-02-14

    instrumentation for coherent optical information processing. This work was just published as the cover story of Nature, February 8, 2007 [ 2 ] and was...transmitted program ’Talk of the Nation: Science Friday’ (on February 9). For this setup, high-power DC Power supplies and high-laser-power acousto - optic ...introduced. Finally, the condensates are imaged with a laser beam (yellow), near resonance for the atoms’ F = 2 -- F = 3 transition, after optical

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

    SciTech Connect

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

    2016-01-15

    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 ∼10{sup 12}–10{sup 13} 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.

  2. 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.

  3. Analyses of the reflector tank, cold source, and beam tube cooling for ANS reactor. [Advanced Neutron Source (ANS)

    SciTech Connect

    Marland, S. )

    1992-07-01

    This report describes my work as an intern with Martin Marietta Energy Systems, Inc., in the summer of 1991. I was assigned to the Reactor Technology Engineering Department, working on the Advanced Neutron Source (ANS). My first project was to select and analyze sealing systems for the top of the diverter/reflector tank. This involved investigating various metal seals and calculating the forces necessary to maintain an adequate seal. The force calculations led to an analysis of several bolt patterns and lockring concepts that could be used to maintain a seal on the vessel. Another project involved some pressure vessel stress calculations and the calculation of the center of gravity for the cold source assembly. I also completed some sketches of possible cooling channel patterns for the inner vessel of the cold source. In addition, I worked on some thermal design analyses for the reflector tank and beam tubes, including heat transfer calculations and assisting in Patran and Pthermal analyses. To supplement the ANS work, I worked on other projects. I completed some stress/deflection analyses on several different beams. These analyses were done with the aid of CAASE, a beam-analysis software package. An additional project involved bending analysis on a carbon removal system. This study was done to find the deflection of a complex-shaped beam when loaded with a full waste can.

  4. Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Shin, Jae Won; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Min, Kyung Joo; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

    2015-10-01

    Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑ Φ(En) σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑ Φ(En) σ(En) along with other parameters in a neutron activation method.

  5. Thermoluminescence in CaF2:Dy and CaF2:Mn induced by monoenergetic, parallel beam, 81-0 meV diffracted neutrons.

    PubMed

    Horowitz, Y S; Shahar, B B; Dubi, A; Pinto, H

    1977-05-01

    The thermal neutron thermoluminescent response of CaF2 : Dy (TLD-200, 0-35% wt Dy) and CaF2 : mn (TLD-400, 2% wt Mn) has been measured by exposure to a monoenergetic, parallel beam of 81-0 meV neutrons from a Kandi-II diffractometer. The TL dosemeters were rectangular and of 0-165 X 0-165 X 0-83 cm dimensions. The measured integral TLD-200 response for a neutron fluence of 10(10) n cm-2 was 0-21 +/- 0-013 R of 60Co which translates to 0-33 +/- 0-021 R 60Co for a Maxwellian neutron energy distribution at T = 293-6 K. The measured integral TLD-400 response for a neutron fluence of 10(10) n cm-2 was 0-09 +/- 0-006 R 60Co which similarly translates to 0-14 +/- 0-010 R 60Co for a Maxwellian neutron energy distribution at T = 293-6 K. The thermoluminescent response of both materials is both theoretically and experimentally shown to be composed of a thermal neutron induced prompt gamma component (approximately 20%) as well as the major component due to the thermal neutron induced beta decay of 165Dy and 56Mn. It is pointed out that the thermal neutron thermoluminescent response of both materials is size and geometry dependent.

  6. Development and clinical research of the He-Ne laser medical instrument with quasi-single beam in two ways

    NASA Astrophysics Data System (ADS)

    Li, Xuehui; Zhang, Zhong; Chen, Peishan

    1996-09-01

    Much research has been made into low-powered He-Ne laser radiating treatment. Our He-Ne laser treating instrument can transmit double beams in two ways, which is quite different from the old-typed He-Ne laser instrument having one single beam in one way. The power of 250mm-laser totals 2.8mw-3. 5mw, nearing the theoretical value. The invention not only increases the laser radiating power, with convenient treatment of patients, but also eliminates the technical prejudice against radiating beams in one way. Since 1994, three two-way He-Ne laser instruments have been used in the clinical experiments on the ophthalmology in Dalian Railway Hospital. After concentrated treatment of the period of 3 winter and 3 summer vacations, 951 near-sighted eyes in 679 cases of near-sightedness of teenagers were treated. The recent total efficiency is 94.4 percent. The efficiency investigated after half a year is up to 60 percent.

  7. Modeling filters for formation of mono-energetic neutron beams in the research reactor IRT MEPhI and optimization of radiation shielding for liquid-xenon detector

    SciTech Connect

    Ivakhin, S. V.; Tikhomirov, G. V.; Bolozdynya, A. I.; Efremenko, Y. V.; Akimov, D. Y.; Stekhanov, V. N.

    2012-07-01

    The paper considers formation of mono-energetic neutron beams at the entrance of experimental channels in research reactors for various applications. The problem includes the following steps: 1. Full-scale mathematical model of the research IRT MEPhI was developed for numerical evaluations of neutron spectra and neutron spatial distribution in the area of experimental channels. 2. Modeling of filters in the channel to shift neutron spectrum towards the required mono-energetic line was performed. 3. Some characteristics of neutron beams at the entrance of detector were evaluated. The filter materials were selected. The calculations were carried out with application of the computer code based on the high-precision Monte-Carlo code MCNP. As a result, mathematical model was created for the filter which is able to form mono-energetic (24 keV) neutron beam. The study was carried out within the frames of the research project on development of Russian emission detector with liquid noble gas to observe rare processes of neutrino scattering and particles of hypothetical dark matter in atomic nuclei. (authors)

  8. The Advanced Neutron Source (ANS) project: A world-class research reactor facility

    SciTech Connect

    Thompson, P.B.; Meek, W.E.

    1993-07-01

    This paper provides an overview of the Advanced Neutron Source (ANS), a new research facility being designed at Oak Ridge National Laboratory. The facility is based on a 330 MW, heavy-water cooled and reflected reactor as the neutron source, with a thermal neutron flux of about 7.5{times}10{sup 19}m{sup {minus}2}{center_dot}sec{sup {minus}1}. Within the reflector region will be one hot source which will serve 2 hot neutron beam tubes, two cryogenic cold sources serving fourteen cold neutron beam tubes, two very cold beam tubes, and seven thermal neutron beam tubes. In addition there will be ten positions for materials irradiation experiments, five of them instrumented. The paper touches on the project status, safety concerns, cost estimates and scheduling, a description of the site, the reactor, and the arrangements of the facilities.

  9. Systematic neutron guide misalignment for an accelerator-driven spallation neutron source

    NASA Astrophysics Data System (ADS)

    Zendler, C.; Bentley, P. M.

    2016-08-01

    The European Spallation Source (ESS) is a long pulse spallation neutron source that is currently under construction in Lund, Sweden. A considerable fraction of the 22 planned instruments extend as far as 75-150 m from the source. In such long beam lines, misalignment between neutron guide segments can decrease the neutron transmission significantly. In addition to a random misalignment from installation tolerances, the ground on which ESS is built can be expected to sink with time, and thus shift the neutron guide segments further away from the ideal alignment axis in a systematic way. These systematic errors are correlated to the ground structure, position of buildings and shielding installation. Since the largest deformation is expected close to the target, even short instruments might be noticeably affected. In this study, the effect of this systematic misalignment on short and long ESS beam lines is analyzed, and a possible mitigation by overillumination of subsequent guide sections investigated.

  10. Neutron scattering at Australia's replacement research reactor

    NASA Astrophysics Data System (ADS)

    Robinson, R. A.; Kennedy, S. J.

    2002-01-01

    On August 25 1999, the Australian government gave final approval to build a research reactor to replace the existing HIFAR reactor at Lucas Heights. The replacement reactor, which will commence operation in 2005, will be multipurpose in function, with capabilities for both neutron-beam research and radioisotope production. Regarding beams, cold and thermal neutron sources are to be installed and the intent is to use supermirror guides, with coatings with critical angles up to 3 times that of natural Ni, to transport cold and thermal neutron beams into a large modern guide hall. The reactor and all the associated infrastructure, with the exception of the neutron beam instruments, is to be built by INVAP, SE and subcontractors in a turnkey contract. The goal is to have at least eight leading-edge neutron-beam instruments ready in 2005, and they will be developed by ANSTO and other contracted organisations, in consultation with the Australian user community and interested overseas parties. A review of the planned scientific capabilities, a description of the facility and a status report on the activities so far is given.

  11. Deformation of the very neutron-deficient rare-earth nuclei produced with the SPIRAL 76Kr radioactive beam and studied with EXOGAM + DIAMANT

    SciTech Connect

    Redon, N.; Guinet, D.; Lautesse, Ph.; Meyer, M.; Rosse, B.; Stezowski, O.; France, G. de; Casandjian, J. M.

    2004-02-27

    The structure of the very neutron-deficient rare-earth nuclei has been investigated in the first experiment with the EXOGAM gamma array coupled to the DIAMANT light charged particle detector using radioactive beam of 76Kr delivered by the SPIRAL facility. Very neutron-deficient Pr, Nd and Pm isotopes have been populated at rather high spin by the reaction 76Kr + 58Ni at a beam energy of 328 MeV. We report here the first results of this experiment.

  12. Accelerator systems and instrumentation for the NuMI neutrino beam

    SciTech Connect

    Zwaska, Robert Miles

    2005-12-01

    The neutrinos at the main injector (NuMI) neutrino beam facility began operating at the Fermi National Accelerator Laboratory in 2005. NuMI produces an intense, muon-neutrino beam to a number of experiments. Foremost of these experiments is MINOS-the Main Injector Neutrino Oscillation Search-that uses two neutrino detectors in the beam, one at Fermilab and one in northern Minnesota, to investigate the phenomenon of neutrino oscillations.

  13. Scattering correction algorithm for neutron radiography and tomography tested at facilities with different beam characteristics

    NASA Astrophysics Data System (ADS)

    Hassanein, René; de Beer, Frikkie; Kardjilov, Nikolay; Lehmann, Eberhard

    2006-11-01

    A precise quantitative analysis with the neutron radiography technique of materials with a high-neutron scattering cross section, imaged at small distances from the detector, is impossible if the scattering contribution from the investigated material onto the detector is not eliminated in the right way. Samples with a high-neutron scattering cross section, e.g. hydrogenous materials such as water, cause a significant scattering component in their radiographs. Background scattering, spectral effects and detector characteristics are identified as additional causes for disturbances. A scattering correction algorithm based on Monte Carlo simulations has been developed and implemented to take these effects into account. The corrected radiographs can be used for a subsequent tomographic reconstruction. From the results one can obtain quantitative information, in order to detect e.g. inhomogeneity patterns within materials, or to measure differences of the mass thickness in these materials. Within an IAEA-CRP collaboration the algorithms have been tested for applicability on results obtained at the South African SANRAD facility at Necsa, the Swiss NEUTRA facilities at PSI as well as the German CONRAD facility at HMI, all with different initial neutron spectra. Results of a set of dedicated neutron radiography experiments are being reported.

  14. Simulation of neutron displacement damage in bipolar junction transistors using high-energy heavy ion beams.

    SciTech Connect

    Doyle, Barney Lee; Buller, Daniel L.; Hjalmarson, Harold Paul; Fleming, Robert M; Bielejec, Edward Salvador; Vizkelethy, Gyorgy

    2006-12-01

    Electronic components such as bipolar junction transistors (BJTs) are damaged when they are exposed to radiation and, as a result, their performance can significantly degrade. In certain environments the radiation consists of short, high flux pulses of neutrons. Electronics components have traditionally been tested against short neutron pulses in pulsed nuclear reactors. These reactors are becoming less and less available; many of them were shut down permanently in the past few years. Therefore, new methods using radiation sources other than pulsed nuclear reactors needed to be developed. Neutrons affect semiconductors such as Si by causing atomic displacements of Si atoms. The recoiled Si atom creates a collision cascade which leads to displacements in Si. Since heavy ions create similar cascades in Si we can use them to create similar damage to what neutrons create. This LDRD successfully developed a new technique using easily available particle accelerators to provide an alternative to pulsed nuclear reactors to study the displacement damage and subsequent transient annealing that occurs in various transistor devices and potentially qualify them against radiation effects caused by pulsed neutrons.

  15. Los Alamos Neutron Science Center (LANSCE) Nuclear Science Facilities

    SciTech Connect

    Nelson, Ronald Owen; Wender, Steve

    2015-06-19

    The Los Alamos Neutron Science Center (LANSCE) facilities for Nuclear Science consist of a high-energy "white" neutron source (Target 4) with 6 flight paths, three low-energy nuclear science flight paths at the Lujan Center, and a proton reaction area. The neutron beams produced at the Target 4 complement those produced at the Lujan Center because they are of much higher energy and have shorter pulse widths. The neutron sources are driven by the 800-MeV proton beam of the LANSCE linear accelerator. With these facilities, LANSCE is able to deliver neutrons with energies ranging from a milli-electron volt to several hundreds of MeV, as well as proton beams with a wide range of energy, time and intensity characteristics. The facilities, instruments and research programs are described briefly.

  16. Characterization of Infrared Diode Laser Beams and Atmospheric CO Imaging Instrument

    NASA Technical Reports Server (NTRS)

    Miles, Jonathan J.

    1999-01-01

    quantities of CO to provide a means for system characterization. Two related research efforts were undertaken during the term of the study reported here - continued development of an atmospheric CO imaging instrument and characterization of diode-laser beams. Both efforts were successful and are described within the body of this report. A second objective was to provide a means for undergraduate ISAT majors to become involved with the research described, to be afforded the opportunity to learn the technologies associated with the work performed. Two ISAT students gained a comprehensive understanding and interest in missions supported by NASA through direct involvement in this project. Many more students were exposed to these technologies through demonstrations, laboratory tours, and explanations provided in lectures.

  17. Instrument for spatially resolved simultaneous measurements of forces and currents in particle beams

    SciTech Connect

    Spethmann, A. Trottenberg, T. Kersten, H.

    2015-01-15

    The article presents a device for spatially resolved and simultaneous measurements of forces and currents in particle beams, especially in beams composed of ions and neutral atoms. The forces are exerted by the impinging beam particles on a plane circular conductive target plate of 20 mm diameter mounted on a pendulum with electromagnetic force compensation. The force measurement in the micronewton range is achieved by electromagnetic compensation by means of static Helmholtz coils and permanent magnets attached to the pendulum. Exemplary measurements are performed in the 1.2 keV beam of a broad beam ion source. The simultaneous measurements of forces and currents onto the same target are compared with each other and with Faraday cup measurements.

  18. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    PubMed

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors.

  19. Trace elements determinations in cancerous and non-cancerous human tissues using instrumental neutron activation analysis

    SciTech Connect

    Choi, Insup.

    1989-01-01

    Recent improvements in analyzing techniques when coupled to the growing knowledge of trace element biochemistry provide a powerful tool to investigate the relationship between trace elements and cancer. It is hoped that selective delivery or restriction of specific minerals may aid in cancer prevention or treatment. Tissues were collected at the time of surgery of various cancer patients including colon cancer and breast cancer. Three kinds of tissues were taken from a patient; cancerous, noncancerous, and transitional tissue obtained from a region located between the cancer and healthy tissues. A total of 57 tissues were obtained from 19 cancer patients. Seven of them were colon cancer patients, and 5 of them were breast cancer patients. Nine elements were determined using instrumental activation analysis. Cancerous colon tissue had significantly higher concentrations of selenium and iron than healthy tissues. Cancerous breast tissue had significantly higher concentrations of selenium, iron, manganese, and rubidium than healthy tissues. Iron can be enriched in cancer tissue because cancer tissue retains more blood vessels. Selenium is enriched in cancer tissue, possibly in an effort of the body to inhibit the growth of tumors. The manganese enrichment can be explained in the same manner as selenium considering its suspected anticarcinogenicity. It is not certain why rubidium was enriched in cancer tissue. It could be that this is the result of alteration of cell membrane permeability, change in extracellular matrix, or increased metabolism in cancer tissue.

  20. Neutron detectors at IPNS

    SciTech Connect

    Crawford, R.K.; Haumann, J.R.; Ostrowski, G.E.

    1990-01-01

    The heart of each time-of-flight neutron scattering instrument is its complement of detectors and the associated encoding and counting electronics. Currently there are ten fully-scheduled neutron scattering instruments in operation at IPNS, with three more instruments under development. Six of these instruments use position-sensitive neutron detectors (PSDs) of various types. These PSDs include a 30 cm {times} 30 cm, {approximately}3 mm resolution, neutron Anger camera area PSD with {sup 6}Li-glass scintillator; a 2.5 cm dia, {approximately}0.7 mm resolution, microchannel-plate area PSD with {sup 6}Li-glass scintillator; a 20 cm {times} 20 cm, {approximately}5 mm resolution, {sup 3}He proportional counter area PSD; a 40 cm {times} 40 cm, {approximately}4 mm resolution, {sup 3}He proportional counter area PSD; a flat 25 cm long, {approximately}1.6 mm resolution, {sup 3}He proportional counter linear PSD; and 160 cylindrical {sup 3}He proportional counter linear PSDs, each of which is 1.27 cm in dia and 60 cm long and has {approximately}14 mm resolution. In addition to these PSDs, {approximately}750 standard cylindrical {sup 3}He proportional counters of various sizes are utilized on IPNS instruments, and {approximately}20 BF{sub 3} pulsed ion chambers are in use as beam monitors. This paper discusses these various detectors and associated electronics, with emphasis on the instrumental specifications and the reasons for the selection of the different types of detectors. Observed performance of these detectors is also discussed. 19 refs., 5 figs., 2 tabs.

  1. Determination of airborne cadmium in environmental tobacco smoke by instrumental neutron activation analysis with a compton suppression system.

    PubMed

    Landsberger, S; Larson, S; Wu, D

    1993-06-01

    Concentrations of cadmium, a toxic trace element, were measured in the indoor air of several public places where environmental tobacco smoke was present. Particulate-phase cadmium concentrations were determined by analyzing air filter samples using epithermal instrumental neutron activation analysis in conjunction with a Compton suppression gamma-ray detection system, in which the detection limit for cadmium was reduced to a few nanograms per filter. A cascade impactor and a personal filter sampler were used to collect the indoor suspended particulate matter for size-fractionated mass as well as total mass, respectively. Results show that where environmental tobacco smoke is present, cadmium concentrations are significantly higher than background and that about 80% of the cadmium found in indoor airborne particulate matter is associated with particles with aerodynamic diameters less than 1.8 microns. In one instance, airborne cadmium concentrations in a music club were found to be 38 ng/m, which is at least 30 times higher than background.

  2. Compartmentalization of trace elements in guinea pig tissues by INAA (instrumental neutron activation analysis) and AAS (atomic absorption spectroscopy)

    SciTech Connect

    Chatt, A.; Holzbecher, J.; Katz, S.A.

    1988-01-01

    Human scalp hair analysis has received considerable attention from a variety of disciplines over the last 20 yr or so. Trace element levels of hair have been used in environmental, epidemiological, forensic, nutritional, predictive, and preventive medicine studies. There still exist confusion, skepticism, and controversy, however, among the experts as well as lay persons in the interpretation of hair trace element data. Much of the criticism stems from the lack of quantitative and reliable data on the ability of hair to accurately reflect dose-response relationships. To better define the significance or hair trace element levels (under the auspices of the International Atomic Energy Agency), the authors have undertaken a controlled set of animal experiments in which trace element levels in hair and other tissues have been measured after a mild state of systemic intoxication by chronic, low-does exposure to cadmium and selenium. Instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) methods have been developed for the determination of several elements with a high degree of precision and accuracy.

  3. Neutron depth profiling: Overview and description of NIST facilities

    SciTech Connect

    Downing, R.G.; Lamaze, G.P.; Langland, J.K.; Hwang, S.T.

    1993-01-01

    The Cold Neutron Depth Profiling (CNDP) instrument at the NIST Cold Neutron Research Facility (CNRF) is now operational. The neutron beam originates from a 16 L D2O ice cold source and passes through a filter of 135 mm of single crystal sapphire. The neutron energy spectrum may be described by a 65 K Maxwellian distribution. The sample chamber configuration allows for remote controlled scanning of 150 x 150 mm sample areas including the varying of both sample and detector angle. The improved sensitivity over the current thermal depth profiling instrument has permitted the first nondestructive measurements of (17)O profiles. The paper describes the CNDP instrument, illustrates the neutron depth profiling (NDP) technique with examples, and gives a separate bibliography of NDP publications.

  4. Neutron Depth Profiling: Overview and Description of NIST Facilities.

    PubMed

    Downing, R G; Lamaze, G P; Langland, J K; Hwang, S T

    1993-01-01

    The Cold Neutron Depth Profiling (CNDP) instrument at the NIST Cold Neutron Research Facility (CNRF) is now operational. The neutron beam originates from a 16 L D2O ice cold source and passes through a filter of 135 mm of single crystal sapphire. The neutron energy spectrum may be described by a 65 K Maxwellian distribution. The sample chamber configuration allows for remote controlled scanning of 150 × 150 mm sample areas including the varying of both sample and detector angle. The improved sensitivity over the current thermal depth profiling instrument has permitted the first nondestructive measurements of (17)O profiles. This paper describes the CNDP instrument, illustrates the neutron depth profiling (NDP) technique with examples, and gives a separate bibliography of NDP publications.

  5. Neutron Depth Profiling: Overview and Description of NIST Facilities

    PubMed Central

    Downing, R. G.; Lamaze, G. P.; Langland, J. K.; Hwang, S. T.

    1993-01-01

    The Cold Neutron Depth Profiling (CNDP) instrument at the NIST Cold Neutron Research Facility (CNRF) is now operational. The neutron beam originates from a 16 L D2O ice cold source and passes through a filter of 135 mm of single crystal sapphire. The neutron energy spectrum may be described by a 65 K Maxwellian distribution. The sample chamber configuration allows for remote controlled scanning of 150 × 150 mm sample areas including the varying of both sample and detector angle. The improved sensitivity over the current thermal depth profiling instrument has permitted the first nondestructive measurements of 17O profiles. This paper describes the CNDP instrument, illustrates the neutron depth profiling (NDP) technique with examples, and gives a separate bibliography of NDP publications. PMID:28053461

  6. Beam Steering Mechanism for EarthCARE Atmospheric Lidar Instrument- An Improved Piezoelectic Tip-Tilt Mechanism

    NASA Astrophysics Data System (ADS)

    Bourgain, Frederic; Sosnicki, Olivier; Barillot, Francois; Claeyssen, Frank; Lelay, Jean Pierre; Prevost, Eddie; Pain, Thierry; Germain, Benoit

    2013-09-01

    In the context of the ATLID instrument [1] embedded in the EarthCARE mission (Earth Cloud, Aerosol and Radiation Explorer), a Beam Steering Assembly is deviating a pulsed high energy UV laser beam to compensate the pointing misalignment between the emission and reception paths of ATLID with a very high stability and high resolution.Within the EarthCARE mission, led by ESA, Astrium is responsible for the ATLID instrument. The BSA development, manufacture and tests were assigned by Astrium to Sodern, an EADS filial.In this context, Cedrat Technologies was sub-contracted by Sodern to design, manufacture and test the performances of Beam Steering Mechanism flights models.This paper points out the main mechanism design issues:• High performances;• Mechanical and thermal stability;• Low power consumption;• High integration level;• High reliability and safety;• Cleanliness requirements.and examines how these issues have been approached by Cedrat Technologies and Sodern. Test results are reported when available.

  7. Optimization of the beam shaping assembly in the D-D neutron generators-based BNCT using the response matrix method.

    PubMed

    Kasesaz, Y; Khalafi, H; Rahmani, F

    2013-12-01

    Optimization of the Beam Shaping Assembly (BSA) has been performed using the MCNP4C Monte Carlo code to shape the 2.45 MeV neutrons that are produced in the D-D neutron generator. Optimal design of the BSA has been chosen by considering in-air figures of merit (FOM) which consists of 70 cm Fluental as a moderator, 30 cm Pb as a reflector, 2mm (6)Li as a thermal neutron filter and 2mm Pb as a gamma filter. The neutron beam can be evaluated by in-phantom parameters, from which therapeutic gain can be derived. Direct evaluation of both set of FOMs (in-air and in-phantom) is very time consuming. In this paper a Response Matrix (RM) method has been suggested to reduce the computing time. This method is based on considering the neutron spectrum at the beam exit and calculating contribution of various dose components in phantom to calculate the Response Matrix. Results show good agreement between direct calculation and the RM method.

  8. Polarized neutrons for Australian scientific research

    NASA Astrophysics Data System (ADS)

    Kennedy, Shane J.

    2005-02-01

    Polarized neutron scattering has been a feature at ANSTO's HIFAR research reactor since the first polarization analysis (PA) spectrometer Longpol began operation over 30 years ago. Since that time, we have improved performance of Longpol and added new capabilities in several reincarnations of the instrument. Most of the polarized neutron experiments have been in the fields of magnetism and superconductivity, and most of that research has involved PA. Now as we plan our next generation neutron beam facility, at the Replacement Research Reactor (RRR), we intend to continue the tradition of PA but with a far broader scope in mind. Our new capabilities will combine PA and energy analysis with both cold and thermal neutron source spectra. We will also provide capabilities for research with polarized neutrons in small-angle neutron scattering and in neutron reflectometry. The discussion includes a brief historical account of the technical developments with a summary of past and present applications of polarized neutrons at HIFAR, and an outline of the polarized neutron capabilities that will be included in the first suite of instruments, which will begin operation at the new reactor in 2006.

  9. The plain truth about forming a plane wave of neutrons

    NASA Astrophysics Data System (ADS)

    Wagh, Apoorva G.; Abbas, Sohrab; Treimer, Wolfgang

    2011-04-01

    We have attained the first sub-arcsecond collimation of a monochromatic neutron beam by diffracting neutrons from a Bragg prism, viz. a single crystal prism operating in the vicinity of Bragg incidence. Analytical as well numerical computations based on the dynamical diffraction theory, led to the optimised collimator configuration of a silicon {1 1 1} Bragg prism for 5.26 Å neutrons. We fabricated a Bragg prism to these specifications, tested and operated it at the double diffractometer setup in Helmholtz Zentrum Berlin to produce a 0.58 arcsec wide monochromatic neutron beam. With a similarly optimised Bragg prism analyser of opposite asymmetry, we recorded a 0.62 arcsec wide virgin rocking curve for this ultra-parallel beam. With this nearly plane-wave neutron beam, we have recorded the first ever USANS spectrum in Q˜10-6 Å-1 range with a hydroxyapatite casein protein sample and demonstrated the instrument capability to characterise agglomerates up to 150 μm in size. The super-collimated monochromatic beam has also enabled us to record the first neutron diffraction pattern from a macroscopic grating of 200 μm period. The transverse coherence length of 175 μm (FWHM) of the ultra-parallel beam derived from the analysis of this pattern, is the greatest achieved to date for Å wavelength neutrons.

  10. New instruments at the upgraded JRR-3 reactor

    NASA Astrophysics Data System (ADS)

    Funahashi, Satoru

    1991-10-01

    A new JRR-3 reactor equipped with a liquid hydrogen cold source started to operate at 20 MW full power for general users in November 1990. The reactor provides seven horizontal beam holes in the reactor room and three cold guides and two thermal ones in the guide hall. In total about twenty five instruments are planned for use with the neutron beam. Eight triple-axis neutron spectrometers, two small-angle scattering machines, two high-resolution powder diffractometers, two radiography instruments are included among these. More than half of them have already been completed and the rest will be installed in the next two years.

  11. Measuring the Noble Metal and Iodine Composition of Extracted Noble Metal Phase from Spent Nuclear Fuel Using Instrumental Neutron Activation Analysis

    SciTech Connect

    Palomares, R. I.; Dayman, Kenneth J.; Landsberger, Sheldon; Biegalski, Steven R.; Soderquist, Chuck Z.; Casella, Amanda J.; Brady Raap, Michaele C.; Schwantes, Jon M.

    2015-04-01

    Mass quantities of noble metal and iodine nuclides in the metallic noble metal phase extracted from spent fuel are measured using instrumental neutron activation analysis (NAA). Nuclide presence is predicted using fission yield analysis, and mass quantification is derived from standard gamma spectroscopy and radionuclide decay analysis. The nuclide compositions of noble metal phase derived from two dissolution methods, UO2 fuel dissolved in nitric acid and UO2 fuel dissolved in ammonium-carbonate and hydrogen-peroxide solution, are compared. Lastly, the implications of the rapid analytic speed of instrumental NAA are discussed in relation to potential nuclear forensics applications.

  12. Simulation of a suite of generic long-pulse neutron instruments to optimize the time structure of the European Spallation Source

    SciTech Connect

    Lefmann, Kim; Kleno, Kaspar H.; Holm, Sonja L.; Sales, Morten; Birk, Jonas Okkels; Hansen, Britt R.; Knudsen, Erik; Willendrup, Peter K.; Lieutenant, Klaus; Moos, Lars von; Andersen, Ken H.

    2013-05-15

    We here describe the result of simulations of 15 generic neutron instruments for the long-pulsed European Spallation Source. All instruments have been simulated for 20 different settings of the source time structure, corresponding to pulse lengths between 1 ms and 2 ms; and repetition frequencies between 10 Hz and 25 Hz. The relative change in performance with time structure is given for each instrument, and an unweighted average is calculated. The performance of the instrument suite is proportional to (a) the peak flux and (b) the duty cycle to a power of approximately 0.3. This information is an important input to determining the best accelerator parameters. In addition, we find that in our simple guide systems, most neutrons reaching the sample originate from the central 3-5 cm of the moderator. This result can be used as an input in later optimization of the moderator design. We discuss the relevance and validity of defining a single figure-of-merit for a full facility and compare with evaluations of the individual instrument classes.

  13. Biases caused by the instrument bandwidth and beam width on simulated brightness temperature measurements from scanning microwave radiometers

    NASA Astrophysics Data System (ADS)

    Meunier, V.; Löhnert, U.; Kollias, P.; Crewell, S.

    2012-11-01

    More so than the traditional fixed radiometers, the scanning radiometer requires a careful design to ensure high quality measurements. Here the impact of the radiometer characteristics (e.g. antenna beam width, receiver bandwidth) and atmospheric propagation (e.g. curvature of the earth and refractivity) on the scanning radiometer measurements are presented. A forward radiative transfer model that includes all these effects to represent the instrument measurements is used to estimate the biases as differences between the measurement with and without these characteristics for three commonly used frequency bands: K, V and W-band. The receiver channel bandwidth errors are not so important in K-band and W-band. Thus, the use of a wider bandwidth to improve detection at low signal-to-noise conditions is acceptable. The impact of the antenna beam width is higher than the receiver bandwidth, but, for V-band where they are of similar importance. Using simple regression algorithms, the effects of the bandwidth and beam width biases in liquid water path, integrated water vapor, and temperature are also examined. The largest errors in liquid water path and integrated water vapor are associated with the beam width errors.

  14. Biases caused by the instrument bandwidth and beam width on simulated brightness temperature measurements from scanning microwave radiometers

    NASA Astrophysics Data System (ADS)

    Meunier, V.; Löhnert, U.; Kollias, P.; Crewell, S.

    2013-05-01

    More so than the traditional fixed radiometers, the scanning radiometer requires a careful design to ensure high quality measurements. Here the impact of the radiometer characteristics (e.g., antenna beam width and receiver bandwidth) and atmospheric propagation (e.g. curvature of the Earth and vertical gradient of refractive index) on scanning radiometer measurements are presented. A forward radiative transfer model that includes all these effects to represent the instrument measurements is used to estimate the biases. These biases are estimated using differences between the measurement with and without these characteristics for three commonly used frequency bands: K, V and W-band. The receiver channel bandwidth errors are less important in K-band and W-band. Thus, the use of a wider bandwidth to improve detection at low signal-to-noise conditions is acceptable at these frequencies. The biases caused by omitting the antenna beam width in measurement simulations are larger than those caused by omitting the receiver bandwidth, except for V-band where the bandwidth may be more important in the vicinity of absorption peaks. Using simple regression algorithms, the effects of the bandwidth and beam width biases in liquid water path, integrated water vapour, and temperature are also examined. The largest errors in liquid water path and integrated water vapour are associated with the beam width errors.

  15. Dense Plasma Focus as Collimated Source of D-D Fusion Neutron Beams for Irradiation Experiences and Study of Emitted Radiations

    NASA Astrophysics Data System (ADS)

    Milanese, M.; Niedbalski, J.; Moroso, R.; Guichón, S.; Supán, J.

    2008-04-01

    A "table-top" 2 kJ, 250 kA plasma focus, the PACO (Plasma AutoConfinado), designed by the Dense Plasma Group of IFAS is used in its optimum regime for neutron yield for obtaining collimated pulsed neutron beams (100 ns). A simple and low-cost shielding arrangement was developed in order to fully eliminate the 2.45 MeV neutrons generated in the PACO device (108 per shot at 31 kV, 1-2 mbar). Conventional neutron diagnostics: scintillator-photomultiplier (S-PMT), silver activation counters (SAC), etc., are used to determine the minimum width of the shielding walls. Emission of very hard electromagnetic pulses is also studied. Collimation using lead and copper plates is made to determine the localization of the very hard X-ray source. The maximum energy of the continuum photon distribution is estimated in 0,6 MeV using a system of filters.

  16. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel – design concept and experimental demonstration

    DOE PAGES

    Henzlova, Daniela; Menlove, Howard Olsen; Rael, Carlos D.; ...

    2015-10-09

    Our paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. We describe the initial feasibility demonstration of the CIPN instrument, which involved measurements of fourmore » pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. Lastly, these features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.« less

  17. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel-Design concept and experimental demonstration

    NASA Astrophysics Data System (ADS)

    Henzlova, D.; Menlove, H. O.; Rael, C. D.; Trellue, H. R.; Tobin, S. J.; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

    2016-01-01

    This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. These features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

  18. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel – design concept and experimental demonstration

    SciTech Connect

    Henzlova, Daniela; Menlove, Howard Olsen; Rael, Carlos D.; Trellue, Holly Renee; Tobin, Stephen Joseph; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

    2015-10-09

    Our paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. We describe the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. Lastly, these features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

  19. Status of the advanced neutron source. [Advanced Neutron Source Reactor

    SciTech Connect

    Hayter, J.B.

    1990-01-01

    Research reactors in the United States are becoming more and more outdated, at a time when neutron scattering is being recognized as an increasingly important technique in areas vital to the US scientific and technological future. The last US research reactor was constructed over 25 years ago, whereas new facilities have been built or are under construction in Japan, Russia and, especially, Western Europe, which now has a commanding lead in this important field. Concern over this situation in the early 1980's by a number of organizations, including the National Academy of Sciences, led to a recommendation that design work start urgently on an advanced US neutron research facility. This recommendation is realized in the Advanced Neutron Source Project. The centerpiece of the Advanced Neutron Source will be a new research reactor of unprecedented flux (>7.5 {times} 10{sup 19} m{sup {minus}2}{center dot}s{sup {minus}1}), equipped with a wide variety of state-of-the-art spectrometers and diffractometers on hot, thermal, and cold neutron beams. Very cold and ultracold neutron beams will also be provided for specialized experiments. This paper will discuss the current status of the design and the plans for scattering instrumentation. 5 refs.

  20. First in-beam γ -ray study of the level structure of neutron-rich 39S

    NASA Astrophysics Data System (ADS)

    Chapman, R.; Wang, Z. M.; Bouhelal, M.; Haas, F.; Liang, X.; Azaiez, F.; Behera, B. R.; Burns, M.; Caurier, E.; Corradi, L.; Curien, D.; Deacon, A. N.; Dombrádi, Zs.; Farnea, E.; Fioretto, E.; Gadea, A.; Hodsdon, A.; Ibrahim, F.; Jungclaus, A.; Keyes, K.; Kumar, V.; Lunardi, S.; Mǎrginean, N.; Montagnoli, G.; Napoli, D. R.; Nowacki, F.; Ollier, J.; O'Donnell, D.; Papenberg, A.; Pollarolo, G.; Salsac, M.-D.; Scarlassara, F.; Smith, J. F.; Spohr, K. M.; Stanoiu, M.; Stefanini, A. M.; Szilner, S.; Trotta, M.; Verney, D.

    2016-08-01

    The neutron-rich 39S nucleus has been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of 36S ions with a thin 208Pb target. The magnetic spectrometer, PRISMA, and the γ -ray array, CLARA, were used in the measurements. Gamma-ray transitions of the following energies were observed: 339, 398, 466, 705, 1517, 1656, and 1724 keV. Five of the observed transitions have been tentatively assigned to the decay of excited states with spins up to (11 /2- ). The results of a state-of-the-art shell-model calculation of the level scheme of 39S using the SDPF-U effective interaction are also presented. The systematic behavior of the excitation energy of the first 11 /2- states in the odd-A isotopes of sulfur and argon is discussed in relation to the excitation energy of the first excited 2+ states of the adjacent even-A isotopes. The states of 39S that have the components in their wave functions corresponding to three neutrons in the 1 f7 /2 orbital outside the N =20 core have also been discussed within the context of the 0 ℏ ω shell-model calculations presented here.