WorldWideScience

Sample records for neutrons target considerations

  1. Materials considerations in accelerator targets

    Science.gov (United States)

    Peacock, H. B.; Iyer, N. C.; Louthan, M. R.

    1995-09-01

    Future nuclear materials production and/or the burn-up of long lived radioisotopes may be accomplished through the capture of spallation produced neutrons in accelerators. Aluminum clad-lead and/or lead alloys has been proposed as a spallation target. Aluminum was the cladding choice because of the low neutron absorption cross section, fast radioactivity decay, high thermal conductivity, and excellent fabricability. Metallic lead and lead oxide powders were considered for the target core with the fabrication options being casting or powder metallurgy (PM). Scoping tests to evaluate gravity casting, squeeze casting, and casting and swaging processes showed that, based on fabricability and heat transfer considerations, squeeze casting was the preferred option for manufacture of targets with initial core cladding contact. Thousands of aluminum clad aluminum-lithium alloy core targets and control rods for tritium production have been fabricated by coextrusion processes and successfully irradiated in the SRS reactors. Tritium retention in, and release from, the coextruded product was modeled from experimental and operational data. The model assumed that tritium atoms, formed by the 6Li(n,a)3He reaction, were produced in solid solution in the Al-Li alloy. Because of the low solubility of hydrogen isotopes in aluminum alloys, the irradiated Al-Li rapidly became supersaturated in tritium. Newly produced tritium atoms were trapped by lithium atoms to form a lithium tritide. The effective tritium pressure required for trap or tritide stability was the equilibrium decomposition pressure of tritium over a lithium tritide-aluminum mixture. The temperature dependence of tritium release was determined by the permeability of the cladding to tritium and the local equilibrium at the trap sites. The model can be used to calculate tritium release from aluminum clad, aluminum-lithium alloy targets during postulated accelerator operational and accident conditions. This paper describes

  2. High power neutron production targets

    Energy Technology Data Exchange (ETDEWEB)

    Wender, S. [Los Alamos National Lab., NM (United States)

    1996-06-01

    The author describes issues of concern in the design of targets and associated systems for high power neutron production facilities. The facilities include uses for neutron scattering, accelerator driven transmutation, accelerator production of tritium, short pulse spallation sources, and long pulse spallation sources. Each of these applications requires a source with different design needs and consequently different implementation in practise.

  3. Neutron effects in humans: protection considerations

    Energy Technology Data Exchange (ETDEWEB)

    Fry, R.J.M.

    1985-01-01

    Committee I of the International Commission on Radiological Protection has recommended that the Quality Factor for neutrons should be changed from 10 to 20. This article is an interesting recount of the tale of Q from the viewpoint of an observer which illustrates many of the problems that the selection of protection standards pose. 32 refs., 5 tabs.

  4. Delayed neutrons measurement at the MEGAPIE target

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, S.; Bokov, P.; Dore, D.; Letourneau, A.; Prevost, A.; Ridikas, D. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA/SPhN), 91- Gif sur Yvette (France); Ledoux, X. [CEA Bruyeres-le-Chatel (CEA DIF, DPTA/SPN), 91 (France). Dept. de Physique Theorique et Appliquee

    2008-07-01

    In the framework of the Neutronic and Nuclear Assessment Task Group of the MEGAPIE experiment we measured the delayed neutron (DN) flux at the top of the target. The measurement was proposed mainly for radioprotection purposes since the DN flux at the top of the target has been estimated to be of the same order of magnitude as the prompt neutron flux. Given the strong model-dependence of DN predictions, the measurement of DN contribution to the total neutron activity at the top of the target was thus desired. Moreover, this measurement is complementary to the DN experiments performed at PNPI (Gatchina) on solid lead and bismuth targets. The DN measurement at MEGAPIE was performed during the start-up phase of the target. In this paper we present a detailed description of the experimental setup and some preliminary results on decay spectra. (authors)

  5. Delayed neutrons measurement at the MEGAPIE target

    CERN Document Server

    Panebianco, Stefano; Dore, Diane; Ledoux, Xavier; Letourneau, Alain; Prevost, Aurelien; Ridikas, Danas

    2007-01-01

    In the framework of the Neutronic and Nuclear Assessment Task Group of the MEGAPIE experiment we measured the delayed neutron (DN) flux at the top of the target. The measurement was proposed mainly for radioprotection purposes since the DN flux at the top of the target has been estimated to be of the same order of magnitude as the prompt neutron flux. Given the strong model-dependence of DN predictions, the measurement of DN contribution to the total neutron activity at the top of the target was thus desired. Moreover, this measurement is complementary to the DN experiments performed at PNPI (Gatchina) on solid lead and bismuth targets. The DN measurement at MEGAPIE was performed during the start-up phase of the target. In this paper we present a detailed description of the experimental setup and some preliminary results on decay spectra.

  6. Neutronic Characterization of the Megapie Target

    CERN Document Server

    Panebianco, Stefano; Bokov, Pavel; Chabod, Sebastien; Chartier, Frederic; Dupont, Emmeric; Dore, Diane; Ledoux, Xavier; Letourneau, Alain; Oriol, Ludovic; Prevost, Aurelien; Ridikas, Danas; Toussaint, Jean-Christian

    2007-01-01

    The MEGAPIE project is one of the key experiments towards the feasibility of Accelerator Driven Systems. On-line operation and post-irradiation analysis will provide the scientific community with unique data on the behavior of a liquid spallation target under realistic irradiation conditions. A good neutronics performance of such a target is of primary importance towards an intense neutron source, where an extended liquid metal loop requires some dedicated verifications related to the delayed neutron activity of the irradiated PbBi. In this paper we report on the experimental characterization of the MEGAPIE neutronics in terms of the prompt neutron (PN) flux inside the target and the delayed neutron (DN) flux on the top of it. For the PN measurements, a complex detector, made of 8 microscopic fission chambers, has been built and installed in the central part of the target to measure the absolute neutron flux and its spatial distribution. Moreover, integral information on the neutron energy distribution as a f...

  7. Neutronic characterization of the MEGAPIE target

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, Stefano [CEA, Irfu, Centre de Saclay, F-91191 Gif-sur-Yvette (France)], E-mail: Stefano.panebianco@cea.fr; Berg, Klara [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); David, Jean-Christophe [CEA, Irfu, Centre de Saclay, F-91191 Gif-sur-Yvette (France); Eid, Mohamed [CEA/DEN/DM2S/SERMA, Centre de Saclay, F-91194 Gif-sur-Yvette (France); Filges, Uwe; Groeschel, Friedrich [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Guertin, Arnaud [SUBATECH, Ecole des Mines, F-44307 Nantes (France); Konobeyev, Alexander Yu [Forschungszentrum Karlsruhe, IRS, D-76021 Karlsruhe (Germany); Latge, Christian [CEA/DEN/DTN/DIR, Centre de Cadarache, F-13108 Saint-Paul-lez-Durance (France); Lemaire, Sebastien [CEA, DAM Ile de France, F-91297 Bruyeres le Chatel (France); Leray, Sylvie; Letourneau, Alain [CEA, Irfu, Centre de Saclay, F-91191 Gif-sur-Yvette (France); Luethy, Markus [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Michel-Sendis, Franco [CEA, Irfu, Centre de Saclay, F-91191 Gif-sur-Yvette (France); Scazzi, Selene [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Stankunas, Gediminas [CEA, Irfu, Centre de Saclay, F-91191 Gif-sur-Yvette (France); Thiolliere, Nicolas [SUBATECH, Ecole des Mines, F-44307 Nantes (France); Tobler, Leonhard; Zanini, Luca [Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

    2009-04-15

    The MEGAPIE project aimed to design, build and operate a liquid metal spallation neutron target of about 1 MW beam power in the SINQ facility at the Paul Scherrer Institut (Villigen, Switzerland). This project is an important step in the roadmap towards the demonstration of the accelerator driven system (ADS) concept and high power liquid metal targets in general. Following the design phase, an experimental program was defined to provide a complete characterization of the facility by performing a 'mapping' of the neutron flux at different points, from the center of the target to the beam lines. The neutronic performance of the target was studied using different experimental techniques with the goals of validating the Monte Carlo codes used in the design of the target; additionally, the performance was compared with the solid lead targets used before and after the MEGAPIE experiment.

  8. Neutronic characterization of the MEGAPIE target

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, Stefano; David, Jean-Christophe; Leray, Sylvie; Letourneau, Alain; Michel-Sendis, Franco; Stankunas, Gediminas [CEA/IRFU, Gif-sur-Yvette (France); Berg, Klara; Filges, Uwe; Groeschel, Friedrich; Luethy, Markus; Scazzi, Selene; Tobler, Leonhard; Zanini, Luca [PSI, Villigen (Switzerland); Eid, Mohamed [CEA/DEN/DM2S/SERMA, Gif-sur-Yvette (France); Guertin, Arnaud; Thiolliere, Nicolas [SUBATECH, Nantes (France); Konobeyev, Alexander Yu. [FZK/IRS, Karlsruhe (Germany); Latge, Christian [CEA/DEN/DTN/DIR, St. Paul Lez Durance (France); Lemaire, Sebastien [CEA/DAM/DCSA/SCGA, Bruyeres-le-Chatel (France)

    2008-07-01

    The MEGAPIE project aimed to design, build and operate a liquid metal spallation neutron target of 1 MW beam power in the SINQ facility at the Paul Scherrer Institut (Villigen, Switzerland). The project is an important step in the road-map towards the demonstration of the Accelerator Driven System (ADS) concept and high power liquid metal targets in general. Following the design phase, an experimental program was defined to provide a complete characterization of the facility by performing a 'mapping' of the neutron flux at different points, from the center of the target to the beam lines. The neutronic performance of the target was studied using different experimental techniques with the goals of validating the Monte Carlo codes used in the design of the target; additionally, the performance was compared with the solid lead targets used before and after the MEGAPIE experiment. (authors)

  9. Neutronic performances of the MEGAPIE target

    Energy Technology Data Exchange (ETDEWEB)

    Panebianco, S.; Bringer, O.; Chabod, S.; Dupont, E.; Letourneau, A. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA/SPhN), 91- Gif sur Yvette (France); Beauvais, P.; Lotrus, P.; Molinie, F.; Toussaint, J.Ch. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA), 91- Gif sur Yvette (France); Chartier, F. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC/SECR), 91 - Gif sur Yvette (France); Oriol, L. [CEA Cadarache, Dept. d' Etudes des Reacteurs (DEN/DER/SPEX), 13 - Saint Paul lez Durance (France)

    2008-07-01

    The MEGAPIE project is a key experiment on the road to Accelerator Driven Systems and it provides the scientific community with unique data on the behavior of a liquid lead-bismuth spallation target under realistic and long term irradiation conditions. The neutronic of such target is of course of prime importance when considering its final destination as an intense neutron source. This is the motivation to characterize the inside neutron flux of the target in operation. A complex detector, made of 8 'micro' fission-chambers, has been built and installed in the core of the target, few tens of centimeters from the proton/Pb-Bi interaction zone. This detector is designed to measure the absolute neutron flux inside the target, to give its spatial distribution and to correlate its temporal variations with the beam intensity. Moreover, integral information on the neutron energy distribution as a function of the position along the beam axis could be extracted, giving integral constraints on the neutron production models implemented in transport codes such as MCNPX. (authors)

  10. Neutronic performances of the MEGAPIE target

    CERN Document Server

    Panebianco, S; Bringer, O; Chabod, S; Chartier, F; Dupont, E; Letourneau, A; Lotrus, P; Oriol, L; Molinie, F; Toussaint, J Ch

    2007-01-01

    The MEGAPIE project is a key experiment on the road to Accelerator Driven Systems and it provides the scientific community with unique data on the behavior of a liquid lead-bismuth spallation target under realistic and long term irradiation conditions. The neutronic of such target is of course of prime importance when considering its final destination as an intense neutron source. This is the motivation to characterize the inside neutron flux of the target in operation. A complex detector, made of 8 micro fission-chambers, has been built and installed in the core of the target, few tens of centimeters from the proton/Pb-Bi interaction zone. This detector is designed to measure the absolute neutron flux inside the target, to give its spatial distribution and to correlate its temporal variations with the beam intensity. Moreover, integral information on the neutron energy distribution as a function of the position along the beam axis could be extracted, giving integral constraints on the neutron production mode...

  11. 10 CFR 39.55 - Tritium neutron generator target sources.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target...) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg or in a...

  12. System design considerations for fast-neutron interrogation systems

    Energy Technology Data Exchange (ETDEWEB)

    Micklich, B.J.; Curry, B.P.; Fink, C.L.; Smith, D.L.; Yule, T.J.

    1993-10-01

    Nonintrusive interrogation techniques that employ fast neutrons are of interest because of their sensitivity to light elements such as carbon, nitrogen, and oxygen. The primary requirement of a fast-neutron inspection system is to determine the value of atomic densities, or their ratios, over a volumetric grid superimposed on the object being interrogated. There are a wide variety of fast-neutron techniques that can provide this information. The differences between the various nuclear systems can be considered in light of the trade-offs relative to the performance requirements for each system`s components. Given a set of performance criteria, the operational requirements of the proposed nuclear systems may also differ. For instance, resolution standards will drive scanning times and tomographic requirements, both of which vary for the different approaches. We are modelling a number of the fast-neutron interrogation techniques currently under consideration, to include Fast Neutron Transmission Spectroscopy (FNTS), Pulsed Fast Neutron Analysis (PFNA), and its variant, 14-MeV Associated Particle Imaging (API). The goals of this effort are to determine the component requirements for each technique, identify trade-offs that system performance standards impose upon those component requirements, and assess the relative advantages and disadvantages of the different approaches. In determining the component requirements, we will consider how they are driven by system performance standards, such as image resolution, scanning time, and statistical uncertainty. In considering the trade-offs between system components, we concentrate primarily on those which are common to all approaches, for example: source characteristics versus detector array requirements. We will then use the analysis to propose some figures-of-merit that enable performance comparisons between the various fast-neutron systems under consideration. The status of this ongoing effort is presented.

  13. Polarised neutron scattering from dynamic polarised targets in biology

    Science.gov (United States)

    Knop, W.; Hirai, M.; Olah, G.; Meerwinck, W.; Schink, H.-J.; Stuhrman, H. B.; Wagner, R.; Wenkow-EsSouni, M.; Zhao, J.; Schärpf, O.; Crichton, R. R.; Krumpolc, M.; Nierhaus, K. H.; Niinikoski, T. O.; Rijllart, A.

    1991-10-01

    The contrast giving rise to neutron small-angle scattering can be enhanced considerably by polarisation of the hydrogen nuclei [J. des Coizeaux and G. Jannink, Les Polymères en Solution, Les Editions de Physique, F-91944 Les Ulis, France (1987)]. Using polarised neutrons the scattering from protonated labels in a deuterated matrix will increase by an order of magnitude. This is the basis of nuclear spin contrast variation, a method which is of particular interest for the in situ structure determination of macromolecular components. A new polarised target for neutron scattering has been designed by CERN and tested successfully at FRG-1 of the GKSS research centre. For the purpose of thermal-neutron scattering the frozen solutions of biomolecules are immersed in liquid helium 4, which is thermally coupled to the cooling mixture of helium 3/helium 4 of the dilution refrigerator. The nuclear spins are aligned with respect to the external magnetic field-parallel or antiparallel-by dynamic nuclear polarisation (DNP). The gain in neutron scattering compared to earlier experiments using direct cooling of the sample by helium 3 is a factor of 30. Another factor of 30 arises from the installation of the cold source and the beryllium reflector in FRG-1 [W. Knop et al., J. Appl. Cryst. 22 (1989) 352]. Pure nuclear spin targets are produced from dynamic polarised targets by selective depolarisation. In biological material only the hydrogen isotopes contribute significantly to polarised neutron scattering. Thus, saturation of the proton NMR yields a deuteron target, provided the target material has been enriched by the latter isotope. A proton target is obtained from the dynamic polarised target by saturation of deuteron NMR. This leads to six additional scattering functions reflecting the proton and deuteron spin densities and the correlations between the polarised isotopes. Polarised neutron scattering from nuclear spin targets of apoferritin and various derivatives of the

  14. Influence of the target excitations on neutron cross section calculations

    Energy Technology Data Exchange (ETDEWEB)

    Cabezas, R.; Lubian, J. [Center for Applied Studies to Nuclear Development, Havana (Cuba)

    1994-12-31

    Considerable progress has been made in the use of the nuclear models and methods to derive physically meaningful parameters for model calculations. In this sense, we analyze the influence of the collective modes of excitation of the target nucleus on the cross section calculations in some medium atomic-weight nuclei, where spectroscopic studies show evidence of anharmonic vibrations, nonaxial deformations and so on. Coupled channel calculations for low-energy neutron inelastic scattering to collective states in {sup 48}Ti, {sup 54}Cr and {sup 62}Ni isotopes are made using the Davydov-Chaban model (DCM). It is shown, that the consideration of the structural features of the target nucleus excitation in the cross section calculations guarantees the agreement with the experimental measurements.

  15. Lithium neutron producing target for BINP accelerator-based neutron source.

    Science.gov (United States)

    Bayanov, B; Belov, V; Kindyuk, V; Oparin, E; Taskaev, S

    2004-11-01

    Pilot innovative accelerator-based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. One of the main elements of the facility is lithium target, that produces neutrons via threshold (7)Li(p,n)(7)Be reaction at 25 kW proton beam with energies 1.915 or 2.5 MeV. In the present report, the results of experiments on neutron producing target prototype are presented, the results of calculations of hydraulic resistance for heat carrier flow and lithium layer temperature are shown. Calculation showed that the lithium target could run up to 10 mA proton beam before melting. Choice of target variant is substantiated. Program of immediate necessary experiments is described. Target design for neutron source constructed at BINP is presented. Manufacturing the neutron producing target up to the end of 2004 and obtaining a neutron beam on BINP accelerator-based neutron source are planned during 2005.

  16. Lithium neutron producing target for BINP accelerator-based neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Bayanov, B.; Belov, V.; Kindyuk, V.; Oparin, E.; Taskaev, S. E-mail: taskaev@inp.nsk.su

    2004-11-01

    Pilot innovative accelerator-based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. One of the main elements of the facility is lithium target, that produces neutrons via threshold {sup 7}Li(p,n){sup 7}Be reaction at 25 kW proton beam with energies 1.915 or 2.5 MeV. In the present report, the results of experiments on neutron producing target prototype are presented, the results of calculations of hydraulic resistance for heat carrier flow and lithium layer temperature are shown. Calculation showed that the lithium target could run up to 10 mA proton beam before melting. Choice of target variant is substantiated. Program of immediate necessary experiments is described. Target design for neutron source constructed at BINP is presented. Manufacturing the neutron producing target up to the end of 2004 and obtaining a neutron beam on BINP accelerator-based neutron source are planned during 2005.

  17. Thick beryllium target as an epithermal neutron source for neutron capture therapy.

    Science.gov (United States)

    Wang, C K; Moore, B R

    1994-10-01

    Accelerator-based intense epithermal neutron sources for Neutron Capture Therapy (NCT) have been considered as an alternative to nuclear reactors. Lithium (Li) has generally received the widest attention for this application, since the threshold energy is low and neutron yield is high. Because of the poor thermal and chemical properties of Li and the need for heat removal in the target, the design of Li targets has been quite difficult. Beryllium (Be) has been thought of as an alternative target because of its good thermal and chemical properties and reasonable neutron yield. However, in order to have a neutron yield comparable to that of a thick Li target bombarded with 2.5 MeV protons, the proton energy required for a thick Be target must be approaching 4 MeV. Consequently, the neutrons emitted are more energetic. In addition, a significant amount of high-energy gamma rays, which is undesirable, will occur when Be is bombarded with low-energy protons. Regardless of the more energetic neutrons and additional gamma rays, in this paper it is shown that it is possible to develop a high-quality and high-intensity epithermal neutron beam based on a thick Be target for NCT treatment. For a fixed proton current, the optimal Be-target-based beam (with 4-MeV protons) can produce a neutron beam, with both quality and intensity slightly better than those produced by the optimal Li-target-based beam (with 2.5-MeV protons). The single-session NCT treatment time for the optimal Be-target-based beam is estimated to be 88 min for a proton current of 50 mA.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Considerations in the design of an improved transportable neutron spectrometer

    CERN Document Server

    Williams, A M; Brushwood, J M; Beeley, P A

    2002-01-01

    The Transportable Neutron Spectrometer (TNS) has been used by the Ministry of Defence for over 15 years to characterise neutron fields in workplace environments and provide local correction factors for both area and personal dosimeters. In light of advances in neutron spectrometry, a programme to evaluate and improve TNS has been initiated. This paper describes TNS, presents its operation in known radioisotope fields and in a reactor environment. Deficiencies in the operation of the instrument are highlighted, together with proposals for updating the response functions and spectrum unfolding methodologies.

  19. Characterisation of neutron and gamma-ray emission from thick target Be(p,n) reaction for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Guzek, J.; Mateva, T.; Tapper, U.A.S. [De Beers Diamond Res. Lab., Southdale (South Africa); McMurray, W.R. [National Accelerator Centre, Van de Graaff Group, P.O. Box 72, Faure 7131 (South Africa); Franklyn, C.B. [Atomic Energy Corporation of South Africa, P.O. Box 582, Pretoria (South Africa)

    1998-04-01

    Low energy accelerator-based neutron sources have promising potential for use in a clinical treatment of cancer with boron neutron capture therapy (BNCT) and boron neutron capture synovectomy (BNCS). Such sources often utilise a thick target Be(p,n) reaction using incident proton energies from several hundred keV to 1-2 MeV above the reaction threshold of 2.06 MeV. The resulting neutron and gamma-ray beams require considerable moderation and filtration in order to obtain thermal and epithermal neutron fluxes for therapy. The detailed knowledge of neutron and gamma-ray spectra, yield and angular distribution are necessary in order to design effective moderators and filters to be used for the treatment. Thick and thin beryllium target neutron and gamma spectra have been investigated in detail using the time-of-flight (TOF) technique, for incident proton energies from above threshold to 4 MeV. The results show characteristics of neutron and gamma-ray production of importance for the application of this neutron source for BNCT and BNCS. (orig.) 6 refs.

  20. Targets for bulk hydrogen analysis using thermal neutrons

    CERN Document Server

    Csikai, J; Buczko, C M

    2002-01-01

    The reflection property of substances can be characterized by the reflection cross-section of thermal neutrons, sigma subbeta. A combination of the targets with thin polyethylene foils allowed an estimation of the flux depression of thermal neutrons caused by a bulk sample containing highly absorbing elements or compounds. Some new and more accurate sigma subbeta values were determined by using the combined target arrangement. For the ratio, R of the reflection and the elastic scattering cross-sections of thermal neutrons, R=sigma subbeta/sigma sub E sub L a value of 0.60+-0.02 was found on the basis of the data obtained for a number of elements from H to Pb. Using this correlation factor, and the sigma sub E sub L values, the unknown sigma subbeta data can be deduced. The equivalent thicknesses, to polyethylene or hydrogen, of the different target materials were determined from the sigma subbeta values.

  1. Active helium target: Neutron scalar polarizability extraction via Compton scattering

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Meg, E-mail: mmorris@mta.ca; Hornidge, David [Mount Allison University, Sackville, New Brunswick (Canada); Annand, John; Strandberg, Bruno [University of Glasgow, Scotland (United Kingdom)

    2015-12-31

    Precise measurement of the neutron scalar polarizabilities has been a lasting challenge because of the lack of a free-neutron target. Led by the University of Glasgow and the Mount Allison University groups of the A2 collaboration in Mainz, Germany, preparations have begun to test a recent theoretical model with an active helium target with the hope of determining these elusive quantities with small statistical, systematic, and model-dependent errors. Apparatus testing and background-event simulations have been carried out, with the full experiment projected to run in 2015. Once determined, these values can be applied to help understand quantum chromodynamics in the nonperturbative region.

  2. Long-Lifetime Low-Scatter Neutron Polarization Target

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Jonathan M. Richardson

    2004-07-09

    Polarized neutrons scattering is an important technology for characterizing magnetic and other materials. Polarized helium three (P-3He) is a novel technology for creating polarized beams and, perhaps more importantly, for the analysis of polarization in highly divergent scattered beams. Analysis of scattered beams requires specialized targets with complex geometries to ensure accurate results. Special materials and handling procedures are required to give the targets a long useful lifetime. In most cases, the targets must be shielded from stray magnetic fields from nearby equipment. SRL has developed and demonstrated hybrid targets made from glass and aluminum. We have also developed and calibrated a low-field NMR system for measuring polarization lifetimes. We have demonstrated that our low-field system is able to measure NMR signals in the presence of conducting (metallic) cell elements. We have also demonstrated a non-magnetic valve that can be used to seal the cells. We feel that these accomplishments in Phase I are sufficient to ensure a successful Phase II program. The commercial market for this technology is solid. There are over nine neutron scattering centers in the US and Canada and over 22 abroad. Currently, the US plans to build a new $1.4B scattering facility called the Spallation Neutron Source (SNS). The technology developed in this project will allow SRL to supply targets to both existing and future facilities. SRL is also involved with the application of P-3He to medical imaging.

  3. Thermal hydraulic design and decay heat removal of a solid target for a spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, N. [Department of Mechanical Engineering, Kobe University, Kobe (Japan)]. E-mail: takenaka@mech.kobe-u.ac.jp; Nio, D. [Hokkaido University, Sapporo (Japan); Kiyanagi, Y. [Hokkaido University, Sapporo (Japan); Mishima, K. [Kyoto University Research Reactor Institute, Kumatori (Japan); Kawai, M. [High Energy Accelerator Research Institute, Tsukuba (Japan); Furusaka, M. [High Energy Accelerator Research Institute, Tsukuba (Japan)

    2005-08-01

    Thermal hydraulic design and thermal stress calculations were conducted for a water-cooled solid target irradiated by a MW-class proton beam for a spallation neutron source. Plate type and rod bundle type targets were examined. The thickness of the plate and the diameter of the rod were determined based on the maximum and the wall surface temperature. The thermal stress distributions were calculated by a finite element method (FEM). The neutronics performance of the target is roughly proportional to its average density. The averaged densities of the designed targets were calculated for tungsten plates, tantalum-clad tungsten plates, tungsten rods sheathed by tantalum and Zircaloy and they were compared with mercury density. It was shown that the averaged density was highest for the tungsten plates and was high for the tantalum cladding tungsten plates, the tungsten rods sheathed by tantalum and Zircaloy in order. They were higher than or equal to that of mercury for the 1-2 MW proton beams. Tungsten target without the cladding or the sheath is not practical due to corrosion by water under irradiation condition. Therefore, the tantalum cladding tungsten plate already made successfully by HIP and the sheathed tungsten rod are the candidate of high performance solid targets. The decay heat of each target was calculated. It was low enough low compared to that of ISIS for the target without tantalum but was about four times as high as that of ISIS when the thickness of the tantalum cladding was 0.5 mm. Heat removal methods of the decay heat with tantalum were examined. It was shown that a special cooling system was required for the target exchange when tantalum was used for the target. It was concluded that the tungsten rod target sheathed with stainless steel or Zircaloy was the most reliable from the safety considerations and had similar neutronics performance to that of mercury.

  4. Thermal hydraulic design and decay heat removal of a solid target for a spallation neutron source

    Science.gov (United States)

    Takenaka, N.; Nio, D.; Kiyanagi, Y.; Mishima, K.; Kawai, M.; Furusaka, M.

    2005-08-01

    Thermal hydraulic design and thermal stress calculations were conducted for a water-cooled solid target irradiated by a MW-class proton beam for a spallation neutron source. Plate type and rod bundle type targets were examined. The thickness of the plate and the diameter of the rod were determined based on the maximum and the wall surface temperature. The thermal stress distributions were calculated by a finite element method (FEM). The neutronics performance of the target is roughly proportional to its average density. The averaged densities of the designed targets were calculated for tungsten plates, tantalum clad tungsten plates, tungsten rods sheathed by tantalum and Zircaloy and they were compared with mercury density. It was shown that the averaged density was highest for the tungsten plates and was high for the tantalum cladding tungsten plates, the tungsten rods sheathed by tantalum and Zircaloy in order. They were higher than or equal to that of mercury for the 1 2 MW proton beams. Tungsten target without the cladding or the sheath is not practical due to corrosion by water under irradiation condition. Therefore, the tantalum cladding tungsten plate already made successfully by HIP and the sheathed tungsten rod are the candidate of high performance solid targets. The decay heat of each target was calculated. It was low enough low compared to that of ISIS for the target without tantalum but was about four times as high as that of ISIS when the thickness of the tantalum cladding was 0.5 mm. Heat removal methods of the decay heat with tantalum were examined. It was shown that a special cooling system was required for the target exchange when tantalum was used for the target. It was concluded that the tungsten rod target sheathed with stainless steel or Zircaloy was the most reliable from the safety considerations and had similar neutronics performance to that of mercury.

  5. Picosecond Neutron Yields from Ultra-Intense Laser-Target Interactions

    Science.gov (United States)

    Ellison, C. Leland; Fuchs, Julien

    2009-11-01

    High-flux neutron sources for neutron imaging and materials analysis applications have typically been provided by accelerator-based (Spallation Neutron Source) and reactor-based (High Flux Isotope Reactor) neutron sources. A novel approach is to use ultra-intense (> 10^18 W/cm^2) laser-target interactions to generate picosecond, collimated neutrons. Here we examine the feasibility of a source based on current (LULI) and upcoming laser facility capabilities. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. The parameters of the deuteron beam are well understood from laser-plasma and laser-target studies relevant to fast-ignition fusion. Expected neutron yields are presented in comparison to conventional neutron sources, previous experimental neutron yields, and within the context of neutron shielding safety requirements.

  6. Oak Ridge Spallation Neutron Source (ORSNS) target station design integration

    Energy Technology Data Exchange (ETDEWEB)

    McManamy, T.; Booth, R.; Cleaves, J.; Gabriel, T. [and others

    1996-06-01

    The conceptual design for a 1- to 3-MW short pulse spallation source with a liquid mercury target has been started recently. The design tools and methods being developed to define requirements, integrate the work, and provide early cost guidance will be presented with a summary of the current target station design status. The initial design point was selected with performance and cost estimate projections by a systems code. This code was developed recently using cost estimates from the Brookhaven Pulsed Spallation Neutron Source study and experience from the Advanced Neutron Source Project`s conceptual design. It will be updated and improved as the design develops. Performance was characterized by a simplified figure of merit based on a ratio of neutron production to costs. A work breakdown structure was developed, with simplified systems diagrams used to define interfaces and system responsibilities. A risk assessment method was used to identify potential problems, to identify required research and development (R&D), and to aid contingency development. Preliminary 3-D models of the target station are being used to develop remote maintenance concepts and to estimate costs.

  7. Mercury target R&D for the Oak Ridge spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haines, J.R.; DiStefano, J.; Farrell, K.; Gabriel, T.A. [Oak Ridge National Lab., TN (United States)] [and others

    1996-06-01

    The conceptual design for the Oak Ridge Spallation Neutron Source (ORSNS) incorporates liquid mercury as its reference target material. A flowing liquid target was selected mainly because of the increased power handling capability possible with the convective transport process. The major reasons for choosing mercury as the liquid target material are because it: (1) is a liquid at room temperature, (2) has good heat transport properties, and (3) has a high atomic number and mass density resulting in high neutron yield and source brightness. Since liquid targets are not widely utilized in presently operating accelerator targets and because of the challenges posed by the intense, pulsed thermal energy deposition ({approximately}20-100 kJ deposited during each 1-10 {mu}s pulse), considerable R&D is planned for the mercury target concept. The key feasibility issue that will be addressed in early R&D efforts are the effects of the thermal shock environment, which will include development and testing of approaches to mitigate these effects. Materials compatiblity and ES&H issues associated with the use of liquid mercury are also of major importance in early R&D efforts. A brief description of the mercury target design concept, results of initial evaluations of its performance characteristics, identification of its critical issues, and an outline of the R&D program aimed at addressing these issues will be presented.

  8. An algorithm for computing thick target differential p-Li neutron yields near threshold

    Science.gov (United States)

    Lee, C. L.; Zhou, X.-L.

    1999-06-01

    The 7Li(p,n)7Be reaction is a good source of neutrons for accelerator boron neutron capture therapy (BNCT). Both reactor and accelerator neutron sources produce fast neutrons, which must be moderated since BNCT uses epithermal neutrons. Near-threshold BNCT uses proton energies only tens of keV above the reaction threshold, which reduces the thick target neutron yield but also produces neutrons closer to epithermal energies, so that less moderation is required. Accurate methods for calculating near-threshold differential neutron yields from thick targets of lithium, as well as certain low weight lithium compounds, were developed for BNCT source design. Neutron yields for proton beams up to 2.8 MeV will be presented. Good agreement with yields from several targets will be demonstrated.

  9. Architecture Considerations of Time Sensitive Targeting and NATO TST Tool

    Science.gov (United States)

    2013-06-01

    Architecture Considerations of Time Sensitive Targeting and NATO TST Tool Orhan Cetinkaya, PhD Yakup Yildirim, PhD NCI Agency, 19-21 June 2013...SAR) 18. NUMBER OF PAGES 18 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b . ABSTRACT unclassified c. THIS PAGE unclassified...8217’_’ _’ •_· __ ~==============================================~--0-~ __ is-ta_r_~ ~ NATO UNCLASSIFIED 18 Questions? Orhan Cetinkaya, PhD Principal Scientist

  10. Estimations of neutron yield from beryllium target irradiated by SPring-8 hard synchrotron radiation

    CERN Document Server

    Gryaznykh, D A; Plokhoi, V V

    2000-01-01

    The possibility of creating a neutron source based on ''SPring-8'' synchrotron radiation interaction with beryllium targets is discussed. The possible neutron yield is estimated to be of order 10 sup 1 sup 2 s sup - sup 1 .

  11. Integral measurements of neutron production in spallation targets; Mesure integrale de la production de neutrons dans des cibles de spallation

    Energy Technology Data Exchange (ETDEWEB)

    Frehaut, J.; Deneuville, D.; Ledoux, X.; Lochard, J.P.; Longuet, J.L.; Petibon, E.; Alrick, K.; Bownan, D.; Cverna, F.; King, N.S.P.; Morgan, G.L. [Los Alamos National Lab., NM (United States); Greene, G.; Hanson, A.; Snead, L. [Brookhaven National Lab., Upton, NY (United States); Thompson, R. [Bechtel Nevada Corp., Las Vegas, NV (United States); Ward, T

    1998-12-31

    Measurements of neutron production for thick iron, tungsten and lead targets of different diameter prototypic for spallation systems have been made at SATURNE in an incident proton energy range from 400 MeV to 2 GeV. TIERCE code system calculations are in good agreement with experiment for iron and large diameter tungsten and lead targets. They overestimate the measured neutron production for tungsten and lead targets for diameter {<=}20 cm. (author) 10 refs.

  12. Production, separation and target preparation of 171Tm an 147Pm for neutron cross section measurements

    CERN Document Server

    Heinitz, S; Schumann, D; Dressler, R; Kivel, N; Guerrero, C; Köster, U; Tessler, M; Paul, M; Halfon, S

    2015-01-01

    The knowledge of the neutron capture cross sections of s-process branching point isotopes represents a basic requirement for the understanding of star evolution. Since such branching point isotopes are by definition radioactive, the measurement of their cross sections from thermal to stellar energies becomes a challenging task. Considerable amounts of material have to be produced, representing a significant radioactive hazard. We report here on the production and separation of 3.5 mg 171Tm from 240 mg 170Er2O3 and 72 µg 147Pm from 100 mg 146Nd2O3 irradiated at the ILL high flux reactor. Thin targets were prepared with high chemical and radioisotopic purity suitable for neutron capture measurements at n_TOF CERN and the SARAF-LiLiT facility.

  13. Boron neutron capture therapy: Moving toward targeted cancer therapy

    Directory of Open Access Journals (Sweden)

    Hamid Reza Mirzaei

    2016-01-01

    Full Text Available Boron neutron capture therapy (BNCT occurs when a stable isotope, boton-10, is irradiated with low-energy thermal neutrons to yield stripped down helium-4 nuclei and lithium-7 nuclei. It is a binary therapy in the treatment of cancer in which a cytotoxic event is triggered when an atom placed in a cancer cell. Here, we provide an overview on the application of BNCT in cancer therapy as well as current preclinical and clinical evidence on the efficacy of BNCT in the treatment of melanoma, brain tumors, head and neck cancer, and thyroid cancer. Several studies have shown that BNCT is effective in patients who had been treated with a full dose of conventional radiotherapy, because of its selectivity. In addition, BNCT is dependent on the normal/tumor tissue ratio of boron distribution. Increasing evidence has shown that BNCT can be combined with different drug delivery systems to enhance the delivery of boron to cancer cells. The flexibility of BNCT to be used in combination with different tumor-targeting approaches has made this strategy a promising option for cancer therapy. This review aims to provide a state-of-the-art overview of the recent advances in the use of BNCT for targeted therapy of cancer.

  14. Neutron dose equivalent rate in intermediate energy heavy ion target area

    CERN Document Server

    Li Gui Sheng; Li Zong Wei; Su You Wu; Zhang Shu Mi

    2000-01-01

    The fluence rate distributions of neutrons emitted in the reactions of 50 MeV/u sup 1 sup 8 O-ion on thick Be, Cu, Au targets were measured with an activation method of threshold detectors and the neutron dose equivalent rate distributions at 1 m from the targets in intermediate energy heavy ion target area were obtained using the conversion coefficients for neutron fluence rate to ambient dose equivalent rate.

  15. Neutrons produced by 75MeV/u 12C—ion on thick targets

    Institute of Scientific and Technical Information of China (English)

    LiGisheng; ZHANGTianmei; 等

    1999-01-01

    Fluence rates and angular distributions of the neutron emitted by 75MeV/u 12C-ion bombardment on thick Be and Au targets have been measured by means of the threshold detector activation method.Based on that,the neutron yields,emission rates in the forward direction and neutron dose equivalent rate distributions were deduced.

  16. Secondary neutron production from thick Pb target by light particle irradiation

    CERN Document Server

    Adloff, J C; Debeauvais, M; Fernández, F; Krivopustov, M; Kulakov, B A; Sosnin, A; Zamani, M

    1999-01-01

    Neutron multiplicities from spallation neutron sources were measured by Solid State Nuclear Track Detectors. Light particles as protons, deuterons and alphas in the GeV range were used on Pb targets. For neutron thermalization the targets were covered by 6 cm paraffin moderator. Neutron multiplicity distributions were studied inside and on the moderator surface. Comparison of SSNTDs results were made for thermal-epithermal neutrons with sup 1 sup 3 sup 9 La activation method as well as with Dubna DCM/CEM code. Discussion including previous sup 1 sup 2 C results are given.

  17. Lithium target for accelerator based BNCT neutron source: Influence by the proton irradiation on lithium

    Science.gov (United States)

    Fujii, R.; Imahori, Y.; Nakakmura, M.; Takada, M.; Kamada, S.; Hamano, T.; Hoshi, M.; Sato, H.; Itami, J.; Abe, Y.; Fuse, M.

    2012-12-01

    The neutron source for Boron Neutron Capture Therapy (BNCT) is in the transition stage from nuclear reactor to accelerator based neutron source. Generation of low energy neutron can be achieved by 7Li (p, n) 7Be reaction using accelerator based neutron source. Development of small-scale and safe neutron source is within reach. The melting point of lithium that is used for the target is low, and durability is questioned for an extended use at a high current proton beam. In order to test its durability, we have irradiated lithium with proton beam at the same level as the actual current density, and found no deterioration after 3 hours of continuous irradiation. As a result, it is suggested that lithium target can withstand proton irradiation at high current, confirming suitability as accelerator based neutron source for BNCT.

  18. Accelerator-based neutron source using a cold deuterium target with degenerate electrons

    Directory of Open Access Journals (Sweden)

    R. E. Phillips

    2013-07-01

    Full Text Available A neutron generator is considered in which a beam of tritons is incident on a hypothetical cold deuterium target with degenerate electrons. The energy efficiency of neutron generation is found to increase substantially with electron density. Recent reports of potential targets are discussed.

  19. Measurement of neutron yield by 62 MeV proton beam on a thick Beryllium target

    CERN Document Server

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

    2012-01-01

    In the framework of research on IVth generation reactors and high intensity neutron sources a low-power prototype neutron amplifier was recently proposed by INFN. It is based on a low-energy, high current proton cyclotron, whose beam, impinging on a thick Beryllium converter, produces a fast neutron spectrum. The world database on the neutron yield from thick Beryllium target in the 70 MeV proton energy domain is rather scarce. The new measurement was performed at LNS, covering a wide angular range from 0 to 150 degrees and an almost complete neutron energy interval. In this contribution the preliminary data are discussed together with the proposed ADS facility.

  20. Soft error rate simulation and initial design considerations of neutron intercepting silicon chip (NISC)

    Science.gov (United States)

    Celik, Cihangir

    -scale technologies. Prevention of SEEs has been studied and applied in the semiconductor industry by including radiation protection precautions in the system architecture or by using corrective algorithms in the system operation. Decreasing 10B content (20%of natural boron) in the natural boron of Borophosphosilicate glass (BPSG) layers that are conventionally used in the fabrication of semiconductor devices was one of the major radiation protection approaches for the system architecture. Neutron interaction in the BPSG layer was the origin of the SEEs because of the 10B (n,alpha) 7Li reaction products. Both of the particles produced have the capability of ionization in the silicon substrate region, whose thickness is comparable to the ranges of these particles. Using the soft error phenomenon in exactly the opposite manner of the semiconductor industry can provide a new neutron detection system based on the SERs in the semiconductor memories. By investigating the soft error mechanisms in the available semiconductor memories and enhancing the soft error occurrences in these devices, one can convert all memory using intelligent systems into portable, power efficient, directiondependent neutron detectors. The Neutron Intercepting Silicon Chip (NISC) project aims to achieve this goal by introducing 10B-enriched BPSG layers to the semiconductor memory architectures. This research addresses the development of a simulation tool, the NISC Soft Error Analysis Tool (NISCSAT), for soft error modeling and analysis in the semiconductor memories to provide basic design considerations for the NISC. NISCSAT performs particle transport and calculates the soft error probabilities, or SER, depending on energy depositions of the particles in a given memory node model of the NISC. Soft error measurements were performed with commercially available, off-the-shelf semiconductor memories and microprocessors to observe soft error variations with the neutron flux and memory supply voltage. Measurement

  1. Targeting Opioid-Induced Hyperalgesia in Clinical Treatment: Neurobiological Considerations.

    Science.gov (United States)

    Arout, Caroline A; Edens, Ellen; Petrakis, Ismene L; Sofuoglu, Mehmet

    2015-06-01

    Opioid analgesics have become a cornerstone in the treatment of moderate to severe pain, resulting in a steady rise of opioid prescriptions. Subsequently, there has been a striking increase in the number of opioid-dependent individuals, opioid-related overdoses, and fatalities. Clinical use of opioids is further complicated by an increasingly deleterious profile of side effects beyond addiction, including tolerance and opioid-induced hyperalgesia (OIH), where OIH is defined as an increased sensitivity to already painful stimuli. This paradoxical state of increased nociception results from acute and long-term exposure to opioids, and appears to develop in a substantial subset of patients using opioids. Recently, there has been considerable interest in developing an efficacious treatment regimen for acute and chronic pain. However, there are currently no well-established treatments for OIH. Several substrates have emerged as potential modulators of OIH, including the N-methyl-D-aspartate and γ-aminobutyric acid receptors, and most notably, the innate neuroimmune system. This review summarizes the neurobiology of OIH in the context of clinical treatment; specifically, we review evidence for several pathways that show promise for the treatment of pain going forward, as prospective adjuvants to opioid analgesics. Overall, we suggest that this paradoxical state be considered an additional target of clinical treatment for chronic pain.

  2. Transfer reactions at the neutron dripline with triton target

    CERN Document Server

    Borge, M J G; Fynbo, H O U; Gomez Camacho, J; Johansen, J; Johansson, H T; Jonson, B; Krücken, R; Kurcewicz, J; Martel, I; Moro, A; Mücher, D; Nilsson, T; Nyman, G; Raabe, R; Randisi, G; Riisager, K; Sambi, S; Sanchez-Benitez, AM; Tengblad, O

    2012-01-01

    Two-neutron transfer to $^{9}$Li will populate the ground state of $^{11}$Li as well as low-lying resonances in a way that is complementary to studies of these states performed at higher beam energies. We aim at detecting the charged particles from the transfer reactions as well as neutrons coming from the decay of possible $^{11}$Li resonances.

  3. Transfer reactions at the neutron dripline with triton target

    CERN Multimedia

    Two-neutron transfer to $^{9}$Li will populate the ground state of $^{11}$Li as well as low-lying resonances in a way that is complementary to studies of these states performed at higher beam energies. We aim at detecting the charged particles from the transfer reactions as well as neutrons coming from the decay of possible $^{11}$Li resonances.

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

    Science.gov (United States)

    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.

  5. Comparison of bulk and pitcher-catcher targets for laser-driven neutron production

    Science.gov (United States)

    Willingale, L.; Petrov, G. M.; Maksimchuk, A.; Davis, J.; Freeman, R. R.; Joglekar, A. S.; Matsuoka, T.; Murphy, C. D.; Ovchinnikov, V. M.; Thomas, A. G. R.; Van Woerkom, L.; Krushelnick, K.

    2011-08-01

    Laser-driven d(d, n)-3He beam-target fusion neutron production from bulk deuterated plastic (CD) targets is compared with a pitcher-catcher target scheme using an identical laser and detector arrangement. For laser intensities in the range of (1-3) × 1019 W cm-2, it was found that the bulk targets produced a high yield (5 × 104 neutrons per steradian) beamed preferentially in the laser propagation direction. Numerical modeling shows the importance of considering the temperature adjusted stopping powers to correctly model the neutron production. The bulk CD targets have a high background target temperature leading to a reduced stopping power for the deuterons, which increases the probability of generating neutrons by fusion. Neutron production from the pitcher-catcher targets was not as efficient since it does not benefit from the reduced stopping power in the cold catcher target. Also, the inhibition of the deuteron acceleration by a proton rich contamination layer significantly reduces the pitcher-catcher neutron production.

  6. Target station shielding issues at the spallation neutron source.

    Science.gov (United States)

    Ferguson, P D; Gallmeier, F X; Iverson, E B; Popova, I I

    2005-01-01

    Recent spallation neutron source shielding activities in support of the neutron beam shutters and the hot cell walls are presented. Existing neutron beam shutters can be replaced with concrete at low power or with concrete and steel at approximately 500 kW of beam power. Potential voids in the hot cell walls are analysed to determine the impact on dose rates as a function of void size. A change in the type of shielding work is noted as the project moved from the early design stages as a 'green field' site to the current stage as a construction project nearing completion, where issues to be addressed are approaching retrofit-type analyses.

  7. Spallation yield of neutrons produced in thick lead target bombarded with 250 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Ma, F., E-mail: mf@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhanga, X.Y.; Ju, Y.Q.; Zhang, H.B.; Ge, H.L.; Wang, J.G. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou, B. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Li, Y.Y.; Xu, X.W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Luo, P.; Yang, L.; Zhang, Y.B.; Li, J.Y.; Xu, J.K. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liang, T.J. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S.L. [University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Y.W.; Gu, L. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2015-01-01

    The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally. The neutron production was measured with the water-bath gold method. The thermal neutron distributions in the water were determined according to the measured activities of Au foils. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data. It was found out that the Au foils with cadmium cover significantly changed the spacial distribution of the thermal neutron field. The corrected neutron yield was deduced to be 2.23±0.19 n/proton by considering the influence of the Cd cover on the thermal neutron flux.

  8. Spallation yield of neutrons produced in thick lead target bombarded with 250 MeV protons

    Science.gov (United States)

    Chen, L.; Ma, F.; Zhanga, X. Y.; Ju, Y. Q.; Zhang, H. B.; Ge, H. L.; Wang, J. G.; Zhou, B.; Li, Y. Y.; Xu, X. W.; Luo, P.; Yang, L.; Zhang, Y. B.; Li, J. Y.; Xu, J. K.; Liang, T. J.; Wang, S. L.; Yang, Y. W.; Gu, L.

    2015-01-01

    The neutron yield from thick target of Pb irradiated with 250 MeV protons has been studied experimentally. The neutron production was measured with the water-bath gold method. The thermal neutron distributions in the water were determined according to the measured activities of Au foils. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data. It was found out that the Au foils with cadmium cover significantly changed the spacial distribution of the thermal neutron field. The corrected neutron yield was deduced to be 2.23 ± 0.19 n/proton by considering the influence of the Cd cover on the thermal neutron flux.

  9. Neutron and fission yields from high-energy deuterons in infinite /sup 238/U targets

    Energy Technology Data Exchange (ETDEWEB)

    Canfield, E.

    1965-06-28

    Early work on the interaction of high energy deuterons with large /sup 238/U targets is reexamined and current theoretical study is discussed. Results of fission and neutron yield calculations are compared with experiment. (SDF)

  10. Test of high density UC targets development at Gatchina for neutron rich radioactive beam facilities

    CERN Document Server

    Lhersonneau, G; Lanchais, A; Rizzi, V; Tecchio, L.B; Bajeat, O; Essabaa, S; Lau, C; Cheikh Mhamed, M; Roussière, B; Barzakh, A.E; Fedorov, D.V; lonan, A.M; lvanov, V.S; Mezilev, K.A; Moroz, F.V; Orlov, S.YU; Panteleevc, V.N; Volkovc, YU.M; Dubois, M; Eléon, C; Gaubert, G; Jardin, P; Leroy, R; Saint Laurent, M.G; Villari, A.C.C; Stroe, L; 10.1016/j.nimb.2008.05.033

    2008-01-01

    Production of on-line mass separator neutron rich isotopes using fission induced by 1 GeV protons on high density uranium carbide has been investigate and results compared with the low density targets yields.

  11. Uranium target for electron accelerator based neutron source for BNCT

    Science.gov (United States)

    Tonchev, A. P.; Harmon, F.; Collens, T. J.; Kennedy, K.; Sabourov, A.; Harker, Y. D.; Nigg, D. W.; Jones, J. L.

    2001-07-01

    Calculations of the epithermal-neutron yield of photoneutrons from a uranium-beryllium converter using a 27 MeV electron linear accelerator have been investigated. In this concept, relativistic electron beams from a 30 MeV LINAC impinge upon a small uranium sphere surrounded by a cylindrical tank of circulating heavy water (D2O) nested in a beryllium cube. The photo-fission neutron spectrum from the uranium sphere is thermalized in deuterium and beryllium, filtered and moderated in special material (AlF3/Al/LiF), and directed to the patient. The results of these calculations demonstrate that photoneutron devices could offer a promising alternative to nuclear reactors for the production of epithermal neutrons for Neutron Capture Therapy. The predicted parameter for the epithermal flux is more than 108n.cm-2.mA-1.

  12. Considerations on radar localization in multi-target environments

    Directory of Open Access Journals (Sweden)

    H. Rabe

    2009-05-01

    Full Text Available In a multitude of applications like e.g. in automotive radar systems a localization of multiple passive targets in the observed area is necessary. This contribution presents a robust approach based on trilateration to detect point scatterers in a two-dimensional plane using the reflection and transmission information of only two antennas. The proposed algorithm can identify and remove ambiguities in target detection which unavoidably occur in certain target constellations in such a two-antenna configuration.

  13. Optimized concept design of the target station of Chinese spallation neutron source

    Science.gov (United States)

    Yan, Q. W.; Yin, W.; Yu, B. L.

    2005-08-01

    CSNS (Chinese spallation neutron source) target station, with proton beam power of 100 kW, consists of Tungsten rectangular target surrounded by a beryllium/steel reflector, three wing-moderators and the shield having 18 beam tubes. The leakage neutron intensity from the target (with reflector) and heat deposition on the target, reflector and shield were calculated using Monte Carlo code NMTC/JAM respectively. It is reported that the target having rectangular section will produce more leakage neutron intensity than a square one for the same proton power. The temperature and thermal stress distribution in the target disks were calculated by the finite element method. The performances of moderators were calculated using MCNP-4A code.

  14. Consideration of radar target glint from ST during OMV rendezvous

    Science.gov (United States)

    McDonald, M. W.; Malone, L. B.; Gleason, E. H.

    1985-09-01

    The nature of radar target glint and the factors upon which it depends when using the Hubble Space Telescope as a radar target is discussed. An analysis of the glint problem using a 35 MHz or 94 MHz radar on the orbital maneuvering vehicle is explored. A strategy for overcoming glint is suggested.

  15. Neutronic Assessment of Transmutation Target Compositions in Heterogeneous Sodium Fast Reactor Geometries

    Energy Technology Data Exchange (ETDEWEB)

    Samuel E. Bays; Rodolfo M. Ferrer; Michael A. Pope; Benoit Forget; Mehdi Asgari

    2008-02-01

    The sodium fast reactor is under consideration for consuming the transuranic waste in the spent nuclear fuel generated by light water reactors. This work is concerned with specialized target assemblies for an oxide-fueled sodium fast reactor that are designed exclusively for burning the americium and higher mass actinide component of light water reactor spent nuclear fuel (SNF). The associated gamma and neutron radioactivity, as well as thermal heat, associated with decay of these actinides may significantly complicate fuel handling and fabrication of recycled fast reactor fuel. The objective of using targets is to isolate in a smaller number of assemblies these concentrations of higher actinides, thus reducing the volume of fuel having more rigorous handling requirements or a more complicated fabrication process. This is in contrast to homogeneous recycle where all recycled actinides are distributed among all fuel assemblies. Several heterogeneous core geometries were evaluated to determine the fewest target assemblies required to burn these actinides without violating a set of established fuel performance criteria. The DIF3D/REBUS code from Argonne National Laboratory was used to perform the core physics and accompanying fuel cycle calculations in support of this work. Using the REBUS code, each core design was evaluated at the equilibrium cycle condition.

  16. Comprehensive Measurement of Neutron Yield Produced by 62 MeV Protons on Beryllium Target

    CERN Document Server

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

    2013-01-01

    A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron being installed at LNL for the SPES RIB facility, was recently proposed within INFN-E project. This prototype uses a thick Beryllium converter to produce a fast neutron spectrum feeding a sub-critical reactor core. To complete the design of such facility the new measurement of neutron yield from a thick Beryllium target was performed at LNS. This measurement used liquid scintillator detectors to identify produced neutrons by Pulse Shape Discrimination and Time of Flight technique to measure neutron energy in the range 0.5-62 MeV. To extend the covered neutron energy range He3 detector was used to measure neutrons below 0.5 MeV. The obtained yields were normalized to the charge deposited by the proton beam on the metallic Beryllium target. These techniques allowed to achieve a wide angular coverage from 0 to 150 degrees and to explore almost complete neutron energy interval.

  17. Measurements and parameterization of neutron energy spectra from targets bombarded with 120 GeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Kajimoto, T., E-mail: kajimoto@hiroshima-u.ac.jp [Hiroshima University, Kagamiyama, Higashi-hiroshima 739-8527 (Japan); Shigyo, N. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Sanami, T. [High Energy Accelerator Research Organization, Oho, Tsukuba, Ibaraki 305-0801 (Japan); Iwamoto, Y. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Hagiwara, M. [High Energy Accelerator Research Organization, Oho, Tsukuba, Ibaraki 305-0801 (Japan); Lee, H.S. [Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 790-784 (Korea, Republic of); Soha, A.; Ramberg, E.; Coleman, R.; Jensen, D.; Leveling, A.; Mokhov, N.V.; Boehnlein, D.; Vaziri, K. [Fermi National Accelerator Laboratory, Batavia, IL 60510-5011 (United States); Sakamoto, Y. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Ishibashi, K. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Nakashima, H. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2014-10-15

    Highlights: •Neutron energy spectra from targets bombarded with 120 GeV protons were measured. •The neutron energy was determined with the time-of-flight technique. •The measured spectra were compared with those calculated by PHITS and FLUKA. •Large differences were found between measured and calculated spectra. •The study shows the need to improve models for neutron production in the high energy region. -- Abstract: The energy spectra of neutrons were measured by a time-of-flight method for 120 GeV protons on thick graphite, aluminum, copper, and tungsten targets with an NE213 scintillator at the Fermilab Test Beam Facility. Neutron energy spectra were obtained between 25 and 3000 MeV at emission angles of 30°, 45°, 120°, and 150°. The spectra were parameterized as neutron emissions from three moving sources and then compared with theoretical spectra calculated by PHITS and FLUKA codes. The yields of the theoretical spectra were substantially underestimated compared with the yields of measured spectra. The integrated neutron yields from 25 to 3000 MeV calculated with PHITS code were 16–36% of the experimental yields and those calculated with FLUKA code were 26–57% of the experimental yields for all targets and emission angles.

  18. A spherical shell target scheme for laser-driven neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    He, Min-Qing, E-mail: he-minqing@iapcm.ac.cn; Zhang, Hua; Wu, Si-Zhong; Wu, Jun-Feng; Chen, Mo [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Cai, Hong-Bo, E-mail: cai-hongbo@iapcm.ac.cn; Zhou, Cang-Tao; Cao, Li-Hua; Zheng, Chun-Yang; Zhu, Shao-Ping; He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Dong, Quan-Li [School of Physics and Optoelectronic Engineering, Ludong University, Yantai 260405 (China); Sheng, Zheng-Ming [Department of Physics, Jiaotong University, Shanghai 200240 (China); Pei, Wen-Bing [Shanghai Institute of Laser Plasma, Shanghai 201800 (China)

    2015-12-15

    A scheme for neutron production is investigated in which an ultra-intense laser is irradiated into a two-layer (deuterium and aurum) spherical shell target through the cone shaped entrance hole. It is found that the energy conversion efficiency from laser to target can reach as high as 71%, and deuterium ions are heated to a maximum energy of several MeV from the inner layer surface. These ions are accelerated towards the center of the cavity and accumulated finally with a high density up to tens of critical density in several picoseconds. Two different mechanisms account for the efficient yield of the neutrons in the cavity: (1) At the early stage, the neutrons are generated by the high energy deuterium ions based on the “beam-target” approach. (2) At the later stage, the neutrons are generated by the thermonuclear fusion when the most of the deuterium ions reach equilibrium in the cavity. It is also found that a large number of deuterium ions accelerated inward can pass through the target center and the outer Au layer and finally stopped in the CD{sub 2} layer. This also causes efficient yield of neutrons inside the CD{sub 2} layer due to “beam-target” approach. A postprocessor has been designed to evaluate the neutron yield and the neutron spectrum is obtained.

  19. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-20

    -state heat fluxes of 5–20 MW/m2 and ion fluxes up to 1024 m-2s-1. Since PFCs will have to withstand neutron irradiation displacement damage up to 50 dpa, the target station design must accommodate radioactive specimens (materials to be irradiated in HFIR or at SNS) to enable investigations of the impact of neutron damage on materials. Therefore, the system will have to be able to install and extract irradiated specimens using equipment and methods to avoid sample modification, control contamination, and minimize worker dose. Included in the design considerations will be an assessment of all the steps between neutron irradiation and post-exposure materials examination/characterization, as well as an evaluation of the facility hazard categorization. In particular, the factors associated with the acquisition of radioactive specimens and their preparation, transportation, experimental configuration at the plasma-specimen interface, post-plasma-exposure sample handling, and specimen preparation will be evaluated. Neutronics calculations to determine the dose rates of the samples were carried out for a large number of potential plasma-facing materials.

  20. Neutronic performance of the MEGAPIE spallation target under high power proton beam

    Energy Technology Data Exchange (ETDEWEB)

    Michel-Sendis, F. [CEA - Saclay, Irfu/Service de Physique Nucleaire, F91191 Gif-sur-Yvette (France); Chabod, S. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, 38000 Grenoble (France); Letourneau, A. [CEA - Saclay, Irfu/Service de Physique Nucleaire, F91191 Gif-sur-Yvette (France); Panebianco, S., E-mail: stefano.panebianco@cea.f [CEA - Saclay, Irfu/Service de Physique Nucleaire, F91191 Gif-sur-Yvette (France); Zanini, L. [Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2010-07-01

    The MEGAPIE project, aiming at the construction and operation of a megawatt liquid lead-bismuth spallation target, constitutes the first step in demonstrating the feasibility of liquid heavy metal target technologies as spallation neutron sources. In particular, MEGAPIE is meant to assess the coupling of a high power proton beam with a window-concept heavy liquid metal target. The experiment has been set at the Paul Scherrer Institute (PSI) in Switzerland and, after a 4-month long irradiation, has provided unique data for a better understanding of the behavior of such a target under realistic irradiation conditions. A complex neutron detector has been developed to provide an on-line measurement of the neutron fluency inside the target and close to the proton beam. The detector is based on micrometric fission chambers and activation foils. These two complementary detection techniques have provided a characterization of the neutron flux inside the target for different positions along its axis. Measurements and simulation results presented in this paper aim to provide important recommendations for future accelerator driven systems (ADS) and neutron source developments.

  1. Therapeutic antibodies: market considerations, disease targets and bioprocessing.

    Science.gov (United States)

    Elvin, John G; Couston, Ruairidh G; van der Walle, Christopher F

    2013-01-02

    Antibodies are well established in mainstream clinical practice and present an exciting area for collaborative research and development in industry and academia alike. In this review, we will provide an overview of the current market and an outlook to 2015, focussing on whole antibody molecules while acknowledging the next generation scaffolds containing variable fragments. The market will be discussed in the context of disease targets, particularly in the areas of oncology and immune disorders which generate the greatest revenue by a wide margin. Emerging targets include central nervous system disorders which will also stimulate new delivery strategies. It is becoming increasingly apparent that a better understanding of bioprocessing is required in order to optimize the steps involved in the preparation of a protein prior to formulation. The latter is outside the scope of this review and nor is it our intention to discuss protein delivery and pharmacokinetics. The challenges that lie ahead include the discovery of new disease targets and the development of robust bioprocessing operations.

  2. ANEM: The future neutron production target for Single Event Effect studies at LNL

    Science.gov (United States)

    Acosta Urdaneta, G. C.; Bisello, D.; Esposito, J.; Mastinu, P.; Prete, G.; Silvestrin, L.; Wyss, J.

    2016-11-01

    The design of a fast-neutron ( E > 1 MeV) irradiation facility, devoted to investigating neutron-induced Single Event Effects in microelectronic devices and systems, is under development at the 70MeV, 0.7mA SPES proton cyclotron at LNL (Legnaro, Italy). Here we report on the progress in the design of ANEM (Atmospheric-Neutron EMulator): a water-cooled rotating target capable of producing neutrons with an energy spectrum similar to that of the neutrons present at sea level. In ANEM the protons from the cyclotron alternatively impinge on two circular sectors of Be and W of different areas; the effective neutron spectrum is a weighted combination of the spectra from the two sectors. Thermal-mechanical Finite Element Analysis calculations of the performance of the ANEM prototype indicate that ANEM can deliver fast neutrons with an atmospheric-like energy spectrum in the 1-65MeV energy range with a maximum integral flux φn^{}(1-65 MeV) ≃ 107 n cm-2s-1 at 6m from the target, a very competitive value for Single Event Effects testing.

  3. Synthesis of neutron-rich transuranic nuclei in fissile spallation targets

    CERN Document Server

    Mishustin, Igor; Pshenichnov, Igor; Greiner, Walter

    2014-01-01

    A possibility of synthesizing neutron-reach super-heavy elements in spallation targets of Accelerator Driven Systems (ADS) is considered. A dedicated software called Nuclide Composition Dynamics (NuCoD) was developed to model the evolution of isotope composition in the targets during a long-time irradiation by intense proton and deuteron beams. Simulation results show that transuranic elements up to Bk-249 can be produced in multiple neutron capture reactions in macroscopic quantities. However, the neutron flux achievable in a spallation target is still insufficient to overcome the so-called fermium gap. Further optimization of the target design, in particular, by including moderating material and covering it by a reflector will turn ADS into an alternative source of transuranic elements in addition to nuclear fission reactors.

  4. Target preparation and neutron activation analysis a successful story at IRMM

    CERN Document Server

    Robouch, P; Eguskiza, M; Maguregui, M I; Pommé, S; Ingelbrecht, C

    2002-01-01

    The main task of a target producer is to make well characterized and homogeneous deposits on specific supports. Alpha and/or gamma spectrometry are traditionally used to monitor the quality of actinide deposits. With the increasing demand for enriched stable isotope targets, other analytical techniques, such as ICP-MS and NAA, are needed. This paper presents the application of neutron activation analysis to quality control of 'thin' targets, 'thicker' neutron dosimeters and 'thick' bronze disks prepared by the Reference Materials Unit at the Institute of Reference Materials and Measurements.

  5. Accelerator driven neutron source design via beryllium target and (208)Pb moderator for boron neutron capture therapy in alternative treatment strategy by Monte Carlo method.

    Science.gov (United States)

    Khorshidi, Abdollah

    2017-01-01

    The reactor has increased its area of application into medicine especially boron neutron capture therapy (BNCT); however, accelerator-driven neutron sources can be used for therapy purposes. The present study aimed to discuss an alternative method in BNCT functions by a small cyclotron with low current protons based on Karaj cyclotron in Iran. An epithermal neutron spectrum generator was simulated with 30 MeV proton energy for BNCT purposes. A low current of 300 μA of the proton beam in spallation target concept via 9Be target was accomplished to model neutron spectrum using 208Pb moderator around the target. The graphite reflector and dual layer collimator were planned to prevent and collimate the neutrons produced from proton interactions. Neutron yield per proton, energy distribution, flux, and dose components in the simulated head phantom were estimated by MCNPX code. The neutron beam quality was investigated by diverse filters thicknesses. The maximum epithermal flux transpired using Fluental, Fe, Li, and Bi filters with thicknesses of 7.4, 3, 0.5, and 4 cm, respectively; as well as the epithermal to thermal neutron flux ratio was 161. Results demonstrated that the induced neutrons from a low energy and low current proton may be effective in tumor therapy using 208Pb moderator with average lethargy and also graphite reflector with low absorption cross section to keep the generated neutrons. Combination of spallation-based BNCT and proton therapy can be especially effective, if a high beam intensity cyclotron becomes available.

  6. Measurements of secondary neutrons producted from thick targets bombarded by heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kurosawa, T.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Nakao, N.; Shibata, T.; Uwamino, Y.; Nakanishi, N.; Fukumura, A.; Kumamoto, Y.

    1997-03-01

    We measured neutron angular and energy distributions from high energy heavy ions stopping in targets of carbon, aluminum, copper and lead at HIMAC. These spectra are much harder for the lighter target nucleus like carbon. This means that the momentum transfer in the forward direction from heavy ion beam to lighter nuclei is much higher than that to heavier nuclei. (author)

  7. Target screening effect on the pre-emission of neutrons from Li11 halo nuclei

    Science.gov (United States)

    Petrascu, M.; Constantinescu, A.; Cruceru, I.; Giurgiu, M.; Isbasescu, A.; Petrascu, H.; Bordeanu, C.; Serban, S.; Stoica, V.; Tanihata, I.; Lynch, W. G.; Famiano, M. A.; Lyuboshits, V. L.; Lyuboshits, V. V.; Ieki, K.

    2006-05-01

    For the first time to our knowledge the target screening effect on the pre-emission of halo neutrons from Li11 has been quantitatively analyzed. Our work has been performed in the 7.5 15 MeV neutron energy range. In this range the target nuclei are likely to behave as opaque, and therefore the sharp-cutoff calculations are most appropriate for the target screening determination. It has been observed that the ζ probability used in the sharp-cutoff calculations is an observable of the experiment, because it can be directly obtained from measured quantities, which are the number of single detected neutrons and the number of detected neutron pairs. The value of ζexp obtained this way in the case of a Si target appears to be close to the ζ value calculated for the Li11 halo radius RH=4.8 fm, independently determined in another experiment [Phys. Lett. B287, 307 (1992)]. This property also allows investigation of Borromean halo nuclei such as He6, Be14, and B17, for which RH was not yet measured. The calculated value within the present approach of the two-neutron pre-emission yield appears to be 3.5 times larger in the case of C12 than in the case of a Si target.

  8. Compact polarimetric SAR product and calibration considerations for target analysis

    Science.gov (United States)

    Sabry, Ramin

    2016-10-01

    Compact polarimetric (CP) data exploitation is currently of growing interest considering the new generation of such Synthetic Aperture Radar (SAR) systems. These systems offer target detection and classification capabilities comparable to those of polarimetric SARs (PolSAR) with less stringent requirements. A good example is the RADARSAT Constellation Mission (RCM). In this paper, some characteristic CP products are described and effects of CP mode deviation from ideal circular polarization transmit on classifications are modeled. The latter is important for operation of typical CP modes (e.g., RCM). The developed model can be used to estimate the ellipticity variation from CP measured data, and hence, calibrate the classification products.

  9. Preparation of radioactive rare earth targets for neutron capture study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G. G. (Geoffrey G.); Rogers, P. S. Z. (Pamela S. Z.); Palmer, P. D. (Phillip D.); Dry, D. E. (Donald E.); Rundberg, R. S. (Robert S.); Fowler, Malcolm M.; Wilhelmy, J. B. (Jerry B.)

    2002-01-01

    The understanding of thc details of nucleosynthesis in stars remains a great challenge. Though the basic mechanisms governing the processes have been known since the pioneering work of Burbidge, Burbidge, Fowler and Hoyle (l), we are now evolving into a condition where we can ask more specific questions. Of particular interest are the dynamics of the s ('slow') process. In this process the general condition is one in which sequential neutron captures occur at time scales long compared with the beta decay half lives of the capturing nuclides. The nucleosynthesis period for C or Ne burning stellar shells is believed to be in the year to few year time frame (2). This means that radionuclides with similar half lives to this burning period serve as 'branch point' nuclides. That is, there will be a competition between a capture to the next heavier isotope and a beta decay to the element of nexl higher atomic number. By understanding the abundances of these competing reactions we can learn about the dynamics of the nucleosynthesis process in the stellar medium. Crucial to this understanding is that we have a knowledge of the underlying neutron reaction cross sections on these unstable nuclides in the relevant stellar energy regions (neutrons of 0.1-100 KeV). Tm (1.9 years) and ls'Sm (90 ycws) have decay properties that permit their handling in an open fume hood. These Iwo were therefore selected to be the first radionuclides for neutron capture study in what will be an ongoing effort.

  10. Physics considerations in targeted anticancer drug delivery by magnetoelectric nanoparticles

    Science.gov (United States)

    Stimphil, Emmanuel; Nagesetti, Abhignyan; Guduru, Rakesh; Stewart, Tiffanie; Rodzinski, Alexandra; Liang, Ping; Khizroev, Sakhrat

    2017-06-01

    In regard to cancer therapy, magnetoelectric nanoparticles (MENs) have proven to be in a class of its own when compared to any other nanoparticle type. Like conventional magnetic nanoparticles, they can be used for externally controlled drug delivery via application of a magnetic field gradient and image-guided delivery. However, unlike conventional nanoparticles, due to the presence of a non-zero magnetoelectric effect, MENs provide a unique mix of important properties to address key challenges in modern cancer therapy: (i) a targeting mechanism driven by a physical force rather than antibody matching, (ii) a high-specificity delivery to enhance the cellular uptake of therapeutic drugs across the cancer cell membranes only, while sparing normal cells, (iii) an externally controlled mechanism to release drugs on demand, and (iv) a capability for image guided precision medicine. These properties separate MEN-based targeted delivery from traditional biotechnology approaches and lay a foundation for the complementary approach of technobiology. The biotechnology approach stems from the underlying biology and exploits bioinformatics to find the right therapy. In contrast, the technobiology approach is geared towards using the physics of molecular-level interactions between cells and nanoparticles to treat cancer at the most fundamental level and thus can be extended to all the cancers. This paper gives an overview of the current state of the art and presents an ab initio model to describe the underlying mechanisms of cancer treatment with MENs from the perspective of basic physics.

  11. Practical considerations for therapies targeting the prostacyclin pathway

    Directory of Open Access Journals (Sweden)

    Harrison W. Farber

    2016-12-01

    Full Text Available Therapies that target the prostacyclin pathway play a key role in the treatment of both early- and late-stage pulmonary arterial hypertension, and provide significant clinical benefits for patients. A number of agents have been approved, which are administered via intravenous, subcutaneous, inhaled or oral routes. The use of these therapies is associated with practical challenges, relating to the need for up-titration and their routes of administration. We discuss here a number of measures that can be taken to support patients and healthcare professionals in order to address the complexities of using these therapies and to encourage compliance. Providing patients with timely information and education, together with practical advice on managing their medication and associated equipment, assists patients with day-to-day management of therapy. Referral to patient associations and support groups can be of further benefit. With an effective management plan and an experienced multidisciplinary team, the use of therapies that target the prostacyclin pathway can be optimised.

  12. High-power liquid-lithium jet target for neutron production

    CERN Document Server

    Halfon, S; Kijel, D; Paul, M; Berkovits, D; Eliyahu, I; Feinberg, G; Friedman, M; Hazenshprung, N; Mardor, I; Nagler, A; Shimel, G; Tessler, M; Silverman, I

    2013-01-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the 7Li(p,n)7Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy (BNCT). The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm3) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the 7Li(p,n) neutron yield, energy distribution and angular distribution. Liquid lithium is circulated through the target loop at ~200oC and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can diss...

  13. A multi-layered active target for the study of neutron-unbound nuclides at NSCL

    Science.gov (United States)

    Freeman, Jessica; Gueye, Paul; Redpath, Thomas; MoNA Collaboration

    2017-01-01

    The characteristics of neutron-unbound nuclides were investigated using a multi-layered Si/Be active target designed for use with the MoNA/LISA setup at the National Superconducting Cyclotron (NSCL). The setup consists of the MoNA/LISA arrays (for neutron detection) and a superconducting sweeper magnet (for charged separation) to identify products following the decay of neutron unbound states. The segmented target consisted of three 700 mg/cm2 beryllium targets and four 0.14 mm thick 62x62 mm2 silicon detectors. As a commissioning experiment for the target the decay of two-neutron unbound 26O populated in a one-proton removal reaction from a radioactive 27F beam was performed. The 27F secondary radioactive beam from the NSCL's Coupled Cyclotron Facility was produced from the fragmentation of a 140 MeV/u 48Ca beam incident on a thick beryllium target and then cleanly selected by the A1900 fragment separator. The energy loss and position spectra of the incoming beam and reaction products were used to calibrate the Silicon detectors to within 1.5% in both energy and position. A dedicated Geant4 model of the target was developed to simulate the energy loss within the target. A description of the experimental setup, simulation work, and energy and position calibration will be presented. DoE/NNSA - DE-NA0000979.

  14. Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-20

    -state heat fluxes of 5–20 MW/m2 and ion fluxes up to 1024 m-2s-1. Since PFCs will have to withstand neutron irradiation displacement damage up to 50 dpa, the target station design must accommodate radioactive specimens (materials to be irradiated in HFIR or at SNS) to enable investigations of the impact of neutron damage on materials. Therefore, the system will have to be able to install and extract irradiated specimens using equipment and methods to avoid sample modification, control contamination, and minimize worker dose. Included in the design considerations will be an assessment of all the steps between neutron irradiation and post-exposure materials examination/characterization, as well as an evaluation of the facility hazard categorization. In particular, the factors associated with the acquisition of radioactive specimens and their preparation, transportation, experimental configuration at the plasma-specimen interface, post-plasma-exposure sample handling, and specimen preparation will be evaluated.

  15. A neutron production target for ESS based upon the Canned-rods concept

    Energy Technology Data Exchange (ETDEWEB)

    Ghiglino, A., E-mail: angeloglinovoa@gmail.com [ESS-BILBAO, Parque Tecnológico Bizkaia, Laida Bidea, Edificio 207 B Planta Baja, 48160 Derio (Spain); Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/José Gutiérrez Abascal, 2, 28006 Madrid (Spain); Terrón, S. [ESS-BILBAO, Parque Tecnológico Bizkaia, Laida Bidea, Edificio 207 B Planta Baja, 48160 Derio (Spain); Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/José Gutiérrez Abascal, 2, 28006 Madrid (Spain); Thomsen, K. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Wolters, J. [Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Magán, M.; Martínez, F.; Vicente, P.J. de; Vivanco, R.; Sordo, F. [ESS-BILBAO, Parque Tecnológico Bizkaia, Laida Bidea, Edificio 207 B Planta Baja, 48160 Derio (Spain); Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/José Gutiérrez Abascal, 2, 28006 Madrid (Spain); Butzek, M. [Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Perlado, J.M. [Instituto de Fusión Nuclear - UPM, ETS Ingenieros Industriales, C/José Gutiérrez Abascal, 2, 28006 Madrid (Spain); Bermejo, F.J. [Instituto de Estructura de la Materia, IEM-CSIC, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid (Spain)

    2014-08-21

    The neutron production targets operating within the present day spallation neutron sources in the MW power range are either based on water-cooled solid state devices such as that implemented at the SINQ source at PSI or liquid metal loops such as those installed at SNS and MLSF. Here we describe a water-cooled rotating solid target as an option for the 5 MW ESS project as an alternative to the current design based upon a helium-cooled solid rotating target. Implementation of the proposed option would provide comparable neutronic performance to that of the gas-cooled concept and furthermore, it would involve a relatively straightforward adaptation of the current ESS baseline geometry.

  16. A Multi-layered target for the Study of Neutron-Unbound Nuclei

    Science.gov (United States)

    Gueye, Paul; Frank, Nathan; Thoennessen, Michael

    2013-04-01

    The MoNA/LISA setup at the National Superconducting Cyclotron Laboratory at Michigan State University has provided an avenue to study the nuclear structure of unbound states/nuclei at and beyond the neutron drip line for the past decade using secondary beams from the Coupled Cyclotron Facility. A new multi-layered Si/Be active target is planned to be built to specifically study neutron unbound nuclei. In these experiments the decay energy is reconstructed from fragment-neutron coincidence measurements which are typically low in count rate. The multi-layered target will allow the use of thicker targets to increase the reaction rates, thus enabling to study currently out of reach nuclei such as 21C, 23C, and 24N. A description of the new setup and physics impact will be discussed.

  17. Laser-driven neutron production from bulk and pitcher-catcher targets

    Science.gov (United States)

    Maksimchuk, Anatoly; Willingale, L.; Matsuoka, T.; Thomas, A. G. R.; Krushelnick, K.; Petrov, G. M.; Davis, J.; Ovchinnikov, V. M.; Freeman, R. R.; Joglekar, A.; Murphy, C. D.; Woerkom, L. Van

    2010-11-01

    As an important step in the development of the highly directional compact neutron source from the reaction ^7Li(d,xn) [1] we have studied the laser-driven fusion neutron production d(d,n)^3He from bulk deuterated plastic targets and compared it to a pitcher-catcher target method using the same laser and detector arrangement. For laser intensities of up to I = 3.10^19 Wcm^2 it was found that the bulk targets produced a high yield (5.10^4 neutrons/steradian) beamed preferentially in the laser propagation direction. The inhibition of the deuteron acceleration by a proton rich contamination layer is likely to significantly reduce the pitcher-catcher neutron production. Two-dimensional particle-in-cell simulations were performed to model the deuteron beam acceleration, the results of which were coupled to a Monte Carlo code to calculate the expected neutron beam properties. Numerical analysis suggests the pitcher-catcher targets would become more efficient at higher laser intensities. This work was supported by DTRA and the NRL. [1] J. Davis et al., PPCF 52, 045015 (2010).

  18. Characterization of 235U Targets for the Development of a Secondary Neutron Fluence Standard

    Science.gov (United States)

    Heyse, J.; Anastasiou, M.; Eykens, R.; Moens, A.; Plompen, A. J. M.; Schillebeeckx, P.; Sibbens, G.; Vanleeuw, D.; Wynants, R.

    2014-05-01

    The MetroFission project, a Joint Research Project within the European Metrology Research Program (EMRP), aims at addressing a number of metrological problems involved in the design of proposed Generation IV nuclear reactors. As part of this project a secondary neutron fluence standard is being developed and tested at the neutron time-of-flight facility GELINA of the JRC Institute for Reference Materials and Measurements (IRMM). This secondary standard will help to reach the neutron cross section measurement uncertainties required for the design of new generation power plants and fuel cycles. Such a neutron fluence device contains targets for which the neutron induced cross section is considered to be a standard. A careful preparation and characterization of these samples is an essential part of its development. In this framework a set of 235U targets has been produced by vacuum deposition of UF4 on aluminum backings by the target preparation laboratory at IRMM. These targets have been characterized for both their total mass and mass distribution over the sample area.

  19. Secondary neutron-production cross sections from heavy-ioninteractions in composite targets.

    Energy Technology Data Exchange (ETDEWEB)

    Heilbronn, L.; Iwata, Y.; Iwase,H.; Murakami, T.; Sato, H.; Nakamura, T.; Ronningen, R.M.; Ieki, K.; Gudowska, I.; Sobolevsky, N.

    2005-12-19

    Secondary neutron-production cross-sections have been measured from interactions of 290 MeV/nucleon C and 600 MeV/nucleon Ne in a target composed of simulated Martian regolith and polyethylene, and from 400 MeV/nucleon Ne interactions in wall material from the International Space Station. The data were measured between 5 and 80 deg in the laboratory. We report the double-differential cross sections, angular distributions, and total neutron-production cross sections from all three systems. The spectra from all three systems exhibit behavior previously reported in other heavy-ion, neutron production experiments; namely, a peak at forward angles near the energy corresponding to the beam velocity, with the remaining spectra generated by pre-equilibrium and equilibrium processes. The double differential cross sections are fitted with a moving-source parameterization. Also reported are the data without corrections for neutron flux attenuation in the target and other intervening materials, and for neutron production in non-target materials near the target position. These uncorrected spectra are compared with SHIELD-HIT and PHITS transport model calculations. The transport model calculations reproduce the spectral shapes well, but, on average, underestimate the magnitudes of the cross sections.

  20. Consideration of a ultracold neutron source in two-dimensional cylindrical geometry by taking simulated boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Gheisari, R., E-mail: gheisari@pgu.ac.ir [Physics Department, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Nuclear Energy Research Center, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Firoozabadi, M. M.; Mohammadi, H. [Department of Physics, University of Birjand, Birjand 97175 (Iran, Islamic Republic of)

    2014-01-15

    A new idea to calculate ultracold neutron (UCN) production by using Monte Carlo simulation method to calculate the cold neutron (CN) flux and an analytical approach to calculate the UCN production from the simulated CN flux was given. A super-thermal source (UCN source) was modeled based on an arrangement of D{sub 2}O and solid D{sub 2} (sD{sub 2}). The D{sub 2}O was investigated as the neutron moderator, and sD{sub 2} as the converter. In order to determine the required parameters, a two-dimensional (2D) neutron balance equation written in Matlab was combined with the MCNPX simulation code. The 2D neutron-transport equation in cylindrical (ρ − z) geometry was considered for 330 neutron energy groups in the sD{sub 2}. The 2D balance equation for UCN and CN was solved using simulated CN flux as boundary value. The UCN source dimensions were calculated for the development of the next UCN source. In the optimal condition, the UCN flux and the UCN production rate (averaged over the sD{sub 2} volume) equal to 6.79 × 10{sup 6} cm{sup −2}s{sup −1} and 2.20 ×10{sup 5} cm{sup −3}s{sup −1}, respectively.

  1. Consideration of a ultracold neutron source in two-dimensional cylindrical geometry by taking simulated boundaries

    Science.gov (United States)

    Gheisari, R.; Firoozabadi, M. M.; Mohammadi, H.

    2014-01-01

    A new idea to calculate ultracold neutron (UCN) production by using Monte Carlo simulation method to calculate the cold neutron (CN) flux and an analytical approach to calculate the UCN production from the simulated CN flux was given. A super-thermal source (UCN source) was modeled based on an arrangement of D2O and solid D2 (sD2). The D2O was investigated as the neutron moderator, and sD2 as the converter. In order to determine the required parameters, a two-dimensional (2D) neutron balance equation written in Matlab was combined with the MCNPX simulation code. The 2D neutron-transport equation in cylindrical (ρ - z) geometry was considered for 330 neutron energy groups in the sD2. The 2D balance equation for UCN and CN was solved using simulated CN flux as boundary value. The UCN source dimensions were calculated for the development of the next UCN source. In the optimal condition, the UCN flux and the UCN production rate (averaged over the sD2 volume) equal to 6.79 × 106 cm-2s-1 and 2.20 ×105 cm-3s-1, respectively.

  2. Consideration of a ultracold neutron source in two-dimensional cylindrical geometry by taking simulated boundaries

    Directory of Open Access Journals (Sweden)

    R. Gheisari

    2014-01-01

    Full Text Available A new idea to calculate ultracold neutron (UCN production by using Monte Carlo simulation method to calculate the cold neutron (CN flux and an analytical approach to calculate the UCN production from the simulated CN flux was given. A super-thermal source (UCN source was modeled based on an arrangement of D2O and solid D2 (sD2. The D2O was investigated as the neutron moderator, and sD2 as the converter. In order to determine the required parameters, a two-dimensional (2D neutron balance equation written in Matlab was combined with the MCNPX simulation code. The 2D neutron-transport equation in cylindrical (ρ − z geometry was considered for 330 neutron energy groups in the sD2. The 2D balance equation for UCN and CN was solved using simulated CN flux as boundary value. The UCN source dimensions were calculated for the development of the next UCN source. In the optimal condition, the UCN flux and the UCN production rate (averaged over the sD2 volume equal to 6.79 × 106 cm−2s−1 and 2.20 ×105 cm−3s−1, respectively.

  3. Preliminary shielding analysis in support of the CSNS target station shutter neutron beam stop design

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bin; CHEN Yi-Xue; WANG Wei-Jin; YANG Shou-Hai; WU Jun; YIN Wen; LIANG Tian-Jiao; JIA Xue-Jun

    2011-01-01

    The construction of China Spallation Neutron Source (CSNS) has been initiated in Dongguan,Guangdong, China.Thus a detailed radiation transport analysis of the shutter neutron beam stop is of vital importance. The analyses are performed using the coupled Monte Carlo and multi-dimensional discrete ordinates method. The target of calculations is to optimize the neutron beamline shielding design to guarantee personal safety and minimize cost. Successful elimination of the primary ray effects via the two-dimensional uncollided flux and the first collision source methodology is also illustrated. Two-dimensional dose distribution is calculated. The dose at the end of the neutron beam line is less than 2.5μSv/h. The models have ensured that the doses received by the hall staff members are below the standard limit required.

  4. Measurement of neutron energy spectra and neutron dose rates from {sup 7}Li(p,n){sup 7}Be reaction induced on thin LiF target

    Energy Technology Data Exchange (ETDEWEB)

    Atanackovic, Jovica, E-mail: atanacjz@gmail.com [Ontario Power Generation, Whitby, ON, Canada L1N 9E3 (Canada); Atomic Energy of Canada Limited, Chalk River Laboratories, Chalk River, Canada K0J 1J0 (Canada); Matysiak, Witold [University of Florida Proton Therapy Institute, Jacksonville, FL 32206 (United States); Dubeau, Jacques; Witharana, Sampath [DETEC, Gatineau, QC, Canada J8T 4J1 (Canada); Waker, Anthony [University of Ontario Institute of Technology, Oshawa, ON, Canada L1H 7K4 (Canada)

    2015-02-21

    The measurements of neutron energy spectra and neutron dose rates were performed using the KN Van de Graaff accelerator, located at the McMaster University Accelerator Laboratory (MAL). Protons were accelerated on the thin lithium fluoride (LiF) target and produced mono-energetic neutrons which were measured using three different spectrometers: Bonner Sphere Spectrometer (BSS), Nested Neutron Spectrometer (NNS), and Rotational Proton Recoil Spectrometer (ROSPEC). The purpose of this work is (1) measurement and quantification of low energy accelerator neutron fields in terms of neutron fluence and dose, (2) comparison of results obtained by three different instruments, (3) comparison of measurements with Monte Carlo simulations based on theoretical neutron yields from {sup 7}Li(p,n){sup 7}Be nuclear reaction, and (4) comparison of results obtained using different neutron spectral unfolding methods. The nominal thickness of the LiF target used in the experiment was 50μg/cm{sup 2}, which corresponds to the linear thickness of 0.19μm and results in approximately 6 keV energy loss for the proton energies used in the experiment (2.2, 2.3, 2.4 and 2.5 MeV). For each of the proton energies, neutron fluence per incident proton charge was measured and several dosimetric quantities of interest in radiation protection were derived. In addition, theoretical neutron yield calculations together with the results of Monte Carlo (MCNP) modeling of the neutron spectra are reported. Consistent neutron fluence spectra were obtained with three detectors and good agreement was observed between theoretically calculated and measured neutron fluences and derived dosimetric quantities for investigated proton energies at 2.3, 2.4 and 2.5 MeV. In the case of 2.2 MeV, some plausibly explainable discrepancies were observed.

  5. Design of the Next Generation Target at the Lujan Neutron Scattering Center, LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Ferres, Laurent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); National Graduate School of Engineering and Research Center (ENSICAEN), Caen (France)

    2016-08-03

    Los Alamos National Laboratory (LANL) supports scientific research in many diverse fields such as biology, chemistry, and nuclear science. The Laboratory was established in 1943 during the Second World War to develop nuclear weapons. Today, LANL is one of the largest laboratories dedicated to nuclear defense and operates an 800 MeV proton linear accelerator for basic and applied research including: production of high- and low-energy neutrons beams, isotope production for medical applications and proton radiography. This accelerator is located at the Los Alamos Neutron Science Center (LANSCE). The work performed involved the redesign of the target for the low-energy neutron source at the Lujan Neutron Scattering Center, which is one of the facilities built around the accelerator. The redesign of the target involves modeling various arrangements of the moderator-reflector-shield for the next generation neutron production target. This is done using Monte Carlo N-Particle eXtended (MCNPX), and ROOT analysis framework, a C++ based-software, to analyze the results.

  6. High-flux neutron source based on a liquid-lithium target

    Science.gov (United States)

    Halfon, S.; Feinberg, G.; Paul, M.; Arenshtam, A.; Berkovits, D.; Kijel, D.; Nagler, A.; Eliyahu, I.; Silverman, I.

    2013-04-01

    A prototype compact Liquid Lithium Target (LiLiT), able to constitute an accelerator-based intense neutron source, was built. The neutron source is intended for nuclear astrophysical research, boron neutron capture therapy (BNCT) in hospitals and material studies for fusion reactors. The LiLiT setup is presently being commissioned at Soreq Nuclear research Center (SNRC). The lithium target will produce neutrons through the 7Li(p,n)7Be reaction and it will overcome the major problem of removing the thermal power generated by a high-intensity proton beam, necessary for intense neutron flux for the above applications. The liquid-lithium loop of LiLiT is designed to generate a stable lithium jet at high velocity on a concave supporting wall with free surface toward the incident proton beam (up to 10 kW). During off-line tests, liquid lithium was flown through the loop and generated a stable jet at velocity higher than 5 m/s on the concave supporting wall. The target is now under extensive test program using a high-power electron-gun. Up to 2 kW electron beam was applied on the lithium flow at velocity of 4 m/s without any flow instabilities or excessive evaporation. High-intensity proton beam irradiation will take place at SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator currently in commissioning at SNRC.

  7. Spectroscopy of neutron rich nuclei using cold neutron induced fission of actinide targets at the ILL: The EXILL campaign

    Directory of Open Access Journals (Sweden)

    Blanc A.

    2013-12-01

    Full Text Available One way to explore exotic nuclei is to study their structure by performing γ-ray spectroscopy. At the ILL, we exploit a high neutron flux reactor to induce the cold fission of actinide targets. In this process, fission products that cannot be accessed using standard spontaneous fission sources are produced with a yield allowing their detailed study using high resolution γ-ray spectroscopy. This is what was pursued at the ILL with the EXILL (for EXOGAM at the ILL campaign. In the present work, the EXILL setup and performance will be presented.

  8. Prototype Spallation Neutron Source Rotating Target Assembly Final Test Report

    Energy Technology Data Exchange (ETDEWEB)

    McManamy, Thomas J [ORNL; Graves, Van [Oak Ridge National Laboratory (ORNL); Garmendia, Amaia Zarraoa [IDOM Bilbao; Sorda, Fernando [ESS Bilbao; Etxeita, Borja [IDOM Bilbao; Rennich, Mark J [ORNL

    2011-01-01

    A full-scale prototype of an extended vertical shaft, rotating target assembly based on a conceptual target design for a 1 to 3-MW spallation facility was built and tested. Key elements of the drive/coupling assembly implemented in the prototype include high integrity dynamic face seals, commercially available bearings, realistic manufacturing tolerances, effective monitoring and controls, and fail-safe shutdown features. A representative target disk suspended on a 3.5 meter prototypical shaft was coupled with the drive to complete the mechanical tests. Successful operation for 5400 hours confirmed the overall mechanical feasibility of the extended vertical shaft rotating target concept. The prototype system showed no indications of performance deterioration and the equipment did not require maintenance or relubrication.

  9. THERMAL HYDRAULIC ANALYSIS OF A LIQUID-METAL-COOLED NEUTRON SPALLATION TARGET

    Energy Technology Data Exchange (ETDEWEB)

    W. GREGORY; R. MARTIN; T. VALACHOVIC

    2000-07-01

    We have carried out numerical simulations of the thermal hydraulic behavior of a neutron spallation target where liquid metal lead-bismuth serves as both coolant and as a neutron spallation source. The target is one of three designs provided by the Institute of Physics and Power Engineering (IPPE) in Russia. This type of target is proposed for Accelerator-driven Transmutation of Waste (ATW) to eliminate plutonium from hazardous fission products. The thermal hydraulic behavior was simulated by use of a commercial CFD computer code called CFX. Maximum temperatures in the diaphragm window and in the liquid lead were determined. In addition the total pressure drop through the target was predicted. The results of the CFX analysis were close to those results predicted by IPPE in their preliminary analysis.

  10. A Targeted Search for Point Sources of EeV Neutrons

    CERN Document Server

    Aab, A; Aglietta, M; Ahlers, M; Ahn, E J; Samarai, I Al; Albuquerque, I F M; Allekotte, I; Allen, J; Allison, P; Almela, A; Castillo, J Alvarez; Alvarez-Muñiz, J; Batista, R Alves; Ambrosio, M; Aminaei, A; Anchordoqui, L; Andringa, S; Aramo, C; Arqueros, F; Asorey, H; Assis, P; Aublin, J; Ave, M; Avenier, M; Avila, G; Badescu, A M; Barber, K B; Bäuml, J; Baus, C; Beatty, J J; Becker, K H; Bellido, J A; Berat, C; Bertou, X; Biermann, P L; Billoir, P; Blanco, F; Blanco, M; Bleve, C; Blümer, H; Boháčová, M; Boncioli, D; Bonifazi, C; Bonino, R; Borodai, N; Brack, J; Brancus, I; Brogueira, P; Brown, W C; Buchholz, P; Bueno, A; Buscemi, M; Caballero-Mora, K S; Caccianiga, B; Caccianiga, L; Candusso, M; Caramete, L; Caruso, R; Castellina, A; Cataldi, G; Cazon, L; Cester, R; Chavez, A G; Cheng, S H; Chiavassa, A; Chinellato, J A; Chudoba, J; Cilmo, M; Clay, R W; Cocciolo, G; Colalillo, R; Collica, L; Coluccia, M R; Conceição, R; Contreras, F; Cooper, M J; Coutu, S; Covault, C E; Criss, A; Cronin, J; Curutiu, A; Dallier, R; Daniel, B; Dasso, S; Daumiller, K; Dawson, B R; de Almeida, R M; De Domenico, M; de Jong, S J; Neto, J R T de Mello; De Mitri, I; de Oliveira, J; de Souza, V; del Peral, L; Deligny, O; Dembinski, H; Dhital, N; Di Giulio, C; Di Matteo, A; Diaz, J C; Castro, M L Díaz; Diep, P N; Diogo, F; Dobrigkeit, C; Docters, W; D'Olivo, J C; Dong, P N; Dorofeev, A; Dova, M T; Ebr, J; Engel, R; Erdmann, M; Erfani, M; Escobar, C O; Espadanal, J; Etchegoyen, A; Luis, P Facal San; Falcke, H; Fang, K; Farrar, G; Fauth, A C; Fazzini, N; Ferguson, A P; Fernandes, M; Fick, B; Figueira, J M; Filevich, A; Filipčič, A; Fox, B D; Fratu, O; Fröhlich, U; Fuchs, B; Fuji, T; Gaior, R; García, B; Roca, S T Garcia; Garcia-Gamez, D; Garcia-Pinto, D; Garilli, G; Bravo, A Gascon; Gate, F; Gemmeke, H; Ghia, P L; Giaccari, U; Giammarchi, M; Giller, M; Glaser, C; Glass, H; Albarracin, F Gomez; Berisso, M Gómez; Vitale, P F Gómez; Gonçalves, P; Gonzalez, J G; Gookin, B; Gorgi, A; Gorham, P; Gouffon, P; Grebe, S; Griffith, N; Grillo, A F; Grubb, T D; Guardincerri, Y; Guarino, F; Guedes, G P; Hansen, P; Harari, D; Harrison, T A; Harton, J L; Hasankiadeh, Q D; Haungs, A; Hebbeker, T; Heck, D; Heimann, P; Herve, A E; Hill, G C; Hojvat, C; Hollon, N; Holt, E; Homola, P; Hörandel, J R; Horvath, P; Hrabovský, M; Huber, D; Huege, T; Insolia, A; Isar, P G; Islo, K; Jandt, I; Jansen, S; Jarne, C; Josebachuili, M; Kääpä, A; Kambeitz, O; Kampert, K H; Kasper, P; Katkov, I; Kégl, B; Keilhauer, B; Keivani, A; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Krause, R; Krohm, N; Krömer, O; Kruppke-Hansen, D; Kuempel, D; Kunka, N; La Rosa, G; LaHurd, D; Latronico, L; Lauer, R; Lauscher, M; Lautridou, P; Coz, S Le; Leão, M S A B; Lebrun, D; Lebrun, P; de Oliveira, M A Leigui; Letessier-Selvon, A; Lhenry-Yvon, I; Link, K; López, R; Agüera, A Lopez; Louedec, K; Bahilo, J Lozano; Lu, L; Lucero, A; Ludwig, M; Lyberis, H; Maccarone, M C; Malacari, M; Maldera, S; Maller, J; Mandat, D; Mantsch, P; Mariazzi, A G; Marin, V; Mariş, I C; Marsella, G; Martello, D; Martin, L; Martinez, H; Bravo, O Martínez; Martraire, D; Meza, J J Masías; Mathes, H J; Mathys, S; Matthews, A J; Matthews, J; Matthiae, G; Maurel, D; Maurizio, D; Mayotte, E; Mazur, P O; Medina, C; Medina-Tanco, G; Melissas, M; Melo, D; Menichetti, E; Menshikov, A; Messina, S; Meyhandan, R; Mićanović, S; Micheletti, M I; Middendorf, L; Minaya, I A; Miramonti, L; Mitrica, B; Molina-Bueno, L; Mollerach, S; Monasor, M; Ragaigne, D Monnier; Montanet, F; Morello, C; Moreno, J C; Mostafá, M; Moura, C A; Muller, M A; Müller, G; Münchmeyer, M; Mussa, R; Navarra, G; Navas, S; Necesal, P; Nellen, L; Nelles, A; Neuser, J; Niechciol, M; Niemietz, L; Niggemann, T; Nitz, D; Nosek, D; Novotny, V; Nožka, L; Ochilo, L; Olinto, A; Oliveira, M; Ortiz, M; Pacheco, N; Selmi-Dei, D Pakk; Palatka, M; Pallotta, J; Palmieri, N; Papenbreer, P; Parente, G; Parra, A; Pastor, S; Paul, T; Pech, M; Pȩkala, J; Pelayo, R; Pepe, I M; Perrone, L; Pesce, R; Petermann, E; Peters, C; Petrera, S; Petrolini, A; Petrov, Y; Piegaia, R; Pierog, T; Pieroni, P; Pimenta, M; Pirronello, V; Platino, M; Plum, M; Porcelli, A; Porowski, C; Privitera, P; Prouza, M; Purrello, V; Quel, E J; Querchfeld, S; Quinn, S; Rautenberg, J; Ravel, O; Ravignani, D; Revenu, B; Ridky, J; Riggi, S; Risse, M; Ristori, P; Rizi, V; Roberts, J; de Carvalho, W Rodrigues; Cabo, I Rodriguez; Fernandez, G Rodriguez; Rojo, J Rodriguez; Rodríguez-Frías, M D; Ros, G; Rosado, J; Rossler, T; Roth, M; Roulet, E; Rovero, A C; Rühle, C; Saffi, S J; Saftoiu, A; Salamida, F; Salazar, H; Greus, F Salesa; Salina, G; Sánchez, F; Sanchez-Lucas, P; Santo, C E; Santos, E; Santos, E M; Sarazin, F; Sarkar, B; Sarmento, R; Sato, R; Scharf, N; Scherini, V; Schieler, H; Schiffer, P; Schmidt, A; Scholten, O; Schoorlemmer, H; Schovánek, P; Schulz, A; Schulz, J; Sciutto, S J; Segreto, A; Settimo, M; Shadkam, A; Shellard, R C; Sidelnik, I; Sigl, G; Sima, O; Śmiałkowski, A; Šmída, R; Snow, G R; Sommers, P; Sorokin, J; Squartini, R; Srivastava, Y N; Stanič, S; Stapleton, J; Stasielak, J; Stephan, M; Stutz, A; Suarez, F; Suomijärvi, T; Supanitsky, A D; Sutherland, M S; Swain, J; Szadkowski, Z; Szuba, M; Taborda, O A; Tapia, A; Tartare, M; Thao, N T; Theodoro, V M; Tiffenberg, J; Timmermans, C; Peixoto, C J Todero; Toma, G; Tomankova, L; Tomé, B; Tonachini, A; Elipe, G Torralba; Machado, D Torres; Travnicek, P; Trovato, E; Tueros, M; Ulrich, R; Unger, M; Urban, M; Galicia, J F Valdés; Valiño, I; Valore, L; van Aar, G; Berg, A M van den; van Velzen, S; van Vliet, A; Varela, E; Cárdenas, B Vargas; Varner, G; Vázquez, J R; Vázquez, R A; Veberič, D; Verzi, V; Vicha, J; Videla, M; Villaseñor, L; Vlcek, B; Wahlberg, H; Wainberg, O; Walz, D; Watson, A A; Weber, M; Weidenhaupt, K; Weindl, A; Werner, F; Whelan, B J; Widom, A; Wiencke, L; Wilczyńska, B; Wilczyński, H; Will, M; Williams, C; Winchen, T; Wittkowski, D; Wundheiler, B; Wykes, S; Yamamoto, T; Yapici, T; Younk, P; Yuan, G; Yushkov, A; Zamorano, B; Zas, E; Zavrtanik, D; Zavrtanik, M; Zaw, I; Zepeda, A; Zhou, J; Zhu, Y; Silva, M Zimbres; Ziolkowski, M

    2014-01-01

    A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine "target sets", in addition to the search for a neutron flux from the Galactic Center or from the Galactic Plane. Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay. These searches do not find evidence for a neutron flux from any class of candidate sources. Tabulated results give the combined p-value for each class, with and without the weights, and also the flux upper limit for the most significant candidate source within each class. These limits on fluxes of neutrons significantly constrain models of EeV proton emission from non-transient discrete sources in the Galaxy.

  11. A Targeted Search for Point Sources of EeV Neutrons

    Science.gov (United States)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fox, B. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Fuji, T.; Gaior, R.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q. D.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Islo, K.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, A. J.; Matthews, J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Ochilo, L.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Peķala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Peters, C.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tartare, M.; Thao, N. T.; Theodoro, V. M.; Tiffenberg, J.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Whelan, B. J.; Widom, A.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Auger Collaboration101, The Pierre

    2014-07-01

    A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine "target sets," in addition to the search for a neutron flux from the Galactic center or from the Galactic plane. Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay. These searches do not find evidence for a neutron flux from any class of candidate sources. Tabulated results give the combined p-value for each class, with and without the weights, and also the flux upper limit for the most significant candidate source within each class. These limits on fluxes of neutrons significantly constrain models of EeV proton emission from non-transient discrete sources in the Galaxy.

  12. High-power liquid-lithium target prototype for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Bisyakoev, M; Eliyahu, I; Feinberg, G; Hazenshprung, N; Kijel, D; Nagler, A; Silverman, I

    2011-12-01

    A prototype of a compact Liquid-Lithium Target (LiLiT), which will possibly constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals, was built. The LiLiT setup is presently being commissioned at Soreq Nuclear Research Center (SNRC). The liquid-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 generated using a high-intensity proton beam (>10 kW), necessary for sufficient neutron flux. In off-line circulation tests, the liquid-lithium loop generated a stable lithium jet at high velocity, on a concave supporting wall; the concept will first be tested using a high-power electron beam impinging on the lithium jet. High intensity proton beam irradiation (1.91-2.5 MeV, 2-4 mA) will take place at Soreq Applied Research Accelerator Facility (SARAF) superconducting linear accelerator currently in construction at SNRC. Radiological risks due to the (7)Be produced in the reaction were studied and will be handled through a proper design, including a cold trap and appropriate shielding. A moderator/reflector assembly is planned according to a Monte Carlo simulation, to create a neutron spectrum and intensity maximally effective to the treatment and to reduce prompt gamma radiation dose risks.

  13. A TARGETED SEARCH FOR POINT SOURCES OF EeV NEUTRONS

    Energy Technology Data Exchange (ETDEWEB)

    Aab, A. [Universität Siegen, Siegen (Germany); Abreu, P.; Andringa, S. [Laboratório de Instrumentação e Física Experimental de Partículas-LIP and Instituto Superior Técnico-IST, Universidade de Lisboa-UL (Portugal); Aglietta, M. [Osservatorio Astrofisico di Torino (INAF), Università di Torino and Sezione INFN, Torino (Italy); Ahlers, M. [University of Wisconsin, Madison, WI (United States); Ahn, E. J. [Fermilab, Batavia, IL (United States); Al Samarai, I. [Institut de Physique Nucléaire d' Orsay (IPNO), Université Paris 11, CNRS-IN2P3, Orsay (France); Albuquerque, I. F. M. [Universidade de São Paulo, Instituto de Física, São Paulo, SP (Brazil); Allekotte, I. [Centro Atómico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Allen, J. [New York University, New York, NY (United States); Allison, P. [Ohio State University, Columbus, OH (United States); Almela, A. [Universidad Tecnológica Nacional-Facultad Regional Buenos Aires, Buenos Aires (Argentina); Castillo, J. Alvarez [Universidad Nacional Autonoma de Mexico, Mexico, D. F. (Mexico); Alvarez-Muñiz, J. [Universidad de Santiago de Compostela (Spain); Batista, R. Alves [Universität Hamburg, Hamburg (Germany); Ambrosio, M.; Aramo, C. [Università di Napoli " Federico II" and Sezione INFN, Napoli (Italy); Aminaei, A. [IMAPP, Radboud University Nijmegen (Netherlands); Anchordoqui, L. [University of Wisconsin, Milwaukee, WI (United States); Arqueros, F. [Universidad Complutense de Madrid, Madrid (Spain); Collaboration: Pierre Auger Collaboration101; and others

    2014-07-10

    A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine ''target sets'', in addition to the search for a neutron flux from the Galactic center or from the Galactic plane. Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay. These searches do not find evidence for a neutron flux from any class of candidate sources. Tabulated results give the combined p-value for each class, with and without the weights, and also the flux upper limit for the most significant candidate source within each class. These limits on fluxes of neutrons significantly constrain models of EeV proton emission from non-transient discrete sources in the Galaxy.

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

    Science.gov (United States)

    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.

  15. The study of neutron spectra in water bath from Pb target irradiated by 250MeV/u protons

    CERN Document Server

    Li, Yanyan; Ju, Yongqin; Ma, Fei; Zhang, Hongbin; Chen, Liang; Ge, Honglin; Luo, Peng; Zhou, Bin; Zhang, Yanbin; Li, Jianyang; Xu, Junkui; Wang, Songlin; Yang, Yongwei; Yang, Lei

    2014-01-01

    The spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with Cd cover. According to the measured activities of the foils, the neutron flux at different resonance energy were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code.

  16. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

    Science.gov (United States)

    Gallmeier, F. X.; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L.

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm2 to 20 × 20 mm2. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  17. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station.

    Science.gov (United States)

    Gallmeier, F X; Lu, W; Riemer, B W; Zhao, J K; Herwig, K W; Robertson, J L

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm(2) to 20 × 20 mm(2). This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  18. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

    Energy Technology Data Exchange (ETDEWEB)

    Gallmeier, F. X., E-mail: gallmeierfz@ornl.gov; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L. [Instrument and Source Division, Oak Ridge National Laboratory, P.O. Box 2008, MS6466, Oak Ridge, Tennessee 37831 (United States)

    2016-06-15

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm{sup 2} to 20 × 20 mm{sup 2}. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments’ sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  19. Thermo-structural analysis and design consideration of the replaceable backwall in IFMIF liquid lithium target

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, H. [Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195 (Japan)]. E-mail: nakamura.hiroo@jaea.go.jp; Ida, M. [Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195 (Japan); Chida, T. [Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195 (Japan); Shiba, K. [Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195 (Japan); Shimizu, K. [Mitsubishi Heavy Industry, Hyogo 652-8585 (Japan); Sugimoto, M. [Japan Atomic Energy Agency, Tokai-mura, Ibaraki 319-1195 (Japan)

    2007-08-01

    The IFMIF is an accelerator-based intense neutron source for testing candidate materials for fusion reactors. Intense neutrons are emitted inside the Li flow through a backwall. The backwall made of 316L stainless steel or RAFM is attached to the target assembly with a lip seal welded by a YAG laser. Since the backwall is operating under a severe neutron irradiation of 50 dpa/year and a maximum nuclear heating rate of 25 W/cm{sup 3}, thermo-structural design is one of critical issues in a target design. Thermal stress was calculated using the ABAQUS code. As a permissible stress, yield strength at 300 {sup o}C was used. In the case of the 316 stainless steel backwall, the maximum thermal stress was more than the permissible stress (164 MPa). On the other hand, in case of the F82H backwall, a maximum thermal stress was below the permissible stress (455 MPa). Therefore, F82H is recommended as the backwall material.

  20. R&D of A MW-class solid-target for a spallation neutron source

    Science.gov (United States)

    Kawai, Masayoshi; Furusaka, Michihiro; Kikuchi, Kenji; Kurishita, Hiroaki; Watanabe, Ryuzo; Li, Jing-Feng; Sugimoto, Katsuhisa; Yamamura, Tsutomu; Hiraoka, Yutaka; Abe, Katsunori; Hasegawa, Akira; Yoshiie, Masatoshi; Takenaka, Hiroyuki; Mishima, Katsuichiro; Kiyanagi, Yoshiaki; Tanabe, Tetsuo; Yoshida, Naoaki; Igarashi, Tadashi

    2003-05-01

    R&D for a MW-class solid target composed of tungsten was undertaken to produce a pulsed intense neutron source for a future neutron scattering-facility. In order to solve the corrosion of tungsten, tungsten target blocks were clad with tantalum by means of HIP'ing, brazing and electrolytic coating in a molten salt bath. The applicability of the HIP'ing method was tested through fabricating target blocks for KENS (spallation neutron source at KEK). A further investigation to certify the optimum HIP conditions was made with the small punch test method. The results showed that the optimum temperature was 1500 °C at which the W/Ta interface gave the strongest fracture strength. In the case of the block with a hole for thermocouple, it was found that the fabrication preciseness of a straight hole and a tantalum sheath influenced the results. The development of a tungsten stainless-steel alloy was tried to produce a bare tungsten target, using techniques in powder metallurgy. Corrosion tests for various tungsten alloys were made while varying the water temperature and velocity. The mass loss of tungsten in very slow water at 180 °C was as low as 0.022 mg/y, but increased remarkably with water velocity. Simulation experiments for radiation damage to supplement the STIP-III experiments were made to investigate material hardening by hydrogen and helium, and microstructures irradiated by electrons. Both experiments showed consistent results on the order of the dislocation numbers and irradiation hardness among the different tungsten materials. Thermal-hydraulic designs were made for two types of solid target system of tungsten: slab and rod geometry as a function of the proton beam power. The neutronic performance of a solid target system was compared with that of mercury target based on Monte Carlo calculations by using the MCNP code.

  1. Radioactive Ion Beam Production by Fast-Neutron-Induced Fission in Actinide Targets at EURISOL

    CERN Document Server

    Herrera-Martínez, Adonai

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, the production of high-intensity RIBs of specific neutron-rich isotopes is obtained by inducing fission in large-mass actinide targets. In our contribution, the use of uranium targets is shown to be advantageous to other materials, such as thorium. Therefore, in order to produce fissions in U-238 and reduce the plutonium inventory, a fast neutron energy spectrum is necessary. The large beam power required to achieve these RIB levels requires the use of a liquid proton-to-neutron converter. This article details the design parameters of the converter, with special attention to the coupled neutronics of the liquid converter and fission target. Calculations performed with the ...

  2. Determination of the parahydrogen fraction in a liquid hydrogen target using energy-dependent slow neutron transmission

    Energy Technology Data Exchange (ETDEWEB)

    Barron-Palos, L., E-mail: libertad@fisica.unam.mx [Arizona State University, Tempe, AZ 85287 (United States); Alarcon, R.; Balascuta, S. [Arizona State University, Tempe, AZ 85287 (United States); Blessinger, C. [Indiana University, Bloomington, IN 47405 (United States); Bowman, J.D. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Chupp, T.E. [University of Michigan, Ann Arbor, MI 48104 (United States); Covrig, S. [University of New Hampshire, Durham, NH 03824 (United States); Crawford, C.B. [University of Tennessee, Knoxville, TN 37996 (United States); Dabaghyan, M. [University of New Hampshire, Durham, NH 03824 (United States); Dadras, J. [University of Tennessee, Knoxville, TN 37996 (United States); Dawkins, M.; Fox, W. [Indiana University, Bloomington, IN 47405 (United States); Gericke, M.T. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Gillis, R.C. [University of Manitoba, Winnipeg, MB, Canada R3T 2N2 (Canada); Lauss, B. [University of California, Berkeley, CA 94720 (United States); Leuschner, M.B.; Lozowski, B. [Indiana University, Bloomington, IN 47405 (United States); Mahurin, R. [University of Tennessee, Knoxville, TN 37996 (United States); Mason, M. [University of New Hampshire, Durham, NH 03824 (United States); Mei, J. [Indiana University, Bloomington, IN 47405 (United States); and others

    2011-12-11

    The NPDGamma collaboration is performing a measurement of the very small parity-violating asymmetry in the angular distribution of the 2.2 MeV {gamma}-rays from the capture of polarized cold neutrons on protons (A{sub {gamma}}). The estimated size of A{sub {gamma}} is 5 Multiplication-Sign 10{sup -8}, and the measured asymmetry is proportional to the neutron polarization upon capture. Since the interaction of polarized neutrons with one of the two hydrogen molecular states (orthohydrogen) can lead to neutron spin-flip scattering, it is essential that the hydrogen in the target is mostly in the molecular state that will not depolarize the neutrons ({>=}99.8% parahydrogen). For that purpose, in the first stage of the NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE), we operated a 16-l liquid hydrogen target, which was filled in two different occasions. The parahydrogen fraction in the target was accurately determined in situ by relative neutron transmission measurements. The result of these measurements indicate that the fraction of parahydrogen in equilibrium was 0.9998{+-}0.0002 in the first data taking run and 0.9956{+-}0.0002 in the second. We describe the parahydrogen monitor system, relevant aspects of the hydrogen target, and the procedure to determine the fraction of parahydrogen in the target. Also assuming thermal equilibrium of the target, we extract the scattering cross-section for neutrons on parahydrogen.

  3. Optimization studies of photo-neutron production in high- metallic targets using high energy electron beam for ADS and transmutation

    Indian Academy of Sciences (India)

    V C Petwal; V K Senecha; K V Subbaiah; H C Soni; S Kotaiah

    2007-02-01

    Monte Carlo calculations have been performed using MCNP code to study the optimization of photo-neutron yield for different electron beam energies impinging on Pb, W and Ta cylindrical targets of varying thickness. It is noticed that photo-neutron yield can be increased for electron beam energies ≥ 100 MeV for appropriate thickness of the target. It is also noticed that it can be maximized by further increasing the thickness of the target. Further, at higher electron beam energy heat gradient in the target decreases, which facilitates easier heat removal from the target. This can help in developing a photo-neutron source based on electron LINAC by choosing appropriate electron beam energy and target thickness to optimize the neutron flux for ADS, transmutation studies and as high energy neutron source etc. Photo-neutron yield for different targets, optimum target thickness and photo-neutron energy spectrum and heat deposition by electron beam for different incident energy is presented.

  4. Study on collimation and shielding of the back-streaming neutrons at the CSNS target

    CERN Document Server

    Han-Tao, Jing; Zheng, Yang

    2013-01-01

    The back-streaming neutrons from the spallation target at CSNS are very intense, and can pose serious damage problems for the devices in the accelerator-target interface region. To tackle the problems, a possible scheme for this region was studied, namely a specially designed optics for the proton beam line produces two beam waists, and two collimators are placed at the two waist positions to maximize the collimation effect of the back-streaming neutrons. Detailed Monte Carlo simulations with the beams in the two different CSNS phases show the effectiveness of the collimation system, and the radiation dose rate decreases largely in the interface section. This can ensure the use of epoxy coils for the last magnets and other devices in the beam transport line with reasonable lifetimes, e.g. thirty years. The design philosophy for such an accelerator-target interface region can also be applicable to other high-power proton beam applications.

  5. Antiproton Radiotherapy Peripheral Dose from Secondary Neutrons produced in the Annihilation of Antiprotons in the Target

    CERN Document Server

    Fahimian, Benjamin P; Keyes, Roy; Bassler, Niels; Iwamoto, Keisuke S; Zankl, Maria; Holzscheiter, Michael H

    2009-01-01

    The AD-4/ACE collaboration studies the biological effects of antiprotons with respect to a possible use of antiprotons in cancer therapy. In vitro experiments performed by the collaboration have shown an enhanced biological effectiveness for antiprotons relative to protons. One concern is the normal tissue dose resulting from secondary neutrons produced in the annihilation of antiprotons on the nucleons of the target atoms. Here we present the first organ specific Monte Carlo calculations of normal tissue equivalent neutron dose in antiproton therapy through the use of a segmented CT-based human phantom. The MCNPX Monte Carlo code was employed to quantify the peripheral dose for a cylindrical spread out Bragg peak representing a treatment volume of 1 cm diameter and 1 cm length in the frontal lobe of a segmented whole-body phantom of a 38 year old male. The secondary neutron organ dose was tallied as a function of energy and organ.

  6. Preliminary Formulation of Finite Element Solution for the 1-D, 1-G Time Dependent Neutron Diffusion Equation without Consideration about Delay Neutron

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Eun Hyun; Song, Yong Mann; Park, Joo Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    If time-dependent equation is solved with the FEM, the limitation of the input geometry will disappear. It has often been pointed out that the numerical methods implemented in the RFSP code are not state-of-the-art. Although an acceleration method such as the Coarse Mesh Finite Difference (CMFD) for Finite Difference Method (FDM) does not exist for the FEM, one should keep in mind that the number of time steps for the transient simulation is not large. The rigorous formulation in this study will richen the theoretical basis of the FEM and lead to an extension of the dynamics code to deal with a more complicated problem. In this study, the formulation for the 1-D, 1-G Time Dependent Neutron Diffusion Equation (TDNDE) without consideration of the delay neutron will first be done. A problem including one multiplying medium will be solved. Also several conclusions from a comparison between the numerical and analytic solutions, a comparison between solutions with various element orders, and a comparison between solutions with different time differencing will be made to be certain about the formulation and FEM solution. By investigating various cases with different values of albedo, theta, and the order of elements, it can be concluded that the finite element solution is agree well with the analytic solution. The higher the element order used, the higher the accuracy improvements are obtained.

  7. Considerations for boron neutron capture therapy studies; Consideracoes sobre o estudo da BNCT (terapia de captura neutronica por boro)

    Energy Technology Data Exchange (ETDEWEB)

    Faria Gaspar, P. de

    1994-12-31

    Radiotherapy is indispensable as a mean to eradicate deeply or infiltrating tumor tissue that can not be removed surgically. Therefore, it is not selective and may also kill the surrounding health tissue. The principle of BNCT (Boron Neutron Capture Therapy) consist in targeting a tumor selectively with a boron-10 compound. This nuclide has a large capture cross section for thermal neutrons and the nuclear reaction and the delivered energy in locus will selective the tumor. Since its initial proposal in 1963 BNCT has made much progress, however it is not used in a routine treatment. In this work it was approached some complex procedures, as the obtention of selective boron compounds, the adequate set up of neutron beams, the biodistribution, the in vivo and in vitro studies, and also human patients treatments. This work provide fundamentals about BNCT to professional of different areas of knowledge since it comprises multidisciplinary study. It includes appendixes for the ones not related to the field for a better comprehension of the many aspects involved. It is also presented a glossary containing technical and basic aspects involved. It is also presented a glossary containing technical and basic terms referred in the work. (author). 174 refs, 1 fig, 12 apps.

  8. Heat transfer and core neutronics considerations of the heat pipe cooled thermionic reactor

    Science.gov (United States)

    Determan, W. R.; Lewis, Brian

    1991-01-01

    The authors summarize the results of detailed neutronic and thermal-hydraulic evaluations of the heat pipe cooled thermionic (HPTI) reactor design, identify its key design attributes, and quantify its performance characteristics. The HPTI core uses modular, liquid-metal core heat transfer assemblies to replace the liquid-metal heat transport loop employed by in-core thermionic reactor designs of the past. The nuclear fuel, power conversion, heat transport, and heat rejection functions are all combined into a single modular unit. The reactor/converter assembly uses UN fuel pins to obtain a critical core configuration with in-core safety rods and reflector controls added to complete the subassembly. By thermally bonding the core heat transfer assemblies during the reactor core is coupled neutronically, thermally, and electrically into a modular assembly of individual power sources with cross-tied architecture. A forward-facing heat pipe radiator assembly extends from the reactor head in the shape of a frustum of a cone on the opposite side of the power system from the payload. Important virtues of the concept are the absence of any single-point failures and the ability of the core to effectively transfer the TFE waste heat load laterally to other in-core heat transfer assemblies in the event of multiple failures in either in-core and radiator heat pipes.

  9. Heat transfer and core neutronics considerations of the heat pipe cooled thermionic reactor

    Science.gov (United States)

    Determan, W. R.; Lewis, Brian

    The authors summarize the results of detailed neutronic and thermal-hydraulic evaluations of the heat pipe cooled thermionic (HPTI) reactor design, identify its key design attributes, and quantify its performance characteristics. The HPTI core uses modular, liquid-metal core heat transfer assemblies to replace the liquid-metal heat transport loop employed by in-core thermionic reactor designs of the past. The nuclear fuel, power conversion, heat transport, and heat rejection functions are all combined into a single modular unit. The reactor/converter assembly uses UN fuel pins to obtain a critical core configuration with in-core safety rods and reflector controls added to complete the subassembly. By thermally bonding the core heat transfer assemblies during the reactor core is coupled neutronically, thermally, and electrically into a modular assembly of individual power sources with cross-tied architecture. A forward-facing heat pipe radiator assembly extends from the reactor head in the shape of a frustum of a cone on the opposite side of the power system from the payload. Important virtues of the concept are the absence of any single-point failures and the ability of the core to effectively transfer the TFE waste heat load laterally to other in-core heat transfer assemblies in the event of multiple failures in either in-core and radiator heat pipes.

  10. Total cross sections for neutron scattering from few nucleon systems. II. Theoretical considerations.^.

    Science.gov (United States)

    Elster, Ch.; Abfalterer, W. P.; Bateman, F. B.; Dietrich, F. S.; Finlay, R. W.; Glöckle, W.; Golak, J.; Haight, R. C.; Hüber, D.; Morgan, G. L.; Witala, H.

    1998-04-01

    New high precision measurements of the difference in neutron total cross sections of deuterium and hydrogen (d-h) were performed for neutron energies between 10 and 600 MeV. The results are compared to state-of-the-art Faddeev calculations of the n+d total cross section between 10 and 300 MeV, which systematically underpredict the experiment above 100 MeV. This result is not very sensitive to the type of modern NN interaction employed. Further, the convergence of the Faddeev multiple scattering series is demonstrated. We therefore conclude that the Faddeev description is inadequate above 100 MeV projectile energy. We also consider the first and second order terms in the multiple scattering series in the high energy limit to study shadowing effects. [1mm] ^ This work is supported in part by the U.S. Department of Energy under Contracts W-7405-ENG-48 (LLNL), W-7405-ENG-36 (LANL), and DE-FG02-93ER40756 (Ohio U.), the Deutsche Forschungsgemeinschaft (DFG), the Ohio Supercomputer Center (OSC) and the HLRZ Jülich.

  11. Neutron distribution and yield produced by 50 MeV/u 18O-ion on thick targets

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Neutron energy, fluence rate, angular distributions anddose equivalent rate distributions around the thick Be, Cu,Au targets bombarded by 50 MeV/u 18O-ion were measured usinga threshold detector activation method. At the same time, theneutron yields of 18O-ion and the neutron emission rates inthe forward direction were obtained approximately.

  12. Comparison of Different INC Physical Models of MCNPX to Compute Spallation Neutronics of LBE Target

    Science.gov (United States)

    Feghhi, Seyed Amir Hossein; Gholamzadeh, Zohreh; Tenreiro, Claudio; Alipoor, Zahra

    2015-04-01

    Spallation particles can utilize in different fields such as neutron scattering studies, external source for burning spent fuel as well as running subcritical reactors. Different computational particle transport codes are widely used to model spallation process into the heavy targets. Among these codes, MCNPX 2.6.0 comprises various intra nuclear cascade models for spallation calculations. Impact of different intra nuclear cascade models on calculation of neutronic parameters of LBE target has been evaluated in this work. Escaped neutron yield, energy deposition and residual nuclei production in the spallation target has been calculated using the physical models. A comparison between the computational and experimental has been carried out to validate the computational data. The simulation data showed there is a good conformity between the obtained data from Bertini/Drenser and Isabel/Drenser. The data achieved by Bertini/Abla and Isabel/Abla models are close to each other for the studied parameters as well. Among the studied models, CEM showed more discrepancies with experimental and other computational data. According to the obtained data, INCL4/Drenser, INCL4/Abla and Isabel/Drenser models can meet more agreements with experimental data.

  13. Scaling Up Renewable Energy Generation: Aligning Targets and Incentives with Grid Integration Considerations, Greening The Grid

    Energy Technology Data Exchange (ETDEWEB)

    Katz, Jessica; Cochran, Jaquelin

    2015-05-27

    Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. This document, part of a Greening the Grid toolkit, provides power system planners with tips to help secure and sustain investment in new renewable energy generation by aligning renewable energy policy targets and incentives with grid integration considerations.

  14. Study on target spallation reaction cross sections induced by high energy neutrons and heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takashi [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center

    1996-03-01

    The target spallation reaction cross sections of neutrons and heavy ions which have not been observed are determined in this paper. The object of this work is to make clear the differences between the spallation reaction cross section of neutron and that of proton by comparing the obtained value of neutron with the known value of proton. To this end, the quasi monochromatic neutron field of 20{approx}50 MeV was developed in 4 cyclotrons, INS, CYRIC, TIARA and RIKEN. The nuclear spallation reaction cross sections of C, Al and Bi were measured in the above field and the distribution of nuclear spallation reaction products in Cu determined by C ion beam of HIMAC. {sup 12}C(n,2n){sup 11}C reaction cross section shows the maximum value of about 20 mb at near 40{approx}50 MeV and then the value gradually decreased to 10 mb. The cross sections of {sup 209}Bi(n,Xn) are shown. The distribution of {sup 61}Cu is lower at the entrance and higher in the depth. (S.Y.)

  15. Boron containing magnetic nanoparticles for neutron capture therapy--an innovative approach for specifically targeting tumors.

    Science.gov (United States)

    Tietze, Rainer; Unterweger, Harald; Dürr, Stephan; Lyer, Stefan; Canella, Lea; Kudejova, Petra; Wagner, Franz M; Petry, Winfried; Taccardi, Nicola; Alexiou, Christoph

    2015-12-01

    The selective delivery of (10)B into the tumor tissue remains to be further improved for successful and reliable Boron Neutron Capture Therapy applications. Magnetic Drug Targeting using intraarterially administered superparamagnetic nanoparticles and external magnetic fields already exhibited convincing results in terms of highly efficient and selective drug deposition. Using the same technique for the targeted (10)B delivery is a promising new approach. Here, systematic irradiation experiments of phantom cubes containing different concentrations of boron and nanoparticles as well as varying three-dimensional arrangements have been performed.

  16. 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

    Science.gov (United States)

    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.

  17. Influence of Different Moderator Materials on Characteristics of Neutron Fluxes Generated under Irradiation of Lead Target with Proton Beams

    CERN Document Server

    Sosnin, A N; Polanski, A; Petrochenkov, S A; Golovatyuk, V M; Krivopustov, M I; Bamblevski, V P; Westmeier, W; Odoj, R; Brandt, R; Robotham, H; Hashemi-Nezhad, S R; Zamani-Valassiadou, M

    2002-01-01

    Neutron fields generated in extended heavy (Z\\geq 82) targets under irradiation with proton beams at energies in the range of 1 GeV are investigated. Influence of different moderators on the spectra and multiplicities of neutrons escaping the surface of the assembly consisting of a lead target (\\varnothing 8 cm\\times 20 cm or \\varnothing 8cm\\times 50 cm) screened by variable thickness of polyethylene or graphite, respectively, was compared in the present work. It is shown that the effectiveness of graphite as a material used in such assemblies to moderate spallation neutrons down to thermal energies is significantly lower than that of paraffin.

  18. Geant4 simulations of the neutron production and transport in the n_TOF spallation target

    Science.gov (United States)

    Lerendegui-Marco, J.; Cortés-Giraldo, M. A.; Guerrero, C.; Quesada, J. M.

    2016-11-01

    The neutron production and transport in the spallation target of the n_TOF facility at CERN has been simulated with Geant4. The results obtained with the different hadronic Physics Lists provided by Geant4 have been compared with the experimental neutron flux in n_TOF-EAR1. The best overall agreement in both the absolute value and the energy dependence of the flux from thermal to 1GeV, is obtained with the INCL++ model coupled with the Fritiof Model(FTFP). This Physics List has been thus used to simulate and study the main features of the new n_TOF-EAR2 beam line, currently in its commissioning phase.

  19. One-neutron stripping reactions of 11Be and 19C on light target

    Indian Academy of Sciences (India)

    Rajesh Kharab; Ravinder Kumar; Pradeep Singh; H C Sharma

    2007-05-01

    We have calculated the one-neutron absorption cross-section and the longitudinal momentum distribution of the core fragment coming out from the breakup of 11Be and 19C on 9Be target at 63 MeV/A and 88 MeV/A beam energies respectively. The reaction mechanism is treated within the framework of the eikonal approximation. The effective range of the nuclear interaction between the core and the valence neutron within the projectile has been determined by comparing the predicted stripping crosssection with the recently measured one. The effective range for 19C has been found to besmaller than that for 11Be. It qualitatively indicates that 19C is slightly more halo than 11Be. The smaller width, predicted as well as measured, of the LMD of 18C than 10Be also strengthens this fact. The experimental data concerning the LMD of core fragments have been well represented.

  20. Neutron yield of thick 12C and 13C targets with 20 and 30 MeV deuterons

    Science.gov (United States)

    Lhersonneau, G.; Malkiewicz, T.; Fadil, M.; Gorelov, D.; Jones, P.; Ngcobo, P. Z.; Sorri, J.; Trzaska, W. H.

    2016-12-01

    The neutron yield of thick targets of carbon, natural and enriched in 13C, bombarded by deuterons of 20 and 30 MeV has been measured by the activation method. The gain with respect to a 12C target is the same as with protons beams. The yield ratio is about 1.2 only and hardly can justify the use of a 13C target with deuteron beams. The data, apart from being of interest for the design of facilities where secondary neutron beams are used, provide a test case for calculations where both beam and target have a weakly bound neutron. The MCNPx code version 2.6.0, despite failing to reproduce some details of the experimental distributions, describes their global properties fairly well, especially the relative yields of the 12C and 13C targets.

  1. ACCELERATOR SYSTEMS MODIFICATIONS FOR A SECOND TARGET STATION AT THE OAK RIDGE SPALLATION NEUTRON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Galambos, John D [ORNL; Kim, Sang-Ho [ORNL; Plum, Michael A [ORNL

    2014-01-01

    A second target station is planned for the Oak Ridge Spallation Neutron Source. The ion source will be upgraded to increase the peak current from 38 to 49 mA, additional superconducting RF cavities will be added to the linac to increase the H beam energy from 938 to 1300 MeV, and the accumulator ring will receive modifications to the injection and extraction systems to accommodate the higher beam energy. After pulse compression in the storage ring one sixth of the beam pulses (10 out of 60 Hz) will be diverted to the second target by kicker and septum magnets added to the existing Ring to Target Beam Transport (RTBT) line. No further modifications will be made to the RTBT so that when the kicker and septum magnets are turned off the original beam transport lattice will be unaffected. In this paper we will discuss these and other planned modifications and upgrades to the accelerator facility.

  2. Thermal-hydraulic simulation of mercury target concepts for a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Siman-Tov, M.; Wendel, M.; Haines, J. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    The Oak Ridge Spallation Neutron Source (ORSNS) is a high-power, accelerator-based pulsed spallation neutron source being designed by a multi-laboratory team led by Oak Ridge National Laboratory to achieve very high fluxes of neutrons for scientific experiments. The ORSNS is projected to have a 1 MW proton beam upgradable to 5 MW. About 60% of the beam power (1-5 MW, 17-83 kJ/pulse in 0.5 microsec at 60 cps) is deposited in the liquid metal (mercury) target having the dimensions of 65x30x10 cm (about 19.5 liter). Peak steady state power density is about 150 and 785 MW/m{sup 3} for 1 MW and 5 MW beam respectively, whereas peak pulsed power density is as high as 5.2 and 26.1 GW/m{sup 3}, respectively. The peak pulse temperature rise rate is 14 million C/s (for 5 MW beam) whereas the total pulse temperature rise is only 7 C. In addition to thermal shock and materials compatibility, key feasibility issues for the target are related to its thermal-hydraulic performance. This includes proper flow distribution, flow reversals, possible {open_quotes}hot spots{close_quotes} and the challenge of mitigating the effects of thermal shock through possible injection of helium bubbles throughout the mercury volume or other concepts. The general computational fluid dynamics (CFD) code CFDS-FLOW3D was used to simulate the thermal and flow distribution in three preliminary concepts of the mercury target. Very initial CFD simulation of He bubbles injection demonstrates some potential for simulating behavior of He bubbles in flowing mercury. Much study and development will be required to be able to `predict`, even in a crude way, such a complex phenomena. Future direction in both design and R&D is outlined.

  3. EURISOL Multi-MW Target Station - MAFF Configuration - Neutron Fluxes, Fission Rates, Dose Rates and Activation

    CERN Document Server

    Luis, R; Goncalves, I. F; Vaz, P; Kadi, Y; Kharoua, C; Rocca, R; Bermudez, J; Tecchio, L; Negoita, F; Ene, D; David, J.C

    The EURISOL (The EURopean Isotope Separation On-Line Radioactive Ion Beam) project aims atproducing high intensity radioactive ion beams produced by neutron-induced fission on fissile targets(235U) surrounding a liquid mercury converter. A proton beam of 1GeV and 4MW impinges on theconverter, generating, by spallation reactions, high neutron fluxes that induce fission in thesurrounding fissile targets.In this work the state-of-the-art Monte Carlo codes MCNPX and FLUKA were used to assess theneutronics performance of the system, which geometry, inspired in the MAFF concept, allows aversatile manipulation of the fission targets. The first objective of the study was to optimize thegeometry and the materials used in the fuel and reflector elements of the system, in order to achievethe highest possible fission rates. Indeed, it is shown that the appropriate combination of fission targetmaterial and surrounding reflector material leads to the aimed value of 1015 fissions/s per fissiontarget. The second part of this...

  4. Effect of Target Configuration on the Neutronic Performance of the Gas-Cooled ADS

    CERN Document Server

    Biss, K; Shetty, N; Nabbi, R

    2013-01-01

    With the utilization of nuclear energy transuranic elements like Pu, Am and Cm are produced causing high, long term radioactivity and radio toxicity, respectively. To reduce the radiological impact on the environment and to the repository Partitioning and Transmutation is considered as an efficient way. In this respect comprehensive research works are performed at different research institutes worldwide. The results show that the transmutation of TRU is achieved with fast neutrons due to the higher fission probability. Based on Accelerator Driven Systems (ADS) those neutrons are used in a particular system, in which mainly liquid metal eutectic (lead bismuth) is used as coolant. The neutronic performance of an ADS system based on gas cooling was studied in this work by using the simulation tool MCNPX. The usage of the Monte-Carlo method in MCNPX allows the simulation of the physical processes in a 3D-model of the core. In dependence of the spallation target material and design several parameters like the mult...

  5. Lithium antineutrino source in the tandem scheme of the accelerator and neutron producting tungsten target

    CERN Document Server

    Lyashuk, V I

    2016-01-01

    The antineutrinos of the neutron rich 8Li isotope is characterized by hard and good defined spectrum - averaged energy is 6.5 MeV and maximal - up to 13 MeV. An intensive antineutrino source with such parameters can be unique instrument for neutrino investigations and especially for search of sterile neutrinos. The 8Li can be produced by (n,gamma)-activation of 7Li isotope. The proposed scheme of the antineutrino source is based on the lithium blanket around the accelerator neutron producting target. We propose to use heavy water solution of the lithium hydroxide instead of lithium in metallic state. Such solution for lithium blanket substance ensure the large perspectives in real steps for creation of this installation. An analyses of neutron fields in the blanket and distribution of 8Li creation allows to propose the next principal steps in the construction of the lithium blanket. We propose to enclose the blanket volume isolating it's central part with more high 8Li production. This solution allows to decr...

  6. Monitoring method of neutron flux for the spallation target used in an accelerator driven sub-critical systems

    CERN Document Server

    Zhao, Qiang; Yang, Lei; Zhang, Xueying; Cui, Wenjuan; Chen, Zhiqiang; Xu, Hushan

    2015-01-01

    In this paper, we study the monitoring method of neutron flux for the spallation target used in an accelerator driven sub-critical (ADS) system, where the spallation target located vertically at the centre of a sub-critical core is bombarded vertically by the high-energy protons from an accelerator. First, by considering the characteristics in the spatial variation of neutron flux from the spallation target, we propose the following multi-point measurement technique, i.e. the spallation neutron flux should be measured at multiple vertical locations. To explain why the flux should be measured at multiple locations, we have studied the neutron production from tungsten target bombarded by a 250 MeV-proton beam with the Geant4-based Monte Carlo simulations. The simulation results have indicated that the neutron flux at the central location is up to three orders of magnitude higher than the flux at the lower locations. Secondly, we have developed an effective technique in order to measure the spallation neutron fl...

  7. Production of neutron-rich isotopes by one- and two-step processes in ISOL targets

    CERN Document Server

    Portillo, M; Gomes, I; Panteleev, V N; Fedorov, D V; Barzakh, A E; Beznosjuk, V I; Moroz, F V; Orlov, S Y; Volkov, Y M

    2002-01-01

    The results are presented for an experiment that compares the difference between a one- and two-step reaction setup using 1 GeV protons. The rates of production from an on-line isotope separator target containing UCx are measured for isotopes in the neutron mass region of Rb and Cs. Some details about the measured results and predictions by the Monte Carlo models are discussed. The effects of the delayed release on the extracted efficiency are generalized using analytical models for application to a wide range of nuclear decay lifetimes.

  8. A fission-fragment-sensitive target for X-ray spectroscopy in neutron-induced fission

    CERN Document Server

    Ethvignot, T; Giot, L; Casoli, P; Nelson, R O

    2002-01-01

    A fission-fragment-sensitive detector built for low-energy photon spectroscopy applications at the WNR 'white' neutron source at Los Alamos is described. The detector consists of eight layers of thin photovoltaic cells, onto which 1 mg/cm sup 2 of pure sup 2 sup 3 sup 8 U is deposited. The detector serves as an active target to select fission events from background and other reaction channels. The fairly small thickness of the detector with respect to transmission of 20-50 keV photons permits the measurement of prompt fission-fragment X-rays. Results with the GEANIE photon spectrometer are presented.

  9. ANEM: A rotating composite target to produce an atmospheric-like neutron beam at the LNL SPES facility

    Science.gov (United States)

    Acosta Urdaneta, Gabriela Carolina; Bisello, Dario; Esposito, Juan; Mastinu, Pierfrancesco; Prete, Gianfranco; Silvestrin, Luca; Wyss, Jeffery

    2016-09-01

    A fast neutron (E> MeV) irradiation facility is under development at the 70 MeV SPES proton cyclotron at LNL (Legnaro, Italy) to investigate neutron-induced Single Event Effects (SEE) in microelectronic devices and systems. After an overview on neutron-induced SEE in electronics, we report on the progress in the design of ANEM (Atmospheric Neutron EMulator), a water-cooled rotating target made of Be and W to produce neutrons with an energy spectrum similar to that of neutrons produced by cosmic rays at sea-level. In ANEM, the protons from the cyclotron alternatively impinge on two circular sectors of Be and W of different areas; the effective neutron spectrum is a weighted combination of the spectra from the two sectors. In this contribution, we present the results of thermal-mechanical Finite Element Analysis (ANSYS) calculations of the performance of the ANEM prototype. The calculations at this stage indicate that ANEM can deliver fast neutrons with an atmospheric-like energy spectrum and with an integral flux Φn(1-70 MeV) ˜107 n cm-2s-1 that is 3×109 more intense than the natural one at sea-level: a very competitive flux for SEE testing.

  10. Spallation Neutron Spectrum on a Massive Lead/Paraffin Target Irradiated with 1 GeV Protons

    CERN Document Server

    Adam, J; Barashenkov, V S; Brandt, R; Golovatiouk, V M; Kalinnikov, V G; Katovsky, K; Krivopustov, M I; Kumar, V; Kumawat, H; Odoj, R; Pronskikh, V S; Solnyshkin, A A; Stegailov, V I; Tsoupko-Sitnikov, V M; Westmeier, W

    2004-01-01

    The spectra of gamma-ray emitted by decaying residual nuclei, produced by spallation neutrons with (n, xn), (n,xnyp), (n,p), (n,gamma) reactions in activation threshold detectors - namely, ^{209}Bi, ^{197}Au, ^{59}Co, ^{115}In, ^{232}Th, were measured in the Laboratory of Nuclear Problems (LNP), JINR, Dubna, Russia. Spallation neutrons were generated by bombarding a 20 cm long cylindrical lead target, 8 cm in diameter, surrounded by a 6 cm thick layer of paraffin moderator, with a 1 GeV proton beam from the Nuclotron accelerator. Reaction rates and spallation neutron spectrum were measured and compared with CASCADE code calculations.

  11. Spectroscopy of neutron rich nuclei using cold neutron induced fission of actinide targets at the ILL: the EXILL campaign

    Directory of Open Access Journals (Sweden)

    de France G.

    2014-03-01

    Full Text Available A combination of germanium detectors has been installed at the PF1B neutron guide of the ILL to perform the prompt spectroscopy of neutron-rich nuclei produced in the neutron-capture induced-fission of 235U and 241Pu. In addition LaBr3 detectors from the FATIMA collaboration have been installed in complement with the EXOGAM clovers to measure lifetimes of low-lying excited states. The measured characteristics and online spectra indicate very good performances of the overall setup.

  12. Development of high pressure deuterium gas targets for the generation of intense mono-energetic fast neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Guzek, J. E-mail: jguzek@debeers.co.za; Richardson, K.; Franklyn, C.B.; Waites, A.; McMurray, W.R.; Watterson, J.I.W.; Tapper, U.A.S

    1999-06-01

    Two different technical solutions to the problem of generation of mono-energetic fast neutron beams on the gaseous targets are presented here. A simple and cost-effective design of a cooled windowed gas target system is described in the first part of this paper. It utilises a thin metallic foil window and circulating deuterium gas cooled down to 100 K. The ultimate beam handling capability of such target is determined by the properties of the window. Reliable performance of this gas target system was achieved at 1 bar of deuterium gas, when exposed to a 45 {mu}A beam of 5 MeV deuterons, for periods in excess of 6 h. Cooling of the target gas resulted in increased fast neutron output and improved neutron to gamma-ray ratio. The second part of this paper discusses the design of a high pressure, windowless gas target for use with pulsed, low duty cycle accelerators. A rotating seal concept was applied to reduce the gas load in a differentially pumped system. This allows operation at 1.23 bar of deuterium gas pressure in the gas cell region. Such a gas target system is free from the limitations of the windowed target but special attention has to be paid to the heat dissipation capability of the beam dump, due to the use of a thin target. The rotating seal concept is particularly suitable for use with accelerators such as radio-frequency quadrupole (RFQ) linacs that operate with a very high peak current at low duty cycle. The performance of both target systems was comprehensively characterized using the time-of-flight (TOF) technique. This demonstrated that very good quality mono-energetic fast neutron beams were produced with the slow neutron and gamma-ray component below 10% of the total target output.

  13. Demonstration of a high-intensity neutron source based on a liquid-lithium target for Accelerator based Boron Neutron Capture Therapy.

    Science.gov (United States)

    Halfon, S; Arenshtam, A; Kijel, D; Paul, M; Weissman, L; Berkovits, D; Eliyahu, I; Feinberg, G; Kreisel, A; Mardor, I; Shimel, G; Shor, A; Silverman, I; Tessler, M

    2015-12-01

    A free surface liquid-lithium jet target is operating routinely at Soreq Applied Research Accelerator Facility (SARAF), bombarded with a ~1.91 MeV, ~1.2 mA continuous-wave narrow proton beam. The experiments demonstrate the liquid lithium target (LiLiT) capability to constitute an intense source of epithermal neutrons, for Accelerator based Boron Neutron Capture Therapy (BNCT). The target dissipates extremely high ion beam power densities (>3 kW/cm(2), >0.5 MW/cm(3)) for long periods of time, while maintaining stable conditions and localized residual activity. LiLiT generates ~3×10(10) n/s, which is more than one order of magnitude larger than conventional (7)Li(p,n)-based near threshold neutron sources. A shield and moderator assembly for BNCT, with LiLiT irradiated with protons at 1.91 MeV, was designed based on Monte Carlo (MCNP) simulations of BNCT-doses produced in a phantom. According to these simulations it was found that a ~15 mA near threshold proton current will apply the therapeutic doses in ~1h treatment duration. According to our present results, such high current beams can be dissipated in a liquid-lithium target, hence the target design is readily applicable for accelerator-based BNCT.

  14. 90° Neutron emission from high energy protons and lead ions on a thin lead target

    Science.gov (United States)

    Agosteo, S.; Birattari, C.; Foglio Para, A.; Mitaroff, A.; Silari, M.; Ulrici, L.

    2002-01-01

    The neutron emission from a relatively thin lead target bombarded by beams of high energy protons/pions and lead ions was measured at CERN in one of the secondary beam lines of the Super Proton Synchrotron for radiation protection and shielding calculations. Measurements were performed with three different beams: 208Pb 82+ lead ions at 40 GeV/ c per nucleon and 158 GeV/ c per nucleon, and 40 GeV/ c mixed protons/pions. The neutron yield and spectral fluence per incident ion on target were measured at 90° with respect to beam direction. Monte-Carlo simulations with the FLUKA code were performed for the case of protons and pions and the results found in good agreement with the experimental data. A comparison between simulations and experiment for protons, pions and lead ions have shown that—for such high energy heavy ion beams—a reasonable estimate can be carried out by scaling the result of a Monte-Carlo calculation for protons by the projectile mass number to the power of 0.80-0.84.

  15. A TPD and AR based comparison of accelerator neutron irradiation fields between (7)Li and W targets for BNCT.

    Science.gov (United States)

    Tanaka, Kenichi; Endo, Satoru; Yonai, Shunsuke; Baba, Mamoru; Hoshi, Masaharu

    2014-06-01

    The characteristics of moderator assembly dimension was investigated for the usage of (7)Li(p,n) neutrons by 2.3-2.8MeV protons and W(p,n) neutrons by 50MeV protons. The indexes were the treatable protocol depth (TPD) and advantage depth (AD). Consequently, a configuration for W target with the Fe filter, Fluental moderator, Pb reflector showed the TPD of 5.8cm and AD of 9.3cm. Comparable indexes were found for the Li target in a geometry with the MgF2 moderator and Teflon reflector.

  16. Neutron capture therapies

    Energy Technology Data Exchange (ETDEWEB)

    Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

    1999-01-01

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

  17. Neutron capture therapies

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-11-02

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

  18. Simulation of the Production of Secondary Particles from a Neutron Beam on Polyethylene Targets using the GEANT4 Simulation Tool

    CERN Document Server

    Ilgner, C

    2003-01-01

    In view of a beam test of RadFET semiconductor detectors and optically stimulated luminescence (OSL) detectors as on-line dosimeters for radiation monitoring purposes in the caverns of the Large Hadron Collider (LHC) experiments, a simulation on the production of secondary particles from a neutron beam on a polyethylene target was carried out. We describe the yield of recoil protons, scattered neutrons as well as electrons, positrons and photons, when neutrons of an average energy of 20 MeV hit polyethylene targets of several thicknesses. The simulation was carried out using the latest release 5.2 of the GEANT4 detector description and simulation tool, including advanced hadron interaction models.

  19. EURISOL-DS Multi-MWatt Hg Target: Neutron flux and fission rate calculations for the MAFF configuration

    CERN Document Server

    Romanets, Y; Vaz, P; Herrera-Martinez, A; Kadi, Y; Kharoua, C; Lettry, J; Lindroos, M

    The EURISOL (The EURopean Isotope Separation On-Line Radioactive Ion Beam) project aims at producing high intensity radioactive ion beams produced by neutron induced fission on a fissile target (235U) surrounding a liquid mercury converter. A proton beam of 1 GeV and 4 MW impinges on the Hg converter generating by spallation reactions high neutron fluxes. In this work the state-of-the-art Monte Carlo codes MCNPX and FLUKA were used to assess the neutronics performance of the system which geometry, inspired from the MAFF concept, allows a versatile manipulation of the fission targets. The objective of the study was to optimize the geometry of the system and the materials used in the fuel and reflector elements of the system, in order to achieve the highest possible fission rate.

  20. Neutronic and thermal-hydraulic analysis of fission molybdenum-99 production at Tehran Research Reactor using LEU plate targets.

    Science.gov (United States)

    Abedi, Ebrahim; Ebrahimkhani, Marzieh; Davari, Amin; Mirvakili, Seyed Mohammad; Tabasi, Mohsen; Maragheh, Mohammad Ghannadi

    2016-12-01

    Efficient and safe production of molybdenum-99 ((99)Mo) radiopharmaceutical at Tehran Research Reactor (TRR) via fission of LEU targets is studied. Neutronic calculations are performed to evaluate produced (99)Mo activity, core neutronic safety parameters and also the power deposition values in target plates during a 7 days irradiation interval. Thermal-hydraulic analysis has been also carried out to obtain thermal behavior of these plates. Using Thermal-hydraulic analysis, it can be concluded that the safety parameters are satisfied in the current study. Consequently, the present neutronic and thermal-hydraulic calculations show efficient (99)Mo production is accessible at significant activity values in TRR current core configuration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. A Precision Measurement of the Neutron Spin Structure Functions Using a Polarized HE-3 Target

    Energy Technology Data Exchange (ETDEWEB)

    Smith, T

    2003-11-05

    This thesis describes a precision measurement of the neutron spin dependent structure function, g{sub 1}{sup n}(x). The measurement was made by the E154 collaboration at SLAC using a longitudinally polarized, 48.3 GeV electron beam, and a {sup 3}He target polarized by spin exchange with optically pumped rubidium. A target polarization as high as 50% was achieved. The elements of the experiment which pertain to the polarized {sup 3}He target will be described in detail in this thesis. To achieve a precision measurement, it has been necessary to minimize the systematic error from the uncertainty in the target parameters. All of the parameters of the target have been carefully measured, and the most important parameters of the target have been measured using multiple techniques. The polarization of the target was measured using nuclear magnetic resonance techniques, and has been calibrated using both proton NMR and by measuring the shift of the Rb Zeeman resonance frequency due to the {sup 3}He polarization. The fraction of events which originated in the {sup 3}He, as measured by the spectrometers, has been determined using a physical model of the target and the spectrometers. It was also measured during the experiment using a variable pressure {sup 3}He reference cell in place of the polarized {sup 3}He target. The spin dependent structure function g{sub 1}{sup n}(z) was measured in the Bjorken x range of 0.014 < x < 0.7 with an average Q{sup 2} of 5 (GeV/c){sup 2}. One of the primary motivations for this experiment was to test the Bjorken sum rule. Because the experiment had smaller statistical errors and a broader kinematic coverage than previous experiments, the behavior of the spin structure function g{sub 1}{sup n}(x) could be studied in detail at low values of the Bjorken scaling variable x. It was found that g{sub 1}{sup n}(x) has a strongly divergent behavior at low values of x, calling into question the methods commonly used to extrapolate the value of g

  2. A compact fast-neutron producing target for high resolution cross section measurements

    NARCIS (Netherlands)

    Flaska, M.

    2006-01-01

    A proper knowledge of neutron cross sections is very important for the operation safety of various nuclear facilities. Reducing uncertainties in the neutron cross sections can lead to an enhanced safety of present and future nuclear power systems. Accurate neutron cross sections also play a relevant

  3. Study of neutron spectra in a water bath from a Pb target irradiated by 250 MeV protons

    Science.gov (United States)

    Li, Yan-Yan; Zhang, Xue-Ying; Ju, Yong-Qin; Ma, Fei; Zhang, Hong-Bin; Chen, Liang; Ge, Hong-Lin; Wan, Bo; Luo, Peng; Zhou, Bin; Zhang, Yan-Bin; Li, Jian-Yang; Xu, Jun-Kui; Wang, Song-Lin; Yang, Yong-Wei; Yang, Lei

    2015-04-01

    Spallation neutrons were produced by the irradiation of Pb with 250 MeV protons. The Pb target was surrounded by water which was used to slow down the emitted neutrons. The moderated neutrons in the water bath were measured by using the resonance detectors of Au, Mn and In with a cadmium (Cd) cover. According to the measured activities of the foils, the neutron flux at different resonance energies were deduced and the epithermal neutron spectra were proposed. Corresponding results calculated with the Monte Carlo code MCNPX were compared with the experimental data to check the validity of the code. The comparison showed that the simulation could give a good prediction for the neutron spectra above 50 eV, while the finite thickness of the foils greatly effected the experimental data in low energy. It was also found that the resonance detectors themselves had great impact on the simulated energy spectra. Supported by National Natural Science Foundation and Strategic Priority Research Program of the Chinese Academy of Sciences (11305229, 11105186, 91226107, 91026009, XDA03030300)

  4. Current advances in the treatment of Alzheimer's disease: focused on considerations targeting Aβ and tau

    Directory of Open Access Journals (Sweden)

    Hong-Qi Yang

    2012-10-01

    Full Text Available Abstract Alzheimer’s disease (AD is a neurodegenerative disorder that impairs mainly the memory and cognitive function in elderly. Extracellular beta amyloid deposition and intracellular tau hyperphosphorylation are the two pathological events that are thought to cause neuronal dysfunction in AD. Since the detailed mechanisms that underlie the pathogenesis of AD are still not clear, the current treatments are those drugs that can alleviate the symptoms of AD patients. Recent studies have indicated that these symptom-reliving drugs also have the ability of regulating amyloid precursor protein processing and tau phosphorylation. Thus the pharmacological mechanism of these drugs may be too simply-evaluated. This review summarizes the current status of AD therapy and some potential preclinical considerations that target beta amyloid and tau protein are also discussed.

  5. Study of Neutrons in Thick Pb Target Bombarded by 0.65~1.5 GeV Protons

    Institute of Scientific and Technical Information of China (English)

    R.Brandt; P.Vater; W.Westmeier; B.A.Kulakov; M.I.Krivopustov; A.N.Sosnin

    2001-01-01

    Study of neutrons has been carried out at thick Pb target bombarded with 0.65, 1.0 and 1.5 GeV protons from the accelerator NUCLOTRON newly built in the Joint Institute for Nuclear Research (JINR), Dubna, Russia. The Pb target is 20 cm in thickness and 8 cm in diameter. Outside the Pb target, paraffin of 6 cm in thickness is used as moderator. Proton beam from the accelerator impinged on the cylindric Pb target along its axis. The above arrangement is to simulate the core structure and nuclear reaction process of an accelerator-driven subcritical nuclear reactor. CR-39 nuclear track detector strips

  6. Ukraine experimental neutron source facility.

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Y.; Bolshinsky, I.; Nekludov, I.; Karnaukhov, I. (Nuclear Engineering Division); (INL); (Kharkov Institute of Physics and Technology)

    2008-01-01

    Kharkov Institute of Physics and Technology (KIPT) of Ukraine has a plan to construct an experimental neutron source facility. The facility has been developed for producing medical isotopes, training young nuclear professionals, supporting the Ukraine nuclear industry, providing capability for performing reactor physics, material research, and basic science experiments. Argonne National Laboratory (ANL) of USA is collaborating with KIPT on developing this facility. A driven subcritical assembly utilizing the KIPT electron accelerator with a target assembly is used to generate the neutron source. The target assembly utilizes tungsten or uranium for neutron production through photonuclear reactions with 100-KW of electron beam power. The neutron source intensity, spectrum, and spatial distribution have been studied to maximize the neutron yield and satisfy different engineering requirements. The subcritical assembly is designed to obtain the highest possible neutron flux intensity with a subcriticality of 0.98. Low enrichment uranium is used for the fuel material because it enhances the neutron source performance. Safety, reliability, and environmental considerations are included in the facility conceptual design. Horizontal neutron channels are incorporated for performing basic research including cold neutron source. This paper describes the conceptual design and summarizes some of the related analyses.

  7. Thermohydraulic behavior of the liquid metal target of a spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Y.

    1996-06-01

    The author presents work done on three main problems. (1) Natural circulation in double coaxial cylindircal container: The thermohydraulic behaviour of the liquid metal target of the spallation neutron source at PSI has been investigated. The configuration is a natural-circulation loop in a concentric double-tube-type container. The results show that the natural-circulation loop concept is valid for the design phase of the target construction, and the current specified design criteria will be fulfilled with the proposed parameter values. (2) Flow around the window: Water experiments were performed for geometry optimisation of the window shape of the SINQ container for avoiding generating recirculation zones at peripheral area and the optimal cooling of the central part of the beam entrance window. Flow visualisation technique was mainly used for various window shapes, gap distance between the window and the guide tube edge. (3) Flow in window cooling channels: Flows in narrow gaps of cooling channels of two different types of windows were studied by flow visualisation techniques. One type is a slightly curved round cooling channel and the other is hemispherical shape, both of which have only 2 mm gap distance and the water inlet is located on one side and flows out from the opposite side. In both cases, the central part of the flow area has lower velocity than peripheral area.

  8. Measurement of thick target neutron yields for protons and deuterons in Ten's of MeV region

    Energy Technology Data Exchange (ETDEWEB)

    Baba, M.; Aoki, T.; Kawata, N.; Hagiwara, M.; Miura, T.; Yamadera, A.; Yonai, S.; Nakamura, T. [Tohoku Univ., Sendai (Japan)

    2002-07-01

    We have measured energy-angular differential thick target neutron yields (TTY) for C, Al, Ta, W(p,n) reactions at 50 MeV, and Li, Be (d,n) reactions for 25 MeV deuterons with the TOF method using Tohoku University K=110 MeV cyclotron equipped with a beam swinger system and a well collimated TOF line. Neutron spectrum data have been obtained down to {approx} 0.8 MeV from the highest energy at several laboratory angles from 0-deg to 90-deg. The results are compared with other experiments and a recent data library LA-150.

  9. Design of High-Neutron-Yield, Polar-drive targets for diagnostic activation experiments on the NIF

    Energy Technology Data Exchange (ETDEWEB)

    McKenty, P W; Craxton, R S; Marshall, F J; Sangster, T C; Marozas, J A; Cok, A M; Bonino, M J; Harding, D R; Meyerhofer, D D; McCrory, R L [Laboratory for Laser Energetics, University of Rochester, 250 E. River Road, Rochester, NY 14623 (United States); Kilkenny, J D; Nikroo, A; Fooks, J; Hoppe, M L [General Atomics Corporation, La Jolla, CA (United States); Edwards, J M; MacKinnon, A J; Munro, D H; Wallace, R J, E-mail: pmck@lle.rochester.ed [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2010-08-01

    Polar-drive (PD) target implosions have been designed for neutron diagnostic development on the NIF. These experiments use thin, room-temperature glass shells filled with low pressures of DT. Initial target implosions on the NIF will produce DT yields in the range of a few 10{sup 14} neutrons. The predicted yields are consistent with earlier data (10{sup 14} neutrons at 30 kJ) and recent PD scoping experiments performed on OMEGA. The experiments will use existing x-ray-drive phase plates with judicious repointing and defocusing to drive the implosions as uniformly as possible. These implosions have been modeled with three codes: LILAC, to optimize the 1-D design; SAGE, to optimize the pointing uniformity; and DRACO, to predict the yield from 2-D implosion simulations. Current simulation results indicate that the required yields will be obtained using up to 200-kJ UV light formed into a 1500-ps Gaussian pulse. Large-diameter glass shells ({approx}1500-{mu}m OD) are under development and fabrication at General Atomics. As tritium and environmental conditions evolve, similar target designs, with larger diameters and higher laser energies, are expected to produce thermonuclear yields approaching 10{sup 16} neutrons.

  10. One-neutron knockout reaction of 17C on a hydrogen target at 70 MeV/nucleon

    CERN Document Server

    Satou, Y; Kim, S; Tshoo, K; Choi, S; Nakamura, T; Kondo, Y; Matsui, N; Hashimoto, Y; Nakabayashi, T; Okumura, T; Shinohara, M; Fukuda, N; Sugimoto, T; Otsu, H; Togano, Y; Motobayashi, T; Sakurai, H; Yanagisawa, Y; Aoi, N; Takeuchi, S; Gomi, T; Ishihara, M; Kawai, S; Ong, H J; Onishi, T K; Shimoura, S; Tamaki, M; Kobayashi, T; Matsuda, Y; Endo, N; Kitayama, M

    2014-01-01

    First experimental evidence of the population of the first 2- state in 16C above the neutron threshold is obtained by neutron knockout from 17C on a hydrogen target. The invariant mass method combined with in-beam gamma-ray detection is used to locate the state at 5.45(1) MeV. Comparison of its populating cross section and parallel momentum distribution with a Glauber model calculation utilizing the shell-model spectroscopic factor confirms the core-neutron removal nature of this state. Additionally, a previously known unbound state at 6.11 MeV and a new state at 6.28(2) MeV are observed. The position of the first 2- state, which belongs to a member of the lowest-lying p-sd cross shell transition, is reasonably well described by the shell-model calculation using the WBT interaction.

  11. Removal targets' classification: How time considerations modify the definition of the index

    Science.gov (United States)

    Zemoura, Mélissa; Hanada, Toshiya; Kawamoto, Satomi

    2017-09-01

    each future), and simulations are run once again, through different scenarios involving the removal of particular listed targets in order to verify the appropriateness of the proposed scenarios. The analysis of the results is based both on the mean of the simulations and on the recurrence considering each run. Three studies were conducted one for each term, and a fourth one completed the work by establishing comparison between short, mid and long-term periods. As a result, three main criteria could be established: the altitude of the objects, the number of targets necessary to remove, and the phenomenon of chain collisions. According to the future that was investigated, the most adequate criterion appeared to be different, consisting in the number of objects in the long-term analysis or the ranking position at short term (linked to the close-time consideration). As a main conclusion and further perspectives, it should be more efficient to consider the collision-probability and mass product together with the time-depending generation of fragments. This would help increasing the precision in the prediction of collision impacts. Rather than pinpointing specified targets to be removed, the aim of this study is simply to understand the mechanisms at the origin of the population increase around the Earth. Also to demonstrate that a careful definition of selection criteria would enable to adopt a suitable removal process in the period of action or for the goal to be reached.

  12. Pressure and stress waves in a spallation neutron source mercury target generated by high-power proton pulses

    CERN Document Server

    Futakawa, M; Conrad, H; Stechemesser, H

    2000-01-01

    The international ASTE collaboration has performed a first series of measurements on a spallation neutron source target at the Alternating Gradient Synchrotron (AGS) in Brookhaven. The dynamic response of a liquid mercury target hit by high-power proton pulses of about 40 ns duration has been measured by a laser Doppler technique and compared with finite elements calculations using the ABAQUS code. It is shown that the calculation can describe the experimental results for at least the time interval up to 100 mu s after the pulse injection. Furthermore, it has been observed that piezoelectric pressure transducers cannot be applied in the high gamma-radiation field of a spallation target.

  13. Measurements of neutron spectrum from stopping-length target irradiated by several tens-MeV/u particles

    Energy Technology Data Exchange (ETDEWEB)

    Meigo, Shin-ichiro; Takada, Hiroshi; Nakashima, Hiroshi; Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tanaka, Susumu; Shin, Kazuo; Ono, Shinji

    1997-03-01

    Using a Time-of-Flight technique, we have measured neutron spectra from stopping-length targets bombarded with 68-MeV protons and 100-MeV {alpha}-particles. The measured spectra were used to validate the results calculated by the Quantum Molecular Dynamics (QMD) plus Statistical Decay Model (SDM). The results of QMD plus SDM code agreed fairly well with the experimental data for the light target. On the other hand, the QMD plus SDM gives a larger value than the experimental for the heavy target. (author)

  14. Intracellular delivery and passive tumor targeting of a self-assembled nanogel containing carborane clusters for boron neutron capture therapy.

    Science.gov (United States)

    Kawasaki, Riku; Sasaki, Yoshihiro; Akiyoshi, Kazunari

    2017-01-29

    Boron neutron capture therapy, based on the release of thermal neutron irradiation from boron, is a targeted radiation therapy for cancer. Targeted and sufficient accumulation of boron in tumor cells to achieve cytotoxic efficacy and reduce off-target effects remains a challenge. Carborane has been investigated for use as a delivery agent in boron neutron capture therapy because of its high boron content and chemical stability; however, it is cytotoxic, making safe delivery difficult. The aim of this study was to investigate the potential of carborane-bearing pullulan nanogels to safely and effectively deliver boron to tumor cells in vitro and in vivo and, consequently, assess their potential as a boron neutron capture therapeutic. Murine fibrosarcoma cells (CMS5a) were used for in vitro investigations of nanogel cytotoxicity, cell uptake. A mouse fibrosarcoma xenograft model was used to investigate the bio-distribution of nanogels after intravenous administration. The nanogels produced no apparent cytotoxicity and underwent cell uptake in CMS5a cells after a 24 h incubation at up to 2000 μg/mL and 400 μg/mL, respectively. The internalized nanogels were localized around the nuclear membrane. The nanogels were administered intravenously to mice bearing fibrosarcoma xenografts. Nanogel tumor localization likely occurred through the enhanced permeation and retention effect. The nanogels successfully reduced the cytotoxicity of carborane, were internalized into tumor cells, acted as a dual-delivery therapeutic and accumulated in tumors in vivo. Consequently, they demonstrate significant potential as a boron neutron capture therapeutic. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Geant4 Simulation of A Multi-layered target for the Study of Neutron-Unbound Nuclei

    Science.gov (United States)

    Gueye, Paul; Freeman, Jessica; Frank, Nathan; Thoennessen, Michael; MONA Collaboration

    2013-10-01

    The MoNA/LISA setup at the National Superconducting Cyclotron Laboratory at Michigan State University has provided an avenue to study the nuclear structure of unbound states/nuclei at and beyond the neutron dripline for the past decade using secondary beams from the Coupled Cyclotron Facility. A new multi-layered Si/Be active target is being designed to specifically study neutron-unbound nuclei. In these experiments the decay energy is reconstructed from fragment-neutron coincidence measurements that are typically low in count rate. The multi-layered target will allow the use of thicker targets to increase the reaction rates, thus enabling to study currently out of reach nuclei such as 21C, 23C and 24N. The Geant4 Monte Carlo toolkit is currently used to model these physics processes within the multi-layered target and expected invariant mass distributions. A description of the experimental setup and simulation work will be discussed. This work is supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0000979.

  16. Q2 Evolution of the Neutron Spin Structure Moments using a 3He Target

    Energy Technology Data Exchange (ETDEWEB)

    M. Amarian; L. Auerbach; T. Averett; J. Berthot; P. Bertin; B. Bertozzi; T. Black; E. Brash; D. Brown; E. Burtin; J. Calarco; G. Cates; Z. Chai; J.P. Chen; Seon-ho Choi; E. Chudakov; E. Cisbani; C.W. de Jager; A. Deur; R. DiSalvo; S. Dieterich; P. Djawotho; M. Finn; K. Fissum; H. Fonvieille; S. Frullani; H. Gao; J. Gao; F. Garibaldi; A. Gasparian; S. Gilad; R. Gilman; A. Glamazdin; C. Glashausser; E. Goldberg; J. Gomez; V. Gorbenko; J.O. Hansen; B. Hersman; R. Holmes; G.M. Huber; E. Hughes; B. Humensky; S. Incerti; M. Iodice; S. Jensen; X. Jiang; C. Jones; G. Jones; M. Jones; C. Jutier; A. Ketikyan; I. Kominis; W. Korsch; K. Kramer; K. Kumar; G. Kumbartzki; M. Kuss; E. Lakuriqi; G. Laveissiere; J. Lerose; M. Liang; N. Liyanage; G. Lolos; S. Malov; J. Marroncle; K. McCormick; R. Mckeown; Z.E. Meziani; R. Michaels; J. Mitchell; Z. Papandreou; T. Pavlin; G.G. Petratos; D. Pripstein; D. Prout; R. Ransome; Y. Roblin; D. Rowntree; M. Rvachev; F. Sabatie; A. Saha; K. Slifer; P. Souder; T. Saito; S. Strauch; R. Suleiman; K. Takahashi; S. Teijiro; L. Todor; H. Tsubota; H. Ueno; G. Urciuoli; R. Van der Meer; P. Vernin; H. Voskanian; B. Wojtsekhowski; F. Xiong; W. Xu; J.C. Yang; B. Zhang; P. Zolnierczuk

    2004-01-01

    We have measured the spin structure functions g{sub 1} and g{sub 2} of {sup 3}He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.07 GeV off a polarized {sup 3}He target at a 15.5{sup o} scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q{sup 2} evolution of {Gamma}{sub 1}(Q{sup 2})=/int{sub 0}{sup 1} g{sub 1}(x,Q{sup 2}) dx, {Gamma}{sub 2}(Q{sup 2})=/int{sub 0}{sup 1} g{sub 2}(x,Q{sup 2}) dx and d{sub 2} (Q{sup 2}) = /int{sub 0}{sup 1} x {sup 2}[2g{sub 1}(x,Q{sup 2}) + 3g{sub 2}(x,Q{sup 2})] dx for the neutron in the range 0.1 GeV{sup 2} /leq Q{sup 2} /leq 0.9 GeV{sup 2} with good precision. {Gamma}{sub 1}(Q{sup 2}) displays a smooth variation from high to low Q{sup 2}. The Burkhardt-Cottingham sum rule holds within uncertainties and d{sub 2} is non-zero over the measured range.

  17. Q^2 Evolution of the Neutron Spin Structure Moments using a He-3 Target

    CERN Document Server

    Amarian, M; Averett, T; Berthot, J; Bertin, P; Bertozzi, B; Black, T; Brash, E J; Brown, D; Burtin, E; Calarco, J R; Cates, G D; Chai, Z; Chen, J P; Seonho Choi; Chudakov, E; Cisbani, E; De Jager, C W; Deur, A; Di Salvo, R; Dieterich, S; Djawotho, P; Finn, M; Fissum, K; Fonvieille, H; Frullani, S; Gao, H; Gao, J; Garibaldi, F; Gasparian, A; Gilad, S; Gilman, R; Glamazdin, A; Glashausser, C; Goldberg, E; Gómez, J; Gorbenko, V; Hansen, J O; Hersman, B; Holmes, R; Huber, G M; Hughes, E; Humensky, B; Incerti, S; Iodice, M; Jensen, S; Jiang, X; Jones, C; Jones, G; Jones, M; Jutier, C; Ketikyan, A; Kominis, I; Korsch, W; Krämer, K; Kumar, K; Kumbartzki, G; Kuss, M; Lakuriqi, E; Laveissière, G; Le Rose, J J; Liang, M; Liyanage, N K; Lolos, G J; Malov, S; Marroncle, J; McCormick, K; McKeown, R; Meziani, Z E; Michaels, R; Mitchell, J; Papandreou, Z; Pavlin, T; Petratos, G G; Pripstein, D; Prout, D L; Ransome, R; Roblin, Y; Rowntree, D; Rvachev, M M; Sabatie, F; Saha, A; Slifer, K J; Souder, P A; Saitô, T; Strauch, S; Suleiman, R; Takahashi, K; Teijiro, S; Todor, L; Tsubota, H; Ueno, H; Urciuoli, G M; Van der Meer, R L J; Vernin, P; Voskanyan, H; Wojtsekhowski, B B; Xiong, F; Xu, W; Yang, J C; Zhang, B; Zolnierczuk, P A

    2004-01-01

    We have measured the spin structure functions $g_1$ and $g_2$ of $^3$He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.07 GeV off a polarized $^3$He target at a 15.5$^{\\circ}$ scattering angle. Excitation energies covered the resonance and part of the deep inelastic regions. We have determined for the first time the $Q^2$ evolution of $\\Gamma_1(Q^2)=\\int_0^{1} g_1(x,Q^2) dx$, $\\Gamma_2(Q^2)=\\int_0^1 g_2(x,Q^2) dx$ and $d_2 (Q^2) = \\int_0^1 x^2[ 2g_1(x,Q^2) + 3g_2(x,Q^2)] dx$ for the neutron in the range 0.1 GeV$^2$ $\\leq Q^2 \\leq $ 0.9 GeV$^2$ with good precision. $ \\Gamma_1(Q^2)$ displays a smooth variation from high to low $Q^2$. The Burkhardt-Cottingham sum rule holds within uncertainties and $d_2$ is non-zero over the measured range.

  18. Studies on neutron production in the interaction of 7.4 GeV protons with extended lead target

    CERN Document Server

    Hashemi-Nezhad, S R; Ochs, M; Wan, J S; Schmidt, T; Langrock, E J; Vater, P; Adam, J; Bamblevskij, V P; Bradnova, V; Gelovani, L K; Kalinnikov, V K; Krivopustov, M I; Kulakov, B A; Sosnin, A N; Perelygin, V P; Pronskikh, V S; Stegailov, V I; Tsoupko-Sitnikov, V M; Modolo, G; Odoj, R; Phlippen, P W; Adloff, J C; Debeauvais, M; Zamani-Valassiadou, M; Dwivedi, K K; Wilson, B

    1999-01-01

    A cylindrical lead target of diameter 8 cm and length 20 cm was irradiated with 7.4 GeV protons along the axis of the cylinder. The lead target was surrounded with a paraffin layer of thickness 6 cm to moderate the neutrons produced in p + Pb reactions. The spatial distribution of the slow and fast neutrons on different surfaces of the moderator were determined using LR 115 2B detectors (through sup 1 sup 0 B(n,alpha) sup 7 Li reactions) and CR39 detectors (through proton recoils) respectively. Such results can be valuable in the studies and design of Accelerator Driven Subcritical Nuclear Reactors and Nuclear Waste Incinerators.

  19. Systematic analysis of neutron yields from thick targets bombarded by heavy ions and protons with moving source model

    CERN Document Server

    Kato, T; Nakamura, T

    2002-01-01

    A simple phenomenological analysis using the moving source model has been performed on the neutron energy spectra produced by bombarding thick targets with high energy heavy ions which have been systematically measured at the Heavy-Ion Medical Accelerator (HIMAC) facility (located in Chiba, Japan) of the National Institute of Radiological Sciences (NIRS). For the bombardment of both heavy ions and protons in the energy region of 100-500 MeV per nucleon, the moving source model incorporating the knock-on process could be generally successful in reproducing the measured neutron spectra within a factor of two margin of accuracy. This phenomenological analytical equation is expressed having several parameters as functions of atomic number Z sub p , mass number A sub p , energy per nucleon E sub p for projectile, and atomic number Z sub T , mass number A sub T for target. By inputting these basic data for projectile and target into this equation we can easily estimate the secondary neutron energy spectra at an emi...

  20. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  1. The BLAIRR Irradiation Facility Hybrid Spallation Target Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Simos N.; Hanson A.; Brown, D.; Elbakhshawn, M.

    2016-04-11

    BLAIRR STUDY STATUS OVERVIEW Beamline Complex Evaluation/Assessment and Adaptation to the Goals Facility Radiological Constraints ? Large scale analyses of conventional facility and integrated shield (concrete, soil)Target Optimization and Design: Beam-target interaction optimization Hadronic interaction and energy deposition limitations Single phase and Hybrid target concepts Irradiation Damage Thermo-mechanical considerations Spallation neutron fluence optimization for (a) fast neutron irradiation damage (b) moderator/reflector studies, (c) NTOF potential and optimization (d) mono-energetic neutron beam

  2. Neutron-induced transmutation reactions in 237Np, 238Pu, and 239Pu at the massive natural uranium spallation target

    Science.gov (United States)

    Zavorka, L.; Adam, J.; Baldin, A. A.; Caloun, P.; Chilap, V. V.; Furman, W. I.; Kadykov, M. G.; Khushvaktov, J.; Pronskikh, V. S.; Solnyshkin, A. A.; Sotnikov, V.; Stegailov, V. I.; Suchopar, M.; Tsoupko-Sitnikov, V. M.; Tyutyunnikov, S. I.; Voronko, V.; Vrzalova, J.

    2015-04-01

    Transmutation reactions in the 237Np, 238Pu, and 239Pu samples were investigated in the neutron field generated inside a massive (m = 512 kg) natural uranium spallation target. The uranium target assembly QUINTA was irradiated with the deuteron beams of kinetic energy 2, 4, and 8 GeV provided by the Nuclotron accelerator at the Joint Institute for Nuclear Research (JINR) in Dubna. The neutron-induced transmutation of the actinide samples was measured off-line by implementing methods of gamma-ray spectrometry with HPGe detectors. Results of measurement are expressed in the form of both the individual reaction rates and average fission transmutation rates. For the purpose of validation of radiation transport programs, the experimental results were compared with simulations of neutron production and distribution performed by the MCNPX 2.7 and MARS15 codes employing the INCL4-ABLA physics models and LAQGSM event generator, respectively. In general, a good agreement between the experimental and calculated reaction rates was found in the whole interval of provided beam energies.

  3. Cross Sections for Neutron-induced Reactions on Actinide Targets Extracted from Surrogate Experiments: A Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J E; Burke, J T; Dietrich, F S; Lesher, S R; Scielzo, N D; Thompson, I J; Younes, W

    2009-10-01

    The Surrogate nuclear reactions method, an indirect approach for determining cross sections for compound-nuclear reactions involving difficult-to-measure targets, is reviewed. Focusing on cross sections for neutron-induced reactions on actinides, we review the successes of past and present applications of the method and assess its uncertainties and limitations. The approximations used in the analyses of most experiments work reasonably well for (n,f) cross sections for neutron energies above 1-2 MeV, but lead to discrepancies for low-energy (n,f) reactions, as well as for (n,{gamma}) applications. Correcting for some of the effects neglected in the approximate analyses leads to improved (n,f) results. We outline steps that will further improve the accuracy and reliability of the Surrogate method and extend its applicability to reactions that cannot be approached with the present implementation of the method.

  4. Maximum proton kinetic energy and patient-generated neutron fluence considerations in proton beam arc delivery radiation therapy.

    Science.gov (United States)

    Sengbusch, E; Pérez-Andújar, A; DeLuca, P M; Mackie, T R

    2009-02-01

    Several compact proton accelerator systems for use in proton therapy have recently been proposed. Of paramount importance to the development of such an accelerator system is the maximum kinetic energy of protons, immediately prior to entry into the patient, that must be reached by the treatment system. The commonly used value for the maximum kinetic energy required for a medical proton accelerator is 250 MeV, but it has not been demonstrated that this energy is indeed necessary to treat all or most patients eligible for proton therapy. This article quantifies the maximum kinetic energy of protons, immediately prior to entry into the patient, necessary to treat a given percentage of patients with rotational proton therapy, and examines the impact of this energy threshold on the cost and feasibility of a compact, gantry-mounted proton accelerator treatment system. One hundred randomized treatment plans from patients treated with IMRT were analyzed. The maximum radiological pathlength from the surface of the patient to the distal edge of the treatment volume was obtained for 180 degrees continuous arc proton therapy and for 180 degrees split arc proton therapy (two 90 degrees arcs) using CT# profiles from the Pinnacle (Philips Medical Systems, Madison, WI) treatment planning system. In each case, the maximum kinetic energy of protons, immediately prior to entry into the patient, that would be necessary to treat the patient was calculated using proton range tables for various media. In addition, Monte Carlo simulations were performed to quantify neutron production in a water phantom representing a patient as a function of the maximum proton kinetic energy achievable by a proton treatment system. Protons with a kinetic energy of 240 MeV, immediately prior to entry into the patient, were needed to treat 100% of patients in this study. However, it was shown that 90% of patients could be treated at 198 MeV, and 95% of patients could be treated at 207 MeV. Decreasing the

  5. Some considerations concerning the role of the ius ad bellum in targeting

    NARCIS (Netherlands)

    Gill, T.D.; Ducheine, P.A.L.; Schmitt, M.N.; Osinga, F.P.B.

    2016-01-01

    This contribution examines the influence of the ius ad bellum upon the targeting process. Specifically, it will examine how the rules of international law relating to the permissibility of the use of force can and do influence the targeting of both objects and persons which constitute military objec

  6. Target thickness dependence of the Be(p,xn neutron energy spectrum

    Directory of Open Access Journals (Sweden)

    Rakopoulos V.

    2014-03-01

    Full Text Available We report on the current status of the analysis of an experiment performed at The Svedberg Laboratory, with the aim of investigating the produced neutron field by Be(p,xn converters of three different thicknesses with a 30 MeV proton beam. The neutron energy spectra were measured with the Time of Flight technique using a BC-501 liquid scintillator with good n-γ Pulse Shape Discrimination properties, while the detected events were recorded simultaneously by two Data AcQuisition systems. In this paper, we present the experimental setup, the analysis technique and some preliminary results.

  7. 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.

    Science.gov (United States)

    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.

  8. Spatial distribution of neutrons in paraffin moderator surrounding a lead target irradiated with protons at intermediate energies

    CERN Document Server

    Adam, J; Bradnova, V

    2002-01-01

    The distribution of neutrons emitted during the irradiation with 0.65, 1.0 and 1.5 GeV protons from a lead target (O / = 8 cm, l = 20 cm) and moderated by a surrounding paraffin moderator of 6 cm thick was studied with a radiochemical sensor along the beam axis on top of the moderator. Small sup 1 sup 3 sup 9 La-sensors of approximately 1 g were used to measure essentially the thermal neutron fluence at different depths near the surface: i.e., on top of the moderator, in 10 mm deep holes and in 20 mm deep holes. The reaction sup 1 sup 3 sup 9 La(n, gamma) sup 1 sup 4 sup 0 La (tau sub 1 sub / sub 2 = 40.27 h) was studied using standard procedures of gamma spectroscopy and data analysis. The neutron induced activity of sup 1 sup 4 sup 0 La increases strongly with the depth of the hole inside the moderator, its activity distribution along the beam direction on top of the moderator has its maximum about 10 cm downstream the entrance of the protons into the lead and the induced activity increases about linearity ...

  9. A Targeted Search for Point Sources of EeV Neutrons

    NARCIS (Netherlands)

    The Pierre Auger Collaboration, [No Value; Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fox, B. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Fuji, T.; Gaior, R.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q. D.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Islo, K.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, A. J.; Matthews, J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Ochilo, L.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Peters, C.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tartare, M.; Thao, N. T.; Theodoro, V. M.; Tiffenberg, J.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Whelan, B. J.; Widom, A.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.

    2014-01-01

    A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as ni

  10. A Targeted Search for Point Sources of EeV Neutrons

    NARCIS (Netherlands)

    The Pierre Auger Collaboration, [No Value; Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fox, B. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Fuji, T.; Gaior, R.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q. D.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Islo, K.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, A. J.; Matthews, J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Ochilo, L.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Peters, C.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tartare, M.; Thao, N. T.; Theodoro, V. M.; Tiffenberg, J.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Whelan, B. J.; Widom, A.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.

    2014-01-01

    A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as ni

  11. Performance of a plasma window for a high pressure differentially pumped deuterium gas target for mono-energetic fast neutron production - Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Beer, A. de; Hershcovitch, A.; Franklyn, C.B.; Straaten, S. van; Guzek, J. E-mail: jguzek@debeers.co.za

    2000-09-01

    The reactions D(d,n){sup 3}He and T(d,n){sup 4}He are frequently used for production of the mono-energetic or quasi mono-energetic neutron beams but successful applications are often limited by the intensity of the generated neutron beams. The development of a suitable neutron source for such applications as studies of resonance phenomena, fast neutron radiography, selective fast neutron activation, explosives and contraband detection and others, depends on the output ion current of the accelerator and the design of the target system. A practical solution for a high pressure gas target was previously developed and successfully implemented at De Beers Diamond Research Laboratory in Johannesburg (Guzek et al., 1999), but it is limited to applications using low (<20%) duty cycle accelerators. The concept of a plasma window for the separation of a high pressure gas target region and accelerator vacuum, that was originally developed by Hershcovitch (1995) for electron welding applications, may be suitable for operation with continuous wave accelerators at high particle current output. Preliminary test results, which have been performed with various gases (argon, helium and deuterium), indicate that implementation of the plasma window into a gas target system, for the production of intense mono-energetic fast neutron beams will be achievable.

  12. Isotopic Distributions of the l8N Fragmentation Products in Coincidence with Neutrons on Targets 197Au and 9Be

    Institute of Scientific and Technical Information of China (English)

    李湘庆; 江栋兴; 叶沿林; 华辉; 陈陶; 李智焕; 葛愉成; 王全进; 吴和宇; 靳根明; 段利敏; 肖志刚; 王宏伟; 李祖玉; 王素芳

    2002-01-01

    We present the experimental isotopic distributions of the 18 N projectile fragmentation products Li, Be,B and Cin coincidence with neutrons, as well as the inclusive ones on 197 Au and 9Be targets. In the framework of theabrasion-ablation model, these distributions are calculated for various nucleon density distributions of the projec-tile. The comparison with experimental isotopic distributions of the projectile-like fragments in coincidence withneutrons shows that the information on the nucleon density distribution of the 18N projectile can be extracted.

  13. Non-Targeted Effects and LET: Considerations for Earth and Space Research

    Science.gov (United States)

    Sowa, Marianne B.

    2016-01-01

    It is evident from reports in the literature that there are many confounding factors that are capable of modulating radiation-induced non-targeted responses such as the bystander effect and the adaptive response. It has even been suggested that the observation of non-targeted responses may not be universally observable for differing radiation qualities. Dr. William Morgan made many contributions to the study of radiation induced non-targeted effects and it is indeed this area of research where we first began our collaboration more than a decade ago. In this presentation, I will discuss elements of this journey together with a particular emphasis on the role of LET in non-targeted effects.

  14. Measurements of spallation neutrons from a thick lead target bombarded with 0.5 and 1.5 GeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Meigo, Shin-ichiro; Takada, Hiroshi; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1997-03-01

    Double differential neutron spectra from a thick lead target bombarded with 0.5 and 1.5 GeV protons have been measured with the time-of-flight technique. In order to obtain the neutron spectra without the effect of the flight time fluctuation by neutron scattering in the target, an unfolding technique has also been employed in the low energy region below 3 MeV. The measured data have been compared with the calculated results of NMTC/JAERI-MCNP-4A code system. It has been found that the code system gives about 50 % lower neutron yield than the experimental ones in the energy region between 20 and 80 MeV for both incident energies. The disagreements, however, have been improved well by taking account of the inmedium nucleon-nucleon scattering cross sections in the NMTC/JAERI code. (author)

  15. Radiological considerations on multi-MW targets. Part I: Induced radioactivity

    Science.gov (United States)

    Agosteo, S.; Magistris, M.; Silari, M.

    2005-06-01

    CERN is designing a Superconducting Proton Linac (SPL) to provide a 2.2 GeV, 4 MW proton beam to feed facilities like, for example, a future Neutrino Factory or a Neutrino SuperBeam. The material activation in such facilities is an important aspect that has to be taken into account at an early design stage. In particular, the choice of the target has consequences on the induced radioactivity and dose rates in the target itself and in its surroundings. In the present work, the radiological aspects of a stationary target made up of small tantalum pellets are compared to those of a free-surface jet of mercury. An estimation of the hadronic inelastic interactions and the production of residual nuclei in the target, the magnetic horn, the decay tunnel, the surrounding rock and a downstream dump were performed for both targets by the Monte Carlo hadronic cascade code FLUKA. The aim was to assess the dose equivalent rate to be expected during maintenance work and to evaluate the amount of residual radioactivity, which will have to be disposed of after the facility has ceased operation.

  16. Radiological considerations on multi-MW targets Part I Induced radioactivity

    CERN Document Server

    Agosteo, S; Silari, M

    2005-01-01

    CERN is designing a Superconducting Proton Linac (SPL) to provide a 2.2GeV, 4MW proton beam to feed facilities like, for example, a future Neutrino Factory or a Neutrino SuperBeam. The material activation in such facilities is an important aspect that has to be taken into account at an early design stage. In particular, the choice of the target has consequences on the induced radioactivity and dose rates in the target itself and in its surroundings. In the present work, the radiological aspects of a stationary target made up of small tantalum pellets are compared to those of a free-surface jet of mercury. An estimation of the hadronic inelastic interactions and the production of residual nuclei in the target, the magnetic horn, the decay tunnel, the surrounding rock and a downstream dump were performed for both targets by the Monte Carlo hadronic cascade code FLUKA. The aim was to assess the dose equivalent rate to be expected during maintenance work and to evaluate the amount of residual radioactivity, which...

  17. Biopharmaceutical considerations and characterizations in development of colon targeted dosage forms for inflammatory bowel disease.

    Science.gov (United States)

    Malayandi, Rajkumar; Kondamudi, Phani Krishna; Ruby, P K; Aggarwal, Deepika

    2014-04-01

    Colon targeted dosage forms have been extensively studied for the localized treatment of inflammatory bowel disease. These dosage forms not only improve the therapeutic efficacy but also reduce the incidence of adverse drug reactions and hence improve the patient compliance. However, complex and highly variable gastro intestinal physiology limits the clinical success of these dosage forms. Biopharmaceutical characteristics of these dosage forms play a key role in rapid formulation development and ensure the clinical success. The complexity in product development and clinical success of colon targeted dosage forms are based on the biopharmaceutical characteristics such as physicochemical properties of drug substances, pharmaceutical characteristics of dosage form, physiological conditions and pharmacokinetic properties of drug substances as well as drug products. Various in vitro and in vivo techniques have been employed in past to characterize the biopharmaceutical properties of colon targeted dosage forms. This review focuses on the factors influencing the biopharmaceutical performances of the dosage forms, in vitro characterization techniques and in vivo studies.

  18. Radiological considerations on multi-MW targets Part II After-heat and temperature distribution in packed tantalum spheres

    CERN Document Server

    Magistris, M

    2005-01-01

    CERN is designing a Superconducting Proton Linac (SPL) to provide a 2.2GeV, 4MW proton beam to feed facilities like, for example, a future Neutrino Factory or a Neutrino SuperBeam. One of the most promising target candidates is a stationary consisting of a Ti container filled with small Ta pellets. The power deposited as heat by the radioactive nuclides (the so-called after-heat) can considerably increase the target temperature after ceasing operation, if no active cooling is provided. An estimate of the induced radioactivity and after-heat was performed with the FLUKA Monte Carlo code. To estimate the highest temperature reached inside the target, the effective thermal conductivity of packed spheres was evaluated using the basic cell method. A method for estimating the contribution to heat transmission from radiation is also discussed1).

  19. Consideration of R2Fe14B layers as targets with polarized electrons

    NARCIS (Netherlands)

    Hoogduin, JM; van Klinken, J

    1998-01-01

    Thin layers of R2Fe14B magnets (R = rare earth) can be magnetized perpendicularly to their planes and can be used as targets of polarized electrons with polarization of approximate to 4% to facilitate Moller/Bhabha and Compton polarimetry of electrons/positrons and photons, respectively. (C) 1998 El

  20. Marketing Climate: New Considerations for Target Marketing in Graduate Student Enrollment Management

    Science.gov (United States)

    Kranzow, Jeannine; Hyland, Nancy

    2011-01-01

    Lewison and Hawes (1997) discuss target marketing strategies of differentiated, concentrated or orchestrated marketing in their article "Student Marketing Strategies for Universities." While the authors agree with some of the suggested strategies and reasons behind them, their perspective as faculty teaching in a graduate education program offers…

  1. Consideration of R2Fe14B layers as targets with polarized electrons

    NARCIS (Netherlands)

    Hoogduin, JM; van Klinken, J

    1998-01-01

    Thin layers of R2Fe14B magnets (R = rare earth) can be magnetized perpendicularly to their planes and can be used as targets of polarized electrons with polarization of approximate to 4% to facilitate Moller/Bhabha and Compton polarimetry of electrons/positrons and photons, respectively. (C) 1998 El

  2. Consideration of R2Fe14B layers as targets with polarized electrons

    NARCIS (Netherlands)

    Hoogduin, JM; van Klinken, J

    Thin layers of R2Fe14B magnets (R = rare earth) can be magnetized perpendicularly to their planes and can be used as targets of polarized electrons with polarization of approximate to 4% to facilitate Moller/Bhabha and Compton polarimetry of electrons/positrons and photons, respectively. (C) 1998

  3. Neutronic and Thermal-Hydraulic Safety Analysis for the Optimization of the Uranium Foil Target in the RSG-GAS Reactor

    Directory of Open Access Journals (Sweden)

    S. Pinem

    2016-12-01

    Full Text Available The G. A. Siwabessy Multipurpose Reactor (Reaktor Serba Guna G.A. Siwabessy, RSG-GAS has an average thermal neutron flux of 2×1014 neutron/(cm2 sec at the nominal power of 30 MW. With such a high thermal neutron flux, the reactor is suitable for the production of Mo-99 which is widely used as a medical diagnostic radioisotope. This paper describes a safety analysis to determine the optimum LEU foil target by using a coupled neutronic and thermal-hydraulic code, MTR-DYN. The code has been developed based on the three-dimensional multigroup neutron diffusion theory. The best estimated results can be achieved by using a coupled neutronic and thermal-hydraulic code. The calculation results show that the optimum LEU foil target is 54 g corresponding to the reactivity change of less than the limit value of 500 pcm. From the safety analysis for the case when the primary flow rate decreased by 15% from its nominal value, it was found that the peak temperatures of the coolant and cladding are 69.5°C and 127.9°C, respectively. It can be concluded that the optimum LEU foil target can be irradiated safely without exceeding the limit value.

  4. 90 deg.Neutron emission from high energy protons and lead ions on a thin lead target

    CERN Document Server

    Agosteo, S; Foglio-Para, A; Mitaroff, W A; Silari, Marco; Ulrici, L

    2002-01-01

    The neutron emission from a relatively thin lead target bombarded by beams of high energy protons/pions and lead ions was measured at CERN in one of the secondary beam lines of the Super Proton Synchrotron for radiation protection and shielding calculations. Measurements were performed with three different beams: sup 2 sup 0 sup 8 Pb sup 8 sup 2 sup + lead ions at 40 GeV/c per nucleon and 158 GeV/c per nucleon, and 40 GeV/c mixed protons/pions. The neutron yield and spectral fluence per incident ion on target were measured at 90 deg.with respect to beam direction. Monte-Carlo simulations with the FLUKA code were performed for the case of protons and pions and the results found in good agreement with the experimental data. A comparison between simulations and experiment for protons, pions and lead ions have shown that--for such high energy heavy ion beams--a reasonable estimate can be carried out by scaling the result of a Monte-Carlo calculation for protons by the projectile mass number to the power of 0.80-0...

  5. Thermal analysis and neutron production characteristics of a low power copper beam dump-cum-target for LEHIPA

    Science.gov (United States)

    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.

  6. Status of R&D on mitigating the effects of pressure waves for the Spallation Neutron Source mercury target

    Science.gov (United States)

    Riemer, Bernard W.; Wendel, Mark W.; Felde, David K.; Abdou, Ashraf A.; McClintock, David A.

    2012-12-01

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory has been conducting R&D on mitigating the effects of pressure waves in mercury spallation targets since 2001. More precisely, cavitation damage of the target vessel caused by the short beam pulse threatens to limit its lifetime more severely than radiation damage as well as limit its ultimate power capacity - and hence its neutron intensity performance. The R&D program has moved from verification of the beam-induced damage phenomena to study of material and surface treatments for damage resistance to the current emphasis on gas injection techniques for damage mitigation. Two techniques are being worked on: injection of small dispersed gas bubbles that mitigate the pressure waves volumetrically; and protective gas walls that isolate the vessel from the damaging effects of collapsing cavitation bubbles. The latter has demonstrated good damage mitigation during in-beam testing with limited pulses, and adequate gas wall coverage at the beam entrance window has been demonstrated with the SNS mercury target flow configuration using a full scale mercury test loop. A question on the required area coverage remains which depends on results from SNS target post irradiation examination. The small gas bubble technique has been less effective during past in-beam tests but those results were with un-optimized and un-verified bubble populations. Another round of in-beam tests with small gas bubbles is planned for 2011. The first SNS target was removed from service in mid 2009 and samples were cut from two locations at the target's beam entrance window. Through-wall damage was observed at the innermost mercury vessel wall (not a containment wall). The damage pattern suggested correlation with the local mercury flow condition which is nearly stagnant at the peak damage location. Detailed post irradiation examination of the samples is under way that will assess the erosion and measure irradiation-induced changes

  7. Status of R and D on mitigating the effects of pressure waves for the Spallation Neutron Source mercury target

    Energy Technology Data Exchange (ETDEWEB)

    Riemer, Bernard W., E-mail: riemerbw@ornl.gov [Spallation Neutron Source/Oak Ride National Laboratory, P.O. Box 2008, Bldg. 8600, MS 6466, Oak Ridge, TN 37831 (United States); Wendel, Mark W.; Felde, David K.; Abdou, Ashraf A.; McClintock, David A. [Spallation Neutron Source/Oak Ride National Laboratory, P.O. Box 2008, Bldg. 8600, MS 6466, Oak Ridge, TN 37831 (United States)

    2012-12-15

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory has been conducting R and D on mitigating the effects of pressure waves in mercury spallation targets since 2001. More precisely, cavitation damage of the target vessel caused by the short beam pulse threatens to limit its lifetime more severely than radiation damage as well as limit its ultimate power capacity - and hence its neutron intensity performance. The R and D program has moved from verification of the beam-induced damage phenomena to study of material and surface treatments for damage resistance to the current emphasis on gas injection techniques for damage mitigation. Two techniques are being worked on: injection of small dispersed gas bubbles that mitigate the pressure waves volumetrically; and protective gas walls that isolate the vessel from the damaging effects of collapsing cavitation bubbles. The latter has demonstrated good damage mitigation during in-beam testing with limited pulses, and adequate gas wall coverage at the beam entrance window has been demonstrated with the SNS mercury target flow configuration using a full scale mercury test loop. A question on the required area coverage remains which depends on results from SNS target post irradiation examination. The small gas bubble technique has been less effective during past in-beam tests but those results were with un-optimized and un-verified bubble populations. Another round of in-beam tests with small gas bubbles is planned for 2011. The first SNS target was removed from service in mid 2009 and samples were cut from two locations at the target's beam entrance window. Through-wall damage was observed at the innermost mercury vessel wall (not a containment wall). The damage pattern suggested correlation with the local mercury flow condition which is nearly stagnant at the peak damage location. Detailed post irradiation examination of the samples is under way that will assess the erosion and measure irradiation

  8. Status of R&D on Mitigating the Effects of Pressure Waves for the Spallation Neutron Source Mercury Target

    Energy Technology Data Exchange (ETDEWEB)

    Riemer, Bernie [ORNL; Wendel, Mark W [ORNL; Felde, David K [ORNL; Abdou, Ashraf A [ORNL; McClintock, David A [ORNL

    2012-01-01

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory has been conducting R&D on mitigating the effects of pressure waves in mercury spallation targets since 2001. More precisely, cavitation damage of the target vessel caused by the short beam pulse threatens to limit its lifetime more severely than radiation damage as well as limit its ultimate power capacity and hence its neutron intensity performance. The R&D program has moved from verification of the beam-induced damage phenomena to study of material and surface treatments for damage resistance to the current emphasis on gas injection techniques for damage mitigation. Two techniques are being worked on: injection of small dispersed gas bubbles that mitigate the pressure waves volumetrically; and protective gas walls that isolate the vessel from the damaging effects of collapsing cavitation bubbles. The latter has demonstrated good damage mitigation during in-beam testing with limited pulses, and adequate gas wall coverage at the beam entrance window has been demonstrated with the SNS mercury target flow configuration using a full scale mercury test loop. A question on the required area coverage remains which depends on results from SNS target post irradiation examination. The small gas bubble technique has been less effective during past in-beam tests but those results were with un-optimized and un-verified bubble populations. Another round of in-beam tests with small gas bubbles is planned for 2011. The first SNS target was removed from service in mid 2009 and samples were cut from two locations at the target s beam entrance window. Through-wall damage was observed at the innermost mercury vessel wall (not a containment wall). The damage pattern suggested correlation with the local mercury flow condition which is nearly stagnant at the peak damage location. Detailed post irradiation examination of the samples is under way that will assess the erosion and measure irradiation-induced changes

  9. Neuronal nicotinic receptors as novel targets for inflammation and neuroprotection:mechanistic considerations and clinical relevance

    Institute of Scientific and Technical Information of China (English)

    Merouane BENGHEKIF

    2009-01-01

    A number of studies have confirmed the potential for neuronal nicotinic acetylcholine receptor (NNR)-mediated neuro- protection and, more recently, its anti-inflammatory effects. The mechanistic overlap between these pathways and the ubiquitous effects observed following diverse insults suggest that NNRs modulate fundamental pathways involved in cell survival. These results have wide-reaching implications for the design of experimental therapeutics that regulate inflamma- tory and anti-apoptotic responses through NNRs and represent an initial step toward understanding the benefits of novel therapeutic strategies for the management of central nervous system disorders that target neuronal survival and associated inflammatory processes.

  10. Molecular Pathways: New Signaling Considerations When Targeting Cytoskeletal Balance to Reduce Tumor Growth.

    Science.gov (United States)

    Chakrabarti, Kristi R; Hessler, Lindsay; Bhandary, Lekhana; Martin, Stuart S

    2015-12-01

    The dynamic balance between microtubule extension and actin contraction regulates mammalian cell shape, division, and motility, which has made the cytoskeleton an attractive and very successful target for cancer drugs. Numerous compounds in clinical use to reduce tumor growth cause microtubule breakdown (vinca alkaloids, colchicine-site, and halichondrins) or hyperstabilization of microtubules (taxanes and epothilones). However, both of these strategies indiscriminately alter the assembly and dynamics of all microtubules, which causes significant dose-limiting toxicities on normal tissues. Emerging data are revealing that posttranslational modifications of tubulin (detyrosination, acetylation) or microtubule-associated proteins (Tau, Aurora kinase) may allow for more specific targeting of microtubule subsets, thereby avoiding the broad disruption of all microtubule polymerization. Developing approaches to reduce tumor cell migration and invasion focus on disrupting actin regulation by the kinases SRC and ROCK. Because the dynamic balance between microtubule extension and actin contraction also regulates cell fate decisions and stem cell characteristics, disrupting this cytoskeletal balance could yield unexpected effects beyond tumor growth. This review will examine recent data demonstrating that cytoskeletal cancer drugs affect wound-healing responses, microtentacle-dependent reattachment efficiency, and stem cell characteristics in ways that could affect the metastatic potential of tumor cells, both beneficially and detrimentally. ©2015 American Association for Cancer Research.

  11. Parental Factors Associated with Child Post-traumatic Stress Following Injury: A Consideration of Intervention Targets

    Directory of Open Access Journals (Sweden)

    Anna E. Wise

    2017-08-01

    Full Text Available Post-traumatic stress disorder (PTSD symptoms are relatively common following pediatric traumatic injury and are related to poor long-term child outcomes. However, due to concerns regarding the efficacy of early child preventive interventions, and difficulty intervening with injured and medicated children soon after the event, it is not feasible to provide early psychological interventions to children exposed to traumatic injury. Parental PTSD symptoms and reactions to the child’s traumatic injury impact child outcomes and provide potential targets for early intervention to reduce child symptom development without involving the child. The authors conducted a review of the literature using Psycinfo and Pubmed research databases (publication years = 1990–2017 and identified 65 published studies relevant to the topic of the review. The present review considers parent factors [parenting styles, parental post-traumatic pathology (PTS, adaptive and maladaptive coping strategies, and communication regarding the traumatic injury] and their impact on child PTS. We focus specifically on factors amenable to intervention. We further review moderators of these relationships (e.g., child age and gender, parent gender and conclude that it is unlikely that a one-size-fits-all approach to treatment will be successful. Rather, it is necessary to consider the age and gender of parent child dyads in designing and providing targeted interventions to families following the traumatic injury of a child.

  12. MONTE CARLO MODEL FOR NEUTRON PRODUCTION BY THE INTERACTIONS OF LOW ENERGY DEUTERONS IN SOLID TARGETS

    OpenAIRE

    Milocco, Alberto

    2012-01-01

    The construction of the nuclear fusion plant 'ITER' has started in 2009 at Cadarache, France. The ITER machine represents a milestone in the civil use of the nuclear fusion energy. The physics of ITER is based on the fusion reaction between deuteron and triton nuclei (d-t). The deuteron-deuteron reaction (d-d) is also interesting and is foreseen for the next generation of fusion reactors. The experimental activities carried out in the context of the ITER neutronics involve intense fields of n...

  13. Parallel computation safety analysis irradiation targets fission product molybdenum in neutronic aspect using the successive over-relaxation algorithm

    Science.gov (United States)

    Susmikanti, Mike; Dewayatna, Winter; Sulistyo, Yos

    2014-09-01

    One of the research activities in support of commercial radioisotope production program is a safety research on target FPM (Fission Product Molybdenum) irradiation. FPM targets form a tube made of stainless steel which contains nuclear-grade high-enrichment uranium. The FPM irradiation tube is intended to obtain fission products. Fission materials such as Mo99 used widely the form of kits in the medical world. The neutronics problem is solved using first-order perturbation theory derived from the diffusion equation for four groups. In contrast, Mo isotopes have longer half-lives, about 3 days (66 hours), so the delivery of radioisotopes to consumer centers and storage is possible though still limited. The production of this isotope potentially gives significant economic value. The criticality and flux in multigroup diffusion model was calculated for various irradiation positions and uranium contents. This model involves complex computation, with large and sparse matrix system. Several parallel algorithms have been developed for the sparse and large matrix solution. In this paper, a successive over-relaxation (SOR) algorithm was implemented for the calculation of reactivity coefficients which can be done in parallel. Previous works performed reactivity calculations serially with Gauss-Seidel iteratives. The parallel method can be used to solve multigroup diffusion equation system and calculate the criticality and reactivity coefficients. In this research a computer code was developed to exploit parallel processing to perform reactivity calculations which were to be used in safety analysis. The parallel processing in the multicore computer system allows the calculation to be performed more quickly. This code was applied for the safety limits calculation of irradiated FPM targets containing highly enriched uranium. The results of calculations neutron show that for uranium contents of 1.7676 g and 6.1866 g (× 106 cm-1) in a tube, their delta reactivities are the still

  14. Technical and dosimetric considerations in IMRT treatment planning for large target volumes.

    Science.gov (United States)

    Malhotra, Harish K; Raina, Sanjay; Avadhani, Jaiteerth S; deBoer, Steven; Podgorsak, Matthew B

    2005-01-01

    The maximum width of an intensity-modulated radiotherapy (IMRT) treatment field is usually smaller than the conventional maximum collimator opening because of design limitations inherent in some multileaf collimators (MLCs). To increase the effective field width, IMRT fluences can be split and delivered with multiple carriage positions. However, not all treatment-planning systems and MLCs support this technique, and if they do, the maximum field width in multiple carriage position delivery is still significantly less than the maximum collimator opening. For target volumes with dimensions exceeding the field size limit for multiple carriage position delivery, such as liver tumors or other malignancies in the abdominal cavity, IMRT treatment can be accomplished with multiple isocenters or with an extended treatment distance. To study dosimetric statistics of large field IMRT planning, an elliptical volume was chosen as a target within a cubic phantom centered at a depth of 7.5 cm. Multiple three-field plans (one AP and two oblique beams with 160 degrees between them to avoid parallel opposed geometry) with constraints designed to give 100% dose to the elliptical target were developed. Plans were designed with a single anterior field with dual carriage positions, or with the anterior field split into two fields with separate isocenters 8 cm apart with the beams being forcibly matched at the isocenter or with a 1 cm, 2 cm, 3 cm, and 4 cm overlap. The oblique beams were planned with a single carriage position in all cases. All beams had a nominal energy of 6 MV. In the dual isocenter plans, jaws were manually fixed and dose constraints remained unaltered. Dosimetric statistics were studied for plans developed for treatment delivery using both dynamic leaf motion (sliding window) and multiple static segments (step and shoot) with the number of segments varying from 5 to 30. All plans were analyzed based on the dose homogeneity in the isocenter plane, 2 cm anterior and 2

  15. OUTPUT VOLATILITY AND EXCHANGE RATE CONSIDERATIONS UNDER INFLATION TARGETING : A REVIEW

    Directory of Open Access Journals (Sweden)

    Marjan Petreski

    2012-01-01

    Full Text Available The objective of the paper is to offer a critique on the theoretical and empirical literature on inflation targeting (IT. It seems to exist a consensus in the theoretical literature that this monetary regime reduces both inflation and output volatility, mainly through building monetary policy credibility. When the role of the exchange rate is discussed, while there are some arguments that, as an instrument, it should not be explicitly stated in the central-bank loss function, theoretical arguments and evidence are still mixed as regards the effectiveness of exchange-rate management under IT. On the empirical front, the paper concludes that despite the fact that the work on IT in the last two decades has been immense in quality and quantity, still there is no quantitatively-credible study for the developing world, let alone a study that appropriately measures the regime switch from one monetary strategy to another.

  16. Considerations Concerning the Application of Target Costing Method in the Industry of Dairy Products

    Directory of Open Access Journals (Sweden)

    Mortură Laura Alexandra

    2017-01-01

    Full Text Available In the present conditions of the market economy, which is in full process of globalization, theadaptation of the more complex and diverse needs of the final consumers, leads to a permanentcreation and development of new products and services by the entities in order to satisfy theseneeds. Thus, the entities must apply efficient and tested methods for determining and provisioningthe costs which will result from launching new products on the market, methods which wouldsupport and ensure the best quality – price report, and which are to reduce the production costs upto a level of not affecting the quality of the final product. Such a method, according to specialtyliterature is the modern method of Target Costing.

  17. Gamma Knife and LINAC-Based Stereotactic Treatments of Intracranial Targets: Dosimetric and Radiobiological Considerations

    Science.gov (United States)

    Kendall, Ethan Lee

    The scientific community is interested in furthering the understanding of shock wave structures in water, given its implications in a wide range of applications; from researching how shock waves penetrate unwanted body tissues to studying how humans respond to blast waves. Shock wave research on water has existed for over five decades. Previous studies have investigated the shock response of water at pressures ranging from 1 to 70 GPa using flyer plate experiments. This report differs from previously published experiments in that the water was loaded to shock pressures ranging from 0.36 to 0.70 GPa. The experiment also utilized tap water rather than distilled water as the test sample. Flyer plate experiments were conducted in the Shock Physics Laboratory at Marquette University to determine the structure of shock waves within water. A 12.7 mm bore gas gun fired a projectile made of copper, PMMA, or aluminum at a stationary target filled with tap water. Graphite break pins in a circuit determined the initial projectile velocity prior to coming into contact with the target. A Piezoelectric timing pin (PZT pin) at the front surface of the water sample determined the arrival of the leading wave and a Photon Doppler Velocimeter (PDV) measured particle velocity from the rear surface of the water sample. The experimental results were compared to simulated data from a Eulerian Hydrocode called CTH [1]. The experimental results differed from the simulated results with deviations believed to be from experimental equipment malfunctions. The main hypothesis being that the PZT pin false triggered, resulting in measured lower than expected shock velocities. The simulated results were compared to published data from various authors and was within range.

  18. Measurements of attenuation lengths through concrete and iron for neutrons produced by 800-MeV proton on tantalum target at ISIS

    CERN Document Server

    Nunomiya, T; Wright, P; Nakamura, T; Kim, E; Kurosawa, T; Taniguchi, S; Sasaki, M; Iwase, H; Uwamino, Y; Shibata, T; Ito, S; Perry, D R

    2002-01-01

    A deep penetration experiment through a thick bulk shield was performed at an intense spallation neutron source facility, ISIS, of the Rutherford Appleton Laboratory (RAL), United Kingdom. ISIS is a 800 MeV-200 mu A proton accelerator facility. Neutrons are produced from a tantalum target, and are shielded with approximately 3-m thick steel and 1-m thick ordinary concrete. On top of the shield, we measured the neutron flux attenuation through concrete and iron shields, which were additionally placed up to 120-cm and 60-cm thickness, respectively, using activation detectors of graphite and bismuth. The attenuation lengths of concrete and iron for high-energy neutrons above 20 MeV were obtained from the sup 1 sup 2 C(n, 2n) sup 1 sup 1 C reaction of graphite.

  19. Preliminary shielding analysis in support of the CSNS target station shutter neutron beam stop design%Preliminary shielding analysis in support of the CSNS target station shutter neutron beam stop design

    Institute of Scientific and Technical Information of China (English)

    张斌; 陈义学; 王伟金; 杨寿海; 吴军; 殷雯; 梁天骄; 贾学军

    2011-01-01

    The construction of China Spallation Neutron Source (CSNS) has been initiated in Dongguan, Guangdong, China. Thus a detailed radiation transport analysis of the shutter neutron beam stop is of vital importance. The analyses are performed using the coupled

  20. Targeted inhibition of the FGF19-FGFR4 pathway in hepatocellular carcinoma; translational safety considerations.

    Science.gov (United States)

    Mellor, Howard R

    2014-07-01

    Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death and new therapies are urgently required to treat this disease. Recent data suggest that the FGF19-FGFR4 axis may be a key driver in certain forms of HCC, making the pathway an interesting, emerging molecular target for potential therapeutic intervention. A complication is that, outside of malignant disease, FGFR4 plays an important physiological role in the regulation of hepatic bile acid (BA) synthesis. FGF19 signalling via FGFR4 suppresses de novo BA production in the liver, tightly maintaining hepatic and systemic levels of these detergent-like molecules at a physiological threshold and preventing pathological complications of raised BA levels, such as cholestatic liver injury and bile acid diarrhoea. In some cases of HCC, the malignant disease causes bile duct obstruction, preventing BA secretion from the liver and resulting in cholestasis. Here, the role of FGFR4 signalling in both HCC and BA homoeostasis is discussed. The potential effects of therapeutic FGF19-FGFR4 inhibition on human hepatobiliary/gastrointestinal physiology are considered along with the potential safety implications of FGF19-FGFR4 blockade in patients with HCC.

  1. Neutronic effects on tungsten-186 double neutron capture

    Science.gov (United States)

    Garland, Marc Alan

    Rhenium-188, a daughter product of tungsten-188, is an isotope of great interest in therapeutic nuclear medicine, being used in dozens of laboratory and clinical investigations worldwide. Applications include various cancer therapy strategies, treatment of rheumatoid arthritis, prevention of restenosis following coronary artery angioplasty, and palliation of bone pain associated with cancer metastases. With its half-life of 17 hours, 2.12 MeV (maximum) beta-particle emission, chemical similarity to technetium-99m (the most widely used diagnostic radioisotope), and its availability in a convenient tungsten-188/rhenium-188 generator system, rhenium-188 is a superb candidate for a broad range of applications. Production of 188W is typically via double neutron capture by 186W in a high flux nuclear reactor, predominantly the High Flux Isotope Reactor at the Oak Ridge National Laboratory in Tennessee. Experience at HFIR has shown that production yields (measured in Ci of 188W produced per g of 186W target) decrease considerably as target size increases. While the phenomenon of neutron resonance self-shielding would be expected to produce such an effect, temperature effects on neutron flux distribution and neutron capture rates may also be involved. Experimental investigations of these phenomena have not been previously performed. The work presented in this thesis evaluates the factors that contribute to the decrease in 188W yield from both theoretical and experimental standpoints. Neutron self-shielding and temperature effects were characterized to develop a strategy for target design that would optimize production yield, an important factor in minimizing health care costs. It was determined that decrease in yield due to neutron self-shielding can be attributed to depletion of epithermal neutrons at resonant energies, most significantly within the initial 0.4 mm depth of the target. The results from these studies further show that 188W yield in the interior of the

  2. Transmutation of 129I, 237Np, 238Pu, 239Pu, and 241Am using neutrons produced in target-blanket system `Energy plus Transmutation' by relativistic protons

    Indian Academy of Sciences (India)

    J Adam; K Katovsky; A Balabekyan; V G Kalinnikov; M I Krivopustov; H Kumawat; A A Solnyshkin; V I Stegailov; S G Stetsenko; V M Tsoupko-Sitnikov; W Westmeier

    2007-02-01

    Target-blanket facility `Energy + Transmutation' was irradiated by proton beam extracted from the Nuclotron Accelerator in Laboratory of High Energies of Joint Institute for Nuclear Research in Dubna, Russia. Neutrons generated by the spallation reactions of 0.7, 1.0, 1.5 and 2 GeV protons and lead target interact with subcritical uranium blanket. In the neutron field outside the blanket, radioactive iodine, neptunium, plutonium and americium samples were irradiated and transmutation reaction yields (residual nuclei production yields) have been determined using -spectroscopy. Neutron field's energy distribution has also been studied using a set of threshold detectors. Results of transmutation studies of 129I, 237Np, 238Pu, 239Pu and 241Am are presented.

  3. Neutrons production during the interaction of monoenergetic electrons with a thin tungsten target; Produccion de neutrones durante la interaccion de electrones monoenergeticos con un blanco delgado de tungsteno

    Energy Technology Data Exchange (ETDEWEB)

    Soto B, T. G.; Medina C, D. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Programa de Doctorado en Ciencias Basicas, 98068 Zacatecas, Zac. (Mexico); Baltazar R, A. [Universidad Autonoma de Zacatecas, Unidad Academica de Ingenieria Electrica, Programa de Doctorado en Ingenieria y Tecnologia Aplicada, 98068 Zacatecas, Zac. (Mexico); Vega C, H. R., E-mail: tzinnia.soto@gmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2016-10-15

    When a linear accelerator for radiotherapy operates with acceleration voltages higher than 8 MV, neutrons are produced, as secondary radiation which deposits an undesirable and undesirable dose in the patient. Depending on the type of tumor, its location in the body and the characteristics of the patient, the cancer treatment with a Linac is performed with photon or electron beams, which produce neutrons through reactions (γ, n) and (e, e n) respectively. Because the effective section for the neutrons production by reactions (γ, n) is approximately two orders of magnitude larger than the effective section of the reactions (e, e n), studies on the effects of this secondary radiation have focused on photo neutrons. en a Linac operates with electron beams, the beam coming out of the magnetic deflector is impinged on the dispersion lamella in order to cause quasi-elastic interactions and to expand the spatial distribution of the electrons; the objective of this work is to determine the characteristics of the photons and neutrons that occur when a mono-energetic electron beam of 2 mm in diameter (pencil beam) is made to impinge on a tungsten lamella of 1 cm in diameter and 0.5 mm of thickness. The study was done using Monte Carlo methods with code MCNP6 for electron beams of 8, 10, 12, 15 and 18 MeV. The spectra of photons and neutrons were estimated in 4 point detectors placed at different equidistant points from the center of the lamella. (Author)

  4. Measurement of the High Energy Neutron Flux on the Surface of the Natural Uranium Target Assembly QUINTA Irradiated by Deuterons of 4 and 8 GeV Energy

    Science.gov (United States)

    Adam, J.; Baldin, A. A.; Chilap, V.; Furman, W.; Katovsky, K.; Khushvaktov, J.; Kumar, V.; Pronskikh, V.; Mar'in, I.; Solnyshkin, A.; Suchopar, M.; Tsupko-Sitnikov, V.; Tyutyunnikov, S.; Vrzalova, J.; Wagner, V.; Zavorka, L.

    Experiments with the natural uranium target assembly "QUINTA" exposed to 4 and 8 GeV deuteron beams of the Nuclotron accelerator at the Joint Institute for Nuclear Research (Dubna) are analyzed. The reaction rates of 27Al(n,y1)24Na, 27Al(n,y2)22Na and 27Al(n,y3)7Be reactions with effective threshold energies of 5, 27, and 119 MeV were measured at both 4 GeV and 8 GeV deuteron beam energies. The average neutron fluxes between the effective threshold energies and the effective ends of the neutron spectra (which are 800 or 1000 MeV for 4 or 8 GeV deuterons) were determined. The evidence for the intensity shift of the neutron spectra to higher neutron energies with the increase of the deuteron energy from 4 GeV to 8 GeV was found from the ratios of the average neutron fluxes. The reaction rates and the average neutron fluxes were calculated with the MCNPX 2.7 code.

  5. Neutron production from 158 GeV/c per nucleon lead ions on thin copper and lead targets in the angular range 30-135 degree

    CERN Document Server

    Silari, Marco; Birattari, C; Foglio-Para, A; Gini, L; Mitaroff, Angela; Ulrici, L

    2002-01-01

    The neutron emission from 5, 10 and 20 mm thick lead and 10 and 20 mm thick copper targets bombarded by a lead ion beam with momentum of 158 GeV/c per nucleon were measured at the CERN Super Proton Synchrotron. The neutron yield and spectral fluence per incident ion on target were measured with an extended range Bonner sphere spectrometer in the angular range 30-135 degree with respect to beam direction. Monte Carlo simulations with the FLUKA code were performed to establish a guess spectrum for the unfolding of the experimental data. The results have shown that, lacking Monte Carlo radiation transport codes dealing with ions with masses larger than 1 amu, a reasonable prediction can be carried out by scaling the result of a Monte Carlo calculation for protons by the projectile mass number to the power of 0.85-0.95 for a lead target and 0.88-1.03 for a copper target.

  6. Evaluation of target photon dose mixed in mono-energetic neutron fields using {sup 7}Li(p,n){sup 7}Be reaction

    Energy Technology Data Exchange (ETDEWEB)

    Tanimura, Y., E-mail: tanimura.yoshihiko@jaea.go.j [Department of Radiation Protection, Nuclear Science and Research Institute, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai-mura, Ibaraki 319-1195 (Japan); Tsutsumi, M.; Saegusa, J.; Shikaze, Y.; Yoshizawa, M. [Department of Radiation Protection, Nuclear Science and Research Institute, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai-mura, Ibaraki 319-1195 (Japan)

    2010-12-15

    Target photons mixed in the 144, 250 and 565 keV mono-energetic neutron calibration fields were measured using a cylindrical NaI(Tl) detector with 7.62 cm both in diameter and in length. The ambient dose equivalent H*(10) of the photons was evaluated by applying the 'G(E) function' to the measured pulse height spectrum. Neutrons induce photons by nuclear reactions in the NaI(Tl) detector and affect the pulse height spectrum. In order to eliminate the influence of these neutron events, the time-of-flight technique was applied with operating the accelerator in the pulse mode. The ratios by the ambient dose equivalent H*(10) of the photons to the 144, 250 and 565 keV neutrons were evaluated to be 3.3%, 4.7% and 0.9%, respectively. Although high energy photons ranging from 6 to 7 MeV are emitted by the {sup 19}F(p,{alpha}{gamma}){sup 16}O reactions, the dose of the target photons is low enough to calibrate neutron dosemeters except for ones with high sensitivity to the photons.

  7. Neutron-rich isotope production using a uranium carbide - carbon nanotubes SPES target prototype

    Science.gov (United States)

    Corradetti, S.; Biasetto, L.; Manzolaro, M.; Scarpa, D.; Carturan, S.; Andrighetto, A.; Prete, G.; Vasquez, J.; Zanonato, P.; Colombo, P.; Jost, C. U.; Stracener, D. W.

    2013-05-01

    The SPES (Selective Production of Exotic Species) project, under development at the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro (INFN-LNL), is a new-generation Isotope Separation On-Line (ISOL) facility for the production of radioactive ion beams by means of the proton-induced fission of uranium. In the framework of the research on the SPES target, seven uranium carbide discs, obtained by reacting uranium oxide with graphite and carbon nanotubes, were irradiated with protons at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL). In the following, the yields of several fission products obtained during the experiment are presented and discussed. The experimental results are then compared to those obtained using a standard uranium carbide target. The reported data highlights the capability of the new type of SPES target to produce and release isotopes of interest for the nuclear physics community.

  8. Parallel computation safety analysis irradiation targets fission product molybdenum in neutronic aspect using the successive over-relaxation algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Susmikanti, Mike, E-mail: mike@batan.go.id [Center for Development of Nuclear Informatics, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia); Dewayatna, Winter, E-mail: winter@batan.go.id [Center for Nuclear Fuel Technology, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia); Sulistyo, Yos, E-mail: soj@batan.go.id [Center for Nuclear Equipment and Engineering, National Nuclear Energy Agency, PUSPIPTEK, Tangerang (Indonesia)

    2014-09-30

    One of the research activities in support of commercial radioisotope production program is a safety research on target FPM (Fission Product Molybdenum) irradiation. FPM targets form a tube made of stainless steel which contains nuclear-grade high-enrichment uranium. The FPM irradiation tube is intended to obtain fission products. Fission materials such as Mo{sup 99} used widely the form of kits in the medical world. The neutronics problem is solved using first-order perturbation theory derived from the diffusion equation for four groups. In contrast, Mo isotopes have longer half-lives, about 3 days (66 hours), so the delivery of radioisotopes to consumer centers and storage is possible though still limited. The production of this isotope potentially gives significant economic value. The criticality and flux in multigroup diffusion model was calculated for various irradiation positions and uranium contents. This model involves complex computation, with large and sparse matrix system. Several parallel algorithms have been developed for the sparse and large matrix solution. In this paper, a successive over-relaxation (SOR) algorithm was implemented for the calculation of reactivity coefficients which can be done in parallel. Previous works performed reactivity calculations serially with Gauss-Seidel iteratives. The parallel method can be used to solve multigroup diffusion equation system and calculate the criticality and reactivity coefficients. In this research a computer code was developed to exploit parallel processing to perform reactivity calculations which were to be used in safety analysis. The parallel processing in the multicore computer system allows the calculation to be performed more quickly. This code was applied for the safety limits calculation of irradiated FPM targets containing highly enriched uranium. The results of calculations neutron show that for uranium contents of 1.7676 g and 6.1866 g (× 10{sup 6} cm{sup −1}) in a tube, their delta

  9. Isotopic distributions of the sup 1 sup 8 N fragmentation products in coincidence with neutrons on targets sup 1 sup 9 sup 7 Au and sup 9 Be

    CERN Document Server

    Li Xiang Qing; Ye Yan Lin; Hua Hui; Chen Tao; Li Zhi Huan; Ge Yuch Eng; Wang Quan Jin; Wu He Yu; Jin Ge; Duan Li Min; Xiao Zhi Gang; Wang Hong Wei; Li Zhu Yu; Wang Su Fang

    2002-01-01

    The authors present the experimental isotopic distributions of the sup 1 sup 8 N projectile fragmentation products Li, Be, B and C in coincidence with neutrons, as well as the inclusive ones on sup 1 sup 9 sup 7 Au and sup 9 Be targets. In the framework of the abrasion-ablation model, these distributions are calculated for various nucleon density distributions of the projectile. The comparison with experimental isotopic distributions of the projectile-like fragments in coincidence with neutrons shows that the information on the nucleon density distribution of the sup 1 sup 8 N projectile can be extracted

  10. THERMAL NEUTRON FLUX MAPPING ON A TARGET CAPSULE AT RABBIT FACILITY OF RSG-GAS REACTOR FOR USE IN k0-INAA

    Directory of Open Access Journals (Sweden)

    Sutisna Sutisna

    2015-03-01

    Full Text Available Instrumental neutron activation analysis based on the k0 method (k0-INAA requires the availability of the accurate reactor parameter data, in particular a thermal neutron flux that interact with a targets inside the target capsule. This research aims to determine and map the thermal neutron flux inside the capsule and irradiation channels used for the elemental quantification using the k0-AANI. Mapping of the thermal neutron flux (фth on two type of irradiation capsule have been done for RS01 and RS02 facilities of RSG-GAS reactor. Thermal neutron flux determined using Al-0,1%Au alloy through 197Au(n,g 198Au nuclear reaction, while the flux mapping done using statistics R. Thermal neutron flux are calculated using k0-IAEA software provided by IAEA. The results showed the average thermal neutron flux is (5.6±0.3×10+13 n.cm-2.s-1; (5.6±0.4×10+13 n.cm-2.s-1; (5.2±0.4×10+13 n.cm-2.s-1 and (5.3±0.4×10+13 n.cm-2.s-1 for Polyethylene capsule of 1st , 2nd, 3rd and 4th layer respectively. In the case of Aluminum capsule, the thermal neutron flux was lower compared to that on Polyethylene capsule. There were (3.0±0.2×10+13 n.cm-2.s-1; (2.8±0.1×10+13 n.cm-2.s-1; (3.2±0.3×10+13 n.cm-2.s-1 for 1st, 2nd and 3rd layers respectively. For each layer in the capsule, the thermal neutron flux is not uniform and it was no degradation flux in the axial direction, both for polyethylene and aluminum capsules. Contour map of eight layer on polyethylene capsule and six layers on aluminum capsule for RS01 and RS02 irradiation channels had a similar pattern with a small diversity for all type of the irradiation capsule. Keywords: thermal neutron, flux, capsule, NAA   Analisis aktivasi neutron instrumental berbasis metode k0 (k0-AANI memerlukan ketersediaan data parameter reaktor yang akurat, khususnya data fluks neutron termal yang berinteraksi dengan inti sasaran di dalam kapsul target. Penelitian ini bertujuan menentukan dan memetakan fluks neutron termal

  11. Thick-target neutron, gamma-ray, and radionuclide production for protons below 12 MeV on nickel and carbon beam-stops

    Energy Technology Data Exchange (ETDEWEB)

    Chadwick, M.B.; Young, P.G.; Wilson, W.B.

    1998-03-01

    Nuclear model calculations using the GNASH code are described for protons below 12 MeV incident on nickel and carbon isotopes, for beam stop design in the Los Alamos Accelerator Production of Tritium Low Energy Demonstration Accelerator (LEDA) project. The GNASH calculations apply Hauser-Feshbach and preequilibrium reaction theories and can make use of pre-calculated direct reaction cross sections to low-lying residual nucleus states. From calculated thin target cross sections, thick target 6.7 MeV and 12 MeV proton-induced production of neutrons, gamma rays, and radionuclides are determined. Emission spectra of the secondary neutrons and gamma rays are also determined. The model calculations are validated through comparisons with experimental thin- and thick-target measurements. The results of this work are being utilized as source terms in MCNP analyses for LEDA.

  12. Summary of Mercury Compatibility Issues for the Spallation Neutron Source Target Containment and Ancillary Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, SJ

    2003-04-08

    The purpose of this document is to summarize the primary results of the Hg compatibility research in support of the SNS target. In the absence of possible synergisms resulting from beam/irradiation effects, wetting of 316L/316LN stainless steel under SNS conditions by the Hg target is expected to be very limited. As a result, significant interactions such as dissolution, mass transfer, and embrittlement affecting general compatibility are not anticipated. A wide range of experiments on 316L/316LN stainless steel, including thermal convection and pumped loops, confirmed low corrosion/penetration rates in Hg up to 305 C and little or no wetting or mass transfer below about 250 C. A variety of standard mechanical tests comparing behavior of 316L in air and Hg revealed limited wetting and no degradation of mechanical properties such as reduced elongation or development of brittle fracture features. Preliminary fatigue tests indicated a negative effect (reduced cycles to failure and intergranular cracking) at very high loads for 316LN, but little or no effect at more modest loading. Annealed 316LN was found to be somewhat susceptible to cavitation-erosion damage, but significant improvement was realized with a kolsterizing surface treatment or coldworking the material. Within the scope of these test conditions, no compatibility-limited operations were identified for type 316L/316LN stainless steel (and variations thereof) as the Hg target containment material. More limited compatibility data on other materials are also reported.

  13. High power accelerator-based boron neutron capture with a liquid lithium target and new applications to treatment of infectious diseases

    Energy Technology Data Exchange (ETDEWEB)

    Halfon, S. [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)], E-mail: halfon@phys.huji.ac.il; Paul, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Steinberg, D. [Biofilm Laboratory, Institute of Dental Sciences, Faculty of Dentistry, Hebrew University-Hadassah (Israel); Nagler, A.; Arenshtam, A.; Kijel, D. [Soreq NRC, Yavne 81800 (Israel); Polacheck, I. [Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center (Israel); Srebnik, M. [Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Hebrew University, Jerusalem 91120 (Israel)

    2009-07-15

    A new conceptual design for an accelerator-based boron neutron capture therapy (ABNCT) facility based on the high-current low-energy proton beam driven by the linear accelerator at SARAF (Soreq Applied Research Accelerator Facility) incident on a windowless forced-flow liquid-lithium target, is described. The liquid-lithium target, currently in construction at Soreq NRC, will produce a neutron field suitable for the BNCT treatment of deep-seated tumor tissues, through the reaction {sup 7}Li(p,n){sup 7}Be. The liquid-lithium target is designed to overcome the major problem of solid lithium targets, namely to sustain and dissipate the power deposited by the high-intensity proton beam. Together with diseases conventionally targeted by BNCT, we propose to study the application of our setup to a novel approach in treatment of diseases associated with bacterial infections and biofilms, e.g. inflammations on implants and prosthetic devices, cystic fibrosis, infectious kidney stones. Feasibility experiments evaluating the boron neutron capture effectiveness on bacteria annihilation are taking place at the Soreq nuclear reactor.

  14. High power accelerator-based boron neutron capture with a liquid lithium target and new applications to treatment of infectious diseases.

    Science.gov (United States)

    Halfon, S; Paul, M; Steinberg, D; Nagler, A; Arenshtam, A; Kijel, D; Polacheck, I; Srebnik, M

    2009-07-01

    A new conceptual design for an accelerator-based boron neutron capture therapy (ABNCT) facility based on the high-current low-energy proton beam driven by the linear accelerator at SARAF (Soreq Applied Research Accelerator Facility) incident on a windowless forced-flow liquid-lithium target, is described. The liquid-lithium target, currently in construction at Soreq NRC, will produce a neutron field suitable for the BNCT treatment of deep-seated tumor tissues, through the reaction (7)Li(p,n)(7)Be. The liquid-lithium target is designed to overcome the major problem of solid lithium targets, namely to sustain and dissipate the power deposited by the high-intensity proton beam. Together with diseases conventionally targeted by BNCT, we propose to study the application of our setup to a novel approach in treatment of diseases associated with bacterial infections and biofilms, e.g. inflammations on implants and prosthetic devices, cystic fibrosis, infectious kidney stones. Feasibility experiments evaluating the boron neutron capture effectiveness on bacteria annihilation are taking place at the Soreq nuclear reactor.

  15. Spectrometry behind concrete shielding for neutrons produced by 400 MeV/u {sup 12}C ions impinging on a thick graphite target

    Energy Technology Data Exchange (ETDEWEB)

    Fehrenbacher, G.; Iwase, H.; Radon, T.; Schardt, D.; Wiegel, B.; Schuhmacher, H.; Wittstock, J. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2004-03-01

    Neutron spectra were measured at the GSI heavy ion accelerator using the Bonner sphere spectrometer NEMUS. The irradiation experiments were carried out at Cave A, an experimental area at the GSI heavy ion synchrotron SIS. A 400 MeV/u carbon ion beam impinging on a thick graphite target was used as neutron source. Spectral distributions were determined by unfolding the measured readings using the unfolding code MAXED for four positions outside the shielding and for four positions in the entry maze of Cave A. First results are presented for two positions from Monte Carlo simulations carried out with a newer version of FLUKA considering both the particle production in nucleus-nucleus collisions and the transportation of particles through the shielding. Measured and calculated neutron spectra are compared for these positions. (orig.)

  16. Determination of neutron spectra formed by 40-MeV deuteron bombardment of a lithium target with multi-foil activation technique

    CERN Document Server

    Maekawa, F; Wada, M; Wilson, P P H; Ikeda, Y

    2000-01-01

    Neutron flux spectra at an irradiation field produced by a 40-MeV deuteron bombardment on a thick lithium-target at Forschungszentrum Karlsruhe, Germany, have been determined by the multi-foil activation technique. Twenty-seven dosimetry reactions having a wide energy range of threshold energies up to 38 MeV were employed as detectors for the neutron flux spectra extending to 55 MeV. The spectra were adjusted with the SAND-II code with the experimental reaction rates based on an iterative method. The adjusted spectra validated quantitatively the Monte Carlo deuteron-lithium (d-Li) neutron source model code (M sup C DeLi) which was used to calculate initial guess spectra and also has been used for IFMIF nuclear designs. Accuracy of the adjusted spectra was approx 10% that was suitable for successive integral tests of activation cross section data.

  17. Correlation between simulations and cavitation-induced erosion damage in Spallation Neutron Source target modules after operation

    Energy Technology Data Exchange (ETDEWEB)

    Riemer, Bernie [ORNL; McClintock, David A [ORNL; Kaminskas, Saulius [ORNL; Abdou, Ashraf A [ORNL

    2014-01-01

    An explicit finite element (FE) technique developed for estimating dynamic strain in the Spallation Neutron Source (SNS) mercury target module vessel is now providing insight into cavitation damage patterns observed in used targets. The technique uses an empirically developed material model for the mercury that describes liquid-like volumetric stiffness combined with a tensile pressure cut-off limit that approximates cavitation. The longest period each point in the mercury is at the tensile cut-off threshold is denoted its saturation time. Now, the pattern of saturation time can be obtained from these simulations and is being positively correlated with observed damage patterns and is interpreted as a qualitative measure of damage potential. Saturation time has been advocated by collaborators at J-Parc as a factor in predicting bubble nuclei growth and collapse intensity. The larger the ratio of maximum bubble size to nucleus, the greater the bubble collapse intensity to be expected; longer saturation times result in greater ratios. With the recent development of a user subroutine for the FE solver saturation time is now provided over the entire mercury domain. Its pattern agrees with spots of damage seen above and below the beam axis on the SNS inner vessel beam window and elsewhere. The other simulation result being compared to observed damage patterns is mercury velocity at the wall. Related R&D has provided evidence for the damage mitigation that higher wall velocity provides. In comparison to observations in SNS targets, inverse correlation of high velocity to damage is seen. In effect, it is the combination of the patterns of saturation time and low velocity that seems to match actual damage patterns.

  18. SU-E-T-495: Influence of Reduced Target-To-Nozzle Distance On Secondary Neutron Dose Equivalent in Proton and Carbon Ion Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Y; Shahnazi, K; Wang, W; Moyers, M; Deng, Y; Huang, Z; Liu, X [Shanghai Proton and Heavy Ion Center, Shanghai (China)

    2015-06-15

    Purpose: Ion beams have an unavoidable lateral spread due to nuclear interactions interacting with the air and monitoring systems. To minimize this spread, the distance between the nozzle and the patient should be kept as small as possible.The purpose of this work was to determine the impact of the target-to-nozzle distance reduction on the secondary neutron dose equivalent in proton and carbon ion radiotherapy. Methods: In this study, abdominal and head phantoms were scanned with our CT scanner. Cubical targets with side lengths of 3 cm to 10 cm and 1 cm to 5 cm were drawn in the abdominal and head phantoms respectively. Two intensity-modulated plans were made for each phantom and ion. The first of these plans placed the target at the isocenter while the other shifted the phantom 30 cm towards the nozzle. The plans at both phantom locations were optimized to provide identical dose coverage to the PTVs.Secondary neutron dose equivalent at 50 cm lateral to the center of target. Results: The neutron dose equivalent was higher for the larger field size from 0.25µSv per Gy (RBE) to 72µSv per Gy (RBE). The neutron dose equivalent was smaller when the phantom was placed at the upstream target location versus at the isocenter location by 8.9% to 10.4% and 11.0% to 22.1% for proton plans of the abdominal and head phantoms respectively. Differences for carbon plans with different target-to-nozzle locations were less than 3% for both phantoms. Conclusion: A reduction of target-to-nozzle distance can lead to benefits for proton radiotherapy. In this study, a reduction of secondary neutron dose equivalent was found for proton plans with a smaller target-to-nozzle distance. A greater impact was found for a head phantom with a smaller field size; however, a reduction of the target-to-nozzle distance had little effect for carbon therapy.

  19. Comments on the possibility of cavitation in liquid metal targets for pulsed spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter J.M. [Argonne National Lab., IL (United States)

    1996-06-01

    When short pulses of protons strike the volume of a liquid target, the rapid heating produces a pressurized region which relaxes as the pressure wave propagates outward. Skala and Bauer have modeled the effects of the pressure wave impinging on the container walls of a liquid mercury target under ESS conditions. They find that high pressures and high wall stresses result if the medium is uniform, nearly incompressible liquid. The pressure and the stresses are much reduced if the liquid contains bubbles of helium, due to their high compressibility. However, according to the calculation, the pressure still reaches an atmosphere or so at the surface, which reflects the compressive wave as a rarefaction wave of the same magnitude. Even such modest underpressures can lead to the growth of bubbles (cavitation) at or near the surface, which can collapse violently and erode the container surface. It is necessary to avoid this. Leighton provides a wide ranging discussion of pressure waves in bubbly media, which may provide insights into the nature and control of cavitation phenomena. The paper surveys some of the relevant information from that source.

  20. 用MCNPX计算ADS金属靶散裂中子产额及散裂源中子效率%A MCNPX Caculation of the spallation neutron yields from various metal targets and the neutron source efficiency in ADS

    Institute of Scientific and Technical Information of China (English)

    景桂芬; 时磊

    2011-01-01

    为了分析加速器驱动系统(ADS)中质子束能量对金属靶散裂产生的中子产额及靶内中子能谱、靶表面的泄漏谱的影响,利用MCNPX对ADS的重金属铅靶、钨靶在不同能量的质子束轰击下的中子产额、中子能谱及靶表面的中子泄漏谱进行了模拟计算,与国际上其他研究机构的模拟结果进行了比较,结果相近.并对铅靶、钨靶的中子产额及泄漏谱进行比较,模拟结果是钨靶的中子产额较铅靶的中子产额大但中子泄漏谱计数较铅的小.结合MCNP5还对一个次临界基准体系中散裂源中子相对于裂变中子的效率进行了计算.%In order to analyze the effect of the proton energy on the number of neutrons produced per source proton and the neutron yield spectra and values of neutron leakage distributions per proton over the cylindrical metal target surface in Accelerator Driven System (ADS),MCNPX are used to calculate them under different proton beam energy,and the results are compared with the results of the international organization institutions.The number of neutrons produced per source proton of tungsten target is larger but the tally of neutron leakage is smaller than lead target.Combining the MCNPX with MCNP5,the efficiency of the spallation neutions relative to fission neutrons for a subcritical benchmark system was calculated.

  1. Simulation study of neutron production in thick beryllium targets by 35 MeV and 50.5 MeV proton beams

    Science.gov (United States)

    Shin, Jae Won; Park, Tae-Sun

    2017-09-01

    A data-driven nuclear model dedicated to an accurate description of neutron productions in beryllium targets bombarded by proton beams is developed as a custom development that can be used as an add-on to GEANT4 code. The developed model, G4Data(Endf7.1), takes as inputs the total and differential cross section data of ENDF/B-VII.1 for not only the charge-exchange 9Be(p,n)9B reaction which produces discrete neutrons but also the nuclear reactions relevant for the production of continuum neutrons such as 9Be(p,pn)8Be and 9Be(p,n α) 5Li . In our benchmarking simulations for two experiments with 35 MeV and 50.5 MeV proton beams impinged on 1.16 and 1.05 cm thick beryllium targets, respectively, we find that the G4Data(Endf7.1) model can reproduce both the total amounts and the spectral shapes of the measured neutron yield data in a satisfactory manner, while all the considered hadronic models of GEANT4 cannot.

  2. Development and testing of a deuterium gas target assembly for neutron production via the H-2(d,n)He-3 reaction at a low-energy accelerator facility

    Energy Technology Data Exchange (ETDEWEB)

    Feautrier, D.; Smith, D.L.

    1992-03-01

    This report describes the development and testing of a deuterium gas target intended for use at a low-energy accelerator facility to produce neutrons for basic research and various nuclear applications. The principle source reaction is H-2(d,n)He-3. It produces a nearly mono-energetic group of neutrons. However, a lower-energy continuum neutron spectrum is produced by the H-2(d;n,p)H-2 reaction and also by deuterons which strike various components in the target assembly. The present target is designed to achieve the following objectives: (1) minimize unwanted background neutron production from the target assembly, (2) provide a relatively low level of residual long-term activity within the target components, (3) have the capacity to dissipate up to 150 watts of beam power with good target longevity, and (4) possess a relatively modest target mass in order to minimize neutron scattering from the target components. The basic physical principles that have to be considered in designing an accelerator target are discussed and the major engineering features of this particular target design are outlined. The results of initial performance tests on this target are documented and some conclusions concerning the viability of the target design are presented.

  3. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  4. Characterization of uranium carbide target materials to produce neutron-rich radioactive beams

    Energy Technology Data Exchange (ETDEWEB)

    Tusseau-Nenez, Sandrine; Roussière, Brigitte; Barré-Boscher, Nicole [Institut de Physique Nucléaire (UMR8608) CNRS/IN2P3 – Université Paris Sud, 91406 Orsay Cedex (France); Gottberg, Alexander [CERN, CH-1211 Genève 23 (Switzerland); Corradetti, Stefano; Andrighetto, Alberto [INFN Laboratori Nazionali di Legnaro, Viale dell’Universit‘a 2, 35020 Legnaro (PD) (Italy); Cheikh Mhamed, Maher; Essabaa, Saïd [Institut de Physique Nucléaire (UMR8608) CNRS/IN2P3 – Université Paris Sud, 91406 Orsay Cedex (France); Franberg-Delahaye, Hanna; Grinyer, Joanna [Grand Accélérateur National d’Ions Lourds (GANIL), CEA/DSM-CNRS/IN2P3, Bd Henri Becquerel, 14076 Caen (France); Joanny, Loïc [Institut des Sciences Chimiques de Rennes (UMR 6226) CNRS – Université de Rennes 1, Campus de Beaulieu, 35042 RENNES Cedex (France); Lau, Christophe [Institut de Physique Nucléaire (UMR8608) CNRS/IN2P3 – Université Paris Sud, 91406 Orsay Cedex (France); Le Lannic, Joseph [Institut des Sciences Chimiques de Rennes (UMR 6226) CNRS – Université de Rennes 1, Campus de Beaulieu, 35042 RENNES Cedex (France); Raynaud, Marc; Saïd, Abdelhakim [Institut de Physique Nucléaire (UMR8608) CNRS/IN2P3 – Université Paris Sud, 91406 Orsay Cedex (France); Stora, Thierry [CERN, CH-1211 Genève 23 (Switzerland); and others

    2016-03-01

    In the framework of a R&D program aiming to develop uranium carbide (UC{sub x}) targets for radioactive nuclear beams, the Institut de Physique Nucléaire d’Orsay (IPNO) has developed an experimental setup to characterize the release of various fission fragments from UC{sub x} samples at high temperature. The results obtained in a previous study have demonstrated the feasibility of the method and started to correlate the structural properties of the samples and their behavior in terms of nuclear reaction product release. In the present study, seven UC{sub x} samples have been systematically characterized in order to better understand the correlation between their physicochemical characteristics and release properties. Two very different samples, the first one composed of dense UC and the second one of highly porous UC{sub x} made of multi-wall carbon nanotubes, were provided by the ActILab (ENSAR) collaboration. The others were synthesized at IPNO. The systems for irradiation and heating necessary for the release studies have been improved with respect to those used in previous studies. The results show that the open porosity is hardly the limiting factor for the fission product release. The homogeneity of the microstructure and the pore size distribution contributes significantly to the increase of the release. The use of carbon nanotubes in place of traditional micrometric graphite particles appears to be promising, even if the homogeneity of the microstructure can still be enhanced.

  5. Neutron-emission measurements at a white neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory

    2010-01-01

    Data on the spectrum of neutrons emittcd from neutron-induced reactions are important in basic nuclear physics and in applications. Our program studies neutron emission from inelastic scattering as well as fission neutron spectra. A ''white'' neutron source (continuous in energy) allows measurements over a wide range of neutron energies all in one experiment. We use the tast neutron source at the Los Alamos Neutron Science Center for incident neutron energies from 0.5 MeV to 200 MeV These experiments are based on double time-of-flight techniques to determine the energies of the incident and emitted neutrons. For the fission neutron measurements, parallel-plate ionization or avalanche detectors identify fission in actinide samples and give the required fast timing pulse. For inelastic scattering, gamma-ray detectors provide the timing and energy spectroscopy. A large neutron-detector array detects the emitted neutrons. Time-of-flight techniques are used to measure the energies of both the incident and emitted neutrons. Design considerations for the array include neutron-gamma discrimination, neutron energy resolution, angular coverage, segmentation, detector efficiency calibration and data acquisition. We have made preliminary measurements of the fission neutron spectra from {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. Neutron emission spectra from inelastic scattering on iron and nickel have also been investigated. The results obtained will be compared with evaluated data.

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

    Science.gov (United States)

    Khaial, Anas M.

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

  7. Estimations and integral measurements for the spectral yield of neutrons from thick beryllium target bombarded with 16 MeV protons

    CERN Document Server

    Fenyvesi, A

    2015-01-01

    Spectral yield of p+Be neutrons emitted by thick (stopping) beryllium target bombarded by 16 MeV protons was estimated via extrapolation of literature data. The spectrum was validated via multi-foil activation method and irradiation of 2N2222 transistors. The hardness parameter (NIEL scaling factor) for displacement damage in bulk silicon was calculated and measured and kappa = 1.26 +- 0.1 was obtained.

  8. Improvement of Radiological Teaching - Effects of Focusing of Learning Targets and Increased Consideration of Learning Theory Knowledge.

    Science.gov (United States)

    Wirth, Stefan; William, York-Alexander; Paolini, Marco; Wirth, Kathrin; Maxien, Daniel; Reiser, Maximilian; Fischer, Martin R

    2017-09-20

    examination questions from past state examinations.. · This supports further steps towards excellent radiological teaching.. Citation Format · Wirth S, William Y, Paolini M et al. Improvement of Radiological Teaching - Effects of Focusing of Learning Targets and Increased Consideration of Learning Theory Knowledge. Fortschr Röntgenstr 2017; DOI: 10.1055/s-0043-119037. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Conversion of Molybdenum-99 production process to low enriched uranium: Neutronic and thermal hydraulic analyses of HEU and LEU target plates for irradiation in Pakistan Research Reactor-1

    Science.gov (United States)

    Mushtaq, Ahmad; Iqbal, Masood; Bokhari, Ishtiaq Hussain; Mahmood, Tayyab; Muhammad, Atta

    2012-09-01

    Technetium-99m, the daughter product of Molybdenum-99 is the most widely needed radionuclide for diagnostic studies in Pakistan. Molybdenum-99 Production Facility has been established at PINSTECH. Highly enriched uranium (93% 235U) U/Al alloy targets have been irradiated in Pakistan Research Reactor-1 (PARR-1) for the generation of fission Mo-99, while basic dissolution technique is used for separation of Mo-99 from target matrix activity. In line with the international objective of minimizing and eventually eliminating the use of HEU in civil commerce, national and international efforts have been underway to shift the production of medical isotopes from HEU to LEU (LEU; uranium is needed. LEU aluminum uranium dispersion target has been developed, which may replace existing HEU aluminum/uranium alloy targets for production of 99Mo using basic dissolution technique. Neutronic and thermal hydraulic calculations were performed for safe irradiation of targets in the core of PARR-1.

  10. T-violation in neutron optics

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Y. [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    Experimental method to detect a T-odd correlation term in neutron propagation through a nuclear target is discussed. The correlation term is between the neutron spin, neutron momentum and nuclear spin. (author)

  11. Systematic neutron guide misalignment for an accelerator-driven spallation neutron source

    Science.gov (United States)

    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.

  12. Analytical calculations and Monte-Carlo simulations of a high-resolution backscattering spectrometer for the long wavelength target station at the Spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Bordallo, H.N. E-mail: bordallo@hmi.de; Herwig, K.W.; Zsigmond, G

    2002-09-21

    Using the Monte-Carlo simulation programs McStas and VITESS, we present the design principles of the proposed high-resolution inverse geometry spectrometer on the Spallation neutron source (SNS) - long wavelength target station (LWTS). LWTS will enable the combination of large energy and momentum transfer ranges with energy resolution. Indeed the resolution of this spectrometer lie between that routinely achieved by spin echo techniques and the design goal of the high-power target station (HPTS) backscattering spectrometer. This niche of energy resolution is interesting for the study of slow motions of large objects and we are led to the domain of large molecules - polymers and biological molecules.

  13. Analytical calculations and Monte-Carlo simulations of a high-resolution backscattering spectrometer for the long wavelength target station at the Spallation neutron source

    CERN Document Server

    Bordallo, H N; Zsigmond, G

    2002-01-01

    Using the Monte-Carlo simulation programs McStas and VITESS, we present the design principles of the proposed high-resolution inverse geometry spectrometer on the Spallation neutron source (SNS) - long wavelength target station (LWTS). LWTS will enable the combination of large energy and momentum transfer ranges with energy resolution. Indeed the resolution of this spectrometer lie between that routinely achieved by spin echo techniques and the design goal of the high-power target station (HPTS) backscattering spectrometer. This niche of energy resolution is interesting for the study of slow motions of large objects and we are led to the domain of large molecules - polymers and biological molecules.

  14. Investigation of Fast Neutron Production by 100 to 250~GeV Muon Interactions on Thin Targets

    CERN Multimedia

    2002-01-01

    % NA55 \\\\ \\\\ The production of fast (1~MeV~-~1~GeV) neutrons in high energy muon-nucleon interactions is poorly understood. Yet it is essential to the understanding of the background in many underground neutrino experiments and, in particular, may hold relevance for the atmospheric neutrino anomaly. We propose an experiment to investigate fast neutron production using the M2 muon beam at the CERN SPS.

  15. Attenuation curves in concrete of neutrons from 1 GeV/u C and U ions on a Fe target for the shielding design of RIB in-flight facilities

    CERN Document Server

    Agosteo, S; Silari, M

    2004-01-01

    Experimental data on neutron emission from the interaction of heavy ion beams with matter are far less abundant than data on neutron production from protons. The aim of the present work is to extend the available computational shielding data to high-energy neutrons produced by heavy ion beams (uranium and carbon) of 1 GeV/u slowed down in a thick iron target. Source terms and attenuation lengths for neutron attenuation in a concrete shield were calculated starting from experimental neutron energy distributions measured at GSI in the angular range from 0 degree to 90 degree . A comparison is also made with previous calculations performed for different ions and energies and with earlier estimates made at GSI for neon beams with 0.8 and 2 GeV/u energy stopped in thick iron, lead and uranium targets.

  16. A Measurement of the neutron electric form factor at very large momentum transfer using polaried electrions scattering from a polarized helium-3 target

    Energy Technology Data Exchange (ETDEWEB)

    Kelleher, Aidan [College of William and Mary, Williamsburg, VA (United States)

    2010-02-01

    Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. Of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q2 and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized 3 He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Polarized electrons were scattered off this target, and both the scattered electron and neutron were detected. Gn E was measured to be 0.0242 ± 0.0020(stat) ± 0.0061(sys) and 0.0247 ± 0.0029(stat) ± 0.0031(sys) at Q2 = 1.7 and 2.5 GeV2 , respectively.

  17. EURISOL-DS multi-MW target unit: Neutronics performance and shielding assessment, dose rate and material activation calculations for the MAFF configuration

    CERN Document Server

    Romanets, Y; Kadi, Y; Luis, R; Goncalves, I F; Tecchio, L; Kharoua, C; Vaz, P; Ene, D; David, J C; Rocca, R; Negoita, F

    2010-01-01

    One of the objectives of the EURISOL (EURopean Isotope Separation On-Line Radioactive Ion Beam) Design Study consisted of providing a safe and reliable facility layout and design for the following operational parameters and characteristics: (a) a 4 MW proton beam of 1 GeV energy impinging on a mercury target (the converter); (b) high neutron fluxes (similar to 3 x 10(16) neutrons/s) generated by spallation reactions of the protons impinging in the converter and (c) fission rate on fissile U-235 targets in excess of 10(15) fissions/s. In this work, the state-of-the-art Monte Carlo codes MCNPX (Pelowitz, 2005) and FLUKA (Vlachoudis, 2009; Ferrari et al., 2008) were used to characterize the neutronics performance and to perform the shielding assessment (Herrera-Martinez and Kadi, 2006; Cornell, 2003) of the EURISOLTarget Unit and to provide estimations of dose rate and activation of different components, in view of the radiation safety assessment of the facility. Dosimetry and activation calculations were perfor...

  18. Assessment of Laser-Driven Pulsed Neutron Sources for Poolside Neutron-based Advanced NDE – A Pathway to LANSCE-like Characterization at INL

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Markus [Technische Univ. Darmstadt (Germany); Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bourke, Mark Andrew M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fernandez, Juan Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mocko, Michael Jeffrey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Glenzer, Siegfried [Stanford Univ., CA (United States); Leemans, Wim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Siders, Craig [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Haefner, Constantin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-04-19

    A variety of opportunities for characterization of fresh nuclear fuels using thermal (~25meV) and epithermal (~10eV) neutrons have been documented at Los Alamos National Laboratory. They include spatially resolved non-destructive characterization of features, isotopic enrichment, chemical heterogeneity and stoichiometry. The LANSCE spallation neutron source is well suited in neutron fluence and temporal characteristics for studies of fuels. However, recent advances in high power short pulse lasers suggest that compact neutron sources might, over the next decade, become viable at a price point that would permit their consideration for poolside characterization on site at irradiation facilities. In a laser-driven neutron source the laser is used to accelerate deuterium ions into a beryllium target where neutrons are produced. At this time, the technology is new and their total neutron production is approximately four orders of magnitude less than a facility like LANSCE. However, recent measurements on a sub-optimized system demonstrated >1010 neutrons in sub-nanosecond pulses in predominantly forward direction. The compactness of the target system compared to a spallation target may allow exchanging the target during a measurement to e.g. characterize a highly radioactive sample with thermal, epithermal, and fast neutrons as well as hard X-rays, thus avoiding sample handling. At this time several groups are working on laser-driven neutron production and are advancing concepts for lasers, laser targets, and optimized neutron target/moderator systems. Advances in performance sufficient to enable poolside fuels characterization with LANSCE-like fluence on sample within a decade may be possible. This report describes the underlying physics and state-of-the-art of the laser-driven neutron production process from the perspective of the DOE/NE mission. It also discusses the development and understanding that will be necessary to provide customized capability for

  19. Conceptual design for a neutron imaging system for thick target analysis operating in the 10-15 MeV energy range

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, F.; Hall, J.; Logan, C.

    1996-09-11

    Fast neutron imaging offers the potential to be a powerful non- destructive inspection tool for evaluating the integrity of thick sealed targets. This is particularly true in cases where one is interested in detecting voids, cracks or other defects in low-Z materials (e.g. plastics, ceramics, salts, etc.) which are shielded by thick, high-Z parts. In this paper we present the conceptual design for a neutron imaging system for use in the 10 - 15 MeV energy range and discuss potential applications in the area of nuclear stockpile steward- ship. The background of this project, currently under development at LLNL, will be outlined and computer simulations will be presented which predict system performance. Efforts to assess technical risks involved in the development of the system will be discussed and the results of a recent experiment designed to evaluate background radiation levels will also be presented.

  20. Study of spallation target of ADS neutron source based on MCNPX%基于MCNPX对ADS中子源散裂靶的物理研究

    Institute of Scientific and Technical Information of China (English)

    时磊; 景桂芬

    2011-01-01

    The spallation target of Accelerator-Driven sub-critical System (ADS) is studied using the program MCNPX. The calculation of standard lead target bombarded with 0. 6 - 1. 5 GeV proton beams is carried out. The neutron spectra and distribution over the lead target,energy deposition and neutron production in the lead target are studied. The simulation results agree with the former theoretical and experimental results.%运用蒙卡程序MCNPX对加速器驱动次临界反应堆系统(简称ADS)的标准散裂中子靶进行了计算研究.计算了在0.6~1.5 GeV的质子轰击下,标准Pb靶发生散裂反应产生的中子产额及分布、中子能谱以及靶内能量沉积分布.计算结果与文献理论数据、实验数据进行了比较.

  1. Neutronic calculations for the design and optimization of the target-moderator-reflector system of the European Spallation Source (ESS); Calculos neutronicos para el diseno y optimizacion del sistema blanco-moderador de la Fuente Europea de Espalacion (ESS)

    Energy Technology Data Exchange (ETDEWEB)

    Domingo, S.; Sordo, F.; Magan, M.; Perlado, J. M.; Bermejo, J.

    2010-07-01

    The ESS has now entered a three to four years redesign phase in which the design of the target module raised in 2003 will be updated. The target group of ESS Bilbao, in collaboration with the Institute of Nuclear Fusion (Polytechnical University of Madrid), will perform a significant part of the neutronic calculations associated with this stage, especially focusing on the design and optimization of the target-moderator system of the European source. In this paper, the methodologies used, and some results obtained for the neutron performance of one of the conceptual alternatives, the stationary target with coaxial flow of liquid metal, are presented.

  2. Production of a {sup 44} Ti target and its cross section of thermal neutron capture; Producao de um alvo de {sup 44} Ti e sua secao de choque para captura de neutrons termicos

    Energy Technology Data Exchange (ETDEWEB)

    Ejnisman, R

    1993-12-31

    A study of the production of a {sup 44} Ti target was carried out aiming the determination of its thermal neutron capture cross-section. With this purpose, the cross-section of the reaction {sup 45} Sc(p,2 n) {sup 44} Ti was determined in the energies 16-, 18-, 20-22- and 45 MeV. The cross-section of the reactions (p,n) {sup 45} Ti, (p,pn) {sup 44m} Sc, (p,pn) {sup 44g} Sc and (p,p2n){sup 43} Sc were also measured. The results in the low energy region are in good agreement with a previous work by McGee et al. On the other hand, the cross-section at 45 MeV is different from McGee`s result and indicates the existence of an abnormal behavior of the excitation function at higher energies. Furthermore, a radiochemical separation method was developed in order to eliminate Sc from the {sup 44} Ti target which was irradiated with neutrons. It was possible to determine an upper limit for the cross-section of the reaction {sup 44} Ti (n, {gamma}) of 4 x 10{sup 3} b. At last, it is presented a discussion of the results obtained and their possible astrophysical implications. (author) 94 refs.

  3. Optimization of a neutron production target and a beam shaping assembly based on the 7Li( p, n) 7Be reaction for BNCT

    Science.gov (United States)

    Burlon, A. A.; Kreiner, A. J.; Valda, A. A.; Minsky, D. M.; Somacal, H. R.; Debray, M. E.; Stoliar, P.

    2005-02-01

    In this work a thick LiF target was studied through the 7Li( p, n) 7Be reaction as a neutron source for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT) to provide a testing ground for numerical simulations aimed at producing an optimized neutron production target and beam shaping assembly design. Proton beams in the 1.88-2.0 MeV energy range were produced with the tandem accelerator TANDAR ( TANDem ARgentino) at the Comisión Nacional de Energía Atómica (CNEA) in Buenos Aires, Argentina. A cylindrical water-filled head-phantom, containing a boric acid sample, was irradiated to study the resulting neutron flux. The dose deposited in the boric acid sample was inferred through the Compton-suppressed detection of the gamma radiation produced from the 10B( n, αγ) 7Li capture reaction. The thermal neutron flux was evaluated using bare and Cd-covered activation gold foils. In all cases, Monte Carlo simulations have been done showing good agreement with the experimental results. Extensive MCNP simulation trials have then been performed after the preliminary calculation tool validation in order to optimize a neutron beam shaping assembly. These simulations include a thick Li metal target (instead of LiF), a whole-body phantom, two different moderator-reflector assemblies (Al/AlF 3/LiF, Fluental ®, as moderator and lead as reflector and a combination of Al, PTFE (polytetrafluoroethylene) and LiF as moderator and lead as reflector) and the treatment room. The doses were evaluated for proton bombarding energies of 1.92 MeV (near to the threshold of the reaction), 2.0 MeV, 2.3 MeV (near the reaction resonance) and 2.5 MeV, and for three Fluental ® and Al/PTFE/LiF moderator thicknesses (18, 26 and 34 cm). In a later instance, the effect of the specific skin radiosensitivity (an RBE of 2.5 for the 10B( n, α) 7Li reaction) and a 10B uptake 50% greater than the healthy tissue one, was considered for the scalp. To evaluate the doses in the phantom, a comparison of

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

    Science.gov (United States)

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

    2004-01-01

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

  5. Characterization of the energy distribution of neutrons generated by 5 MeV protons on a thick beryllium target at different emission angles

    Energy Technology Data Exchange (ETDEWEB)

    Agosteo, S. [Politecnico di Milano, Dipartimento di Energia, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)] [Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, 20133 Milano (Italy); Colautti, P., E-mail: paolo.colautti@lnl.infn.it [INFN, Laboratori Nazionali di Legnaro (LNL), Via dell' Universita, 2, I-35020 Legnaro (PD) (Italy); Esposito, J., E-mail: juan.esposito@tin.it [INFN, Laboratori Nazionali di Legnaro (LNL), Via dell' Universita, 2, I-35020 Legnaro (PD) (Italy); Fazzi, A.; Introini, M.V.; Pola, A. [Politecnico di Milano, Dipartimento di Energia, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)] [Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, 20133 Milano (Italy)

    2011-12-15

    Neutron energy spectra at different emission angles, between 0 Degree-Sign and 120 Degree-Sign from the Be(p,xn) reaction generated by a beryllium thick-target bombarded with 5 MeV protons, have been measured at the Legnaro Laboratories (LNL) of the Italian National Institute for Nuclear Physics research (INFN). A new and quite compact recoil-proton spectrometer, based on a monolithic silicon telescope, coupled to a polyethylene converter, was efficiently used with respect to the traditional Time-of-Flight (TOF) technique. The measured distributions of recoil-protons were processed through an iterative unfolding algorithm in order to determine the neutron energy spectra at all the angles accounted for. The neutron energy spectrum measured at 0 Degree-Sign resulted to be in good agreement with the only one so far available at the requested energy and measured years ago with TOF technique. Moreover, the results obtained at different emission angles resulted to be consistent with detailed past measurements performed at 4 MeV protons at the same angles by TOF techniques.

  6. Ewald: an extended wide-angle Laue diffractometer for the second target station of the Spallation Neutron Source.

    Science.gov (United States)

    Coates, Leighton; Robertson, Lee

    2017-08-01

    Visualizing hydrogen atoms in biological materials is one of the biggest remaining challenges in biophysical analysis. While X-ray techniques have unrivaled capacity for high-throughput structure determination, neutron diffraction is uniquely sensitive to hydrogen atom positions in crystals of biological materials and can provide a more complete picture of the atomic and electronic structures of biological macromolecules. This information can be essential in providing predictive understanding and engineering control of key biological processes, for example, in catalysis, ligand binding and light harvesting, and to guide bioengineering of enzymes and drug design. One very common and large capability gap for all neutron atomic resolution single-crystal diffractometers is the weak flux of available neutron beams, which results in limited signal-to-noise ratios giving a requirement for sample volumes of at least 0.1 mm(3). The ability to operate on crystals an order of magnitude smaller (0.01 mm(3)) will open up new and more complex systems to studies with neutrons which will help in our understanding of enzyme mechanisms and enable us to improve drugs against multi resistant bacteria. With this is mind, an extended wide-angle Laue diffractometer, 'Ewald', has been designed, which can collect data using crystal volumes below 0.01 mm(3).

  7. Neutronic and nuclear post-test analysis of MEGAPIE

    Energy Technology Data Exchange (ETDEWEB)

    Zanini, L.; Aebersold, H. U.; Berg, K.; Eikenberg, J.; Filges, U.; Groeschel, F.; Luethy, M.; Ruethi, M.; Scazzi, S.; Tobler, L.; Wagner, W.; Wernli, B. [Paul Scherrer Institute (PSI), Villigen (Switzerland); Panebianco, S.; David, J.-C.; Dore, D.; Lemaire, S.; Leray, S.; Letourneau, A.; Michel-Sendis, F.; Prevost, A.; Ridikas, D.; Stankunas, G. [CEA, Centre de Saclay, IRFU/Service de Physique Nucleaire, Gif-sur-Yvette (France); Toussaint, J.-C. [CEA, Centre de Saclay, IRFU/Service d' Ingenierie des Systemes, Gif-sur-Yvette (France); Eid, M. [CEA, Centre de Saclay, DEN/DM2S/SERMA, Gif-sur-Yvette (France); Latge, C. [CEA, Centre de Cadarache, DEN/DTN/DIR, Saint Paul Lez, Durance (France); Konobeyev, A. Yu.; Fischer, U. [Institut fuer Reaktorsichereit, Forschungszentrum Karlsruhe Gmbh, Karlsruhe (Germany); Thiolliere, N.; Guertin, A. [SUBATECH Laboratory, CNRS/IN2P3-EMN-University, Nantes (France); Buchillier, T.; Bailat, C. [Institut universitaire de radiophysique appliquee (IRA), Lausanne (Switzerland)

    2008-12-15

    and MEGAPIE has been correctly reproduced. To achieve a good accuracy in the calculation of the neutronic performance of an ADS system, an accurate definition of the geometrical model taking into account the influence of structural materials is of primary importance. The results depend also on the beam profile used in the simulations, at least for the flux calculations close to the target interaction point. Radioactive nuclides produced in liquid metal targets are transported into hot cells, pumps or close to electronics with radiation sensitive components. Besides the considerable amount of decay {gamma} activity in the irradiated liquid metal, a significant amount of the Delayed Neutron (DN) precursor activity accumulates in the target fluid. The transit time of a liquid metal target being as short as a few seconds, DNs may contribute significantly to the activation and dose rates. The importance of the DN issues in liquid metal targets is confirmed. Another problem is the gas production and release in an ADS target, the proton beam generating a large amount of gas by spallation reactions. A large amount of Po isotopes, volatile at relatively high temperatures, are produced in the LBE. The gas production was measured by {gamma} spectroscopy. The release rates of noble gases in MEGAPIE are at the % level after 1-2 days of operation, while the release becomes almost complete weeks after the beginning of operation. Pressure increase in the cover gas could be reproduced with calculations within a factor of 2. The effect of the impurities in the radionuclide inventory of the LBE, using the actual chemical composition of the LBE used in MEGAPIE, is minimal.

  8. Optimization of the photoneutron target geometry for e-accelerator based BNCT.

    Science.gov (United States)

    Chegeni, Nahid; Pur, Saleh Boveiry; Razmjoo, Sasan; Hoseini, Seydeh Khadijed

    2017-06-01

    Today, electron accelerators are taken into consideration as photoneutron sources. Therefore, for maximum production of epithermal neutron flux, designing a photoneutron target is of significant importance. In this paper, the effect of thickness and geometric shape of a photoneutron target on neutron output were investigated. In this study, a pencil photon source with 13, 15, 18, 20 and 25 MeV energies and a diameter of 2 mm was investigated using Monte Carlo simulation method using MCNP code. To optimize the design of the photoneutron target, the tungsten target with various geometries and thicknesses was investigated. The maximum neutron flux produced for all target geometries and thicknesses occurred at neutron energy peak of around 0.46 MeV. As the thickness increased to 2 cm, neutron flux increased and then a decreasing trend was observed. For various geometrical shapes, the determining factor in photoneutron output was the effective target thickness in the photon interaction path that increased by the increase in the area of interaction. Another factor was the angle of the photon's incidence with the target surface that resulted in a significant decrease in photoneutron output in cone-shaped targets. Three factors including the total neutron flux, neutrons energy spectrum, and convergence of neutrons plays an important role in the selection of geometry and shape of the target that should be investigated considering beam shaping assembly (BSA) shape.

  9. Neutron scattering with deuterium labeling reveals the nature of complexes formed by Ca{sup 2+}-binding proteins and their regulatory targets

    Energy Technology Data Exchange (ETDEWEB)

    Trewhella, J. [Los Alamos National Laboratory, NM (United States)

    1994-12-01

    Small-angle neutron scattering with deuterium labeling is extremely useful for studying the structures of complex biomolecular assemblies in solution. The different neutron scattering properties of their isotopes of hydrogen combines with the ability to uniformly label biomolecules with deuterium allow one to characterize the structures and relative dispositions of the individual components of an assembly using methods of {open_quotes}contrast variation.{close_quotes} We have applied these techniques to studies of the evolutionarily related dumbbell-shaped Ca{sup 2+}-binding proteins calmodulin and troponin C and their interactions with the target proteins whose activities they regulate. Ca{sup 2+} is one of the simplest of nature`s messengers used in the communication pathways between physiological stimulus and cellular response. The signaling mechanism generally involves Ca{sup 2+} binding to a protein and inducing a conformational change that transmits a signal to modify the activity of a specific target protein. Ca{sup 2+} is thus important in the regulation of a diverse array of intracellular responses, including neurotransmitter release, muscle contraction, the degradation of glycogen to glucose to generate energy, microtubule assembly, membrane phosphorylation, etc. It is the conformational language of the Ca{sup 2+} induced signal transduction that we have sought to understand because of its central importance to biochemical regulation and, hence, to healthy cellular function.

  10. Synthesis and characterization of gadolinium nanostructured materials with potential applications in magnetic resonance imaging, neutron-capture therapy and targeted drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Stefanakis, Dimitrios; Ghanotakis, Demetrios F., E-mail: ghanotakis@chemistry.uoc.g [University of Crete, Department of Chemistry (Greece)

    2010-05-15

    Two Gadolinium nanostructured materials, Gd{sub 2}(OH){sub 5}NO{sub 3} nanoparticles and Gd(OH){sub 3} nanorods, were synthesized and extensively characterized by various techniques. In addition to the potential use of Gd{sub 2}(OH){sub 5}NO{sub 3} in magnetic resonance imaging (MRI) and Neutron-capture therapy (NCT) application, it could also be used in targeted drug delivery. An antibiotic (nalidixic acid), two amino acids (aspartic and glutamic acid), a fatty acid and a surfactant (SDS) were intercalated in the nanoparticles. The surface of the nanoparticles was modified with folic acid in order to be capable of targeted delivery to folate receptor expressing sites, such as tumor human cells.

  11. Analytical calculations and Monte-Carlo simulations of a high-resolution backscattering spectrometer for the long wavelength target station at the Spallation neutron source

    Science.gov (United States)

    Bordallo, H. N.; Herwig, K. W.; Zsigmond, G.

    2002-09-01

    Using the Monte-Carlo simulation programs McStas and VITESS, we present the design principles of the proposed high-resolution inverse geometry spectrometer on the Spallation neutron source (SNS)—long wavelength target station (LWTS). LWTS will enable the combination of large energy and momentum transfer ranges with energy resolution. Indeed the resolution of this spectrometer lie between that routinely achieved by spin echo techniques and the design goal of the high-power target station (HPTS) backscattering spectrometer. This niche of energy resolution is interesting for the study of slow motions of large objects and we are led to the domain of large molecules—polymers and biological molecules.

  12. Neutron generator for the array borehole logging

    Institute of Scientific and Technical Information of China (English)

    LuHong-Bo; ZhongZhen-Qian; 等

    1998-01-01

    The performance mechanism of the array neutron generator to be used to porosity logging is presented.The neutron generator utilizes a drive-in target ceramic neutron tube,which cursts nerutron with fast-slow period selectively pressure.Regulation of the neutron tube is accomplished by pulse width modulation.The high voltage power supply is poerated at optimum frequency.

  13. Novel isotretinoin microemulsion-based gel for targeted topical therapy of acne: formulation consideration, skin retention and skin irritation studies

    Science.gov (United States)

    Patel, Mrunali R.; Patel, Rashmin B.; Parikh, Jolly R.; Patel, Bharat G.

    2016-04-01

    Isotretinoin was formulated in novel microemulsion-based gel formulation with the aim of improving its solubility, skin tolerability, therapeutic efficacy, skin-targeting efficiency and patient compliance. Microemulsion was formulated by the spontaneous microemulsification method using 8 % isopropyl myristate, 24 % Labrasol, 8 % plurol oleique and 60 % water as an external phase. All plain and isotretinoin-loaded microemulsions were clear and showed physicochemical parameters for the desired topical delivery and stability. The permeation profiles of isotretinoin through rat skin from selected microemulsion formulation followed zero-order kinetics. Microemulsion-based gel was prepared by incorporating Carbopol®971 in optimized microemulsion formulation having suitable skin permeation rate and skin uptake. Microemulsion-based gel showed desired physicochemical parameters and demonstrated advantage over marketed formulation in improving the skin tolerability of isotretinoin, indicating its potential in improving topical delivery of isotretinoin. The developed microemulsion-based gel may be a potential drug delivery vehicle for targeted topical delivery of isotretinoin in the treatment of acne.

  14. Mild cognitive impairment (MCI) - the novel trend of targeting Alzheimer's disease in its early stages - methodological considerations.

    Science.gov (United States)

    Pater, C

    2011-11-01

    While much uncertainty exists in the estimates of the global burden of Alzheimer's disease and about the potential impact of various interventions, there is a widespread acceptance of the fact that the steady increase in the incidence and prevalence of the condition worldwide is becoming a massive public health problem as well as a huge economic burden for all healthcare systems and societies. These heavy demands are further compounded by the poor quality of life of the affected individuals, of their families and of their caregivers. The epidemic proportion of Alzheimer's disease has triggered relentless attempts for development of treatment approaches during the past two decades by a multitude of pharmaceuticals and biotech companies. Commercial development of the acetylcholinesterase inhibitors has, until recently, virtually dominated the field and, although efficacy has been demonstrated for five different products, the longterm clinical results suggested that alternate approaches were warranted. Disease modifying strategies targeting the β- amyloid plaques (e.g., decreasing β-amyloid formation through β- and γ-secretase inhibition, diminishing β-amyloid aggregation through anti-aggregants or enhancement of β-amyloid clearance through active/passive immunization), targeting the neurofibrillary tangles through inhibition of tau protein hyperphosphorilation or, more recently, by increasing mitochondrial permeability, all these potential treatment modalities are facing major methodological challenges during the conduct of a myriad of clinical trials meant to bring the novel therapies to the market. Failure of more than 400 products tested in more than 800 clinical trials to date, with many of these failures occurring in late stage development (phase III) have triggered a paradigm shift toward targeting of the early stages of cognitive deficiencies (mild cognitive impairment- MCI) and a refinement of the investigative methodologies. The great heterogeneity of

  15. Neutron effective dose calculation behind concrete shielding of charged particle accelerators with energy up to 100 MeV

    CERN Document Server

    Alejnikov, V E; Krylov, A R

    2002-01-01

    Calculation data of neutron effective dose behind concrete shielding with thickness up to 3 meters is presented. The calculations have been performed by the Monte Carlo and phenomenological methods for monoenergetic neutrons with energy from 5 to 100 MeV as well as for neutron spectra produced by protons with energies of 30 and 72 MeV in thick targets. Comparison between calculations of neutron effective dose behind shielding using phenomenological approach and those by the Monte Carlo method normally shows agreement to within a factor of better than two, i.e. estimation of shielding thickness by those methods shall not exceed one half value layer of neutron effective dose attenuation in shielding. It amounts from 10 to 30 cm of concrete shielding for neutron energies and thickness of shields under consideration

  16. Stellar 30-keV neutron capture in 94,96Zr and the 90Zr(gamma,n)89Zr photonuclear reaction with a high-power liquid-lithium target

    CERN Document Server

    Tessler, M; Arenshtam, A; Feinberg, G; Friedman, M; Halfon, S; Kijel, D; Weissman, L; Aviv, O; Berkovits, D; Eisen, Y; Eliyahu, I; Haquin, G; Kreisel, A; Mardor, I; Shimel, G; Shor, A; Silverman, I; Yungrais, Z

    2015-01-01

    A high-power Liquid-Lithium Target (LiLiT) was used for the first time for neutron production via the thick-target 7Li(p,n)7Be reaction and quantitative determination of neutron capture cross sections. Bombarded with a 1-2 mA proton beam at 1.92 MeV from the Soreq Applied Research Accelerator Facility (SARAF), the setup yields a 30-keV quasi-Maxwellian neutron spectrum with an intensity of 3-5e10 n/s, more than one order of magnitude larger than present near-threshold 7Li(p,n) neutron sources. The setup was used here to determine the 30-keV Maxwellian averaged cross section (MACS) of 94Zr and 96Zr as 28.0+-0.6 mb and 12.4+-0.5 mb respectively, based on activation measurements. The precision of the cross section determinations results both from the high neutron yield and from detailed simulations of the entire experimental setup. We plan to extend our experimental studies to low-abundance and radioactive targets. In addition, we show here that the setup yields intense high-energy (17.6 and 14.6 MeV) prompt cap...

  17. Characterization of lead-bismuth eutectic target material for accelerator driven transmuters

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Yousry E-mail: gohar@anl.gov

    2003-05-15

    Lead-bismuth eutectic (LBE) is under consideration as a target material with high-energy protons for generating neutrons to drive actinide and fission product transmuters. A characterization has been performed to study the performance of this target material as a function of the main variables and the design selections. The characterization includes the neutron yield, the spatial energy deposition, the neutron spectrum, the beam window performance, and the target buffer requirements. The characterization has also considered high-energy deuteron particles to study the impact on the target neutronic performance. The obtained results quantify the LBE target material performance with proton or deuteron particles as a function of the target variables and selections.

  18. Attenuation curves in concrete of neutrons from 100 to 400 MeV per nucleon He, C, Ne, Ar, Fe and Xe ions on various targets

    Science.gov (United States)

    Agosteo, S.; Nakamura, T.; Silari, M.; Zajacova, Z.

    2004-04-01

    Data on transmission of neutrons in concrete generated by heavy ions of intermediate energies (of typically up to 1 GeV per nucleon) are of interest for shielding design of accelerators for use in both the research and in the medical field. The energy distributions of neutrons produced by ions of different species (from He to Xe) striking various targets at energies from 100 to 800 MeV per nucleon were recently measured by Kurosawa et al. in the angular range 0-90°. These spectra were used as input data for Monte Carlo simulations to determine source terms and attenuation lengths in ordinary concrete. The present paper presents calculations for 100 MeV/u helium ions on a Cu target, 100 MeV/u carbon ions on C, Al, Cu and Pb, 100 MeV/u neon ions on Cu and Pb, 400 MeV/u carbon ions on C, Al, Cu and Pb, 400 MeV/u neon ions on Cu, 400 MeV/u Ar ions on Cu, 400 MeV/u Fe ions on Cu and 400 MeV/u Xe ions on Cu. The results include the contributions of all secondaries. Some of the resulting attenuation curves are best fitted by a double-exponential function rather than the usual single-exponential. The effect of various approximations introduced in the simulations is discussed. A comparison is made with shielding data for protons scaled with the ion mass number. A comparison is also made with a simple analytical model in use at GANIL.

  19. Transmutation of $^{239}$Pu and Other Nuclides Using Spallation Neutrons Produced by Relativistic Protons Reacting with Massive U- and Pb-Targets

    CERN Document Server

    Adam, J; Bamblevski, V P; Barabanov, M Yu; Bradnova, V; Chaloun, P; Hella, K M; Kalinnikov, V G; Krivopustov, M I; Kulakov, B A; Perelygin, V P; Pronskikh, V S; Pavliouk, A V; Solnyshkin, A A; Sosnin, A N; Stegailov, V I; Tsoupko-Sitnikov, V M; Zaverioukha, O S; Adloff, J C; Debeauvais, M; Brandt, R; Langrock, E J; Vater, P; Van, J S; Westmeier, W; Dwivedi, K K; Guo Shi Lun; Li Li Qiang; Hashemi-Nezhad, S R; Kievets, M K; Lomonosova, E M; Zhuk, I V; Modolo, G; Odoj, R; Zamani-Valassiadou, M

    2001-01-01

    Experimental studies on the transmutation of some long-lived radioactive waste nuclei, such as ^{129}I, ^{237}Np, and ^{239}Pu, as well as on natural uranium and lanthanum (all of them used as sensors) were carried out at the Synchrophasotron of the Laboratory for High Energies (JINR, Dubna). Spallation neutrons were produced by relativistic protons with energies in the range of 0.5 GeV\\le E(p)\\le 1.5 GeV interacting with 20 cm long uranium or lead target stacks. The targets were surrounded by 6 cm paraffin moderators. The radioactive sensors mentioned above were positioned on the outside surface of the moderator and contained typically approximately 0.5 up to 1 gram of long-lived isotopes. The highly radioactive targets were produced perfectly well-sealed in aluminum containers by the Institute of Physics and Power Engineering, Obninsk, Russia. From the experimentally observed transmutation rates one can easily extrapolate, that in a subcritical nuclear power assembly (or "energy amplifier") using a 10 mA pr...

  20. THERMAL NEUTRON BACKSCATTER IMAGING.

    Energy Technology Data Exchange (ETDEWEB)

    VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

    2004-10-16

    Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

  1. Engineering Novel Targeted Boron-10-Enriched Theranostic Nanomedicine to Combat against Murine Brain Tumors via MR Imaging-Guided Boron Neutron Capture Therapy.

    Science.gov (United States)

    Kuthala, Naresh; Vankayala, Raviraj; Li, Yi-Nan; Chiang, Chi-Shiun; Hwang, Kuo Chu

    2017-08-01

    Glioblastoma multiforme (GBM) is a very common type of "incurable" malignant brain tumor. Although many treatment options are currently available, most of them eventually fail due to its recurrence. Boron neutron capture therapy (BNCT) emerges as an alternative noninvasive therapeutic treatment modality. The major challenge in treating GBMs using BNCT is to achieve selective imaging, targeting, and sufficient accumulation of boron-containing drug at the tumor site so that effective destruction of tumor cells can be achieved without harming the normal brain cells. To tackle this challenge, this study demonstrates for the first time that an unprecedented (10) B-enriched (96% (10) B enrichment) boron nanoparticle nanomedicine ((10) BSGRF NPs) surface-modified with a Fluorescein isothiocyanate (FITC)-labeled RGD-K peptide can pass through the brain blood barrier, selectively target at GBM brain tumor sites, and deliver high therapeutic dosage (50.5 µg (10) B g(-1) cells) of boron atoms to tumor cells with a good tumor-to-blood boron ratio of 2.8. The (10) BSGRF NPs not only can enhance the contrast of magnetic resonance (MR) imaging to help diagnose the location/size/progress of brain tumor, but also effectively suppress murine brain tumors via MR imaging-guided BNCT, prolonging the half-life of mice from 22 d (untreated group) to 39 d. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Analysis of structure and deformation behavior of AISI 316L tensile specimens from the second operational target module at the Spallation Neutron Source

    Science.gov (United States)

    Gussev, M. N.; McClintock, D. A.; Garner, F. A.

    2016-01-01

    In an earlier publication, tensile testing was performed on specimens removed from the first two operational targets of the Spallation Neutron Source (SNS). There were several anomalous features in the results. First, some specimens had very large elongations (up to 57%) while others had significantly smaller values (10-30%). Second, there was a larger than the usual amount of data scatter in the elongation results. Third, the stress-strain diagrams of nominally similar specimens spanned a wide range of behavior ranging from expected irradiation-induced hardening to varying levels of force drop after yield point and indirect signs of "traveling deformation wave" behavior associated with strain-induced martensite formation. To investigate the cause(s) of such variable tensile behavior, several specimens from Target 2, spanning the range of observed tensile behavior, were chosen for detailed microstructural examination using electron backscatter diffraction (EBSD) analysis. It was shown that the steel employed in the construction of the target contained an unexpected bimodal grain size distribution, containing very large out-of-specification grains surrounded by "necklaces" of grains of within-specification sizes. The large grains were frequently comparable to the width of the gauge section of the tensile specimen. The propensity to form martensite during deformation was shown to be accelerated by radiation but also to be very sensitive to the relative orientation of the grains with respect to the tensile axis. Specimens having large grains in the gauge that were most favorably oriented for production of martensite strongly exhibited the traveling deformation wave phenomenon, while those specimens with less favorably oriented grains had lesser or no degree of the wave effect, thereby accounting for the observed data scatter.

  3. Versatile inelastic neutron spectrometer (VINS) project for J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T.J. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Shirakata, Tokai, Ibaraki 319-1106 (Japan)], E-mail: taku@issp.u-tokyo.ac.jp; Yamamuro, O.; Hirota, K.; Shibayama, M.; Yoshizawa, H. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Shirakata, Tokai, Ibaraki 319-1106 (Japan); Itoh, S. [High Energy Accerelator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan); Watanabe, S.; Asami, T. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Shirakata, Tokai, Ibaraki 319-1106 (Japan); Kindo, K.; Uwatoko, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwanoha, Chiba 277-8581 (Japan); Kanaya, T. [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Higashi, N.; Ueno, K. [High Energy Accerelator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2009-02-21

    We have proposed a Versatile Inelastic Neutron Spectrometer (VINS) for the spallation neutron source at the Materials and Life Science Facility (MLF), Japan Proton Accelerator Research Complex (J-PARC). VINS is a direct-geometry Fermi chopper spectrometer designed to provide considerably high neutron flux with moderate energy and Q resolutions. VINS is characterized by its wide energy and Q range (0.5<{delta}E<1000 meV and Q< 40 A{sup -1} at {delta}E=1000 meV), enabled by an array of detectors covering large solid angle [-30 deg.<2{theta}<130 deg. horizontally and -30 deg.<{phi}<30 deg. vertically (2.8 Sr)]. Monte Carlo ray-tracing simulation estimates the sample position neutron flux as high as roughly 1x10{sup 6} neutrons cm{sup -2} s{sup -1} for the {delta}E/E{sub i}{approx}5% mode at E{sub i}=10 meV. With these wide E-Q coverage and high neutron flux, VINS will be one of the most efficient and versatile inelastic spectrometers at J-PARC. Target science ranges from conventional solid-state physics, such as highly correlated electron systems, frustrated magnets and relaxors, to rather interdisciplinary areas, exemplified by glasses, quasicrystals, polymers and liquids. A particular focus is placed on extreme sample environments; high magnetic-field and high-pressure environments are planned.

  4. TARGET:?

    National Research Council Canada - National Science Library

    James M Acton

    2014-01-01

      By 2003. as military planners had become worried that the country's long-range conventional weapons, such as cruise missiles, might be too slow to reach hypothetical distant targets that needed to be struck urgently...

  5. Neutron production station ESS-BILBAO; Estacion de produccion de neutrones de ESS-BILBAO

    Energy Technology Data Exchange (ETDEWEB)

    Vicente Bueno, J. Pe. de; Bermejo, J.; Fraile Santiago, T.

    2012-07-01

    The ESS-Bilbao installation produces neutrons by nuclear reactions stripping energy 50 MeV protons on a target of beryllium. the Neutron Production Station would have a target and would allow condition the neutron energy, maximize their performance, provide structural support to the whole, the high power cooling and radiation shielding received abroad.

  6. Stellar 30-keV neutron capture in 94, 96Zr and the Zr90(γ,nZr89 photonuclear reaction with a high-power liquid-lithium target

    Directory of Open Access Journals (Sweden)

    M. Tessler

    2015-12-01

    Full Text Available A high-power Liquid-Lithium Target (LiLiT was used for the first time for neutron production via the thick-target Li7(p,nBe7 reaction and quantitative determination of neutron capture cross sections. Bombarded with a 1–2 mA proton beam at 1.92 MeV from the Soreq Applied Research Accelerator Facility (SARAF, the setup yields a 30-keV quasi-Maxwellian neutron spectrum with an intensity of 3–5×1010 n/s, more than one order of magnitude larger than present near-threshold Li7(p,n neutron sources. The setup was used here to determine the 30-keV Maxwellian averaged cross section (MACS of 94Zr and 96Zr as 28.0±0.6 mb and 12.4±0.5 mb respectively, based on activation measurements. The precision of the cross section determinations results both from the high neutron yield and from detailed simulations of the entire experimental setup. We plan to extend our experimental studies to low-abundance and radioactive targets. In addition, we show here that the setup yields intense high-energy (17.6 and 14.6 MeV prompt capture γ rays from the Li7(p,γBe8 reaction with yields of ∼3×108γs−1mA−1 and ∼4×108γs−1mA−1, respectively, evidenced by the Zr90(γ,nZr89 photonuclear reaction.

  7. Study of 232Th(n, γ) and 232Th(n,f) reaction rates in a graphite moderated spallation neutron field produced by 1.6 GeV deuterons on lead target

    Science.gov (United States)

    Asquith, N. L.; Hashemi-Nezhad, S. R.; Westmeier, W.; Zhuk, I.; Tyutyunnikov, S.; Adam, J.

    2015-02-01

    The Gamma-3 assembly of the Joint Institute for Nuclear Research (JINR), Dubna, Russia is designed to emulate the neutron spectrum of a thermal Accelerator Driven System (ADS). It consists of a lead spallation target surrounded by reactor grade graphite. The target was irradiated with 1.6 GeV deuterons from the Nuclotron accelerator and the neutron capture and fission rate of 232Th in several locations within the assembly were experimentally measured. 232Th is a proposed fuel for envisaged Accelerator Driven Systems and these two reactions are fundamental to the performance and feasibility of 232Th in an ADS. The irradiation of the Gamma-3 assembly was also simulated using MCNPX 2.7 with the INCL4 intra-nuclear cascade and ABLA fission/evaporation models. Good agreement between the experimentally measured and calculated reaction rates was found. This serves as a good validation for the computational models and cross section data used to simulate neutron production and transport of spallation neutrons within a thermal ADS.

  8. Neutron Repulsion

    OpenAIRE

    Manuel, Oliver K.

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch...

  9. Measurement of the Isoscalar Monopole Response in the Neutron-Rich Nucleus 68Ni using the Active Target MAYA

    Science.gov (United States)

    Vandebrouck, M.; Gibelin, J.; Khan, E.; Achouri, N. L.; Baba, H.; Beaumel, D.; Blumenfeld, Y.; Caamaño, M.; Càceres, L.; Colò, G.; Delaunay, F.; Fernandez-Dominguez, B.; Garg, U.; Grinyer, G. F.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Keeley, N.; Mittig, W.; Pancin, J.; Raabe, R.; Roger, T.; Roussel-Chomaz, P.; Savajols, H.; Sorlin, O.; Stodel, C.; Suzuki, D.; Thomas, J. C.

    We report the measurement of the isoscalar monopole strength in the unstable nucleus 68Ni using inelastic alpha scattering at 50A MeV in inverse kinematics. This experiment has been performed at GANIL with LISE spectrometer using a dedicated detector: the active target MAYA. A part of the isoscalar giant monopole resonance (ISGMR) has been measured at 21.1 ± 1.9 MeV and indications for a soft monopole mode are provided for the first time at 12.9 ± 1.0 MeV. Distorted-wave born approximation (DWBA) with random-phase approximation (RPA) transition densities have been used to study angular distribution and indicate that the L = 0 multipolarity dominates the cross-section for the ISGMR, and significantly contributes to the soft mode.

  10. Design Considerations for mHealth Programs Targeting Smokers Not Yet Ready to Quit: Results of a Sequential Mixed-Methods Study

    Science.gov (United States)

    Heffner, Jaimee; Hohl, Sarah; Klasnja, Predrag; Catz, Sheryl L

    2017-01-01

    Background Mobile health (mHealth) smoking cessation programs are typically designed for smokers who are ready to quit smoking. In contrast, most smokers want to quit someday but are not yet ready to quit. If mHealth apps were designed for these smokers, they could potentially encourage and assist more people to quit smoking. No prior studies have specifically examined the design considerations of mHealth apps targeting smokers who are not yet ready to quit. Objective To inform the user-centered design of mHealth apps for smokers who were not yet ready to quit by assessing (1) whether these smokers were interested in using mHealth tools to change their smoking behavior; (2) their preferred features, functionality, and content of mHealth programs addressing smoking; and (3) considerations for marketing or distributing these programs to promote their uptake. Methods We conducted a sequential exploratory, mixed-methods study. Qualitative interviews (phase 1, n=15) were completed with a demographically diverse group of smokers who were smartphone owners and wanted to quit smoking someday, but not yet. Findings informed a Web-based survey of smokers from across the United States (phase 2, n=116). Data were collected from April to September, 2016. Results Findings confirmed that although smokers not yet ready to quit are not actively seeking treatment or using cessation apps, most would be interested in using these programs to help them reduce or change their smoking behavior. Among phase 2 survey respondents, the app features, functions, and content rated most highly were (1) security of personal information; (2) the ability to track smoking, spending, and savings; (3) content that adaptively changes with one’s needs; (4) the ability to request support as needed; (5) the ability to earn and redeem awards for program use; (6) guidance on how to quit smoking; and (7) content specifically addressing management of nicotine withdrawal, stress, depression, and anxiety

  11. Design Considerations for mHealth Programs Targeting Smokers Not Yet Ready to Quit: Results of a Sequential Mixed-Methods Study.

    Science.gov (United States)

    McClure, Jennifer B; Heffner, Jaimee; Hohl, Sarah; Klasnja, Predrag; Catz, Sheryl L

    2017-03-10

    Mobile health (mHealth) smoking cessation programs are typically designed for smokers who are ready to quit smoking. In contrast, most smokers want to quit someday but are not yet ready to quit. If mHealth apps were designed for these smokers, they could potentially encourage and assist more people to quit smoking. No prior studies have specifically examined the design considerations of mHealth apps targeting smokers who are not yet ready to quit. To inform the user-centered design of mHealth apps for smokers who were not yet ready to quit by assessing (1) whether these smokers were interested in using mHealth tools to change their smoking behavior; (2) their preferred features, functionality, and content of mHealth programs addressing smoking; and (3) considerations for marketing or distributing these programs to promote their uptake. We conducted a sequential exploratory, mixed-methods study. Qualitative interviews (phase 1, n=15) were completed with a demographically diverse group of smokers who were smartphone owners and wanted to quit smoking someday, but not yet. Findings informed a Web-based survey of smokers from across the United States (phase 2, n=116). Data were collected from April to September, 2016. Findings confirmed that although smokers not yet ready to quit are not actively seeking treatment or using cessation apps, most would be interested in using these programs to help them reduce or change their smoking behavior. Among phase 2 survey respondents, the app features, functions, and content rated most highly were (1) security of personal information; (2) the ability to track smoking, spending, and savings; (3) content that adaptively changes with one's needs; (4) the ability to request support as needed; (5) the ability to earn and redeem awards for program use; (6) guidance on how to quit smoking; and (7) content specifically addressing management of nicotine withdrawal, stress, depression, and anxiety. Results generally did not vary by stage of

  12. Simulation experiments for gamma-ray mapping of planetary surfaces: Scattering of high-energy neutrons

    Science.gov (United States)

    Brueckner, J.; Englert, P.; Reedy, R. C.; Waenke, H.

    1986-01-01

    The concentration and distribution of certain elements in surface layers of planetary objects specify constraints on models of their origin and evolution. This information can be obtained by means of remote sensing gamma-ray spectroscopy, as planned for a number of future space missions, i.e., Mars, Moon, asteroids, and comets. To investigate the gamma-rays made by interactions of neutrons with matter, thin targets of different composition were placed between a neutron-source and a high-resolution germanium spectrometer. Gamma-rays in the range of 0.1 to 8 MeV were accumulated. In one set of experiments a 14-MeV neutron generator using the T(d,n) reaction as neutron-source was placed in a small room. Scattering in surrounding walls produced a spectrum of neutron energies from 14 MeV down to thermal. This complex neutron-source induced mainly neutron-capture lines and only a few scattering lines. As a result of the set-up, there was a considerable background of discrete lines from surrounding materials. A similar situation exists under planetary exploration conditions: gamma-rays are induced in the planetary surface as well as in the spacecraft. To investigate the contribution of neutrons with higher energies, an experiment for the measurement of prompt gamma radiation was set up at the end of a beam-line of an isochronous cyclotron.

  13. Outline of spallation neutron source engineering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Noboru [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2001-01-01

    Slow neutrons such as cold and thermal neutrons are unique probes which can determine structures and dynamics of condensed matter in atomic scale. The neutron scattering technique is indispensable not only for basic sciences such as condensed matter research and life science, but also for basic industrial technology in 21 century. It is believed that to survive in the science-technology competition in 21 century would be almost impossible without neutron scattering. However, the intensity of neutrons presently available is much lower than synchrotron radiation sources, etc. Thus, R and D of intense neutron sources become most important. The High-Intensity Proton Accelerator Project is now being promoted jointly by Japan Atomic Energy Research Institute and High Energy Accelerator Research Organization, but there has so far been no good text which covers all the aspects of pulsed spallation neutron sources. The present review was prepare aiming at giving a better understanding on pulsed spallation neutron sources not only to neutron source researchers but also more widely to neutron scattering researchers and accelerator scientists in this field. The contents involve, starting from what is neutron scattering and what neutrons are necessary for neutron scattering, what is the spallation reaction, how to produce neutrons required for neutron scattering more efficiently, target-moderator-reflector neutronics and its engineering, shielding, target station, material issues, etc. The author have engaged in R and D of pulsed apallation neutron sources and neutron scattering research using them over 30 years. The present review is prepared based on the author's experiences with useful information obtained through ICANS collaboration and recent data from the JSNS (Japanese Spallation Neutron Source) design team. (author)

  14. Energy-dispersive study of the interactions of fast neutrons with matter

    CERN Document Server

    Altstadt, E; Eckert, S; Freiesleben, H; Galindo, V; Grosse, E; Naumann, B; Weiss, F P

    2003-01-01

    The construction and the first use of a compact time-of-flight system for the energy-dispersive study of the interaction of fast neutrons with materials are content of a network project of the Research Center Rossendorf, to which also the Technical University Dresden contributes in the framework of a common DFG project. The planned time-of-flight experiments with pulsed neutrons will be performed at the radiation source ELBE. First results on the development of a neutron-production target are presented. By means of radiation-transport and finite-element programs the distributions of the energy deposition of the used pulsed electron beam of the radiation source ELBE and the temperature in the neutron radiator as well as the expected particle spectra and fluxes at the measurement place were calculated. Considerations on the development of a beam catcher are discussed.

  15. Shielding Experiments Under JASMIN Collaboration at Fermilab(III) - Measurement of High-Energy Neutrons Penetrating a Thick Iron Shield from the Antiproton Production Target by AU Activation Method

    CERN Document Server

    Matsumura, H; Iwase, H; Toyoda, A; Kasugai, Y; Matsuda, N; Sakamoto, Y; Nakashima, H; Yashima, H; Mokhov, N; Leveling, A; Boehlein, D; Vaziri, K; Lautenschlager, G; Schmitt, W; Oishi, K

    2012-01-01

    In an antiproton production (Pbar) target station of the Fermi National Accelerator Laboratory (FNAL), the secondary particles produced by bombarding a target with 120-GeV protons are shielded by a thick iron shield. In order to obtain experimental data on high-energy neutron transport at more than 100-GeV-proton accelerator facilities, we indirectly measured more than 100-MeV neutrons at the outside of the iron shield at an angle of 50{\\deg} in the Pbar target station. The measurement was performed by using the Au activation method coupled with a low-background {\\gamma}-ray counting system. As an indicator for the neutron flux, we determined the production rates of 8 spallation nuclides (196-Au, 188-Pt, 189-Ir, 185-Os, 175-Hf, 173-Lu, 171-Lu, and 169-Yb) in the Au activation detector. The measured production rates were compared with the theoretical production rates calculated using PHITS. We proved that the Au activation method can serve as a powerful tool for indirect measurements of more than 100-MeV neutr...

  16. Measurement of neutron scattering lengths using neutron interferometry

    Science.gov (United States)

    Shahi, Chandra B.

    This thesis describes the details on building a new Neutron Interferometry and Optics Facility (NIOFa), the measurement of the incoherent neutron scattering length bi of 3He, and the measurement of the coherent neutron scattering length bc of 4He at National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). A new monochromatic beamline and facility has been installed at the NCNR devoted to neutron interferometry in the research areas of spin control, spin manipulation, quantum mechanics, quantum information science, spintronics, and material science. This facility is possible in part because of advances in decoherence free subspace interferometer designs that have demonstrated consistent contrast in the presence of vibrational noise; a major environmental constraint that has prevented neutron interferometry from being applied at other neutron facilities. This new facility, NIOFa, is located in the guide hall of the NCNR upstream of the existing Neutron Interferometry and Optics Facility (NIOF) and has several advantages over the NIOF including higher incident flux, better neutron polarization, and increased accessibility. The measurement of the incoherent neutron scattering length bi of 3He was done using a (220) single silicon crystal skew symmetric interferometer. This experiment requires both a polarized beam and a polarized target. We report bi = -2.35 +/- 0.014 (stat.) +/- 0.014 (syst.). This experiment is a revision of the previous experiment which was done in 2008, and partially explains the non-zero phase shift seen in 2008 experiment even if target cell was completely unpolarized. The measurement of the coherent neutron scattering length b c of the 4He was done using a (111) single silicon crystal interferometer. The neutron interferometry and optics facility at NIST had been used previously to determine the coherent scattering lengths for n- 1H, n-2H, and n-3He to less than 1% relative uncertainty. We report bc of the 4He

  17. Neutron scattering studies in the actinide region

    Energy Technology Data Exchange (ETDEWEB)

    Beghian, L.E.; Kegel, G.H.R.

    1991-08-01

    During the report period we have investigated the following areas: Neutron elastic and inelastic scattering measurements on {sup 14}N, {sup 181}Ta, {sup 232}Th, {sup 238}U and {sup 239}Pu; Prompt fission spectra for {sup 232}Th, {sup 235}U, {sup 238}U and {sup 239}Pu; Theoretical studies of neutron scattering; Neutron filters; New detector systems; and Upgrading of neutron target assembly, data acquisition system, and accelerator/beam-line apparatus.

  18. Neutron Radiography

    Science.gov (United States)

    Heller, A. K.; Brenizer, J. S.

    Neutron radiography and its related two-dimensional (2D) neutron imaging techniques have been established as invaluable nondestructive inspection methods and quantitative measurement tools. They have been used in a wide variety of applications ranging from inspection of aircraft engine turbine blades to study of two-phase fluid flow in operating proton exchange membrane fuel cells. Neutron radiography is similar to X-ray radiography in that the method produces a 2D attenuation map of neutron radiation that has penetrated the object being examined. However, the images produced differ and are often complementary due to the differences between X-ray and neutron interaction mechanisms. The uses and types of 2D neutron imaging have expanded over the past 15 years as a result of advances in imaging technology and improvements in neutron generators/sources and computers. Still, high-intensity sources such as those from reactors and spallation neutron sources, together with conventional film radiography, remain the mainstay of high-resolution, large field-of-view neutron imaging. This chapter presents a summary of the history, methods, and related variations of neutron radiography techniques.

  19. Neutron radioactivity-Lifetime measurements of neutron-unbound states

    Science.gov (United States)

    Kahlbow, J.; Caesar, C.; Aumann, T.; Panin, V.; Paschalis, S.; Scheit, H.; Simon, H.

    2017-09-01

    A new technique to measure the lifetime τ of a neutron-radioactive nucleus that decays in-flight via neutron emission is presented and demonstrated utilizing MonteCarlo simulations. The method is based on the production of the neutron-unbound nucleus in a target, which at the same time slows down the produced nucleus and the residual nucleus after (multi-) neutron emission. The spectrum of the velocity difference of neutron(s) and the residual nucleus has a characteristic shape, that allows to extract the lifetime. If the decay happens outside the target there will be a peak in the spectrum, while events where the decay is in the target show a broad flat distribution due to the continuous slowing down of the residual nucleus. The method itself and the analysis procedure are discussed in detail for the specific candidate 26O. A stack of targets with decreasing target thicknesses can expand the measurable lifetime range and improve the sensitivity by increasing the ratio between decays outside and inside the target. The simulations indicate a lower limit of measurable lifetime τ ∼ 0 . 2 ps for the given conditions.

  20. Uniformly rotating neutron stars

    CERN Document Server

    Boshkayev, Kuantay

    2016-01-01

    In this chapter we review the recent results on the equilibrium configurations of static and uniformly rotating neutron stars within the Hartle formalism. We start from the Einstein-Maxwell-Thomas-Fermi equations formulated and extended by Belvedere et al. (2012, 2014). We demonstrate how to conduct numerical integration of these equations for different central densities ${\\it \\rho}_c$ and angular velocities $\\Omega$ and compute the static $M^{stat}$ and rotating $M^{rot}$ masses, polar $R_p$ and equatorial $R_{\\rm eq}$ radii, eccentricity $\\epsilon$, moment of inertia $I$, angular momentum $J$, as well as the quadrupole moment $Q$ of the rotating configurations. In order to fulfill the stability criteria of rotating neutron stars we take into considerations the Keplerian mass-shedding limit and the axisymmetric secular instability. Furthermore, we construct the novel mass-radius relations, calculate the maximum mass and minimum rotation periods (maximum frequencies) of neutron stars. Eventually, we compare a...

  1. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  2. J-PARC and the prospective neutron sciences

    Indian Academy of Sciences (India)

    Masatoshi Arai

    2008-10-01

    Overview of the neutron target system, instrument suite and perspective neutron sciences of J-PARC are described. The neutron facility of J-PARC, JSNS, will be operated from May 2008. JSNS will be a 1 MW pulsed spallation neutron source. About 10 high performance instruments are under construction to be ready by the Day-One.

  3. Theory of neutron star magnetospheres

    CERN Document Server

    Curtis Michel, F

    1990-01-01

    An incomparable reference for astrophysicists studying pulsars and other kinds of neutron stars, "Theory of Neutron Star Magnetospheres" sums up two decades of astrophysical research. It provides in one volume the most important findings to date on this topic, essential to astrophysicists faced with a huge and widely scattered literature. F. Curtis Michel, who was among the first theorists to propose a neutron star model for radio pulsars, analyzes competing models of pulsars, radio emission models, winds and jets from pulsars, pulsating X-ray sources, gamma-ray burst sources, and other neutron-star driven phenomena. Although the book places primary emphasis on theoretical essentials, it also provides a considerable introduction to the observational data and its organization. Michel emphasizes the problems and uncertainties that have arisen in the research as well as the considerable progress that has been made to date.

  4. Neutron Albedo

    CERN Document Server

    Ignatovich, V K

    2005-01-01

    A new, algebraic, method is applied to calculation of neutron albedo from substance to check the claim that use of ultradispersive fuel and moderator of an active core can help to gain in size and mass of the reactor. In a model of isotropic distribution of incident and reflected neutrons it is shown that coherent scattering on separate grains in the case of thermal neutrons increases transport cross section negligibly, however it decreases albedo from a wall of finite thickness because of decrease of substance density. A visible increase of albedo takes place only for neutrons with wave length of the order of the size of a single grain.

  5. Low-mass neutron stars: universal relations, the nuclear symmetry energy and gravitational radiation

    Science.gov (United States)

    Silva, Hector O.; Sotani, Hajime; Berti, Emanuele

    2016-07-01

    The lowest neutron star masses currently measured are in the range 1.0-1.1 M⊙, but these measurement have either large uncertainties or refer to isolated neutron stars. The recent claim of a precisely measured mass M/M⊙ = 1.174 ± 0.004 (Martinez et al. 2015) in a double neutron star system suggests that low-mass neutron stars may be an interesting target for gravitational-wave detectors. Furthermore, Sotani et al. recently found empirical formulas relating the mass and surface redshift of non-rotating neutron stars to the star's central density and to the parameter η ≡ (K0L2)1/3, where K0 is the incompressibility of symmetric nuclear matter and L is the slope of the symmetry energy at saturation density. Motivated by these considerations, we extend the work by Sotani et al. to slowly rotating and tidally deformed neutron stars. We compute the moment of inertia, quadrupole moment, quadrupole ellipticity, tidal and rotational Love number and apsidal constant of slowly rotating neutron stars by integrating the Hartle-Thorne equations at second order in rotation, and we fit all of these quantities as functions of η and of the central density. These fits may be used to constrain η, either via observations of binary pulsars in the electromagnetic spectrum, or via near-future observations of inspiralling compact binaries in the gravitational-wave spectrum.

  6. Intense neutron pulse generation in dense Z-pinch

    Science.gov (United States)

    Bystritskii, V. M.; Glusko, Yu. A.; Mesyats, G. A.; Ratakhin, N. A.

    1989-12-01

    The problem of intense neutron pulse generation with fast dense Z-pinches (ZP) is analyzed for a modified approach. The analysis pertains to the interaction of a High Power Deuterium Beam (HPDB) with hot (Te≂1 keV) deuterium target formed by a ZP. The considerable decrease of the Coulomb ion-electron scattering cross-sections gives a corresponding increase of the deuterium range and neutron yield in the hot target. The generation of HPDB and ZP formation takes place at the same terawatt accelerator, by using in series with the ZP a plasma opening switch (POS), which is at the same time the Ion Plasma Filled Diode (IPFD). During the front of the current pulse the stable z-pinch implosion heats the ZP up to the keV temperature range with several kJ of energy input. Near the end of the current front the energy flow is being switched to HPDB generation due to the opening of the POS. The HPDB is focused ballistically at the axis of the ZP and transported along it in the azimutal magnetic field, producing a neutron burst. The analysis of ZP formation and heating, HPDB generation, its transport and neutron production is given.

  7. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  8. Statistical model calculations of pre-scission neutron multiplicity for the heavy ion induced fusion-fission reactions with actinide target 232Th

    Directory of Open Access Journals (Sweden)

    Thakur Meenu

    2015-01-01

    Full Text Available The reaction mechanism of 19F + 232Th and 28Si + 232Th systems populating the near-super-heavy compound nuclei 251Es and 260Rf respectively are investigated using neutron multiplicity as a probe. The prescission neutron multiplicities of these compound nuclei are calculated at different excitation energies using a statistical model code. These calculations are performed using the Bohr-Wheeler transition state fission width as well as the dissipative dynamical fission width based on the Kramers’ prescription. For 19F + 232Th system, the measured yield of pre-scission is compared with the statistical model calculations for the decay of a compound nucleus in the excitation energy range of 54-90 MeV. The comparison between the measured and the calculated values indicates that the Bohr-Wheeler fission width underestimates the pre-scission neutron yield and a large amount of dissipation strength is required to reproduce the experimental pre-scission neutron multiplicities. The excitation energy dependence of the fitted values of the dissipation coefficient is also discussed. In addition, exploratory statistical model calculations of pre-scission neutron multiplicity for the 28Si + 232Th system are presented in the above range of excitation energy.

  9. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index......Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... to hundreds of nanometers. Thickness resolution for flat surfaces is in the range of few Ǻngstrøm, and as a peculiar benefit, the presence and properties of buried interfaces are accessible. Focus here will be on neutron reflectometry, a technique that is unique in applications involving composite organic...

  10. Status of ITER neutron diagnostic development

    Science.gov (United States)

    Krasilnikov, A. V.; Sasao, M.; Kaschuck, Yu. A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V. S.; Popovichev, S.; Iguchi, T.; Jarvis, O. N.; Källne, J.; Fiore, C. L.; Roquemore, A. L.; Heidbrink, W. W.; Fisher, R.; Gorini, G.; Prosvirin, D. V.; Tsutskikh, A. Yu.; Donné, A. J. H.; Costley, A. E.; Walker, C. I.

    2005-12-01

    Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be measured well by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors (NFMs), neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The NFMs need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented.

  11. Measurement of neutron diffraction with compact neutron source RANS

    Science.gov (United States)

    Ikeda, Y.; Takamura, M.; Taketani, A.; Sunaga, H.; Otake, Y.; Suzuki, H.; Kumagai, M.; Oba, Y.; Hama, T.

    2016-11-01

    Diffraction is used as a measurement technique for crystal structure. X-rays or electron beam with wavelength that is close to the lattice constant of the crystal is often used for the measurement. They have sensitivity in surface (0.01mm) of heavy metals due to the mean free path for heavy ions. Neutron diffraction has the probe of the internal structure of the heavy metals because it has a longer mean free path than that of the X-rays or the electrons. However, the neutron diffraction measurement is not widely used because large facilities are required in the many neutron sources. RANS (Riken Accelerator-driven Compact Neutron Source) is developed as a neutron source which is usable easily in laboratories and factories. In RANS, fast neutrons are generated by 7MeV protons colliding on a Be target. Some fast neutrons are moderated with polyethylene to thermal neutrons. The thermal neutrons of 10meV which have wavelength of 10nm can be used for the diffraction measurement. In this study, the texture evolution in steels was measured with RANS and the validity of the compact neutron source was proved. The texture of IF steel sheets with the thickness of 1.0mm was measured with 10minutes run. The resolution is 2% and is enough to analyze a evolution in texture due to compression/tensile deformation or a volume fraction of two phases in the steel sample. These results have proven the possibility to use compact neutron source for the analysis of mesoscopic structure of metallic materials.

  12. Overview of the Neutron experimental facilities at LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-30

    This presentation gives an overview of the neutron experimental facilities at LANSCE. The layout is mentioned in detail, with a map of the south-side experimental facilities, information on Target-4 and the Lujan Center. Then it goes into detail about neutron sources, specifically continuous versus pulsed. Target 4 is then discussed. In conclusion, we have introduced the south-side experimental facilities in operation at LANSCE. 1L target and Target 4 provide complementary neutron energy spectra. Two spallation neutron sources taken together cover more than 11 orders of magnitude in neutron energy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gierga, D.P.; Yanch, J.C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Shefer, R.E. [Newton Scientific, Inc., Cambridge, MA (United States)

    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.

  14. Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

    Science.gov (United States)

    Čufar, Aljaž; Batistoni, Paola; Conroy, Sean; Ghani, Zamir; Lengar, Igor; Milocco, Alberto; Packer, Lee; Pillon, Mario; Popovichev, Sergey; Snoj, Luka

    2017-03-01

    At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium-tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle-energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

  15. Analyses of silicon dioxide, magnesium oxide, lead fluoride, bismuth as low-pass velocity filters for neutrons

    Science.gov (United States)

    Connor, D.; Holmryd, S.

    1969-01-01

    Transmission measurement of neutrons by filter materials for low energy neutrons is important for the study of structure and dynamics of condensed matter. Since only thermal neutrons are useful for such experiments, filter materials that transmit thermal neutrons while attenuating fast neutrons and gamma rays are of considerable interest.

  16. Neutronic design and characteristics of the RRR

    Energy Technology Data Exchange (ETDEWEB)

    Villarino, Eduardo A.; Korochinsky, Sergio; Hergenreder, Daniel [INVAP S.E., Bariloche, Rio Negro (Argentina)

    2002-07-01

    This paper describes the general neutronic characteristics of the Replacement Research Reactor (RRR) for the Australian Nuclear Science and Technology Organisation (ANSTO). The description covers different aspect of the neutronic design: fuel assemblies (FA) characteristics, irradiation facilities, requirements, operational requirements, etc. An important neutronic characteristic of the RRR design is that it handles two types of FA, the well-known and qualified U{sub 3}Si{sub 2} fuel type and the under qualification process U-Mo FA type. Several irradiation facilities are located around the reactor core. Three types of neutron sources: a cold neutron source with two tangential beams and several neutron guides, a thermal neutron beam with two beams and several neutron guides, and a room reserved for a future hot neutron source with a beam. The core has also 17 vertical irradiation tubes with 5 targets each for bulk radioisotope production (for example: Ir, Mo and I), 19 pneumatic rigs with 58 target positions for different purposes: radioisotope production, neutron activation analysis (NAA). Finally it has 6 neutron transmutation doping (NTD) facilities. A general description and main characteristics of the present core design is also given. (author)

  17. Neutron Time-Of-Flight (n_TOF) experiment

    CERN Multimedia

    Brugger, M; Jericha, E; Cortes rossell, G P; Riego perez, A; Baccomi, R; Laurent, B G; Palomo pinto, F R; Griesmayer, E; Leeb, H; Dressler, M; Cano ott, D; Variale, V; Ventura, A; Carrillo de albornoz trillo, A; Lo meo, S; Andrzejewski, J J; Pavlik, A F; Kadi, Y; Zanni vlastou, R; Krticka, M; Weiss, C; Kokkoris, M; Praena rodriguez, A J; Cortes giraldo, M A; Perkowski, J; Losito, R; Audouin, L; Tagliente, G; Wallner, A; Woods, P J; Mengoni, A; Guerrero sanchez, C G; Tain enriquez, J L; Vlachoudis, V; Calviani, M; Reifarth, R; Mendoza cembranos, E; Quesada molina, J M; Schumann, M D; Tsinganis, A; Saxena, A; Rauscher, T; Calvino tavares, F; Bondarenko, I; Mingrone, F; Gonzalez romero, E M; Colonna, N; Negret, A L; Leal cidoncha, E; Chiaveri, E; Milazzo, P M; Ferro pereira goncalves, I M; De almeida carrapico, C A; Castelluccio, D M

    The neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.

  18. Modeling a neutron rich nuclei source

    Energy Technology Data Exchange (ETDEWEB)

    Mirea, M.; Bajeat, O.; Clapier, F.; Ibrahim, F.; Mueller, A.C.; Pauwels, N.; Proust, J. [Institut de Physique Nucleaire, IN2P3/CNRS, 91 - Orsay (France); Mirea, M. [Institute of Physics and Nuclear Engineering, Tandem Lab., Bucharest (Romania)

    2000-07-01

    The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron rich nuclei based on the neutron induced fission can be realised using these beams. A theoretical optimization of such a facility as a function of the incident deuteron energy is reported. The model used to determine the fission products takes into account the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with a converter-target specific geometry. (author000.

  19. Cooling of Neutron Stars

    Directory of Open Access Journals (Sweden)

    Grigorian H.

    2010-10-01

    Full Text Available We introduce the theoretical basis for modeling the cooling evolution of compact stars starting from Boltzmann equations in curved space-time. We open a discussion on observational verification of different neutron star models by consistent statistics. Particular interest has the question of existence of quark matter deep inside of compact object, which has to have a specific influence on the cooling history of the star. Besides of consideration of several constraints and features of cooling evolution, which are susceptible of being critical for internal structure of hot compact stars we have introduced a method of extraction of the mass distribution of the neutron stars from temperature and age data. The resulting mass distribution has been compared with the one suggested by supernove simulations. This method can be considered as an additional checking tool for the consistency of theoretical modeling of neutron stars. We conclude that the cooling data allowed existence of neutron stars with quark cores even with one-flavor quark matter.

  20. Neutron dose equivalent rate for heavy ion bombardment

    Institute of Scientific and Technical Information of China (English)

    LiGui-Sheng; ZhangTian-Mei; 等

    1998-01-01

    The fluence rate distribution of neutrons in the reactionsof 50MeV/u 18O-ion on thick Be,Cu and Au targets have been measured with an activation method of threshold detectors andthe neutron dose equivalent rate distributions at 1m from the tqrgets in intermediate energy heavy ion target area are obtained by using the conversion factors from neutron fluence rate to neutron doseequivalent rate.

  1. Optimization of Shielded Scintillator for Neutron Detection

    Science.gov (United States)

    Belancourt, Patrick; Morrison, John; Akli, Kramer; Freeman, Richard; High Energy Density Physics Team

    2011-10-01

    The High Energy Density Physics group is interested in the basic science of creating a neutron and gamma ray source. The neutrons and gamma rays are produced by accelerating ions via a laser into a target and creating fusion neutrons and gamma rays. A scintillator and photomultiplier tube will be used to detect these neutrons. Neutrons and photons produce ionizing radiation in the scintillator which then activates metastable states. These metastable states have both short and long decay rates. The initial photon count is orders of magnitude higher than the neutron count and poses problems for accurately detecting the neutrons due to the long decay state that is activated by the photons. The effects of adding lead shielding on the temporal response and signal level of the neutron detector will be studied in an effort to minimize the photon count without significant reduction to the temporal resolution of the detector. MCNP5 will be used to find the temporal response and energy deposition into the scintillator by adding lead shielding. Results from the simulations will be shown. Optimization of our scintillator neutron detection system is needed to resolve the neutron energies and neutron count of a novel neutron and gamma ray source.

  2. Materials for spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, W.F.; Daemen, L.L. [comps.

    1996-03-01

    The Workshop on Materials for Spallation Neutron Sources at the Los Alamos Neutron Science Center, February 6 to 10, 1995, gathered scientists from Department of Energy national laboratories, other federal institutions, universities, and industry to discuss areas in which work is needed, successful designs and use of materials, and opportunities for further studies. During the first day of the workshop, speakers presented overviews of current spallation neutron sources. During the next 3 days, seven panels allowed speakers to present information on a variety of topics ranging from experimental and theoretical considerations on radiation damage to materials safety issues. An attempt was made to identify specific problems that require attention within the context of spallation neutron sources. This proceedings is a collection of summaries from the overview sessions and the panel presentations.

  3. Neutron, electron and photon transport in ICF tragets in direct and fast ignition

    Directory of Open Access Journals (Sweden)

    A. Parvazian

    2005-12-01

    Full Text Available Fusion energy due to inertial confinement has progressed in the last few decades. In order to increase energy efficiency in this method various designs have been presented. The standard scheme for direct ignition and fast ignition fuel targets are considered. Neutrons, electrons and photons transport in targets containing different combinations of Li and Be are calculated in both direct and fast ignition schemes. To compress spherical multilayer targets having fuel in the central part, they are irradiated by laser or heavy ion beams. Neutrons energy deposition in the target is considered using Monte Carlo method code MCNP. A significant amount of neutrons energy is deposited in the target which resulted in growing fusion reactions rates. It is found that Beryllium compared to Lithium is more important. In an introductory consideration of relativistic electron beam transport into central part of a fast ignition target, we have calculated electron energy deposition in highly dense D-T fuel and Beryllium layer of the target. It has been concluded that a fast ignition scheme is preferred to direct ignition because of the absence of hydrodynamic instability.

  4. Low-mass neutron stars: universal relations, the nuclear symmetry energy and gravitational radiation

    CERN Document Server

    Silva, Hector O; Berti, Emanuele

    2016-01-01

    The lowest neutron star masses currently measured are in the range $1.0-1.1~M_\\odot$, but these measurement have either large uncertainties or refer to isolated neutron stars. The recent claim of a precisely measured mass $M/M_{\\odot} = 1.174 \\pm 0.004$ by Martinez et al [Astrophys.J. 812, 143 (2015)] in a double neutron star system suggests that low-mass neutron stars may be an interesting target for gravitational-wave detectors. Furthermore, Sotani et al [PTEP 2014, 051E01 (2014)] recently found empirical formulas relating the mass and surface redshift of nonrotating neutron stars to the star's central density and to the parameter $\\eta\\equiv (K_0 L^2)^{1/3}$, where $K_0$ is the incompressibility of symmetric nuclear matter and $L$ is the slope of the symmetry energy at saturation density. Motivated by these considerations, we extend the work by Sotani et al to slowly rotating and tidally deformed neutron stars. We compute the moment of inertia, quadrupole moment, quadrupole ellipticity, tidal and rotationa...

  5. New experimental possibility to search for the ratio of a possible T-violating amplitude to the weak-interaction amplitude in polarized neutron transmission through a polarized nuclear target

    CERN Document Server

    Lukashevich, V V; Dallman, David

    2011-01-01

    This paper considers a spin-dependent neutron interaction with optical potentials (fields) from the strong interaction, the weak interaction, and an assumed T-violating interaction. The vector sum of these fields and their interferences determines an effective field of the target with an angular position in space due to polar and azimuthal angles. The phase of the azimuthal component is found to be the sum of two angles. The tangent of the first angle is equal to the ratio of the T-violating forward-scattering amplitude D to the weak-interaction amplitude C. The quantity is of interest. The tangent of the second angle depends on the spin rotation in the residual pseudomagnetic field of the target, and it can be treated as a background effect. This paper shows that the second angle has different signs in measurements with polarized and unpolarized neutrons; thus, two measurements allow it to be compensated for. In addition, the use of the Ramsey method of separated oscillatory fields for measurement of the neu...

  6. Development of Enhanced, Permanently-Installed, Neutron Activation Diagnostic Hardware for NIF

    Science.gov (United States)

    Edwards, E. R.; Jedlovec, D. R.; Carrera, J. A.; Yeamans, C. B.

    2016-05-01

    Neutron activation diagnostics are baseline neutron yield and flux measurement instruments at the National Ignition Facility. Up to 19 activation samples are distributed around the target chamber. Currently the samples must be removed to be counted, creating a 1-2 week data turn-around time and considerable labor costs. An improved system consisting of a commercially available LaBr3(Ce) scintillator and Power over Ethernet electronics is under development. A machined zirconium-702 cap over the detector is the activation medium to measure the 90Zr(n,2n)89Zr reaction. The detectors are located at the current neutron activation diagnostic sites and monitored remotely. Because they collect data in real time yield values are returned within a few hours after a NIF shot.

  7. Neutron Repulsion

    CERN Document Server

    Manuel, Oliver K

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding...

  8. The accelerator neutron source for boron neutron capture therapy

    Science.gov (United States)

    Kasatov, D.; Koshkarev, A.; Kuznetsov, A.; Makarov, A.; Ostreinov, Yu; Shchudlo, I.; Sorokin, I.; Sycheva, T.; Taskaev, S.; Zaidi, L.

    2016-11-01

    The accelerator based epithermal neutron source for Boron Neutron Capture Therapy (BNCT) is proposed, created and used in the Budker Institute of Nuclear Physics. In 2014, with the support of the Russian Science Foundation created the BNCT laboratory for the purpose to the end of 2016 get the neutron flux, suitable for BNCT. For getting 3 mA 2.3 MeV proton beam, was created a new type accelerator - tandem accelerator with vacuum isolation. On this moment, we have a stationary proton beam with 2.3 MeV and current 1.75 mA. Generation of neutrons is carried out by dropping proton beam on to lithium target as a result of threshold reaction 7Li(p,n)7Be. Established facility is a unique scientific installation. It provides a generating of neutron flux, including a monochromatic energy neutrons, gamma radiation, alpha-particles and positrons, and may be used by other research groups for carrying out scientific researches. The article describes an accelerator neutron source, presents and discusses the result of experiments and declares future plans.

  9. MCNPX Simulations for Neutron Cross Section Measurements

    OpenAIRE

    Tesinsky, Milan

    2010-01-01

    This thesis presents MCNPX simulations of the SCANDAL set-up used at the Theodor Svedberg Laboratory for neutron scattering cross-section measurements. The thesis describes processes and data important for the upcoming off-line data analysis. In the experiment, neutrons scattered off the target are converted to protons which are stopped in scintillator crystals. The results of presented simulations include a description of the proton spectra in dependence of the neutron-to-proton conversion a...

  10. Neutron Lifetime Measurement Using Magnetically Trapped Ultracold Neutrons

    Science.gov (United States)

    Huffer, Craig; Huffman, P. R.; Schelhammer, K. W.; Dewey, M. S.; Huber, M. G.; Hughes, P. P.; Mumm, H. P.; Thompson, A. K.; Coakley, K.; Yue, A. T.; O'Shaughnessy, C. M.

    2017-01-01

    The neutron beta-decay lifetime is important in both nuclear astrophysics and in understanding weak interactions in the framework of the Standard Model. An experiment based at the NIST Center for Neutron Research was designed to address statistical and systematic limitations of former measurements. In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (decays the energetic electron produces a scintillation signal in the helium that is detected in real time using photomultiplier tubes. The current measurement is limited by larger than expected systematic corrections. We will discuss the result of the latest dataset and comment on the potential of future measurements.

  11. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Heger, G. [Rheinisch-Westfaelische Technische Hochschule Aachen, Inst. fuer Kristallographie, Aachen (Germany)

    1996-12-31

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs.

  12. Prompt Fission Neutron Spectra of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Capote, R; Chen, Y J; Hambsch, F J; Kornilov, N V; Lestone, J P; Litaize, O; Morillon, B; Neudecker, D; Oberstedt, S; Ohsawa, T; Smith, D. L.

    2016-01-01

    The energy spectrum of prompt neutrons emitted in fission (PFNS) plays a very important role in nuclear science and technology. A Coordinated Research Project (CRP) “Evaluation of Prompt Fission Neutron Spectra of Actinides”was established by the IAEA Nuclear Data Section in 2009, with the major goal to produce new PFNS evaluations with uncertainties for actinide nuclei. The following technical areas were addressed: (i) experiments and uncertainty quantification (UQ): New data for neutron-induced fission of 233U, 235U, 238U, and 239Pu have been measured, and older data have been compiled and reassessed. There is evidence from the experimental work of this CRP that a very small percentage of neutrons emitted in fission are actually scission neutrons; (ii) modeling: The Los Alamos model (LAM) continues to be the workhorse for PFNS evaluations. Monte Carlo models have been developed that describe the fission phenomena microscopically, but further development is needed to produce PFNS evaluations meeting the uncertainty targets; (iii) evaluation methodologies: PFNS evaluations rely on the use of the least-squares techniques for merging experimental and model data. Considerable insight was achieved on how to deal with the problem of too small uncertainties in PFNS evaluations. The importance of considering that all experimental PFNS data are “shape” data was stressed; (iv) PFNS evaluations: New evaluations, including covariance data, were generated for major actinides including 1) non-model GMA evaluations of the 235U(nth,f), 239Pu(nth,f), and 233U(nth,f) PFNS based exclusively on experimental data (0.02 ≤ E ≤ 10 MeV), which resulted in PFNS average energies E of 2.00±0.01, 2.073±0.010, and 2.030±0.013 MeV, respectively; 2) LAM evaluations of neutron-induced fission spectra on uranium and plutonium targets with improved UQ for incident energies from thermal up to 30 MeV; and 3) Point-by-Point calculations for 232Th, 234U and 237Np targets; and (v) data

  13. Comparison of RNAi Sequences in Insect-Resistant Plants to Expressed Sequences of a Beneficial Lady Beetle: A Closer Look at Off-Target Considerations

    Directory of Open Access Journals (Sweden)

    Margaret L. Allen

    2017-03-01

    Full Text Available Sequences obtained from transcriptomes of the lady beetle Coleomegilla maculata were compared to those designed for incorporation into crops. Searches of the transcriptomes identified sequences as the most likely to be closely similar to the sequences described in RNAi plant incorporated products. Some proposed prime RNAi pest management targets were also used to identify predicted orthologs from C. maculata. The lady beetle sequences were aligned with sequences from corn rootworms and Colorado potato beetles and, as appropriate in the case of targets, regions of similarity were compared with the genetic model organism for beetles, Tribolium castaneum. Some high levels of nucleotide identity were identified, particularly with an actin-derived sequence from Colorado potato beetle. This actin-derived sequence shared identical sequences with the lady beetle and a parasitic wasp.

  14. Comparison of RNAi Sequences in Insect-Resistant Plants to Expressed Sequences of a Beneficial Lady Beetle: A Closer Look at Off-Target Considerations.

    Science.gov (United States)

    Allen, Margaret L

    2017-03-01

    Sequences obtained from transcriptomes of the lady beetle Coleomegilla maculata were compared to those designed for incorporation into crops. Searches of the transcriptomes identified sequences as the most likely to be closely similar to the sequences described in RNAi plant incorporated products. Some proposed prime RNAi pest management targets were also used to identify predicted orthologs from C. maculata. The lady beetle sequences were aligned with sequences from corn rootworms and Colorado potato beetles and, as appropriate in the case of targets, regions of similarity were compared with the genetic model organism for beetles, Tribolium castaneum. Some high levels of nucleotide identity were identified, particularly with an actin-derived sequence from Colorado potato beetle. This actin-derived sequence shared identical sequences with the lady beetle and a parasitic wasp.

  15. Neutron transport simulation (selected topics)

    Energy Technology Data Exchange (ETDEWEB)

    Vaz, P. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, P-2686-953 Sacavem (Portugal)], E-mail: pedrovaz@itn.pt

    2009-10-15

    Neutron transport simulation is usually performed for criticality, power distribution, activation, scattering, dosimetry and shielding problems, among others. During the last fifteen years, innovative technological applications have been proposed (Accelerator Driven Systems, Energy Amplifiers, Spallation Neutron Sources, etc.), involving the utilization of intermediate energies (hundreds of MeV) and high-intensity (tens of mA) proton accelerators impinging in targets of high Z elements. Additionally, the use of protons, neutrons and light ions for medical applications (hadrontherapy) impose requirements on neutron dosimetry-related quantities (such as kerma factors) for biologically relevant materials, in the energy range starting at several tens of MeV. Shielding and activation related problems associated to the operation of high-energy proton accelerators, emerging space-related applications and aircrew dosimetry-related topics are also fields of intense activity requiring as accurate as possible medium- and high-energy neutron (and other hadrons) transport simulation. These applications impose specific requirements on cross-section data for structural materials, targets, actinides and biologically relevant materials. Emerging nuclear energy systems and next generation nuclear reactors also impose requirements on accurate neutron transport calculations and on cross-section data needs for structural materials, coolants and nuclear fuel materials, aiming at improved safety and detailed thermal-hydraulics and radiation damage studies. In this review paper, the state-of-the-art in the computational tools and methodologies available to perform neutron transport simulation is presented. Proton- and neutron-induced cross-section data needs and requirements are discussed. Hot topics are pinpointed, prospective views are provided and future trends identified.

  16. Neutron transport simulation (selected topics)

    Science.gov (United States)

    Vaz, P.

    2009-10-01

    Neutron transport simulation is usually performed for criticality, power distribution, activation, scattering, dosimetry and shielding problems, among others. During the last fifteen years, innovative technological applications have been proposed (Accelerator Driven Systems, Energy Amplifiers, Spallation Neutron Sources, etc.), involving the utilization of intermediate energies (hundreds of MeV) and high-intensity (tens of mA) proton accelerators impinging in targets of high Z elements. Additionally, the use of protons, neutrons and light ions for medical applications (hadrontherapy) impose requirements on neutron dosimetry-related quantities (such as kerma factors) for biologically relevant materials, in the energy range starting at several tens of MeV. Shielding and activation related problems associated to the operation of high-energy proton accelerators, emerging space-related applications and aircrew dosimetry-related topics are also fields of intense activity requiring as accurate as possible medium- and high-energy neutron (and other hadrons) transport simulation. These applications impose specific requirements on cross-section data for structural materials, targets, actinides and biologically relevant materials. Emerging nuclear energy systems and next generation nuclear reactors also impose requirements on accurate neutron transport calculations and on cross-section data needs for structural materials, coolants and nuclear fuel materials, aiming at improved safety and detailed thermal-hydraulics and radiation damage studies. In this review paper, the state-of-the-art in the computational tools and methodologies available to perform neutron transport simulation is presented. Proton- and neutron-induced cross-section data needs and requirements are discussed. Hot topics are pinpointed, prospective views are provided and future trends identified.

  17. Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-06-01

    This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the time is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.

  18. Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

    CERN Document Server

    Anders, M; Bellini, A; Aliotta, M; Bemmerer, D; Broggini, C; Caciolli, A; Costantini, H; Corvisiero, P; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Alvarez, C Rossi; Scott, D; Somorjai, E; Straniero, O; Szücs, T

    2013-01-01

    The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction....

  19. Neutron tomography

    Science.gov (United States)

    Crump, James C., III; Richards, Wade J.; Shields, Kevin C.

    1995-07-01

    The McClellan Nuclear Radiation Center's (MNRC) staff in conjunction with a Cooperative Research and Development Agreement (CRDA) with the U.C. Santa Barbara facility has developed a system that can be used for aircraft inspection of jet engine blades. The problem was to develop an inspection system that can detect very low concentrations of hydrogen (i.e., greater than 100 ppm) in metal matricies. Specifically in Titanium alloy jet engine blades. Entrapment and precipitation of hydrogen in metals is an undesirable phenomenon which occurs in many alloys of steel and titanium. In general, metals suffer a loss of mechanical properties after long exposures to hydrogen, especially at high temperatures and pressures, thereby becoming embrittled. Neutron radiography has been used as a nondestructive testing technique for many years. Neutrons, because of their unique interactions with materials, are especially useful in the detection of hydrogen. They have an extremely high interaction cross section for low atomic number nuclei (i.e., hydrogen). Thus hydrogen in a metal matrix can be visualized using neutrons. Traditional radiography is sensitive to the total attenuation integrated over the path of radiation through the material. Increased sensitivity and quantitative cross section resolution can be obtained using three-dimensional volumetric imaging techniques such as tomography. The solution used to solve the problem was to develop a neutron tomography system. The neutron source is the McClellan Nuclear Radiation Center's 1 MW TRIGA reactor. This paper describes the hardware used in the system as well as some of the preliminary results.

  20. Neutrons from Antiproton Irradiation

    DEFF Research Database (Denmark)

    Bassler, Niels; Holzscheiter, Michael; Petersen, Jørgen B.B.

    Background: Radiotherapy with Antiprotons is currently investigated by the AD-4/ACE collaboration. The hypothesis is that the additional energy released from the antiprotons annihilating at the target nuclei can enable a reduced dose in the entry channel of the primary beam. Furthermore an enhanced...... relative biological effect (RBE) has already been beam measured in spread out Bragg peaks of antiprotons, relative to that found in the plateau region. However, the antiproton annihilation process is associated with a substantial release of secondary particles which contribute to the dose outside...... the neutron spectrum. Additionally, we used a cylindrical polystyrene loaded with several pairs of thermoluminescent detectors containing Lithium-6 and Lithium-7, which effectively detects thermalized neutrons. The obtained results are compared with FLUKA imulations. Results: The results obtained...

  1. Powder neutron diffractometers HRPT and DMCG

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P.; Doenni, A.; Staub, U.; Zolliker, M. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    Basic properties and applications of SINQ powder neutron diffractometers are described. For optimum use of the continuous neutron beams these instruments are equipped with position sensitive detectors, and both high-intensity and high-resolution modes of operation are possible. HRPT attaining resolutions {delta}d/d{<=}10{sup -3}, d=lattice spacing, at a thermal neutron channel of the target station and DMCG at a cold neutron guide coated with m=2 supermirrors, are complementary concerning the applications: the former will be mainly used for structural studies and the latter to investigate magnetic ordering phenomena. (author) figs., tabs., refs.

  2. The high intensity neutron source FRANZ

    CERN Document Server

    Lederer, Claudia

    2014-01-01

    The Frankfurt neutron source of Stern Gerlach Zentrum FRANZ is currently under construction at the University of Frankfurt. At FRANZ, a high intensity neutron beam in the keV energy region will be produced by bombarding a $^7$Li target with a proton beam of several mA. These unprecedented high neutron fluxes will allow a number of neutron induced cross section measurements for the first time. Measurements can be performed by the time-of-flight and by the activation technique.

  3. Paul Scherrer Institut Scientific Report 2001. Volume III: Condensed Matter Research with Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, J.; Castellazzi, D.; Shea-Braun, M. (eds.)

    2002-03-01

    The SINQ-facility stopped operation at the end of the year 2001 for the scheduled shut down. By that time the spallation target of the 'Cannelloni'-type (D{sub 2}O-cooled steel pins filled with lead) had received a total charge of more then 10 Ah at an average proton current higher than 1 mA. Thereby nearly 4 mols of neutrons had been released from this target. The two operational years with this target delivered the neutrons for about 300 experiments. During this operational period not one single interrupt caused by the spallation target has been recorded -indeed a convincing evidence for the reliability of this system. The probes inserted into the target and some of its parts will now soon be available to the materials scientists for careful investigation. SINQ as a continuous spallation neutron source was considered to be a 'high risk' project. Furthermore it was often accompanied with the suspicion to represent the 'worst of two worlds' - meaning that this facility would suffer from the disadvantages but not benefit from the advantage of a spallation neutron source - the pulse structure. According to our operational experience these fears are not justified provided the various concerns have been properly taken into consideration during design and construction. This report testifies what can be achieved at a continuous spallation neutron source. We believe that these research activities compare well with those from a beam-tube reactor of medium flux. A list of scientific publications in 2000 is also provided.

  4. Inclusive deuteron-induced reactions and final neutron states

    CERN Document Server

    Potel, Gregory; Thompson, Ian J

    2015-01-01

    We present in this paper a formalism for deuteron-induced inclusive reactions. We disentangle direct elastic breakup contributions from other processes (which we generically call non-elastic breakup) implying a capture of the neutron both above and below the neutron emission threshold. The reaction is described as a two step process, namely the breakup of the deuteron followed by the propagation of the neutron-target system driven by an optical potential. The final state interaction between the neutron and the target can eventually form an excited compound nucleus. Within this context, the direct neutron transfer to a sharp bound state is a limiting case of the present formalism.

  5. Measurement of double differential cross sections for light charged particles production in neutron induced reaction at 62.7 MeV on lead target; Mesures des sections efficaces doublement differentielles de production de particules chargees legeres lors de reactions induites par neutrons de 62.7 MeV sur cible de plomb

    Energy Technology Data Exchange (ETDEWEB)

    Kerveno, M

    2000-09-27

    In order to develop new options for nuclear waste management, studies are carrying out on the perfecting of hybrid systems (sub-critical reactor driven by accelerator). This thesis work takes place more precisely in the framework of nuclear data linked to hybrid systems development. Increasing the upper limit energy value (from 20 to 150 MeV) of data bases supposes that theoretical codes could have sufficient predictive power in this energy range. Thus it's necessary to measure new cross sections to constrain these codes. The experiment, performed at Louvain-la-Neuve Cyclotron, aims to determine the double differential cross sections for light charged particles production in neutron induced reactions at 62.7 MeV on natural lead target. The detection device consists of 6 NE102-CsI telescopes. Time of flight measurements are used to reconstruct the neutron energy spectra. The general framework (hybrid systems and associated nuclear data problematic) in which this work takes place is presented in a first part. The experimental set up used for our measurements is described in a second part. The three following parts are dedicated to the data analysis and double differential cross sections extraction. The particle discrimination, the energy calibration of detectors as the different corrections applied to the experimental spectra are related in details. And finally a comparative study between our experimental results and some theoretical predictions is presented. (author)

  6. Cyclotron-based neutron source for BNCT

    Science.gov (United States)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    2013-04-01

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation & treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8×109 neutrons/cm2/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with 10B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  7. Cyclotron-based neutron source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)

    2013-04-19

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  8. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    to hundreds of nanometers. Thickness resolution for flat surfaces is in the range of few Ǻngstrøm, and as a peculiar benefit, the presence and properties of buried interfaces are accessible. Focus here will be on neutron reflectometry, a technique that is unique in applications involving composite organic...... of desired information. In the course, an introduction into the method and an overview on selected instruments at large scale facilities will be presented. Examples will be given that illustrate the potential of the method, mostly based on organic films. Results from the investigation of layered films...... and the detection on nanoscopic roughnesses will be shown. The potential of neutron reflectometry is not only of academic origin. It may turn out to be useful in the design and development of new functional materials even though it will never develop into a standard method to be applied in the product control...

  9. a Portable Pulsed Neutron Generator

    Science.gov (United States)

    Skoulakis, A.; Androulakis, G. C.; Clark, E. L.; Hassan, S. M.; Lee, P.; Chatzakis, J.; Bakarezos, M.; Dimitriou, V.; Petridis, C.; Papadogiannis, N. A.; Tatarakis, M.

    2014-02-01

    The design and construction of a pulsed plasma focus device to be used as a portable neutron source for material analysis such as explosive detection using gamma spectroscopy is presented. The device is capable of operating at a repetitive rate of a few Hz. When deuterium gas is used, up to 105 neutrons per shot are expected to be produced with a temporal pulse width of a few tens of nanoseconds. The pulsed operation of the device and its portable size are its main advantage in comparison with the existing continuous neutron sources. Parts of the device include the electrical charging unit, the capacitor bank, the spark switch (spark gap), the trigger unit and the vacuum-fuel chamber / anode-cathode. Numerical simulations are used for the simulation of the electrical characteristics of the device including the scaling of the capacitor bank energies with total current, the pinch current, and the scaling of neutron yields with energies and currents. The MCNPX code is used to simulate the moderation of the produced neutrons in a simplified geometry and subsequently, the interaction of thermal neutrons with a test target and the corresponding prompt γ-ray generation.

  10. Spallation neutron experiment at SATURNE

    Energy Technology Data Exchange (ETDEWEB)

    Meigo, Shin-ichiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-11-01

    The double differential cross sections for (p,xn) reactions and the spectra of neutrons produced from the thick target have been measured at SATURNE in SACLAY from 1994 to 1997. The status of the experiment and the preliminary experimental results are presented. (author)

  11. Development of a neutron generator facility at Simon Fraser University

    OpenAIRE

    2015-01-01

    A new neutron generator facility at Simon Fraser University (SFU) utilizes a commercial deuterium-tritium neutron generator (Thermo Scientific P 385) to produce 14.2 MeV neutrons at a nominal rate of 3E8 neutrons/s. The facility will be used to produce radioisotopes to support a research program including nuclear structure studies and neutron activation analysis. As a prerequisite for regular operation of the facility and as a personnel safety consideration, dose rate predictions for the fa...

  12. Nondiffractive applications of neutrons at the spallation source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    The paper delivers an overview about experiments with neutrons from the spallation source SINQ which are not especially devoted to neutron scattering. A total of six experimental facilities are under construction using thermal as well as cold neutrons. Starting with some general considerations about the interaction of neutrons with matter, the principles, boundary conditions and the experimental set up of these experiments are described briefly. Some more details are given for the neutron radiography facility NEUTRA as the author`s special interest and research field. (author) 7 figs., 2 tabs., 9 refs.

  13. Magnetic field devices for neutron spin transport and manipulation in precise neutron spin rotation measurements

    Science.gov (United States)

    Maldonado-Velázquez, M.; Barrón-Palos, L.; Crawford, C.; Snow, W. M.

    2017-05-01

    The neutron spin is a critical degree of freedom for many precision measurements using low-energy neutrons. Fundamental symmetries and interactions can be studied using polarized neutrons. Parity-violation (PV) in the hadronic weak interaction and the search for exotic forces that depend on the relative spin and velocity, are two questions of fundamental physics that can be studied via the neutron spin rotations that arise from the interaction of polarized cold neutrons and unpolarized matter. The Neutron Spin Rotation (NSR) collaboration developed a neutron polarimeter, capable of determining neutron spin rotations of the order of 10-7 rad per meter of traversed material. This paper describes two key components of the NSR apparatus, responsible for the transport and manipulation of the spin of the neutrons before and after the target region, which is surrounded by magnetic shielding and where residual magnetic fields need to be below 100 μG. These magnetic field devices, called input and output coils, provide the magnetic field for adiabatic transport of the neutron spin in the regions outside the magnetic shielding while producing a sharp nonadiabatic transition of the neutron spin when entering/exiting the low-magnetic-field region. In addition, the coils are self contained, forcing the return magnetic flux into a compact region of space to minimize fringe fields outside. The design of the input and output coils is based on the magnetic scalar potential method.

  14. Neutrons are flying

    CERN Multimedia

    2000-01-01

    View of the n_TOF tube with members of the design and construction team of the facility(from left to right: R. Magnin/LHC, E. Radermacher/EP, P. Cennini/EP and R. Cappi/PS). A new experimental facility was inaugurated at CERN on Wednesday 8 November. The neutron Time Of Flight (n_TOF) facility received its first protons from the PS at 10:55. With an intensity of 1 x 1011 protons per cycle on the n_TOF target, an intense neutron beam has been produced at CERN for the first time, opening the door to many new avenues of research including, for example, neutron induced cross-section measurements. The facility is an offspring of the work by Carlo Rubbia and his group on the novel idea of an Energy Amplifier. The basic idea was successfully tested at the PS with the FEAT experiment and later with the TARC experiment, where the feasibility of transmutation of long-lived products by Adiabatic Resonance Crossing (ARC) was confirmed. This led to the possibility of radio-isotope production for medical applications, fo...

  15. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  16. Advanced Neutron Spectrometer

    Science.gov (United States)

    Christl, Mark; Dobson, Chris; Norwood, Joseph; Kayatin, Matthew; Apple, Jeff; Gibson, Brian; Dietz, Kurt; Benson, Carl; Smith, Dennis; Howard, David; hide

    2013-01-01

    Energetic neutron measurements remain a challenge for space science investigations and radiation monitoring for human exploration beyond LEO. We are investigating a new composite scintillator design that uses Li6 glass scintillator embedded in a PVT block. A comparison between Li6 and Boron 10 loaded scintillators are being studied to assess the advantages and shortcomings of these two techniques. We present the details of the new Li6 design and results from the comparison of the B10 and Li6 techniques during exposures in a mixed radiation field produced by high energy protons interacting in a target material.

  17. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  18. Model-based predictions for nuclear excitation functions of neutron-induced reactions on 64,66−68Zn targets

    Directory of Open Access Journals (Sweden)

    M. Yiğit

    2017-08-01

    Full Text Available In this paper, nuclear data for cross sections of the 64Zn(n,2n63Zn, 64Zn(n,3n62Zn, 64Zn(n,p64Cu, 66Zn(n,2n65Zn, 66Zn(n,p66Cu, 67Zn(n,p67Cu, 68Zn(n,p68Cu, and 68Zn(n,α65Ni reactions were studied for neutron energies up to 40 MeV. In the nuclear model calculations, TALYS 1.6, ALICE/ASH, and EMPIRE 3.2 codes were used. Furthermore, the nuclear data for the (n,2n and (n,p reaction channels were also calculated using various cross-section systematics at energies around 14–15 MeV. The code calculations were analyzed and obtained using the different level densities in the exciton model and the geometry-dependent hybrid model. The results obtained from the excitation function calculations are discussed and compared with literature experimental data, ENDF/B-VII.1, and the TENDL-2015 evaluated data.

  19. Analysis of the response of innovative neutron detectors with monoenergetic neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Romei, C.; Ciolini, R.; Mirzajani, N.; Selici, S. [Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione, Universita di Pisa, Pisa (Italy); Di Fulvio, A.; D' Errico, F. [Dipartimento di Ingegneria Meccanica, Nucleare e della Produzione, Universita di Pisa, Pisa (Italy); Yale University, New Haven, CT (United States); Souza, S. O. [Departamento de Fisica, Universidade Federal de Sergipe, Sao Cristovao (Brazil); Piotto, M. [Istituto di Ingegneria Elettronica, Computer e Telecomunicazioni, CNR, Pisa (Italy); Esposito, J.; Colautti, P. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy)

    2013-07-18

    Various neutron detectors are currently under development at the University of Pisa. The response of these devices is investigated using monoenergetic neutron beams produced at the CN accelerator of INFN Legnaro National Laboratories with thin lithium target bombarded by protons at different energies, exploiting the {sup 7}Li(p,n){sup 7}Be reaction.

  20. Neutron Therapy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutron Therapy Facility provides a moderate intensity, broad energy spectrum neutron beam that can be used for short term irradiations for radiobiology (cells)...

  1. Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.

    Science.gov (United States)

    Blue, Thomas E; Yanch, Jacquelyn C

    2003-01-01

    This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and

  2. Proton energy dependence of slow neutron intensity

    Energy Technology Data Exchange (ETDEWEB)

    Teshigawara, Makoto; Harada, Masahide; Watanabe, Noboru; Kai, Tetsuya; Sakata, Hideaki; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ooi, Motoki [Hokkaido Univ., Sapporo (Japan)

    2001-03-01

    The choice of the proton energy is an important issue for the design of an intense-pulsed-spallation source. The optimal proton beam energy is rather unique from a viewpoint of the leakage neutron intensity but no yet clear from the slow-neutron intensity view point. It also depends on an accelerator type. Since it is also important to know the proton energy dependence of slow-neutrons from the moderators in a realistic target-moderator-reflector assembly (TMRA). We studied on the TMRA proposed for Japan Spallation Neutron Source. The slow-neutron intensities from the moderators per unit proton beam power (MW) exhibit the maximum at about 1-2 GeV. At higher proton energies the intensity per MW goes down; at 3 and 50 GeV about 0.91 and 0.47 times as low as that at 1 GeV. The proton energy dependence of slow-neutron intensities was found to be almost the same as that of total neutron yield (leakage neutrons) from the same bare target. It was also found that proton energy dependence was almost the same for the coupled and decoupled moderators, regardless the different moderator type, geometry and coupling scheme. (author)

  3. 99 Tc靶件中子学特性及释热率特点的初步研究%Preliminary Study on the Neutronics and the Heat Releasing Rate Characteristics of 99 Tc Transmutation Target

    Institute of Scientific and Technical Information of China (English)

    贾晓淳; 于涛; 谢金森

    2015-01-01

    99 Tc是一种重要的长寿命裂变产物,半衰期长,极易随地下水迁徙扩散.将99 Tc嬗变为短寿命或稳定核素,可有效降低其对环境的危害.99 Tc在热中子谱下具有较大的吸收截面,采用PWR 嬗变99 Tc 是一种可行途径.为了评估99 Tc 嬗变靶件对PWR堆芯中子学参数的影响,并为含嬗变靶件的PWR组件热工水力计算提供数据,本文对含99 Tc的17×17 PWR组件进行模拟计算,给出了99 Tc靶件加入前后,燃料温度系数、慢化剂温度系数的变化规律;计算了稳态工况下99 Tc靶件的轴向释热率.相关结论可为PWR嬗变99 Tc研究提供参考.%99 Tc is a kind of important long-lived fission products with a very long half-life, which is easy to migrate with water underground. Transmuting 99 Tc to short life or stable nuclides will effectively reduce its harm to the environment. As 99 Tc has larger absorption cross section in the thermal neutron spectrum,it is a feasible way to transmute it in PWRs. In order to estimate the influence on the core neutronics parameters after putting the 99 Tc target into PWR,and to provide data for the thermal hydraulic calculation of PWR contai-ning targets, the article has caculated fuel temperature coefficient, moderator temperature coefficient before and after putting 99 Tc into a 17 × 17 PWR assembly and axial heat re-leasing rate of the 99 Tc target in steady state condition. The relevant conclusion can provide reference for the continued study of 99 Tc transmutation in PWR.

  4. The Muon-Induced Neutron Indirect-Detection EXperiment. MINIDEX

    Energy Technology Data Exchange (ETDEWEB)

    Palermo, Matteo

    2016-06-06

    A new experiment to measure muon-induced neutrons is introduced. The design of the Muon-Induced Neutron Indirect Detection EXperiment, MINIDEX, is presented and its installation and commissioning in the Tuebingen Shallow Underground Laboratory are described. Results from its first data taking period, run I, are presented. Muon-induced neutrons are not only an interesting physics topic by itself, but they are also an important source of background in searches for possible new rare phenomena like neutrinoless double beta decay or directly observable interactions of dark matter. These subjects are of great importance to understand the development of the early universe. Therefore, a new generation of ton-scale experiments which require extremely low background levels is under consideration. Reliable Monte Carlo simulations are needed to design such future experiments and estimate their background levels and sensitivities. The background due to muon-induced neutrons is hard to estimate, because of inconsistencies between different experimental results and discrepancies between measurements and Monte Carlo predictions. Especially for neutron production in high-Z materials, more experimental data and related simulation studies are clearly needed. MINIDEX addresses exactly this subject. Already the first five months of data taking provided valuable data on neutron production, propagation and interaction in lead. A first round of comparisons between MINIDEX data and Monte Carlo predictions are presented. In particular, the predictions of two Monte Carlo packages, based on GEANT4, are compared to the data. The data show an overall 70-100% higher rate of muon-induced events than predicted by the Monte Carlo packages. These packages also predict a faster time evolution of the muon-induced signal than observed in the data. Nevertheless, the time until the signal from the muon-induced events is completely collected was correctly predicted by the Monte Carlos. MINIDEX is foreseen

  5. Two neutron correlations in photo-fission

    Science.gov (United States)

    Dale, D. S.; Kosinov, O.; Forest, T.; Burggraf, J.; Stave, S.; Warren, G.; Starovoitova, V.

    2016-09-01

    A large body of experimental work has established the strong kinematical correlation between fission fragments and fission neutrons. Here, we report on the progress of investigations of the potential for strong two neutron correlations arising from the nearly back-to-back nature of the two fission fragments that emit these neutrons in the photo-fission process. In initial measurements, a pulsed electron linear accelerator was used to generate bremsstrahlung photons that impinged upon an actinide target, and the energy and opening angle distributions of coincident neutrons were measured using a large acceptance neutron detector array. A planned comprehensive set of measurements of two neutron correlations in the photo-fission of actinides is expected to shed light on several fundamental aspects of the fission process including the multiplicity distributions associated with the light and heavy fission fragments, the nuclear temperatures of the fission fragments, and the mass distribution of the fission fragments as a function of energy released. In addition to these measurements providing important nuclear data, the unique kinematics of fission and the resulting two neutron correlations have the potential to be the basis for a new tool to detect fissionable materials. A key technical challenge of this program arises from the need to perform coincidence measurements with a low duty factor, pulsed electron accelerator. This has motivated the construction of a large acceptance neutron detector array, and the development of data analysis techniques to directly measure uncorrelated two neutron backgrounds.

  6. Investigation of Space and Energy Distributions of Neutrons Generated in Lead Target and Uranium Blanket of the Electronuclear System "Energy plus Transmutation" under Irradiation with Protons at 1.5 GeV

    CERN Document Server

    Zhuk, I V; Krivopustov, M I; Sosnin, A N; Chultem, D; Vestmaer, V; Tumendelger, T; Zaveryukha, O S; Pavlyuk, A B

    2002-01-01

    The work contains the results of space-energy distributions of neutrons in U/Pb assembly, consisting of extended lead target and the model of natural uranium blanket irradiated with relativistic protons at 1.5 GeV. The research is carried out in the framework of a series of experiments using the model of subcritical heterogeneous electronuclear system at the Laboratory of High Energies, JINR, Dubna ("Investigation of Physical Aspects of Electronuclear Method of Energy Production and Transmutation of Radioactive Waste Using Beams from JINR Synchrophasotron/Nuclotron" - project "Energy plus Transmutation"). The results of measurements and calculations of ^{235}U, ^{238}U and ^{232}Th fission rate distributions as well as threshold spectral indexes {\\bar\\sigma_f^{^{232}Th}}/{\\bar\\sigma_f^{^{235}U}} and {\\bar\\sigma_f^{^{238}U}}/{\\bar\\sigma_f^{^{235}U}} along the radius of the target and model uranium blanket are presented. The results of measurements and calculations of ^{234}U, ^{236}U and ^{237}Np fission rate ...

  7. Experimental search for neutron - mirror neutron oscillations using storage of ultracold neutrons

    CERN Document Server

    Serebrov, A P; Dovator, N A; Dmitriev, S P; Fomin, A K; Geltenbort, P; Kharitonov, A G; Krasnoschekova, I A; Lasakov, M S; Murashkin, A N; Shmelev, G E; Varlamov, V E; Vassiljev, A V; Zherebtsov, O M; Zimmer, O

    2008-01-01

    The idea of a hidden sector of mirror partners of elementary particles has attracted considerable interest as a possible candidate for dark matter. Recently it was pointed out by Berezhiani and Bento that the present experimental data cannot exclude the possibility of a rapid oscillation of the neutron n to a mirror neutron n' with oscillation time much smaller than the neutron lifetime. A search for vacuum transitions n->n' has to be performed at weak magnetic field, where both states are degenerate. We report the result of our experiment, which compares rates of ultracold neutrons after storage at a weak magnetic field well below 20 nT and at a magnetic field strong enough to suppress the seeked transitions. We obtain a new limit for the oscillation time of n-n' transitions, tau_osc (90% C.L.) > 414 s. The corresponding limit for the mixing energy of the normal and mirror neutron states is delta_m (90% C.L.) < 1.5x10-18 eV.

  8. Experimental search for neutron mirror neutron oscillations using storage of ultracold neutrons

    Science.gov (United States)

    Serebrov, A. P.; Aleksandrov, E. B.; Dovator, N. A.; Dmitriev, S. P.; Fomin, A. K.; Geltenbort, P.; Kharitonov, A. G.; Krasnoschekova, I. A.; Lasakov, M. S.; Murashkin, A. N.; Shmelev, G. E.; Varlamov, V. E.; Vassiljev, A. V.; Zherebtsov, O. M.; Zimmer, O.

    2008-05-01

    The idea of a hidden sector of mirror partners of elementary particles has attracted considerable interest as a possible candidate for dark matter. Recently it was pointed out by Berezhiani and Bento that the present experimental data cannot exclude the possibility of a rapid oscillation of the neutron n to a mirror neutron n‧ with oscillation time much smaller than the neutron lifetime. A dedicated search for vacuum transitions n →n‧ has to be performed at weak magnetic field, where both states are degenerate. We report the result of our experiment, which compares rates of ultracold neutrons after storage at a weak magnetic field well below 20 nT and at a magnetic field strong enough to suppress the seeked transitions. We obtain a new limit for the oscillation time of n-n‧ transitions, τosc (90 % C.L.) > 414 s. The corresponding limit for the mixing energy of the normal and mirror neutron states is δm (90 % C.L.) < 1.5 ×10-18 eV.

  9. Segmented Target Design

    Science.gov (United States)

    Merhi, Abdul Rahman; Frank, Nathan; Gueye, Paul; Thoennessen, Michael; MoNA Collaboration

    2013-10-01

    A proposed segmented target would improve decay energy measurements of neutron-unbound nuclei. Experiments like this have been performed at the National Superconducting Cyclotron Laboratory (NSCL) located at Michigan State University. Many different nuclei are produced in such experiments, some of which immediately decay into a charged particle and neutron. The charged particles are bent by a large magnet and measured by a suite of charged particle detectors. The neutrons are measured by the Modular Neutron Array (MoNA) and Large Multi-Institutional Scintillation Array (LISA). With the current target setup, a nucleus in a neutron-unbound state is produced with a radioactive beam impinged upon a beryllium target. The resolution of these measurements is very dependent on the target thickness since the nuclear interaction point is unknown. In a segmented target using alternating layers of silicon detectors and Be-targets, the Be-target in which the nuclear reaction takes place would be determined. Thus the experimental resolution would improve. This poster will describe the improvement over the current target along with the status of the design. Work supported by Augustana College and the National Science Foundation grant #0969173.

  10. Measurement of accelerator neutron radiation field spectrum by Extended Range Neutron Multisphere Spectrometers and unfolding program

    CERN Document Server

    Li, Guanjia; Ma, Zhongjian; Guo, Siming; Yan, Mingyang; Shi, Haoyu; Xu, Chao

    2015-01-01

    This paper described a measurement of accelerator neutron radiation field at a transport beam line of Beijing-TBF. The experiment place was be selected around a Faraday Cup with a graphite target impacted by electron beam at 2.5GeV. First of all, we simulated the neutron radiation experiment by FLUKA. Secondly, we chose six appropriate ERNMS according to their neutron fluence response function to measure the neutron count rate. Then the U_M_G package program was be utilized to unfolding experiment data. Finally, we drew a comparison between the unfolding with the simulation spectrum and made an analysis about the result.

  11. Neutronics of a poisoned para-hydrogen moderator for a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Masahide [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan)]. E-mail: harada.masahide@jaea.go.jp; Watanabe, Noboru [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Teshigawara, Makoto [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Kai, Tetsuya [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Kato, Takashi [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan); Ikeda, Yujiro [Neutron Facility Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki-ken 319 1195 (Japan)

    2007-05-11

    Neutronic performance of a poisoned hydrogen moderator was studied in details. Using a simple rectangular-shape moderator-model, its basic characteristics were studied as a function of the poison position. We, for the first time, turned up that the pulse width was rather decreasing with increasing the moderator thickness of the back part from the poison. This is due to the fact that source neutron pulses entering into a front part of the poison through the back part exhibit a fast rise shape while those from the target and the reflector through the decoupler and liner exhibit a broad shape. Next, we studied the pulse deterioration in regard to a finite beam-extraction-angle by using a more realistic moderator shape, canteen shape and a concave-shape. It turns out that the pulse deterioration is considerably large in both cases even at a small extraction angle. The concave-shape moderator indicates a finite improvement compared to the canteen-shape one. Finally, merits and demerits of two poison materials, Cadmium and Gadolinium, were discussed taking into account the burn-up issue of poison with the operation time.

  12. Neutron scattering applications in structural biology: now and the future

    Energy Technology Data Exchange (ETDEWEB)

    Trewhella, J. [Los Alamos National Lab., NM (United States)

    1996-05-01

    Neutrons have an important role to play in structural biology. Neutron crystallography, small-angle neutron scattering and inelastic neutron scattering techniques all contribute unique information on biomolecular structures. In particular, solution scattering techniques give critical information on the conformations and dispositions of the components of complex assemblies under a wide variety of relevant conditions. The power of these methods is demonstrated here by studies of protein/DNA complexes, and Ca{sup 2+}-binding proteins complexed with their regulatory targets. In addition, we demonstrate the utility of a new structural approach using neutron resonance scattering. The impact of biological neutron scattering to date has been constrained principally by the available fluxes at neutron sources and the true potential of these approaches will only be realized with the development of new more powerful neutron sources. (author)

  13. Charge, neutron, and weak size of the atomic nucleus

    CERN Document Server

    Hagen, G; Forssén, C; Jansen, G R; Nazarewicz, W; Papenbrock, T; Wendt, K A; Bacca, S; Barnea, N; Carlsson, B; Drischler, C; Hebeler, K; Hjorth-Jensen, M; Miorelli, M; Orlandini, G; Schwenk, A; Simonis, J

    2015-01-01

    What is the size of the atomic nucleus? This deceivably simple question is difficult to answer. While the electric charge distributions in atomic nuclei were measured accurately already half a century ago, our knowledge of the distribution of neutrons is still deficient. In addition to constraining the size of atomic nuclei, the neutron distribution also impacts the number of nuclei that can exist and the size of neutron stars. We present an ab initio calculation of the neutron distribution of the neutron-rich nucleus $^{48}$Ca. We show that the neutron skin (difference between radii of neutron and proton distributions) is significantly smaller than previously thought. We also make predictions for the electric dipole polarizability and the weak form factor; both quantities are currently targeted by precision measurements. Based on ab initio results for $^{48}$Ca, we provide a constraint on the size of a neutron star.

  14. Measuring Neutron-Induced Reaction Cross Sections without Neutrons

    Science.gov (United States)

    Bernstein, L. A.; Schiller, A.; Cooper, J. R.; Hoffman, R. D.; McMahan, M. A.; Fallon, P.; Macchiavelli, A. O.; Mitchell, G.; Tavukcu, E.; Guttormsen, M.

    2003-04-01

    Neutron-induced reactions on radioactive nuclei play a significant role in nuclear astrophysics and many other applied nuclear physics topics. However, the majority of these cross sections are impossible to measure due to the high-background of the targets and the low-intensity of neutron beams. We have explored the possibility of using charged-particle transfer reactions to form the same "pre-compound" nucleus as one formed in a neutron-induced reaction in order to measure the relative decay probabilities of the nucleus as a function of energy. Multiplying these decay probabilities by the neutron absorption cross section will then produce the equivalent neutron-induced reaction cross section. In this presentation I will explore the validity of this "surrogate reaction" technique by comparing results from the recent 157Gd(3He,axng)156-xGd experiment using STARS (Silicon Telescope Array for Reaction Studies) at GAMMASPHERE with reaction model calculations for the 155Gd(n,xng)156-xGd. This work was funded by the US Department of Energy under contracts number W-7405-ENG-48 (LLNL), AC03-76SF00098 (LBNL) and the Norwegian Research Council (Oslo).

  15. Plasma driven neutron/gamma generator

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Ka-Ngo; Antolak, Arlyn

    2015-03-03

    An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

  16. The detection of neutron clusters

    Energy Technology Data Exchange (ETDEWEB)

    Marques, F.M.; Labiche, M.; Orr, N.A.; Angelique, J.C. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire] [and others

    2001-11-01

    A new approach to the production and detection of bound neutron clusters is presented. The technique is based on the breakup of beams of very neutron-rich nuclei and the subsequent detection of the recoiling proton in a liquid scintillator. The method has been tested in the breakup of {sup 11}Li, {sup 14}Be and {sup 15}B beams by a C target. Some 6 events were observed that exhibit the characteristics of a multi-neutron cluster liberated in the breakup of {sup 14}Be, most probably in the channel {sup 10}Be+{sup 4}n. The various backgrounds that may mimic such a signal are discussed in detail. (author)

  17. Conceptual design of an RFQ accelerator-based neutron source for boron neutron-capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wangler, T.P.; Stovall, J.E.; Bhatia, T.S.; Wang, C.K.; Blue, T.E.; Gahbauer, R.A.

    1989-01-01

    We present a conceptual design of a low-energy neutron generator for treatment of brain tumors by boron neutron capture theory (BNCT). The concept is based on a 2.5-MeV proton beam from a radio-frequency quadrupole (RFQ) linac, and the neutrons are produced by the /sup 7/Li(p,n)/sup 7/Be reaction. A liquid lithium target and modulator assembly are designed to provide a high flux of epithermal neutrons. The patient is administered a tumor-specific /sup 10/Be-enriched compound and is irradiated by the neutrons to create a highly localized dose from the reaction /sup 10/B(n,..cap alpha..)/sup 7/Li. An RFQ accelerator-based neutron source for BNCT is compact, which makes it practical to site the facility within a hospital. 11 refs., 5 figs., 1 tab.

  18. Study on neutron beam probe. Study on the focused neutron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kotajima, Kyuya; Suzuki, K.; Fujisawa, M.; Takahashi, T.; Sakamoto, I. [Tohoku Univ., Sendai (Japan). Faculty of Engineering; Wakabayashi, T.

    1998-03-01

    A monoenergetic focused neutron beam has been produced by utilizing the endoenergetic heavy ion reactions on hydrogen. To realize this, the projectile heavy ion energy should be taken slightly above the threshold energy, so that the excess energy converted to the neutron energy should be very small. In order to improve the capability of the focused neutron beam, some hydrogen stored metal targets have also been tested. Separating the secondary heavy ions (associated particles) from the primary ions (accelerated particles) by using a dipole magnet, a rf separator, and a particle identification system, we could directly count the produced neutrons. This will leads us to the possibility of realizing the standard neutron field which had been the empty dream of many neutron-related researchers in the world. (author)

  19. Self-shielding effects in neutron spectra measurements for neutron capture therapy by means of activation foils.

    Science.gov (United States)

    Pytel, Krzysztof; Józefowicz, Krystyna; Pytel, Beatrycze; Koziel, Alina

    2004-01-01

    The design and optimisation of a neutron beam for neutron capture therapy (NCT) is accompanied by the neutron spectra measurements at the target position. The method of activation detectors was applied for the neutron spectra measurements. Epithermal neutron energy region imposes the resonance structure of activation cross sections resulting in strong self-shielding effects. The neutron self-shielding correction factor was calculated using a simple analytical model of a single absorption event. Such a procedure has been applied to individual cross sections from pointwise ENDF/B-VI library and new corrected activation cross sections were introduced to a spectra unfolding algorithm. The method has been verified experimentally both for isotropic and for parallel neutron beams. Two sets of diluted and non-diluted activation foils covered with cadmium were irradiated in the neutron field. The comparison of activation rates of diluted and non-diluted foils has demonstrated the correctness of the applied self-shielding model.

  20. The “neutron channel design”—A method for gaining the desired neutrons

    Directory of Open Access Journals (Sweden)

    G. Hu

    2016-12-01

    Full Text Available The neutrons with desired parameters can be obtained after initial neutrons penetrating various structure and component of the material. A novel method, the “neutron channel design”, is proposed in this investigation for gaining the desired neutrons. It is established by employing genetic algorithm (GA combining with Monte Carlo software. This method is verified by obtaining 0.01eV to 1.0eV neutrons from the Compact Accelerator-driven Neutron Source (CANS. One layer polyethylene (PE moderator was designed and installed behind the beryllium target in CANS. The simulations and the experiment for detection the neutrons were carried out. The neutron spectrum at 500cm from the PE moderator was simulated by MCNP and PHITS software. The counts of 0.01eV to 1.0eV neutrons were simulated by MCNP and detected by the thermal neutron detector in the experiment. These data were compared and analyzed. Then this method is researched on designing the complex structure of PE and the composite material consisting of PE, lead and zirconium dioxide.

  1. Boron neutron capture therapy of EGFR or EGFRvIII positive gliomas using either boronated monoclonal antibodies or epidermal growth factor as molecular targeting agents

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W. [Department of Pathology, Ohio State University, 165 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210 (United States); Barth, R.F. [Department of Pathology, Ohio State University, 165 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210 (United States)], E-mail: rolf.barth@osumc.edu; Wu, G. [Department of Pathology, Ohio State University, 165 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210 (United States); Tjarks, W. [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States); Binns, P.; Riley, K. [Nuclear Reactor Laboratory and Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02215 (United States)

    2009-07-15

    In the present report we have summarized studies carried out over the past five years on molecular targeting of the epidermal growth factor receptor (EGFR) and its mutant isoform, EFGRvIII, for BNCT of genetically engineered F98 rat gliomas, expressing either wildtype (F98{sub EGFR}) or mutant receptors (F98{sub npEGFRvIII}). EGF or the monoclonal antibodies (mAbs), cetuximab (IMC-C225) and L8A4, which recognize wildtype EGFR and EGFRvIII, respectively, were heavily boronated using polyamidoamine (PAMAM) dendrimers (BD) linked to the targeting vehicles by means of heterobifunctional reagents. Boronated EGF or mAbs, alone or in combination with i.v. boronophenylalanine (BPA), were administered intracerebrally (i.c.) by either intratumoral (i.t.) injection or convection enhanced delivery (CED) to rats bearing F98 gliomas following which BNCT was initiated. The best survival data were obtained in rats bearing F98{sub npEGFRvIII} gliomas that had received CED of BD-L8A4 either alone or in combination with i.v. boronophenylalanine (BPA). Studies carried out in rats bearing composite tumors (F98{sub EGFR}/F98{sub npEGFRvIII}) demonstrated that it was essential to target both tumor cell populations in order to obtain an optimal therapeutic effect. Based on these observations, we have concluded that EGFR targeting vehicles are useful, but not stand-alone boron delivery agents due to the heterogeneity of receptor expression in brain tumors. They could, however, be quite useful in combination with the two drugs that currently are being used clinically, BPA and sodium borocaptate (BSH) for BNCT of either brain tumors or head and neck cancers.

  2. Neutron Capture Experiments on Unstable Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Jon M. Schwantes; Ralf Sudowe; Heino Nitsche; Darleane C. Hoffman

    2003-12-16

    A primary objective of this project is to study neutron capture cross sections for various stable and unstable isotopes that will contribute to the Science Based Stockpile Stewardship (SBSS) program by providing improved data for modeling and interpretation of nuclear device performance. The information obtained will also be important in astrophysical modeling of nucleosynthesis. During this reporting period, the emphasis has been on preparing a radioactive target of {sup 155}Eu (half-life = 4.7 years), and several stable targets, including isotopically separated {sup 154}Sm, {sup 151}Eu, and {sup 153}Eu. Measurements of their neutron capture cross sections will be conducted in collaboration with researchers at the Los Alamos Neutron Science Center (LANSCE) facility using the Detector for Advanced Neutron Capture Experiments (DANCE). A suitable backing material (beryllium) for the targets has been selected after careful calculations of its contribution to the background of the measurements. In addition, a high voltage plating procedure has been developed and optimized. Stable targets of {sup 151}Eu and {sup 153}Eu and a target of natural Eu ({approx}50% {sup 151}Eu and {approx}50% {sup 153}Eu) have each been plated to a mass thickness of >1 mg/cm{sup 2} and delivered to the DANCE collaboration at Los Alamos National Laboratory (LANL). Natural Eu targets will be tested first to confirm that the target dimensions and backing are appropriate prior to performing measurements on the extremely valuable targets of separated isotopes. In order to prepare a target of the radioactive {sup 155}Eu, it must first be separated from the {sup 154}Sm target material that was irradiated in a very high neutron flux of 1.5x1015 neutrons/cm{sup 2}/s for 50 days. The reaction is {sup 154}Sm (n,f){sup 155}Sm (half-life = 22 minutes) {sup 155}Eu. Considerable progress has been made in developing a suitable high-yield and high-purity separation method for separating Eu from targets

  3. Neutron and X-ray Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Carini, Gabriella [SLAC National Accelerator Lab., Menlo Park, CA (United States); Denes, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gruener, Sol [Cornell Univ., Ithaca, NY (United States); Lessner, Elianne [Dept. of Energy (DOE), Washington DC (United States). Office of Science Office of Basic Energy Sciences

    2012-08-01

    The Basic Energy Sciences (BES) X-ray and neutron user facilities attract more than 12,000 researchers each year to perform cutting-edge science at these state-of-the-art sources. While impressive breakthroughs in X-ray and neutron sources give us the powerful illumination needed to peer into the nano- to mesoscale world, a stumbling block continues to be the distinct lag in detector development, which is slowing progress toward data collection and analysis. Urgently needed detector improvements would reveal chemical composition and bonding in 3-D and in real time, allow researchers to watch “movies” of essential life processes as they happen, and make much more efficient use of every X-ray and neutron produced by the source The immense scientific potential that will come from better detectors has triggered worldwide activity in this area. Europe in particular has made impressive strides, outpacing the United States on several fronts. Maintaining a vital U.S. leadership in this key research endeavor will require targeted investments in detector R&D and infrastructure. To clarify the gap between detector development and source advances, and to identify opportunities to maximize the scientific impact of BES user facilities, a workshop on Neutron and X-ray Detectors was held August 1-3, 2012, in Gaithersburg, Maryland. Participants from universities, national laboratories, and commercial organizations from the United States and around the globe participated in plenary sessions, breakout groups, and joint open-discussion summary sessions. Sources have become immensely more powerful and are now brighter (more particles focused onto the sample per second) and more precise (higher spatial, spectral, and temporal resolution). To fully utilize these source advances, detectors must become faster, more efficient, and more discriminating. In supporting the mission of today’s cutting-edge neutron and X-ray sources, the workshop identified six detector research challenges

  4. Neutron Science Project at JAERI

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Japan Atomic Energy Research Institute, JAERI, is proposing the Neutron Science Project which aims at bringing about scientific and technological innovation in the fields of basic science and nuclear technology for the 21st century, using high intense spallation neutron source. The research areas to be promoted by the project are neutron structural biology, material science, nuclear physics and various technology developments for accelerator-driven transmutation of long-lived radionuclides which are associated with nuclear power generation. JAERI has been carrying out a R and D program for the partitioning and transmutation with the intention to solve the problem of nuclear fuel cycle backend. The accelerator-driven transmutation study is also covered with this program. In the present stage of the project, a conceptual design is being prepared for a research complex utilizing spallation neutrons, including a high intensity pulsed and steady spallation neutron source with 1.5 GeV and 8 MW superconducting proton linac. The idea and facility plan of the project is described, including the status of technological development of the accelerator, target and facilities. (author)

  5. An Accelerator Neutron Source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Blue, Thomas, E

    2006-03-14

    The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.

  6. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  7. Neutron Capture Reactions on lu Isotopes at Dance

    Science.gov (United States)

    Roig, O.; Meot, V.; Daugas, J.-M.; Morel, P.; Jandel, M.; Vieira, D. J.; Bond, E. M.; Bredeweg, T. A.; Couture, A. J.; Haight, R. C.; Keksis, A. L.; Rundberg, R. S.; Ullmann, J. L.; Wouters, J. M.

    2013-03-01

    The DANCE1 (Detector for Advanced Neutron Capture Experiments) array at LANSCE spallation neutron source in Los Alamos has been used to obtain the neutron radiative capture cross sections for 175Lu and 176Lu with neutron energies from thermal up to 100 keV. Both isotopes are of current interest for the nucleosynthesis s-process.2,3 Three targets were used to perform these measurements. One was natural Lu foil of 31 mg/cm2 and the other two were isotope-enriched targets of 175Lu and 176Lu. Firstly, the cross sections were obtained by normalizing yield to a well-known cross section at the thermal neutron energy. Now, we want to obtain absolute cross sections of radiative capture through a precise neutron flux determination, an accurate target mass measurement and an efficiency determination of the DANCE array.

  8. Status of the Neutron Imaging and Diffraction Instrument IMAT

    Science.gov (United States)

    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.

  9. Detection of special nuclear material by observation of delayed neutrons with a novel fast neutron composite detector

    Science.gov (United States)

    Mayer, Michael; Nattress, Jason; Barhoumi Meddeb, Amira; Foster, Albert; Trivelpiece, Cory; Rose, Paul; Erickson, Anna; Ounaies, Zoubeida; Jovanovic, Igor

    2015-10-01

    Detection of shielded special nuclear material is crucial to countering nuclear terrorism and proliferation, but its detection is challenging. By observing the emission of delayed neutrons, which is a unique signature of nuclear fission, the presence of nuclear material can be inferred. We report on the observation of delayed neutrons from natural uranium by using monoenergetic photons and neutrons to induce fission. An interrogating beam of 4.4 MeV and 15.1 MeV gamma-rays and neutrons was produced using the 11B(d,n-γ)12C reaction and used to probe different targets. Neutron detectors with complementary Cherenkov detectors then discriminate material undergoing fission. A Li-doped glass-polymer composite neutron detector was used, which displays excellent n/ γ discrimination even at low energies, to observe delayed neutrons from uranium fission. Delayed neutrons have relatively low energies (~0.5 MeV) compared to prompt neutrons, which makes them difficult to detect using recoil-based detectors. Neutrons were counted and timed after the beam was turned off to observe the characteristic decaying time profile of delayed neutrons. The expected decay of neutron emission rate is in agreement with the common parametrization into six delayed neutron groups.

  10. Fast neutron environments.

    Energy Technology Data Exchange (ETDEWEB)

    Buchheit, Thomas Edward; Kotula, Paul Gabriel; Lu, Ping; Brewer, Luke N. (Naval Postgraduate School, Monterey, CA); Goods, Steven Howard (Sandia National Laboratories, Livermore, CA); Foiles, Stephen Martin; Puskar, Joseph David; Hattar, Khalid Mikhiel; Doyle, Barney Lee; Boyce, Brad Lee; Clark, Blythe G.

    2011-10-01

    The goal of this LDRD project is to develop a rapid first-order experimental procedure for the testing of advanced cladding materials that may be considered for generation IV nuclear reactors. In order to investigate this, a technique was developed to expose the coupons of potential materials to high displacement damage at elevated temperatures to simulate the neutron environment expected in Generation IV reactors. This was completed through a high temperature high-energy heavy-ion implantation. The mechanical properties of the ion irradiated region were tested by either micropillar compression or nanoindentation to determine the local properties, as a function of the implantation dose and exposure temperature. In order to directly compare the microstructural evolution and property degradation from the accelerated testing and classical neutron testing, 316L, 409, and 420 stainless steels were tested. In addition, two sets of diffusion couples from 316L and HT9 stainless steels with various refractory metals. This study has shown that if the ion irradiation size scale is taken into consideration when developing and analyzing the mechanical property data, significant insight into the structural properties of the potential cladding materials can be gained in about a week.

  11. Neutron Capture Nucleosynthesis

    CERN Document Server

    Kiss, Miklos

    2016-01-01

    Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

  12. Nuclear reactor neutron shielding

    Energy Technology Data Exchange (ETDEWEB)

    Speaker, Daniel P; Neeley, Gary W; Inman, James B

    2017-09-12

    A nuclear reactor includes a reactor pressure vessel and a nuclear reactor core comprising fissile material disposed in a lower portion of the reactor pressure vessel. The lower portion of the reactor pressure vessel is disposed in a reactor cavity. An annular neutron stop is located at an elevation above the uppermost elevation of the nuclear reactor core. The annular neutron stop comprises neutron absorbing material filling an annular gap between the reactor pressure vessel and the wall of the reactor cavity. The annular neutron stop may comprise an outer neutron stop ring attached to the wall of the reactor cavity, and an inner neutron stop ring attached to the reactor pressure vessel. An excore instrument guide tube penetrates through the annular neutron stop, and a neutron plug comprising neutron absorbing material is disposed in the tube at the penetration through the neutron stop.

  13. Redesign of the Target-Moderator-Reflector-Shield Assembly for Optimization of the Neutron Flux in the 0.001 – 1 MeV at LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Nowicki, Suzanne Florence [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wender, Stephen Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ferres, Laurent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-10

    These are the slides for a presentation at the 2016 Postdoc Summer Seminar Series at Los Alamos National Laboratory. The conclusions of the research presented are the following: we can provide a significant gain in intensity in the upper tier; lower and upper tier are coupled: translating the target in the FOV of the upper tier decreases the intensity in the lower tier; it is possible to balance the production between the upper and lower tier if we keep some of the material between the tiers.

  14. Design of low-energy neutron beams for boron neutron capture synovectomy

    Science.gov (United States)

    Yanch, Jacquelyn C.; Shefer, Ruth E.; Binello, E.

    1997-02-01

    A novel application of the 10B(n, (alpha) )7Li nuclear reaction for the treatment of rheumatoid arthritis is under development. this application, called Boron Neutron Capture Synovectomy (BNCS), is briefly described here and the differences between BNCS and Boron Neutron Capture Therapy (BNCT) are discussed in detail. These differences lead to substantially altered demands on neutron beam design for each therapy application. In this paper the considerations for neutron beam design for the treatment of arthritic joints via BNCS are discussed, and comparisons with the design requirements for BNCT are made. This is followed by a description of potential moderator/reflector assemblies that are calculated to produce intense, high- quality neutron beams based on the 7Li(p,n) accelerator- based reactions. Total therapy time and therapeutic ratios are given as a function of both moderator length and boron concentration. Finally, a means of carrying out multi- directional irradiations of arthritic joints is proposed.

  15. Weapons Neutron Research Facility (WNR)

    Data.gov (United States)

    Federal Laboratory Consortium — The Weapons Neutron Research Facility (WNR) provides neutron and proton beams for basic, applied, and defense-related research. Neutron beams with energies ranging...

  16. Narcotics detection using fast-neutron interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Micklich, B.J.; Fink, C.L.

    1995-12-31

    Fast-neutron interrogation techniques are being investigated for detection of narcotics in luggage and cargo containers. This paper discusses two different fast-neutron techniques. The first uses a pulsed accelerator or sealed-tube source to produce monoenergetic fast neutrons. Gamma rays characteristic of carbon and oxygen are detected and the elemental densities determined. Spatial localization is accomplished by either time of flight or collimators. This technique is suitable for examination of large containers because of the good penetration of the fast neutrons and the low attenuation of the high-energy gamma rays. The second technique uses an accelerator to produce nanosecond pulsed beams of deuterons that strike a target to produce a pulsed beam of neutrons with a continuum of energies. Elemental distributions are obtained by measuring the neutron spectrum after the source neutrons pass through the items being interrogated. Spatial variation of elemental densities is obtained by tomographic reconstruction of projection data obtained for three to five angles and relatively low (2 cm) resolution. This technique is best suited for examination of luggage or small containers with average neutron transmissions greater than about 0.01. Analytic and Monte-Carlo models are being used to investigate the operational characteristics and limitations of both techniques.

  17. Observation of resonant lattice modes by inelastic neutron scattering

    DEFF Research Database (Denmark)

    Bjerrum Møller, Hans; Mackintosh, A.R.

    1965-01-01

    Observation by inelastic neutron scattering of resonant lattice modes due to small concentration of W atoms in Cr host crystal; frequencies and lifetimes of phonons with frequencies near that of resonant mode are considerably affected by presence of defects....

  18. Determination of spallation neutron flux through spectral adjustment techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, M.A., E-mail: mosbym@lanl.gov; Engle, J.W.; Jackman, K.R.; Nortier, F.M.; Birnbaum, E.R.

    2016-08-15

    The Los Alamos Isotope Production Facility (IPF) creates medical isotopes using a proton beam impinged on a target stack. Spallation neutrons are created in the interaction of the beam with target. The use of these spallation neutrons to produce additional radionuclides has been proposed. However, the energy distribution and magnitude of the flux is not well understood. A modified SAND-II spectral adjustment routine has been used with radioactivation foils to determine the differential neutron fluence for these spallation neutrons during a standard IPF production run.

  19. Determination of spallation neutron flux through spectral adjustment techniques

    Science.gov (United States)

    Mosby, M. A.; Engle, J. W.; Jackman, K. R.; Nortier, F. M.; Birnbaum, E. R.

    2016-08-01

    The Los Alamos Isotope Production Facility (IPF) creates medical isotopes using a proton beam impinged on a target stack. Spallation neutrons are created in the interaction of the beam with target. The use of these spallation neutrons to produce additional radionuclides has been proposed. However, the energy distribution and magnitude of the flux is not well understood. A modified SAND-II spectral adjustment routine has been used with radioactivation foils to determine the differential neutron fluence for these spallation neutrons during a standard IPF production run.

  20. Antiproton radiotherapy: peripheral dose from secondary neutrons

    DEFF Research Database (Denmark)

    Fahimian, Benjamin P.; DeMarco, John J.; Keyes, Roy

    2009-01-01

    is the normal tissue dose resulting from secondary neutrons produced in the annihilation of antiprotons on the nucleons of the target atoms. Here we present the first organ specific Monte Carlo calculations of normal tissue equivalent neutron dose in antiproton therapy through the use of a segmented CT......-based human phantom. The MCNPX Monte Carlo code was employed to quantify the peripheral dose for a cylindrical spread out Bragg peak representing a treatment volume of 1 cm diameter and 1 cm length in the frontal lobe of a segmented whole-body phantom of a 38 year old male. The secondary neutron organ dose...

  1. Neutron beams from protons on beryllium.

    Science.gov (United States)

    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.

  2. On the use of the (π-,K0) reaction on nuclear targets for the precise determination of the lifetime of the hydrogen hyperisotopes and other neutron-rich Λ-hypernuclei

    Science.gov (United States)

    Agnello, M.; Botta, E.; Bressani, T.; Bufalino, S.; Feliciello, A.

    2016-10-01

    Recent results reported by experiments with relativistic (heavy) ions have raised again the question whether the lifetime of H3Λ is very close to the lifetime of the free Λ hyperon. An updated careful analysis of all the existing experimental data shows that it is not, contrary to theoretical calculations. A similar conclusion can be drawn for the neighbor H4Λ. A clear cut high precision measurement performed with the straightforward method of time delay spectra is however lacking and it is eagerly needed. The idea of using the (π- ,K0) charge-exchange associated production reaction on targets of liquid 3,4He is discussed. A possible realization exploiting a large part of existing facilities at J-PARC is presented. A measurement with a 5% precision seems within reach with a modest effort and in a reasonable amount of time. The same set-up would also serve very well for the measurement of the lifetime of several neutron-rich Λ-hypernuclei of the p-shell, in particular of B12Λ. More importantly, the Weak Decay partial widths Γπ-, Γp and Γπ0 could be simultaneously determined in order to confirm their predicted strong variation with mass number, A, due to nuclear structure effects.

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

    Science.gov (United States)

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

    2011-09-01

    define the design of the moderator in the inlet of the radiation channel. A graphite block of 22 cm thickness seems to be the optimal neutron moderator. The results showed that the combination of 5 cm of bismuth with 5 cm of sapphire permits the filtration of gamma-rays, epithermal neutrons as well as fast neutrons in a considerable way without affecting the neutron thermal flux.

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

    CERN Document Server

    Arimoto, Y; Igarashi, Y; Iwashita, Y; Ino, T; Katayama, R; Kitahara, R; Kitaguchi, M; Matsumura, H; Mishima, K; 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; Yamada, T; Yamashita, S; Yokoyama, H; Yoshioka, T

    2015-01-01

    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 $^6$Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

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

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto, Y. [High Energy Accelerator Research Organization, Ibaraki (Japan); Higashi, N. [Graduate School of Science, University of Tokyo, Tokyo (Japan); Igarashi, Y. [High Energy Accelerator Research Organization, Ibaraki (Japan); Iwashita, Y. [Institute for Chemical Research, Kyoto University, Kyoto (Japan); Ino, T. [High Energy Accelerator Research Organization, Ibaraki (Japan); Katayama, R. [Graduate School of Science, University of Tokyo, Tokyo (Japan); Kitaguchi, M. [Kobayashi-Maskawa Institute, Nagoya University, Aichi (Japan); Kitahara, R. [Graduate School of Science, Kyoto University, Kyoto (Japan); Matsumura, H.; Mishima, K. [High Energy Accelerator Research Organization, Ibaraki (Japan); Nagakura, N.; Oide, H. [Graduate School of Science, University of Tokyo, Tokyo (Japan); Otono, H., E-mail: otono@phys.kyushu-u.ac.jp [Research Centre for Advanced Particle Physics, Kyushu University, Fukuoka (Japan); Sakakibara, R. [Department of Physics, Nagoya University, Aichi (Japan); Shima, T. [Research Center for Nuclear Physics, Osaka University, Osaka (Japan); Shimizu, H.M.; Sugino, T. [Department of Physics, Nagoya University, Aichi (Japan); Sumi, N. [Faculty of Sciences, Kyushu University, Fukuoka (Japan); Sumino, H. [Department of Basic Science, University of Tokyo, Tokyo (Japan); Taketani, K. [High Energy Accelerator Research Organization, Ibaraki (Japan); and others

    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 {sup 6}Li-enriched tiles to absorb outlier neutrons. In this paper, the design and performance of the new TPC are reported in detail.

  6. Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE

    Science.gov (United States)

    Jandel, M.; Bredeweg, T. A.; Stoyer, M. A.; Wu, C. Y.; Fowler, M. M.; Becker, J. A.; Bond, E. M.; Couture, A.; Haight, R. C.; Haslett, R. J.; Henderson, R. A.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.

    2009-01-01

    Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for 241Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for 243Am for neutron energies between 10 eV and 250 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on 242mAm will be presented where the fission events were actively triggered during the experiments. In these experiments, a Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,γ) events from (n,f) events. The first direct observation of neutron capture on 242mAm in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

  7. Neutron spectrum unfolding using radial basis function neural networks.

    Science.gov (United States)

    Alvar, Amin Asgharzadeh; Deevband, Mohammad Reza; Ashtiyani, Meghdad

    2017-07-26

    Neutron energy spectrum unfolding has been the subject of research for several years. The Bayesian theory, Monte Carlo simulation, and iterative methods are some of the methods that have been used for neutron spectrum unfolding. In this study, the radial basis function (RBF), multilayer perceptron, and artificial neural networks (ANNs) were used for the unfolding of neutron spectrum, and a comparison was made between the networks' results. Both neural network architectures were trained and tested using the same data set for neutron spectrum unfolding from the response of LiI detectors with Eu impurity. Advantages of each ANN method in the unfolding of neutron energy spectrum were investigated, and the performance of the networks was compared. The results obtained showed that RBF neural network can be applied as an effective method for unfolding neutron spectrum, especially when the main target is the neutron dosimetry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Superheated drop neutron spectrometer

    CERN Document Server

    Das, M; Roy, B; Roy, S C; Das, Mala

    2000-01-01

    Superheated drops are known to detect neutrons through the nucleation caused by the recoil nuclei produced by the interactions of neutrons with the atoms constituting the superheated liquid molecule. A novel method of finding the neutron energy from the temperature dependence response of SDD has been developed. From the equivalence between the dependence of threshold energy for nucleation on temperature of SDD and the dependence of dE/dx of the recoil ions with the energy of the neutron, a new method of finding the neutron energy spectrum of a polychromatic as well as monochromatic neutron source has been developed.

  9. Neutron streak camera

    Science.gov (United States)

    Wang, Ching L.

    1983-09-13

    Apparatus for improved sensitivity and time resolution of a neutron measurement. The detector is provided with an electrode assembly having a neutron sensitive cathode which emits relatively low energy secondary electrons. The neutron sensitive cathode has a large surface area which provides increased sensitivity by intercepting a greater number of neutrons. The cathode is also curved to compensate for differences in transit time of the neutrons emanating from the point source. The slower speeds of the secondary electrons emitted from a certain portion of the cathode are matched to the transit times of the neutrons impinging thereupon.

  10. Exclusive pi- Electroproduction off the Neutron in Deuterium in the Resonance Region

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Ye [Univ. of South Carolina, Columbia, SC (United States); Gothe, Ralf W. [Univ. of South Carolina, Columbia, SC (United States)

    2016-03-01

    The goal of our research is to provide the exclusive γ*(n) → p+π− reaction cross section from deuterium data using the correction factor that account for the final state re-scattering that can be determined from the data set itself. The “e1e” Jefferson Lab CLAS data set that we analyze includes both a hydrogen and deuterium target run period, which allows a combined analysis of pion electroproduction off the free proton, the bound proton, and the bound neutron under the same experimental conditions. Hence it will provide the experimentally best possible information about the off-shell and final state interaction effects in deuterium, which must be considered in order to extract the neutron information. This data set will provide results with a kinematic coverage for the hadronic invariant mass W up to 1.7 GeV and in the momentum transfer Q2 range of 0.4 − 1.0 GeV/c2. The cross section analysis of this data set is currently underway, which will considerably improve our knowledge of the Q2 evolution of π−p electroproduction cross sections off bound neutron needed for the extraction of excited neutron state electrocouplings for the first time.

  11. Development and modelling of fission chambers designed for high neutron fluxes: applications at the HFR reactor (ILL) and the MEGAPIE target (PSI); Developpement et modelisation de chambres a fission pour les hauts flux, mise en application au RHF (ILL) et a MEGAPIE (PSI)

    Energy Technology Data Exchange (ETDEWEB)

    Chabod, S

    2006-11-15

    The international project MEGAPIE (MEGAwatt PIlot Experiment) at the Paul Scherrer Institute aims to build and operate the first 1 MW liquid lead-bismuth spallation target. This work is dedicated to the characterization of the neutron flux and the actinide incineration potential of the target. This mission has required the development of an innovating neutron detector (DNM) made of 8 micro fission chambers, installed inside the central rod of the MEGAPIE target. The combination of uranium chambers with chambers without deposit allows an efficient compensation of the gamma radiation background. The optimisation and development work on the MEGAPIE chambers have enabled us to measure the {sigma}{sub f} * {phi} product at each level of the DNM with an uncertainty of less than 3 per cent. We have inferred from these data the value of the epithermal neutron flux (E > 1 eV) at 37 cm away from the window: 3.4*10{sup 13} n.cm{sup -2}.s{sup -1}, and the values of the neutron flux at 50, 60 and 74 cm: 1.2*10{sup 13}, 7.9*10{sup 12} and 3.9*10{sup 12} n.cm{sup -2}.s{sup -1} respectively. All these values are notably less important than those obtained from MCNPX simulations. Thermocouples installed in DMN have enabled us to know the temperature distribution inside the target. For a beam intensity of 1.2 mA, the temperature ranges from 360 to 420 Celsius degrees in the low part of the central rod. The thermal inertia of the system composed of the central rod and DNM has been assessed for brutal changes of the beam intensity and is worth about 60 s. (A.C.)

  12. Neutrons production on the IPHI accelerator for the validation of the design of the compact neutron source SONATE

    CERN Document Server

    Menelle, Alain; Prunes, Fabien; Homatter, Benoit; Annighöfer, Burkhard; Porcher, Florence; Chauvin, Nicolas; Schwindling, Jérôme; Letourneau, Alain; Marchix, Anthony; Tran, Ngoc-Hoang

    2016-01-01

    We aim at building an accelerator based compact neutron source which would provide a thermal neutron flux on the order of 4E12 n.s-1.cm-2.sr-1. Such brilliance would put compact neutron sources on par with existing medium flux neutron research reactors. We performed the first neutron production tests on the IPHI proton accelerator at Saclay. The neutron fluxes were measured using gold foil activation and 3He detectors. The measured fluxes were compared with MCNP and GEANT4 Monte Carlo simulations in which the whole experimental setup was modelled. There is a good agreement between the experimental measurements and the Monte-Carlo simulations. The available modelling tools will allow us to optimize the whole Target Moderator Reflector assembly together with the neutron scattering spectrometer geometries.

  13. A preliminary area survey of neutron radiation levels associated with the NASA variable energy cyclotron horizontal neutron delivery system

    Science.gov (United States)

    Roberts, W. K.; Leonard, R. F.

    1976-01-01

    The 25 MeV deuteron beam from the NASA variable energy cyclotron incident on a thick beryllium target will deliver a tissue neutron dose rate of 2.14 rad micron A-min at a source to skin distance of 125 cm. A neutron survey of the existing hallways with various shielding configurations made during operating of the horizontal neutron delivery system indicates that minimal amounts of additional neutron shielding material are required to provide a low level radiation environment within a self-contained neutron therapy control station. Measurements also indicate that the primary neutron distribution delivered by a planned vertical delivery system will be minimally perturbed by neutrons backscattered from the floor.

  14. Simulation of a Compact Neutron Source with 13MeV Cyclotron

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong ho; Lee, Seung Wook [Pusan National University, Busan (Korea, Republic of); Moon, Myung Kook; Hur, Min Goo; Kim, GTae Joo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In this presentation, we calculated neutron flux and neutron energy spectrum in 13MeV Cyclotron. Additionally, we found suitable design of target, metal layer and cooling system. We could find an opportunity about neutron radiography system by using cyclotron. For neutron radiography, fast neutron have to shift thermal range. We need to study this direction. Monte Carlo code is not almighty, so we need to refer to this data. This presentation can be first step to prove to operate KIRAMS-13 in Pusan National University. Proton accelerator is valuable for neutron generator for neutron generator. This paper is aim to verify possibility to get neutron from KIRAMS-13, which is located in Pusan national university and optimize neutron target. To get nice quality of neutrons, it is necessary to study neutron flux and neutron energy spectrum. In order to get neutronic data, the simulation is conducted by using Monte Carlo method with Geant4 code. Regarding target design, which is consist of Beryllium target, metal layer and cooling system, simulation is conducted below many different combinations.

  15. The influence of plasma horizontal position on the neutron rate and flux of neutral atoms in injection heating experiment on the TUMAN-3M tokamak

    Science.gov (United States)

    Kornev, V. A.; Chernyshev, F. V.; Melnik, A. D.; Askinazi, L. G.; Wagner, F.; Vildjunas, M. I.; Zhubr, N. A.; Krikunov, S. V.; Lebedev, S. V.; Razumenko, D. V.; Tukachinsky, A. S.

    2013-11-01

    Horizontal displacement of plasma along the major radius has been found to significantly influence the fluxes of 2.45 MeV DD neutrons and high-energy charge-exchange atoms from neutral beam injection (NBI) heated plasma of the TUMAN-3M tokamak. An inward shift by Δ R = 1 cm causes 1.2-fold increase in the neutron flux and 1.9-fold increase in the charge-exchange atom flux. The observed increase in the neutron flux is attributed to joint action of several factors-in particular, improved high-energy ion capture and confinement and, probably, decreased impurity inflow from the walls, which leads to an increase in the density of target ions. A considerable increase in the flux of charge-exchange neutrals in inward-shifted plasma is due to the increased number of captured high-energy ions and, to some extent, the increased density of the neutral target. As a result of the increase in the content of high-energy ions, the central ion temperature T i (0) increased from 250 to 350 eV. The dependence of the neutron rate on major radius R 0 should be taken into account when designing compact tokamak-based neutron sources.

  16. Neutron anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, G.E. [Univ. of Sheffield (United Kingdom)

    1994-12-31

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone.

  17. Neutron and X-ray Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Carini, Gabriella [SLAC National Accelerator Lab., Menlo Park, CA (United States); Denes, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gruener, Sol [Cornell Univ., Ithaca, NY (United States); Lessner, Elianne [Dept. of Energy (DOE), Washington DC (United States). Office of Science Office of Basic Energy Sciences

    2012-08-01

    The Basic Energy Sciences (BES) X-ray and neutron user facilities attract more than 12,000 researchers each year to perform cutting-edge science at these state-of-the-art sources. While impressive breakthroughs in X-ray and neutron sources give us the powerful illumination needed to peer into the nano- to mesoscale world, a stumbling block continues to be the distinct lag in detector development, which is slowing progress toward data collection and analysis. Urgently needed detector improvements would reveal chemical composition and bonding in 3-D and in real time, allow researchers to watch “movies” of essential life processes as they happen, and make much more efficient use of every X-ray and neutron produced by the source The immense scientific potential that will come from better detectors has triggered worldwide activity in this area. Europe in particular has made impressive strides, outpacing the United States on several fronts. Maintaining a vital U.S. leadership in this key research endeavor will require targeted investments in detector R&D and infrastructure. To clarify the gap between detector development and source advances, and to identify opportunities to maximize the scientific impact of BES user facilities, a workshop on Neutron and X-ray Detectors was held August 1-3, 2012, in Gaithersburg, Maryland. Participants from universities, national laboratories, and commercial organizations from the United States and around the globe participated in plenary sessions, breakout groups, and joint open-discussion summary sessions. Sources have become immensely more powerful and are now brighter (more particles focused onto the sample per second) and more precise (higher spatial, spectral, and temporal resolution). To fully utilize these source advances, detectors must become faster, more efficient, and more discriminating. In supporting the mission of today’s cutting-edge neutron and X-ray sources, the workshop identified six detector research challenges

  18. Measurement of neutron total cross-sections of 209Bi at the Pohang Neutron Facility

    CERN Document Server

    Wang, Tao-Feng; Kim, Guinyun

    2014-01-01

    Measurements of neutron total cross-sections of natural bismuth in the neutron energy region from 0.1 eV to 100 eV have been performed by using the time-of-flight method at the Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled tantalum target with a water moderator, and a 12-m-long time-of-flight path. A 6Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm is employed as a neutron detector, and a piece of high purity natural bismuth metallic plates with a thickness of 3 mm is used for the neutron transmission measurement. The present results were compared with the evaluated data from ENDF/B VII.1 and other previous reported experimental data.

  19. Feasibility of neutron diffraction on solid 3He

    Science.gov (United States)

    Siemensmeyer, K.; Schuberth, E. A.; Adams, E. D.; Takano, Y.; Guckelsberger, K.

    2000-07-01

    We have investigated the feasibility of neutron diffraction from solid 3He. The experiment will be performed at the HMI, first aiming for the properties of the antiferromagnetic ordering in the BCC phase and the ferromagnetic order in the HCP phase. Signal and beam heating considerations are essential to account for the enormous neutron absorption cross section of 3He. The study shows that neutron diffraction and transmission experiments are possible, relying on the experience gained from the neutron diffraction experiments on Cu and Ag at nanokelvin temperatures. A pressure cell has been developed which complies with the conflicting demands arising from the neutron and ultralow temperature aspects of the experiment. This work is a first step in an extensive effort to characterize 3He by neutron diffraction.

  20. Neutron transfer reactions in the fp-shell region

    Energy Technology Data Exchange (ETDEWEB)

    Mahgoub, Mahmoud

    2008-06-26

    Neutron transfer reactions were used to study the stability of the magic number N=28 near {sup 56}Ni. On one hand the one-neutron pickup (d,p) reaction was used for precision spectroscopy of single-particle levels in {sup 55}Fe. On the other hand we investigated the two-neutron transfer mechanism into {sup 56}Ni using the pickup reaction {sup 58}Ni((vector)p,t){sup 56}Ni. In addition the reliability of inverse kinematics reactions at low energy to study exotic nuclei was tested by the neutron transfer reactions t({sup 40}Ar,p){sup 42}Ar and d({sup 54}Fe,p){sup 55}Fe using tritium and deuterium targets, respectively, and by comparing the results with those of the normal kinematics reactions. The experimental data, differential cross-section and analyzing powers, are compared to DWBA and coupled channel calculations utilizing the code CHUCK3. By performing the single-neutron stripping reaction ((vector)d,p) on {sup 54}Fe the 1f{sub 7/2} shell in the ground state configuration was found to be partly broken. The instability of the 1f{sub 7/2} shell and the magic number N=28 was confirmed once by observing a number of levels with J{sup {pi}} = 7/2{sup -} at low excitation energies, which should not be populated if {sup 54}Fe has a closed 1f{sub 7/2} shell, and also by comparing our high precision experimental data with a large scale shell model calculation using the ANTOINE code [5]. Calculations including a partly broken 1f{sub 7/2} shell show better agreement with the experiment. The instability of the 1f{sub 7/2} shell was confirmed also by performing the two-neutron pick-up reaction ((vector)p,t) on {sup 58}Ni to study {sup 56}Ni, where a considerable improvement in the DWBA calculation was observed after considering 1f{sub 7/2} as a broken shell. To prove the reliability of inverse kinematics transfer reactions at low energies ({proportional_to} 2 AMeV), the aforementioned single-neutron transfer reaction (d,p) was repeated using a beam of {sup 54}Fe ions and a

  1. Neutrons production in thick targets of Be and {sup 238}U bombarded by 100 MeV/u deuterons and in a thick target of C bombarded by 95 MeV/u {sup 36}Ar. Attenuation in concrete and dose equivalent rate of the activated uranium; Neutrons produits dans des cibles epaisses de Be et {sup 238}U irradiees par des deutons de 100 MeV/u et dans une cible epaisse de C irradiee par des {sup 36}Ar de 95 MeV/u. Longueurs d'attenuation dans du beton et debit d'equivalent de dose resultant de l'activation de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Pauwels, N.; Proust, J.; Clapier, F.; Gara, P.; Obert, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Mirea, M. [Institute of Physics and Nuclear Engineering, Bucharest (Romania); Belier, G.; Ethvignot, T.; Granier, T. [CEA/DAM-Ile de France, 91 - Bruyeres-Le-Chatel (France). Service de Physique Nucleaire; Liang, C.F. [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse; Bajard, M.; Leroy, R.; Villari, A.C.C. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)

    1999-09-01

    Neutrons production in thick targets of Be and {sup 238}U bombarded by 100 MeV/u deuterons and in a thick target of C bombarded by 95 MeV/u {sup 36}Ar. Attenuation in concrete and dose equivalent rate of the activated uranium. The yields of secondary neutrons produced by the interaction of a beam with thick target were determined with activation detectors. Three projectile-target couples have been studied: deuterons (100 MeV/u)+{sup 238}U, deuterons (100 MeV/u)+{sup 9}Be and {sup 36}Ar (95 MeV/u)+{sup 12}C. At 0 deg.. the yields were also measured after a piece of concrete and the corresponding attenuation length evaluated. The dose rate of the uranium target was monitored during several days after the end of the irradiation. (author)

  2. Imaging with Scattered Neutrons

    OpenAIRE

    Ballhausen, H.; Abele, H.; Gaehler, R.; Trapp, M.; Van Overberghe, A.

    2006-01-01

    We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-re...

  3. Neutron Scattering Differential Cross Sections for 12C

    Science.gov (United States)

    Byrd, Stephen T.; Hicks, S. F.; Nickel, M. T.; Block, S. G.; Peters, E. E.; Ramirez, A. P. D.; Mukhopadhyay, S.; McEllistrem, M. T.; Yates, S. W.; Vanhoy, J. R.

    2016-09-01

    Because of the prevalence of its use in the nuclear energy industry and for our overall understanding of the interactions of neutrons with matter, accurately determining the effects of fast neutrons scattering from 12C is important. Previously measured 12C inelastic neutron scattering differential cross sections found in the National Nuclear Data Center (NNDC) show significant discrepancies (>30%). Seeking to resolve these discrepancies, neutron inelastic and elastic scattering differential cross sections for 12C were measured at the University of Kentucky Acceleratory Laboratory for incident neutron energies of 5.58, 5.83, and 6.04 MeV. Quasi mono-energetic neutrons were scattered off an enriched 12C target (>99.99%) and detected by a C6D6 liquid scintillation detector. Time-of-flight (TOF) techniques were used to determine scattered neutron energies and allowed for elastic/inelastic scattering distinction. Relative detector efficiencies were determined through direct measurements of neutrons produced by the 2H(d,n) and 3H(p,n) source reactions, and absolute normalization factors were found by comparing 1H scattering measurements to accepted NNDC values. This experimental procedure has been successfully used for prior neutron scattering measurements and seems well-suited to our current objective. Significant challenges were encountered, however, with measuring the neutron detector efficiency over the broad incident neutron energy range required for these measurements. Funding for this research was provided by the National Nuclear Security Administration (NNSA).

  4. Characteristics of the WNR: a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; Lisowski, P.W.; Howe, S.D.; King, N.S.P.; Meier, M.M.

    1982-01-01

    The Weapons Neutron Research facility (WNR) is a pulsed spallation neutron source in operation at the Los Alamos National Laboratory. The WNR uses part of the 800-MeV proton beam from the Clinton P. Anderson Meson Physics Facility accelerator. By choosing different target and moderator configurations and varying the proton pulse structure, the WNR can provide a white neutron source spanning the energy range from a few MeV to 800 MeV. The neutron spectrum from a bare target has been measured and is compared with predictions using an Intranuclear Cascade model coupled to a Monte Carlo transport code. Calculations and measurements of the neutronics of WNR target-moderator assemblies are presented.

  5. Flexible neutron shielding composite material of EPDM rubber with boron trioxide: Mechanical, thermal investigations and neutron shielding tests

    Science.gov (United States)

    Özdemir, T.; Güngör, A.; Reyhancan, İ. A.

    2017-02-01

    In this study, EPDM and boron trioxide composite was produced and mechanical, thermal and neutron shielding tests were performed. EPDM rubber (Ethylene Propylene Diene Monomer) having a considerably high hydrogen content is an effective neutron shielding material. On the other hand, the materials containing boron components have effective thermal neutron absorption crossection. The composite of EPDM and boron trioxide would be an effective solution for both respects of flexibility and effectiveness for developing a neutron shielding material. Flexible nature of EPDM would be a great asset for the shielding purpose in case of intervention action to a radiation accident. The theoretical calculations and experimental neutron absorption tests have shown that the results were in parallel and an effective neutron shielding has been achieved with the use of the developed composite material.

  6. International Neutron Radiography Newsletter

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1986-01-01

    At the First World Conference on Neutron Radiography i t was decided to continue the "Neutron Radiography Newsletter", published previously by J.P. Barton, as the "International Neutron Radiography Newsletter" (INRNL), with J.C. Doraanus as editor. The British Journal of Non-Destructive Testing...

  7. Advanced neutron absorber materials

    Science.gov (United States)

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  8. Prototype Neutron Energy Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production [ship effect], [a, n] reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  9. Eikonal reaction theory for two-neutron removal reactions

    CERN Document Server

    Minomo, K; Egashira, K; Ogata, K; Yahiro, M

    2014-01-01

    The eikonal reaction theory (ERT) proposed lately is a method of calculating one-neutron removal reactions at intermediate incident energies in which Coulomb breakup is treated accurately with the continuum discretized coupled-channels method. ERT is extended to two-neutron removal reactions. ERT reproduces measured one- and two-neutron removal cross sections for 6He scattering on 12C and 208Pb targets at 240 MeV/nucleon and also on a 28Si target at 52 MeV/nucleon. For the heavier target in which Coulomb breakup is important, ERT yields much better agreement with the measured cross sections than the Glauber model.

  10. Dual-sided microstructured semiconductor neutron detectors (DSMSNDs)

    Energy Technology Data Exchange (ETDEWEB)

    Fronk, Ryan G., E-mail: rfronk@ksu.edu [Mechanical and Nuclear Engineering Department, Kansas State University, Manhattan, KS 66506, United States (United States); Bellinger, Steven L.; Henson, Luke C. [Radiation Detection Technologies, Inc., Manhattan, KS 66502 (United States); Ochs, Taylor R.; Smith, Colten T.; Kenneth Shultis, J.; McGregor, Douglas S. [Mechanical and Nuclear Engineering Department, Kansas State University, Manhattan, KS 66506, United States (United States)

    2015-12-21

    Microstructured semiconductor neutron detectors (MSNDs) have in recent years received much interest as high-efficiency replacements for thin-film-coated thermal neutron detectors. The basic device structure of the MSND involves micro-sized trenches that are etched into a vertically-oriented pvn-junction diode that are backfilled with a neutron converting material. Neutrons absorbed within the converting material induce fission of the parent nucleus, producing a pair of energetic charged-particle reaction products that can be counted by the diode. The MSND deep-etched microstructures produce good neutron-absorption and reaction-product counting efficiencies, offering a 10× improvement in intrinsic thermal neutron detection efficiency over thin-film-coated devices. Performance of present-day MSNDs are nearing theoretical limits; streaming paths between the conversion-material backfilled trenches, allow a considerable fraction of neutrons to pass undetected through the device. Dual-sided microstructured semiconductor neutron detectors (DSMSNDs) have been developed that utilize a complementary second set of trenches on the back-side of the device to count streaming neutrons. DSMSND devices are theoretically capable of greater than 80% intrinsic thermal neutron detection efficiency for a 1-mm thick device. The first such prototype DSMSNDs, presented here, have achieved 29.48±0.29% nearly 2× better than MSNDs with similar microstructure dimensions.

  11. Dual-sided microstructured semiconductor neutron detectors (DSMSNDs)

    Science.gov (United States)

    Fronk, Ryan G.; Bellinger, Steven L.; Henson, Luke C.; Ochs, Taylor R.; Smith, Colten T.; Kenneth Shultis, J.; McGregor, Douglas S.

    2015-12-01

    Microstructured semiconductor neutron detectors (MSNDs) have in recent years received much interest as high-efficiency replacements for thin-film-coated thermal neutron detectors. The basic device structure of the MSND involves micro-sized trenches that are etched into a vertically-oriented pvn-junction diode that are backfilled with a neutron converting material. Neutrons absorbed within the converting material induce fission of the parent nucleus, producing a pair of energetic charged-particle reaction products that can be counted by the diode. The MSND deep-etched microstructures produce good neutron-absorption and reaction-product counting efficiencies, offering a 10× improvement in intrinsic thermal neutron detection efficiency over thin-film-coated devices. Performance of present-day MSNDs are nearing theoretical limits; streaming paths between the conversion-material backfilled trenches, allow a considerable fraction of neutrons to pass undetected through the device. Dual-sided microstructured semiconductor neutron detectors (DSMSNDs) have been developed that utilize a complementary second set of trenches on the back-side of the device to count streaming neutrons. DSMSND devices are theoretically capable of greater than 80% intrinsic thermal neutron detection efficiency for a 1-mm thick device. The first such prototype DSMSNDs, presented here, have achieved 29.48±0.29% nearly 2× better than MSNDs with similar microstructure dimensions.

  12. Active Target Simulation

    Science.gov (United States)

    Smith, Nathan; Draznik, Peter; Frank, Nathan

    2012-10-01

    We have simulated an existing experimental design to determine the resolution improvement upon energy measurements of neutron unbound nuclei. A number of experiments of this type have been performed at the National Superconducting Cyclotron Laboratory (NSCL), located at Michigan State University. An excited nucleus is typically produced with a radioactive beam interacting with a passive Beryllium target. Many different nuclei are produced in experiment, each of which immediately decays into a charged particle and neutron. The charged particles are detected and the neutrons interact in scintillation detectors such as the Modular Neutron Array (MoNA) and Large Multi-Institutional Scintillation Array (LISA). In our simulation, we have constructed an active target that provides additional information such that the point of nuclear interaction within the target may be determined. This information improves the resolution in decay energy measurements of neutron unbound isotopes. This presentation will cover some aspects of the simulation process, as well as showing some of the results that demonstrate the simulated improvement over a passive target.

  13. "Cavitation in a Mercury Target"

    Energy Technology Data Exchange (ETDEWEB)

    West, C.D.

    2000-09-06

    Recent theoretical work on the formation of bubble nucleation centers by energetic particles leads to some reasonably credible calculations of the maximum negative pressure that might be sustained without bubble formation in the mercury target of the Spallation Neutron Source.

  14. Cavitation in a Mercury Target

    Energy Technology Data Exchange (ETDEWEB)

    West, C.D.

    2000-09-01

    Recent theoretical work on the formation of bubble nucleation centers by energetic particles leads to some reasonably credible calculations of the maximum negative pressure that might be sustained without bubble formation in the mercury target of the Spallation Neutron Source.

  15. Neutron field produced by 25 MeV deuteron on thick beryllium for radiobiological study; energy spectrum.

    Science.gov (United States)

    Takada, Masashi; Mihara, Erika; Sasaki, Michiya; Nakamura, Takashi; Honma, Toshihiko; Kono, Koji; Fujitaka, Kazunobu

    2004-01-01

    Biological data is necessary for estimation of protection from neutrons, but there is a lack of data on biological effects of neutrons for radiation protection. Radiological study on fast neutrons has been done at the National Institute of Radiological Sciences. An intense neutron source has been produced by 25 MeV deuterons on a thick beryllium target. The neutron energy spectrum, which is essential for neutron energy deposition calculation, was measured from thermal to maximum energy range by using an organic liquid scintillator and multi-sphere moderated 3He proportional counters. The spectrum of the gamma rays accompanying the neutron beam was measured simultaneously with the neutron spectrum using the organic liquid scintillator. The transmission by the shield of the spurious neutrons originating from the target was measured to be less than 1% by using the organic liquid scintillator placed behind the collimator. The measured neutron energy spectrum is useful in dose calculations for radiobiology studies.

  16. Current status of Pohang Neutron Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G.N.; Lee, Y.S.; Cho, M.H. [Pohang Accelerator Laboratory, POSTECH, Pohang (KR)] [and others

    2000-03-01

    We present the current status of Pohang Neutron Facility, which is the pulsed neutron facility, based on the 70-MeV electron linear accelerator completed on Dec.1997. We have prepared the 15-m time-of-flight path, a Ta-target system, and the Data Acquisition System. Meanwhile we have measured the total cross-sections of Dy and Hf samples at the Research Reactor Institute, Kyoto University and the neutron capture cross-sections of {sup 164}Dy isotope at Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology both in Japan. We also were participated the experiment at the 122-m flight path of the IBR-30 pulsed neutron source of Joint Institute of Nuclear Research in Dubna, Russia. (author)

  17. The requirements and development of neutron beams for neutron capture therapy of brain cancer.

    Science.gov (United States)

    Moss, R L; Aizawa, O; Beynon, D; Brugger, R; Constantine, G; Harling, O; Liu, H B; Watkins, P

    1997-05-01

    One of the two overriding conditions for successful BNCT is that there must be a sufficient number of thermal neutrons delivered to each of the boronated cells in the tumour bed (target volume). Despite the poor experience with BNCT in the USA some 40 years ago, the continued apparent success of BNCT in Japan since 1968, lead indirectly to the re-start of clinical trials on BNCT in 1994 at both Brookhaven and MIT. Similar trials will start soon at Petten in Europe. At other centres worldwide, many neutron beam designs are being proposed with either thermal or epithermal neutrons, emanating predominantly from nuclear research reactors. It is apparent that whilst the success of BNCT depends on a suitable neutron beam, there is a diversity in available designs, as well as each proposed type of neutron source, with consequently different characteristics of the emergent neutron beam. The paper presents the historical development of neutron beams used for BNCT, addresses the requirements on the types of beams, describes some of the existing designs and other proposals elsewhere and lastly, considers the broader requirements in designing NCT facilities. The focus of the paper is on treatment of brain cancer, neutron beam requirements for other types of cancer may vary.

  18. 2010 Neutron Review: ORNL Neutron Sciences Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Bardoel, Agatha A [ORNL; Counce, Deborah M [ORNL; Ekkebus, Allen E [ORNL; Horak, Charlie M [ORNL; Nagler, Stephen E [ORNL; Kszos, Lynn A [ORNL

    2011-06-01

    pnictides and chalcogenides), a class of materials discovered in 2008. This research is yielding new insights into the relationship between magnetism and superconductivity and has established several key features of this family of high-temperature superconducting (HTS ) materials: the maximum magnetic field at which they can function, the nature of the electrons involved in the superconductivity, the dependence of the properties upon chemical substitution, and the character of the magnetic fluctuations in the material. The results suggest that despite important differences between these materials and the HTS copper oxides, a universal mechanism may be responsible for the unconventional superconductivity. (4) Coal Sequestration Research: A New Home for Greenhouse Gases - One possibility for slowing down the increasing levels of carbon dioxide (CO{sub 2}) in the atmosphere is to capture the gas in natural underground features such as coal seams. Critical to the feasibility of this technology is determining how much CO{sub 2} can be stored, no method for which has been found - until now. (5) Accelerator Reliability Passes 92% - In December 2010, SNS set a new record for itself when the accelerator ran at 1 MW with 100% reliability. Target Performance Exceeds All Expectations - The mercury target used at SNS is the first of its kind. During the design and planning for SNS, many people were skeptical that the target would work. In 2010, it was confirmed that the target was working not only well but much better than anyone would have imagined. (6) Changing the World of Data Acquisition - Researchers at SNS are starting to benefit from event-based data analysis. Event data mode captures and stores an individual data set for every single neutron that strikes a detector - precisely when and where the neutron is detected. This technique provides numerous advantages over traditional methods. Event data mode allows researchers to process their data at the highest resolution possible

  19. Characterization of neutron yield and x-ray spectra of a High Flux Neutron Generator (HFNG)

    Science.gov (United States)

    Nnamani, Nnaemeka; HFNG Collaboration

    2015-04-01

    The High Flux Neutron Generator (HFNG) is a DD plasma-based source, with a self-loading target intended for fundamental science and engineering applications, including 40 Ar/39 Ar geochronology, neutron cross section measurements, and radiation hardness testing of electronics. Our first estimate of the neutron yield, based on the population of the 4.486 hour 115 In isomer gave a neutron yield of the order 108 n/sec; optimization is ongoing to achieve the design target of 1011 n/sec. Preliminary x-ray spectra showed prominent energy peaks which are likely due to atomic line-emission from back-streaming electrons accelerated up to 100 keV impinging on various components of the HFNG chamber. Our x-ray and neutron diagnostics will aid us as we continue to evolve the design to suppress back-streaming electrons, necessary to achieve higher plasma beam currents, and thus higher neutron flux. This talk will focus on the characterization of the neutron yield and x-ray spectra during our tests. A collimation system is being installed near one of the chamber ports for improved observation of the x-ray spectra. This work is supported by NSF Grant No. EAR-0960138, U.S. DOE LBNL Contract No. DE-AC02-05CH11231, U.S. DOE LLNL Contract No. DE-AC52-07NA27344, and the UC Office of the President Award 12-LR-238745.

  20. ITEP ElectroNuclear neutron and proton facility

    Energy Technology Data Exchange (ETDEWEB)

    Shvedoy, O.V.; Igumnov, M.I.; Katz, M.M.; Kolomietz, A.A.; Kozodaev, A.M.; Lazarev, N.V.; Vasilyev, V.V.; Volkov, E.B.; Shymchukk, G.V. [State Science Centre of Russian Federation, Institute of Theoretical and Experimental Physics, (Russian Federation)

    1997-10-01

    Construction and current stage of the ITEP Subcritical Facility on the base will be described. The facility uses 36 MeV protons, Be neutron producing target and heavy water reflector. Neutron and proton beam parameters are listed. Special attention is devoted to isotope production and isotope application for e{sup -}--e{sup +} tomography 5 refs., 5 tabs., 1fig.

  1. Neutron and Alpha Structure in Neutron Deficient Nuclei in Astrophysics

    Institute of Scientific and Technical Information of China (English)

    S. Kubono; T. Hashimoto; Y. Wakabayashi; N. Iwasa; S. Kato; T. Komatsubara; D. N. Binh; L. H. Khiem; N. N. Duy; T. Kawabata; C. Spitaleri; 何建军; G. G. Rapisarda; M. La Cognata; L. Lamia; R. G. Pizzone; S. Romano; A. Coc; N. de Sereville; F. Hammache; G. Kiss; S. Bishop; H. Yamaguchi; D. M. Kahl; S. Hayakawa; T. Teranishi; S. Cheribini; M. Gulino; Y. K. Kwon

    2016-01-01

    The paper includes discussions on the important role of neutron and alpha configurations in proton-rich nuclei in nuclear astrophysics in terms of nucleosynthesis under extremely high-temperature hydrogenburning conditions. The νp-process, which is supposed to take place at the very early epoch of type II supernovae, has considerable neutrons and alphas together with protons. The alpha-induced reactions on proton-rich unstable nuclei in the light mass regions is expected to play a crucial role, but very few of them were investigated well yet because of the experimental difficulties. Specifically, I report our recent experimental effort for the breakout process from the pp-chain region, 7Be(α,γ)11C(α,p)14N under the νp-process. The neutron-induced reactions on proton-rich nuclei, which is even more a challenging subject, were investigated previously for very few nuclei. One possible experimental method is the Trojan Horse Method (THM). We successfully have applied THM to the 18F(n,α)14N reaction study with an unstable beam of 18F.

  2. Design of a transportable high efficiency fast neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Roecker, C., E-mail: calebroecker@berkeley.edu [Department of Nuclear Engineering, University of California at Berkeley, CA 94720 (United States); Bernstein, A.; Bowden, N.S. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Cabrera-Palmer, B. [Radiation and Nuclear Detection Systems, Sandia National Laboratories, Livermore, CA 94550 (United States); Dazeley, S. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Gerling, M.; Marleau, P.; Sweany, M.D. [Radiation and Nuclear Detection Systems, Sandia National Laboratories, Livermore, CA 94550 (United States); Vetter, K. [Department of Nuclear Engineering, University of California at Berkeley, CA 94720 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-08-01

    A transportable fast neutron detection system has been designed and constructed for measuring neutron energy spectra and flux ranging from tens to hundreds of MeV. The transportability of the spectrometer reduces the detector-related systematic bias between different neutron spectra and flux measurements, which allows for the comparison of measurements above or below ground. The spectrometer will measure neutron fluxes that are of prohibitively low intensity compared to the site-specific background rates targeted by other transportable fast neutron detection systems. To measure low intensity high-energy neutron fluxes, a conventional capture-gating technique is used for measuring neutron energies above 20 MeV and a novel multiplicity technique is used for measuring neutron energies above 100 MeV. The spectrometer is composed of two Gd containing plastic scintillator detectors arranged around a lead spallation target. To calibrate and characterize the position dependent response of the spectrometer, a Monte Carlo model was developed and used in conjunction with experimental data from gamma ray sources. Multiplicity event identification algorithms were developed and used with a Cf-252 neutron multiplicity source to validate the Monte Carlo model Gd concentration and secondary neutron capture efficiency. The validated Monte Carlo model was used to predict an effective area for the multiplicity and capture gating analyses. For incident neutron energies between 100 MeV and 1000 MeV with an isotropic angular distribution, the multiplicity analysis predicted an effective area of 500 cm{sup 2} rising to 5000 cm{sup 2}. For neutron energies above 20 MeV, the capture-gating analysis predicted an effective area between 1800 cm{sup 2} and 2500 cm{sup 2}. The multiplicity mode was found to be sensitive to the incident neutron angular distribution.

  3. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  4. Grazing Incidence Neutron Optics

    Science.gov (United States)

    Gubarev, Mikhail V. (Inventor); Ramsey, Brian D. (Inventor); Engelhaupt, Darell E. (Inventor)

    2013-01-01

    Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20.ANG.. The replication techniques can be also be used to fabricate neutron beam controlling guides.

  5. Neutron scatter camera

    Science.gov (United States)

    Mascarenhas, Nicholas; Marleau, Peter; Brennan, James S.; Krenz, Kevin D.

    2010-06-22

    An instrument that will directly image the fast fission neutrons from a special nuclear material source has been described. This instrument can improve the signal to background compared to non imaging neutron detection techniques by a factor given by ratio of the angular resolution window to 4.pi.. In addition to being a neutron imager, this instrument will also be an excellent neutron spectrometer, and will be able to differentiate between different types of neutron sources (e.g. fission, alpha-n, cosmic ray, and D-D or D-T fusion). Moreover, the instrument is able to pinpoint the source location.

  6. On the limit of neutron fluxes in the fission-based pulsed neutron sources

    Science.gov (United States)

    Aksenov, V. L.; Ananiev, V. D.; Komyshev, G. G.; Rogov, A. D.; Shabalin, E. P.

    2017-09-01

    The upper limit of the density of the thermal neutron flux from pulsed sources based on the fission reaction is established. Three types of sources for research on ejected beams are considered: a multiplying target of the proton accelerator (a booster), a booster with the reactivity modulation (a superbooster), and a pulsing reactor. Comparison with other high-flux sources is carried out. The investigation has been performed at the Frank Laboratory of Neutron Physics of JINR.

  7. Single-Neutron Structure of Neutron-Rich Nuclei near N=50 and N=82

    Energy Technology Data Exchange (ETDEWEB)

    Cizewski, J. A. [Rutgers University; Jones, K. L. [University of Tennessee, Knoxville (UTK); Kozub, R. L. [Tennessee Technological University; Pain, S. D. [Rutgers University; Bardayan, Daniel W [ORNL; Blackmon, Jeff C [ORNL; Adekola, Aderemi S [ORNL; Chae, K. Y. [University of Tennessee, Knoxville (UTK); Chipps, K. [Colorado School of Mines, Golden; Erikson, Luke [Colorado School of Mines, Golden; Gaddis, A. L. [Furman University; Harlin, Christopher W [ORNL; Hatarik, Robert [Rutgers University; Howard, Joshua A [ORNL; Kaplan, Ron [ORNL; Krolas, W. [University of Warsaw; Liang, J Felix [ORNL; Livesay, Jake [ORNL; Ma, Zhanwen [ORNL; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Moazen, Brian [University of Tennessee, Knoxville (UTK); Nesaraja, Caroline D [ORNL; O' Malley, Patrick [Rutgers University; Patterson, N. P. [University of Surrey, UK; Paulauskas, Stanley [University of Tennessee, Knoxville (UTK); Shapira, Dan [ORNL; Shriner, Jr., John F [ORNL; Sissom, D. J. [Tennessee Technological University; Smith, Michael Scott [ORNL; Swan, T. P. [University of Surrey, UK; Thomas, J. S. [Rutgers University; Wilson, Gemma L [ORNL

    2009-01-01

    The 82Ge, 84Se, 132Sn, 130Sn, and 134Te (d,p) reactions have been measured with {approx}4-5-MeV-A rare isotope beams and CD2 targets at the HRIBF at ORNL. Energies and spectroscopic strengths have been measured for excitations in 83Ge and 85Se. Direct neutron capture calculations on 82Ge are presented. Preliminary results for single-neutron excitations in 131Sn, 133Sn, and 135Te are reported.

  8. In target yields for EURISOL RIB production

    CERN Document Server

    Ene, D; David, J.-C; Chabod, S

    The goal of this paper is the estimation of the in-target neutron-induced fission fragment productions using the most recent optimized design of the EURISOL converter-fission target assembly.Submitted to EPJA.

  9. Spin distribution in neutron induced preequilibrium reactions

    Energy Technology Data Exchange (ETDEWEB)

    Dashdorj, D; Kawano, T; Chadwick, M; Devlin, M; Fotiades, N; Nelson, R O; Mitchell, G E; Garrett, P E; Agvaanluvsan, U; Becker, J A; Bernstein, L A; Macri, R; Younes, W

    2005-10-04

    The preequilibrium reaction mechanism makes an important contribution to neutron-induced reactions above E{sub n} {approx} 10 MeV. The preequilibrium process has been studied exclusively via the characteristic high energy neutrons produced at bombarding energies greater than 10 MeV. They are expanding the study of the preequilibrium reaction mechanism through {gamma}-ray spectroscopy. Cross-section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy (E{sub n} = 1 to 250 MeV) on a {sup 48}Ti sample. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the Los Alamos Neutron Science Center facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The {gamma}-ray excitation functions were converted to partial {gamma}-ray cross sections taking into account the dead-time correction, target thickness, detector efficiency and neutron flux (monitored with an in-line fission chamber). Residual state population was predicted using the GNASH reaction code, enhanced for preequilibrium. The preequilibrium reaction spin distribution was calculated using the quantum mechanical theory of Feshback, Kerman, and Koonin (FKK). The multistep direct part of the FKK theory was calculated for a one-step process. The FKK preequilibrium spin distribution was incorporated into the GNASH calculations and the {gamma}-ray production cross sections were calculated and compared with experimental data. The difference in the partial {gamma}-ray cross sections using spin distributions with and without preequilibrium effects is significant.

  10. Neutron multiplicity measurements with 3He alternative: Straw neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, Sanjoy [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Wolff, Ronald [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Detwiler, Ryan [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Maurer, Richard [Arnold Avenue Andrews AFB, Joint Base Andrews, MD (United States); Mitchell, Stephen [National Security Technologies, LLC, Las Vegas, NV (United States); Guss, Paul [Remote Sensing Lab. - Nellis, Las Vegas, NV (United States); Lacy, Jeffrey L. [Proportional Technologies, Inc., Houston, TX (United States); Sun, Liang [Proportional Technologies, Inc., Houston, TX (United States); Athanasiades, Athanasios [Proportional Technologies, Inc., Houston, TX (United States)

    2015-01-27

    Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as ‘‘ship effect ’’) and to the complicated nature of the neutron scattering in that environment. A prototype neutron detector was built using 10B as the converter in a special form factor called ‘‘straws’’ that would address the above problems by looking into the details of multiplicity distributions of neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and

  11. Lead - nutritional considerations

    Science.gov (United States)

    Lead poisoning - nutritional considerations; Toxic metal - nutritional considerations ... Markowitz M. Lead poisoning. In: Kliegman RM, Behrman RE, Jenson HB, ... Emergency Medicine: Concepts and Clinical Practice . 8th ed. ...

  12. Advances in neutron tomography

    Indian Academy of Sciences (India)

    W Treimer

    2008-11-01

    In the last decade neutron radiography (NR) and tomography (NCT) have experienced a number of improvements, due to the well-known properties of neutrons interacting with matter, i.e. the low attenuation by many materials, the strong attenuation by hydrogenous constituent in samples, the wavelength-dependent attenuation in the neighbourhood of Bragg edges and due to better 2D neutron detectors. So NR and NCT were improved by sophisticated techniques that are based on the attenuation of neutrons or on phase changes of the associated neutron waves if they pass through structured materials. Up to now the interaction of the neutron spin with magnetic fields in samples has not been applied to imaging techniques despite the fact that it was proposed many years ago. About ten years ago neutron depolarization as imaging signal for neutron radiography or tomography was demonstrated and in principle it works. Now one can present much improved test experiments using polarized neutrons for radiographic imaging. For this purpose the CONRAD instrument of the HMI was equipped with polarizing and analysing benders very similar to conventional scattering experiments using polarized neutrons. Magnetic fields in different coils and in samples (superconductors) at low temperatures could be visualized. In this lecture a summary about standard signals (attenuation) and the more `sophisticated' imaging signals as refraction, small angle scattering and polarized neutrons will be given.

  13. Monte Carlo Simulation for Moderator of Compact D-T Neutron Generator

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In order to study the neutron moderation of D-T neutron generator, moderators with diffident materials and structures are predicted by Monte Carlo simulations. Neutron generator is simplified as the diameter 20 cm, length 25 cm cylinder. The target is very

  14. Tomsk Polytechnic University cyclotron as a source for neutron based cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    Lisin, V. A. [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation); Tomsk Polytechnic University, 30 Lenina av., Tomsk 634050 (Russian Federation); Bogdanov, A. V.; Golovkov, V. M.; Sukhikh, L. G.; Verigin, D. A., E-mail: verigin@tpu.ru [Tomsk Polytechnic University, 30 Lenina av., Tomsk 634050 (Russian Federation); Musabaeva, L. I. [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation)

    2014-02-15

    In this paper we present our cyclotron based neutron source with average energy 6.3 MeV generated during the 13.6 MeV deuterons interactions with beryllium target, neutron field dosimetry, and dosimetry of attendant gamma fields. We also present application of our neutron source for cancer treatment.

  15. Neutronic Reactor Shield

    Science.gov (United States)

    Fermi, Enrico; Zinn, Walter H.

    The argument of the present Patent is a radiation shield suitable for protection of personnel from both gamma rays and neutrons. Such a shield from dangerous radiations is achieved to the best by the combined action of a neutron slowing material (a moderator) and a neutron absorbing material. Hydrogen is particularly effective for this shield since it is a good absorber of slow neutrons and a good moderator of fast neutrons. The neutrons slowed down by hydrogen may, then, be absorbed by other materials such as boron, cadmium, gadolinium, samarium or steel. Steel is particularly convenient for the purpose, given its effectiveness in absorbing also the gamma rays from the reactor (both primary gamma rays and secondary ones produced by the moderation of neutrons). In particular, in the present Patent a shield is described, made of alternate layers of steel and Masonite (an hydrolized ligno-cellulose material). The object of the present Patent is not discussed in any other published paper.

  16. Spectroscopy of Neutrons Produced by (p,n) Reactions on Lithium

    Science.gov (United States)

    Wielopolski, Lucian; Powell, J.; Ludewig, H.; Raparia, D.; Alessi, J.; Han, Guoping

    1997-05-01

    Alternative to nuclear reactors, epithermal neutron source are being developed for Boron Neutron Capture Therapy (BNCT). Ideally, BNCT requires mono-energetic neutrons from about 1eV to 20keV depending on the tumor depth in brain. Accelerator based filtered neutron beams for BNCT produce continuous neutron spectra that need to be optimised. Neutron spectra resulting from bombarding Li target with protons, with various energies, were measured using proton recoil proportional counters. These spectra were analysed using the PSNS and HEPRO codes. The results from both analysis and Monte Carlo simulations are presented and the issues involved with either of the codes are discussed.

  17. Spectrum shaping of accelerator-based neutron beams for BNCT

    CERN Document Server

    Montagnini, B; Esposito, J; Giusti, V; Mattioda, F; Varone, R

    2002-01-01

    We describe Monte Carlo simulations of three facilities for the production of epithermal neutrons for Boron Neutron Capture Therapy (BNCT) and examine general aspects and problems of designing the spectrum-shaping assemblies to be used with these neutron sources. The first facility is based on an accelerator-driven low-power subcritical reactor, operating as a neutron amplifier. The other two facilities have no amplifier and rely entirely on their primary sources, a D-T fusion reaction device and a conventional 2.5 MeV proton accelerator with a Li target, respectively.

  18. LANSCE '90: The Manuel Lujan Jr. Neutron Scattering Center

    Energy Technology Data Exchange (ETDEWEB)

    Pynn, R.

    1990-01-01

    This paper describes progress that has been made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) during the past two years. Presently, LANSCE provides a higher peak neutron flux than any other pulsed spallation neutron source. There are seven spectrometers for neutron scattering experiments that are operated for a national user program sponsored by the US Department of Energy. Two more spectrometers are under construction. Plans have been made to raise the number of beam holes available for instrumentation and to improve the efficiency of the target/moderator system. 9 refs., 4 figs.

  19. Characterization of Neutron Backgrounds for Direct Dark Matter Searches

    Science.gov (United States)

    Sweany, Melinda Dominique

    Direct dark matter experiments generally cannot distinguish between nuclear recoils caused by Weakly Interacting Massive Particles (WIMPs) and those caused by neutron backgrounds. It is therefore crucial that all sources of neutron background are well understood and accounted for when claiming a discovery or reporting limits on the WIMP-nucleon cross section. One source of neutrons that is not well understood results from cosmogenic muon interactions in the material surrounding a detector. The Neutron Multiplicity Meter in the Soudan cavern is a gadolinium-doped water Cherenkov detector capable of detecting high multiplicity neutron showers resulting from fast neutrons incident on a lead target. This measurement is the first such measurement obtained without a liquid scintillator detector medium; muon and neutron spallation is media-dependent, and because neutron shield technology for dark matter detectors is moving towards water, this is an important measurement. The integrated fast neutron flux in the Soudan cavern is reported as a linear function of the power, alpha, of the neutron angular distribution with the zenith angle: F = 4.8x10-9 +/- 3.5x10-10 + (5.4x10-10 +/- 1.5x10-10)alpha. Technological studies of neutron detection with gadolinium-doped water are also reported here. The neutron detection efficiency of a cylindrical 3.5 kL detector is measured at 70% for neutrons in the center of the detector. In addition, other improvements to water Cherenkov technology are explored, namely the addition of water-soluble wavelength-shifting chemicals. The wavelength-shifting chemical 4-Methylumbelliferone has been shown here to increase the measured light output of Cherenkov radiation resulting from neutron capture showers by a factor of 1.7.

  20. Energy Density Functional for Nuclei and Neutron Stars

    Energy Technology Data Exchange (ETDEWEB)

    Erler, J. [UTK/ORNL/German Cancer Research Center-Heidelberg; Horowitz, C. J. [UTK/ORNL/Indiana University; Nazarewicz, Witold [UTK/ORNL/University of Warsaw; Rafalski, M. [UTK/ORNL; Reinhard, P.-G. [Universitat Erlangen, Germany

    2013-01-01

    Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [ Annu. Rev. Nucl. Part. Sci. 62 485 (2012)]. Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars. Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one. Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of 208Pb and the neutron star radius. Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but it also reproduces expected neutron star data

  1. Epithermal neutron formation for boron neutron capture therapy by adiabatic resonance crossing concept

    Science.gov (United States)

    Khorshidi, A.; Ghafoori-Fard, H.; Sadeghi, M.

    2014-05-01

    Low-energy protons from the cyclotron in the range of 15-30 MeV and low current have been simulated on beryllium (Be) target with a lead moderator around the target. This research was accomplished to design an epithermal neutron beam for Boron Neutron Capture Therapy (BNCT) using the moderated neutron on the average produced from 9Be target via (p, xn) reaction in Adiabatic Resonance Crossing (ARC) concept. Generation of neutron to proton ratio, energy distribution, flux and dose components in head phantom have been simulated by MCNP5 code. The reflector and collimator were designed in prevention and collimation of derivation neutrons from proton bombarding. The scalp-skull-brain phantom consisting of bone and brain equivalent material has been simulated in order to evaluate the dosimetric effect on the brain. Results of this analysis demonstrated while the proton energy decreased, the dose factor altered according to filters thickness. The maximum epithermal flux revealed using fluental, Fe and bismuth (Bi) filters with thicknesses of 9.4, 3 and 2 cm, respectively and also the epithermal to thermal neutron flux ratio was 103.85. The potential of the ARC method to replace or complement the current reactor-based supply sources of BNCT purposes.

  2. High precision thermal neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Radeka, V.; Schaknowski, N.A.; Smith, G.C.; Yu, B. [Brookhaven National Laboratory, Upton, NY (United States)

    1994-12-31

    Two-dimensional position sensitive detectors are indispensable in neutron diffraction experiments for determination of molecular and crystal structures in biology, solid-state physics and polymer chemistry. Some performance characteristics of these detectors are elementary and obvious, such as the position resolution, number of resolution elements, neutron detection efficiency, counting rate and sensitivity to gamma-ray background. High performance detectors are distinguished by more subtle characteristics such as the stability of the response (efficiency) versus position, stability of the recorded neutron positions, dynamic range, blooming or halo effects. While relatively few of them are needed around the world, these high performance devices are sophisticated and fairly complex, their development requires very specialized efforts. In this context, we describe here a program of detector development, based on {sup 3}He filled proportional chambers, which has been underway for some years at the Brookhaven National Laboratory. Fundamental approaches and practical considerations are outlined that have resulted in a series of high performance detectors with the best known position resolution, position stability, uniformity of response and reliability over time, for devices of this type.

  3. Ground-state properties of neutron-rich Mg isotopes

    CERN Document Server

    Watanabe, Shin; Shimada, Mitsuhiro; Tagami, Shingo; Kimura, Masaaki; Takechi, Maya; Fukuda, Mitsunori; Nishimura, Daiki; Suzuki, Takeshi; Matsumoto, Takuma; Shimizu, Yoshifumi R; Yahiro, Masanobu

    2014-01-01

    We analyze recently-measured total reaction cross sections for 24-38Mg isotopes incident on 12C targets at 240 MeV/nucleon by using the folding model and antisymmetrized molecular dynamics(AMD). The folding model well reproduces the measured reaction cross sections, when the projectile densities are evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation. Matter radii of 24-38Mg are then deduced from the measured reaction cross sections by ?ne-tuning the parameters of the def-WS model. The deduced matter radii are largely enhanced by nuclear deformation. Fully-microscopic AMD calculations with no free parameter well reproduce the deduced matter radii for 24-36Mg, but still considerably underestimate them for 37,38Mg. The large matter radii suggest that 37,38Mg are candidates for deformed halo nucleus. AMD also reproduces other existing measured ground-state properties (spin-parity, total binding energy, and one-neutron separation energy) of Mg isotopes. Neutron-number (N) dependence of defor...

  4. The Frankfurt neutron source FRANZ

    Science.gov (United States)

    Alzubaidi, Suha; Bartz, Ulrich; Basten, Markus; Bechtold, Alexander; Chau, Long Phi; Claessens, Christine; Dinter, Hannes; Droba, Martin; Fix, Christopher; Hähnel, Hendrik; Heilmann, Manuel; Hinrichs, Ole; Huneck, Simon; Klump, Batu; Lotz, Marcel; Mäder, Dominik; Meusel, Oliver; Noll, Daniel; Nowottnick, Tobias; Obermayer, Marcus; Payir, Onur; Petry, Nils; Podlech, Holger; Ratzinger, Ulrich; Schempp, Alwin; Schmidt, Stefan; Schneider, Philipp; Seibel, Anja; Schwarz, Malte; Schweizer, Waldemar; Volk, Klaus; Wagner, Christopher; Wiesner, Christoph

    2016-05-01

    A 2MeV proton beam will produce a quasi-Maxwellian neutron spectrum of around 30 keV by the 7Li(p, n)7Be reaction. The experiments are mainly focused on the measurement of differential neutron capture cross sections relevant for the astrophysical s-process in nuclear synthesis. Moreover, proton capture cross sections for the astrophysical p-process can be measured directly with the proton beam. For an efficient time of flight measurement of the neutron energies along the 0.7 m long drift from the Li-target to the sample, 1ns short, intense proton pulses are needed at the target. Additionally, to reach 107 n/cm2/s at the sample, a pulse repetition rate of 250 kHz is intended. After completion and successful running in, FRANZ will become a user facility with internal and external users. The 120 kV injector terminal and the 200mA proton source as well as the low-energy beam transport section and the FRANZ cave have been realized successfully. The 1.9 MV RF accelerator consists of a combined 4-Rod-RFQ/IH-DTL-resonator and is in the RF tuning and power testing phase. The 2 MeV transport and rebuncher section is ready for installation. In a first step FRANZ will offer experimental areas for neutron activation experiments and for proton beam experiments, as mentioned above. From the accelerator physics point of view, FRANZ will be an excellent facility for high current beam investigations and for beam wall interaction studies.

  5. Biological effectiveness of neutron irradiation on animals and man

    Energy Technology Data Exchange (ETDEWEB)

    Straume, T.

    1982-11-01

    Neutron experiments on a highly radiosensitive in vivo system - oocytes in mice - provide new insight into the nature of the radiosensitive targets of these important cells. With the radiobiological literature as background, neutron data from animals and humans are integrated, and the controversial question of radiation protection standards for neutrons is addressed. Oocyte killing in juvenile mice by 0.43-MeV, /sup 252/Cf-fission, and 15 MeV neutrons, compared with that by /sup 60/Co gamma rays, yields unusually low neutron RBEs (relative biological effectiveness). At 0.1 rad of 0.43-MeV neutrons the RBE is only 1.8, contrasting greatly with values of 100 or more reported at low-doses for other endpoints. In mice just prior to birth, however, when oocytes are less radiosensitive, the neutron RBE is much higher, similar to values for most other mammalian endpoints. This dramatic change in neutron RBE with mouse age (occurring within 2 to 3 days) can be explained as the result of a shift from a less radiosensitive target (presumably nuclear DNA) to a much more radiosensitive one (probably the oocyte plasma membrane). Using various approaches, a value for the neutron Quality Factor (Q, a radiation protection standard) is estimated as 17 (+-100%), much lower than 100 which has been suggested. With the large uncertainty, 17 is not markedly different from the value of 10 presently in general use.

  6. Development of cold neutron depth profiling system at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Park, B.G. [Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-355 (Korea, Republic of); Sun, G.M., E-mail: gmsun@kaeri.re.kr [Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon 305-355 (Korea, Republic of); Choi, H.D. [Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2014-07-01

    A neutron depth profiling (NDP) system has been designed and developed at HANARO, a 30 MW research reactor at the Korea Atomic Energy Research Institute (KAERI). The KAERI-NDP system utilizes cold neutrons that are transported along the CG1 neutron guide from the cold neutron source and it consists of a neutron beam collimator, a target chamber, a beam stopper, and charged particle detectors along with NIM-standard modules for charged particle pulse-height analysis. A 60 cm in diameter stainless steel target chamber was designed to control the positions of the sample and detector. The energy distribution of the cold neutron beam at the end of the neutron guide was calculated by using the Monte Carlo simulation code McStas, and a neutron flux of 1.8×10{sup 8} n/cm{sup 2} s was determined by using the gold foil activation method at the sample position. The performance of the charged particle detection of the KAERI-NDP system was tested by using Standard Reference Materials. The energy loss spectra of alpha particles and Li ions emitted from {sup 10}B, which was irradiated by cold neutrons, were measured. The measured peak concentration and the areal density of {sup 10}B in the Standard Reference Material are consistent with the reference values within 1% and 3.4%, respectively.

  7. Development of cold neutron depth profiling system at HANARO

    Science.gov (United States)

    Park, B. G.; Sun, G. M.; Choi, H. D.

    2014-07-01

    A neutron depth profiling (NDP) system has been designed and developed at HANARO, a 30 MW research reactor at the Korea Atomic Energy Research Institute (KAERI). The KAERI-NDP system utilizes cold neutrons that are transported along the CG1 neutron guide from the cold neutron source and it consists of a neutron beam collimator, a target chamber, a beam stopper, and charged particle detectors along with NIM-standard modules for charged particle pulse-height analysis. A 60 cm in diameter stainless steel target chamber was designed to control the positions of the sample and detector. The energy distribution of the cold neutron beam at the end of the neutron guide was calculated by using the Monte Carlo simulation code McStas, and a neutron flux of 1.8×108 n/cm2 s was determined by using the gold foil activation method at the sample position. The performance of the charged particle detection of the KAERI-NDP system was tested by using Standard Reference Materials. The energy loss spectra of alpha particles and Li ions emitted from 10B, which was irradiated by cold neutrons, were measured. The measured peak concentration and the areal density of 10B in the Standard Reference Material are consistent with the reference values within 1% and 3.4%, respectively.

  8. Determination of neutron spectra using the programs GNSR and SPECTRIX

    CERN Document Server

    Weyrauch, M; Matzke, M

    2002-01-01

    We describe the capabilities and the application of two computer programs, which have been developed in order to facilitate common tasks in neutron spectrometry: GNSR (calculation of response matrices) and SPECTRIX (unfolding). Gas-filled Neutron Spectrometer Response calculates response functions and response matrices of various gas-filled neutron detectors. It can be configured to accommodate the appropriate gas-fillings and supports a number of different neutron beam configurations with a possibility to input calculated or measured neutron beam spectra. The program includes graphical capabilities as well as a context-sensitive help system. SPECTRIX implements several unfolding algorithms as well as support algorithms for unfolding and includes graphics capabilities and context-sensitive help. We apply both programs to a specific example: calculation of the response matrix of a sup 3 He detector and unfolding of the neutron spectrum of a thick accelerator target using the calculated response matrix.

  9. Study on neutron radiation field of carbon ions therapy

    CERN Document Server

    Xu, Jun-Kui; Li, Wu-Yuan; Yan, Wei-Wei; Chen, Xi-Meng; Mao, Wang; Pang, Cheng-Guo

    2015-01-01

    Carbon ions offer significant advantages for deep-seated local tumors therapy due to their physical and biological properties. Secondary particles, especially neutrons caused by heavy ion reactions should be carefully considered in treatment process and radiation protection. For radiation protection purposes, the FLUKA Code was used in order to evaluate the radiation field at deep tumor therapy room of HIRFL in this paper. The neutron energy spectra, neutron dose and energy deposition of carbon ion and neutron in tissue-like media was studied for bombardment of solid water target by 430MeV/u C ions. It is found that the calculated neutron dose have a good agreement with the experimental date, and the secondary neutron dose may not exceed one in a thousand of the carbon ions dose at Bragg peak area in tissue-like media.

  10. The second workshop of neutron science research program

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Hideshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tone, Tatsuzo [eds.

    1997-11-01

    The Japan Atomic Energy Research Institute(JAERI) has been proposing the Neutron Science Research Program to explore a broad range of basic research and the nuclear technology including actinide transmutation with use of powerful spallation neutron sources. For this purpose, the JAERI is conducting the research and development of an intense proton linac, the development of targets, as well as the conceptual design study of experimental facilities required for applications of spallation neutrons and secondary particle beams. The Special Task Force for Neutron Science Initiative was established in May 1996 to promote aggressively and systematically the Neutron Science Research Program. The second workshop on neutron science research program was held at the JAERI Tokai Research Establishment on 13 and 14 March 1997 for the purpose of discussing the results obtained since the first workshop in March 1996. The 27 of the presented papers are indexed individually. (J.P.N.)

  11. Neutron Capture Experiments Using the DANCE Array at Los Alamos

    Science.gov (United States)

    Dashdorj, D.; Mitchell, G. E.; Baramsai, B.; Chyzh, A.; Walker, C.; Agvaanluvsan, U.; Becker, J. A.; Parker, W.; Sleaford, B.; Wu, C. Y.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Krtička, M.; Bečvář, F.

    2009-03-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) is designed for neutron capture measurements on very small and/or radioactive targets. The DANCE array of 160 BaF2 scintillation detectors is located at the Lujan Center at the Los Alamos Neutron Science Center (LANSCE). Accurate measurements of neutron capture data are important for many current applications as well as for basic understanding of neutron capture. The gamma rays following neutron capture reactions have been studied by the time-of-flight technique using the DANCE array. The high granularity of the array allows measurements of the gamma-ray multiplicity. The gamma-ray multiplicities and energy spectra for different multiplicities can be measured and analyzed for spin and parity determination of the resolved resonances.

  12. LENS-a pulsed neutron source for education and research

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, David V. [Physics Department, Indiana University, Bloomington, IN 47405 (United States)]. E-mail: baxterd@indiana.edu; Cameron, J.M. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Leuschner, M.B. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Meyer, H.O. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Nann, H. [Physics Department, Indiana University, Bloomington, IN 47405 (United States); Snow, W.M. [Physics Department, Indiana University, Bloomington, IN 47405 (United States)

    2005-04-21

    At the Indiana University Cyclotron Facility construction of a new source of cold neutrons has begun. Neutrons are generated by stopping 13 MeV protons in a beryllium target, located at the center of a moderator structure. Cold neutrons are emitted from a slab of frozen methane. Three beam lines deliver neutrons for scattering experiments, radiography and moderator studies. The purpose of the project is to develop a low-cost, small-scale facility, suitable for a university or an industrial setting, to provide a testing ground of instrumentation destined for use at a larger facility, to improve awareness of the use of neutron probes in a wide range of applications, and to offer a training opportunity for future neutron physicists.

  13. The second workshop of neutron science research program

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Hideshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tone, Tatsuzo [eds.

    1997-11-01

    The Japan Atomic Energy Research Institute(JAERI) has been proposing the Neutron Science Research Program to explore a broad range of basic research and the nuclear technology including actinide transmutation with use of powerful spallation neutron sources. For this purpose, the JAERI is conducting the research and development of an intense proton linac, the development of targets, as well as the conceptual design study of experimental facilities required for applications of spallation neutrons and secondary particle beams. The Special Task Force for Neutron Science Initiative was established in May 1996 to promote aggressively and systematically the Neutron Science Research Program. The second workshop on neutron science research program was held at the JAERI Tokai Research Establishment on 13 and 14 March 1997 for the purpose of discussing the results obtained since the first workshop in March 1996. The 27 of the presented papers are indexed individually. (J.P.N.)

  14. Development of advanced radiation monitors for pulsed neutron fields

    CERN Document Server

    AUTHOR|(CDS)2081895

    The need of radiation detectors capable of efficiently measuring in pulsed neutron fields is attracting widespread interest since the 60s. The efforts of the scientific community substantially increased in the last decade due to the increasing number of applications in which this radiation field is encountered. This is a major issue especially at particle accelerator facilities, where pulsed neutron fields are present because of beam losses at targets, collimators and beam dumps, and where the correct assessment of the intensity of the neutron fields is fundamental for radiation protection monitoring. LUPIN is a neutron detector that combines an innovative acquisition electronics based on logarithmic amplification of the collected current signal and a special technique used to derive the total number of detected neutron interactions, which has been specifically conceived to work in pulsed neutron fields. Due to its special working principle, it is capable of overcoming the typical saturation issues encountere...

  15. 5 MW pulsed spallation neutron source, Preconceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

  16. Ionization signals from diamond detectors in fast-neutron fields

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); CIVIDEC Instrumentation, Wien (Austria); Frais-Koelbl, H. [University of Applied Sciences, Wiener Neustadt (Austria); Griesmayer, E.; Kavrigin, P. [CIVIDEC Instrumentation, Wien (Austria); Vienna University of Technology, Wien (Austria)

    2016-09-15

    In this paper we introduce a novel analysis technique for measurements with single-crystal chemical vapor deposition (sCVD) diamond detectors in fast-neutron fields. This method exploits the unique electronic property of sCVD diamond sensors that the signal shape of the detector current is directly proportional to the initial ionization profile. In fast-neutron fields the diamond sensor acts simultaneously as target and sensor. The interaction of neutrons with the stable isotopes {sup 12}C and {sup 13}C is of interest for fast-neutron diagnostics. The measured signal shapes of detector current pulses are used to identify individual types of interactions in the diamond with the goal to select neutron-induced reactions in the diamond and to suppress neutron-induced background reactions as well as γ-background. The method is verified with experimental data from a measurement in a 14.3 MeV neutron beam at JRC-IRMM, Geel/Belgium, where the {sup 13}C(n, α){sup 10}Be reaction was successfully extracted from the dominating background of recoil protons and γ-rays and the energy resolution of the {sup 12}C(n, α){sup 9}Be reaction was substantially improved. The presented analysis technique is especially relevant for diagnostics in harsh radiation environments, like fission and fusion reactors. It allows to extract the neutron spectrum from the background, and is particularly applicable to neutron flux monitoring and neutron spectroscopy. (orig.)

  17. Ionization signals from diamond detectors in fast-neutron fields

    Science.gov (United States)

    Weiss, C.; Frais-Kölbl, H.; Griesmayer, E.; Kavrigin, P.

    2016-09-01

    In this paper we introduce a novel analysis technique for measurements with single-crystal chemical vapor deposition (sCVD) diamond detectors in fast-neutron fields. This method exploits the unique electronic property of sCVD diamond sensors that the signal shape of the detector current is directly proportional to the initial ionization profile. In fast-neutron fields the diamond sensor acts simultaneously as target and sensor. The interaction of neutrons with the stable isotopes 12 C and 13 C is of interest for fast-neutron diagnostics. The measured signal shapes of detector current pulses are used to identify individual types of interactions in the diamond with the goal to select neutron-induced reactions in the diamond and to suppress neutron-induced background reactions as well as γ-background. The method is verified with experimental data from a measurement in a 14.3 MeV neutron beam at JRC-IRMM, Geel/Belgium, where the 13C(n, α)10Be reaction was successfully extracted from the dominating background of recoil protons and γ-rays and the energy resolution of the 12C(n, α)9Be reaction was substantially improved. The presented analysis technique is especially relevant for diagnostics in harsh radiation environments, like fission and fusion reactors. It allows to extract the neutron spectrum from the background, and is particularly applicable to neutron flux monitoring and neutron spectroscopy.

  18. Overview of secondary neutron production relevant to shielding inspace

    Energy Technology Data Exchange (ETDEWEB)

    Heilbronn, L.; Nakamura, T.; Iwata, Y.; Kurosawa, T.; Iwase, H.; Townsend, L.W.

    2004-12-03

    An overview of experimental secondary neutron measurements relevant to space-related activities is presented. Stopping target yields and cross section measurements conducted at particle accelerators using heavy ions with energies >100 MeV per nucleon are discussed.

  19. Flux and Spectrum of Neutrons Generated from 25 Mv Medical X-Ray Therapy Machine

    Science.gov (United States)

    1989-05-01

    neutron absorption cross section at t. By using this relation in equation (1) the integration is possible over...0 n td f dat) n (it, rpLthprmQJ where 000 is defined as the microscopic neutron absorption cross - section at 2200 m/s, the most probable speed of a... neutron - absorption cross - section of the target as a function of energy O(E) is neutron flux per unit of energy as a function of energy. 1,d is

  20. Neutron scattering studies in the actinide region. Progress report, August 1, 1988--July 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Beghian, L.E.; Kegel, G.H.R.

    1991-08-01

    During the report period we have investigated the following areas: Neutron elastic and inelastic scattering measurements on {sup 14}N, {sup 181}Ta, {sup 232}Th, {sup 238}U and {sup 239}Pu; Prompt fission spectra for {sup 232}Th, {sup 235}U, {sup 238}U and {sup 239}Pu; Theoretical studies of neutron scattering; Neutron filters; New detector systems; and Upgrading of neutron target assembly, data acquisition system, and accelerator/beam-line apparatus.

  1. Neutrons and Fundamental Symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Plaster, Bradley [Univ. of Kentucky, Lexington, KY (United States). Dept. of Physics and Astronomy

    2016-01-11

    The research supported by this project addressed fundamental open physics questions via experiments with subatomic particles. In particular, neutrons constitute an especially ideal “laboratory” for fundamental physics tests, as their sensitivities to the four known forces of nature permit a broad range of tests of the so-called “Standard Model”, our current best physics model for the interactions of subatomic particles. Although the Standard Model has been a triumphant success for physics, it does not provide satisfactory answers to some of the most fundamental open questions in physics, such as: are there additional forces of nature beyond the gravitational, electromagnetic, weak nuclear, and strong nuclear forces?, or why does our universe consist of more matter than anti-matter? This project also contributed significantly to the training of the next generation of scientists, of considerable value to the public. Young scientists, ranging from undergraduate students to graduate students to post-doctoral researchers, made significant contributions to the work carried out under this project.

  2. Status of spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

  3. On the physical conditions for arising a controlled fusion chain reaction supported by neutrons in fusion facilities with magnetic plasma confinement

    Directory of Open Access Journals (Sweden)

    A.N. Shmelyov

    2015-11-01

    The fusion neutron source is considered to be the “richest”: neutron generation is accompanied by relatively small-scale processes. The thermonuclear facility with low neutron absorption blanket under consideration here could create a high density neutron flux in the blanket. It can be concluded from the above that such thermonuclear facilities could be used for fast transmutation of long-lived fission products with low neutron absorption cross-section, and perhaps even without their preliminary isotopic separation.

  4. Measurement of neutron-induced activation cross-sections using spallation source at JINR and neutronic validation of the Dubna code

    Indian Academy of Sciences (India)

    Manish Sharma; V Kumar; H Kumawat; J Adam; V S Barashenkov; S Ganesan; S Golovatiouk; S K Gupta; S Kailas; M I Krivopustov; H S Palsania; V Pronskikh; V M Tsoupko-Sitnikov; N Vladimirova; H Westmeier; W Westmeier

    2007-02-01

    A beam of 1 GeV proton coming from Dubna Nuclotron colliding with a lead target surrounded by 6 cm paraffin produces spallation neutrons. A Th-foil was kept on lead target (neutron spallation source) in a direct stream of neutrons for activation and other samples of 197Au, 209Bi, 59Co, 115In and 181Ta were irradiated by moderated beam of neutrons passing through 6 cm paraffin moderator. The gamma spectra of irradiated samples were analyzed using gamma spectrometry and DEIMOS software to measure the neutron cross-section. For this purpose neutron fluence at the positions of samples is also estimated using PREPRO software. The results of cross-sections for reactions 232Th(, ), 232Th(, 2), 197Au(, ), 197Au(, ), 197Au(, ), 59Co(, ), 59Co(, ), 181Ta(, ) and 181Ta(, ) are given in this paper. Neutronics validation of the Dubna Cascade Code is also done using cross-section data by other experiments.

  5. An overview of an accelerator-based neutron spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Lessner, E.S.

    1996-06-01

    An overview of the feasibility study of a 1-MW pulsed spallation source is presented. The machine delivers 1 MW of proton beam power to spallation targets where slow neutrons are produced. The slow neutrons can be used for isotope production, materials irradiation, and neutron scattering research. The neutron source facility is based on a rapid cycling synchrotron (RCS) and consists of a 400-MeV linac, a 30-Hz RCS that accelerates the 400-MeV beam to 2 GeV, and two neutron-generating target stations. The RCS accelerates an average proton beam current of 0.5 mA, corresponding to 1.04 x 10{sup 14} protons per pulse. This intensity is about two times higher than that of existing machines. A key feature of this accelerator system design is that beam losses are minimized from injection to extraction, reducing activation to levels consistent with hands-on maintenance.

  6. Neutron capture reactions on Lu isotopes at DANCE

    Directory of Open Access Journals (Sweden)

    Wouters J.M.

    2010-03-01

    Full Text Available The DANCE (Detector for Advanced Neutron Capture Experiments array located at the Los Alamos national laboratory has been used to obtain the neutron capture cross sections for the 175Lu and 176Lu isotopes with neutron energies from thermal up to 100 keV. Both isotopes are of current interest for the nucleosynthesis s-process in astrophysics and for applications as in reactor physics or in nuclear medicine. Three targets were used to perform these measurements. One was natLu foil and the other two were isotope-enriched targets of 175Lu and 176Lu. The cross sections are obtained for now through a precise neutron flux determination and a normalization at the thermal neutron cross section value. A comparison with the recent experimental data and the evaluated data of ENDF/B-VII.0 will be presented. In addition, resonances parameters and spin assignments for some resonances will be featured.

  7. Los Alamos Neutron Science Center (LANSCE) Nuclear Science Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Ronald Owen [Los Alamos National Laboratory; Wender, Steve [Los Alamos National Laboratory

    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.

  8. Characterization of compact accelerator DD neutron source for in situ calibration experiment on neutron measurement at LHD

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Yasunari; Iguchi, Tetsuo; Ogata, Tomohiro; Umemura, Norihiro; Asai, Keisuke; Kawarabayashi, Jun [Nagoya Univ., Nagoya, Aichi (Japan); Sasao, Mamiko [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2003-07-01

    A compact Cockcroft-Walton type accelerator DD neutron source has been developed for in situ calibration experiments on neutron measurements at LHD. The equipment mainly consists of three parts; a deuterium (D) reservoir/ion source, a self-loaded deuterium target and a 100 kV high voltage power supply, all of which are contained in a compact cylindrical stainless steel (SUS) tube of 70 mm in diameter and 780 mm in length. About one hour steady operation was performed under the acceleration voltage of 80 keV and the ion beam current of {approx}60 {mu}A, corresponding to the DD neutron yield of around 10{sup 5} n/s. The neutron emission profile and energy spectrum were measured with an NE213 scintillator and a {sup 3}He gas proportional counter. Preliminary neutronic calculations with a Monte Carlo neutron transport code MCNP' were also executed for simulating the in situ calibration experiment for neutron detectors that will be installed on LHD. Through the experiments and the calculations, it is shown that the present DD neutron source is valid for in situ calibration on threshold type detectors used for neutron emission profile monitoring and neutron spectrometry at DD plasma experiments. (author)

  9. Cooling of Accretion-Heated Neutron Stars

    Indian Academy of Sciences (India)

    Rudy Wijnands; Nathalie Degenaar; Dany Page

    2017-09-01

    We present a brief, observational review about the study of the cooling behaviour of accretion-heated neutron stars and the inferences about the neutron-star crust and core that have been obtained from these studies. Accretion of matter during outbursts can heat the crust out of thermal equilibrium with the core and after the accretion episodes are over, the crust will cool down until crust-core equilibrium is restored. We discuss the observed properties of the crust cooling sources and what has been learned about the physics of neutron-star crusts. We also briefly discuss those systems that have been observed long after their outbursts were over, i.e, during times when the crust and core are expected to be in thermal equilibrium. The surface temperature is then a direct probe for the core temperature. By comparing the expected temperatures based on estimates of the accretion history of the targets with the observed ones, the physics of neutron-star cores can be investigated. Finally, we discuss similar studies performed for strongly magnetized neutron stars in which the magnetic field might play an important role in the heating and cooling of the neutron stars.

  10. High-Energy Neutron Backgrounds for Underground Dark Matter Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Syracuse Univ., NY (United States)

    2016-01-01

    Direct dark matter detection experiments usually have excellent capability to distinguish nuclear recoils, expected interactions with Weakly Interacting Massive Particle (WIMP) dark matter, and electronic recoils, so that they can efficiently reject background events such as gamma-rays and charged particles. However, both WIMPs and neutrons can induce nuclear recoils. Neutrons are then the most crucial background for direct dark matter detection. It is important to understand and account for all sources of neutron backgrounds when claiming a discovery of dark matter detection or reporting limits on the WIMP-nucleon cross section. One type of neutron background that is not well understood is the cosmogenic neutrons from muons interacting with the underground cavern rock and materials surrounding a dark matter detector. The Neutron Multiplicity Meter (NMM) is a water Cherenkov detector capable of measuring the cosmogenic neutron flux at the Soudan Underground Laboratory, which has an overburden of 2090 meters water equivalent. The NMM consists of two 2.2-tonne gadolinium-doped water tanks situated atop a 20-tonne lead target. It detects a high-energy (>~ 50 MeV) neutron via moderation and capture of the multiple secondary neutrons released when the former interacts in the lead target. The multiplicity of secondary neutrons for the high-energy neutron provides a benchmark for comparison to the current Monte Carlo predictions. Combining with the Monte Carlo simulation, the muon-induced high-energy neutron flux above 50 MeV is measured to be (1.3 ± 0.2) ~ 10-9 cm-2s-1, in reasonable agreement with the model prediction. The measured multiplicity spectrum agrees well with that of Monte Carlo simulation for multiplicity below 10, but shows an excess of approximately a factor of three over Monte Carlo prediction for multiplicities ~ 10 - 20. In an effort to reduce neutron backgrounds for the dark matter experiment SuperCDMS SNO- LAB, an active neutron veto was developed

  11. Neutron spectrometry at JET (1983-1999)

    CERN Document Server

    Jarvis, O N

    2002-01-01

    An account is given of the neutron spectrometric measurements on tokamak plasmas that have been performed at the Joint European Torus (JET) Joint Undertaking. The original restrictions for physical access to the tokamak and the performance projections are described. The actual characteristics of JET plasmas as intense but highly transient sources of neutrons are then presented. Next, the various neutron spectrometers that have been deployed at JET are listed and their success in meeting the demands of the JET experiment is appraised. Finally, there is a discussion of the plasma physics considerations that determine the detailed shapes of the d-d and d-t spectral lines under the various plasma conditions and spectrometer viewing directions and of the results obtained.

  12. Neutron Source from Laser Plasma Acceleration

    Science.gov (United States)

    Jiao, Xuejing; Shaw, Joseph; McCary, Eddie; Downer, Mike; Hegelich, Bjorn

    2016-10-01

    Laser driven electron beams and ion beams were utilized to produce neutron sources via different mechanism. On the Texas Petawatt laser, deuterized plastic, gold and DLC foil targets of varying thickness were shot with 150 J , 150 fs laser pulses at a peak intensity of 2 ×1021W /cm2 . Ions were accelerated by either target normal sheath acceleration or Breakout Afterburner acceleration. Neutrons were produced via the 9Be(d,n) and 9Be(p,n) reactions when accelerated ions impinged on a Beryllium converter as well as by deuteron breakup reactions. We observed 2 ×1010 neutron per shot in average, corresponding to 5 ×1018n /s . The efficiencies for different targets are comparable. In another experiment, 38fs , 0.3 J UT3 laser pulse interacted with mixed gas target. Electrons with energy 40MeV were produced via laser wakefield acceleration. Neutron flux of 2 ×106 per shot was generated through bremsstrahlung and subsequent photoneutron reactions on a Copper converter.

  13. Neutron production by neutral beam sources

    Energy Technology Data Exchange (ETDEWEB)

    Berkner, K.H.; Massoletti, D.J.; McCaslin, J.B.; Pyle, R.V.; Ruby, L.

    1979-11-01

    Neutron yields, from interactions of multiampere 40- to 120-keV deuterium beams with deuterium atoms implanted in copper targets, have been measured in order to provide input data for shielding of neutral-deuterium beam facilities for magnetic fusion experiments.

  14. Neutron sources and applications

    Energy Technology Data Exchange (ETDEWEB)

    Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1994-01-01

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

  15. Prototype Stilbene Neutron Collar

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shumaker, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Verbeke, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wong, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceeds the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.

  16. Accelerator Based Neutron Beams for Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    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

  17. The Use of Fast Neutron Detection for Materials Accountability

    Science.gov (United States)

    Nakae, L. F.; Chapline, G. F.; Glenn, A. M.; Kerr, P. L.; Kim, K. S.; Ouedraogo, S. A.; Prasad, M. K.; Sheets, S. A.; Snyderman, N. J.; Verbeke, J. M.; Wurtz, R. E.

    2014-02-01

    For many years at LLNL, we have been developing time-correlated neutron detection techniques and algorithms for applications such as Arms Control, Threat Detection and Nuclear Material Assay. Many of our techniques have been developed specifically for the relatively low efficiency (a few percent) inherent in man-portable systems. Historically, thermal neutron detectors (mainly 3He) were used, taking advantage of the high thermal neutron interaction cross-sections, but more recently we have been investigating the use of fast neutron detection with liquid scintillators, inorganic crystals, and in the near future, pulse-shape discriminating plastics that respond over 1000 times faster (nanoseconds versus tens of microseconds) than thermal neutron detectors. Fast neutron detection offers considerable advantages, since the inherent nanosecond production timescales of fission and neutron-induced fission are preserved and measured instead of being lost in the thermalization of thermal neutron detectors. We are now applying fast neutron technology to the safeguards regime in the form of high efficiency counters. Faster detector response times and sensitivity to neutron momentum show promise in measuring, differentiating, and assaying samples that have modest to very high count rates, as well as mixed neutron sources (e.g., Pu oxide or Mixed Cm and Pu). Here we report on measured results with our existing liquid scintillator array and promote the design of a nuclear material assay system that incorporates fast neutron detection, including the surprising result that fast liquid scintillator becomes competitive and even surpasses the precision of 3He counters measuring correlated pairs in modest (kg) samples of plutonium.

  18. An intense 14 MeV neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Su Tongling; Sun Biehe; Yang Baotai; Piao Yubo; Shui Yongqing; Chen Kefan; Wang Xuezhi; Yang Cheng; Niu Zhanqi; Liu Yanton; Pan Minshen; Hong Zhongti; Chen Qin (Lanzhou Univ., GS (China). Inst. of Nuclear Research)

    1990-02-15

    A 3x10{sup 12} n/s source of 14 MeV neutrons is described in this paper. The neutrons are produced by the T(d,n){sup 4}He reaction under a 30 mA, 300 keV deuteron beam bombarding a water-cooled, rotating titanium-tritide target. The size of the beam spot on the target is 1.8 cm, and at the distance of closest approach to the source a neutron flux of 5x10{sup 11} n/cm{sup 2} s is obtained. (orig.).

  19. Recent developments on micrometric fission chambers for high neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Letourneau, A. [Irfu, Service de Physique Nucleaire, CEA-Saclay, 91191 Gif-sur-Yvette (France); Bringer, O.; Dupont, E.; Marie, F.; Panebianco, S.; Toussaint, J. C.; Veyssiere, C. [Irfu, CEA-Saclay, 91191 Gif-sur-Yvette (France); Chabod, S. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3 (France); Breaud, S.; Oriol, L. [DEN/DER/SPEX, CEA-Cadarache, Saint-Paul-lez-Durances (France)

    2009-07-01

    With the development of innovative nuclear systems and new generation neutron sources, the nuclear instrumentation should be adapted. Since several years, we developed microscopic fission chambers to study the transmutation of minor actinides in high thermal-neutron fluxes. The recent developments done to fulfill the drastic conditions of irradiations are described in this paper together with the feedback from the measurements. Two installations were used: the HFR of the ILL for its highest thermal neutron flux of the world and the MEGAPIE target which was the first 1 MW liquid Pb-Bi spallation target in the world. (authors)

  20. The DIORAMA Neutron Emitter

    Energy Technology Data Exchange (ETDEWEB)

    Terry, James Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    Emission of neutrons in a given event is modeled by the DioramaEmitterNeutron object, a subclass of the abstract DioramaEmitterModule object. The GenerateEmission method of this object is the entry point for generation of a neutron population for a given event. Shown in table 1, this method requires a number of parameters to be defined in the event definition.

  1. The first neutron beam hits EAR2

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    On 25 July 2014, about a year after construction work began, the Experimental Area 2 (EAR2) of CERN’s neutron facility n_TOF recorded its first beam. Unique in many aspects, EAR2 will start its rich programme of experimental physics this autumn.   The last part of the EAR2 beamline: the neutrons come from the underground target and reach the top of the beamline, where they hit the samples. Built about 20 metres above the neutron production target, EAR2 is in fact a bunker connected to the n_TOF underground facilities via a duct 80 cm in diameter, where the beamline is installed. The feet of the bunker support pillars are located on the concrete structure of the n_TOF tunnel and part of the structure lies above the old ISR building. A beam dump located on the roof of the building completes the structure. Neutrons are used by physicists to study neutron-induced reactions with applications in a number of fields, including nuclear waste transmutation, nuclear technology, nuclear astrop...

  2. CERN’s neutrons fly higher

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    The construction of a second experimental area for n_TOF – CERN’s neutron source – has just been approved by the CERN Council. The new facility will provide the scientific community with a higher neutron flux, which translates into a higher sensitivity for the experiments. The new neutron beam line will open the way to a wider variety of research fields including nuclear energy applications, nuclear astrophysics, basic nuclear physics, dosimetry and radiation damage.   The 4π calorimeter inside the n_TOF experimental area. Image courtesy of the n_TOF Collaboration. The project involves building a vertical flight path roughly 20 m above the current neutron target and a new experimental hall – Experimental Area 2 (EAR-2) – in the current Building 559. EAR-2 will be located on top of the neutron production target and partially on top of the ISR building (see the image below of a model of the facility). “The hall will be housed i...

  3. Nuclear Waste Transmutation in Subcritical Reactors Driven by Target-Distributed Accelerators

    CERN Document Server

    Blanovsky, A

    2004-01-01

    A radioactive waste transmutation system based extensively on existing nuclear power technology is presented. By replacing the control rods with neutron sources, we could maintain good power distribution and perform long-lived waste burning in high flux subcritical reactors. The design is based on a small pressurized water reactor, fission electric cell (FEC), target-distributed accelerator (TDA) and power monitoring system with in-core gamma-ray detectors, now under development in several countries. The TDA, in which an FEC electric field compensates for lost beam energy in the target, offers a new approach to obtain large neutron fluxes. The analysis takes into consideration a wide range of TDA design aspects including the wave model of observed relativistic phenomena, in-core microwave power source, the FEC with a multistage collector (anode) and layered cathode.

  4. Applications of an Y-88/Be photo-neutron calibration source to Dark Matter and Neutrino Experiments

    CERN Document Server

    Collar, J I

    2013-01-01

    The low-energy monochromatic neutron emission from an Y-88/Be source can be exploited to mimic the few keVnr nuclear recoils expected from low-mass Weakly Interacting Massive Particles (WIMPs) and coherent scattering of neutrinos off nuclei. Using this source, a ~<10% quenching factor is measured for sodium recoils below 24 keVnr in NaI[Tl]. This is considerably smaller than the 30% typically adopted in the interpretation of the DAMA/LIBRA dark matter experiment, resulting in an increase of its tension with other negative searches. The method is illustrated for other target materials (superheated and noble liquids).

  5. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Science.gov (United States)

    Skalyga, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Maslennikova, A.; Volovecky, A.; Kalvas, T.; Koivisto, H.; Tarvainen, O.

    2014-12-01

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·1010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, C.; Fallin, B. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Gooden, M.E., E-mail: megooden@tunl.duke.edu [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Howell, C.R. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Kelley, J.H. [Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Department of Physics, North Carolina State University, Raleigh, NC 27605 (United States); Tornow, W. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); 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. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Becker, J.A.; Macri, R.; Ryan, C.; Sheets, S.A.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); and others

    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.

  7. Neutron beam line design of a white neutron source at CSNS

    Science.gov (United States)

    Jing, Hantao; Zhang, Liying; Tang, Jingyu; Ruan, Xichao; Ning, Changjun; Yu, Yongji; Wang, Pengcheng; Li, Qiang; Ren, Jie; Tang, Hongqing; Wang, Xiangqi

    2017-09-01

    China Spallation Neutron Source (CSNS), which is under construction, is a large scientific facility dedicated mainly for multi-disciplinary research on material characterization using neutron scattering techniques. The CSNS Phase-I accelerator will deliver a proton beam with an energy of 1.6 GeV and a pulse repetition rate of 25 Hz to a tungsten target, and the beam power is 100 kW. A white neutron source using the back-streaming neutrons through the incoming proton beam channel was proposed and is under construction. The back-streaming neutrons which are very intense and have good time structure are very suitable for nuclear data measurements. The white neutron source includes an 80-m neutron beam line, two experimental halls, and also six different types of spectrometers. The physics design of the beam line is presented in this paper, which includes beam optics and beam characterization simulations, with the emphasis on obtaining extremely low background. The first-batch experiments on nuclear data measurements are expected to be conducted in late 2017.

  8. Optimizing moderator dimensions for neutron scattering at the spallation neutron source.

    Science.gov (United States)

    Zhao, J K; Robertson, J L; Herwig, Kenneth W; Gallmeier, Franz X; Riemer, Bernard W

    2013-12-01

    In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter).

  9. Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Skalyga, V., E-mail: skalyga.vadim@gmail.com [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Izotov, I.; Golubev, S.; Razin, S. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Sidorov, A. [Institute of Applied Physics, RAS, 46 Ul’yanova st., 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Maslennikova, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State Medical Academy, 10/1 Minina Sq., 603005 Nizhny Novgorod (Russian Federation); Volovecky, A. [Lobachevsky State University of Nizhny Novgorod (UNN), 23 Gagarina st., 603950 Nizhny Novgorod (Russian Federation); Kalvas, T.; Koivisto, H.; Tarvainen, O. [University of Jyvaskyla, Department of Physics, PO Box 35 (YFL), 40500 Jyväskylä (Finland)

    2014-12-21

    Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D–D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm{sup 2} is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 6·10{sup 10} cm{sup −2}/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

  10. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2014-07-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  11. Reusable shielding material for neutron- and gamma-radiation

    Science.gov (United States)

    Calzada, Elbio; Grünauer, Florian; Schillinger, Burkhard; Türck, Harald

    2011-09-01

    At neutron research facilities all around the world radiation shieldings are applied to reduce the background of neutron and gamma radiation as far as possible in order to perform high quality measurements and to fulfill the radiation protection requirements. The current approach with cement-based compounds has a number of shortcomings: "Heavy concrete" contains a high amount of elements, which are not desired to obtain a high attenuation of neutron and/or gamma radiation (e.g. calcium, carbon, oxygen, silicon and aluminum). A shielding material with a high density of desired nuclei such as iron, hydrogen and boron was developed for the redesign of the neutron radiography facility ANTARES at beam tube 4 (located at a cold neutron source) of FRM-II. The composition of the material was optimized by help of the Monte Carlo code MCNP5. With this shielding material a considerable higher attenuation of background radiation can be obtained compared to usual heavy concretes.

  12. Neutron stars structure in the context of massive gravity

    Science.gov (United States)

    Hendi, S. H.; Bordbar, G. H.; Eslam Panah, B.; Panahiyan, S.

    2017-07-01

    Motivated by the recent interests in spin-2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.

  13. Inertial electrostatic confinement I(IEC) neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Nebel, R.A.; Barnes, D.C.; Caramana, E.J.; Janssen, R.D.; Nystrom, W.D.; Tiouririne, T.N.; Trent, B.C. [Los Alamos National Lab., NM (United States); Miley, G.H.; Javedani, J. [Illinois Univ., Urbana, IL (United States)

    1995-12-01

    Inertial Electrostatic Confinement (IEC) is one of the earliest plasma confinement concepts, having first been suggested by P.T. Farnsworth in the 1950s. The concept involves a simple apparatus of concentric spherical electrostatic grids or a combination of grids and magnetic fields. An electrostatic structure is formed from the confluence of electron or ion beams. Gridded IEC systems have demonstrated neutron yields as high as 2*10 [10]. neutrons/sec in steady state. These systems have considerable potential as small, inexpensive, portable neutron sources for assaying applications. Neutron tomography is also a potential application. This paper discusses the IEC concept and how it can be adapted to a steady-state assaying source and an intense pulsed neutron source. Theoretical modeling and experimental results are presented.

  14. Preliminary Status Report of Neutron Radiation Effects and Damage to Neutron Imaging System Equipment at Lawrence Livermore National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Bleuel, D. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Anderson, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bernstein, L. A. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brand, C. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brown, J. A. [Univ. of California, Berkeley, CA (United States); Caggiano, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); FItsos, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Goldblum, B. L. [Univ. of California, Berkeley, CA (United States); Hall, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Harrig, K. P. [Univ. of California, Berkeley, CA (United States); Johnson, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kruse, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Laplace, T. A. [Univ. of California, Berkeley, CA (United States); Mahowald, M. [Univ. of California, Berkeley, CA (United States); Matthews, E. [Univ. of California, Berkeley, CA (United States); Nielson, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United S