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Sample records for neutrons target considerations

  1. Materials considerations for the National Spallation Neutron Source target

    International Nuclear Information System (INIS)

    Mansur, L.K.; DiStefano, J.R.; Farrell, K.; Lee, E.H.; Pawel, S.J.; Wechsler, M.S.

    1997-08-01

    The National Spallation Neutron Source (NSNS), in which neutrons are generated by bombarding a liquid mercury target with 1 GeV protons, will place extraordinary demands on materials performance. The target structural material will operate in an aggressive environment, subject to intense fluxes of high energy protons, neutrons, and other particles, while exposed to liquid mercury and to water. Components that require special consideration include the Hg liquid target container and protective shroud, beam windows, support structures, moderator containers, and beam tubes. In response to these demands a materials R and D program has been developed for the NSNS that includes: selection of materials; calculations of radiation damage; irradiations, post irradiation testing, and characterization; compatibility testing and characterization; design and implementation of a plan for monitoring of materials performance in service; and materials engineering and technical support to the project. Irradiations are being carried out in actual and simulated spallation environments. Compatibility experiments in Hg are underway to ascertain whether the phenomena of liquid metal embrittlement and temperature gradient mass transfer will be significant. Results available to date are assessed in terms of the design and operational performance of the facility

  2. Conceptual design considerations and neutronics of lithium fall laser fusion target chambers

    International Nuclear Information System (INIS)

    Meier, W.R.; Thomson, W.B.

    1978-01-01

    Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage

  3. Conceptual design considerations and neutronics of lithium fall laser target chambers

    International Nuclear Information System (INIS)

    Meier, W.R.; Thomson, W.B.

    1978-01-01

    Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage

  4. Materials considerations in accelerator targets

    International Nuclear Information System (INIS)

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

    1995-01-01

    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

  5. Materials considerations in accelerator targets

    International Nuclear Information System (INIS)

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

    1994-01-01

    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. 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 the manufacturing technologies evaluated and presents the model for tritium retention in aluminum clad, aluminum-lithium alloy tritium production targets

  6. Structural integrity of heavy liquid-metal target installed in spallation neutron facility. Part 4: Consideration by fracture mechanics of target container window

    International Nuclear Information System (INIS)

    Ishikura, Syuichi; Kogawa, Hiroyuki; Futakawa, Masatoshi; Kikuchi, Kenji; Haga, Katsuhiro; Kaminaga, Masanori; Hino, Ryutaro

    2004-01-01

    Developments of the neutron scattering facility is carried out under the high-intensity proton accelerator project promoted by JAERI and KEK. To estimate the structural integrity of the heavy liquid-metal (mercury) target used as a spallation neutron source in a MW-class neutron scattering facility, static and dynamic stress (including pressure wave in mercury) behaviors due to the incident of 1MW-pulsed proton beam (Maximum heat density is 461W/cc) were analyzed. In the analyses, two type target containers with semi-cylindrical type and flat-type beam windows were used as analytical models. As a result, it is confirmed that the stress generated by the pressure wave becomes the largest at the center of the beam window, and the flat-type beam window is more advantageous from the structural viewpoint than the semi-cylindrical type beam window. It has been understood that the stress generated in the beam window by the pressure wave can be treated as the secondary stress. Then, it has been understood that the stress and the stress range generated in the target window were bellow the allowable stress level defined by the standard of JIS on the maximum stress and fatigue strength. It has been experimentally confirmed that a cavitation was generated by generating the negative pressure in mercury near the target beam window and a collapse of cavitation damaged to the target container material, as pits. Then, the fracture mechanical analyses were carried out on the pit and a crack on pit tip. Consequently, it was clarified that the crack would not propagate because the inner surface of the beam window was become the compressive stress field due to the steady state thermal stress. Moreover, the evaluation technique of the cavitation which would be needed in the future was summarized. (author)

  7. Delayed neutrons in liquid metal spallation targets

    International Nuclear Information System (INIS)

    Ridikas, D.; Bokov, P.; David, J.C.; Dore, D.; Giacri, M.L.; Van Lauwe, A.; Plukiene, R.; Plukis, A.; Ignatiev, S.; Pankratov, D.

    2003-01-01

    The next generation spallation neutron sources, neutrino factories or RIB production facilities currently being designed and constructed around the world will increase the average proton beam power on target by a few orders of magnitude. Increased proton beam power results in target thermal hydraulic issues leading to new target designs, very often based on flowing liquid metal targets such as Hg, Pb, Pb-Bi. Radioactive nuclides produced in liquid metal targets are transported into hot cells, past electronics, into pumps with radiation sensitive components, etc. Besides the considerable amount of photon activity in the irradiated liquid metal, a significant amount of the delayed neutron precursor activity can be accumulated in the target fluid. The transit time from the front of a liquid metal target into areas, where delayed neutrons may be important, can be as short as a few seconds, well within one half-life of many delayed neutron precursors. Therefore, it is necessary to evaluate the total neutron flux (including delayed neutrons) as a function of time and determine if delayed neutrons contribute significantly to the dose rate. In this study the multi-particle transport code MCNPX combined with the material evolution program CINDER'90 will be used to evaluate the delayed neutron flux and spectra. The following scientific issues will be addressed in this paper: - Modeling of a typical geometry of the liquid metal spallation target; - Predictions of the prompt neutron fluxes, fission fragment and spallation product distributions; - Comparison of the above parameters with existing experimental data; - Time-dependent calculations of delayed neutron precursors; - Neutron flux estimates due to the prompt and delayed neutron emission; - Proposal of an experimental program to measure delayed neutron spectra from high energy spallation-fission reactions. The results of this study should be directly applicable in the design study of the European MegaPie (1 MW

  8. Spallation source neutron target systems

    International Nuclear Information System (INIS)

    Russell, G.; Brown, R.; Collier, M.; Donahue, J.

    1996-01-01

    This is the final report for a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project sought to design a next-generation spallation source neutron target system for the Manuel Lujan, Jr., Neutron Scattering Center (LANSCE) at Los Alamos. It has been recognized for some time that new advanced neutron sources are needed in the US if the country is to maintain a competitive position in several important scientific and technological areas. A recent DOE panel concluded that the proposed Advanced Neutron Source (a nuclear reactor at Oak Ridge National Laboratory) and a high-power pulsed spallation source are both needed in the near future. One of the most technically challenging designs for a spallation source is the target station itself and, more specifically, the target-moderator-reflector arrangement. Los Alamos has demonstrated capabilities in designing, building, and operating high-power spallation-neutron-source target stations. Most of the new design ideas proposed worldwide for target system design for the next generation pulsed spallation source have either been conceived and implemented at LANSCE or proposed by LANSCE target system designers. These concepts include split targets, flux-trap moderators, back scattering and composite moderators, and composite reflectors

  9. Some considerations on stochastic neutron populations (u)

    International Nuclear Information System (INIS)

    Souto, Francisco J.; Prinja, Anil K.

    2010-01-01

    The neutron population in a multiplying body containing a weak random source may depart considerably from its average or expected value. The resulting behavior of the system is then unpredictable and a fully stochastic description of the neutron population becomes necessary. Stochastic considerations are especially important when dealing with pulsed reactors or in the case of criticality excursions in the presence of a weak source. Using the theory of discrete-state continuous-time Markov processes, and subject to some physical approximations, Bell (I) obtained approximate solutions for the neutron number probability distributions (pdf), with and without an intrinsic rapdom neutron source, that were valid at late times and/ large neutron populations. In recent work (4), we obtained exact solutions for Bell's model problem, and in this paper we use these exact probability distributions to: (I) assess the accuracy of Bell's asymptotic solutions and show how the latter follow from the exact solutions, (2) rigorously examine the probability of obtaining a divergent chain reaction, and (3) demonstrate the existence of an abrupt transition from a stochastic to a deterministic phase with increasing source strength.

  10. Jet target intense neutron source

    International Nuclear Information System (INIS)

    Meier, K.L.

    1977-01-01

    A jet target Intense Neutron Source (INS) is being built by the Los Alamos Scientific Laboratory with DOE/MFE funding in order to perform radiation damage experiments on materials to be used in fusion power reactors. The jet target can be either a supersonic or a subsonic jet. Each type has its particular advantages and disadvantages, and either of the jets can be placed inside the spherical blanket converter which will be used to simulate a fusion reactor neutron environment. Preliminary mock-up experiments with a 16-mA, 115 keV, H + ion beam on a nitrogen gas supersonic jet show no serious problems in the beam formation, transport, or jet interaction

  11. Gas target neutron generator studies

    International Nuclear Information System (INIS)

    Chatoorgoon, V.

    1978-01-01

    The need for an intense neutron source for the study of radiation damage on materials has resulted in the proposal of various solid, liquid, and gas targets. Among the gas targets proposed have been the transonic gas target, two types of hypersonic gas target, and the subsonic gas target (SGT). It has been suggested that heat deposition in a subsonic channel might create a gas density step which would constitute an attractive gas target type. The first part of the present study examines this aspect of the SGT and shows that gas density gradients are indeed formed by heat deposition in subsonic flow. The variation of beam voltage, gas density, gas pressure, and gas temperature within the channel have been calculated as functions of the system parameters: beam voltage, beam current, channel diameter, stagnation tank temperature and pressure. The analysis is applicable to any beam particle and target gas. For the case of T + on D 2 , which is relevant to the fusion application, the 14 MeV neutron profiles are presented as a function of system parameters. It is found that the SGT is compatible with concentrated intense source operation. The possibility of instability was investigated in detail using a non-linear analysis which made it possible to follow the complete time development of the SGT. It was found that the SGT is stable against all small perturbations and certain types of large perturbations. It appears that the SGT is the most advantageous type of gas target, operating at a lower mass flow and less severe stagnation tank conditions than the other types. The second part of the thesis examines a problem associated with the straight hypersonic target, the deuterium spill into the tritium port. The regime of practical operation for this target is established. (auth)

  12. Considerations for boron neutron capture therapy studies

    International Nuclear Information System (INIS)

    Faria Gaspar, P. de.

    1994-01-01

    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

  13. Target system neutronics study for NXGENS

    International Nuclear Information System (INIS)

    Willis, C.; Muhrer, G.

    2007-01-01

    The Materials Test Station (MTS) [E. Pitcher, G. Muhrer, H. Trellue, Neutronics Assessment of the LANSCE Materials Test Station as an Irradiation Facility for the JIMO Space Reactor, LA-CP-04-0903.], a spallation target station, planned for construction at the Los Alamos Neutron Science Center (LANSCE), will provide the opportunity to test the prototype of a long-pulse spallation source neutron scattering instrument (NXGENS). In this paper, we present the target-moderator neutronics optimization study that was performed in support of NXGENS

  14. Neutron personnel dosimetry considerations for fusion reactors

    International Nuclear Information System (INIS)

    Barton, T.P.; Easterly, C.E.

    1979-07-01

    The increasing development of fusion reactor technology warrants an evaluation of personnel neutron dosimetry systems to aid in the concurrent development of a radiation protection program. For this reason, current state of knowledge neutron dosimeters have been reviewed with emphasis placed on practical utilization and the problems inherent in each type of dosimetry system. Evaluations of salient parameters such as energy response, latent image instability, and minimum detectable dose equivalent are presented for nuclear emulsion films, track etch techniques, albedo and other thermoluminescent dosimetry techniques, electrical conductivity damage effects, lyoluminescence, thermocurrent, and thermally stimulated exoelectron emission. Brief summaries of dosimetry regulatory requirements and intercomparison study results help to establish compliance and recent trends, respectively. Spectrum modeling data generated by the Neutron Physics Division of Oak Ridge National Laboratory for the Princeton Tokamak Fusion Test Reactor (TFTR) Facility have been analyzed by both International Commission on Radiological Protection fluence to dose conversion factors and an adjoint technique of radiation dosimetry, in an attempt to determine the applicability of current neutron dosimetry systems to deuterium and tritium fusion reactor leakage spectra. Based on the modeling data, a wide range of neutron energies will probably be present in the leakage spectra of the TFTR facility, and no appreciable risk of somatic injury to occupationally exposed workers is expected. The relative dose contributions due to high energy and thermal neutrons indicate that neutron dosimetry will probably not be a serious limitation in the development of fusion power

  15. Spallation neutron source target station issues

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Barnes, J.N.; Charlton, L.A.

    1996-01-01

    In many areas of physics, materials and nuclear engineering, it is extremely valuable to have a very intense source of neutrons so that the structure and function of materials can be studied. One facility proposed for this purpose is the National Spallation Neutron Source (NSNS). This facility will consist of two parts: (1) a high-energy (∼1 GeV) and high powered (∼ 1 MW) proton accelerator, and (2) a target station which converts the protons to low-energy (≤ 2 eV) neutrons and delivers them to the neutron scattering instruments. This paper deals with the second part, i.e., the design and development of the NSNS target station and the scientifically challenging issues. Many scientific and technical disciplines are required to produce a successful target station. These include engineering, remote handling, neutronics, materials, thermal hydraulics, and instrumentation. Some of these areas will be discussed

  16. Neutron effects in humans: protection considerations

    International Nuclear Information System (INIS)

    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

  17. 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)

  18. 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....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

  19. Neutron performance analysis for ESS target proposal

    International Nuclear Information System (INIS)

    Magán, M.; Terrón, S.; Thomsen, K.; Sordo, F.; Perlado, J.M.; Bermejo, F.J.

    2012-01-01

    In the course of discussing different target types for their suitability in the European Spallation Source (ESS) one main focus was on neutronics' performance. Diverse concepts have been assessed baselining some preliminary engineering and geometrical details and including some optimization. With the restrictions and resulting uncertainty imposed by the lack of detailed designs optimizations at the time of compiling this paper, the conclusion drawn is basically that there is a little difference in the neutronic yield of the investigated targets. Other criteria like safety, environmental compatibility, reliability and cost will thus dominate the choice of an ESS target.

  20. Health physics considerations at a neutron therapy facility cyclotron

    International Nuclear Information System (INIS)

    Kleck, J.H.; Krueger, D.J.; Mc Laughlin, J.E.; Smathers, J.B.

    1987-01-01

    The U.C.L.A. Neutron Therapy Facility (NTF) is one of four such facilities in the United States currently involved in NCI sponsored trials of neutron therapy and reflects the present interest in the use of high energy neutron beams for treating certain types of human cancers. The NTF houses a CP-45 negative ion cyclotron which accelerates a 46 MeV proton beam for production of neutrons from a beryllium target. In addition to patient treatment, the NTF is involved in the production of positron emitting radioisotopes for diagnostic use in Positron Emission Tomography (PET). The activation of therapy treatment collimators, positron and neutron target systems, and a high and rapidly varying external radiation environment in a clinical setting have contributed to the need for a comprehensive radiation control program in which patient care is balanced with the maintenance of occupational exposures to ALARA levels

  1. Practical considerations in instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Ahmad, N.

    2001-01-01

    Activation analysis is a technique of elemental analysis based on the measurement of characteristics radiation from radionuclides formed directly or indirectly by activation. The activation can be induced by bombarding the material with neutrons or charged particles or gamma rays. This is a well-accepted analytical technique for the determination of composition of complex materials. This technique is also sensitive at trace levels and is almost free from analytical interferences of matrix. It is used for multi-elemental determination in rocks, minerals, alloys, biological materials, geological samples, non-destructive analysis of materials and environmental samples such as water, air particulate matter, plants, soil, sediments and diets. This method is also used for production and measurements of radioisotopes in materials of known composition, for example, when radioactivation is used for nuclear reaction studies, for flux and beam intensity measurements for trace experiments and process quality control. In this article the parameters affecting the sensitivity of instrumental neutron activation analysis are briefly discussed. (author)

  2. Targets for neutron beam spallation sources

    International Nuclear Information System (INIS)

    Bauer, G.S.

    1980-01-01

    The meeting on Targets for Neutron Beam Spallation Sources held at the Institut fuer Festkoerperforschung at KFA Juelich on June 11 and 12, 1979 was planned as an informal get-together for scientists involved in the planning, design and future use of spallation neutron sources in Europe. These proceedings contain the papers contributed to this meeting. For further information see hints under relevant topics. (orig./FKS)

  3. Large area solid target neutron source

    International Nuclear Information System (INIS)

    Crawford, J.C.; Bauer, W.

    1974-01-01

    A potentially useful neutron source may result from the combination of a solid deuterium-tritium loaded target with the large area, high energy ion beams from ion sources being developed for neutral beam injection. The resulting neutron source would have a large radiating area and thus produce the sizable experimental volume necessary for future studies of bulk and synergistic surface radiation effects as well as experiments on engineering samples and small components. With a 200 keV D + T + beam and 40 kW/cm 2 power dissipation on a 200 cm 2 target spot, a total neutron yield of about 4 x 10 15 n/sec may be achieved. Although the useable neutron flux from this source is limited to 1 to 2 x 10 13 n/cm 2 /sec, this flux can be produced 3 cm in front of the target and over about 300 cm 3 of experimental volume. Problems of total power dissipation, sputtering, isotopic flushing and thermal dissociation are reviewed. Neutron flux profiles and potential experimental configurations are presented and compared to other neutron source concepts. (U.S.)

  4. General considerations for neutron capture therapy at a reactor facility

    International Nuclear Information System (INIS)

    Binney, S.E.

    2001-01-01

    In addition to neutron beam intensity and quality, there are also a number of other significant criteria related to a nuclear reactor that contribute to a successful neutron capture therapy (NCT) facility. These criteria are classified into four main categories: Nuclear design factors, facility management and operations factors, facility resources, and non-technical factors. Important factors to consider are given for each of these categories. In addition to an adequate neutron beam intensity and quality, key requirements for a successful neutron capture therapy facility include necessary finances to construct or convert a facility for NCT, a capable medical staff to perform the NCT, and the administrative support for the facility. The absence of any one of these four factors seriously jeopardizes the overall probability of success of the facility. Thus nuclear reactor facility management considering becoming involved in neutron capture therapy, should it be proven clinically successful, should take all these factors into consideration. (author)

  5. Neutron polarization in polarized 3He targets

    International Nuclear Information System (INIS)

    Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

    1990-01-01

    Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

  6. Some neutron measurements with simulated ING targets

    International Nuclear Information System (INIS)

    Walker, J.

    1966-01-01

    Thermal neutron fluxes in the vicinity of a simulated Intense Neutron Generator target have been measured using Mn and Au foils, and a small BF 3 detector. The target was a Pb cylinder either 4-inch or 8-inch in diameter with a 1.2 g Ra-Be neutron source at its centre. This was centrally mounted in a 5' diam. x 5' high tank which was filled with either H 2 O or D 2 O moderator. Various gaps and absorbing annuli were placed around the target, and air-filled aluminum 'beam tubes' were mounted radially or tangentially from the target to simulate typical ING conditions. The measured thermal neutron fluxes were less than calculated at all radii. The single-age computation clearly gives large errors at large radii, but the multi-energy approach seems to give a useful indication of the thermal flux distribution in spite of the extreme simplicity of the model. The fall in measured fluxes at small radii in both D 2 O and H 2 O is most likely caused by absorption in the target material which is not allowed for in the computational model. (author)

  7. Some neutron measurements with simulated ING targets

    Energy Technology Data Exchange (ETDEWEB)

    Walker, J

    1966-07-01

    Thermal neutron fluxes in the vicinity of a simulated Intense Neutron Generator target have been measured using Mn and Au foils, and a small BF{sub 3} detector. The target was a Pb cylinder either 4-inch or 8-inch in diameter with a 1.2 g Ra-Be neutron source at its centre. This was centrally mounted in a 5' diam. x 5' high tank which was filled with either H{sub 2}O or D{sub 2}O moderator. Various gaps and absorbing annuli were placed around the target, and air-filled aluminum 'beam tubes' were mounted radially or tangentially from the target to simulate typical ING conditions. The measured thermal neutron fluxes were less than calculated at all radii. The single-age computation clearly gives large errors at large radii, but the multi-energy approach seems to give a useful indication of the thermal flux distribution in spite of the extreme simplicity of the model. The fall in measured fluxes at small radii in both D{sub 2}O and H{sub 2}O is most likely caused by absorption in the target material which is not allowed for in the computational model. (author)

  8. Neutron transport from targets to moderators

    International Nuclear Information System (INIS)

    Taylor, A.D.

    1980-01-01

    The title of this meeting is 'Targets for Neutron Beam Spallation Sources', but so far all the emphasis in the talks has been on how to produce the fast neutron flux. I would like to stress that that is just the beginning of the story. What we are required to produce are beams of thermal and epithermal neutrons with time and spectral characteristics tailored to the instrumental requirements. The real source of our neutrons is not uranium arrays or thorium cylinders but a small volume of hydrogenous material, some 10 x 10 x 5 cm 3 . This is really what the whole thing is about - the target produces a copious field of fast neutrons, but if we fail to moderate them with the right energy and time characteristics, we will not match to what is happening downstream. In this talk, I am going to deal specifically with what we have done for SNS to optimise the target-moderator-reflector and decoupler system in this respect. (orig.)

  9. The National Spallation Neutron Source Target Station.

    Science.gov (United States)

    Gabriel, T. A.

    1997-05-01

    The technologies that are being utilized to design and build a state-of-the-art high powered (>= 1 MW), short pulsed (storage ring. Many scientific and technical disciplines are required to produce a successful target station. These disciplines include engineering, remote handling, neutronics, materials, thermal hydraulics, shock analysis, etc. In the areas of engineering and remote handling special emphasis is being given to rapid and efficient assembly and disassembly of critical parts of the target station. In the neutronics area, emphasis is being given to neutron yield and pulse optimization from the moderators, and heating and activation rates throughout the station. Development of structural materials to withstand aggressive radiation environments and that are compatible with other materials is also an important area. Thermal hydraulics and shock analysis are being closely studied since large amounts of energy are being deposited in small volumes in relatively short time periods (< 1 μsec). These areas will be expanded upon in the paper.

  10. System design considerations for fast-neutron interrogation systems

    International Nuclear Information System (INIS)

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

    1993-01-01

    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

  11. Behavior of structural and target materials irradiated in spallation neutron environments

    International Nuclear Information System (INIS)

    Stubbins, J.F.; Wechsler, M.; Borden, M.

    1995-01-01

    This paper describes considerations for selection of structural and target materials for accelerator-driven neutron sources. Due to the operating constraints of proposed accelerator-driven neutron sources, the criteria for selection are different than those commonly applied to fission and fusion systems. Established irradiation performance of various alloy systems is taken into account in the selection criteria. Nevertheless, only limited materials performance data are available which specifically related to neutron energy spectra anticipated for spallation sources

  12. Behavior of structural and target materials irradiated in spallation neutron environments

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, J.F. [Univ. of Illinois, Urbana, IL (United States); Wechsler, M. [North Carolina State Univ., Raleigh, NC (United States); Borden, M. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-10-01

    This paper describes considerations for selection of structural and target materials for accelerator-driven neutron sources. Due to the operating constraints of proposed accelerator-driven neutron sources, the criteria for selection are different than those commonly applied to fission and fusion systems. Established irradiation performance of various alloy systems is taken into account in the selection criteria. Nevertheless, only limited materials performance data are available which specifically related to neutron energy spectra anticipated for spallation sources.

  13. EURAC: A liquid target neutron spallation

    Energy Technology Data Exchange (ETDEWEB)

    Perlado, J.M.; Minguez, E.; Sanz, J. [Universidad Politecnica de Madrid (Spain)] [and others

    1995-10-01

    Euratom/JRC Ispra led some years ago the design of an accelerator based neutron spallation source EURAC, with special emphasis as a fusion material testing device. DENIM was involved in the development of the last version of this source. EURAC proposes to use a beam of 600 MeV or 1.5 GeV protons, produced by an effective and low cost ring cyclotron with a current of 6 mA impinging in a liquid lead, or lead-bismuth, target. It will use an advanced cyclotron technology which can be implemented in the next future, in the line of the actual technology of the upgraded SIN-type cyclotron. The adjacent rows to the target correspond to the lead, or Li{sub 17}Pb{sub 83}, cooled channels where the samples will be located. The available volumes there were shown enough for material testing purposes. Here, proposal of using those experimental areas to introduce small masses of radioactive wastes for testing of transmutation in spallation source is made. In addition, extrapolation of present conceptual design to make available larger volumes under flexible conditions seems to be possible. Neutrons leaking from the test zone drive a subcritical booster (<10 MW) which could provide a thermal neutron flux trap with a liquid hydrogen moderator in the center.

  14. Design and Fabrication of Titanium Target for Portable Neutron Generator

    International Nuclear Information System (INIS)

    Lee, Cheol Ho; Oh, Byunghoon; Chang, Daesik; Jang, Dohyun; In Sang Yeol; Park, Jaewon; Hong, Kwangpyo

    2014-01-01

    For the neutron generator to produce a neutron flux of the above order, a target that produces fast neutrons in the generator plays an important role, and the target is used and applied to develop the generator due to its simplicity and inexpensive. Making suitable targets for neutron production, especially mono-energy neutrons, has always been of interest. These targets have been used for neutron production reaction studies, calibration of detectors, and neutron therapy. Different studies have been carried out on deuterium and tritium for making solid targets to produce mono-energy neutron from D-D and D-T reactions. A lot of investigations have been carried out on solid target properties such as lifetime, thermal stability, neutron yield, and energy. Vaporized zirconium and titanium layers on a high thermal conductivity substrate (Cu, Mo, Ag) have been used as deuterium and tritium absorbing metals. The density of titanium is smaller than zirconium and the range of charged particles in the titanium targets is more than that in zirconium targets. Thus, titanium targets have more neutron yield than zirconium targets in a low energy beam and titanium is usually used to make a target. The titanium target was designed and simulated to determine the suitable thickness of the target. As a result of the simulation, the target was fabricated to generate fast neutrons by the reaction. The thickness of the target was measured using a profiler. The thickness of the two targets is 2.108 and 2.190 μm. The target will be applied to produce neutrons in a neutron generator

  15. Accelerator and neutron targets: a survey

    International Nuclear Information System (INIS)

    Kobisk, E.H.

    1974-01-01

    Although advances in electronics, ion source physics, detector technology, and other technical aspects of accelerator science have resulted in the capability of making highly sophisticated and accurate measurements of nuclear and atomic properties, the significance of such measurements is frequently dictated by the form, composition, and other characteristics of the target containing the nuclear species being studied. Consideration must be given to the impurity content, number of isotope nuclei per unit area, uniformity of nuclei distribution in the target, physical strength of the target, and myriad other factors. Most target characteristics are related to the mode(s) of preparation and to the quality of isotopic material used. A wide variety of target types and associated preparative methods are described and evaluated, together with methods of target characterization

  16. A target-moderator-reflector concept of the JAERI 5 MW pulsed spallation neutron source

    International Nuclear Information System (INIS)

    Watanabe, Noboru; Teshigawara, Makoto; Aizawa, Kazuya; Suzuki, Jyunichi; Oyama, Yukio

    1998-03-01

    In Japan Atomic Energy Research Institute the construction of a 5 MW (short) pulsed spallation neutron source is under planning using a projected high power superconducting proton (or H - ) linac of 8 MW in total beam power. In the present paper we report our consideration on target-moderator-reflector concept, based on the layout of the tentative neutron instruments for the assumed neutron scattering experiments in future. The choice of cold neutron moderators for high resolution and high intensity experiments, thermal and epithermal neutron moderators for high resolution uses was discussed and a reference layout of target-moderator-reflector system was proposed for detailed neutronic calculation and optimization. The proposed system was designed like that it can provide, at least, 30 beam lines for more than 40 instruments. (author)

  17. Spallation neutron source target station design, development, and commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Haines, J.R., E-mail: hainesjr@ornl.gov; McManamy, T.J.; Gabriel, T.A.; Battle, R.E.; Chipley, K.K.; Crabtree, J.A.; Jacobs, L.L.; Lousteau, D.C.; Rennich, M.J.; Riemer, B.W.

    2014-11-11

    The spallation neutron source target station is designed to safely, reliably, and efficiently convert a 1 GeV beam of protons to a high flux of about 1 meV neutrons that are available at 24 neutron scattering instrument beam lines. Research and development findings, design requirements, design description, initial checkout testing, and results from early operation with beam are discussed for each of the primary target subsystems, including the mercury target, neutron moderators and reflector, surrounding vessels and shielding, utilities, remote handling equipment, and instrumentation and controls. Future plans for the mercury target development program are also briefly discussed.

  18. Target injection and engagement for neutron generation at 1 Hz

    International Nuclear Information System (INIS)

    Komeda, Osamu; Mori, Yoshitaka; Nishimura, Yasuhiko

    2013-01-01

    Target injection is a key technology to realizing inertial fusion energy. Here we present the first demonstration of target injection and neutron generation. We injected more than 600 spherical deuterated polystyrene (C 8 D 8 ) bead targets during 10 minutes at 1 Hz. After the targets fell for a distance of 18 cm, we applied the synchronized laser-diode-pumped ultra-intense laser HAMA and successfully generated neutrons repeatedly. The result is a step toward fusion power and also suggests possible industrial neutron sources. (author)

  19. Integral measurements of neutron production in spallation targets

    International Nuclear Information System (INIS)

    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.; Greene, G.; Hanson, A.; Snead, L.; Thompson, R.; Ward, T.

    1998-01-01

    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)

  20. The neutronic performance of solid-target alternatives for SINQ

    International Nuclear Information System (INIS)

    Atchison, F.

    1991-01-01

    The results from calculations of the neutronic performance of three possible 'solid' targets and that of the current version of the liquid Pb-Bi target are presented. Two are 'conventional' transverse cooled plate structures, one using tantalum, the other tungsten. The third is a Pb-shot based pebble-bed design. Some general results on the effect of neutron absorption on the performance of the Pebble-bed target are given. (author)

  1. Spallation neutron production on thick target at saturne

    International Nuclear Information System (INIS)

    David, J.C.; David, J.C.; Varignon, C.; Borne, F.; Boudard, A.; Brochard, F.; Crespin, S.; Duchazeaubeneix, J.C.; Durand, D.; Durand, J.M.; Frehaut, J.; Hannappe, F.; Lebrun, C.; Lecolley, J.F.; Ledoux, X.; Lefebvres, F.; Legrain, R.; Leray, S.; Louvel, M.; Martinez, E.; Menard, S.; Milleret, G.; Patin, Y.; Petitbon, E.; Plouin, F.; Schapira, J.P.; Stugge, L.; Terrien, Y.; Thun, J.; Volant, C.; Whittal, D.M.

    2003-01-01

    In view of the new spallation neutron source projects, we discuss the characteristics of the neutron spectra on thick targets measured at SATURNE. Some comparisons to spallation models, and especially INCL4/ABLA implemented in the LAHET code, are done. (orig.)

  2. Target spot localization at neutron producing accelerators

    International Nuclear Information System (INIS)

    Medveczki, L.; Bornemisza-Pauspertl, P.

    1980-01-01

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

  3. Neutron transport from targets to moderators

    International Nuclear Information System (INIS)

    Taylor, A.D.

    1981-06-01

    By appropriately choosing parameters such as temperature, decoupler, thickness and effective size it is possible to tailor the moderators of a pulsed spallation neutron source in such a way that the different characteristics regarding time structure and spectral distribution as requested for the different instruments can be met very closely. This enables a unique flexibility in the design of neutron spectrometers to be used at such a source. (author)

  4. Development of lithium target for accelerator based neutron capture therapy

    International Nuclear Information System (INIS)

    Taskaev, Sergey; Bayanov, Boris; Belov, Victor; Zhoorov, Eugene

    2006-01-01

    Pilot innovative accelerator based neutron source for neutron capture therapy of cancer is now of the threshold of its operation at the BINP, Russia. One of the main elements of the facility is lithium target producing neutrons via threshold 7 Li(p,n) 7 Be reaction at 25 kW proton beam with energies 1.915 MeV or 2.5 MeV. The main problems of lithium target were determined to be: 7 Be radioactive isotope activation keeping lithium layer solid, presence of photons due to proton inelastic scattering on lithium nuclei, and radiation blistering. The results of thermal test of target prototype were presented as previous NCT Congress. It becomes clear that water is preferable for cooling the target, and that lithium target 10 cm in diameter is able to run before melting. In the present report, the conception of optimal target is proposed: thin metal disk 10 cm in diameter easy for detaching, with evaporated thin layer of pure lithium from the side of proton beam exposure, its back being intensively cooled with turbulent water flow to maintain lithium layer solid. Design of the target for the neutron source constructed at BINP is shown. The results of investigation of radiation blistering and lithium layer are presented. Target unit of facility is under construction now, and obtaining neutrons is expected in nearest future. (author)

  5. Beam splitting to improve target life in neutron generators

    International Nuclear Information System (INIS)

    Farrell, J.P.

    1976-01-01

    In a neutron generator in which a tritium-titanium target is bombarded by a deuterium ion beam, the target half-life is increased by separating the beam with a weak magnetic field to provide three separate beams of atomic, diatomic, and triatomic deuterium ions which all strike the target at different adjacent locations. Beam separation in this manner eliminates the problem of one type ion impairing the neutron generating efficiency of other type ions, thereby effecting more efficient utilization of the target material

  6. Fast neutron dose equivalent rates in heavy ion target areas

    International Nuclear Information System (INIS)

    Fulmer, C.B.; Butler, H.M.; Ohnesorge, W.F.; Mosko, S.W.

    1978-01-01

    At heavy ion accelerators, personnel access to areas near the target is sometimes important for successful performance of experiments. Radiation levels determine the amount of time that can be spent in these areas without exceeding maximum permissible exposures. Inasmuch as the fast neutrons contribute the major part of the Rem dose rates in these areas, knowledge of the fast neutron levels is important for planning permissive entry to target areas. Fast neutron dose rates were measured near thick medium mass targets bombarded with beams of C, N, O, and Ne ions. beam energies ranged from 3 to 16 MeV/amu. Dose rates (mrem/h) 1 meter from the target 90 degrees from the beam direction range from approx. 0.05 at MeV/amu to approx. 50 at 16 MeV/amu. These data should be helpful in planning permissive entry to heavy ion target areas

  7. Fast neutron dose equivalent rates in heavy ion target areas

    Energy Technology Data Exchange (ETDEWEB)

    Fulmer, C.B.; Butler, H.M.; Ohnesorge, W.F.; Mosko, S.W.

    1978-01-01

    At heavy ion accelerators, personnel access to areas near the target is sometimes important for successful performance of experiments. Radiation levels determine the amount of time that can be spent in these areas without exceeding maximum permissible exposures. Inasmuch as the fast neutrons contribute the major part of the Rem dose rates in these areas, knowledge of the fast neutron levels is important for planning permissive entry to target areas. Fast neutron dose rates were measured near thick medium mass targets bombarded with beams of C, N, O, and Ne ions. beam energies ranged from 3 to 16 MeV/amu. Dose rates (mrem/h) 1 meter from the target 90 degrees from the beam direction range from approx. 0.05 at MeV/amu to approx. 50 at 16 MeV/amu. These data should be helpful in planning permissive entry to heavy ion target areas.

  8. Constraining neutron guide optimizations with phase-space considerations

    Energy Technology Data Exchange (ETDEWEB)

    Bertelsen, Mads, E-mail: mads.bertelsen@gmail.com; Lefmann, Kim

    2016-09-11

    We introduce a method named the Minimalist Principle that serves to reduce the parameter space for neutron guide optimization when the required beam divergence is limited. The reduced parameter space will restrict the optimization to guides with a minimal neutron intake that are still theoretically able to deliver the maximal possible performance. The geometrical constraints are derived using phase-space propagation from moderator to guide and from guide to sample, while assuming that the optimized guides will achieve perfect transport of the limited neutron intake. Guide systems optimized using these constraints are shown to provide performance close to guides optimized without any constraints, however the divergence received at the sample is limited to the desired interval, even when the neutron transport is not limited by the supermirrors used in the guide. As the constraints strongly limit the parameter space for the optimizer, two control parameters are introduced that can be used to adjust the selected subspace, effectively balancing between maximizing neutron transport and avoiding background from unnecessary neutrons. One parameter is needed to describe the expected focusing abilities of the guide to be optimized, going from perfectly focusing to no correlation between position and velocity. The second parameter controls neutron intake into the guide, so that one can select exactly how aggressively the background should be limited. We show examples of guides optimized using these constraints which demonstrates the higher signal to noise than conventional optimizations. Furthermore the parameter controlling neutron intake is explored which shows that the simulated optimal neutron intake is close to the analytically predicted, when assuming that the guide is dominated by multiple scattering events.

  9. 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.

  10. Neutron penumbral imaging of laser-fusion targets

    International Nuclear Information System (INIS)

    Lerche, R.A.; Ress, D.B.

    1988-01-01

    Using a new technique, penumbral coded-aperture imaging, the first neutron images of laser-driven, inertial-confinement fusion targets were obtained. With these images the deuterium-tritium burn region within a compressed target can be measured directly. 4 references, 11 figures

  11. Neutron targets of Moscow meson facility status, problems, prospects

    Energy Technology Data Exchange (ETDEWEB)

    Sidorkin, S.; Koptelov, E.; Perekrestenko, A.; Stavissky, Y.; Trushkin, V.; Sobolevsky, N. [Institute for Nuclear Research RAS, 60-th October Anniversary Prospect, Moscow (Russian Federation)

    2001-03-01

    The status, problems and possible perspectives of target complexes of the Moscow meson factory is described in the report. The results of test proton beam session to neutron source are analysed. Some technical features of targets and expected modes in the nearest sessions are stated. (author)

  12. Clinical considerations for neutron capture therapy of brain tumors

    International Nuclear Information System (INIS)

    Madoc-Jones, H.; Wazer, D.E.; Zamenhof, R.G.; Harling, O.K.; Bernard, J.A. Jr.

    1990-01-01

    The radiotherapeutic management of primary brain tumors and metastatic melanoma in brain has had disappointing clinical results for many years. Although neutron capture therapy was tried in the US in the 1950s and 1960s, the results were not as hoped. However, with the newly developed capability to measure boron concentrations in blood and tissue both quickly and accurately, and with the advent of epithermal neutron beams obviating the need for scalp and skull reflection, it should not be possible to mount such a clinical trial of NCT again and avoid serious complications. As a prerequisite, it will be important to demonstrate the differential uptake of boron compound in brain tumor as compared with normal brain and its blood supply. If this can be done, then a trial of boron neutron capture therapy for brain tumors should be feasible. Because boronated phenylalanine has been demonstrated to be preferentially taken up by melanoma cells through the biosynthetic pathway for melanin, there is special interest in a trial of boron neutron capture therapy for metastatic melanoma in brain. Again, the use of an epithermal beam would make this a practical possibility. However, because any epithermal (or thermal) beam must contain a certain contaminating level of gamma rays, and because even a pure neutron beam cases gamma rays to be generated when it interacts with tissue, they think that it is essential to deliver treatments with an epithermal beam for boron neutron capture therapy in fractions in order to minimize the late-effects of low-LET gamma rays in the normal tissue

  13. Neutronics for the SNS long wavelength target station

    International Nuclear Information System (INIS)

    Iverson, E.B.; Micklich, B.J.; Carpenter, J.M.

    2001-01-01

    One of the most significant and adventurous aspects of the LWTS (Long Wavelength Target Station) design concept is the use of slab moderators, historically considered to be awkward due to the high contamination of the neutron beams with fast and high- energy neutrons. Concern over this contamination is the reason behind our proposition that none of the beam on a slab moderator should be viewed directly, that is, without a curved guide, compact bender, or other fast and high-energy neutron filter. We made a large number of calculations concerning fast neutron source term of the solid target-slab moderator configuration with monolithic solid methane, which includes a curved guide or compact beam bender. We also made optimization on target position, beam void open angle, target gap and target division of the split target configuration. All fast and high-energy neutron spectra will be reported as lethargy spectra, normalized to 1 eV. In this way, we will attempt to define the 'cost' of using slab moderators as a function of the payoff gained from their use. We report these data for general information and discussion, and further draw the conclusions. Numerous issues have arisen in the course of the LWTS concept development, which require more information than is now in hand to provide the basis for detailed design and for potential design innovations. Some of the R and D issues are listed, along with proposed efforts to fill design needs. We have devised a highly effective 'base case' conceptual design for LWTS, which we are still evaluating and optimizing. LWTS will provide distinctly unique capabilities complimentary to SNS (Spallation Neutron Source) HPTS (High Power Target Station). The configuration of LWTS is strongly coupled to instrument requirements through close interaction with scientists formulating the science case and instrument suite. (Tanaka, Y.)

  14. Design of a cryogenic deuterium gas target for neutron therapy

    International Nuclear Information System (INIS)

    Kuchnir, F.T.; Waterman, F.M.; Forsthoff, H.; Skaggs, L.S.; Vander Arend, P.C.; Stoy, S.

    1976-01-01

    A cryogenic deuterium gas target operating at 80 0 K and 10 atm pressure has been designed for use with a small cyclotron; the D(d,n) reaction is used to produce a neutron beam suitable for radiation therapy. The target is cooled by circulation of the gas in a closed loop between the target and an external heat exchanger immersed in liquid nitrogen

  15. 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.

  16. Neutronics and radiation field studies for the RIA fragmentation target area

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, Susana [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States)]. E-mail: reyes20@llnl.gov; Boles, Jason L. [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States); Ahle, Larry E. [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States); Stein, Werner [Lawrence Livermore National Laboratory, P.O. Box 808, L-446, Livermore, CA 94550 (United States)

    2006-06-23

    Neutronics simulations and activation evaluations are currently in progress as part of the pre-conceptual research and development effort for the Rare Isotope Accelerator (RIA). The RIA project involves generating heavy element ion beams with powers up to 400 kw for use in a fragmentation target line to produce selected ion beams for physics research experiments. Designing a fragmentation beam dump for RIA is one of the most critical challenges for such a facility. Here, we present the results from neutronics and radiation field assessments for various beam dump concepts that can meet requirements for the RIA fragmentation line. Preliminary results from heavy ion transport including radiation damage evaluations for the RIA fragmentation beam dump are also presented. Initial neutronics and activation studies will be incorporated with other target area considerations to identify important challenges and explore possible solutions.

  17. Neutronics and radiation field studies for the RIA fragmentation target area

    Science.gov (United States)

    Reyes, Susana; Boles, Jason L.; Ahle, Larry E.; Stein, Werner

    2006-06-01

    Neutronics simulations and activation evaluations are currently in progress as part of the pre-conceptual research and development effort for the Rare Isotope Accelerator (RIA). The RIA project involves generating heavy element ion beams with powers up to 400 kW for use in a fragmentation target line to produce selected ion beams for physics research experiments. Designing a fragmentation beam dump for RIA is one of the most critical challenges for such a facility. Here, we present the results from neutronics and radiation field assessments for various beam dump concepts that can meet requirements for the RIA fragmentation line. Preliminary results from heavy ion transport including radiation damage evaluations for the RIA fragmentation beam dump are also presented. Initial neutronics and activation studies will be incorporated with other target area considerations to identify important challenges and explore possible solutions.

  18. LANSCE (Los Alamos Neutron Scattering Center) target system performance

    International Nuclear Information System (INIS)

    Russell, G.J.; Gilmore, J.S.; Robinson, H.; Legate, G.L.; Bridge, A.; Sanchez, R.J.; Brewton, R.J.; Woods, R.; Hughes, H.G. III

    1989-01-01

    The authors measured neutron beam fluxes at LANSCE using gold foil activation techniques. They did an extensive computer simulation of the as-built LANSCE Target/Moderator/Reflector/Shield geometry. They used this mockup in a Monte Carlo calculation to predict LANSCE neutronic performance for comparison with measured results. For neutron beam fluxes at 1 eV, the ratio of measured data to calculated varies from ∼0.6-0.9. The computed 1 eV neutron leakage at the moderator surface is 3.9 x 10 10 n/eV-sr-s-μA for LANSCE high-intensity water moderators. The corresponding values for the LANSCE high-resolution water moderator and the liquid hydrogen moderator are 3.3 and 2.9 x 10 10 , respectively. LANSCE predicted moderator intensities (per proton) for a tungsten target are essentially the same as ISIS predicted moderator intensities for a depleted uranium target. The calculated LANSCE steady state unperturbed thermal (E 13 n/cm 2 -s. The unique LANSCE split-target/flux-trap-moderator system is performing exceedingly well. The system has operated without a target or moderator change for over three years at nominal proton currents of 25 μA of 800-MeV protons. 17 refs., 8 figs., 3 tabs

  19. Computational Dosimetry and Treatment Planning Considerations for Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Nigg, David Waler

    2003-01-01

    Specialized treatment planning software systems are generally required for neutron capture therapy (NCT) research and clinical applications. The standard simplifying approximations that work well for treatment planning computations in the case of many other modalities are usually not appropriate for application to neutron transport. One generally must obtain an explicit three-dimensional numerical solution of the governing transport equation, with energy-dependent neutron scattering completely taken into account. Treatment planning systems that have been successfully introduced for NCT applications over the past 15 years rely on the Monte Carlo stochastic simulation method for the necessary computations, primarily because of the geometric complexity of human anatomy. However, historically, there has also been interest in the application of deterministic methods, and there have been some practical developments in this area. Most recently, interest has turned toward the creation of treatment planning software that is not limited to any specific therapy modality, with NCT as only one of several applications. A key issue with NCT treatment planning has to do with boron quantification, and whether improved information concerning the spatial biodistribution of boron can be effectively used to improve the treatment planning process. Validation and benchmarking of computations for NCT are also of current developmental interest. Various institutions have their own procedures, but standard validation models are not yet in wide use

  20. Calculation of Spectra of Neutrons and Charged Particles Produced in a Target of a Neutron Generator

    Science.gov (United States)

    Gaganov, V. V.

    2017-12-01

    An algorithm for calculating the spectra of neutrons and associated charged particles produced in the target of a neutron generator is detailed. The products of four nuclear reactions 3H( d, n)4He, 2H( d, n)3He, 2H( d, p)3H, and 3He( d, p)4He are analyzed. The results of calculations are presented in the form of neutron spectra for several emission angles and spectra of associated charged particles emitted at an angle of 180° for a deuteron initial energy of 0.13 MeV.

  1. Absolute measurement of the subcriticality based on the third order neutron correlation in consideration of the finite nature of neutron counts data

    International Nuclear Information System (INIS)

    Endo, Tomohiro; Kitamura, Yasunori; Yamane, Yoshihiro

    2003-01-01

    We have studied a measurement of subcriticality by using the neutron correlation method. Furuhashi proposed an absolute measurement of subcriticality by using the third order neutron correlation factor X in addition to the second order neutron correlation factor Y. In actual experiments, the number of neutron counts data is not infinity so that we take the effect of the finite nature of the neutron counts data into account. We derived new formulas in consideration of the number of data and verified them. (author)

  2. Optimum design of exploding pusher target to produce maximum neutrons

    International Nuclear Information System (INIS)

    Kitagawa, Y.; Miyanaga, N.; Kato, Y.; Nakatsuka, M.; Nishiguchi, A.; Yabe, T.; Yamanaka, C.

    1985-03-01

    Exploding pusher target experiments have been conducted with the 1.052-μm GEKKO MII two-beam glass laser system to design an optimum target, which couples to the incident laser light most effectively to produce the maximum neutrons. Since hot electrons preheat the shell entirely in spite of strongly nonuniform irradiation, a simple model can design the optimum target, of which the shell/fuel interface is accelerated to 0.5 to 0.7 times the initial radius within a laser pulse. A 2-dimensional computer simulation supports this target design. The scaling of the neutron yield N with the laser power P is N ∝ P 2.4±0.4 . (author)

  3. Analytic model of heat deposition in spallation neutron target

    International Nuclear Information System (INIS)

    Findlay, D.J.S.

    2015-01-01

    A simple analytic model for estimating deposition of heat in a spallation neutron target is presented—a model that can readily be realised in an unambitious spreadsheet. The model is based on simple representations of the principal underlying physical processes, and is intended largely as a ‘sanity check’ on results from Monte Carlo codes such as FLUKA or MCNPX.

  4. Analytic model of heat deposition in spallation neutron target

    Energy Technology Data Exchange (ETDEWEB)

    Findlay, D.J.S.

    2015-12-11

    A simple analytic model for estimating deposition of heat in a spallation neutron target is presented—a model that can readily be realised in an unambitious spreadsheet. The model is based on simple representations of the principal underlying physical processes, and is intended largely as a ‘sanity check’ on results from Monte Carlo codes such as FLUKA or MCNPX.

  5. A new, 13C-based material for neutron targets

    International Nuclear Information System (INIS)

    Romanenko, A.I.; Anikeeva, O.B.; Gorbachev, R.V.; Zhmurikov, E.I.; Gubin, K.V.; Logachev, P.V.; Avilov, M.S.; Tsybulya, S.V.; Kryukova, G.N.; Burgina, E.B.; Tecchio, L.

    2005-01-01

    A 13 C-based neutron-target material is investigated using X-ray diffraction, IR absorption and Raman scattering spectroscopies, transmission electron microscopy, and electrical (conductivity, magnetoresistance, and Hall effect) measurements before and after high-power electron irradiation for various lengths of time [ru

  6. CONSIDERATIONS ABOUT PROTON - NEUTRON INTERACTIONS IN THE INTERSECTING STORAGE RINGS

    CERN Document Server

    Bartl, W; Steuer, M; Hubner, K

    1969-01-01

    The pos'sibility of proton-neutron scattering experiments at the CERN Intersecting Storage Rings is studied. The use of proton-deuteron collisions to measure the reaction p+d •*• p*pv+n,witheitherp.orn,asspectator nucléon is discussed. An analysing magnet around the deuteron beamline allows to detect both nucléons of the deuteron up to the zero-momentum-transfer" région. Accélération and storage of deuteron beams is considered.

  7. Beryllium armoured target for extreme heat and neutron loading conditions

    International Nuclear Information System (INIS)

    Mazul, I.; Gervash, A.; Giniyatulin, R.

    2004-01-01

    Beryllium is a primary candidate as a target material for high-energy protons conversion into neutrons used for different applications. In order to get higher neutron flux the conversion area has to be minimized - in our case the target is limited by 1-2 liter volume. This target generates about 5·10 13 fast neutrons per second and removes of 150 kW thermal power deposited by proton beam (30 mA, 5 MeV), coming from linac. The operational condition of the converter is close to the condition of Be-armored components in fusion reactors: high thermal and neutron fluxes and active cooling. Therefore achievements in development of water-cooled high heat flux components for fusion application can be used for design of Be converter and vice versa. However for medical application the using of high-activated heat sink materials such as Cu and SS is strongly limited. So, new materials (Be, Al, Zr) and new joining technologies in comparison with the achievements in fusion area have to be used for construction of such Be converter. In order to reduce amount of heat sink materials in the target saddle-block geometry for Be armor is suggested and developed. Results of R and D works on the development of water cooled Be target for converter are presented, including data on selected materials, technological trials and mockups high heat flux testing. Preliminary design of Be neutron converter for medical applications based on R and D results is presented. (author)

  8. Design considerations for neutron activation and neutron source strength monitors for ITER

    International Nuclear Information System (INIS)

    Barnes, C.W.; Jassby, D.L.; LeMunyan, G.; Roquemore, A.L.

    1997-01-01

    The International Thermonuclear Experimental Reactor will require highly accurate measurements of fusion power production in time, space, and energy. Spectrometers in the neutron camera could do it all, but experience has taught us that multiple methods with redundancy and complementary uncertainties are needed. Previously, conceptual designs have been presented for time-integrated neutron activation and time-dependent neutron source strength monitors, both of which will be important parts of the integrated suite of neutron diagnostics for this purpose. The primary goals of the neutron activation system are: to maintain a robust relative measure of fusion energy production with stability and wide dynamic range; to enable an accurate absolute calibration of fusion power using neutronic techniques as successfully demonstrated on JET and TFTR; and to provide a flexible system for materials testing. The greatest difficulty is that the irradiation locations need to be close to plasma with a wide field of view. The routing of the pneumatic system is difficult because of minimum radius of curvature requirements and because of the careful need for containment of the tritium and activated air. The neutron source strength system needs to provide real-time source strength vs. time with ∼1 ms resolution and wide dynamic range in a robust and reliable manner with the capability to be absolutely calibrated by in-situ neutron sources as done on TFTR, JT-60U, and JET. In this paper a more detailed look at the expected neutron flux field around ITER is folded into a more complete design of the fission chamber system

  9. Long-Lifetime Low-Scatter Neutron Polarization Target

    International Nuclear Information System (INIS)

    Richardson, Jonathan M.

    2004-01-01

    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

  10. Some target assay uncertainties for passive neutron coincidence counting

    International Nuclear Information System (INIS)

    Ensslin, N.; Langner, D.G.; Menlove, H.O.; Miller, M.C.; Russo, P.A.

    1990-01-01

    This paper provides some target assay uncertainties for passive neutron coincidence counting of plutonium metal, oxide, mixed oxide, and scrap and waste. The target values are based in part on past user experience and in part on the estimated results from new coincidence counting techniques that are under development. The paper summarizes assay error sources and the new coincidence techniques, and recommends the technique that is likely to yield the lowest assay uncertainty for a given material type. These target assay uncertainties are intended to be useful for NDA instrument selection and assay variance propagation studies for both new and existing facilities. 14 refs., 3 tabs

  11. RTNS-II [Rotating Target Neutron Source II] operational summary

    International Nuclear Information System (INIS)

    Heikkinen, D.W.

    1988-09-01

    The Rotating Target Neutron Source II facility (RTNS-II) operated for over nine years. Its purpose was to provide high intensities of 14 MeV neutrons for materials studies in the fusion energy program. For the period from 1982-1987, the facility was supported by both the US (Department of Energy) and Japan (Ministry of Education, Culture, and Science). RTNS-II contains two accelerator-based neutron sources which use the T(d,n) 4 He reaction. In this paper, we will summarize the operational history of RTNS-II. Typical operating parameters are given. In addition, a brief description of the experimental program is presented. The current status and future options for the facility are discussed. 7 refs., 5 tabs

  12. Spallation neutron source target design for radioactive waste transmutation

    International Nuclear Information System (INIS)

    Beard, C.A.

    1992-01-01

    The disposal of high-level radioactive waste has long been one of the most serious problems facing the nuclear industry. Transmutation of this waste through particle bombardment has been suggested numerous times as a possible method of enhancing the waste management process. Due to advances in accelerator technology, the feasibility of an accelerator based transmutation system has increased enough to allow serious investigation of this process. Therefore, in pursuit of this goal, an accelerator target was designed for use in an accelerator based transmutation system. The target design consists of an array of tantalum rods, cooled by liquid sodium, which are arranged in a cylindrical configuration 40 cm in diameter and 125 cm in height. Tantalum was chosen as the target material over tungsten, lead, bismuth, and a lead-bismuth alloy (55 w/o bismuth) due to a large neutron yield, low activation, low chemical toxicity, and the fact that it does not produce significant amounts of long-lived isotopes through spallation or activation. The target yields a neutron source of 29.7 neutrons/proton when exposed to a 1600 MeV proton beam, and is suitable for use with both thermal or fast spectrum transmutation systems

  13. Some preliminary design considerations for the ANS [Advanced Neutron Source] reactor cold source

    International Nuclear Information System (INIS)

    Henderson, D.L.

    1988-01-01

    Two areas concerned with the design of the Advanced Neutron Source (ANS) cold source have been investigated by simple one-dimensional calculations. The gain factors computed for a possible liquid nitrogen-15 cold source moderator are considerably below those computed for the much colder liquid deuterium moderator, as is reasonable considering the difference in moderator temperature. Nevertheless, nitrogen-15 does represent a viable option should safety related issues prohibit the use of deuterium as a moderating material. The slab geometry calculations have indicated that reflection of neutrons may be the dominant moderating mechanism and should be a consideration in the design of the cold source. 9 refs., 2 figs

  14. Targets for the production of neutron activated molybdenum-99

    International Nuclear Information System (INIS)

    Hetherington, E.L.R.; Boyd, R.E.

    1999-01-01

    Neutron activation of natural molybdenum is, ostensibly, the least complex route to 99m Tc. However in most commercial generators the severe limitation in 99 Mo specific activity that the route imposes has caused manufacturers to choose the alternative fission process despite its disadvantages of being more expensive and requiring a more complex waste management strategy. The development of a newer generator technology is capable of reviving the demand for neutron activated 99 Mo and might encourage the production of 99m Tc by countries possessing less developed nuclear infrastructures. The targets used in the (n,γ) production route consist of analytical grade molybdenum trioxide which has been further refined to remove both rhenium and tungsten trace impurities. The basic methods used by ANSTO to produce a molybdenum target capable of yielding 99m Tc of high radionuclidic purity are described. (author)

  15. LANL sunnyside experiment: Study of neutron production in accelerator-driven targets

    International Nuclear Information System (INIS)

    Morgan, G.; Butler, G.; Cappiello, M.; Carius, S.; Daemen, L.; DeVolder, B.; Frehaut, J.; Goulding, C.; Grace, R.; Green, R.; Lisowski, P.; Littleton, P.; King, J.; King, N.; Prael, R.; Stratton, T.; Turner, S.; Ullmann, J.; Venneri, F.; Yates, M.

    1995-01-01

    Measurements have been made of the neutron production in prototypic targets for accelerator driven systems. Studies were conducted on four target assemblies containing lead, lithium, tungsten, and a thorium-salt mixture. Integral data on total neutron production were obtained as well as more differential data on neutron leakage and neutron flux profiles in the blanket/moderator region. Data analysis on total neutron production is complete and shows excellent agreement with calculations using the LAHET/MCNP code system

  16. LANL sunnyside experiment: Study of neutron production in accelerator-driven targets

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, G.; Butler, G.; Cappiello, M. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-10-01

    Measurements have been made of the neutron production in prototypic targets for accelerator driven systems. Studies were conducted on four target assemblies containing lead, lithium, tungsten, and a thorium-salt mixture. Integral data on total neutron production were obtained as well as more differential data on neutron leakage and neutron flux profiles in the blanket/moderator region. Data analysis on total neutron production is complete and shows excellent agreement with calculations using the LAHET/MCNP code system.

  17. Design considerations for primary neutron beam collimation on the Spallation Neutron Source

    International Nuclear Information System (INIS)

    Howells, W.S.

    1980-09-01

    A scheme for the design of primary neutron beam collimation is presented which is based on ray diagrams. The practical application of the ideas is outlined and the influence of various constraints such as beam shutters is discussed. The ideas are illustrated with examples which include the layouts for some typical instruments. (author)

  18. Laser driven compression and neutron generation with spherical shell targets

    International Nuclear Information System (INIS)

    Campbell, P.M.; Hammerling, P.; Johnson, R.R.; Kubis, J.J.; Mayer, F.J.

    1977-01-01

    Laser-driven implosion experiments using DT-gas-filled spherical glass-shell targets are described. Neutron yields to 5 x 10 7 are produced from implosions of small ( -- 55 μm-diameter) targets spherically illuminated with an on-target laser power of 0.4 terawatt. Nuclear reaction product diagnostics, X-ray pinhole photographs, fast-ion spectra and X-ray measurements are used in conjunction with hydrodynamic computer code simulations to investigate the implosion phenomenology as well as the target corona evolution. Simulations using completely classical effects are not able to describe the full range of experimental data. Electron or radiation preheating may be required to explain some implosion measurements. (auth.)

  19. Low energy neutron scattering for energy dependent cross sections. General considerations

    Energy Technology Data Exchange (ETDEWEB)

    Rothenstein, W; Dagan, R [Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Mechanical Engineering

    1996-12-01

    We consider in this paper some aspects related to neutron scattering at low energies by nuclei which are subject to thermal agitation. The scattering is determined by a temperature dependent joint scattering kernel, or the corresponding joint probability density, which is a function of two variables, the neutron energy after scattering, and the cosine of the angle of scattering, for a specified energy and direction of motion of the neutron, before the interaction takes place. This joint probability density is easy to calculate, when the nucleus which causes the scattering of the neutron is at rest. It can be expressed by a delta function, since there is a one to one correspondence between the neutron energy change, and the cosine of the scattering angle. If the thermal motion of the target nucleus is taken into account, the calculation is rather more complicated. The delta function relation between the cosine of the angle of scattering and the neutron energy change is now averaged over the spectrum of velocities of the target nucleus, and becomes a joint kernel depending on both these variables. This function has a simple form, if the target nucleus behaves as an ideal gas, which has a scattering cross section independent of energy. An energy dependent scattering cross section complicates the treatment further. An analytic expression is no longer obtained for the ideal gas temperature dependent joint scattering kernel as a function of the neutron energy after the interaction and the cosine of the scattering angle. Instead the kernel is expressed by an inverse Fourier Transform of a complex integrand, which is averaged over the velocity spectrum of the target nucleus. (Abstract Truncated)

  20. Spallation Neutron Source Second Target Station Integrated Systems Update

    Energy Technology Data Exchange (ETDEWEB)

    Ankner, John Francis [ORNL; An, Ke [ORNL; Blokland, Willem [ORNL; Charlton, Timothy R. [ORNL; Coates, Leighton [ORNL; Dayton, Michael J. [ORNL; Dean, Robert A. [ORNL; Dominguez-Ontiveros, Elvis E. [ORNL; Ehlers, Georg [ORNL; Gallmeier, Franz X. [ORNL; Graves, Van B. [ORNL; Heller, William T. [ORNL; Holmes, Jeffrey A. [ORNL; Huq, Ashfia [ORNL; Lumsden, Mark D. [ORNL; McHargue, William M. [ORNL; McManamy, Thomas J. [ORNL; Plum, Michael A. [ORNL; Rajic, Slobodan [ORNL; Remec, Igor [ORNL; Robertson, Lee [ORNL; Sala, Gabriele [ORNL; Stoica, Alexandru Dan [ORNL; Trotter, Steven M. [ORNL; Winn, Barry L. [ORNL; Abudureyimu, Reheman [ORNL; Rennich, Mark J. [ORNL; Herwig, Kenneth W. [ORNL

    2017-04-01

    The Spallation Neutron Source (SNS) was designed from the beginning to accommodate both an accelerator upgrade to increase the proton power and a second target station (STS). Four workshops were organized in 2013 and 2014 to identify key science areas and challenges where neutrons will play a vital role [1-4]. Participants concluded that the addition of STS to the existing ORNL neutron sources was needed to complement the strengths of High Flux Isotope Reactor (HFIR) and the SNS first target station (FTS). To address the capability gaps identified in the workshops, a study was undertaken to identify instrument concepts that could provide the required new science capabilities. The study outlined 22 instrument concepts and presented an initial science case for STS [5]. These instrument concepts formed the basis of a planning suite of instruments whose requirements determined an initial site layout and moderator selection. An STS Technical Design Report (TDR) documented the STS concept based on those choices [6]. Since issue of the TDR, the STS concept has significantly matured as described in this document.

  1. Calculation of neutron spectra produced in neutron generator target: Code testing.

    Science.gov (United States)

    Gaganov, V V

    2018-03-01

    DT-neutron spectra calculated using the SRIANG code was benchmarked against the results obtained by widely used Monte Carlo codes: PROFIL, SHORIN, TARGET, ENEA-JSI, MCUNED, DDT and NEUSDESC. The comparison of the spectra obtained by different codes confirmed the correctness of SRIANG calculations. The cross-checking of the compared spectra revealed some systematic features and possible errors of analysed codes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The space distribution of neutrons generated in massive lead target by relativistic nuclear beam

    International Nuclear Information System (INIS)

    Chultem, D.; Damdinsuren, Ts.; Enkh-Gin, L.; Lomova, L.; Perelygin, V.; Tolstov, K.

    1993-01-01

    The present paper is devoted to implementation of solid state nuclear track detectors in the research of the neutron generation in extended lead spallation target. Measured neutrons space distribution inside the lead target and neutron distribution in the thick water moderator are assessed. (Author)

  3. 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.

  4. Calculating the energy spectrum of neutrons from tritium target of the NG-150 type generator

    International Nuclear Information System (INIS)

    Bortash, A.I.; Kuznetsov, V.S.

    1987-01-01

    Calculation procedure of neutron spectra yielding from the NG-150 generator target chamber with regard to deutron moderation is suggested. Using the suggested procedure, neutron spectra for different escape angles formed in the tritium target are calculated. The spectrum of neutrons scattered in cooling water is calculated. The mean energy of neutrons escaping at the angle of 0 deg equalling 14.5 MeV is obtained

  5. Spallation target-moderator-reflector studies at the Weapons Neutron Research facility

    International Nuclear Information System (INIS)

    Russell, G.J.; Gilmore, J.S.; Prael, S.D.; Robinson, H.; Howe, S.D.

    1980-01-01

    Basic neutronics data, initiated by 800-MeV proton spallation reactions, are important to spallation neutron source development and electronuclear fuel production. Angle-dependent and energy-dependent neutron production cross sections, energy-dependent and total neutron yields, thermal and epithermal neutron surface and beam fluxes, and fertile-to-fissile conversion ratios are being measured. The measurements are being done at the Weapons Neutron Research facility on a variety of targets and target-moderator-reflector configurations. The experiments are relevant to the above applications, and provide data to validate computer codes. Preliminary results are presented and compared to calculated predictions. 13 figures

  6. Neutron production in interactions of relativistic protons and deuterons with lead targets

    International Nuclear Information System (INIS)

    Yurevich, V.I.; Amelin, N.S.; Yakovlev, R.M.; Nikolaev, V.A.; Lyapin, V.G.; Tsvetkov, I.O.

    2005-01-01

    Results on the neutron double-differential cross sections and yields obtained in the time-of-flight measurements with different lead targets and beams of protons and deuterons at an energy of about 2 GeV are discussed. The neutron spatial-energy distribution for an extended lead target was studied by the threshold detector method in the energy range of protons and deuterons 1-3.7 GeV. A dependence of the mean neutron multiplicity, energy of neutrons, and process of neutron multiplication in lead on the target dimension, and the type and energy of the beam particle is analyzed. (author)

  7. Calculations of radiation damage in target, container and window materials for spallation neutron sources

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Mansur, L.K.

    1996-01-01

    Radiation damage in target, container, and window materials for spallation neutron sources is am important factor in the design of target stations for accelerator-driver transmutation technologies. Calculations are described that use the LAHET and SPECTER codes to obtain displacement and helium production rates in tungsten, 316 stainless steel, and Inconel 718, which are major target, container, and window materials, respectively. Results are compared for the three materials, based on neutron spectra for NSNS and ATW spallation neutron sources, where the neutron fluxes are normalized to give the same flux of neutrons of all energies

  8. Development of beryllium-based neutron target system with three-layer structure for accelerator-based neutron source for boron neutron capture therapy.

    Science.gov (United States)

    Kumada, Hiroaki; Kurihara, Toshikazu; Yoshioka, Masakazu; Kobayashi, Hitoshi; Matsumoto, Hiroshi; Sugano, Tomei; Sakurai, Hideyuki; Sakae, Takeji; Matsumura, Akira

    2015-12-01

    The iBNCT project team with University of Tsukuba is developing an accelerator-based neutron source. Regarding neutron target material, our project has applied beryllium. To deal with large heat load and blistering of the target system, we developed a three-layer structure for the target system that includes a blistering mitigation material between the beryllium used as the neutron generator and the copper heat sink. The three materials were bonded through diffusion bonding using a hot isostatic pressing method. Based on several verifications, our project chose palladium as the intermediate layer. A prototype of the neutron target system was produced. We will verify that sufficient neutrons for BNCT treatment are generated by the device in the near future. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Continuous energy Neutron Transport Monte Carlo Simulator Project: Decomposition of the neutron energy spectrum by target nuclei tagging

    Energy Technology Data Exchange (ETDEWEB)

    Barcellos, Luiz Felipe F.C.; Bodmann, Bardo E.J.; Vilhena, Marco T.M.B., E-mail: luizfelipe.fcb@gmail.com, E-mail: bardo.bodmann@ufrgs.br, E-mail: mtmbvilhena@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Grupo de Estudos Nucleares; Leite, Sergio Q. Bogado, E-mail: sbogado@ibest.com.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    In this work a Monte Carlo simulator with continuous energy is used. This simulator distinguishes itself by using the sum of three probability distributions to represent the neutron spectrum. Two distributions have known shape, but have varying population of neutrons in time, and these are the fission neutron spectrum (for high energy neutrons) and the Maxwell-Boltzmann distribution (for thermal neutrons). The third distribution has an a priori unknown and possibly variable shape with time and is determined from parametrizations of Monte Carlo simulation. It is common practice in neutron transport calculations, e.g. multi-group transport, to consider that the neutrons only lose energy with each scattering reaction and then to use a thermal group with a Maxwellian distribution. Such an approximation is valid due to the fact that for fast neutrons up-scattering occurrence is irrelevant, being only appreciable at low energies, i.e. in the thermal energy region, in which it can be regarded as a Maxwell-Boltzmann distribution for thermal equilibrium. In this work the possible neutron-matter interactions are simulated with exception of the up-scattering of neutrons. In order to preserve the thermal spectrum, neutrons are selected stochastically as being part of the thermal population and have an energy attributed to them taken from a Maxwellian distribution. It is then shown how this procedure can emulate the up-scattering effect by the increase in the neutron population kinetic energy. Since the simulator uses tags to identify the reactions it is possible not only to plot the distributions by neutron energy, but also by the type of interaction with matter and with the identification of the target nuclei involved in the process. This work contains some preliminary results obtained from a Monte Carlo simulator for neutron transport that is being developed at Federal University of Rio Grande do Sul. (author)

  10. Influence of target-scattered neutrons on cross-section measurements

    International Nuclear Information System (INIS)

    Lesiecki, H.; Cosack, M.; Siebert, B.R.L.

    1985-01-01

    Monoenergetic neutrons produced with accelerators are usually accompanied by degraded and secondary neutrons which arise from reactions of source neutrons in the material of the target construction. A Monte Carlo code was written which takes into account the kinematics and the angular source strength of the neutron producing reaction and the interactions of the neutrons with the material in the immediate vicinity of their production. The calculation of the spectral distribution of the neutron fluence is compared with the result of a time-of-flight measurement. (author)

  11. 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.

  12. Separation of heavier rare earths from neutron irradiated uranium targets

    International Nuclear Information System (INIS)

    Bhargava, V.K.; Rao, V.K.; Marathe, S.G.; Sahakundu, S.M.; Iyer, R.H.

    1978-01-01

    A radiochemical method is described for the separation of heavier rare earths from the fission of uranium. The method is particularly suitable for the separation of low yield (10sup(-5)%-10sup(-7)%), highly asymmetric rare earth fission products viz. sup(179,177)Lu, sup(175)Yb, sup(173)Tm, sup(172,171)Er, sup(167)Ho and sup(161,160)Tb in the neutron induced fission of natural and depleted uranium targets. Additional separation steps have been incorporated for decontamination from sup(239)Np (an activation product) and sup(93-90)Y (a high fission-yield product) which show similar chemical behaviour to rare earths. Separation of individual rare earths is achieved by a cation exchange method performed at 80 deg C by elution with α-hydroxyisobutyric acid (α-HIBA). (author)

  13. Consideration of impact behaviour of radioactive packages onto real targets

    International Nuclear Information System (INIS)

    Shirai, K.; Akamatsu, H.; Ito, C.; Ryu, H.

    1993-01-01

    In this study, distinct element method (DEM) was applied to simulate the dynamic fracture impact behaviours of the real targets, and drop tests and analyses onto various object surfaces were performed using 48Y-cylinder in order to clarify the relation between the object surface hardness and the associated impact response of the packages. Following the results of the drop tests and analysis, the outline of contents and results is summarized below. 1) Drop Tests were performed using 48Y-cylinder considering target object hardness in real drop accidents nad the effects of the target object hardness on the drop impact response was made clear experimentally. 2) DEM was applied to the drop analysis onto real targets and it is confirmed that the accuracy of the drop analysis onto real targets using DEM is good enough to estimate the impact load that occurred in the packages. 3) Based on the drop tests and analysis results onto various object surfaces, the relation between the target hardness and the impact response of 48Y-cylinder was made clear, and also the method to estimate the relationship between the drop height for real targets and the equivalent drop height onto the unyielding surface was proposed. (J.P.N.)

  14. Engineering nucleases for gene targeting: safety and regulatory considerations.

    Science.gov (United States)

    Pauwels, Katia; Podevin, Nancy; Breyer, Didier; Carroll, Dana; Herman, Philippe

    2014-01-25

    Nuclease-based gene targeting (NBGT) represents a significant breakthrough in targeted genome editing since it is applicable from single-celled protozoa to human, including several species of economic importance. Along with the fast progress in NBGT and the increasing availability of customized nucleases, more data are available about off-target effects associated with the use of this approach. We discuss how NBGT may offer a new perspective for genetic modification, we address some aspects crucial for a safety improvement of the corresponding techniques and we also briefly relate the use of NBGT applications and products to the regulatory oversight. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Heavy water jet target and a beryllium target for production of fast neutrons

    International Nuclear Information System (INIS)

    Logan, C.M.; Anderson, J.D.; Barschall, H.H.; Davis, J.C.

    1975-01-01

    A limitation on the neutron flux obtainable from proton or deuteron induced reactions is the heating of the target by the accelerated charged particles. The heat can be removed more easily if the target moves. The possibility of using a rotating Be target and a heavy water jet as a target for bombardment by 35-MeV deuterons was studied. In a thick Be metal target moving at 10 m/sec through such a beam of 1 cm diameter a temperature pulse of about 300 0 C will be produced by the 0.3 MW beam. The Be target should be able to withstand such a temperature pulse. A Be target suitable for 3 MW of power in a 1 cm diameter beam would require internal cooling and a higher velocity. A free jet of heavy water is also a possible target. Laser photographs of water jets in vacuum show small angles of divergence. The effect of heating by a 0.3 MW beam is probably not important because the temperature rise produced by the beam is small compared to the absolute temperature of the unheated jet. (auth)

  16. Analysis of the Neutron Generator and Target for the LSDTS System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Je; Lee, Yong Deok; Song, Jae Hoon; Song, Kee Chan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-11-15

    A preliminary analysis was performed based on the literatures and the patents for the neutron generators and targets for the lead slowing down time spectrometer (LSDTS) system. It was found that local neutron generator did not exhibit enough neutron intensity such as 1E+12 n/s, which is a minimum requirement for the LSDTS system to overcome curium backgrounds. However, a neutron generator implemented with an electron accelerator may provide a higher intensity around 1E+13 n/s and it is required to investigate further including a detail analysis. In addition to the neutron generator, a study on target was performed with the Monte Carlo simulation. In the study, an optimal design of target was suggested to provide a high neutron yield and a better thermal resistance. The suggested target consists several cylindrical plates with a certain cooling gap, which have increasing thickness and increasing radius.

  17. 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.

  18. Beam energy variability and other system considerations for a deuteron linac materials research neutron source

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1989-01-01

    There are many overall system aspects and tradeoffs that must be considered in the design of a deuteron linac based neutron source for materials research, in order to obtain a facility with the best possible response to the user's needs, efficient and reliable operation and maintenance, at the optimum construction and operating cost. These considerations should be included in the facility design from the earliest conceptual stages, and rechecked at each stage to insure consistency and balance. Some of system requirements, particularly that of beam energy variability and its implications, are outlined in this talk. (author)

  19. Design considerations for foil windows for PET radioisotope targets

    International Nuclear Information System (INIS)

    Hughey, B.J.; Shefer, R.E.; Klinkowstein, R.E.; Welch, M.J.

    1992-01-01

    This paper describes the results of a study performed at SRL to develop analytical and computational techniques for optimizing the design of conduction-cooled foil windows for PET targets. Single foil conduction cooled windows have been found to be good target entrance windows for both low energy accelerators and medium energy cyclotrons. Detailed thermal analysis has given an approximate analytical expression for the maximum temperature reached in a foil window under conditions of realistic ion beam bombardment. The effects of 'hot spots' in the beam density profile were investigated. It was shown that a factor of two safety margin in window design should be adequate to compensate for any possible beam hot spots. In addition, the reduction of foil stress by slack mounting was verified by experiments. The properties of conventional and novel foil materials were investigated for use in conduction cooled windows. Novel foil materials include two-component Al/Ti and Al/Havar foil. Results on the testing of candidate foil materials for thermal conductivity and mechanical strength at elevated temperature were presented. Two optimum foil window geometries were analyzed: a high aspect ratio window and a multiply slotted window. The multiply slotted window combines the advantages of a high aspect ratio foil window with a circular beam strike and is a promising window design for both TCA and cyclotron targets. A multiply slotted window for a N 2 gas target for 15 O production was designed using the methodologies discussed above. This prototype target was successfully tested using the TCA beam at SRL. (author) 6 figs., 3 tabs., 10 refs

  20. Spatial distribution of moderated neutrons along a Pb target irradiated by high-energy protons

    International Nuclear Information System (INIS)

    Fragopoulou, M.; Manolopoulou, M.; Stoulos, S.; Brandt, R.; Westmeier, W.; Kulakov, B.A.; Krivopustov, M.I.; Sosnin, A.N.; Debeauvais, M.; Adloff, J.C.; Zamani Valasiadou, M.

    2006-01-01

    High-energy protons in the range of 0.5-7.4 GeV have irradiated an extended Pb target covered with a paraffin moderator. The moderator was used in order to shift the hard Pb spallation neutron spectrum to lower energies and to increase the transmutation efficiency via (n,γ) reactions. Neutron distributions along and inside the paraffin moderator were measured. An analysis of the experimental results was performed based on particle production by high-energy interactions with heavy targets and neutron spectrum shifting by the paraffin. Conclusions about the spallation neutron production in the target and moderation through the paraffin are presented. The study of the total neutron fluence on the moderator surface as a function of the proton beam energy shows that neutron cost is improved up to 1 GeV. For higher proton beam energies it remains constant with a tendency to decline

  1. Calculated /alpha/-induced thick target neutron yields and spectra, with comparison to measured data

    International Nuclear Information System (INIS)

    Wilson, W.B.; Bozoian, M.; Perry, R.T.

    1988-01-01

    One component of the neutron source associated with the decay of actinide nuclides in many environments is due to the interaction of decay /alpha/ particles in (/alpha/,n) reactions on low Z nuclides. Measurements of (/alpha/,n) thick target neutron yields and associated neutron spectra have been made for only a few combinations of /alpha/ energy and target nuclide or mixtures of actinide and target nuclides. Calculations of thick target neutron yields and spectra with the SOURCES code require /alpha/-energy-dependent cross sections for (/alpha/,n) reactions, as well as branching fractions leading to the energetically possible levels of the product nuclides. A library of these data has been accumulated for target nuclides of Z /le/ 15 using that available from measurements and from recent GNASH code calculations. SOURCES, assuming neutrons to be emitted isotopically in the center-of-mass system, uses libraries of /alpha/ stopping cross sections, (/alpha/,n) reaction cross reactions, product nuclide level branching fractions, and actinide decay /alpha/ spectra to calculate thick target (/alpha/,n) yields and neutron spectra for homogeneous combinations of nuclides. The code also calculates the thick target yield and angle intergrated neutron spectrum produced by /alpha/-particle beams on targets of homogeneous mixtures of nuclides. Illustrative calculated results are given and comparisons are made with measured thick target yields and spectra. 50 refs., 1 fig., 2 tabs

  2. Energy behaviour of neutrons generated by Witch-type distributed axi-symmetrical deuteron beams accelerated onto plane tritium targets

    International Nuclear Information System (INIS)

    Timus, D.M.; Bradley, D.A.; Timus, B.D.; Kalla, S.L.; Srivastava, H.M.

    2000-01-01

    This paper is an analytical study of the spatial dependency of the d-T neutron energy in the vicinity of a homogeneous tritium-occluded plane target. Close to the target, and along the path of incidence of axially symmetric deuteron beams, the transverse density of accelerated deuterons is assumed to be governed by a law approximated by the 'Witch' function. In particular circumstances, the elementary neutron emission process in non-dispersive media can be considered to be omni-directional (due consideration being paid to collision kinetics, depending upon mass and kinetic energy of particles involved in the nuclear collision, nuclear reaction energy, etc.). Consequently, analytical expressions can be considerably simplified. By applying the classical kinetic energy and momentum conservation laws to nuclear processes, a theoretical description is obtained, taking into account the exoergic character of d-T fusion reaction. A number of expressions for energetic prediction of the fast neutron field are proposed. The associated relations, involving elementary functions, can be investigated using a desk-top computer. Computationally tractable tools are of importance in the study of diverse situations such as induced reactions and activation analysis using 14 MeV neutron generators, investigations in health-physics, radiation dose measurements, nuclear medicine, damage effects, and simulation studies

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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.

  4. 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. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  5. Neutron dose equivalent next to the target shield of a neutron therapy facility using an LET counter

    International Nuclear Information System (INIS)

    Stinchcomb, T.G.; Kuchnir, F.T.

    1981-01-01

    The use of a spherical tissue-equivalent proportional counter for measurements of the lineal energy (y) and derivations of the linear energy transfer (LET) for fast neutrons has the advantage of giving distributions of dose and dose equivalent as functions of either LET or y. A measurement next to the target shielding of the neutron therapy facility at the University of Chicago Hospitals and Clinics (UCHC) is described, and the data processing is outlined. The distributions are presented and compared to those from measurements in the neutron beam. The average quality factors are presented

  6. High neutronic efficiency, low current targets for accelerator-based BNCT applications

    International Nuclear Information System (INIS)

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

    1998-01-01

    The neutronic efficiency of target/filters for accelerator-based BNCT applications is measured by the proton current required to achieve a desirable neutron current at the treatment port (10 9 n/cm 2 /s). In this paper the authors describe two possible targeyt/filter concepts wihch minimize the required current. Both concepts are based on the Li-7 (p,n)Be-7 reaction. Targets that operate near the threshold energy generate neutrons that are close tothe desired energy for BNCT treatment. Thus, the filter can be extremely thin (∼ 5 cm iron). However, this approach has an extremely low neutron yield (n/p ∼ 1.0(-6)), thus requiring a high proton current. The proposed solutino is to design a target consisting of multiple extremely thin targets (proton energy loss per target ∼ 10 keV), and re-accelerate the protons between each target. Targets operating at ihgher proton energies (∼ 2.5 MeV) have a much higher yield (n/p ∼ 1.0(-4)). However, at these energies the maximum neutron energy is approximately 800 keV, and thus a neutron filter is required to degrade the average neutron energy to the range of interest for BNCT (10--20 keV). A neutron filter consisting of fluorine compounds and iron has been investigated for this case. Typically a proton current of approximately 5 mA is required to generate the desired neutron current at the treatment port. The efficiency of these filter designs can be further increased by incorporating neutron reflectors that are co-axial with the neutron source. These reflectors are made of materials which have high scattering cross sections in the range 0.1--1.0 MeV

  7. 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.

  8. Towards a comprehensive system of methodological considerations for cities' climate targets

    International Nuclear Information System (INIS)

    Kramers, Anna; Wangel, Josefin; Johansson, Stefan; Höjer, Mattias; Finnveden, Göran; Brandt, Nils

    2013-01-01

    Climate targets for cities abound. However, what these targets really imply is dependent on a number of decisions regarding system boundaries and methods of calculation. In order to understand and compare cities' climate targets, there is a need for a generic and comprehensive framework of key methodological considerations. This paper identifies eight key methodological considerations for the different choices that can be made when setting targets for GHG emissions in a city and arranges them in four categories: temporal scope of target, object for target setting, unit of target, and range of target. To explore how target setting is carried out in practice, the climate targets of eight European cities were analysed. The results showed that these targets cover only a limited part of what could be included. Moreover, the cities showed quite limited awareness of what is, or could be, include in the targets. This makes comparison and benchmarking between cities difficult. - Highlights: • Cities' climate targets are almost impossible to compare and benchmark. • There is a need for consistent protocols and frameworks supporting target setting. • A framework with key methodological considerations for cities' climate targets is identified. • The framework is used to explore the climate targets for eight European cities. • The difference between production- and consumption based accounting is illustrated in a new way

  9. Target-moderator-reflector optimization for JAERI 5 MW pulsed spallation neutron source

    International Nuclear Information System (INIS)

    Watanabe, Noboru; Teshigawara, Makoto; Kai, Tetsuya

    1999-01-01

    Optimization studies on the target-moderator-reflector neutronics for the projected intense pulsed-spallation-neutron-source in JAERI are reported. In order to obtain the highest possible performance of the source a new target-moderator-reflector system has been proposed and effects of various parameters, such as material and the shape/dimensions of the target, the profile/distribution of the proton beam, material and dimensions of the reflector, the coupling scheme of the target-moderator, moderator parameters, etc., on slow neutron performance and energy deposition in cryogenic moderators have extensively been studied by neutronic calculations. A cold neutron moderator for high-resolution together with high-intensity experiments has newly been proposed. It was found that, by adopting a flat target with a flat beam profile, the slow neutron intensities from the moderators could be rather insensitive to the target/beam dimensions, providing more flexibility to the engineering design of the target and the moderators. The moderator position relative to the target is another important issue to be optimized. It was confirmed that the proposed target-moderator-reflector layout made it possible to put all the moderators almost at the best position (It has not been possible so far), resulting in a higher performance. The predicted performance obtained with nearly optimized parameters was compared with those of similar projects in the world to justify the present concept. (author)

  10. Collimator design for neutron imaging of laser-fusion targets

    International Nuclear Information System (INIS)

    Sommargren, G.E.; Lerche, R.A.

    1981-01-01

    Several pinhole collimator geometries for use in neutron imaging experiments have been modeled and compared. Point spread functions are shown for a cylinder, hyperbola, intersecting cones, and a five-zone approximation to the intersecting cones. Of the geometries studied, the intersecting cones appear the most promising with respect to neutron efficiency, field of view, and isoplanatism

  11. 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.

  12. 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.

  13. 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

  14. Optimisation of the manufacturing process of tritide and deuteride targets used for neutron production

    International Nuclear Information System (INIS)

    Monnin, Carole; Bach, Pierre; Tulle, Pierre Alain; Rompay, Marc van; Ballanger, Anne

    2002-01-01

    As a neutron tube manufacturer, SODERN is now in charge of manufacturing tritium targets for accelerators, in cooperation with CEA/DAM/DTMN in Valduc. Specific deuterium and tritium targets are manufactured on request, according to the requirements of the users, starting from titanium targets on copper substrates, and going to more sophisticated devices. The range of possible uses is wide, including thin targets for neutron calibration, thick targets with controlled loading of deuterium and tritium, rotating targets or large size rotating targets for higher lifetimes. The activity of the targets ranges from 3.7x10 10 to 3.7x10 13 Bq (1-1000 Ci), the diameter being up to 30 cm. Sodern and the CEA/Valduc centre have developed different technologies for tritium target manufacture, allowing the selection of the best configuration for each kind of use. In order to optimize the production of high energy neutrons, the performance of tritide and deuteride titanium targets made by different processes has been studied experimentally by bombardment with 120 and 350 kV deuterons provided by electrostatic accelerators. It is then possible to optimize either neutron output or lifetime and stability or thermal behaviour. The importance of the deposit evaporation conditions on the efficiency of neutron emission is clearly demonstrated, as well as the thermomechanical stability of the Ti thin film under deuteron bombardment. The main parameters involved in the target performance are discussed from a thermodynamical approach

  15. Optimisation of the manufacturing process of tritide and deuteride targets used for neutron production

    Science.gov (United States)

    Monnin, Carole; Bach, Pierre; Tulle, Pierre Alain; van Rompay, Marc; Ballanger, Anne

    2002-03-01

    As a neutron tube manufacturer, SODERN is now in charge of manufacturing tritium targets for accelerators, in cooperation with CEA/DAM/DTMN in Valduc. Specific deuterium and tritium targets are manufactured on request, according to the requirements of the users, starting from titanium targets on copper substrates, and going to more sophisticated devices. The range of possible uses is wide, including thin targets for neutron calibration, thick targets with controlled loading of deuterium and tritium, rotating targets or large size rotating targets for higher lifetimes. The activity of the targets ranges from 3.7×10 10 to 3.7×10 13 Bq (1-1000 Ci), the diameter being up to 30 cm. Sodern and the CEA/Valduc centre have developed different technologies for tritium target manufacture, allowing the selection of the best configuration for each kind of use. In order to optimize the production of high energy neutrons, the performance of tritide and deuteride titanium targets made by different processes has been studied experimentally by bombardment with 120 and 350 kV deuterons provided by electrostatic accelerators. It is then possible to optimize either neutron output or lifetime and stability or thermal behaviour. The importance of the deposit evaporation conditions on the efficiency of neutron emission is clearly demonstrated, as well as the thermomechanical stability of the Ti thin film under deuteron bombardment. The main parameters involved in the target performance are discussed from a thermodynamical approach.

  16. Characteristics of rotating target neutron source and its use in radiation effects studies

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Barschall, H.H.; Booth, R.; Wong, C.

    1975-07-01

    The Rotating Target Neutron Source (RTNS) at Lawrence Livermore Laboratory is currently the most intense source of DT fusion neutrons available for the study of radiation effects in materials. This paper will present a brief description of the machine, outline the history of its development and discuss its performance characteristics and its application to CTR materials research. (U.S.)

  17. Transmutation and neutron flux studies with fission chambers in the MEGAPIE target

    International Nuclear Information System (INIS)

    Chabod, S.; Foucher, Y.; Letourneau, A.; Marie, F.; Toussaint, J.C.; Blandin, Ch.; Chartier, F.; Fioni, G.

    2005-01-01

    Eight fission micro chambers will be inserted inside the central rod of the 1 MW liquid Pb-Bi MEGAPIE target in order to study the transmutation of two major actinides and to measure the neutron flux at a level of 5%. These chambers were developed for high neutron fluxes and tested at Laue Langevin Institute. (authors)

  18. Investigations of fast neutron production by 190 GeV/c muon interactions on graphite target

    CERN Document Server

    Chazal, V; Cook, B; Henrikson, H; Jonkmans, G; Paic, A; Mascarenhas, N; Vogel, P; Vuilleumier, J L

    2002-01-01

    The production of fast neutrons (1 MeV - 1 GeV) in high energy muon-nucleus interactions is poorly understood, yet it is fundamental to the understanding of the background in many underground experiments. The aim of the present experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c muons scattering on carbon target. We have investigated the energy spectrum and angular distribution of spallation neutrons, and we report the result of our measurement of the neutron production differential cross section.

  19. Investigations of fast neutron production by 190 GeV/c muon interactions on different targets

    International Nuclear Information System (INIS)

    Chazal, V.; Boehm, F.; Cook, B.; Henrikson, H.; Jonkmans, G.; Paic, A.; Mascarenhas, N.; Vogel, P.; Vuilleumier, J.-L.

    2002-01-01

    The production of fast neutrons (1 MeV-1 GeV) in high-energy muon-nucleus interactions is poorly understood, yet it is fundamental to the understanding of the background in many underground experiments. The aim of the present experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c muons scattering on carbon, copper and lead targets. We have investigated the energy spectrum and angular distribution of spallation neutrons, and we report the result of our measurement of the neutron production differential cross-section

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  1. Long life neutron generator target using deuterium pass-through structure

    Science.gov (United States)

    Alger, D. L.

    1974-01-01

    Target structure permits all deuterons, except the one-in-a-million that interacts with tritium atom to produce a neutron, to pass completely through target structure and be returned to vacuum system. Since tritium atoms are not displaced as in conventional targets, tritium population will remain unchanged while under deuteron bombardment.

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

    OpenAIRE

    Mishustin, Igor; Malyshkin, Yury; 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. Howeve...

  3. Tritium solid targets for intense D-T neutron production and its related problems

    International Nuclear Information System (INIS)

    Sumita, Kenji

    1988-01-01

    This review paper is divided into three parts. Firstly, to attain an intense neutron production rate, the construction of a design with a higher tritium-containing surface and an effective cooling system like a rotating target device are discussed. The maximum attainable intensity based on tritium solid targets shall be estimated regarding planning for future D-T sources. Secondly, on the way to carry out some experiments, an absolute intensity calibration and an angular dependent neutron energy spectrum of the neutron source are essential parameters to analyse the results of the experiments. Sometimes the space dependent neutron spectrum is required as well as the space dependent neutron flux near the targets and irradiation samples. The measurement methods and their examples are reviewed for tritium solid targets. The third part is devoted to discuss the protection to tritium contamination problems due to unavoidable release of tritium gas from targets. Performance and effectiveness of tritium collection systems for intense D-T neutron sources shall be discussed in some examples. Tritium contamination incidents due to the faulted film powder of target surface are also reported in some real incident cases. (author). Abstract only

  4. A new target concept for proton accelerator driven boron neutron capture therapy applications

    International Nuclear Information System (INIS)

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

    1998-01-01

    A new target concept termed Discs Incorporating Sector Configured Orbiting Sources (DISCOS), is proposed for spallation applications, including BNCT (Boron Neutron Capture Therapy). In the BNCT application a proton beam impacts a sequence of ultra thin lithium DISCOS targets to generate neutrons by the 7 Li(p,n) 7 Be reaction. The proton beam loses only a few keV of its ∼MeV energy as it passes through a given target, and is re-accelerated to its initial energy, by a DC electric field between the targets

  5. Target station design for a 1 MW pulsed spallation neutron source

    International Nuclear Information System (INIS)

    Russell, G.J.; Baker, G.D.; Brewton, R.J.

    1993-01-01

    Target stations are vital components of the 1 MW, next generation spallation neutron source proposed for LANSCE. By and large, target stations design determines the overall performance of the facility. Many traditional concepts will probably have to be rethought, and many new concepts will have to be put forward to meet the 1 MW challenge. This article gives a brief overview of the proposed neutron spallation source from the target station viewpoint, as well as the general philosophy adopted for the design of the LANSCE-II target stations. Some of the saliant concepts and features envisioned for LANSCE-II are briefly described

  6. Target designs for the Brookhaven National Laboratory 5-MW pulsed spallation neutron source

    International Nuclear Information System (INIS)

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

    1996-01-01

    A feasibility study of a compact high power density target for a spallation neutron source was under-taken. The target arrangement consists primarily of heavy metal, with appropriate cooling passages. A high intensity proton beam of intermediate energy is directed at the target, where it interacts with the heavy metal nuclei. The subsequent spallation reactions produce several neutrons per proton resulting in an intense neutron source. The proton beam is assumed to havean energy of 5 MW, and to be cyclic with a repetition rate of 10Hz and 50Hz. The study was divided into two broad sections. First, an analysis of preliminary target designs was undertaken to ensure the overall feasibility of the concepts involved in the design and eventual construction of such a high power density target. Second, two proposed target designs, based on the first set of analyses, are investigated in more detail. Special care is taken to ensure that the neutron fluxes in the moderator are at the desired level no material compatibility problems exist,and the target is able to operate in a reliable and safe manner. Several target materials, coolant types, and target arrangements are investigated in the first section. The second section concentrates on a single target material and geometric arrangement. However, several structural material choices continue to be investigated with the aim of minimizing the effects of structural heating, and associated thermally induced stresses. In the final section the conclusions of this preliminary study are summarized

  7. Neutron yield from thick lead target by the action of high-energy electrons

    International Nuclear Information System (INIS)

    Noga, V.I.; Ranyuk, Yu.N.; Telegin, Yu.N.; Sorokin, P.V.

    1978-01-01

    The results are presented of studying the complete neutron yield from a lead target bombarded by high-energy electrons. Neutrons were recorded by the method of radio-active indicators. The dependence of the neutron yield on the target thickness varying from 0.2 to 8 cm was obtained at the energies of electrons of 230 and 1200 MeV. The neutron yield for the given energies with the target of 6 cm in thickness is in the range of saturation and is 0.1 +-0.03 and 0.65+-0.22 (neutr./MeV.el.), respectively. The neutron angular distributions were measured for different thicknesses of targets at the 201, 230 and 1200 MeV electrons. Within the error limits the angular distributions are isotropic. The dependence of neutron yield on the electron energy was examined for a 3 cm thick target. In the energy range of 100-1200 MeV these values are related by a linear dependence with the proportionality coefficient C=3x10 -4 (neutr./MeV.el.)

  8. HIGH SPATIAL RESOLUTION IMAGING OF INERTIAL FUSION TARGET PLASMAS USING BUBBLE NEUTRON DETECTORS

    International Nuclear Information System (INIS)

    FISHER, R.K.

    2003-01-01

    OAK B202 HIGH SPATIAL RESOLUTION IMAGING OF INERTIAL FUSION TARGET PLASMAS USING BUBBLE NEUTRON DETECTORS. Bubble detectors, which can detect neutrons with a spatial 5 to 30 (micro), are the most promising approach to imaging NIF target plasmas with the desired 5 (micro) spatial resolution in the target plane. Gel bubble detectors are being tested to record neutron images of ICF implosions in OMEGA experiments. By improving the noise reduction techniques used in analyzing the data taken in June 2000, we have been able to image the neutron emission from 6 · 10 13 yield DT target plasmas with a target plane spatial resolution of ∼ 140 (micro). As expected, the spatial resolution was limited by counting statistics as a result of the low neutron detection efficiency of the easy-to-use gel bubble detectors. The results have been submitted for publication and will be the subject of an invited talk at the October 2001 Meeting of the Division of Plasma Physics of the American Physical Society. To improve the counting statistics, data was taken in May 2001 using a stack of four gel detectors and integrated over a series of up to seven high-yield DT shots. Analysis of the 2001 data is still in its early stages. Gel detectors were chosen for these initial tests since the bubbles can be photographed several hours after the neutron exposure. They consist of ∼ 5000 drops (∼ 100 (micro) in diameter) of bubble detector liquid/cm 3 suspended in an inactive support gel that occupies ∼ 99% of the detector volume. Using a liquid bubble chamber detector and a light scattering system to record the bubble locations a few microseconds after the neutron exposure when the bubbles are ∼ 10 (micro) in diameter, should result in ∼ 1000 times higher neutron detection efficiency and a target plane resolution on OMEGA of ∼ 10 to 50 (micro)

  9. Neutron energy spectrum from 120 GeV protons on a thick copper target

    Energy Technology Data Exchange (ETDEWEB)

    Shigyo, Nobuhiro; /Kyushu U.; Sanami, Toshiya; /KEK, Tsukuba; Kajimoto, Tsuyoshi; /Kyushu U.; Iwamoto, Yosuke; /JAEA, Ibaraki; Hagiwara, Masayuki; Saito, Kiwamu; /KEK, Tsukuba; Ishibashi, Kenji; /Kyushu U.; Nakashima, Hiroshi; Sakamoto, Yukio; /JAEA, Ibaraki; Lee, Hee-Seock; /Pohang Accelerator Lab.; Ramberg, Erik; /Fermilab

    2010-08-01

    Neutron energy spectrum from 120 GeV protons on a thick copper target was measured at the Meson Test Beam Facility (MTBF) at Fermi National Accelerator Laboratory. The data allows for evaluation of neutron production process implemented in theoretical simulation codes. It also helps exploring the reasons for some disagreement between calculation results and shielding benchmark data taken at high energy accelerator facilities, since it is evaluated separately from neutron transport. The experiment was carried out using a 120 GeV proton beam of 3E5 protons/spill. Since the spill duration was 4 seconds, protoninduced events were counted pulse by pulse. The intensity was maintained using diffusers and collimators installed in the beam line to MTBF. The protons hit a copper block target the size of which is 5cm x 5cm x 60 cm long. The neutrons produced in the target were measured using NE213 liquid scintillator detectors, placed about 5.5 m away from the target at 30{sup o} and 5 m 90{sup o} with respect to the proton beam axis. The neutron energy was determined by time-of-flight technique using timing difference between the NE213 and a plastic scintillator located just before the target. Neutron detection efficiency of NE213 was determined on basis of experimental data from the high energy neutron beam line at Los Alamos National Laboratory. The neutron spectrum was compared with the results of multiparticle transport codes to validate the implemented theoretical models. The apparatus would be applied to future measurements to obtain a systematic data set for secondary particle production on various target materials.

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

    International Nuclear Information System (INIS)

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

    2013-06-01

    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 3 He 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. (authors)

  11. Neutron energy spectra produced by α-bombardment of light elements in thick targets

    International Nuclear Information System (INIS)

    Jacobs, G.J.H.

    1982-01-01

    The aim of the work, presented in this thesis, is to determine energy spectra of neutrons produced by α-particle bombardment of thick targets containing light elements. These spectra are required for nuclear waste management. The set-up of the neutron spectrometer is described, and its calibration discussed. Absolute efficiencies were determined at various neutron energies, using monoenergetic neutrons produced with the Van de Graaff accelerator in pulsed mode. The additional calibration of the neutron spectrometer as proton-recoil spectrometer was carried out primarily for future applications in measurements where no pulsed neutron source is available or the neutron flux density is too low. The basis for an accurate uncertainty analysis is made by the determination of the covariance matrix for the uncertainties in the efficiencies. The determination of the neutron energy spectra from time-of-flight and from proton-recoil measurements is described. A comparison of the results obtained from the two different types of measurements is made. The experimentally determined spectra were compared with spectra calculated from stopping powers and theoretically determined cross sections. These cross sections were calculated from optical model parameters and level parameters using the Hauser-Feshbach formalism. Measurements were carried out on thick targets of silicon, aluminium, magnesium, carbon, boron nitride, calcium fluoride, aluminium oxide, silicon oxide and uranium oxide at four different α-particle energies. (Auth.)

  12. Projectile fragmentation of neutron-rich nuclei on light target (momentum distribution and nucleon-removal cross section)

    International Nuclear Information System (INIS)

    Kobayashi, T.; Tanihata, I.; Suzuki, T.

    1992-01-01

    Transverse momentum distributions of the projectile fragments from β-unstable nuclei have been measured with various projectile and target combinations. The momentum correlation of two neutrons in the neutron halo is extracted from the P c t distribution of 9 Li and hat of the neutrons. It is found that the two neutrons are moving in the same direction on average and thus strongly suggests the formation of a di-neutron in 11 Li. (Author)

  13. Consideration of LH2 and LD2 cold neutron sources in heavy water reactor reflector

    International Nuclear Information System (INIS)

    Potapov, I.A.; Serebrov, A.P.

    2001-01-01

    The reactor power, the required CNS dimensions and power of the cryogenic equipment define the CNS type with maximized cold neutron production. Cold neutron fluxes from liquid hydrogen (LH 2 ) and liquid deuterium (LD 2 ) cold neutron sources (CNS) are analyzed. Different CNS volumes, presents and absence of reentrant holes inside the CNS, different adjustment of beam tube and containment are considered. (orig.)

  14. A D-D neutron generator using a titanium drive-in target

    International Nuclear Information System (INIS)

    Kim, I.J.; Jung, N.S.; Jung, H.D.; Hwang, Y.S.; Choi, H.D.

    2008-01-01

    A D-D neutron generator was developed with an intensity of 10 8 n/s. A helicon plasma ion source was used to produce a large current deuteron beam, and neutrons were generated by irradiating the deuteron beam on a titanium drive-in target made of commercial pure titanium. The neutron generator was test-run for several hundred hours, and the performances were investigated. The available range of the deuteron beam current was 0.8-8 mA and the beam could be accelerated up to 97.5 keV. The maximum neutron generation rate in the test-runs was 1.9 x 10 8 n/s, which was achieved by irradiating a 7.6 mA deuteron beam at 94.0 keV on a 0.5 mm-thick target. The operation of the neutron generator was fairly stable, such that the neutron generation rate was not altered by high voltage breakdowns during the test-runs. Neutron generation efficiency was rated as low as 10% when compared to an ideal case of irradiating a 100% monatomic deuteron beam on a perfect TiD 2 target. Factors causing the low efficiency were suggested and discussed

  15. Production, separation and target preparation of {sup 171}Tm and {sup 147}Pm for neutron cross section measurements

    Energy Technology Data Exchange (ETDEWEB)

    Heinitz, Stephan; Maugeri, Emilio A.; Schumann, Dorothea; Dressler, Rugard; Kivel, Niko [Paul Scherrer Institute, Villigen (Switzerland); Guerrero, Carlos [Sevilla Univ. (Spain); Koester, Ullrich [Institut Laue-Langevin, Grenoble (France); Tessler, Moshe; Paul, Michael [Hebrew Univ. of Jerusalem (Israel); Halfon, Shlomi [Soreq Nuclear Research Center, Yavne (Israel); Collaboration: nTOF Collaboration

    2017-07-01

    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 {sup 171}Tm from 240 mg {sup 170}Er{sub 2}O{sub 3} and 72 μg {sup 147}Pm from 100 mg {sup 146}Nd{sub 2}O{sub 3} irradiated at the ILL high flux reactor. Thin targets were prepared with high chemical and radioisotopic purity suitable for neutron capture measurements at nTOF CERN and the SARAF-LiLiT facility.

  16. 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.

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

    International Nuclear Information System (INIS)

    Rapp, Juergen; Aaron, A. M.; Bell, Gary L.; Burgess, Thomas W.; Ellis, Ronald James; Giuliano, D.; Howard, R.; Kiggans, James O.; Lessard, Timothy L.; Ohriner, Evan Keith; Perkins, Dale E.; Varma, Venugopal Koikal

    2015-01-01

    5-20 MW/m"2 and ion fluxes up to 10"2"4 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.

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

    OpenAIRE

    Halfon, S.; Arenshtam, A.; 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 ...

  19. 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.

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

    International Nuclear Information System (INIS)

    Robouch, P.; Arana, G.; Eguskiza, M.; Maguregui, M.I.; Pomme, 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Mishustin, Igor, E-mail: mishustin@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); “Kurchatov Institute”, National Research Center, 123182 Moscow (Russian Federation); Malyshkin, Yury, E-mail: malyshkin@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow (Russian Federation); Pshenichnov, Igor, E-mail: pshenich@fias.uni-frankfurt.de [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany); Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow (Russian Federation); Greiner, Walter [Frankfurt Institute for Advanced Studies, J.-W. Goethe University, 60438 Frankfurt am Main (Germany)

    2015-04-15

    A possibility of synthesizing neutron-rich superheavy 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 {sup 249}Bk 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 could turn ADS into an alternative source of transuranic elements in addition to nuclear fission reactors.

  2. Liquid lithium target as a high intensity, high energy neutron source

    Science.gov (United States)

    Parkin, Don M.; Dudey, Norman D.

    1976-01-01

    This invention provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then "boil off" or evaporate a neutron.

  3. Liquid lithium target as a high intensity, high energy neutron source

    International Nuclear Information System (INIS)

    Parkin, D.M.; Dudey, N.D.

    1976-01-01

    The invention described provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then ''boil off'' or evaporate a neutron

  4. 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)

  5. Interaction of 14 MeV neutrons with hydrogenated target proton emission calculation

    International Nuclear Information System (INIS)

    Martin, G.; Perez, N.; Desdin.

    1996-01-01

    Using neutron emission data of a 14 MeV neutron generator, a paraffin target, and based on the n + H 1 → n '+ p reaction, have been obtained the characteristics of the proton emission in a proton-neutron mixed field. It was used Monte Carlo simulation and it was obtained the proton output as function of the converter width and the energy spectrum of protons corresponding to different converter thickness. Among 0.07 and 0.2 cm there is a maximum zone for the proton emission. The energy spectrum agrees with obtained on previous papers. Figures showing these results are provided

  6. Neutron pre-emission at the fusion of 11 Li halo nuclei with Si targets

    International Nuclear Information System (INIS)

    Petrascu, M.; Isbasescu, A.; Petrascu, H.; Bordeanu, C.; David, I.; Lazar, I.; Mihai, I.; Vaman, G.; Tanihata, I.; Kobayashi, T.; Korsheninnikov, A.; Fukuda, S.; Kumagai, H.; Momota, S.; Ozawa, A.; Yoshida, K.; Nikolski, E.; Giurgiu, M.

    1997-01-01

    In this contribution, the first experiment on fusion of 11 Li halo nuclei with Si targets is reported. A novel effect consisting of a large neutron pre-emission probability in the fusion process was observed. The neutron halo nuclei are characterized by very large matter radii, small separation energy and small internal momentum of the valence neutrons. Until now, the halo nuclei were investigated mostly by elastic, inelastic scattering and breakup processes. It was recently predicted that due to the very large dimension of 11 Li, one may expect, that in a fusion experiment on a light target, the valence neutrons will not be absorbed together with the 9 Li core, but will be emitted in the early stage of the reaction process. The experiment aiming to check this expectation, performed at RIKEN-RIPS facility, is described. In the experimental arrangement, three main parts are present: the first part contains the detectors used for the control, identification and determination of the beam characteristics; the second part consists of a Multiple Sampling Ionisation Chamber (MUSIC), used for identification of the inclusive evaporation residue spectra produced in the detector-target; the third part consists of two wall neutron detectors, each made up of 15 plastic scintillators. This detector was used for the energy and position determination of the neutrons originating from the target. The projectile energy range was 11.2 - 15.2 AMeV, centered at 13 AMeV. The neutrons resulting from the reaction were measured by time-of-light technique. The position on the 'wall' of the detected neutrons could be also determined. The measured neutron spectra from 11 Li and 9 Li are shown. A marked different between the two spectra was found and it is explained by the contribution of a large amount of pre-emission (breakup) processes, in case of 11 Li projectiles. The position spectra point out the evaporation origin of the neutrons in case of 9 Li projectiles while for 11 Li only the

  7. A monocrystal of 59Co as a nuclear orientation thermometer in neutron experiments with oriented targets

    International Nuclear Information System (INIS)

    Fasoli, U.; Galeazzi, G.; Pavan, P.; Toniolo, D.; Zago, G.; Zannoni, R.

    1980-01-01

    An apparatus for measuring temperatures in the millikelvin region is described based on the 'deformation effect' on fast neutron transmission through an aligned 59 Co monocrystal, employing a 252 Cf pill as the neutron source. A statistical accuracy of a few percent in a few minutes is obtainable with a heat input of some tens of pW. The apparatus is suitable in neutron experiments with oriented targets when the gamma-ray background hinders the use of gamma-ray anisotropy thermometers. In these and similar cases, in which the temperature must be held constant for long periods, the large heat capacity of the cobalt sample is not a drawback. (orig.)

  8. Fiscal year 1976 DT fusion neutron irradiations and dosimetry at the LLL rotating target neutron source

    International Nuclear Information System (INIS)

    MacLean, S.C.

    1977-01-01

    The DT fusion neutron irradiation of 319 samples during 19 irradiation periods (beam-on time of more than 1026 hours) is described. Experiments from 24 individuals representing 11 institutions are summarized. The numbers of the UCID dosimetry reports detailing each of the irradiations are given

  9. Parametric studies of target/moderator configurations for the Weapons Neutron Research (WNR) facility

    International Nuclear Information System (INIS)

    Russell, G.J.; Seeger, P.A.; Fluharty, R.G.

    1977-03-01

    Parametric studies, using continuous-energy Monte Carlo codes, were done to optimize the neutronics of the Weapons Neutron Research (WNR) target and three possible target/moderator configurations: slab target/slab moderators, cylindrical target/cylindrical moderator, and cylindrical target/double-wing moderators. The energy range was 0.5 eV to 800 MeV. A general figure-of-merit (FOM) approach was used. The WNR facility performance can be doubled or tripled by optimizing the target and target/moderator configurations; this approach is more efficient than increasing the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator power by an equivalent factor. A bare target should be used for neutron energies above approximately 100 keV. The FOM for the slab target/slab moderator configuration is the best by a factor of at least 2 to 3 below approximately 1 keV. The total neutron leakage from 0.5 eV to 100 keV through a 100- by 100-mm area centered at the peak leakage is largest for the slab moderator, exceeding that of the cylindrical moderator and double-wing moderator by factors of 1.7 and 3.4, respectively. The neutron leakage at 1 eV from one 300- by 150-mm surface of a slab moderator is 1.5 times larger than that from one 155- by 150-mm surface of a cylindrical moderator. When compared with the 1-eV leakage from two 100- by 150-mm surfaces of a double-wing moderator, that from the slab moderator is 3.4 times larger. 107 figures, 13 tables

  10. Influence of neutron energy on formation of radioisotopes during the irradiation of targets in reactor

    Directory of Open Access Journals (Sweden)

    P. M. Vorona

    2011-09-01

    Full Text Available Method of calculation of nuclear transformations in irradiated targets is realized for selection of optimal conditions for accumulation of radioisotopes in reactor, taking into account contributions of different energy neutrons (thermal, resonance and fast. Wide potentialities of program complex MCNP-4C based on the method of statistical testing (Monte Carlo method were used. Positive in proposed method is that all calculations starting from spectra and fluxes of neutrons in reactor and completing by quantity of accumulating nuclei carry out within the framework of the same methodological approach. It was shown by the example of radioactive 98Mo production in Mo98Mo(n, γ99Mo reaction that for achievement of maximal yield of target radionuclide. it is necessary to irradiate start targets of Molybdenum in hard spectrum with essential contribution of resonance neutrons.

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

    International Nuclear Information System (INIS)

    Ghiglino, A.; Terrón, S.; Thomsen, K.; Wolters, J.; Magán, M.; Martínez, F.; Vicente, P.J. de; Vivanco, R.; Sordo, F.; Butzek, M.; Perlado, J.M.; Bermejo, F.J.

    2014-01-01

    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

  12. Neutron Production from In-situ Heavy Ice Coated Targets at Vulcan

    Science.gov (United States)

    Morrison, John; Krygier, A. G.; Kar, S.; Ahmed, H.; Alejo, A.; Clarke, R.; Fuchs, J.; Green, A.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.

    2015-05-01

    Laser based neutron production experiments have been performed utilizing ultra-high intensity laser accelerated ions impinging upon a secondary target. The neutron yield from such experiments may be improved if the accelerated ions were primarily deuterons taking advantage of the d-d cross section. Recent experiments have demonstrated that selective deuteron acceleration from in-situ heavy ice coating of targets can produce ion spectra where deuterons comprise > 99 % of the measured ions. Results will be presented from integrated neutron production experiments from heavy ice targets coated in-situ recently performed on the Vulcan laser at Rutherford Appleton Laboratory. We are grateful for the Staff at RAL and acknowledge funding from the US DoE. AFOSR, European Social Fund, and the Czech Republic.

  13. Scientific opportunities at SARAF with a liquid lithium jet target neutron source

    Science.gov (United States)

    Silverman, Ido; Arenshtam, Alex; Berkovits, Dan; Eliyahu, Ilan; Gavish, Inbal; Grin, Asher; Halfon, Shlomi; Hass, Michael; Hirsh, T. Y.; Kaizer, Boaz; Kijel, Daniel; Kreisel, Arik; Mardor, Israel; Mishnayot, Yonatan; Palchan, Tala; Perry, Amichay; Paul, Michael; Ron, Guy; Shimel, Guy; Shor, Asher; Tamim, Noam; Tessler, Moshe; Vaintraub, Sergey; Weissman, Leo

    2018-05-01

    SARAF (Soreq Applied Research Accelerator Facility) is based on a 5 mA, 40 MeV, proton/deuteron accelerator. Phase-I, operational since 2010, provides proton and deuteron beams up to 4 and 5 MeV, respectively, for basic and applied research activities. The high power Liquid-Lithium jet Target (LiLiT), with 1.912 MeV proton beam, provides high flux quasi-Maxwellian neutrons at kT 30 keV (about 2 × 1010 n/s/cm2/mA on the irradiated sample, about 1 cm from the target), enabling studies of s-process reactions relevant to nucleo-synthesis of the heavy elements in giant AGB stars. With higher energy proton beams and with deuterons, LiLiT can provide higher fluxes of high energy neutrons up to 20 MeV. The experimental program with SARAF phase-I will be enhanced shortly with a new target room complex which is under construction. Finally, SARAF phase-II, planned to start operation at 2023, will enable full capabilities with proton/ deuteron beams at 5 mA and 40 MeV. Liquid lithium targets will then be used to produce neutron sources with intensities of 1015 n/s, which after thermalization will provide thermal neutron (25 meV) fluxes of about 1012 n/s/cm2 at the entrance to neutron beam lines to diffraction and radiography stations.

  14. Los Alamos pulsed spallation neutron source target systems - present and future

    International Nuclear Information System (INIS)

    Russell, G.J.; Daemen, L.L.; Pitcher, E.J.; Brun, T.O.; Hjelm, R.P. Jr.

    1993-01-01

    For the past 16 yr, spallation target-system designers have devoted much time and effort to the design and optimization of pulsed spallation neutron sources. Many concepts have been proposed, but, in practice, only one has been implemented horizontal beam insertion with moderators in wing geometry i.e., until we introduced the innovative split-target/flux-trap-moderator design with a composite reflector shield at the Manuel Lujan, Jr., Neutron Scattering Center (LANSCE). The LANSCE target system design is now considered a classic by spallation target system designers worldwide. LANSCE, a state-of-the-art pulsed spallation neutron source for materials science and nuclear physics research, uses 800-MeV protons from the Clinton P. Anderson Meson Physics Facility. These protons are fed into the proton storage ring to be compressed to 250-ns pulses before being delivered to LANSCE at 20 Hz. LANSCE produces the highest peak neutron flux of any pulsed spallation neutron source in the world

  15. Fusion neutron generation by high-repetitive target injection

    International Nuclear Information System (INIS)

    Kitagawa, Yoneyoshi

    2015-01-01

    Pellet injection and repetitive laser illumination are key technologies for realizing inertial fusion energy. The Graduate School for the Creation of New Photonics Industries, Hamamatsu Photonics K. K. and Toyota Motor Corporation demonstrate the pellet injection, counter laser beams' engagement and neutron generation. Deuterated polystyrene (CD) bead pellets, after free-falling for a distance of 18 cm at 1 Hz, are successfully engaged by two counter laser beams from a diode-pumped, ultra-intense laser HAMA. The laser energy, pulse duration, wavelength and the intensity are 0.63 J per beam, 104 fs, 811 nm and 4.7 x 10 18 W/cm 2 , respectively. The irradiated pellets produce D (D, n) 3 He-reacted neutrons with a maximum yield of 9.5 x 10 4 /4π sr/shot. A straight channel with 10 μm-diameter is found through the beads. The pellet size is 1 mm. The results indicate potentially useful technologies for the next step in realizing inertial fusion energy. The results are reviewed as well as some oversea activities. (author)

  16. Targeted Modification of Neutron Energy Spectra for National Security Applications

    Science.gov (United States)

    Bevins, James Edward

    At its core, research represents an attempt to break from the "this is the way we have always done it" paradigm. This idea is evidenced from the start in this research effort by the problem formulation to develop a new way to generate synthetic debris that mimics the samples that would be collected for forensics purposes following a nuclear weapon attack on the U.S. or its allies. The philosophy is also demonstrated by the design methodology used to solve the synthetic debris problem, using methods not commonly applied to nuclear engineering problems. Through this research, the bounds of what is deemed possible in neutron spectral shaping are moved ever so slightly. A capability for the production of synthetic debris and fission products was developed for the National Ignition Facility (NIF). Synthetic debris has historically been made in a limited fashion using sample doping techniques since the cessation of nuclear weapons testing, but a more robust alternative approach using neutron spectral shaping was proposed and developed by the University of California-Berkeley and Lawrence Livermore National Laboratory (LLNL). Using NIF as a starting source spectrum, the energy tuning assembly (ETA) developed in this work can irradiate samples with a combined thermonuclear and prompt fission neutron spectrum (TN+PFNS). When used with fissile foils, this irradiation will produce a synthetic fission product distribution that is realistic across all mass chains. To design the ETA, traditional parametric point design approaches were discarded in favor of formal optimization techniques. Finding a lack of suitable algorithms in the literature, a metaheuristic-based optimization algorithm, Gnowee, was developed for rapid convergence to nearly globally optimum solutions for complex, constrained engineering problems with mixed-integer and combinatorial design vectors and high-cost, noisy, discontinuous, black box objective function evaluations. Comparisons between Gnowee and

  17. Cold neutron interaction with a classical electric field: Some basic theoretical and experimental considerations

    International Nuclear Information System (INIS)

    Bruce, S.; Diaz-Valdes, J.; Bennun, L.; Minning, P.C.

    2008-01-01

    We explore the feasibility of performing an experiment to measure the interaction of cold neutrons with a given classical electric field. Bound and scattering states could be detected by means of an approximate Aharonov-Casher configuration. The theoretical background is presented and then some primary elements for building a neutron detector of this nature are proposed

  18. The powder targets of hard materials for neutron halo studies

    International Nuclear Information System (INIS)

    Stolarz, A.

    1997-01-01

    The powder sedimentation from a glue solution has been used for preparation of the thick targets of high melting point elements. This technique is particularly suitable for expensive enriched isotopic materials available in very limited amount. The targets of 96 Ru, 104 Ru, 130 Te, 183 W, 192 Os with thickness range of 25-65 mg/cm 2 were prepared by this method. The target thickness uniformity was examined by X-ray absorption and variations less than 10% were found. (orig.)

  19. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Osipenko, M., E-mail: osipenko@ge.infn.it [INFN, sezione di Genova, 16146 Genova (Italy); Ripani, M. [INFN, sezione di Genova, 16146 Genova (Italy); Alba, R. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Ricco, G. [INFN, sezione di Genova, 16146 Genova (Italy); Schillaci, M. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Barbagallo, M. [INFN, sezione di Bari, 70126 Bari (Italy); Boccaccio, P. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Celentano, A. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy); Colonna, N. [INFN, sezione di Bari, 70126 Bari (Italy); Cosentino, L.; Del Zoppo, A.; Di Pietro, A. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Esposito, J. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Figuera, P.; Finocchiaro, P. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Kostyukov, A. [Moscow State University, Moscow 119992 (Russian Federation); Maiolino, C.; Santonocito, D.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Viberti, C.M. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy)

    2013-09-21

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

  1. CFD analysis of a liquid mercury target for the National Spallation Neutron Source

    International Nuclear Information System (INIS)

    Wendel, M.W.; Tov, M.S.

    1997-01-01

    Computational fluid dynamics (CFD) is being used to analyze the design of the National Spallation Neutron Source (NSNS) target. The target is subjected to the neutronic (internal) heat generation that results from the proton collisions with the mercury nuclei. The liquid mercury simultaneously serves as the neutronic target medium, transports away the heat generated within itself, and cools the metallic target structure. Recirculation and stagnation zones within the target are of particular concern because of the likelihood that they will result in local hot spots. These zones exist because the most feasible target designs include a complete U-turn flow redirection. Although the primary concern is that the target is adequately cooled, the pressure drop from inlet to outlet must also be considered because pressure drop directly affects structural loading and required pumping power. Various design options have been considered in an effort to satisfy these design criteria. Significant improvements to the design have been recommended based on the results. Detailed results are presented for the current target design including a comparison with published pressure-drop data. Comparisons are also made with forced convection heat transfer data for liquid mercury flow in circular tubes

  2. Status of the Spallation Neutron Source with focus on target materials

    International Nuclear Information System (INIS)

    Mansur, L.K.; Haines, J.R.

    2006-01-01

    An overview of the design and construction of the Spallation Neutron Source (SNS) is presented. Key facility performance parameters are summarized and plans for initial operation are described. Early efforts produced a conceptual design in 1997; the project itself was initiated in 1999, with the official groundbreaking taking place in December of 1999. As of April 2005 building construction was complete and the overall project was more than 90% complete. The design of the target and surrounds are finished and the first target was installed in June 2005. First beam on target is expected in June, 2006. The engineering design of the target region is described. The key systems comprise the mercury target, moderator and reflector assemblies, remote handling systems, utilities and shielding. Through interactions with the 1 GeV proton beam, the target, moderators and reflectors produce short pulse neutrons in thermal energy ranges, which are transported to a variety of neutron scattering instruments. The mercury target module itself is described in more detail. Materials issues are expected to govern the overall lifetime and have influenced the design, fabrication and planned operation. A wide range of materials research and development has been carried out to provide experimental data and analyses to ensure the satisfactory performance of the target and to set initial design conditions. Materials R and D concentrated mainly on cavitation erosion, radiation effects, and mercury compatibility issues, including investigations of the mechanical properties during exposure to mercury. Questions that would require future materials research are discussed

  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. 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.

  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. Dynamically polarized hydrogen target as a broadband, wavelength-independent thermal neutron spin polarizer

    International Nuclear Information System (INIS)

    Zhao Jinkui; Garamus, Vasil M.; Mueller, Wilhelm; Willumeit, Regine

    2005-01-01

    A hydrogen-rich sample with dynamically polarized hydrogen nuclei was tested as a wavelength-independent neutron transmission spin polarizer. The experiment used a modified setup of the dynamic nuclear polarization target station at the GKSS research center. The standard solvent sample at the GKSS DNP station was used. It is 2.8mm thick and consists of 43.4wt% water, 54.6wt% glycerol, and 2wt% of EHBA-Cr(v) complex. The wavelength of the incident neutrons for the transmission experiment was λ=8.1A with Δλ/λ=10%. The polarization of neutron beam after the target sample was analyzed with a supermirror analyzer. A neutron polarization of -52% was achieved at the hydrogen polarization of -69%. Further experiments will test the feasibility of other hydrogen-rich materials, such as methane, as the polarizer. A theoretical calculation shows that a polarized methane target would allow over 95% neutron polarizations with more than 30% transmission

  7. The applicaton of neutron radioscopy to lithium-aluminum alloy target elements

    International Nuclear Information System (INIS)

    Antal, J.J.; Marotta, A.S.; Salaymeh, S.R.; Varallo, T.P.

    1989-01-01

    The authors show that neutron radioscopy is very useful in locating the position of a Li-A1 alloy core enriched in Lithium-6 in tubular aluminum target elements. The alloy core is displaced during a forming process and its location must be redetermined before processing can be completed. A low-flux mobile neutron radioscopy system was employed in these studies as a model system for possible on-line, in-plant use. A series of core end sections of target tubes containing from 0.1 to 4.6 grams of Lithium-6 per foot of length were examined radioscopically with thermal neutrons. The system was able to determine the extent of lithium alloy core from the highest concentrations down to about 0.2 grams of Lithium-6 per ft within one minute of data collection time

  8. 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.

  9. Calculational estimations of neutron yield from ADS target

    International Nuclear Information System (INIS)

    Degtyarev, I.I.; Liashenko, O.A.; Yazynin, I.A.; Belyakov-Bodin, V.I.; Blokhin, A.I.

    2002-01-01

    Results of computational studies of high power spallation thick ADS (Accelerator-Driven System) targets with 0.8-1.2 GeV proton beams are given. Comparisons of experiments and calculations of double differential and integral n/p yield are also described. (author)

  10. EURISOL-DS Multi-MW Target Neutronic Calculations for the Baseline Configuration of the Multi-MW Target

    CERN Document Server

    Herrera-Martínez, A

    2006-01-01

    This document summarises the study performed within the Task #2 of the European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL DS) [1] to design the Multi-MW proton-to-neutron converter. A preliminary study [2] was carried out in order to understand the nature of the interactions taking place in the proton-to-neutron converter and their impact on the design of the facility. Namely, the target dimensions and material composition, type of incident particle, its energy and the beam profile were analysed in the aforementioned technical note, and their optimum values were suggested in the conclusions. The present work is based on the results of the previous study and uses the same methodology, namely Monte Carlo simulations with FLUKA [3]. This note describes the performance of a Hg target design and addresses more detailed issues, such as the composition of the fission target and use of a neutron reflector. It also attempts to integrate those components together and estimate the wh...

  11. Neutron production in lead targets by high-energy light-mass heavy ions

    International Nuclear Information System (INIS)

    Daniehl', A.V.; Lyapin, V.S.; Tsvetkov, I.O.

    1992-01-01

    The characteristics of the time-of-flight spectrometer and the double different distributions of neutrons and secondary charged particles produced by 2 GeV protons and 1 GeVXA d,α, 6 Li and 12 C ions bombarding lead targets are described. Experimental data are compared with the results of calculations by codes SITHA. 17 refs.; 10 figs.; 1 tab

  12. Status of SINQ, the only MW spallation neutron source-highlighting target development and industrial applications

    International Nuclear Information System (INIS)

    Wagner, Werner; Dai, Yong; Glasbrenner, Heike; Grosse, Mirco; Lehmann, Eberhard

    2006-01-01

    SINQ is a continuous spallation neutron source, driven by PSI's 590 MeV proton accelerator. Receiving a stable proton current of 1.3 mA, SINQ is the presently most powerful accelerator-driven facility worldwide. Besides the primary designation of SINQ to serve as user facility for neutron scattering and neutron imaging, PSI seeks to play a leading role in the development of the facility, focusing on spallation targets and materials research for high-dose radiation environments. Accompanying these activities, SINQ has established several projects serving a more general, profound development towards high-power spallation targets: the most prominent ones being SINQ Target Irradiation Program (STIP) and megawatt pilot experiment for a liquid metal target (MEGAPIE), complemented by LiSoR and VIMOS. Within the user program, SINQ is aspiring to attract an appropriate contingent of industrial applications. The paper highlights the potential for industrial applications by means of selected examples from strain mapping and neutron imaging

  13. Thermal analysis of titanium drive-in target for D-D neutron generation.

    Science.gov (United States)

    Jung, N S; Kim, I J; Kim, S J; Choi, H D

    2010-01-01

    Thermal analysis was performed for a titanium drive-in target of a D-D neutron generator. Computational fluid dynamics code CFX-5 was used in this study. To define the heat flux term for the thermal analysis, beam current profile was measured. Temperature of the target was calculated at some of the operating conditions. The cooling performance of the target was evaluated by means of the comparison of the calculated maximum target temperature and the critical temperature of titanium. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. Precise measurements of the thick target neutron yields of the 7Li(p,n) reaction

    International Nuclear Information System (INIS)

    Matysiak, W.; Prestwich, W.V.; Byun, S.H.

    2011-01-01

    Thick target neutron yield of the 7 Li(p,n) 7 Be reaction was measured in the proton energy range from 1.95 to 2.3 MeV by determining induced activity of the 7 Be. A HPGe detector was used to detect the 478 keV gamma-rays emitted through 7 Be decay. A series of irradiations with nominal proton energies of 1.95, 2.0, 2.1, 2.2, and 2.3 MeV were carried out. In an independent experiment, raw neutron spectra were collected by a 3 He ion chamber for the same series of proton energies. From the raw neutron spectra, it was noted, that the effective proton energies were lower than the nominal by 50-58 keV. After corrections for the proton energy offsets were applied, the measured neutron yields matched the analytically calculated yields within 20%. Long term stability of neutron yield was tested at two nominal proton energies, 2.1 and 1.95 MeV over an experimental period of one year. The results show that the yield at 2.1 MeV was stable within rmse variation coefficient of 4.7% and remained consistent even when the lithium target was replaced, whereas at 1.95 MeV, the maximum fluctuations reached a factor of 10.

  15. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2013-12-01

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the 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. 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 ˜200 °C 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 dissipate electron power areal densities of >4 kW/cm2 and volume power density of ˜2 MW/cm3 at a lithium flow of ˜4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91-2.5 MeV, 1-2 mA) at SARAF.

  17. 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.

  18. Neutron energy spectra from the thick target 9Be(d,n)10B reaction

    International Nuclear Information System (INIS)

    Whittlestone, S.

    1976-12-01

    The energy spectrum of neutrons emitted when deuterons impinge on a thick beryllium target has been measured using an NE213 scintillation detector and the time-of-flight technique. Spectra were measured at angles of 0, 30, 45, 60, 90, 120 and 150 0 for deuteron energies of 1.4, 1.8, 2.3 and 2.8 MeV. Tables are presented of these angle-dependent energy spectra, the angle-integrated energy dependent yeidls, and the total neutron yield as a function of deuteron energy. (author)

  19. Preparation of thin arsenic and radioarsenic targets for neutron capture studies

    International Nuclear Information System (INIS)

    Fassbender, M.; Bach, H.; Bond, E.; Nortier, F.M.; Vieira, D.

    2009-01-01

    A simple method for the electrodeposition of elemental arsenic (As) on a metal backing from aqueous solutions has been developed. The method was successfully applied to stable As ( 75 As). Thin (2.5 mg cm -2 ) coherent, smooth layers of the metalloid on Ti foils (2.5 μm thickness) were obtained. Electrodeposits served as targets for 75 As(n,γ) 76 As neutron capture experiments at Los Alamos Neutron Science Center (LANSCE). Respective 73 As(n,γ) 74 As experiments are planned for the near future, and 73 As targets will be prepared in a similar fashion utilizing the new electrodeposition method. The preparation of an 73 As (half-life 80.3 days) plating bath solution from proton irradiated germanium has been demonstrated. Germanium target irradiation was performed at the Los Alamos Isotope Production Facility (IPF). (author)

  20. Differential neutron production cross sections and neutron yields from stopping-length targets for 113-MeV protons

    International Nuclear Information System (INIS)

    Meier, M.M.; Amian, W.B.; Clark, D.A.; Goulding, C.A.; McClelland, J.B.; Morgan, G.L.; Moss, C.E.

    1989-03-01

    We have measured differential (P,ξn) cross sections, d 2 σ/dΩdE/sub n/, from thin targets and absolute neutron yields from stopping-length targets at angles of 7.5/degree/, 30/degree/, 60/degree/, and 150/degree/, for the 113--MeV proton bombardment of elemental beryllium, carbon, aluminum, iron, and depleted uranium. Additional cross-section measurements are reported for oxygen, tungsten, and lead. We used time-of-flight techniques to identify and discriminate against backgrounds and to determine the neutron energy spectrum. Comparison of the experimental data with intranuclear-cascade evaporation-model calculations with the code HETC showed discrepancies as high as a factor of 7 in the differential cross sections. These discrepancies in the differential cross sections make it possible to identify some of the good agreement seen in the stopping-length yield comparisons as fortuitous cancellation of incorrect production estimates in different energy regimes. 13 refs., 20 figs., 4 tabs

  1. Sensitivity studies of the neutron multiplicity spectrum in the spallation of Pb targets

    International Nuclear Information System (INIS)

    Sinha, A.; Garg, S.B.; Srinivasan, M.

    1986-01-01

    The number of neutrons produced per incident proton in the spallation of Pb targets is of direct relevance to the design of accelerator breeders. The nuclear cascade initiated by high-energy protons in spallation targets is usually described by an intranuclear cascade evaporation (INCE) model. Even though this model describes various average nuclear properties of spallation targets fairly well, differential quantities such as energy spectra, angular spectra etc., are not reproduced within the limits of experimental uncertainty. One of the reasons for this is the uncertainty in the magnitude of the parameters involved in the model, notably the level density parameter Bsub(O) whose magnitude is quoted by different workers to be in the range of 8-20 MeV. The accuracy of Bsub(O) could be improved if we could experimentally determine a quantity which is much more sensitive to Bsub(O) than the average neutron yield. In this paper we discuss one such quantity, namely the neutron multiplicity spectrum (MS). We compute the MS due to the spallation of Pb targets of different sizes at proton energies of 1.5, 1.0 and 0.59 GeV using the Monte Carlo code HETC. It is noticed that for the 1.5 GeV proton case the probability P(ν) for leakage of ν neutrons for ν in the range of 60-65, changes by about 70% when Bsub(O) is varied from 8 to 20 MeV. The corresponding change in the average neutron yield is <20%. It is therefore suggested that an accurate measurement of the MS can serve as a useful tool to narrow down the range of uncertainty in the Bsub(O) parameter. (author)

  2. Neutron spectrum at 900 from 800 MeV (p,n) reactions on a Ta target

    International Nuclear Information System (INIS)

    Howe, S.D.; Lisowski, P.W.; King, N.S.P.; Russell, G.J.; Donnert, H.J.

    1979-01-01

    The neutron time-of-flight spectrum produced by a thick tantalum target bombarded by 800-MeV protons was measured at an angle of 90 0 . The data were taken at the Weapons Neutron Research facility by use of a cylindrical Ta target with a radius of 1.27 cm and a length of 15 cm. An NE-213 liquid scintillator was used to detect the neutrons over an energy range of 0.5 to 350 MeV. The neutron yield is presented and compared to a intranuclear-cascade/evaporation model prediction. 3 figures

  3. The LANSCE (Los Alamos Neutron Scattering Center) target data collection system

    International Nuclear Information System (INIS)

    Kernodle, A.K.

    1989-01-01

    The Los Alamos Neutron Scattering Center (LANSCE) Target Data Collection System is the result of an effort to provide a base of information from which to draw conclusions on the performance and operational condition of the overall LANSCE target system. During the conceptualization of the system, several goals were defined. A survey was made of both custom-made and off-the-shelf hardware and software that were capable of meeting these goals. The first stage of the system was successfully implemented for the LANSCE run cycle 52. From the operational experience gained thus far, it appears that the LANSCE Target Data Collection System will meet all of the previously defined requirements

  4. Spin filtering neutrons with a proton target dynamically polarized using photo-excited triplet states

    International Nuclear Information System (INIS)

    Haag, M.; Brandt, B. van den; Eichhorn, T.R.; Hautle, P.; Wenckebach, W.Th.

    2012-01-01

    In a test of principle a neutron spin filter has been built, which is based on dynamic nuclear polarization (DNP) using photo-excited triplet states. This DNP method has advantages over classical concepts as the requirements for cryogenic equipment and magnets are much relaxed: the spin filter is operated in a field of 0.3 T at a temperature of about 100 K and has performed reliably over periods of several weeks. The neutron beam was also used to analyze the polarization of the target employed as a spin filter. We obtained an independent measurement of the proton spin polarization of ∼0.13 in good agreement with the value determined with NMR. Moreover, the neutron beam was used to measure the proton spin polarization as a function of position in the naphthalene sample. The polarization was found to be homogeneous, even at low laser power, in contradiction to existing models describing the photo-excitation process.

  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. A target development program for beamhole spallation neutron sources in the megawatt range

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.; Atchison, F. [Rutherford Appleton Laboratory, Oxon (United Kingdom)] [and others

    1995-10-01

    Spallation sources as an alternative to fission neutron sources have been operating successfully up to 160 kW of beam power. With the next generation of these facilities aiming at the medium power range between 0.5 and 5 MW, loads on the targets will be high enough to make present experience of little relevance. With the 0.6 MW continuous facility SINQ under construction, and a 5 MW pulsed facility (ESS) under study in Europe, a research and development program is about to be started which aimes at assessing the limits of stationary and moving solid targets and the feasibility and potential benefits of flowing liquid metal targets. Apart from theoretical work and examination of existing irradiated material, including used targets from ISIS, it is intended to take advantage of the SINQ solid rod target design to improve the relevant data base by building the target in such a way that individual rods can be equipped as irradiation capsules.

  7. Spallation Neutron Source Accelerator Facility Target Safety and Non-safety Control Systems

    International Nuclear Information System (INIS)

    Battle, Ronald E.; DeVan, B.; Munro, John K. Jr.

    2006-01-01

    The Spallation Neutron Source (SNS) is a proton accelerator facility that generates neutrons for scientific researchers by spallation of neutrons from a mercury target. The SNS became operational on April 28, 2006, with first beam on target at approximately 200 W. The SNS accelerator, target, and conventional facilities controls are integrated by standardized hardware and software throughout the facility and were designed and fabricated to SNS conventions to ensure compatibility of systems with Experimental Physics Integrated Control System (EPICS). ControlLogix Programmable Logic Controllers (PLCs) interface to instruments and actuators, and EPICS performs the high-level integration of the PLCs such that all operator control can be accomplished from the Central Control room using EPICS graphical screens that pass process variables to and from the PLCs. Three active safety systems were designed to industry standards ISA S84.01 and IEEE 603 to meet the desired reliability for these safety systems. The safety systems protect facility workers and the environment from mercury vapor, mercury radiation, and proton beam radiation. The facility operators operated many of the systems prior to beam on target and developed the operating procedures. The safety and non-safety control systems were tested extensively prior to beam on target. This testing was crucial to identify wiring and software errors and failed components, the result of which was few problems during operation with beam on target. The SNS has continued beam on target since April to increase beam power, check out the scientific instruments, and continue testing the operation of facility subsystems

  8. Thermal-hydraulic and neutronic considerations for designing a lithium-cooled tokamak blanket

    International Nuclear Information System (INIS)

    Chao, J.; Mikic, B.; Todreas, N.

    1978-12-01

    A methodology for the design of lithium cooled blankets is developed. The thermal-hydraulics, neutronics and interactions between them are extensively investigated. In thermal hydraulics, two models illustrate the methodology used to obtain the acceptable ranges for a set of design parameters. The methodology can be used to identify the limiting constraints for a particular design. A complete neutronic scheme is set up for the calculations of the volumetric heating rate as a function of the distance from the first wall, the breeding ratio as a function of the amount of structural material in the blanket, and the radiation damage in terms of atom displacements and gas production rate. Different values of the volume percent of Type-316 stainless steel are assigned in four breeding zones to represent a nonuniformly distributed structural material which satisfies various thermal-hydraulic requirements. The role that the radiation damage plays in the overall design methodology is described. The product of the first wall lifetime and neutron loading is limited by the radiation damage which degrades the mechanical properties of the material

  9. Neutron emission from projectile-like and target-like fragments in the 18O+48Ti reaction at E(18O)=116 MeV

    International Nuclear Information System (INIS)

    Chambon, B.; Drain, D.; Pastor, C.; Dauchy, A.; Giorni, A.; Morand, C.

    1982-07-01

    Angular correlations between neutrons and projectile-like fragments detected near the grazing angle were analysed by assuming two incoherent neutrons sources. One source describes slower neutrons evaporated by target-like fragments in equilibrium. The faster, forward-peaked neutrons originate from a second source strongly correlated with the projectile-like fragments with regards to velocity and direction. In some cases neutron emission may even be attributed to known neutron emitter levels in excited ejectiles

  10. Target development for the SINQ high-power neutron spallation source

    International Nuclear Information System (INIS)

    Wagner, Werner

    2002-01-01

    SINQ is a 1 MW class research spallation neutron source, driven by the PSI proton accelerator system. In terms of beam power, it is, by a large margin, the most powerful spallation neutron source currently in operation worldwide. As a consequence, target load levels prevail in SINQ which are beyond the realm of existing experience. Therefore, an extensive materials irradiation program (STIP) is currently underway which will help to select the proper structural material and make dependable life time estimates accounting for the real operating conditions that prevail in the facility. In parallel, both theoretical and experimental work is going on within the MEGAPIE (MEGAwatt Pilot Experiment) project, to develop a liquid lead-bismuth spallation target for a beam power level of 1MW

  11. Lujan Center Mark-IV Target Neutronics Design Internal Review Report

    Energy Technology Data Exchange (ETDEWEB)

    Lisowski, Paul W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gallmeier, Franz [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guber, Klaus [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2018-02-26

    The 1L Target Moderator Reflector System (TMRS) at the Lujan Center will need to be replaced before the CY 2020 operating cycle. A Physics Division design team investigated options for improving the overall target performance for nuclear science research with minimal reduction in performance for materials science. This review concluded that devoting an optimized arrangement of the Lujan TMRS upper tier to nuclear science and using the lower tier for materials science can achieve those goals. This would open the opportunity for enhanced nuclear science research in an important neutron energy range for NNSA. There will be no other facility in the US that will compete in the keV energy range provided flight paths and instrumentation are developed to take advantage of the neutron flux and resolution.

  12. Incident energy and target dependence of interaction cross sections and density distribution of neutron drip-line nuclei

    International Nuclear Information System (INIS)

    Shimoura, S.

    1992-01-01

    The relation between nuclear density distribution and interaction cross section is discussed in terms of Glauber model. Based on the model, density distribution of neutron drip-line nucleus 11 Be and 11 Li is determined experimentally from incident energy dependence of interaction cross sections of 11 Be and 11 Li on light targets. The obtained distributions have long tails corresponding to neutron halos of loosely bound neutrons. (Author)

  13. Proton and neutron polarized targets for nucleon-nucleon experiments at SATURNE II

    International Nuclear Information System (INIS)

    Ball, J.; Combet, M.; Sans, J.L.; Benda, B.; Chaumette, P.; Deregel, J.; Durand, G.; Dzyubak, A.P.; Gaudron, C.; Lehar, F.; Janout, Z.; Khachaturov, B.A.

    1996-01-01

    A SATURNE polarized target has been used for nucleon-nucleon elastic scattering and transmission experiments for 15 years. The polarized proton target is a 70 cm 3 cartridge loaded with Pentanol-2. For polarized neutron target, two cartridges loaded with 6 LiD and 6 LiH are set in the refrigerator and can be quickly inserted in the beam. First experiments using 6 Li products in quasielastic pp or pn analyzing power measurements are compared with the same observables measured in a free nucleon-nucleon scattering using polarized proton targets. Angular distribution as a function of a kinematically conjugate angle and coplanarity in nucleon-nucleon scattering is shown for different targets. (author)

  14. Design study and heat transfer analysis of a neutron converter target for medical radioisotope production

    International Nuclear Information System (INIS)

    Masoud Behzad; Sang-In Bak; Seung-Woo Hong; Jong-Seo Chai; Yacine Kadi; Claudio Tenreiro; University of Talca, Talca

    2014-01-01

    A worldwide challenge in the near future will be to find a way of producing radioisotopes in sufficient quantity without relying on research reactors. The motivation for this innovative work on targets lies in the accelerator-based production of radioisotopes using a neutron converter target as in the transmutation by adiabatic resonance crossing concept. Thermal analysis of a multi-channel helium cooled device is performed with the computational fluid dynamics code CFX. Different boundary conditions are taken into account in the simulation process and many important parameters such as maximum allowable solid target temperature as well as uniform inlet velocity and outlet pressure changes in the channels are investigated. The results confirm that the cooling configuration works well; hence such a solid target could be operated safely and may be considered for a prototype target. (author)

  15. Thermal analysis of Ti drive-in target for D-D neutron generation

    International Nuclear Information System (INIS)

    Jung, N.S.; Kim, I.J.; Kim, S.J.; Choi, H.D.

    2008-01-01

    Full text: Thermal analysis was performed for a Ti drive-in target of a D-D neutron generator. Numerical calculation was the only feasible way to obtain the information of the target temperature, since it was very difficult to measure the target temperature during neutron generation due to high voltage being applied to the target. Computational fluid dynamics code CFX-5 was used in this study. In order to define the heat flux term for the thermal analysis, the current profile of the ion beam was measured. The one-dimensional, integrated current profile was measured by using a single slit and a Faraday cup. The measured current profile was transformed into the axially symmetric two-dimensional distribution function by using the Abel inversion, which had the two-dimensional Gaussian function shape. Temperature distribution in the target was calculated at the operating condition. The influence of operational parameters like the ion beam energy, current, coolant mass flow rate and coolant inlet temperature on the target temperature was investigated

  16. Investigation of flow asymmetry and instability in the liquid mercury target of the Spallation Neutron Source

    International Nuclear Information System (INIS)

    Pointer, D.; Ruggles, A.; Wendel, M.; Crye, J.

    2000-01-01

    The Spallation Neutron Source (SNS) will utilize a liquid mercury target placed in the path of a high-energy proton beam to produce neutrons for research activities. As the high-energy protons interact with the mercury target, the majority of the beam energy is converted to thermal energy. The liquid mercury must provide sufficient heat transfer to maintain the temperature of the target structure within the thermal limits of the structural materials. Therefore, the behavior of the liquid mercury flow must be characterized in sufficient detail to ensure accurate evaluation of heat transfer in the mercury target. A combination of experimental and computational methods is utilized to characterize the flow in these preliminary analyses. Preliminary studies of the liquid mercury flow in the SNS target indicate that the flow in the exit channel may exhibit multiple recirculation zones, flow asymmetries, and possibly large-scale flow instabilities. While these studies are not conclusive, they serve to focus the efforts of subsequent CFD modeling and experimental programs to better characterize the flow patterns in the SNS mercury target

  17. Fast neutron distributions from Be and C thick targets bombarded with 80 and 160 MeV deuterons

    International Nuclear Information System (INIS)

    Pauwels, N.; Laurent, H.; Clapier, F.; Brandenburg, S.; Beijers, J. P .M.; Zegers, R. G. T.; Lebreton, H.; Saint-Laurent, M.G.; Mirea, M.

    2001-01-01

    Production of fast neutron studies have come to the fore in the past few years because of the great interest for the possible applications of induced fission to produce neutron rich ion beams. In this context, the main objective of the SPIRAL II (Systeme de Production d'Ions Radioactifs Acceleres en Ligne) and PARRNe (Production d'Atomes Radioactifs Riches en Neutrons) R and D projects is the investigation of the feasibility and of the optimum parameters for a neutron rich isotope source. Special attention is dedicated to the energy and angular distributions of the neutrons obtained through deuteron break--up in different types of converters and different incident energies. Analysis and modelling of such behaviors, together with the study of the yields of neutron induced fission, can be used to optimize the productivity of the fissioning target its geometry and designing it accordingly. The present report continues our previous studies realised for 17, 20, 28 and 200 MeV deuteron energies and it is focused on deuteron incident energies of 80 and 160 MeV. In the experiment, the double differential cross section for neutron production induced by 80 and 160 MeV deuterons impinging on thick C and Be targets, in which the incident deuterons were complete stopped, have been measured. The energy of the neutrons was determined from the time--of--flight (TOF) measurement. To obtain an energy resolution of about 4% for the fastest, forward--emitted neutrons, which have approximately beam velocity, the length of the flightpath for the detectors at angles up to 30 angle was chosen to be 6 m. At backward angles, where the neutron energies are lower, a shorter flightpath was chosen. A schematic drawing of the setup is shown. A 100 mm thick Be target and a 70 mm thick C target were used. Results are exemplified with the angular and energy distributions of neutron obtained for Be target at 80 MeV. (authors)

  18. 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.

  19. Thermodynamic considerations on self-regulating characteristics of a cold neutron source with a closed thermosiphon

    International Nuclear Information System (INIS)

    Kawai, Takeshi; Utsuro, Masahiko; Ogino, Fumimaru.

    1991-01-01

    The present report describes that a cold neutron source (CNS) having a closed-thermosiphon cooling loop shows a self-regulating characteristic under thermal disturbances if the effect of the moderator transfer tube is negligible. Due to this property, the liquid level in the moderator cell is kept almost constant under thermal disturbances. The thermodynamic meaning of the self-regulating property in the idealized closed-thermosiphon and the effect of the moderator transfer tube to the self-regulation are described. (author)

  20. 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.

  1. A long-wavelength target station for the spallation neutron source

    International Nuclear Information System (INIS)

    Carpenter, J.M.; Mason, T.E.

    2005-01-01

    The Spallation Neutron Source (SNS), a major new user facility for studies of the structure and dynamics of materials, funded by the US Department of Energy (DOE), is under construction at Oak Ridge National Laboratory (ORNL). Details about the project are available in a recent paper and on the SNS Web site [MRS Bull. 28 (12) (2003) 923]. A Long-Wavelength Target Station (LWTS) [Technical Concepts for a Long-Wavelength Target Station for the Spallation Neutron Source, Argonne National Laboratory Report ANL-02/16, Oak Ridge National Laboratory Report ORNL/SNS-TM-2001/163, November 2002. See also www.pns.anl.gov/related/] will complement the High-Power Target Station (HPTS) facility of the SNS and will build upon the significant investment in the remainder of the installation by providing important new scientific opportunities. For areas of science using the optimized long-wavelength beam lines, the LWTS will at least double the overall scientific capability of the SNS and provide for up to an order of magnitude performance gain over the initial HPTS. The fully equipped SNS has the prospect to offer capabilities for neutron-scattering studies of the structure and dynamics of materials with sensitivity, resolution, dynamic range, and speed that are unparalleled in the world. Preliminary assessments of the performance of the several instruments treated in detail in the body of the paper bear out this expectation. The LWTS concept has been developed in close consultation with the scientific community through a series of workshops and conferences jointly sponsored by DOE's Office of Basic Energy Science and the National Science Foundation. We describe the principal features of the LWTS concept, and provide a preliminary summary of some neutron scattering instruments suited to exploit the unique features of the LWTS. It remains to develop concepts and designs for a full suite of instruments that exploit the capabilities of LWTS, a process that has begun in collaboration

  2. Simulation of e-{gamma}-n targets by FLUKA and measurement of neutron flux at various angles for accelerator based neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Patil, B.J., E-mail: bjp@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India); Chavan, S.T.; Pethe, S.N.; Krishnan, R. [SAMEER, IIT Powai Campus, Mumbai 400 076 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411 007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ernet.i [Department of Physics, University of Pune, Pune 411 007 (India)

    2010-10-15

    A 6 MeV Race track Microtron (an electron accelerator) based pulsed neutron source has been designed specifically for the elemental analysis of short lived activation products where the low neutron flux requirement is desirable. The bremsstrahlung radiation emitted by impinging 6 MeV electron on the e-{gamma} primary target, was made to fall on the {gamma}-n secondary target to produce neutrons. The optimisation of bremsstrahlung and neutron producing target along with their spectra were estimated using FLUKA code. The measurement of neutron flux was carried out by activation of vanadium and the measured fluxes were 1.1878 x 10{sup 5}, 0.9403 x 10{sup 5}, 0.7428 x 10{sup 5}, 0.6274 x 10{sup 5}, 0.5659 x 10{sup 5}, 0.5210 x 10{sup 5} n/cm{sup 2}/s at 0{sup o}, 30{sup o}, 60{sup o}, 90{sup o}, 115{sup o}, 140{sup o} respectively. The results indicate that the neutron flux was found to be decreased as increase in the angle and in good agreement with the FLUKA simulation.

  3. Measurement of the Neutron Component in a Shower Generated in a Lead Target by Relativistic Nuclear Beam

    International Nuclear Information System (INIS)

    Chultehm, D.; Damdinsurehn, Ts.; D'yachenko, V.M.; Ehnkhzhin, L.; Lomova, L.A.; Perelygin, V.P.; Tolstov, K.D.

    1994-01-01

    The present paper describes a method of determining the total number of neutrons generated in an extended lead target by relativistic nuclei and protons. It is shown that 101±20 neutrons per proton are produced in the target with the volume of 50x50x80 cm 3 at 3.65 GeV energy of protons. 11 refs., 14 figs., 1 tab

  4. Fast neutron forward distributions from C, Be and U thick targets bombarded by deuterons

    International Nuclear Information System (INIS)

    Menard, S.; Clapier, F.; Pauwels, N.; Proust, J.; Donzaud, C.; Guillemaud-Mueller, D.; Lhenry, I.; Mueller, A.C.; Scarpaci, J.A.; Sorlin, O.; Mirea, M.

    1999-01-01

    In principle, to produce neutron rich radioactive beams with sufficient intensities, a source of isotopes far from the valley of β--stability can be obtained through the fission of 238 U induced by fast neutrons. A very promising way to assess the feasibility of these very intense neutron beams is to break an intense 2 H beam in a dedicated converter. The main objective of SPIRAL and PARRNe R - D projects is the investigation of the optimum parameters for a neutron rich isotope source in accordance with the scheme presented above. In such conditions, the charge particle energy loss can prevent the destruction of the fission target. In the frame of these project, a special attention is dedicated to the energetic and angular distributions of the neutrons emerging from a set of converters at a series of 2 H incident energies. Deuteron beams at energies less than 30 MeV are particularly interesting because it is expected that, after the decay in the 238 U target, the neutron rich radioactive fission products are cold enough, thus avoiding the evaporation of a too large number of neutrons. For such purposes, one needs experimental angular distributions at given energies for different types of converters and to elaborate a theoretical tool in order to estimate accurately the characteristics of the secondary neutron beam. In this paper, the experimental results were obtained with 17, 20 and 28 MeV deuteron energies on Be, C and U converters using the time of flight method. These data are compared to results given by a model valid at higher energy in order to obtain pertinent simulations in a large range of incident energies. Many theoretical tools were developed to characterize the properties of the neutron beams emerging from thick targets. In this contribution the Serber's model, considered with its improvements which account for the Coulomb deflection and the mean straggling of the beam in the material, is compared to experimental data in order to verify the validity

  5. Some experimental considerations regarding ion beam simulation of neutron irradiation for mechanical property measurements

    International Nuclear Information System (INIS)

    Styris, D.L.; Jones, R.H.; Harling, O.K.; Kulcinski, G.L.; Marshall, R.P.

    1975-01-01

    A preliminary assessment of the requirements for mechanical property data related to CTR materials is given. The status of ion simulation for mechanical property measurements is described. A damage analysis and calculations for light ions are presented along with sample size, heating and cooling, and surface considerations

  6. Influence of different moderator materials on characteristics of neutron fluxes generated under irradiation of lead target with proton beams

    International Nuclear Information System (INIS)

    Sosnin, A.N.; Polanski, A.; Petrochenkov, S.A.

    2002-01-01

    Neutron fields generated in extended heavy (Z ≥ 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 (diam. 8 cm x 20 cm or diam. 8 cm x 50 cm) screened by variable thickness of polyethylene or graphite, respectively, was compared. 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

  7. 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.

  8. Study of neutron spectra in extended uranium target. New experimental data

    Directory of Open Access Journals (Sweden)

    Paraipan M.

    2017-01-01

    Full Text Available The spatial distribution of neutron fluences in the extended uranium target (“Quinta” assembly irradiated with 0.66 GeV proton, 4 AGeV deuteron and carbon beams was studied using the reactions with different threshold energy (Eth. The data sets were obtained with 59Co samples. The accumulation rates for the following isotopes: 60Co (Eth 0 MeV, 59Fe (Eth 3 MeV, 58Co (Eth 10 MeV, 57Co (Eth 20 MeV, 56Co (Eth 32 MeV, 47Sc (Eth 55 MeV, and 48V (Eth 70 MeV were measured with HPGe spectrometer. The experimental accumulation rates were compared with the predictions of the simulations with Geant4 code. Substantial difference between the reconstructed and the simulated data for the hard part of the neutron spectrum was analyzed.

  9. Intensity-Modulated Radiotherapy for Craniospinal Irradiation: Target Volume Considerations, Dose Constraints, and Competing Risks

    International Nuclear Information System (INIS)

    Parker, William; Filion, Edith; Roberge, David; Freeman, Carolyn R.

    2007-01-01

    Purpose: To report the results of an analysis of dose received to tissues and organs outside the target volume, in the setting of spinal axis irradiation for the treatment of medulloblastoma, using three treatment techniques. Methods and Materials: Treatment plans (total dose, 23.4 Gy) for a standard two-dimensional (2D) technique, a three-dimensional (3D) technique using a 3D imaging-based target volume, and an intensity-modulated radiotherapy (IMRT) technique, were compared for 3 patients in terms of dose-volume statistics for target coverage, as well as organ at risk (OAR) and overall tissue sparing. Results: Planning target volume coverage and dose homogeneity was superior for the IMRT plans for V 95% (IMRT, 100%; 3D, 96%; 2D, 98%) and V 107% (IMRT, 3%; 3D, 38%; 2D, 37%). In terms of OAR sparing, the IMRT plan was better for all organs and whole-body contour when comparing V 10Gy , V 15Gy , and V 20Gy . The 3D plan was superior for V 5Gy and below. For the heart and liver in particular, the IMRT plans provided considerable sparing in terms of V 10Gy and above. In terms of the integral dose, the IMRT plans were superior for liver (IMRT, 21.9 J; 3D, 28.6 J; 2D, 38.6 J) and heart (IMRT, 9 J; 3D, 14.1J; 2D, 19.4 J), the 3D plan for the body contour (IMRT, 349 J; 3D, 337 J; 2D, 555 J). Conclusions: Intensity-modulated radiotherapy is a valid treatment option for spinal axis irradiation. We have shown that IMRT results in sparing of organs at risk without a significant increase in integral dose

  10. Laser fusion target illumination optimization with consideration of the beam divergence

    International Nuclear Information System (INIS)

    Grzanna, J.; Schoennagel, H.

    1982-09-01

    Using a focusing system with a great focal length it is demonstrated that the radiation divergence considerably influences the illumination optimization. If the channel beam is composed of several single beams, there are two optimum illumination variants: the channel beam tangent and the single beam tangent illumination. Further, it is shown that the illumination channel distribution function can vary in the central region without any effect on the illumination uniformity. The deviation at the periphery is more critical. The most homogeneous illumination and favourable energy transfer would be obtained by low radiation divergence and optimum lateral and axial defocusing of the single beam imaging a suitable near-field intensity pattern on the target surface. It is emphasized that the estimation was made without considering the plasma parameters and the dynamic variation in time. (author)

  11. 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.

  12. The Spin Structure of the Neutron Determined Using a Polarized He-3 Target

    Energy Technology Data Exchange (ETDEWEB)

    Middleton, H

    2004-01-06

    Described is a study of the internal spin structure of the neutron performed by measuring the asymmetry in spin-dependent deep inelastic scattering of polarized electrons from nuclear polarized {sup 3}He. Stanford Linear Accelerator experiment E142's sample of 400 million scattering events collected at beam energies between 19 and 26 GeV led to the most precise measurement of a nucleon spin structure function to date. The {sup 3}He target represents a major advance in polarized target technology, using the technique of spin exchange with optically pumped rubidium vapor to produce a typical {sup 3}He nuclear polarization of 34% in a 30cm long target cell with a gas density of 2.3 x 10{sup 20} cm{sup -3}. The target polarization was measured to {+-}7% using an Adiabatic Fast Passage NMR system calibrated with the thermal equilibrium polarization of the protons in a sample of water. The relatively high polarization and target thickness were the result of the development of large volume glass target cells which had inherent nuclear spin relaxation times for the {sup 3}He gas of as long as 70 hours. A target cell production procedure is presented which focuses on special glass blowing techniques to minimize surface interactions with the {sup 3}He nuclei and careful gas purification and vacuum system procedures to reduce relaxation inducing impurities.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lhersonneau, G.; Fadil, M. [GANIL, Caen (France); Malkiewicz, T. [CSC - IT Center for Science Ltd., Espoo (Finland); Gorelov, D.; Sorri, J.; Trzaska, W.H. [University of Jyvaskyla, Department of Physics, Jyvaskyla (Finland); Jones, P.; Ngcobo, P.Z. [iThemba Laboratory for Accelerator Based Science, Western Cape (South Africa)

    2016-12-15

    The neutron yield of thick targets of carbon, natural and enriched in {sup 13}C, bombarded by deuterons of 20 and 30 MeV has been measured by the activation method. The gain with respect to a {sup 12}C target is the same as with protons beams. The yield ratio is about 1.2 only and hardly can justify the use of a {sup 13}C 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 {sup 12}C and {sup 13}C targets. (orig.)

  14. Measurements of the thermophysical properties of graphite composites for a neutron target converter

    Energy Technology Data Exchange (ETDEWEB)

    Zhmurikov, E.I. [Budker Institute of Nuclear Physics, 690090 Novosibirsk, SB RAS (Russian Federation); Savchenko, I.V.; Stankus, S.V.; Yatsuk, O.S. [Kutateladze Institute of Thermal Physics, 690090 Novosibirsk, SB RAS (Russian Federation); Tecchio, L.B., E-mail: tecchio@lnl.infn.it [Laboratori Nazionali di Legnaro-Istituto Nazionale di Fisica Nucleare, Legnaro (Italy)

    2012-05-11

    The thermo-physical characteristics of both nuclear, industrial graphite, such as MPG-6 from NIIGRAFIT or SGL composite from SGL Carbon Group, and the first synthesized graphite composite based on a carbon {sup 13}S isotope have been measured from room temperature to 1675 K by laser flash method on an LFA-427 setup from Netzsch (Germany). The results obtained are compared to the previous data of X-Ray analysis and high-resolution electron microscopy and can be used in thermal calculations of the design of a neutron converter graphite target.

  15. Measurements of the thermophysical properties of graphite composites for a neutron target converter

    International Nuclear Information System (INIS)

    Zhmurikov, E.I.; Savchenko, I.V.; Stankus, S.V.; Yatsuk, O.S.; Tecchio, L.B.

    2012-01-01

    The thermo-physical characteristics of both nuclear, industrial graphite, such as MPG-6 from NIIGRAFIT or SGL composite from SGL Carbon Group, and the first synthesized graphite composite based on a carbon 13 S isotope have been measured from room temperature to 1675 K by laser flash method on an LFA-427 setup from Netzsch (Germany). The results obtained are compared to the previous data of X-Ray analysis and high-resolution electron microscopy and can be used in thermal calculations of the design of a neutron converter graphite target.

  16. Bounds on Time Reversal Violation From Polarized Neutron Capture With Unpolarized Targets.

    Science.gov (United States)

    Davis, E D; Gould, C R; Mitchell, G E; Sharapov, E I

    2005-01-01

    We have analyzed constraints on parity-odd time-reversal noninvariant interactions derived from measurements of the energy dependence of parity-violating polarized neutron capture on unpolarized targets. As previous authors found, a perturbation in energy dependence due to a parity (P)-odd time (T)-odd interaction is present. However, the perturbation competes with T-even terms which can obscure the T-odd signature. We estimate the magnitudes of these competing terms and suggest strategies for a practicable experiment.

  17. The Precision Measurement of the Neutron Spin Structure Function Using Polarized HE-3 Target

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X

    2004-01-05

    Using a 48.6 GeV polarized electron beam scattering off a polarized {sup 3}He target at Stanford Linear Accelerator Centre (SLAC), they measured the neutron spin structure function g{sub 1}{sup n} over kinematic(x) ranging 0.014 < x <0.7 and 1 < Q{sup 2} < 17GeV{sup 2}. The measurement gave the integral result over the neutron spin structure function {integral}{sub 0.014}{sup 0.7} g{sub 1}{sup n}(x)dx = -0.036 {+-} 0.004(stat) {+-} 0.005(syst) at an average Q{sup 2} = 5GeV{sup 2}. Along with the proton results from SLAC E143 experiment (0.03 < x) and SMC experiment (0.014 < x < 0.03), they find the Bjorken sum rule appears to be largely saturated by the data integrated down to x of 0.014. However, they observe relatively large values for g{sub 1}{sup n} at low x. The result calls into question the usual methods (Regge theory) for extrapolating to x = 0 to find the full neutron integral {integral}{sub 0}{sup t} g{sub 1}{sup n}(x) dx, needed for testing the Quark-Parton Model (QMP).

  18. 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...

  19. Safeguards Considerations for the Design of a Future Fast Neutron Sodium Cooled Reactor

    International Nuclear Information System (INIS)

    Cazalet, J.; Raymond, P.; Masson, M.; Saturnin, A.

    2015-01-01

    Incorporating safeguards at an early stage of a reactor design is a way to increase the effectiveness and efficiency of safeguards measures minimizing the possibilities of misuse of the plant or nuclear material diversion. It also reduces the impact on the construction and operation cost. At the preliminary phase, the design will integrate: confinement, containment, surveillance features and non-destructive assay equipment. Taking into account these requirements will help the operator in the approval of the plant at the design phase by national and international authorities in charge of Nuclear Material accounting and safeguards. A large amount of work has been made by the GEN IV International Forum to assess the proliferation resistance of nuclear systems. The IAEA has developed guidelines on ''Safeguards by design'' describing reference requirements for future nuclear facilities. Based on these studies, this communication details implementation of safeguards in the design of a sodium cooled fast neutron reactor (SFR) currently studied in France. Specificities are the use of MOX fuel with high concentration of plutonium and the potential capacity of breeding. A great attention should be paid to avoid diversion of nuclear material contained in fresh or irradiated fuel. Scenarios of reactor misuse are analyzed. The identification of diversion pathways and requirements for nuclear material accountancy, leads to an approach of safeguards, specific to SFR: Material Balance Areas (MBA) and some key measurement points (KMP) are characterized. Specific instrumentation assay helping in the identification and/or characterization of fuel elements and the inventory of nuclear material is described. As concerns the fuel cycle, the safeguards of the reprocessing unit will be progressively increased through the development of materials monitoring and the implementation of these measures at strategic locations of buildings, thus providing real-time information

  20. Bibliography of published papers on neutron and photon emission from thick or thin target bombarded by charged particles

    International Nuclear Information System (INIS)

    Nakamura, Takashi; Furuta, Yutaka; Sato, Kazuo; Kawachi, Kiyomitsu; Hirayama, Hideo.

    1981-09-01

    Papers describing about secondary particles, especially neutrons and photons, produced by a thick or thin target are surveyed. The survey covers twelve kinds of journals mainly from 1965 to 1980, and brief descriptions are listed about type of accelerator, projectile and target used, measurements and calculations, and quantities obtained. (author)

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

    International Nuclear Information System (INIS)

    Guzek, J.; Richardson, K.; Franklyn, C.B.; Waites, A.; McMurray, W.R.; Watterson, J.I.W.; Tapper, U.A.S.

    1999-01-01

    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 μA 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

  2. Preconceptual design of a Long-Pulse Spallation Source (LPSS) at the LANSCE Facility: Target system, facility, and material handling considerations

    International Nuclear Information System (INIS)

    Sommer, W.F.

    1995-12-01

    This report provides a summary of a preconceptual design study for the proposed Long-Pulse Spallation. Source (LPSS) at the Los Alamos Neutron Science Center (LANSCE). The LPSS will use a 0.8-MW proton beam to produce neutrons from a tungsten target. This study focuses on the design of the target station and changes to the existing building that would be made to accommodate the LPSS. The LPSS will provide fifteen flight paths to neutron scattering instruments. In addition, options for generating ultracold neutrons, pions, and muons will be available. Flight-energy, forward-scattered neutrons on the downstream side of the target will also be available for autoradiography studies. A Target Test Bed (TTB) is also proposed for full-beam tests of component materials and advanced spallation neutron sources. The design allows for separation of the experiment hall from the beam line, target, and flight paths. The target and moderator systems and the systems/components to be tested in the TTB will be emplaced and removed separately by remotely operated, shielded equipment. Irradiated materials will be transported to a hot cell adjacent to the target chamber for testing by remotely operated instruments. These tests will provide information about how materials properties are affected by proton and neutron beams

  3. Study of a neutron producing target via the 7Li(p,n)7Be reaction near its energy threshold for BNCT (boron neutron capture therapy)

    International Nuclear Information System (INIS)

    Burlon, Alejandro; Kreiner, Andres J.; Debray, Mario E.; Stoliar, Pablo; Kesque, Jose M.; Naab, Fabian; Ozafran, Mabel J.; Schuff, Juan; Vazquez, Monica; Caraballo, Maria E.; Valda, Alejandro; Somacal, Hector; Davidson, Miguel; Davidson, Jorge

    2000-01-01

    In the framework of Accelerator Based BNCT (AB-BNCT) the 7 Li(p,n) 7 Be reaction near its energy threshold is one of the most promising. In this work a thick LiF target irradiated with a proton beam was studied as a neutron source. The 1.88-2.0 MeV proton beam was produced by the tandem accelerator TANDAR at CNEA's facilities in Buenos Aires. A water-filled phantom, containing a boron sample was irradiated with the resulting neutron beam. The boron neutron capture reaction produces a 0.478 MeV gamma ray in 94 % of the cases. The neutron yield was monitored by detecting this gamma ray using a germanium detector with an 'anti-Compton' shield. Moreover, the thermal neutron flux was evaluated at different depths inside the phantom using bare and Cd-covered gold foils. A maximum neutron thermal flux of 1.4 x 10 8 1/(cm 2 -s-mA) was obtained at 4.2 cm from the phantom surface. (author)

  4. Thermal-hydraulic design concept of the solid-target system of spallation neutron source

    International Nuclear Information System (INIS)

    Tanaka, F.; Hibiki, T.; Saito, Y.; Takeda, T.; Mishima, K.

    2001-01-01

    In relation to thermal-hydraulic design of the N-Arena solid-target system of the JHF project, heat transfer experiments were performed to obtain experimental data systematically on heat transfer coefficient and CHF for vertical upward and horizontal flows in a thin rectangular channel simulating a coolant channel of the proposed spallation neutron source. Thermal-hydraulic correlations which can be used for design calculations were proposed based on the obtained data. Finally tentative results of feasibility study on maximum beam power which could be attained with a solid target were presented. The result indicated that the condition for the onset of nucleate boiling is the most significant limiting factor to the maximum beam power. (author)

  5. Measured and calculated neutron yields for 100 MeV protons on thick targets of Pb and Li

    International Nuclear Information System (INIS)

    Jones, R.T.; Lone, M.A.; Okazaki, A.

    1983-01-01

    The neutron yield per proton from thick targets of lead and lithium irradiated with 100 MeV protons has been measured and calculated. The water bath method was used to measure the neutron production, and a Faraday cup for the beam current determination. Measured yields are 0.343 +- 0.021 for lead and 0.123 +- 0.007 for lithium. Corresponding yields calculated with the nucleon-meson transport code NMTC are 0.363 +- 0.002 and 0.160 +- 0.001. Measured and calculated thermal neutron distributions in the water bath are also compared

  6. 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.

  7. Survey on neutron pre-emission at the fusion of 11 Li halo nuclei with light targets

    International Nuclear Information System (INIS)

    Petrascu, M.

    1999-01-01

    The neutron halo nuclei characterized by very large matter radii, small separation energy and small internal momentum of the valence neutrons, were discovered by Tanihata and co-workers. Until now, the halo nuclei were investigated mostly by elastic, inelastic scattering and breakup processes. It was recently predicted, that due to the very large dimension of 11 Li, one may expect, that in a fusion experiment on a light target, the valence neutrons will not be absorbed together with the 9 Li core, but will be emitted in the early stage of the reaction process. The first experiment aiming to check this expectation, was performed at the RIKEN-RIPS facility. In the experimental setup, the MUSIC chamber, achieved in the frame of IFIN-HH - RIKEN cooperation, played an important role. The obtained results confirm the prediction, indicating to a novel pre-emission effect (near 40 %, for one or two neutrons). The pre-emission of neutron pairs was investigated by time-position coincidences. It is considered that the pre-emission of neutron pairs is responsible for the experimentally observed strong neutron focusing effect. An experiment aiming to a large number of n-n coincidences, based on a new neutron array detector built in the frame of IFIN-HH - RIKEN cooperation, is in preparation. A model for the pre-emission probabilities calculations has been also worked out. Good agreement with the experimental data has been obtained. (author)

  8. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. 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.

  10. Implosion physics, alternative targets design and neutron effects on inertial fusion systems

    International Nuclear Information System (INIS)

    Velarde, G.; Martinez-Val, J.M.; Perlado, J.M.

    2001-01-01

    A new radiation transport code has been coupled with an existing multimaterial fluidynamics code using Adaptive Mesh Refinement (AMR) and its testing is presented, solving ray effect and shadow problems in SN classical methods. Important advances in atomic physics, opacity calculations and NLTE calculations, participating in significant experiments (LULI/France), have been obtained. Our new 1D target simulation model allows considering the effect of inverse Compton scattering in DT x targets (x<3%) working in a catalytic regime, showing the effectiveness of such tritium-less targets. Neutron activation of all natural elements in IFE reactors for waste management and that of target debris in NIF-type facilities have been completed. Pulse activation in structural walls is presented with a new modeling. Tritium atmospheric dispersion results indicate large uncertainties in environmental responses and needs to treat the two chemical forms. We recognise recombination barriers (metastable defects) and compute first systematic high-energy displacement cascade analysis in SiC, and radiation damage pulses by atomistic models in metals. Using Molecular Dynamics we explain the experimental evidence of low-temperature amorphization by damage accumulation in SiC. (author)

  11. Testing of a Code for the Calculation of Spectra of Neutrons Produced in a Target of a Neutron Generator

    Science.gov (United States)

    Gaganov, V. V.

    2017-12-01

    The correctness of calculations performed with the SRIANG code for modeling the spectra of DT neutrons is estimated by comparing the obtained spectra to the results of calculations carried out with five different codes based on the Monte Carlo method.

  12. Measurements of neutron spectra produced from a thick tungsten target bombarded with 5 and 15 GeV protons

    CERN Document Server

    Meigo, S; Shigyo, N; Iga, K; Iwamoto, Y; Kitsuki, H; Ishibashi, K; Maehata, K; Arima, H; Nakamo, T; Numajiri, M

    2002-01-01

    For validation of calculation codes that are employed in the design of a pulse spallation neutron source and accelerator driven system, the spectrum of neutrons produced from a thick target plays an important role. However, appropriate experimental data were scarce for incident energies higher than 0.8 GeV. In this study, the spectrum from a thick tungsten target was measured. The experiment was carried out at the pi 2 beam line of the 12-GeV proton synchrotron at KEK. The tungsten target was bombarded by 0.5- and 1.5-GeV secondary protons. The spectrum of neutrons was measured by the time-of-flight technique using organic scintillators of NE213. The calculated result with NMTC/JAM and MCNP-4A is compared with the measured data. It is found that the NMTC/JAM generally gives a good agreement with experiment. The NMTC/JAM, however, gives 50% lower neutron flux in the energy region 20~80 MeV, which is consistent with the results in a previous comparison of a lead target. For the neutrons between 20 and 80 MeV, t...

  13. Schlieren diagnostics of the Los Alamos hypersonic gas target neutron generator

    International Nuclear Information System (INIS)

    Haasz, A.A.; Lever, J.H.

    1981-01-01

    The gasdynamic behaviour of a planar model of the Los Alamos geometry hypersonic gas target neutron generator (GTNG) was investigated using Schlieren flow visualization photographs, static and total pressure and spill flow measurements. The model consisted of two symmetrical expansion nozzles with 220 μm throats producing a combined flow of about Mach 4 in the GTNG channel. Stagnation pressures of 100-800 kPa were used. Two basic flow configurations, spill line closed and spill line open, were studied in order to gain insight into the complex boundary layer development near the nozzle exit planes. Both flow configurations are discussed qualitatively, making use of the pressure measurements and theoretical analysis. (orig.)

  14. Neutronic analysis for the fission Mo99 production by irradiation of leu targets in TRIGA 14 MW reactor

    International Nuclear Information System (INIS)

    Dulugeac, S. D.; Mladin, M.; Budriman, A. G.

    2013-01-01

    Molybdenum production can be a solution for the future in the utilization of the Romanian TRIGA, taking into account the international market supply needs. Generally, two different techniques are available for Mo 99 production for use in medical Tc 99 generation.The first one is based on neutron irradiation of molybdenum targets of natural isotopic composition or enriched in Mo 98 . In a second process, Mo 99 is obtained as a result of the neutron induced fission of U 235 according to U 235 (n,f) Mo 99 . The objectives of the paper are related to Mo 99 production as a result of fission. Neutron physics parameters are determined and presented, such as: thermal flux axial distribution for the critical reactor at 10 MW inside the irradiation location; reactivity introduced by three Uranium foil containers; neutron fluxes and fission rates in the Uranium foils; released and deposited power in the Uranium foils; Mo 99 activity in the Uranium foils. (authors)

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

    International Nuclear Information System (INIS)

    Smith, T

    2003-01-01

    This thesis describes a precision measurement of the neutron spin dependent structure function, g 1 n (x). The measurement was made by the E154 collaboration at SLAC using a longitudinally polarized, 48.3 GeV electron beam, and a 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 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 3 He polarization. The fraction of events which originated in the 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 3 He reference cell in place of the polarized 3 He target. The spin dependent structure function g 1 n (z) was measured in the Bjorken x range of 0.014 2 of 5 (GeV/c) 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 1 n (x) could be studied in detail at low values of the Bjorken scaling variable x. It was found that g 1 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 1 n (x) to low x. The precision of the measurement made by the E154 collaboration at SLAC puts a tighter

  16. 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

  17. A water-cooled target of a 14 MeV neutron source

    International Nuclear Information System (INIS)

    Ogawa, Masuro; Seki, Masahiro; Kawamura, Hiroshi; Sanokawa, Konomo

    1979-09-01

    For the cooling system of a stationary target for the fusion neutronics source (FNS), designed to meet the structural, thermal and hydraulic requirements, thermohydraulic experiments were made. In the heat transfer experiment, in place of an accelerator, electric-heater assemblies were used. The relation of head loss and heat transfer was obtained as a function of Reynolds number. The head loss was not large for flow rates up to 1.3 l/s. Neither vibration of the apparatus nor cavitation of water was observed even at the maximum flow rate. The heat load of 1 kW for the beam diameter of 15mm, i.e. the requirement of FNS, could be removed by 0.2 l/s water flow, with the target-surface maximum temperature kept below 200 0 C. Extrapolation of the experimental results showed that with the target system, the maximum heat load is 2.3 kW for the beam of diameter 15 mm. The value is sufficiently large compared with the heat load of FNS; with finned cooling surfaces, the heat loads up to 3.7 kW may be removed. (author)

  18. Design specification for the European Spallation Source neutron generating target element

    International Nuclear Information System (INIS)

    Aguilar, A.; Sordo, F.; Mora, T.; Mena, L.; Mancisidor, M.; Aguilar, J.; Bakedano, G.; Herranz, I.; Luna, P.; Magan, M.; Vivanco, R.; Jimenez-Villacorta, F.; Sjogreen, K.; Oden, U.; Perlado, J.M.

    2017-01-01

    The paper addresses some of the most relevant issues concerning the thermal hydraulics and radiation damage of the neutron generation target to be built at the European Spallation Source as recently approved after a critical design review. The target unit consists of a set of Tungsten blocks placed inside a wheel of 2.5 m diameter which rotates at some 0.5 Hz in order to distribute the heat generated from incoming protons which reach the target in the radial direction. The spallation material elements are composed of an array of Tungsten pieces which rest on a rotating steel support (the cassette) and are distributed in a cross-flow configuration. The thermal, mechanical and radiation effects resulting from the impact of a 2 GeV proton pulse are analysed in detail as well as an evaluation of the inventory of spallation products. The current design is found to conform to specifications and found to be robust enough to deal with several accident scenarios.

  19. Design specification for the European Spallation Source neutron generating target element

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, A. [Consorcio ESS-BILBAO. Parque Tecnológico Bizkaia. Poligono Ugaldeguren III, Pol. A, 7B, 48170 Zamudio (Spain); Sordo, F., E-mail: fernando.sordo@essbilbao.org [Consorcio ESS-BILBAO. Parque Tecnológico Bizkaia. Poligono Ugaldeguren III, Pol. A, 7B, 48170 Zamudio (Spain); Instituto de Fusión Nuclear, José Gutiérrez Abascal, 2, 28006 Madrid (Spain); Mora, T. [Consorcio ESS-BILBAO. Parque Tecnológico Bizkaia. Poligono Ugaldeguren III, Pol. A, 7B, 48170 Zamudio (Spain); Mena, L. [Consorcio ESS-BILBAO. Parque Tecnológico Bizkaia. Poligono Ugaldeguren III, Pol. A, 7B, 48170 Zamudio (Spain); Instituto de Fusión Nuclear, José Gutiérrez Abascal, 2, 28006 Madrid (Spain); Mancisidor, M.; Aguilar, J.; Bakedano, G.; Herranz, I.; Luna, P. [Consorcio ESS-BILBAO. Parque Tecnológico Bizkaia. Poligono Ugaldeguren III, Pol. A, 7B, 48170 Zamudio (Spain); Magan, M.; Vivanco, R. [Consorcio ESS-BILBAO. Parque Tecnológico Bizkaia. Poligono Ugaldeguren III, Pol. A, 7B, 48170 Zamudio (Spain); Instituto de Fusión Nuclear, José Gutiérrez Abascal, 2, 28006 Madrid (Spain); Jimenez-Villacorta, F. [Consorcio ESS-BILBAO. Parque Tecnológico Bizkaia. Poligono Ugaldeguren III, Pol. A, 7B, 48170 Zamudio (Spain); Sjogreen, K.; Oden, U. [European Spallation Source ERIC, P.O Box 176, SE-221 00 Lund (Sweden); Perlado, J.M. [Instituto de Fusión Nuclear, José Gutiérrez Abascal, 2, 28006 Madrid (Spain); and others

    2017-06-01

    The paper addresses some of the most relevant issues concerning the thermal hydraulics and radiation damage of the neutron generation target to be built at the European Spallation Source as recently approved after a critical design review. The target unit consists of a set of Tungsten blocks placed inside a wheel of 2.5 m diameter which rotates at some 0.5 Hz in order to distribute the heat generated from incoming protons which reach the target in the radial direction. The spallation material elements are composed of an array of Tungsten pieces which rest on a rotating steel support (the cassette) and are distributed in a cross-flow configuration. The thermal, mechanical and radiation effects resulting from the impact of a 2 GeV proton pulse are analysed in detail as well as an evaluation of the inventory of spallation products. The current design is found to conform to specifications and found to be robust enough to deal with several accident scenarios.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takashi; Kurosawa, Tadahiro; Nakamura, Takashi E-mail: nakamura@cyric.tohoku.ac.jp

    2002-03-21

    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 emission angle of 0-90 deg. for bombardment with heavy ions and protons in the aforementioned energy region. This method will be quite useful to estimate the neutron source term in the neutron shielding design of high energy proton and heavy ion accelerators.

  1. Neutron irradiation therapy machine

    International Nuclear Information System (INIS)

    1980-01-01

    Conventional neutron irradiation therapy machines, based on the use of cyclotrons for producing neutron beams, use a superconducting magnet for the cyclotron's magnetic field. This necessitates complex liquid He equipment and presents problems in general hospital use. If conventional magnets are used, the weight of the magnet poles considerably complicates the design of the rotating gantry. Such a therapy machine, gantry and target facilities are described in detail. The use of protons and deuterons to produce the neutron beams is compared and contrasted. (U.K.)

  2. Optimization of a neutron production target based on the 7Li (p,n)7Be reaction with the Monte Carlo Method

    International Nuclear Information System (INIS)

    Burlon, Alejandro A.; Kreiner, Andres J.; Minsky, Daniel; Valda, Alejandro A.; Somacal, Hector R.

    2003-01-01

    In order to optimize a neutron production target for accelerator-based boron neutron capture therapy (AB-BNCT) a Monte Carlo Neutron and Photon (MCNP) investigation has been performed. Neutron fields from a LiF thick target (with both a D 2 O-graphite and a Al/AlF 3 -graphite moderator/reflector assembly) were evaluated along the centerline in a head phantom. The target neutron beam was simulated from the 7 Li(p,n) 7 Be nuclear reaction for 1.89, 2.0 and 2.3 MeV protons. The results show that it is more advantageous to irradiate the target with near resonance energy protons (2.3 MeV) because of the high neutron yield at this energy. On the other hand, the Al/AlF 3 -graphite exhibits a more efficient performance than D 2 O. (author)

  3. 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.

  4. Note: Proton irradiation at kilowatt-power and neutron production from a free-surface liquid-lithium target

    Energy Technology Data Exchange (ETDEWEB)

    Halfon, S.; Feinberg, G. [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Arenshtam, A.; Kijel, D.; Weissman, L.; Aviv, O.; Berkovits, D.; Dudovitch, O.; Eisen, Y.; Eliyahu, I.; Haquin, G.; Hazenshprung, N.; Kreisel, A.; Mardor, I.; Shimel, G.; Shor, A.; Silverman, I.; Yungrais, Z. [Soreq NRC, Yavne 81800 (Israel); Paul, M., E-mail: paul@vms.huji.ac.il; Tessler, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

    2014-05-15

    The free-surface Liquid-Lithium Target, recently developed at Soreq Applied Research Accelerator Facility (SARAF), was successfully used with a 1.9 MeV, 1.2 mA (2.3 kW) continuous-wave proton beam. Neutrons (∼2 × 10{sup 10} n/s having a peak energy of ∼27 keV) from the {sup 7}Li(p,n){sup 7}Be reaction were detected with a fission-chamber detector and by gold activation targets positioned in the forward direction. The setup is being used for nuclear astrophysics experiments to study neutron-induced reactions at stellar energies and to demonstrate the feasibility of accelerator-based boron neutron capture therapy.

  5. 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.

  6. Measurement of induced radioactivity in a spallation neutron field of a mercury target for GeV-proton bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Kasugai, Y.; Takada, H.; Nakashima, H. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    2001-03-01

    An integral experiment on radioactivity induced in spallation neutron fields was carried out under the ASTE (AGS-Spallation Target Experiment) collaboration using AGS (Alternative Gradient Synchrotron) at BNL (Brookhaven National Laboratory). The spallation neutrons were produced by bombarding a mercury target with protons of 1.6, 12 and 24 GeV. The number of protons was 3 - 4 x 10{sup 13} for each irradiation. The irradiated materials were titanium, nickel, cobalt, yttrium, and bismuth, and placed on the cylindrical surface of the mercury target at the distance of 15 - 16 cm from the beam-incident-surface of the target. Disintegration rates of induced radioactivities were measured at several cooling-time ranging from hours to months. The principal nuclides contributing to the radioactivity were pointed out for each material. The experimental results for bismuth were compared with the calculations with DCAHIN-SP code. (author)

  7. EURISOL-DS Multi-MW Target Preliminary Study of the Liquid Metal Proton-to-Neutron Converter

    CERN Document Server

    Herrera-Martínez, A; CERN. Geneva. AB Department

    2006-01-01

    This technical note summarises the design calculations performed within Task #2 of the European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL-DS) [1]. A preliminary study was carried out in order to determine the optimum value of relevant parameters in the target design. Different scenarios were simulated using the Monte Carlo code FLUKA [2]. Namely, sensitivity studies were performed to assess the impact of the projectile particle energy on the neutronics and energy deposition in the spallation target. The optimal target dimensions were also studied for every case as well as the proper target material for the liquid metal proton-to-neutron converter, since mercury and lead-bismuth eutectic are reasonable options. The effect of the beam width on the power densities was also evaluated, taking into account the geometrical limitations of the facility. Finally, a comparison between protons and deuterons as primary particles was performed, acknowledging the limitations of using FLU...

  8. Measurement of induced radioactivity in a spallation neutron field of a mercury target for GeV-proton bombardment

    International Nuclear Information System (INIS)

    Kasugai, Y.; Takada, H.; Nakashima, H.

    2001-01-01

    An integral experiment on radioactivity induced in spallation neutron fields was carried out under the ASTE (AGS-Spallation Target Experiment) collaboration using AGS (Alternative Gradient Synchrotron) at BNL (Brookhaven National Laboratory). The spallation neutrons were produced by bombarding a mercury target with protons of 1.6, 12 and 24 GeV. The number of protons was 3 - 4 x 10 13 for each irradiation. The irradiated materials were titanium, nickel, cobalt, yttrium, and bismuth, and placed on the cylindrical surface of the mercury target at the distance of 15 - 16 cm from the beam-incident-surface of the target. Disintegration rates of induced radioactivities were measured at several cooling-time ranging from hours to months. The principal nuclides contributing to the radioactivity were pointed out for each material. The experimental results for bismuth were compared with the calculations with DCAHIN-SP code. (author)

  9. A critical assessment of boron target compounds for boron neutron capture therapy.

    Science.gov (United States)

    Hawthorne, M Frederick; Lee, Mark W

    2003-01-01

    Boron neutron capture therapy (BNCT) has undergone dramatic developments since its inception by Locher in 1936 and the development of nuclear energy during World War II. The ensuing Cold War spawned the entirely new field of polyhedral borane chemistry, rapid advances in nuclear reactor technology and a corresponding increase in the number to reactors potentially available for BNCT. This effort has been largely oriented toward the eradication of glioblastoma multiforme (GBM) and melanoma with reduced interest in other types of malignancies. The design and synthesis of boron-10 target compounds needed for BNCT was not channeled to those types of compounds specifically required for GBM or melanoma. Consequently, a number of potentially useful boron agents are known which have not been biologically evaluated beyond a cursory examination and only three boron-10 enriched target species are approved for human use following their Investigational New Drug classification by the US Food and Drug Administration; BSH, BPA and GB-10. All ongoing clinical trials with GBM and melanoma are necessarily conducted with one of these three species and most often with BPA. The further development of BNCT is presently stalled by the absence of strong support for advanced compound evaluation and compound discovery driven by recent advances in biology and chemistry. A rigorous demonstration of BNCT efficacy surpassing that of currently available protocols has yet to be achieved. This article discusses the past history of compound development, contemporary problems such as compound classification and those problems which impede future advances. The latter include means for biological evaluation of new (and existing) boron target candidates at all stages of their development and the large-scale synthesis of boron target species for clinical trials and beyond. The future of BNCT is bright if latitude is given to the choice of clinical disease to be treated and if a recognized study

  10. Hydrogen isotope double differential production cross sections induced by 62.7 MeV neutrons on a lead target

    International Nuclear Information System (INIS)

    Kerveno, M.; Haddad, F.; Eudes, Ph.; Kirchner, T.; Lebrun, C.; Slypen, I.; Meulders, J.P.; Le Brun, C.; Lecolley, F.R.; Lecolley, J.F.; Louvel, M.; Lefebvres, F.; Hilaire, S.; Koning, A.J.

    2002-01-01

    Double differential hydrogen isotope production cross sections have been extracted in 62.7 MeV neutron induced reactions on a lead target. The angular distribution was measured at eight angles from 20 deg. to 160 deg. allowing the extraction of angle-differential, energy differential, and total production cross sections. A first set of comparisons with several theoretical calculations is also presented

  11. 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

  12. Pneumatic sample-transfer system for use with the Lawrence Livermore National Laboratory rotating target neutron source (RTNS-I)

    International Nuclear Information System (INIS)

    Williams, R.E.

    1981-07-01

    A pneumatic sample-transfer system is needed to be able to rapidly retrieve samples irradiated with 14-MeV neutrons at the Rotating Target Neutron Source (RTNS-I). The rabbit system, already in place for many years, has been refurbished with modern system components controlled by an LSI-11 minicomputer. Samples can now be counted three seconds after an irradiation. There are many uses for this expanded 14-MeV neutron activation capability. Several fission products difficult to isolate from mixed fission fragments can be produced instead through (n,p) or (n,α) reactions with stable isotopes. Mass-separated samples of Nd, Mo, and Se, for example, can be irradiated to produce Pr, Nb, and As radionuclides sufficient for decay scheme studies. The system may also be used for multielement fast-neutron activation analysis because the neutron flux is greater than 2 x 10 11 n/cm 2 -sec. Single element analyses of Si and O are also possible. Finally, measurements of fast-neutron cross sections producing short-lived activation products can be performed with this system. A description of the rabbit system and instructions for its use are presented in this report

  13. Precise measurements of the thick target neutron yields of the {sup 7}Li(p,n) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Matysiak, W., E-mail: matysiw@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont., L8S 4K1 (Canada); Prestwich, W.V.; Byun, S.H. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)

    2011-07-01

    Thick target neutron yield of the {sup 7}Li(p,n){sup 7}Be reaction was measured in the proton energy range from 1.95 to 2.3 MeV by determining induced activity of the {sup 7}Be. A HPGe detector was used to detect the 478 keV gamma-rays emitted through {sup 7}Be decay. A series of irradiations with nominal proton energies of 1.95, 2.0, 2.1, 2.2, and 2.3 MeV were carried out. In an independent experiment, raw neutron spectra were collected by a {sup 3}He ion chamber for the same series of proton energies. From the raw neutron spectra, it was noted, that the effective proton energies were lower than the nominal by 50-58 keV. After corrections for the proton energy offsets were applied, the measured neutron yields matched the analytically calculated yields within 20%. Long term stability of neutron yield was tested at two nominal proton energies, 2.1 and 1.95 MeV over an experimental period of one year. The results show that the yield at 2.1 MeV was stable within rmse variation coefficient of 4.7% and remained consistent even when the lithium target was replaced, whereas at 1.95 MeV, the maximum fluctuations reached a factor of 10.

  14. Rationale for a spallation neutron source target system test facility at the 1-MW Long-Pulse Spallation Source

    International Nuclear Information System (INIS)

    Sommer, W.F.

    1995-12-01

    The conceptual design study for a 1-MW Long-Pulse Spallation Source at the Los Alamos Neutron Science Center has shown the feasibility of including a spallation neutron test facility at a relatively low cost. This document presents a rationale for developing such a test bed. Currently, neutron scattering facilities operate at a maximum power of 0.2 MW. Proposed new designs call for power levels as high as 10 MW, and future transmutation activities may require as much as 200 MW. A test bed will allow assessment of target neutronics; thermal hydraulics; remote handling; mechanical structure; corrosion in aqueous, non-aqueous, liquid metal, and molten salt systems; thermal shock on systems and system components; and materials for target systems. Reliable data in these areas are crucial to the safe and reliable operation of new high-power facilities. These tests will provide data useful not only to spallation neutron sources proposed or under development, but also to other projects in accelerator-driven transmutation technologies such as the production of tritium

  15. Measurement of neutron spectra generated from bombardment of 4 to 24 MeV protons on a thick 9Be target and estimation of neutron yields

    International Nuclear Information System (INIS)

    Paul, Sabyasachi; Sahoo, G. S.; Tripathy, S. P.; Sunil, C.; Bandyopadhyay, T.; Sharma, S. C.; Ramjilal,; Ninawe, N. G.; Gupta, A. K.

    2014-01-01

    A systematic study on the measurement of neutron spectra emitted from the interaction of protons of various energies with a thick beryllium target has been carried out. The measurements were carried out in the forward direction (at 0° with respect to the direction of protons) using CR-39 detectors. The doses were estimated using the in-house image analyzing program autoTRAK-n, which works on the principle of luminosity variation in and around the track boundaries. A total of six different proton energies starting from 4 MeV to 24 MeV with an energy gap of 4 MeV were chosen for the study of the neutron yields and the estimation of doses. Nearly, 92% of the recoil tracks developed after chemical etching were circular in nature, but the size distributions of the recoil tracks were not found to be linearly dependent on the projectile energy. The neutron yield and dose values were found to be increasing linearly with increasing projectile energies. The response of CR-39 detector was also investigated at different beam currents at two different proton energies. A linear increase of neutron yield with beam current was observed

  16. Calculations of the main free path on neutron emission cross-section for spallation reaction of target and fuel nuclei

    International Nuclear Information System (INIS)

    Tel, E.; Kisoglu, H. F.; Topaksu, A. K.; Aydin, A.; Kaplan, A.

    2007-01-01

    There are several new technological application fields of fast neutrons such as accelerator-driven incineration/ transmutation of the long-lived radioactive nuclear wastes (in particular transuranium nuclides) to short-lived or stable isotopes by secondary spallation neutrons produced by high-intensity, intermediate-energy, charged-particle beams, prolonged planetary space missions, shielding for particle accelerators. Especially, accelerator driven subcritical systems (ADS) can be used for fission energy production and /or nuclear waste transmutation as well as in the intermediate-energy accelerator driven neutron sources, ions and neutrons with energies beyond 20 MeV, the upper limit of exiting data files that produced for fusion and fission applications. In these systems, the neutron scattering cross sections and emission differential data are very important for reactor neutronics calculations. The transition rate calculation involves the introduction of the parameter of mean free path determines the mean free path of the nucleon in the nuclear matter. This parameter allows an increase in mean free path, with simulation of effect, which is not considered in the calculations, such as conservation of parity and angular momentum in intra nuclear transitions. In this study, we have investigated the multiple preequilibrium matrix element constant from internal transition for Uranium, Thorium, (n,xn) neutron emission spectra. The neutron-emission spectra produced by (n,xn) reactions on nuclei of some target (for spallation) have been calculated. In the calculations, we have used the geometry dependent hybrid model and the cascade exciton model including the effects of the preequilibrium. The pre-equilibrium direct effects have been examined by using full exciton model. All calculated results have been compared with the experimental data. The obtained results have been discussed and compared with the available experimental data and found agreement with each other

  17. Laser - Polarized HE-3 Target Used for a Precision Measurement of the Neutron Spin Structure

    Energy Technology Data Exchange (ETDEWEB)

    Romalis, M

    2003-11-05

    This thesis describes a precision measurement of the deep inelastic neutron spin structure function g{sub 1}{sup n}(x). The main motivation for the experiment is a test of the Bjorken sum rule. Because of smaller statistical errors and broader kinematic coverage than in previous experiments, we are able to study in detail the behavior of the spin structure function g{sub 1}{sup n}(x) for low values of the Bjorken scaling variable x. We find that it has a strongly divergent behavior, in contradiction to the naive predictions of the Regge theory. This calls into question the methods commonly used for extrapolation of g{sub 1}{sup n}(x) to x = 0. The difference between the proton and the neutron spin structure functions is less divergent at low x, so a test of the Bjorken sum rule is possible. We confirm the sum rule with an accuracy of 8%. The experiment was performed at SLAC using a 50 GeV polarized electron beam and a polarized {sup 3}He target. In this thesis the polarized target is described in detail. We used the technique of Rb optical pumping and Rb-He spin exchange to polarize the {sup 3}He. Because of a novel mechanical design our target had the smallest dilution ever achieved for a high density gas target. Since this is a precision measurement, particular efforts were made to reduce the systematic errors due to the uncertainty in the target parameters. Most important parameters were measured by more than one method. We implemented novel techniques for measuring the thickness of the glass windows of the target, the {sup 3}He density, and the polarization. In particular, one of the methods for measuring the gas density relied on the broadening of the Rb optical absorption lines by collisions with {sup 3}He atoms. The calibration of this technique resulted in the most precise measurements of the pressure broadening parameters for {sup 3}He as well as several other gases, which are described in an Appendix. The polarization of the {sup 3}He was also measured by

  18. Impact of neutron and gamma radiation on the design of NIF diagnostics and target-bay systems

    Energy Technology Data Exchange (ETDEWEB)

    Eder, D.C.; Song, P.M.; Latkowski, J.F.; Reyes, S.; O' Brien, D.W.; Lee, F.D.; Young, B.K.; Koch, J.A.; Moran, M.J.; Watts, P.W.; Kimbrough, J.R.; Ng, E.W.; Landen, O.L.; MacGowan, B.J. [Lawrence Livermore National Lab., Livermore, CA (United States)

    2006-06-15

    The design of a wide range of components in and near the target bay of the National Ignition Facility (NIF) must allow for significant radiation from neutrons and gammas. Detailed 3-dimensional Monte Carlo simulations are critical to determine neutron and gamma fluxes for all target-bay components to allow optimization of location and auxiliary shielding. Demonstration of ignition poses unique challenges because of the large range (about 3 orders of magnitude) in the yield for any given attempt at ignition. Some diagnostics will provide data independent of yield, while others will provide data for lower yields and only survive high yields with little or no damage. In addition, for a given yield there is a more than 10 orders of magnitude range in neutron and gamma fluxes depending on location in the facility. For example, sensitive components in the diagnostic mezzanines and switchyards require auxiliary shielding for high-yield shots even though they are greater than 17 meters from target chamber center (TCC) and shielded by the 2 m-thick target-bay wall. In contrast, there are components 0.2 to 2 m from TCC with little or no shielding. For these components, particular attention is being made to use low-activation material because of the extremely high neutron loading levels. Many of the components closest to target center are designed to be single use to reduce worker dose from having to refurbish highly activated components. The cryogenic target positioner is an example where activation and ease of component replacement is an important part of the design. We are developing a design process for all target-bay systems that will assure reliable operation for the full range of planned yields. (authors)

  19. Impact of neutron and gamma radiation on the design of NIF diagnostics and target-bay systems

    Science.gov (United States)

    Eder, D. C.; Song, P. M.; Latkowski, J. F.; Reyes, S.; O'Brien, D. W.; Lee, F. D.; Young, B. K.; Koch, J. A.; Moran, M. J.; Watts, P. W.; Kimbrough, J. R.; Ng, E. W.; Landen, O. L.; MacGowan, B. J.

    2006-06-01

    The design of a wide range of components in and near the target bay of the National Ignition Facility (NIF) must allow for significant radiation from neutrons and gammas. Detailed 3D Monte Carlo simulations are critical to determine neutron and gamma fluxes for all target-bay components to allow optimization of location and auxiliary shielding. Demonstration of ignition poses unique challenges because of the large range (˜ 3 orders of magnitude) in the yield for any given attempt at ignition. Some diagnostics will provide data independent of yield, while others will provide data for lower yields and only survive high yields with little or no damage. In addition, for a given yield there is a more than 10 orders of magnitude range in neutron and gamma fluxes depending on location in the facility. For example, sensitive components in the diagnostic mezzanines and switchyards require auxiliary shielding for high-yield shots even though they are greater than 17 meters from target chamber center (TCC) and shielded by the 2 m-thick target-bay wall. In contrast, there are components 0.2 to 2 m from TCC with little or no shielding. For these components, particular attention is being made to use low-activation material because of the extremely high neutron loading levels. Many of the components closest to target center are designed to be single use to reduce worker dose from having to refurbish highly activated components. The cryogenic target positioner is an example where activation and ease of component replacement is an important part of the design. We are developing a design process for all target-bay systems that will assure reliable operation for the full range of planned yields.

  20. Experimental study on neutronics in bombardment of thick targets by high energy proton beams for accelerator-driven sub-critical system

    CERN Document Server

    Guo Shi Lun; Shi Yong Qian; Shen Qing Biao; Wan Jun Sheng; Brandt, R; Vater, P; Kulakov, B A; Krivopustov, M I; Sosnin, A N

    2002-01-01

    The experimental study on neutronics in the target region of accelerator-driven sub-critical system is carried out by using the high energy accelerator in Joint Institute for Nuclear Research, Dubna, Russia. The experiments with targets U(Pb), Pb and Hg bombarded by 0.533, 1.0, 3.7 and 7.4 GeV proton beams show that the neutron yield ratio of U(Pb) to Hg and Pb to Hg targets is (2.10 +- 0.10) and (1.76 +- 0.33), respectively. Hg target is disadvantageous to U(Pb) and Pb targets to get more neutrons. Neutron yield drops along 20 cm thick targets as the thickness penetrated by protons increases. The lower the energy of protons, the steeper the neutron yield drops. In order to get more uniform field of neutrons in the targets, the energy of protons from accelerators should not be lower than 1 GeV. The spectra of secondary neutrons produced by different energies of protons are similar, but the proportion of neutrons with higher energy gradually increases as the proton energy increases

  1. Assessing the Response to Targeted Therapies in Renal Cell Carcinoma: Technical Insights and Practical Considerations

    NARCIS (Netherlands)

    Bex, A.; Fournier, L.; Lassau, N.; Mulders, P.F.A.; Nathan, P.; Oyen, W.J.G.; Powles, T.

    2014-01-01

    CONTEXT: The introduction of targeted agents for the treatment of renal cell carcinoma (RCC) has resulted in new challenges for assessing response to therapy, and conventional response criteria using computed tomography (CT) are limited. It is widely recognised that targeted therapies may lead to

  2. Angular measurement of the energy distribution of neutrons from the thick target 7Li(p,n)7Be source

    International Nuclear Information System (INIS)

    Rose, A.

    1981-11-01

    The energy spectrum of neutrons emitted from a thick lithium target bombarded by protons has been measured as a function of neutron angle of emission. The measurements were done at proton energies up to 2.8 MeV and at 30 deg. intervals in the range 0 to 120 deg. using proportional detectors with gas fillings of hydrogen and methane. A review is given of papers published on the 7 Li(p,n) 7 Be reactions at 0 deg.; where applicable, comparisons are made with the present results

  3. Photo-neutron yields from thin and thick targets irradiated by 2.0 GeV electrons

    International Nuclear Information System (INIS)

    Hee-Seock, Lee; Syuichi, Ban; Toshiya, Sanami; Kazutoshi, Takahashi; Tatsuhiko, Sato; Kazuo, Shin

    2005-01-01

    The photo-neutron yields from thin and thick targets irradiated by high energy electrons were studied. The photo-neutron spectra at 90 deg C relative to the incident 2.0 GeV electrons were measured by the pulsed beam time-of-flight technique using the Pilot-U plastic scintillator and the NE213 liquid scintillator with 2 inches in length and 2 inches in diameter. Targets, from low-Z element (carbon) to high-Z element (bismuth) and with thin (0.5 Xo) and thick (10 Xo) thickness, were used in this study. The differential photo-neutron yields between 2 MeV (mainly 8 MeV) and 400 MeV were obtained. The systematics was studied to make empirical yield terms for shielding application. Recently, the study of the angular distributed yields was conducted at two other observing angles, 48 deg C and 140 deg C. The photo-neutron yields between 8 MeV and 250 MeV were obtained for thick targets. The experimental data were compared with results calculated using the EGS4+PICA3 or the MCNPX 2.5d code. (authors)

  4. Tracking considerations for fixed target B experiments at SSC and LHC

    International Nuclear Information System (INIS)

    McManus, A.P.; Conetti, S.; Corti, G.; Cox, B.; Dukes, E.C.; Lawry, T.; Nelson, K.; Tzamouranis, I.

    1993-01-01

    Fixed target beauty (B) experiments proposed at the SSC or LHC come in two basic types. Extracted beam experiments use a bent crystal of silicon or some other method to extract a beam of protons parasitically from the circulating beam as the collider experiments are taking data. The two chief extracted beam experiments are the LHB collaboration at the LHC and the SFT collaboration at the SSC. The second type of fixed target experiment places the detector around the circulating beam using a gas jet or thin wire(s) as a target. The (GAJET) experiment proposed at CERN for LHC and the Hera-B experiment at DESY are of this type

  5. 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)

  6. Measurements of neutron spectra produced from a thick iron target bombarded with 1.5 GeV protons

    International Nuclear Information System (INIS)

    Meigo, Shin-ichiro; Takada, Hiroshi

    2001-01-01

    For validation of calculation codes which are employed in the design of accelerator facilities, spectra of neutrons produced from a thick iron target bombarded with 1.5-GeV protons were measured. The calculated results with NMTC/JAM were compared with the present experimental results. It is found the NMTC/JAM generally shows in good agreement with experiment. Furthermore, the calculation gives good agreement with the experiment for the energy region 20-80 MeV, whereas the NMTC/JAM gives 50% of the experimental data for the heavy nuclide target such as lead and tungsten target. (author)

  7. 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.

  8. Catching moving targets: cancer stem cell hierarchies, therapy-resistance & considerations for clinical intervention.

    LENUS (Irish Health Repository)

    Gasch, Claudia

    2017-01-01

    It is widely believed that targeting the tumour-initiating cancer stem cell (CSC) component of malignancy has great therapeutic potential, particularly in therapy-resistant disease. However, despite concerted efforts, CSC-targeting strategies have not been efficiently translated to the clinic. This is partly due to our incomplete understanding of the mechanisms underlying CSC therapy-resistance. In particular, the relationship between therapy-resistance and the organisation of CSCs as Stem-Progenitor-Differentiated cell hierarchies has not been widely studied. In this review we argue that modern clinical strategies should appreciate that the CSC hierarchy is a dynamic target that contains sensitive and resistant components and expresses a collection of therapy-resisting mechanisms. We propose that the CSC hierarchy at primary presentation changes in response to clinical intervention, resulting in a recurrent malignancy that should be targeted differently. As such, addressing the hierarchical organisation of CSCs into our bench-side theory should expedite translation of CSC-targeting to bed-side practice. In conclusion, we discuss strategies through which we can catch these moving clinical targets to specifically compromise therapy-resistant disease.

  9. Monte Carlo model for a thick target T(D,n)4 He neutron source

    International Nuclear Information System (INIS)

    Webster, W.M.

    1976-01-01

    A brief description is given of a calculational model developed to simulate a T(D,n) 4 He neutron source which is anisotropic in energy and intensity. The model also provides a means for including the time dependency of the neutron source. Although the model has been applied specifically to the Lawrence Livermore Laboratory ICT accelerator, the technique is general and can be applied to any similar neutron source

  10. Solubility of helium in mercury for bubbling technology of the spallation neutron mercury target

    International Nuclear Information System (INIS)

    Hasegawa, S.; Naoe, T.; Futakawa, M.

    2010-01-01

    The pitting damage of mercury target container that originates in the pressure wave excited by the proton beam incidence becomes a large problem to reach the high-power neutron source in JSNS and SNS. The lifetime of mercury container is decreased remarkably by the pitting damage. As one of solutions, the pressure wave is mitigated by injecting the helium micro bubbles in mercury. In order to inject the helium micro bubbles into mercury, it is important to understand the characteristic of micro bubbles in mercury. The solubility of mercury-helium system is a key factor to decide bubbling conditions, because the disappearance behavior, i.e. the lifetime of micro bubbles, depends on the solubility. In addition, the bubble generation method is affected by it. Moreover, the experimental data related to the solubility of helium in mercury hardly exist. In this work, the solubility was obtained experimentally by measuring precisely the pressure drop of the gas that is facing to mercury surface. The pressure drop was attributed to the helium dissolution into mercury. Based on the measured solubility, the lifetime of micro bubbles and the method of the bubble generation is estimated using the solubility data.

  11. Neutronic and thermal hydraulic analyses of LEU targets irradiated in a research reactor for Molybdenum-99 production

    International Nuclear Information System (INIS)

    Jo, Daeseong; Lee, Kyung-Hoon; Kim, Hong-Chul; Chae, Heetaek

    2014-01-01

    Highlights: • Neutronic and thermal hydraulic analyses of irradiated fuel plates for Molybdenum-99. • Heat production during and after irradiation was evaluated using MCNP and ORIGEN-APR. • Cooling capacities under various cooling conditions were evaluated using TMAP. • Natural convective cooling was adequate for the decay power after 0.03 h from withdrawal. • Maximum temperature of the target decayed for 24 h does not exceed the blistering threshold. - Abstract: Neutronic and thermal hydraulic analyses of irradiated fuel plates for Molybdenum-99 production in a research reactor were performed to investigate (1) the heat production during irradiation, (2) decay heat after irradiation, and (3) cooling capacities under various cooling conditions. The heat production on the target plates irradiated in the core was evaluated using the MCNP code. The decay heat after irradiation was evaluated using the ORIGEN-APR code, and compared against ANSI/ANS-5.1-1979. The cooling capacities of forced convective cooling during irradiation and natural convective cooling after irradiation were estimated using the TMAP code. An equilibrium core with different core statuses i.e., BOC, MOC, and EOC was used to evaluate power released from the targets and the axial power distribution. Based on the neutronic calculations, thermal margins i.e., the maximum wall temperature, minimum ONB temperature margin, and minimum CHF ratio were estimated, and the cooling strategy of the fission Mo targets was discussed. The targets were cooled by forced convective cooling during irradiation, and cooled by natural convective cooling after irradiation. For a further production process, the targets transported to a hot cell were exposed to the air, and cooled by natural convection cooling in air. As a result, the maximum wall temperature remained below the ONB temperature while the targets were under water, and the maximum wall temperature remained under the blistering limit while the targets

  12. 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...

  13. Conceptual design of the handling and storage system of the spent target vessel for neutron scattering facility 2

    International Nuclear Information System (INIS)

    Adachi, Junichi; Kaminaga, Masanori; Sasaki, Shinobu; Haga, Katsuhiro; Aso, Tomokazu; Kinoshita, Hidetaka; Hino, Ryutaro

    2002-01-01

    In designing the neutron scattering facility, a spent target vessel should be replaced with remote handling devices in order to protect radioactive exposure, since it would be highly activated through the high energy neutron irradiation caused by the spallation reaction between mercury of the target material and the MW-class proton beam. In the storage of the spent target vessel, it is necessary to consider decay heat of the target vessel and mercury contamination caused by vaporization of the residual mercury in the vessel. A conceptual design has been carried out to establish basic concept and to clarify its specification of main equipments on handling and storage systems for the spent target vessel. This report presents the basic concept and a system plot plan based on latest design works of remote handling devices such as a spent target vessel storage cask and a target vessel exchange trolley, which aim at reasonability and simplification. In addition, storage systems for the spent moderator vessel, the spent proton beam window and the spent reflector vessel are also investigated based on the plot plan. (author)

  14. Nuclear-physical investigations with oriented nuclei and polarized neutrons

    International Nuclear Information System (INIS)

    Alfimenkov, V.P.; Pikel'ner, L.B.; Sharapov, Eh.I.

    1980-01-01

    Several experiments with oriented nuclei and polarized neutrons are considered, as well as some methods of polarization of neutrons and nuclei. Experiments on the study of spin dependence of neutron cross sections for fissionable and nonfissionable nuclei interaction of polarized neutrons with polarized nuclei as well as measurement of magnetic momenta of compound-states of rare-earth nuclei. Described are some investigations with thermal neutrons: study on spin dependence of neutron scattering length with nuclei and gamma radiation of neutron radiation capture. Difficulties of production of high-intensive polarized neutron beams and construction of oriented targets are noted. Neutron polarization by transmission of them through a polarized proton target is the most universal method (out of existing methods) in the energy range under consideration [ru

  15. A Gamma Polarimeter for Neutron Polarization Measurement in a Liquid Deuterium Target for Parity Violation in Polarized Neutron Capture on Deuterium.

    Science.gov (United States)

    Komives, A; Sint, A K; Bowers, M; Snow, M

    2005-01-01

    A measurement of the parity-violating gamma asymmetry in n-D capture would yield information on N-N parity violation independent of the n-p system. Since cold neutrons will depolarize in a liquid deuterium target in which the scattering cross section is much larger than the absorption cross section, it will be necessary to quantify the loss of polarization before capture. One way to do this is to use the large circular polarization of the gamma from n-D capture and analyze the circular polarization of the gamma in a gamma polarimeter. We describe the design of this polarimeter.

  16. 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…

  17. Study on the 21 MeV neutron flux characteristics obtained in the 3H(d,n)4He reaction using of gas target

    International Nuclear Information System (INIS)

    Lovchikova, G.N.; Polyakov, A.V.; Sal'nikov, O.A.; Simakov, S.P.; Sukhikh, S.Eh.; Trufanov, A.M.

    1983-01-01

    The possibility to use gas tritium target as neutron source with the energy 2 MeV for nuclear-physical studies has been considered. Characteristics of neutron flux crested in the reaction 3 H(d, n) 4 He to obtain neutrons are investigated. The study of inelastic scattering processes at the energies permits to expand the experiments conducted up to the present day on the study of spectra of inelastically scattered neutrons in a lower energy region and it is of interest for the clarification of appearance mechanism of high-energy neutrons in the spectra. Characteristics of neutron flux as a result of the reaction 3 (α, n) 4 He at the energy of falling deuterons Esub(d)=5.54 MeV are investigated. Measurements of spectra of scattered neutrons on carbon-12 at the angles 30, 45, 60, 90, 120, 150 degrees are made. Differential cross sections of elastic scattering are obtained

  18. Overview of the national spallation neutron source with emphasis on the target station

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Barnes, J.N.; Charlton, L.A.

    1997-01-01

    The technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the National Spallation Neutron Source (NSNS), are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis and the planned hardware research and development program are also described

  19. 25-ps neutron detector for measuring ICF-target burn history

    International Nuclear Information System (INIS)

    Lerche, R.A.; Phillion, D.W.; Tietbohl, G.L.

    1994-01-01

    We have developed a fast, sensitive neutron detector for recording the fusion reaction-rate history of inertial-confinement fusion (ICF) experiments. The detector is based on the fast rise-time of a commercial plastic scintillator (BC-422) and has a response 8 and 2 x 10 13 neutrons

  20. 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.

  1. Developing plan and pre-conceptual design of target system for JAERI`s high intensity neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Hino, Ryutaro; Kaminaga, Masanori; Haga, Katsuhiro; Ishikura, Syuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakamura, Fumito; Uchida, Shoji

    1997-11-01

    This paper presents an outline of developing plan of a target system and topics obtained by a pre-conceptual design, which aims to establish a technology base of the target system and to make clear a system concept. In the plan, two types of target - solid and mercury targets - are to be developed for a neutron scattering facility. Information obtained through the development shall be applied to designs of an irradiation and a transmutation facilities. Through the pre-conceptual design, system arrangement, scale etc. were made clear: total weight will be 12000 ton, and 26 beam lines with beam shutters will be equipped for 4 moderators. Engineering problems were also made clear through the design; high flux heat removal, dynamic stress caused by thermal shock and pressure wave, loop technology for the mercury target and a slurry moderator consisting of methane pellets and liquefied hydrogen. We are now constructing new test apparatuses and arranging computer codes for solving these problems. (author)

  2. Considerations about projectile and target X-rays induced during heavy ion bombardment

    Science.gov (United States)

    Fernandes, F.; Bauer, D. V.; Duarte, A.; Ferrari, T. M.; Niekraszewicz, L. A. B.; Amaral, L.; Dias, J. F.

    2018-02-01

    In this work we present some results concerning the X-rays emitted by heavy ions during target bombardment. In this case, Cl4+ and Cl5+ ions with energies from 4 MeV to 10 MeV were employed to irradiate vitreous carbon planchets. Moreover, total X-ray production cross sections of titanium X-rays induced by chlorine ions were obtained as well for the same energy range. Only inner shell transitions were considered in the present work. The titanium target consisted of a thin film deposited over vitreous carbon planchets. The results indicate that the projectile X-ray yields increase as a function of the bombarding energy for the present energy range. Effects due to projectile charge state appears to be of minor importance at these low ion velocities. It is shown that a simple exponential function can represent the continuum background of such complex spectra. The chlorine transition rates Kβ/Kα obtained from chlorine acting as a projectile interacting with a carbon target are about half the value when compared to the chlorine Kβ/Kα ratios obtained when a LiCl target is bombarded with C+ and C3+ ions with energies from 2 MeV to 6 MeV. As far as the total X-ray production cross sections of Ti induced by chlorine ions are concerned, the ECPSSR theory underestimates the Ti total X-rays production cross sections by several orders of magnitude. The role of electron capture and possible mechanisms responsible for these effects are discussed.

  3. Assessing the response to targeted therapies in renal cell carcinoma: technical insights and practical considerations.

    Science.gov (United States)

    Bex, Axel; Fournier, Laure; Lassau, Nathalie; Mulders, Peter; Nathan, Paul; Oyen, Wim J G; Powles, Thomas

    2014-04-01

    The introduction of targeted agents for the treatment of renal cell carcinoma (RCC) has resulted in new challenges for assessing response to therapy, and conventional response criteria using computed tomography (CT) are limited. It is widely recognised that targeted therapies may lead to significant necrosis without significant reduction in tumour size. In addition, the vascular effects of antiangiogenic therapy may occur long before there is any reduction in tumour size. To perform a systematic review of conventional and novel imaging methods for the assessment of response to targeted agents in RCC and to discuss their use from a clinical perspective. Relevant databases covering the period January 2006 to April 2013 were searched for studies reporting on the use of anatomic and functional imaging techniques to predict response to targeted therapy in RCC. Inclusion criteria were randomised trials, nonrandomised controlled studies, retrospective case series, and cohort studies. Reviews, animal and preclinical studies, case reports, and commentaries were excluded. A narrative synthesis of the evidence is presented. A total of 331 abstracts and 76 full-text articles were assessed; 34 studies met the inclusion criteria. Current methods of response assessment in RCC include anatomic methods--based on various criteria including Choi, size and attenuation CT, and morphology, attenuation, size, and structure--and functional techniques including dynamic contrast-enhanced (DCE) CT, DCE-magnetic resonance imaging, DCE-ultrasonography, positron emission tomography, and approaches utilising radiolabelled monoclonal antibodies. Functional imaging techniques are promising surrogate biomarkers of response in RCC and may be more appropriate than anatomic CT-based methods. By enabling quantification of tumour vascularisation, functional techniques can directly and rapidly detect the biologic effects of antiangiogenic therapies compared with the indirect detection of belated effects

  4. On the use of lead/tin alloys as target material for the production of spallation neutrons

    International Nuclear Information System (INIS)

    Atchison, F.; Baumann, P.; Brys, T.; Daum, M.; Egorov, A.; Fierlinger, P.; Fuchs, P.; Henneck, R.; Joray, St.; Keil, R.; Kirch, K.; Krutova, R.; Kuehne, G.; Lebedev, V.T.; Obermeier, H.; Orlova, D.N.; Perret, Ch.; Pichlmaier, A.; Richard, Ph.; Serebrov, A.; Thies, S.

    2005-01-01

    We have examined the suitability of lead (Pb)/tin (Sn) alloys with atomic ratios between 4:1 and 12:1 for use as a spallation target material for the PSI spallation ultracold neutron source. The measured corrosion rate with distilled water, R c -5 cm/year, is more than a factor of 80, less than for normal Pb; this corrosion rate is satisfactory. Microscopic investigations of the surface after the exposure to water revealed no visual changes. Small angle neutron scattering showed that the alloy is mechanically stable under thermal cycling. An experimental simulation of a water-cooled spallation neutron target made of Pb/Sn pebbles with a filling factor of 60% was investigated; the pulsed proton beam was simulated using hot and cold water in the target 'cooling' circuit. With realistic operational parameters for the cooling circuit, serious deformation of the PbSn pebbles occurred which finally blocked the cooling circuit. The Pb/Sn alloys solve the corrosion problem but its mechanical properties are inadequate leading to too short a lifetime to be practical in the PSI spallation source

  5. The advanced neutron source

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1994-01-01

    The Advanced Neutron Source (ANS), slated for construction start in 1994, will be a multipurpose neutron research laboratory serving academic and industrial users in chemistry, biology, condensed matter physics, nuclear and fundamental physics, materials science and engineering, and many other fields. It will be centered on the world's highest flux neutron beam reactor, operating at 330 MW, with careful design integration between the neutron source and the experiment systems. Many instruments will be situated in low backgrounds at distances up to 80 m from the reactor, using neutron guides with tailored neutron optical coatings for beam transport. Apart from the many stations for neutron scattering research, specialized stations will also be provided for isotope separation on-line, experiments with liquid hydrogen targets, neutron optical techniques such as interferometry, activation analysis, depth profiling, and positron production. Careful consideration has been given to providing a good research environment for visiting scientists, including easy access to the experimental areas, while maintaining a highly secure nuclear facility. This paper will describe the reactor and experimental facilities and give some examples of the types of research for which ANS has been designed

  6. Practical considerations in emergency management of bleeding in the setting of target-specific oral anticoagulants.

    Science.gov (United States)

    Miller, Michael P; Trujillo, Toby C; Nordenholz, Kristen E

    2014-04-01

    The recent arrival of the target-specific oral anticoagulants (TSOACs) offers potential advantages in the field of anticoagulation. However, there are no rapid and accurate and routinely available laboratory assays to evaluate their contribution to clinical bleeding. With the expanding clinical indications for the TSOACs, and the arrival of newer reversal agents on the market, the emergency clinician will need to be familiar with drug specifics as well as methods for anticoagulation reversal. This review offers a summary of the literature and some practical strategies for the approach to the patient taking TSOACs and the management of bleeding in these cases. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Advances in implosion physics, alternative targets design, and neutron effects on heavy ion fusion reactors

    Science.gov (United States)

    Velarde, G.; Perlado, J. M.; Alonso, E.; Alonso, M.; Domínguez, E.; Rubiano, J. G.; Gil, J. M.; Gómez del Rio, J.; Lodi, D.; Malerba, L.; Marian, J.; Martel, P.; Martínez-Val, J. M.; Mínguez, E.; Piera, M.; Ogando, F.; Reyes, S.; Salvador, M.; Sanz, J.; Sauvan, P.; Velarde, M.; Velarde, P.

    2001-05-01

    The coupling of a new radiation transport (RT) solver with an existing multimaterial fluid dynamics code (ARWEN) using Adaptive Mesh Refinement named DAFNE, has been completed. In addition, improvements were made to ARWEN in order to work properly with the RT code, and to make it user-friendlier, including new treatment of Equations of State, and graphical tools for visualization. The evaluation of the code has been performed, comparing it with other existing RT codes (including the one used in DAFNE, but in the single-grid version). These comparisons consist in problems with real input parameters (mainly opacities and geometry parameters). Important advances in Atomic Physics, Opacity calculations and NLTE atomic physics calculations, with participation in significant experiments in this area, have been obtained. Early published calculations showed that a DT x fuel with a small tritium initial content ( x<3%) could work in a catalytic regime in Inertial Fusion Targets, at very high burning temperatures (≫100 keV). Otherwise, the cross-section of DT remains much higher than that of DD and no internal breeding of tritium can take place. Improvements in the calculation model allow to properly simulate the effect of inverse Compton scattering which tends to lower Te and to enhance radiation losses, reducing the plasma temperature, Ti. The neutron activation of all natural elements in First Structural Wall (FSW) component of an Inertial Fusion Energy (IFE) reactor for waste management, and the analysis of activation of target debris in NIF-type facilities has been completed. Using an original efficient modeling for pulse activation, the FSW behavior in inertial fusion has been studied. A radiological dose library coupled to the ACAB code is being generated for assessing impact of environmental releases, and atmospheric dispersion analysis from HIF reactors indicate the uncertainty in tritium release parameters. The first recognition of recombination barriers in Si

  8. Advances in implosion physics, alternative targets design, and neutron effects on heavy ion fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Velarde, G.; Perlado, J.M. E-mail: mperlado@denim.upm.es; Alonso, E.; Alonso, M.; Dominguez, E.; Rubiano, J.G.; Gil, J.M.; Gomez del Rio, J.; Lodi, D.; Malerba, L.; Marian, J.; Martel, P.; Martinez-Val, J.M.; Minguez, E.; Piera, M.; Ogando, F.; Reyes, S.; Salvador, M.; Sanz, J.; Sauvan, P.; Velarde, M.; Velarde, P

    2001-05-21

    The coupling of a new radiation transport (RT) solver with an existing multimaterial fluid dynamics code (ARWEN) using Adaptive Mesh Refinement named DAFNE, has been completed. In addition, improvements were made to ARWEN in order to work properly with the RT code, and to make it user-friendlier, including new treatment of Equations of State, and graphical tools for visualization. The evaluation of the code has been performed, comparing it with other existing RT codes (including the one used in DAFNE, but in the single-grid version). These comparisons consist in problems with real input parameters (mainly opacities and geometry parameters). Important advances in Atomic Physics, Opacity calculations and NLTE atomic physics calculations, with participation in significant experiments in this area, have been obtained. Early published calculations showed that a DT{sub x} fuel with a small tritium initial content (x<3%) could work in a catalytic regime in Inertial Fusion Targets, at very high burning temperatures ({>=}100 keV). Otherwise, the cross-section of DT remains much higher than that of DD and no internal breeding of tritium can take place. Improvements in the calculation model allow to properly simulate the effect of inverse Compton scattering which tends to lower T{sub e} and to enhance radiation losses, reducing the plasma temperature, T{sub i}. The neutron activation of all natural elements in First Structural Wall (FSW) component of an Inertial Fusion Energy (IFE) reactor for waste management, and the analysis of activation of target debris in NIF-type facilities has been completed. Using an original efficient modeling for pulse activation, the FSW behavior in inertial fusion has been studied. A radiological dose library coupled to the ACAB code is being generated for assessing impact of environmental releases, and atmospheric dispersion analysis from HIF reactors indicate the uncertainty in tritium release parameters. The first recognition of recombination

  9. 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.

  10. 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

  11. Design of a TOF-SANS instrument for the proposed long wavelength target station at the spallation neutron source

    International Nuclear Information System (INIS)

    Thiyagarajan, P.; Littrell, K.; Seeger, P.A.

    2001-01-01

    We have designed a versatile high-throughput SANS instrument [Broad Range Intense Multipurpose SANS (BRIMS)] for the proposed Long Wavelength Target Station at the SNS by using acceptance diagrams and the Los Alamos NISP Monte Carlo simulation package. This instrument has been fully optimized to take advantage of the 10 Hz source frequency (broad wavelength bandwidth) and the cold neutron spectrum from a tall coupled solid methane moderator (12 cm x 20 cm). BRIMS has been designed to produce data in a Q range spanning from 0.0025 to 0.7 A -1 in a single measurement by simultaneously using neutrons with wavelengths ranging from 1 to 14.5 A in a time of flight mode. A supermirror guide and bender assembly is employed to separate and redirect the useful portion of the neutron spectrum with λ>1 A, by 2.3deg away from the direct beam containing high energy neutrons and γ rays. The effects of various collimation choices on count rate, resolution and Q min have been characterized using spherical particle and delta function scatterers. The overall performance of BRIMS has been compared with that of the best existing reactor-based SANS instrument D22 at ILL. (author)

  12. Neutron production by 0.8 and 1.5 GeV protons on Fe and Pb targets at the most-forward region

    International Nuclear Information System (INIS)

    Satoh, Daiki; Shigyo, Nobuhiro; Ishibashi, Kenji

    2003-01-01

    Neutron-production double-differential cross-sections for 0.8 and 1.5 GeV protons incident on Fe and Pb targets were measured at the most-forward region. Neutrons were measured by the time-of-flight (TOF) method. An NE213 liquid organic scintillator was set at 0-degree as neutron detector. Neutron detection efficiencies are calculated by a Monte Carlo simulation code SCINFUL-QMD. Experimental data were compared with other experimental data and the results of calculation codes based on Intranuclear-Cascade-Evaporation (INC/E) and Quantum Molecular Dynamics (QMD) models. Disagreement with the codes is discussed. (author)

  13. 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.

  14. 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.

  15. Neutrons production during the interaction of monoenergetic electrons with a thin tungsten target

    International Nuclear Information System (INIS)

    Soto B, T. G.; Medina C, D.; Baltazar R, A.; Vega C, H. R.

    2016-10-01

    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)

  16. High flux, beamed neutron sources employing deuteron-rich ion beams from D2O-ice layered targets

    Science.gov (United States)

    Alejo, A.; Krygier, A. G.; Ahmed, H.; Morrison, J. T.; Clarke, R. J.; Fuchs, J.; Green, A.; Green, J. S.; Jung, D.; Kleinschmidt, A.; Najmudin, Z.; Nakamura, H.; Norreys, P.; Notley, M.; Oliver, M.; Roth, M.; Vassura, L.; Zepf, M.; Borghesi, M.; Freeman, R. R.; Kar, S.

    2017-06-01

    A forwardly-peaked bright neutron source was produced using a laser-driven, deuteron-rich ion beam in a pitcher-catcher scenario. A proton-free ion source was produced via target normal sheath acceleration from Au foils having a thin layer of D2O ice at the rear side, irradiated by sub-petawatt laser pulses (˜200 J, ˜750 fs) at peak intensity ˜ 2× {10}20 {{W}} {{cm}}-2. The neutrons were preferentially produced in a beam of ˜70° FWHM cone along the ion beam forward direction, with maximum energy up to ˜40 MeV and a peak flux along the axis ˜ 2× {10}9 {{n}} {{sr}}-1 for neutron energy above 2.5 MeV. The experimental data is in good agreement with the simulations carried out for the d(d,n)3He reaction using the deuteron beam produced by the ice-layered target.

  17. Reaction cross sections for 8He and 14B on proton target for the separation of proton and neutron density distributions

    International Nuclear Information System (INIS)

    Tanaka, Masaomi; Fukuda, Mitsunori; Nishimura, Daiki

    2015-01-01

    We utilized the proton-neutron asymmetry of nucleon–nucleon total cross sections in the intermediate energy region (σ pn ≠σ pp(nn) ) to obtain the information of proton and neutron distributions respectively. We have measured reaction cross sections (σ R ) for 14 B and 8 He on proton targets as isospin asymmetric targets in addition to symmetric ones. Proton and neutron density distributions were derived respectively through the χ 2 -fitting procedure with the modified Glauber calculation. The result suggests a necessity for 14 B of a long tail, and also a necessity for 8 He of a neutron tail. Root-mean-square proton, neutron and matter radii for 14 B and 8 He are also derived. Each radius is consistent with some of the other experimental values and also with some of the several theoretical values. (author)

  18. Preliminary results on neutron production from a Pb/U target irradiated by deuteron beam at 1.25 GeV/amu

    International Nuclear Information System (INIS)

    Fragopoulou, M.; Manolopoulou, M.; Jokic, S.; Zamani, M.; Krivopustov, M.; Sosnin, A.; Stoulos, S.

    2008-01-01

    A spallation neutron source consisted of a cylindrical Pb target and surrounded by uranium blanket was irradiated by deuteron beam 1.25 GeV/amu provided from the Nuclotron accelerator at High Energy Laboratory, JINR, Dubna. For radiation protection purpose a polyethylene shielding was placed around the spallation neutron source. Neutron distributions along the surface of the U-blanket were measured by using solid state nuclear track detectors (SSNTDs) as particle and fission detectors. The neutron distributions appear to be similar to those obtained by proton irradiations. Applying a fitting procedure to the experimental data the inelastic cross section of deuteron in Pb was estimated. The escaping neutron distribution from the polyethylene shielding and parallel to the target was also measured and presented to be two orders of magnitude less than that over the U-blanket surface

  19. Experimental investigation of neutron generation in thick target blocks of Pb, Hg and W with 0.4 to 2.5 GeV proton beams

    International Nuclear Information System (INIS)

    Jahnke, U.; Enke, M.; Filges, D.

    2002-01-01

    Detailed experimental neutron data relevant to the design of the target station of neutron spallation sources have been gathered by the NESSI-collaboration at the COSY accelerator in FZ Juelich. Numerous neutron multiplicity distributions and reaction probabilities have been measured for 0.4 to 2.5 GeV protons bombarding highly segmented target blocks from Pb, Hg and W of up to 35 cm in length and 15 cm in diameter with the intention to provide a comprehensive data base for the improvement and validation of existing reaction simulation codes. (author)

  20. Update of neutron dose yields as a function of energy for protons and deuterons incident on beryllium targets

    International Nuclear Information System (INIS)

    Ten Haken, R.K.; Awschalom, M.; Rosenberg, I.

    1982-11-01

    Neutron absorbed dose yields (absorbed dose rates per unit incident current on targets at a given SAD or SSD) increase with incident charged particle energy for both protons and deuterons. Analyses of neutron dose yield versus incident particle energy have been performed for both deuterons and protons. It is the purpose of this report to update those analyses by pooling all of the more recent published results and to reanalyze the trend of yield, Y, versus incident energy, E, which in the past has been described by an expression of the form Y = aE/sup b/, where a and b are empirical constants. From the reanalyzed trend it is concluded that for a given size cyclotron (E/sub p/ = 2E/sub d/), the dose yields using protons are higher than those using deuterons up to a proton energy E/sub p/ of 64 MeV

  1. 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.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

    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,γ) 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.

  3. Monte Carlo simulation for neutron yield produced by bombarding thick targets with high energy heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Yoon, Moo Hyun; Lee, Hee Seock [POSTECH, Pohang (Korea, Republic of)

    2013-04-15

    One of radiation shielding issues at heavy-ion accelerator facilities is to estimate neutron production by primary heavy ions. A few Monte Carlo transport codes such as FLUKA and PHITS can work with primary heavy ions. Recently IBS/RISP((Rare Isotope Science Project) started to design a high-energy, high-power rare isotope accelerator complex for nuclear physics, medical and material science and applications. There is a lack of experimental and simulated data about the interaction of major beam, {sup 238}U with materials. For the shielding design of the end of first accelerating section section, we calculate a differential neutron yield using the FLUKA code for the interaction of 18.5 MeV/u uranium ion beam with thin carbon stripper of 1.3 μm). The benchmarking studies were also done to prove the yield calculation for 400 MeV/n {sup 131}Xe and other heavy ions. In this study, the benchmarking for Xe-C, Xe-Cu, Xe-Al, Xe-Pb and U-C, other interactions were performed using the FLUKA code. All of results show that the FLUKA can evaluate the heavy ion induced reaction with good uncertainty. For the evaluation of neutron source term, the calculated neutron yields are shown in Fig. 2. The energy of Uranium ion beam is only 18.5 MeV/u, but the energy of produced secondary neutrons was extended over 100 MeV. So the neutron shielding and the damage by those neutrons is expected to be serious. Because of thin stripper, the neutron intensity at forward direction was high. But the the intensity of produced secondary photons was relatively low and mostly the angular property was isotropic. For the detail shielding design of stripper section of RISP rare istope accelerator, the benchmarking study and preliminary evaluation of neutron source term from uranium beam have been carried out using the FLUKA code. This study is also compared with the evaluation results using the PHITS code performed coincidently. Both studies shows that two monte carlo codes can give a good results for

  4. IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

    Science.gov (United States)

    Capote, R.; Trkov, A.; Sin, M.; Pigni, M. T.; Pronyaev, V. G.; Balibrea, J.; Bernard, D.; Cano-Ott, D.; Danon, Y.; Daskalakis, A.; Goričanec, T.; Herman, M. W.; Kiedrowski, B.; Kopecky, S.; Mendoza, E.; Neudecker, D.; Leal, L.; Noguere, G.; Schillebeeckx, P.; Sirakov, I.; Soukhovitskii, E. S.; Stetcu, I.; Talou, P.

    2018-02-01

    Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10-5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE-3.2 Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(nth,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good performance in

  5. Spallation Neutron Emission Spectra in Some Amphoter Target Nuclei by Proton Beam Up to 140 MeV Energy

    International Nuclear Information System (INIS)

    Yildirim, G.

    2008-01-01

    In the present study, the (p,xn) reaction neutron-emission spectra for some amphoter target nuclei as 27 A l, 64 Z n, 120 S n, and 208 P b were investigated up to 140 MeV incident proton energy. The pre-equilibrium calculations were calculated by using the hybrid model, the geometry dependent hybrid model, the full exciton model and the cascade exciton model. The reaction equilibrium component was calculated with a traditional compound nucleus model developed by Weisskopf Ewing. Calculation results have been discussed and compared with the available experimental data in literature

  6. Measurements of Neutron Spectra Produced from a Thick Iron Target Bombarded with 1.5-GeV Protons

    International Nuclear Information System (INIS)

    Meigo, Shin-ichiro; Shigyo, Nobuhiro; Iga, Kiminori; Iwamoto, Yosuke; Kitsuki, Hirohiko; Ishibashi, Kenji; Maehata, Keisuke; Arima, Hidehiko; Nakamoto, Tatsushi; Numajiri, Masaharu

    2005-01-01

    For validation of calculation codes that are employed in the design of accelerator facilities, spectra of neutrons produced from a thick iron target bombarded with 1.5-GeV protons were measured. The calculated results with NMTC/JAM were compared with the present experimental results. It is found that the NMTC/JAM generally shows good agreement with experiment. Furthermore, the calculation gives good agreement with the experiment for the energy region 20 to 80 MeV for iron, whereas the NMTC/JAM gives 50% of the experimental data for the heavy-nuclides such as lead and tungsten

  7. DETECTORS AND EXPERIMENTAL METHODS: Studies of a scintillator-bar detector for a neutron wall at an external target facility

    Science.gov (United States)

    Yu, Yu-Hong; Xu, Hua-Gen; Xu, Hu-Shan; Zhan, Wen-Long; Sun, Zhi-Yu; Guo, Zhong-Yan; Hu, Zheng-Guo; Wang, Jian-Song; Chen, Jun-Ling; Zheng, Chuan

    2009-07-01

    To achieve a better time resolution of a scintillator-bar detector for a neutron wall at the external target facility of HIRFL-CSR, we have carried out a detailed study of the photomultiplier, the wrapping material and the coupling media. The timing properties of a scintillator-bar detector have been studied in detail with cosmic rays using a high and low level signal coincidence. A time resolution of 80 ps has been achieved in the center of the scintillator-bar detector.

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

    International Nuclear Information System (INIS)

    Adam, J.; Barabanov, M.Yu.; 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 139 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 139 La(n, γ) 140 La (τ 1/2 = 40.27 h) was studied using standard procedures of gamma spectroscopy and data analysis. The neutron induced activity of 140 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 with the proton energy. Some comparisons of the experimental results with model estimations based on the LAHET code are also presented. The experiments were carried out using the Nuclotron accelerator of the Laboratory of High Energies (JINR)

  9. 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 ...

  10. About the possibility of use of different types of targets as a neutron source for subcritical nuclear reactor driven by particle beam accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Avdeev, E.F.; Dorokhovich, S.L.; Chusov, I.A. [Obninsk Institute of Nuclear Power Engineering (Russian Federation)

    1995-10-01

    The schemes of jet gas and liquid targets as well as the gastargets with a solid phase dispersion are introduced to use to receive the neutrons admitted to a subcritical reactor core. The possible variants of target position in the reactor are considered, target characteristics are calculated. The authors pay a great attention to the estimation of radioactive products yield receiving due to the interaction of the beam with the target.

  11. Meeting the challenge of homogenous boron targeting of heterogeneous tumors for effective boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Heber, Elisa M.; Trivillin, Veronica A.; Itoiz, Maria E.; Rebagliati, J. Raul; Batistoni, Daniel; Kreimann, Erica L.; Schwint, Amanda E.; Nigg, David W.; Gonzalez, Beatriz N.

    2006-01-01

    BNCT is a tumor cell targeted radiation therapy. Inadequately boron targeted tumor populations jeopardize tumor control. Meeting the to date unresolved challenge of homogeneous targeting of heterogeneous tumors with effective boron carriers would contribute to therapeutic efficacy. The aim of the present study was to evaluate the degree of variation in boron content delivered by boronophenylalanine (BPA), GB-10 (Na 2 10 B 10 H 10 ) and the combined administration of (BPA+GB-10) in different portions of tumor, precancerous tissue around tumor and normal pouch tissue in the hamster cheek pouch oral cancer model. Boron content was evaluated by ICP-AES. The degree of homogeneity in boron targeting was assessed in terms of the coefficient of variation ([S.D./Mean]x100) of boron values. Statistical analysis of the results was performed by one-way ANOVA and the least significant difference test. GB-10 and GB-10 plus BPA achieved respectively a statistically significant 1.8-fold and 3.3-fold increase in targeting homogeneity over BPA. The combined boron compound administration protocol contributes to homogeneous targeting of heterogeneous tumors and would increase therapeutic efficacy of BNCT by exposing all tumor populations to neutron capture reactions in boron. (author)

  12. 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. © 2013 Elsevier Ltd. All rights reserved.

  13. Thermodynamic consideration on self-regulating characteristics of cold neutron source with cylinder annulus type cold moderator cell

    International Nuclear Information System (INIS)

    Kawai, Takeshi; Yoshino, Hiroshi; Kawabata, Yuji; Hino, Masahiro

    2000-01-01

    Shapes of moderator baths of ORPHEE and NIST without bottom of inner cylinder, entering liquid from downward and push down the liquid by steam formed nuclear exotherm to fill inner part of the inner cylinder with steam, require to determine a number of parameters to be optimum to realize a state storing steam in inner cylinder and liquid in shell portion. Then, for a modulator bath with a structure shielding the inner cylinder from shell portion by preparing bottom without any pore and supplying steam into the cylinder through a steam return pipe mounted with pores at its upper portion. By such structure, a cold neutron source with self-balance-ability and capable of following output without time delaying. And, its liquid volume can also be controlled by system pressure. And that, as its structure is simple, it has another characteristic that its connection structure of transmission pipe portion with moderator bath portion. (G.K.)

  14. Slotted rotatable target assembly and systematic error analysis for a search for long range spin dependent interactions from exotic vector boson exchange using neutron spin rotation

    Science.gov (United States)

    Haddock, C.; Crawford, B.; Fox, W.; Francis, I.; Holley, A.; Magers, S.; Sarsour, M.; Snow, W. M.; Vanderwerp, J.

    2018-03-01

    We discuss the design and construction of a novel target array of nonmagnetic test masses used in a neutron polarimetry measurement made in search for new possible exotic spin dependent neutron-atominteractions of Nature at sub-mm length scales. This target was designed to accept and efficiently transmit a transversely polarized slow neutron beam through a series of long open parallel slots bounded by flat rectangular plates. These openings possessed equal atom density gradients normal to the slots from the flat test masses with dimensions optimized to achieve maximum sensitivity to an exotic spin-dependent interaction from vector boson exchanges with ranges in the mm - μm regime. The parallel slots were oriented differently in four quadrants that can be rotated about the neutron beam axis in discrete 90°increments using a Geneva drive. The spin rotation signals from the 4 quadrants were measured using a segmented neutron ion chamber to suppress possible systematic errors from stray magnetic fields in the target region. We discuss the per-neutron sensitivity of the target to the exotic interaction, the design constraints, the potential sources of systematic errors which could be present in this design, and our estimate of the achievable sensitivity using this method.

  15. 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)

  16. 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...

  17. EURISOL-DS Multi-MW Target Comparative Neutronic Performance of the Baseline Configuration vs. the Hg-Jet Option

    CERN Document Server

    Herrera-Martínez, A

    2006-01-01

    This technical report summarises the comparative study between several design options for the Multi-MW target station performed within Task #2 of the European Isotope Separation On-Line Radioactive Ion Beam Facility Design Study (EURISOL DS) [1]. Previous analyses were carried out, using the Monte Carlo code FLUKA [2], to determine optimal values for relevant parameters in the target design [3] and to analyse a preliminary Multi-MW target assembly configuration [4]. The second report showed that the aimed fission rates, i.e. ~1015 fissions/s, could be achieved with such a configuration. Nevertheless, a preliminary study of the target assembly integration [5] suggested reducing some of the dimensions. Moreover, the yields of specific isotopes have yet to be assessed and compared to other target configurations. This note presents a detailed comparison of the baseline configuration and the Hg-jet option, in terms of primary and neutron distribution, power densities and fission product yields. A scaled-down versi...

  18. Thermal-hydraulic performance of a water-cooled tungsten-rod target for a spallation neutron source

    International Nuclear Information System (INIS)

    Poston, D.I.

    1997-08-01

    A thermal-hydraulic (T-H) analysis is conducted to determine the feasibility and limitations of a water-cooled tungsten-rod target at powers of 1 MW and above. The target evaluated has a 10-cm x 10-cm cross section perpendicular to the beam axis, which is typical of an experimental spallation neutron source - both for a short-pulse spallation source and long-pulse spallation source. This report describes the T-H model and assumptions that are used to evaluate the target. A 1-MW baseline target is examined, and the results indicate that this target should easily handle the T-H requirements. The possibility of operating at powers >1 MW is also examined. The T-H design is limited by the condition that the coolant does not boil (actual limits are on surface subcooling and wall heat flux); material temperature limits are not approached. Three possible methods of enhancing the target power capability are presented: reducing peak power density, altering pin dimensions, and improving coolant conditions (pressure and temperature). Based on simple calculations, it appears that this target concept should have little trouble reaching the 2-MW range (from a purely T-H standpoint), and possibly much higher powers. However, one must keep in mind that these conclusions are based solely on thermal-hydraulics. It is possible, and perhaps likely, that target performance could be limited by structural issues at higher powers, particularly for a short-pulse spallation source because of thermal shock issues

  19. Study of Ne and Kr production in Mg, Al, Rb, Sr and Y targets by 0-180 MeV neutrons. Cosmochemical application

    International Nuclear Information System (INIS)

    Bertin, P.

    1989-07-01

    High sensitivity mass spectrometry technique has been used to measure production of noble gases Ne and Kr induced by 0-180 MeV neutrons in Mg, Al, Rb, Sr and Y targets. This experiment allowed us an evaluation of the implied excitation functions, in an energy range where no experimental data were available. These results have exhibited the importance of secondary neutrons induced in the interaction of cosmic rays with meteorites and moon surface [fr

  20. The thick-target 9Be(d,n) neutron spectra for deuteron energies between 2.6 and 7.0-MeV

    International Nuclear Information System (INIS)

    Meadows, J.W.

    1991-11-01

    The measurement of the zero deg. neutron spectra and yields from deuterons incident on thick beryllium metal targets is described. 235 U and 238 U fission ion chambers were used as neutron detectors to span the neutron energy range above 0.05-MeV with a time resolution of ≤ 3 nanosec. Measurements were made for incident deuteron energies from 2.6 to 7.0-MeV, at 0.4-MeV intervals, using time-of-flight techniques with flight paths of 2.7 and 6.8 meters. The results are presented in graphical form and in tables

  1. 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...

  2. Improved Dose Targeting for a Clinical Epithermal Neutron Capture Beam Using Optional 6Li Filtration

    International Nuclear Information System (INIS)

    Binns, Peter J.; Riley, Kent J.; Ostrovsky, Yakov; Gao Wei; Albritton, J. Raymond; Kiger, W.S.; Harling, Otto K.

    2007-01-01

    Purpose: The aim of this study was to construct a 6 Li filter and to improve penetration of thermal neutrons produced by the fission converter-based epithermal neutron beam (FCB) for brain irradiation during boron neutron capture therapy (BNCT). Methods and Materials: Design of the 6 Li filter was evaluated using Monte Carlo simulations of the existing beam line and radiation transport through an ellipsoidal water phantom. Changes in beam performance were determined using three figures of merit: (1) advantage depth (AD), the depth at which the total biologically weighted dose to tumor equals the maximum weighted dose to normal tissue; (2) advantage ratio (AR), the ratio of the integral tumor dose to that of normal tissue averaged from the surface to the AD; and (3) advantage depth dose rate (ADDR), the therapeutic dose rate at the AD. Dosimetry performed with the new filter installed provided calibration data for treatment planning. Past treatment plans were recalculated to illustrate the clinical potential of the filter. Results: The 8-mm-thick Li filter is more effective for smaller field sizes, increasing the AD from 9.3 to 9.9 cm, leaving the AR unchanged at 5.7 but decreasing the ADDR from 114 to 55 cGy min -1 for the 12 cm diameter aperture. Using the filter increases the minimum deliverable dose to deep seated tumors by up to 9% for the same maximum dose to normal tissue. Conclusions: Optional 6 Li filtration provides an incremental improvement in clinical beam performance of the FCB that could help to establish a therapeutic window in the future treatment of deep-seated tumors

  3. A polarized solid {sup 3}He target for neutron transmission experiments

    Energy Technology Data Exchange (ETDEWEB)

    Keith, C.D. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Gould, C.R. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Haase, D.G. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Huffman, P.R. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Roberson, N.R. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Seely, M.L. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Wilburn, W.S. [Duke University, Durham, NC 27708-0308 (United States)]|[Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)

    1995-04-01

    We describe the construction and operation of a solid {sup 3}He polarized nuclear target which we have used for measurements of the spin dependence of the n-{sup 3}He interaction at MeV energies. The target, which contains 0.4 mole of {sup 3}He was polarized to 38% at 12 mK in a field of 7 T. The target is suitable for nuclear physics measurements which are insensitive to the large magnetic field and produce beam heating of tenths of microwatts.We discuss refinements and paths to improved solid {sup 3}He targets at higher polarizations and lower fields. ((orig.)).

  4. Measurements of neutron spectra produced from a thick tungsten target bombarded with 0.5- and 1.5-GeV protons

    International Nuclear Information System (INIS)

    Meigo, Shin-ichiro; Takada, Hiroshi

    2002-01-01

    For validation of calculation codes that are employed in the design of pulse spallation neutron source and accelerator driven system, spectrum of neutrons produced from a thick target plays an important role. However, appropriate experimental data were scarce for the incident energies higher than 0.8 GeV. In this study, the spectrum from a thick tungsten target was measured. The experiment was carried out at the π2 beam line of the 12-GeV proton synchrotron at KEK. The tungsten target was bombarded by the 0.5- and 1.5-GeV secondary protons. Spectrum of neutrons was measured by the time-of-flight technique using organic scintillators of NE213. The calculated result with NMTC/JAM and MCNP-4A is compared with the measured data. It is found that the NMTC/JAM generally gives a good agreement with experiment. The NMTC/JAM, however, gives 50% lower neutron flux in the energy region 20∼80 MeV, which is consistent with the results in previous comparison of lead target. For the neutrons between 20 and 80 MeV, the calculation using with the in-medium nucleon-nucleon cross sections reproduced the experiment fairly well. (author)

  5. Targeting the brain: considerations in 332 consecutive patients treated by deep brain stimulation (DBS) for severe neurological diseases.

    Science.gov (United States)

    Franzini, Angelo; Cordella, Roberto; Messina, Giuseppe; Marras, Carlo Efisio; Romito, Luigi Michele; Albanese, Alberto; Rizzi, Michele; Nardocci, Nardo; Zorzi, Giovanna; Zekaj, Edvin; Villani, Flavio; Leone, Massimo; Gambini, Orsola; Broggi, Giovanni

    2012-12-01

    Deep brain stimulation (DBS) extends the treatment of some severe neurological diseases beyond pharmacological and conservative therapy. Our experience extends the field of DBS beyond the treatment of Parkinson disease and dystonia, including several other diseases such as cluster headache and disruptive behavior. Since 1993, at the Istituto Nazionale Neurologico "Carlo Besta" in Milan, 580 deep brain electrodes were implanted in 332 patients. The DBS targets include Stn, GPi, Voa, Vop, Vim, CM-pf, pHyp, cZi, Nacc, IC, PPN, and Brodmann areas 24 and 25. Three hundred patients are still available for follow-up and therapeutic considerations. DBS gave a new therapeutic chance to these patients affected by severe neurological diseases and in some cases controlled life-threatening pathological conditions, which would otherwise result in the death of the patient such as in status dystonicus, status epilepticus and post-stroke hemiballismus. The balance of DBS in severe neurological disease is strongly positive even if further investigations and studies are needed to search for new applications and refine the selection criteria for the actual indications.

  6. Spectrometers for compact neutron sources

    Science.gov (United States)

    Voigt, J.; Böhm, S.; Dabruck, J. P.; Rücker, U.; Gutberlet, T.; Brückel, T.

    2018-03-01

    We discuss the potential for neutron spectrometers at novel accelerator driven compact neutron sources. Such a High Brilliance Source (HBS) relies on low energy nuclear reactions, which enable cryogenic moderators in very close proximity to the target and neutron optics at comparably short distances from the moderator compared to existing sources. While the first effect aims at increasing the phase space density of a moderator, the second allows the extraction of a large phase space volume, which is typically requested for spectrometer applications. We find that competitive spectrometers can be realized if (a) the neutron production rate can be synchronized with the experiment repetition rate and (b) the emission characteristics of the moderator can be matched to the phase space requirements of the experiment. MCNP simulations for protons or deuterons on a Beryllium target with a suitable target/moderator design yield a source brightness, from which we calculate the sample fluxes by phase space considerations for different types of spectrometers. These match closely the figures of todays spectrometers at medium flux sources. Hence we conclude that compact neutron sources might be a viable option for next generation neutron sources.

  7. 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.

  8. Comparison of (alpha, n) thick-target neutron yields and spectra from ORIGEN-S and SOURCES

    International Nuclear Information System (INIS)

    Brown, T.H.; Wilson, W.B.; Perry, R.T.; Charlton, W.S.

    1998-01-01

    Both ORIGEN-S and SOURCES generate thick-target neutron yields and energy spectra from (α,n) reactions in homogeneous materials. SOURCES calculates yield and spectra for any material containing α-emitting and (α,n) target elements by simulating reaction physics, using α-emission energy spectra, elemental stopping cross sections, (α,n) cross sections for target nuclei, and branching fractions to produce-nuclide energy levels. This methodology results in accurate yield and spectra. ORIGEN-S has two options for calculating yields and spectra. The UO 2 option (default) estimates yields and spectra assuming the input α-emitters to be infinitely dilute in UO 2 . The borosilicate-glass option estimates yields from the total input material composition and generates spectra purportedly representative of spectra generated by 238 Pu, 241 Am, 242 Cm, and 244 Cm infinitely dilute in borosilicate glass, even if none of these four α-emitters are present in the input material composition. Because yields from the borosilicate-glass option in ORIGEN-S are based on entire input material composition and are reasonably accurate, the same is often assumed to be true for spectra. The input/output functionality of the borosilicate-glass option, along with ambiguity in ORIGEN-S documentation, gives the incorrect impression that spectra representative of input compositions are generated. This impression is reinforced by wide usage of the SCALE code system and its ORIGEN-S module and their sponsorship by the US Nuclear Regulatory Commission

  9. A method for measuring the corrosion rate of materials in spallation neutron source target/blanket cooling loops

    International Nuclear Information System (INIS)

    Lillard, R.S.; Butt, D.P.

    1999-01-01

    This paper summarizes the ongoing evaluation of the susceptibility of materials in accelerator target/blanket cooling loops to corrosion. To simulate the exposure environment in a target/blanket cooling loop, samples were irradiated by an 800 MeV proton beam at the A6 Target Station of the Los Alamos Neutron Science Center (LANSCE). To accomplish this, a cooling water loop capable of exposing corrosion samples to an 800 MeV proton beam at currents upwards of 1 mA was constructed. This loop allowed control and evaluation hydrogen water chemistry, water conductivity, and solution pH. Specially designed ceramic sealed samples were used to measure the real-time corrosion rates of materials placed directly in the proton beam using electrochemical impedance spectroscopy (EIS). EIS was also used to measure real-time corrosion rates of samples that were out of the proton beam and downstream from the in-beam samples. These out-of-beam probes primarily examined the effects of long lived water radiolysis products from proton irradiation on corrosion rates. An overview of the LANSCE corrosion loop, the corrosion probes, and data from an in-beam alloy 718 probe are presented

  10. Investigation of thick-target neutron emission from Be-9(d,n)B-10 at E/sub d/ = 7 MeV for angles other than zero degrees

    International Nuclear Information System (INIS)

    Smith, D.L.; Meadows, J.W.; Guenther, P.T.

    1985-01-01

    Double-differential measurements of neutron emission from a thick beryllium target bombarded with 7-MeV deuterons are made for neutrons above 800 keV, over the angular range of 0 to 155 0 . The angular dependence of the neutron yield is found to be quite anisotropic. The importance of this anisotropy in integral neutron-induced reaction cross-section investigations is illustrated. 7 refs.,

  11. Exploring the Gaps in Practical Ethical Guidance for Animal Welfare Considerations of Field Interventions and Innovations Targeting Dogs and Cats

    Science.gov (United States)

    Tasker, Louisa; Getty, Susan F.; Briggs, Joyce R.; Benka, Valerie A.W.

    2018-01-01

    Simple Summary Large populations of domestic dogs and cats are found living, or in close association with humans. They are often targeted by field interventions or innovations to enhance their welfare or to reduce conflict with communities or wildlife. Ethical review is a cornerstone of responsible engagement that aims to promote animal and human wellbeing. For the review process to be robust, identifying and understanding the ethical dilemmas that may be encountered when working with dogs and cats in field contexts, together with their human communities and in multi-stakeholder partnerships would be advantageous. We explored existing guidance from other disciplines (regulated animal research, veterinary and human clinical trials, and research conducted on wildlife) and identified gaps in ethical frameworks that do not adequately address the specific and practical needs of nongovernmental or intergovernmental organizations, government agencies or independent researchers working with dogs and cats in field contexts. Navigating practical ethical concerns in complex, highly variable field contexts necessitates the development of additional resources that can better inform reliable ethical review processes, and subsequently enhance the humaneness and effectiveness of future interventions and innovations. Abstract Domestic dogs (Canis lupus familiaris) and cats (Felis silvestris catus) are common species targeted by nongovernmental or intergovernmental organizations, veterinarians and government agencies worldwide, for field interventions (e.g., population management, rabies vaccination programs) or innovations (e.g., development of technologies or pharmaceuticals to improve animal welfare). We have a moral responsibility to ensure that the conduct of this work is humane for dogs or cats, and to consider the human communities in which the animals live. Ethical review is widely accepted as being integral to responsible practice, and it is fundamental to good science that

  12. Neutron production in bombardments of thin and thick W, Hg, Pb targets by 0.4, 0.8, 1.2, 1.8 and 2.5 GeV protons

    International Nuclear Information System (INIS)

    Letrourneau, A.; Galin, J.; Goldenbaum, F.; Lott, B.; Peghaire, A.; Enke, M.; Hilscher, D.; Jahnke, U.; Nuenighoff, K.; Filges, D.; Neef, R.D.; Paul, N.; Schaal, H.; Sterzenbach, G.; Tietze, A.

    2000-05-01

    Neutron experimental data relevant to the design of the target of neutron spallation sources are presented and discussed. The data include the reaction cross sections for W, Hg and Pb investigated with 0.4, 0.8, 1.2, 1.8 and 2.5 GeV proton beams as well as the neutron production, neutron multiplicity distribution, as determined event per event using a high efficiency detector. The production as a function of target material is investigated for both thin (with a single reaction) and thick targets (multiple reactions). Comparisons are made with the predictions of a high energy transport code. (authors)

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

    CERN Document Server

    Agosteo, S; Foglio-Para, A; Gini, L; Mitaroff, W A; Silari, Marco; 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 deg. 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.

  14. Determination of intensity and energy spectrum of neutrons by bombardment of thallium-203 thick target and its copper substrate with 28.5 MeV protons

    International Nuclear Information System (INIS)

    Hajiloo, N.; Raisali, Gh.; Hamidi, S.; Aslani, Gh.

    2007-01-01

    In this research we have determined neutrons spectrum and the intensity that produced from thallium target bombardment. We have applied SRIM and ALICE computer codes to thallium target and its copper substrate for 145 μA of 28.5 MeV incident proton beam from cyclotron Cyclone30. Because of the energy degradation of protons while passing through the thallium target and its copper substrate, the average energy of protons in different depths has been calculated by using SRIM computer code. Then, by applying ALICE computer code for each sub-layer, the neutron production cross sections and their energy spectrum have been calculated to determine the total neutron intensity and spectrum. Using the calculated neutron intensity of 1.22x10 13 n/s as the source, the equivalent dose rate at the distance 6 meters from the target has been calculated by MCNP computer code and the result has been compared with the measured value. The Pb 201 activity has also been calculated as 13.5 Curies. The measured Pb 201 activity by Curie meter CAPINTEC CRC-712 is 13.1 Ci which is in reasonable agreement with the calculated value, bearing in mind the uncertainties in the proposed models and the measurements

  15. Measurement of neutron activation cross sections in the energy range between 2 and 7 MeV by using a Ti-deuteron target and a deuteron gas target

    Energy Technology Data Exchange (ETDEWEB)

    Senga, T.; Sakane, H.; Shibata, M.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Kasugai, Yoshimi; Ikeda, Yujiro; Takeuchi, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-03-01

    Using a Ti-deuteron target in the neutron energy range between 2 and 4.5 MeV and a deuteron gas target between 4.5 and 7 MeV, mono-energetic neutrons could be generated enough for activation cross section measurements. The KN-3750 Van de Grraff accelerator at Nagoya University and the Fusion Neutronics Source (FNS) at Japan Atomic Energy Research Institute (JAERI) were used. Preliminary results of activation cross sections were obtained for reactions of {sup 27}Al(n,p){sup 27}Mg, {sup 47}Ti(n,p){sup 47}Sc, {sup 58}Ni(n,p){sup 58}Co. The evaluation data of JENDL-3.2 showed reasonable agreement with our results. (author)

  16. Advances in radiation-hydrodynamics and atomic physics simulation for current and new neutron-less targets

    International Nuclear Information System (INIS)

    Velarde, G.; Minguez, E.; Bravo, E.

    2003-01-01

    We present advances in advanced fusion cycles, atomic physics and radiation hydrodynamics. With ARWEN code we analyze a target design for ICF based on jet production. ARWEN is 2D Adaptive Mesh Refinement fluid dynamic and multigroup radiation transport. We are designing, by using also ARWEN, a target for laboratory simulation of astrophysical phenomena. We feature an experimental device to reproduce collisions of two shock waves, scaled to roughly represent cosmic supernova remnants. Opacity calculations are obtained with ANALOP code, which uses parametric potentials fitting to self-consistent potentials. It includes temperature and density effects by linearized Debye-Hueckel and it treats excited configurations and H+He-like lines. Advanced fusion cycles, as the a neutronic proton-boron 11 reaction, require very high ignition temperatures. Plasma conditions for a fusion-burning wave to propagate at such temperatures are rather extreme and complex, because of the overlapping effects of the main energy transport mechanisms. Calculations on the most appropriate ICF regimes for this purpose are presented. (author)

  17. An active target for the accelerator-based transmutation system

    Energy Technology Data Exchange (ETDEWEB)

    Grebyonkin, K.F. [Institute of Technical Physics, Chelyabinsk (Russian Federation)

    1995-10-01

    Consideration is given to the possibility of radical reduction in power requirements to the proton accelerator of the electronuclear reactor due to neutron multiplication both in the blanket and the target of an active material. The target is supposed to have the fast-neutron spectrum, and the blanket-the thermal one. The blanket and the target are separated by the thermal neutrons absorber, which is responsible for the neutron decoupling of the active target and blanket. Also made are preliminary estimations which illustrate that the realization of the idea under consideration can lead to significant reduction in power requirements to the proton beam and, hence considerably improve economic characteristics of the electronuclear reactor.

  18. 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)

  19. Neutron generator control system

    International Nuclear Information System (INIS)

    Peelman, H.E.; Bridges, J.R.

    1981-01-01

    A method is described of controlling the neutron output of a neutron generator tube used in neutron well logging. The system operates by monitoring the target beam current and comparing a function of this current with a reference voltage level to develop a control signal used in a series regulator to control the replenisher current of the neutron generator tube. (U.K.)

  20. 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

    2018-02-01

     Based on evaluation and examination results of students, a necessity for improvement of so far purely instructor-based radiological teaching at the local institution was determined. Aim of our study was to use one out of eight seminars to exemplify adaptation of the teaching concept according to learning theory knowledge, to determine the resulting effects and to interpret them.  The institutional review board approved the prospective study of the seminar conversion, which was performed after the end of the winter semester 2015/2016. Didactically, this included a course split into online preparation, attendance phase and online follow-up with integration of interactive scaffolding, practice-oriented clinical teaching according to Stanford, Peyton skills transfer and extensive feedback into the attendance phase. At the beginning and at the end of each course, each student filled in identical, standardized questionnaires (n = 256 before and after conversion) using a 5-point Likert scale (1: very good; to 5: deficient) and additionally answered two randomly chosen written examination questions from a content-adapted questionnaire pool of the last five years. For statistical evaluation, the Mann-Whitney U-Test was used for evaluation data and Fisher's Exact test for exam questions.  Before/after conversion, the subjective total evaluation score of students was 3.22 (mean value) ± 1.51 (standard deviation) / 1.66 ± 0.78 (p theory concepts with reasonable effort.. · In a test seminar this improved the evaluation results of the teaching unit by the students.. · In addition, this also led to a higher rate of correctly answered examination questions from past state examinations.. · This supports further steps towards excellent radiological teaching.. · 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 R

  1. 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

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

    International Nuclear Information System (INIS)

    Carpenter J.M.

    1996-01-01

    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

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

    International Nuclear Information System (INIS)

    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

  4. 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.

  5. Moderator materials for the Spallation Neutron Source

    International Nuclear Information System (INIS)

    Charlton, L.A.

    1999-01-01

    The Spallation Neutron Source (SNS) is a neutron source providing intense neutron fluxes that will be used for performing a large variety of neutron scattering experiments. SNS is to be completed and start operation in 2005. Protons will be accelerated to 1 GeV, stored in an accumulator ring, and then injected into a neutron-producing target. After leaving the target (Hg in the ca/se of SNS), the neutrons are prepared for experiments by first using a moderator to impose energy and width requirements on the neutron pulse. One of the most important ingredients is the moderator material. Four materials that are commonly used and that were considered for use in SNS are liquid hydrogen (L-H 2 ), liquid water (L-H 2 O), liquid methane (L-CH 4 ), and solid methane (S-CH 4 ). The spectra (neutron current versus neutron energy) for these four materials are shown. As may be seen, at low neutron energies ( 4 , which produces up to four times as many neutrons in this energy range as L-H 2 . The problem with the material is the internal storage of energy that can be spontaneously and explosively released. At energies of just above 10 MeV, the most effective moderator material is L-CH 4 . Polymerization problems, however, preclude its use at high powers (again such as in SNS), where the buildup of undesirable materials becomes prohibitive. This is, however, an important energy range for neutron experiments. Preliminary consideration is being given to a composite moderator that contains two adjacent sections, one of L-H 2 and one of L-H 2 O, which produces a spectrum that is very similar to L-CH 4

  6. 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.

  7. Spallation neutron sources

    International Nuclear Information System (INIS)

    Fraser, J.S.; Bartholomew, G.A.

    1983-01-01

    The principles and theory of spallation neutron sources are outlined and a comparison is given with other types of neutron source. A summary of the available accelerator types for spallation neutron sources and their advantages and disadvantages is presented. Suitable target materials are discussed for specific applications, and typical target assemblies shown. (U.K.)

  8. 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

  9. Optimization of the testing volumes with respect to neutron flux levels in the two-target high flux D-Li neutron source for the international fusion materials irradiation facility

    International Nuclear Information System (INIS)

    Kelleher, W.P.; Varsamis, G.L.

    1989-01-01

    An economic and fusion-relevant source of high-energy neutrons is an essential element in the fusion nuclear technology and development program. This source can be generated by directing a high energy deuteron beam onto a flowing liquid lithium target, producing neutrons via the D-Lithium stripping reaction. Previous work on this type of source concentrated on a design employing one deuteron beam of modest amperage. This design was shown to have a relatively small testing volume with high flux gradients and was therefor considered somewhat unattractive from a materials testing standpoint. A design using two lithium targets and two high-amperage beams has recently been proposed. This two beam design has been examined in an effort to maximize the test volume while minimizing the flux gradients and minimizing the effect of radiation damage on one target due to the other. A spatial, energy and angle dependent neutron source modeling the D-Lithium source was developed. Using this source, a 3-dimensional map of uncollided flux within the test volume was calculated. The results showed that the target separation has little effect on the available experimental volume and that a testing volume of ∼35 liters is available with a volume averaged flux above 10 14 n/cm 2 /s. The collided flux within the test volume was then determined by coupling the source model with a Monte Carlo code. The spectral effects of the high-energy tail in the flux were examined and evaluated as to possible effects on materials response. Calculations comparing the radiation damage to materials from the D-Lithium source to that cause by a standard DT fusion first-wall neutron flux spectrum showed that the number of appm and dpa, as well as the ratio appm/dpa and dpa/MW/m 2 are within 30% for the two sources. 8 refs., 8 figs

  10. Industrial production and purification of 32P by sulfur irradiation with partially moderated neutron fluxes and target melting

    International Nuclear Information System (INIS)

    Alanis, J.; Navarrete, M.

    2007-01-01

    Target purification of S α is carried out by distillation at 444±2 deg C under N atmosphere and diluting the vapors in CS 2 . The solution is filtered through fiberglass, Teflon and cellulose to obtain S α by CS 2 evaporation. Once 30 g of this target are irradiated with fast neutron fluxes from 4.5 to 7.4 x 10 12 n x cm -2 x s -1 from 6 to 12 hours, the nuclear reaction 32 S(n,p) 32 P takes place. So, the irradiated S α sample is placed in a Pyrex container situated inside a furnace as the most important piece of equipment in one aluminum and Lucite glove box. The distillation of irradiated sulfur takes place at 444±2 deg C under N atmosphere during 1-2 hours. The vapors are connected to a sulfur diluter containing 20% CS 2 aqueous solution, followed by an activated carbon filter and the two similar additional sulfur diluters. Once cooled, the distillation chamber keeps the radioactive, carrier-free 32 P stuck to the wall. Then 25-50 ml of 0.1N HCl acid was injected by suction and heated again at 110±2 deg C during 1 hour. The corresponding chemical reaction takes place and the labeled H 3 32 PO 4 solution is produced. In such a way, industrial production of 32 P labeled molecules has started in Mexico, with an initial production of 3700-5550 MBq per week. (author)

  11. Angular distribution measurements of photo-neutron yields produced by 2.0 GeV electrons incident on thick targets

    International Nuclear Information System (INIS)

    Lee, H. S.; Ban, S.; Sanami, T.; Takahashi, K.; Sato, T.; Shin, K.; Chung, C.

    2005-01-01

    A study of differential photo-neutron yields by irradiation with 2 GeV electrons has been carried out. In this extension of a previous study in which measurements were made at an angle of 90 deg. relative to incident electrons, the differential photo-neutron yield was obtained at two other angles, 48 deg. and 140 deg., to study its angular characteristics. Photo-neutron spectra were measured using a pulsed beam time-of-flight method and a BC418 plastic scintillator. The reliable range of neutron energy measurement was 8-250 MeV. The neutron spectra were measured for 10 Xo-thick Cu, Sn, W and Pb targets. The angular distribution characteristics, together with the previous results for 90 deg., are presented in the study. The experimental results are compared with Monte Carlo calculation results. The yields predicted by MCNPX 2.5 tend to underestimate the measured ones. The same trend holds for the comparison results using the EGS4 and PICA3 codes. (authors)

  12. Angular distribution measurements of photo-neutron yields produced by 2.0 GeV electrons incident on thick targets.

    Science.gov (United States)

    Lee, Hee-Seock; Ban, Syuichi; Sanami, Toshiya; Takahashi, Kazutoshi; Sato, Tatsuhiko; Shin, Kazuo; Chung, Chinwha

    2005-01-01

    A study of differential photo-neutron yields by irradiation with 2 GeV electrons has been carried out. In this extension of a previous study in which measurements were made at an angle of 90 degrees relative to incident electrons, the differential photo-neutron yield was obtained at two other angles, 48 degrees and 140 degrees, to study its angular characteristics. Photo-neutron spectra were measured using a pulsed beam time-of-flight method and a BC418 plastic scintillator. The reliable range of neutron energy measurement was 8-250 MeV. The neutron spectra were measured for 10 Xo-thick Cu, Sn, W and Pb targets. The angular distribution characteristics, together with the previous results for 90 degrees, are presented in the study. The experimental results are compared with Monte Carlo calculation results. The yields predicted by MCNPX 2.5 tend to underestimate the measured ones. The same trend holds for the comparison results using the EGS4 and PICA3 codes.

  13. Fast neutron spectrometry by bolometers lithium target for the reduction of background experiences of direct detection of dark matter

    International Nuclear Information System (INIS)

    Gironnet, J.

    2010-01-01

    Fast neutron spectrometry is a common interest for both direct dark matter detection and for nuclear research centres. Fast neutrons are usually detected indirectly. Neutrons are first slowed down by moderating materials for being detected in low energy range. Nevertheless, these detection techniques are and are limited in energy resolution. A new kind of fast neutron spectroscopy has been developed at the Institut d'Astrophysique Spatiale (IAS) in the aim of having a better knowledge of neutron backgrounds by the association of the bolometric technique with neutron sensitive crystals containing Li. Lithium-6 is indeed an element which has one the highest cross section for neutron capture with the 6 Li(n,α) 3 H reaction. This reaction releases 4,78 MeV tagging energetically each neutron capture. In particular for fast neutrons, the total energy measured by the bolometer would be the sum of this energy reaction and of the incoming fast neutron energy. To validate this principle, a spectrometer for fast neutrons, compact and semi-transportable, was built in IAS. This cryogenic detector, operated at 300 - 400 mK, consists of a 0.5 g LiF 95% 6 Li enriched crystal read out by a NTD-Ge sensor. This PhD thesis was on the study of the spectrometer characteristics, from the first measurements at IAS, to the measurements in the nuclear research centre of the Paul Scherrer Institute (PSI) until the final calibration with the Amande instrument of the Institut de Radioprotection et de Surete Nucleaire (IRSN). (author)

  14. 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.

  15. Neutron capture therapy (NCT) and in-hospital neutron irradiator (IHNI) a new technology on binary targeting radiation therapy of cancer

    International Nuclear Information System (INIS)

    Zhou Yongmao

    2009-01-01

    BNCT is finally becoming 'a new option against cancer'. The difficulties for its development progress of that firstly is to improve the performance of boron compounds,secondly, it is the requirements of quantification and accuracy upon radiation dosimetry evaluation in clinical trials. Furthermore, that is long anticipation on hospital base neutron sources. It includes dedicated new NCT reactor, accelerator based neutron sources, and isotope source facilities. In addition to reactors, so far, the technology of other types of sources for clinical trials is not yet completely proven. The In-Hospital Neutron Irradiator specially designed for NCT, based on the MNSR successfully developed by China, can be installed inside or near the hospital and operated directly by doctors. The Irradiator has two neutron beams for respective treatment of the shallow and deep tumors. It is expected to initiate operation in the end of this year. It would provide a safe, low cost, and effective treatment tool for the NCT routine application in near future. (authors)

  16. Fiscal year 1976T (add-on quarter) DT fusion neutron irradiations and dosimetry at the LLL rotating target neutron source

    International Nuclear Information System (INIS)

    MacLean, S.C.

    1977-01-01

    The DT fusion neutron irradiation of more than 90 samples during seven irradiation periods (beam-on time of more than 430.9 hours) is described. Experiments from 15 individuals representing six institutions are summarized. The numbers of UCID dosimetry reports detailing each of the irradiations is given

  17. 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

    International Nuclear Information System (INIS)

    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

  18. Sources of polarized neutrons

    International Nuclear Information System (INIS)

    Walter, L.

    1983-01-01

    Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

  19. Neutron production from 40 GeV/c mixed proton/pion beam on copper, silver and lead targets in the angular range 30-135 deg

    Energy Technology Data Exchange (ETDEWEB)

    Agosteo, S. [Dipartimento di Ingegneria Nucleare, Politecnico di Milano, via Ponzio 34/3, 20133 Milan (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, 20133 Milan (Italy); Birattari, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Milano, via Celoria 16, 20133 Milan (Italy); Universita degli Studi di Milano, Dipartimento di Fisica, via Celoria 16, 20133 Milan (Italy); Dimovasili, E. [CERN, 1211 Geneva 23 (Switzerland); Foglio Para, A. [Dipartimento di Ingegneria Nucleare, Politecnico di Milano, via Ponzio 34/3, 20133 Milan (Italy); Silari, M. [CERN, 1211 Geneva 23 (Switzerland)]. E-mail: marco.silari@cern.ch; Ulrici, L. [CERN, 1211 Geneva 23 (Switzerland); Vincke, H. [CERN, 1211 Geneva 23 (Switzerland)

    2005-02-01

    The neutron emission from 50 mm thick copper, silver and lead targets bombarded by a mixed proton/pion beam with momentum of 40 GeV/c were measured at the CERN Super Proton Synchrotron. The neutron yield and spectral fluence per incident particle on target were measured with an extended range Bonner sphere spectrometer in the angular range 30-135 deg with respect to the beam direction. Monte Carlo simulations with the FLUKA code were performed to provide a priori information for the unfolding of the experimental data. The spectral fluences show two peaks, an isotropic evaporation component centred at 3 MeV and a high-energy peak sitting around 100-150 MeV. The experimental neutron yields are given in four energy bins: <100 keV, 0.1-20 MeV, 20-500 MeV and 0.5-2 GeV. The total yields show a systematic discrepancy of 30-50%, with a peak of 70% at the largest angles, with respect to the results of the Monte Carlo simulations, which it is believed to be mainly due to uncertainties in the beam normalization factor. Analytic expressions are given for the variation of the integral yield as a function of emission angle and of target mass number.

  20. Neutron production from 40 GeV/c mixed proton/pion beam on copper, silver and lead targets in the angular range 30-135 deg

    International Nuclear Information System (INIS)

    Agosteo, S.; Birattari, C.; Dimovasili, E.; Foglio Para, A.; Silari, M.; Ulrici, L.; Vincke, H.

    2005-01-01

    The neutron emission from 50 mm thick copper, silver and lead targets bombarded by a mixed proton/pion beam with momentum of 40 GeV/c were measured at the CERN Super Proton Synchrotron. The neutron yield and spectral fluence per incident particle on target were measured with an extended range Bonner sphere spectrometer in the angular range 30-135 deg with respect to the beam direction. Monte Carlo simulations with the FLUKA code were performed to provide a priori information for the unfolding of the experimental data. The spectral fluences show two peaks, an isotropic evaporation component centred at 3 MeV and a high-energy peak sitting around 100-150 MeV. The experimental neutron yields are given in four energy bins: <100 keV, 0.1-20 MeV, 20-500 MeV and 0.5-2 GeV. The total yields show a systematic discrepancy of 30-50%, with a peak of 70% at the largest angles, with respect to the results of the Monte Carlo simulations, which it is believed to be mainly due to uncertainties in the beam normalization factor. Analytic expressions are given for the variation of the integral yield as a function of emission angle and of target mass number

  1. Neutron production from 40 GeV/c mixed proton/pion beam on copper, silver and lead targets in the angular range 30-135°

    Science.gov (United States)

    Agosteo, S.; Birattari, C.; Dimovasili, E.; Foglio Para, A.; Silari, M.; Ulrici, L.; Vincke, H.

    2005-02-01

    The neutron emission from 50 mm thick copper, silver and lead targets bombarded by a mixed proton/pion beam with momentum of 40 GeV/c were measured at the CERN Super Proton Synchrotron. The neutron yield and spectral fluence per incident particle on target were measured with an extended range Bonner sphere spectrometer in the angular range 30-135° with respect to the beam direction. Monte Carlo simulations with the FLUKA code were performed to provide a priori information for the unfolding of the experimental data. The spectral fluences show two peaks, an isotropic evaporation component centred at 3 MeV and a high-energy peak sitting around 100-150 MeV. The experimental neutron yields are given in four energy bins: <100 keV, 0.1-20 MeV, 20-500 MeV and 0.5-2 GeV. The total yields show a systematic discrepancy of 30-50%, with a peak of 70% at the largest angles, with respect to the results of the Monte Carlo simulations, which it is believed to be mainly due to uncertainties in the beam normalization factor. Analytic expressions are given for the variation of the integral yield as a function of emission angle and of target mass number.

  2. Neutronics analysis of the Laboratory Microfusion Facility

    International Nuclear Information System (INIS)

    Tobin, M.T.; Singh, M.S.; Meier, W.R.

    1988-01-01

    The radiological safety hazards of the experimental area (EA) for the proposed Inertial Confinement Fusion (ICF) Laboratory Microfusion Facility (LMF) have been examined. The EA includes those structures required to establish the proper pre-shot environment, point the beams, contain the pellet yield, and measure many different facets of the experiments. The radiation dose rates from neutron activation of representative target chamber materials, the laser beam tubes and the argon gas they contain, the air surrounding the chamber, and the concrete walls of the experimental area are given. Combining these results with the allowable dose rates for workers, we show how radiological considerations affect access to the inside of the target chamber and to the diagnostic platform area located outside the chamber. Waste disposal and tritium containment issues are summarized. Other neutronics issues, such as radiation damage to the final optics and neutron heating of materials placed close to the target, are also addressed. 16 refs., 2 figs., 1 tab

  3. Intracellular targeting of mercaptoundecahydrododecaborate (BSH) to malignant glioma by transferrin-PEG liposomes for boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Doi, Atsushi; Miyatake, Shin-ichi; Iida, Kyouko

    2006-01-01

    Malignant glioma is one of the most difficult tumor to control with usual therapies. In our institute, we select boron neutron capture therapy (BNCT) as an adjuvant radiation therapy after surgical resection. This therapy requires the selective delivery of high concentration of 10 B to malignant tumor tissue. In this study, we focused on a tumor-targeting 10 B delivery system (BDS) for BNCT that uses transferrin-conjugated polyethylene-glycol liposome encapsulating BSH (TF-PEG liposome-BSH) and compared 10 B uptake of the tumor among BSH, PEG liposome-BSH and TF-PEG liposome-BSH. In vitro, we analyzed 10 B concentration of the cultured human U87Δ glioma cells incubated in medium containing 20 μg 10 B/ml derived from each BDS by inductively coupled plasma atomic emission spectrometry (ICP-AES). In vivo, human U87Δ glioma-bearing nude mice were administered with each BDS (35mg 10 B/kg) intravenously. We analyzed 10 B concentration of tumor, normal brain and blood by ICP-AES. The TF-PEG liposome-BSH showed higher absolute concentration more than the other BDS. Moreover, TF-PEG liposome-BSH decreased 10 B concentration in blood and normal tissue while it maintained high 10 B concentration in tumor tissue for a couple of days. This showed the TF-PEG liposome-BSH caused the selective delivery of high concentration of 10 B to malignant tumor tissue. The TF-PEG liposome-BSH is more potent BDS for BNCT to obtain absolute high 10 B concentration and good contrast between tumor and normal tissue than BSH and PEG liposome-BSH. (author)

  4. Neutron radiation field due to 6.6 MeV/amu 58Ni ions bombarding a thick Cu target

    International Nuclear Information System (INIS)

    Aleinikov, V.E.; Cherevatenko, A.P.; Clapier, F.B.; Tsovbun, V.I.

    1985-01-01

    The angular distribution of the dose equivalent rate and neutron spectra were obtained using the Bonner sphere spectrometry method. The quality factor was measured by a tissue-equivalent Rem-2 chamber at several angles. The agreement between the results of the measurements and an empirical parameterisation of the angular distribution is satisfactory. The total yield is estimated to be 1.6+-0.4x10 -3 neutrons per heavy ion. (author)

  5. The use of application-specific performance targets and engineering considerations to guide hydrogen storage materials development

    Energy Technology Data Exchange (ETDEWEB)

    Stetson, Ned T., E-mail: ned.stetson@ee.doe.gov [U.S. Department of Energy, 1000 Independence Ave., SW, EE-2H, Washington, DC 20585 (United States); Ordaz, Grace; Adams, Jesse; Randolph, Katie [U.S. Department of Energy, 1000 Independence Ave., SW, EE-2H, Washington, DC 20585 (United States); McWhorter, Scott [Savannah River National Laboratory, Aiken, SC 29808 (United States)

    2013-12-15

    Highlights: •Portable power and material handling equipment as early market technology pathways. •Engineering based system-level storage-materials requirements. •Application based targets. -- Abstract: The Hydrogen and Fuel Cells Technologies Office, carried out through the DOE Office of Energy Efficiency and Renewable Energy, maintains a broad portfolio of activities to enable the commercialization of fuel cells across a range of near, mid and long-term applications. Improved, advanced hydrogen storage technologies are seen as a critical need for successful implementation of hydrogen fuel cells in many of these applications. To guide and focus materials development efforts, the DOE develops system performance targets for the specific applications of interest, and carries out system engineering analyses to determine the system-level performance delivered when the materials are incorporated into a complete system. To meet the needs of applications, it is important to consider the system-level performance, not just the material-level properties. An overview of the DOE’s hydrogen storage efforts in developing application-specific performance targets and systems engineering to guide hydrogen storage materials identification and development is herein provided.

  6. The use of application-specific performance targets and engineering considerations to guide hydrogen storage materials development

    International Nuclear Information System (INIS)

    Stetson, Ned T.; Ordaz, Grace; Adams, Jesse; Randolph, Katie; McWhorter, Scott

    2013-01-01

    Highlights: •Portable power and material handling equipment as early market technology pathways. •Engineering based system-level storage-materials requirements. •Application based targets. -- Abstract: The Hydrogen and Fuel Cells Technologies Office, carried out through the DOE Office of Energy Efficiency and Renewable Energy, maintains a broad portfolio of activities to enable the commercialization of fuel cells across a range of near, mid and long-term applications. Improved, advanced hydrogen storage technologies are seen as a critical need for successful implementation of hydrogen fuel cells in many of these applications. To guide and focus materials development efforts, the DOE develops system performance targets for the specific applications of interest, and carries out system engineering analyses to determine the system-level performance delivered when the materials are incorporated into a complete system. To meet the needs of applications, it is important to consider the system-level performance, not just the material-level properties. An overview of the DOE’s hydrogen storage efforts in developing application-specific performance targets and systems engineering to guide hydrogen storage materials identification and development is herein provided

  7. Radiological protection considerations during the treatment of glioblastoma patients by boron neutron capture therapy at the high flux reactor in Petten, The Netherlands

    International Nuclear Information System (INIS)

    Moss, R.L.; Rassow, J.; Finke, E.; Sauerwein, W.; Stecher-Rasmussen, F.

    2001-01-01

    A clinical trial of Boron Neutron Capture Therapy (BNCT) for glioblastoma patients has been in progress at the High Flux Reactor (HFR) at Petten since October 1997. The JRC (as licence holder of the HFR) must ensure that radiological protection measures are provided. The BNCT trial is a truly European trial, whereby the treatment takes place at a facility in the Netherlands under the responsibility of clinicians from Germany and patients are treated from several European countries. Consequently, radiological protection measures satisfy both German and Dutch laws. To respect both laws, a BNCT radioprotection committee was formed under the chairmanship of an independent radioprotection expert, with members representing all disciplines in the trial. A special nuance of BNCT is that the radiation is provided by a mixed neutron/gamma beam. The radiation dose to the patient is thus a complex mix due to neutrons, gammas and neutron capture in boron, nitrogen and hydrogen, which, amongst others, need to be correctly calculated in non-commercial and validated treatment planning codes. Furthermore, due to neutron activation, measurements on the patient are taken regularly after treatment. Further investigations along these lines include dose determination using TLDs and boron distribution measurements using on-line gamma ray spectroscopy. (author)

  8. 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.

  9. Monte Carlo simulations and experimental results on neutron production in the spallation target QUINTA irradiated with 660 MeV protons

    International Nuclear Information System (INIS)

    Khushvaktov, J.H.; Yuldashev, B.S.; Adam, J.; Vrzalova, J.; Baldin, A.A.; Furman, W.I.; Gustov, S.A.; Kish, Yu.V.; Solnyshkin, A.A.; Stegailov, V.I.; Tichy, P.; Tsoupko-Sitnikov, V.M.; Tyutyunnikov, S.I.; Zavorka, L.; Svoboda, J.; Zeman, M.; Vespalec, R.; Wagner, V.

    2017-01-01

    The activation experiment was performed using the accelerated beam of the Phasotron accelerator at the Joint Institute for Nuclear Research (JINR). The natural uranium spallation target QUINTA was irradiated with protons of energy 660 MeV. Monte Carlo simulations were performed using the FLUKA and Geant4 codes. The number of leakage neutrons from the sections of the uranium target surrounded by the lead shielding and the number of leakage neutrons from the lead shield were determined. The total number of fissions in the setup QUINTA were determined. Experimental values of reaction rates for the produced nuclei in the "1"2"7I sample were obtained, and several values of the reaction rates were compared with the results of simulations by the FLUKA and Geant4 codes. The experimentally determined fluence of neutrons in the energy range of 10-200 MeV using the (n, xn) reactions in the "1"2"7I(NaI) sample was compared with the results of simulations. Possibility of transmutation of the long-lived radionuclide "1"2"9I in the QUINTA setup was estimated. [ru

  10. Neutron production from 40 GeV/c mixed proton/pion beam on copper, silver and lead targets in the angular range 30-135 degree

    CERN Document Server

    Agosteo, S; Dimovasili, E; Foglio-Para, A; Silari, M; Ulrici, L; Vincke, H

    2005-01-01

    The neutron emission from 50 mm thick copper, silver and lead targets bombarded by a mixed proton/pion beam with momentum of 40 GeV/c were measured at the CERN Super Proton Synchrotron. The neutron yield and spectral fluence per incident particle on target were measured with an extended range Bonner sphere spectrometer in the angular range 30-135 degree with respect to the beam direction. Monte Carlo simulations with the FLUKA code were performed to provide a priori information for the unfolding of the experimental data. The spectral fluences show two peaks, an isotropic evaporation component centred at 3 MeV and a high-energy peak sitting around 100-150 MeV. The experimental neutron yields are given in four energy bins: less than 100 keV, 0.1-20 MeV, 20-500 MeV and 0.5-2 GeV. The total yields show a systematic discrepancy of 30-50%, with a peak of 70% at the largest angles, with respect to the results of the Monte Carlo simulations, which it is believed to be mainly due to uncertainties in the beam normaliza...

  11. 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...

  12. Neutron therapy

    International Nuclear Information System (INIS)

    Riesler, Rudi

    1995-01-01

    Standard radiotherapy uses Xrays or electrons which have low LET (linear energy transfer); in contrast, particles such as neutrons with high LET have different radiobiological responses. In the late 1960s, clinical trials by Mary Catterall at the Hammersmith Hospital in London indicated that fast neutron radiation had clinical advantages for certain malignant tumours. Following these early clinical trials, several cyclotron facilities were built in the 1980s for fast neutron therapy, for example at the University of Washington, Seattle, and at UCLA. Most of these newer machines use extracted cyclotron proton beams in the range 42 to 66 MeV with beam intensities of 15 to 60 microamps. The proton beams are transported to dedicated therapy rooms, where neutrons are produced from beryllium targets. Second-generation clinical trials showed that accurate neutron beam delivery to the tumour site is more critical than for photon therapy. In order to achieve precise beam geometries, the extracted proton beams have to be transported through a gantry which can rotate around the patient and deliver beams from any angle; also the neutron beam outline (''field shape'') must be adjusted to extremely irregular shapes using a flexible collimation system. A therapy procedure has to be appropriately organized, with physicians, radiotherapists, nurses, medical physicists and other staff in attendance; other specialized equipment, such as CT or MRI scanners and radiation simulators must be made available. Neutron therapy is usually performed only in radiation oncology departments of major medical centres

  13. Neutron monitoring for radiological protection

    International Nuclear Information System (INIS)

    Gibson, J.A.B.

    1985-01-01

    Neutron monitoring is a subject of increasing general interest and considerable attention is being paid to the development of improved techniques and methods for neutron monitoring. The Agency, therefore, considered it important to prepare a guide on the subject of neutron monitoring for radiation protection purposes. The present Manual is intended for those persons or authorities in Member States, particularly developing countries, who are responsible for the organization of neutron monitoring programmes and practical neutron monitoring. This Manual consequently, deals with topics such as neutron dosimetry, sources of neutrons and neutron detection as well as field instruments and operational systems used in this context

  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. Genetic modification of hematopoietic cells using retroviral and lentiviral vectors: safety considerations for vector design and delivery into target cells.

    Science.gov (United States)

    Dropulic, Boro

    2005-07-01

    The recent development of leukemia in three patients following retroviral vector gene transfer in hematopoietic stem cells, resulting in the death of one patient, has raised safety concerns for the use of integrating gene transfer vectors for human gene therapy. This review discusses these serious adverse events from the perspective of whether restrictions on vector design and vector-modified target cells are warranted at this time. A case is made against presently establishing specific restrictions for vector design and transduced cells; rather, their safety should be ascertained by empiric evaluation in appropriate preclinical models on a case-by-case basis. Such preclinical data, coupled with proper informed patient consent and a risk-benefit ratio analysis, provide the best available prospective evaluation of gene transfer vectors prior to their translation into the clinic.

  16. Practical consideration in the selection of X-ray fluorescence tube targets for analysis of geological materials

    International Nuclear Information System (INIS)

    Attawiya, M.Y.; El-Behay, A.Z.; Khattab, F.M.

    1985-01-01

    Four X-ray fluorescence tubes with different targets (Cr, W, Mo and Rh) were compared for their suitability to analyze twelve of the most common major and trace elements in some geological samples. The major elements and Si, Al, Ca, K, Ti, and S. All elements having wavelengths higher than that of the iron K-absorption edge, gave significantly higher intensities of their characteristic fluorescence radiations when using a Cr-anode tube compared to W, Mo and Rh anode tubes. However, for the light elements (Si and Al) the Rh-anode tube of equal efficiency as the Cr-anode tube. The highest Ka-line intensity of Fe was obtained by the W-anode tube. The lowest detection limits (highest sensitivity) for the trace elements Rb, Sr, Zr, and Nb are obtained using both the Mo and Rh tubes. (author)

  17. Patient-Targeted Googling by New Zealand Mental Health Professionals: A New Field of Ethical Consideration in the Internet Age.

    Science.gov (United States)

    Thabrew, Hiran; Sawyer, Adam; Eischenberg, Christiane

    2018-01-29

    Patient-targeted Googling (PTG) describes the searching on the Internet by healthcare professionals for information about patients with or without their knowledge. Little research has been conducted into PTG internationally. PTG can have particular ethical implications within the field of mental health. This study was undertaken to identify the extent of PTG by New Zealand mental healthcare professionals and needs for further guidance regarding this issue. All (1,850) psychiatrists, clinical psychologists, and psychotherapists working in New Zealand were electronically surveyed about their experience of PTG and knowledge about the associated practice of therapist-targeted Googling (TTG) using a questionnaire that had previously been developed with a German sample. Due to ethics and advertising restrictions, only one indirect approach was made to potential participants. Eighty-eight clinicians (5%) responded to the survey invitation. More than half (53.4%, N = 47) of respondents reportedly being engaged in PTG, but only a minority (10.3%, N = 9) had ever received any education about the subject. Reasons for undertaking PTG included facilitating the therapeutic process, information being in the public domain, and mitigating risks. Reasons against undertaking PTG included impairment of therapeutic relationship, unethical invasion of privacy, and concerns regarding the accuracy and clinical relevance of online information. Two-thirds of participants reported being the subject of TTG. New Zealand psychiatrists, clinical psychologists, and psychotherapists are engaging in PTG with limited education and professional guidance. Further discussion and research are required, and so, PTG is undertaken in a manner that is safe and useful for patients and health practitioners.

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

    OpenAIRE

    McClure, Jennifer B; 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-cente...

  19. Formulation and In-vivo Pharmacokinetic Consideration of Intranasal Microemulsion and Mucoadhesive Microemulsion of Rivastigmine for Brain Targeting.

    Science.gov (United States)

    Shah, Brijesh; Khunt, Dignesh; Misra, Manju; Padh, Harish

    2018-01-02

    Presence of tight junctions in blood brain barrier (BBB) pose a major hurdle for delivery of drug and severely affects adequate therapeutic concentration to reach the brain. In present work, we have selected Rivastigmine hydrogen tartrate (RHT), a reversible cholinesterase inhibitor, which exhibits extensive first-pass metabolism, resulting in limited absolute bioavailability (36%). RHT shows extremely low aqueous solubility and poor penetration, resulting in inadequate concentration reaching the brain, thus necessitating frequent oral dosing. To overcome these problems of RHT, microemulsion (ME) and mucoadhesive microemulsion (MME) of RHT were formulated for brain targeting via intranasal delivery route and compared on the basis of in vivo pharmacokinetics. ME and MME formulations containing RHT were developed by water titration method. Characterization of ME and MME was done for various physicochemical parameters, nasal spray pattern, and in vivo pharmacokinetics quantitatively and qualitatively (gamma scintigraphy studies). The developed ME and MME were transparent having globule size approximately in the range of 53-55 nm. Pharmacokinetic studies showed higher values for C max and DTP for intranasal RHT: CH-ME over RHT-ME, thus indicating the effect of chitosan in modulating tight junctions, thereby enhanced paracellular transport of RHT. Gamma scintigraphy and in vivo pharmacokinetic study suggested enhanced RHT concentration, upon intranasal administration of RHT:CH-ME, compare with other groups administered formulations intranasally. These findings suggested the potential of non-invasive intranasal route for brain delivery, especially for therapeutics, facing challenges in oral administration.

  20. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  1. δ18O and chemical composition of Libyan Desert Glass, country rocks, and sands: New considerations on target material

    Science.gov (United States)

    Longinelli, Antonio; Sighinolfi, Giampaolo; de Michele, Vincenzo; Selmo, Enricomaria

    2011-02-01

    Oxygen isotope and chemical measurements were carried out on 25 samples of Libyan Desert Glass (LDG), 21 samples of sandstone, and 3 of sand from the same area. The δ18O of LDG samples range from 9.0‰ to 11.9‰ (Vienna Standard Mean Ocean Water [VSMOW]); some correlations between isotope data and typological features of the LDG samples are pointed out. The initial δ18O of a bulk parent material may be slightly increased by fusion due to the loss of isotopically light pore water with no isotope exchange with oxygen containing minerals. Accordingly, the δ18O of the bulk parent material of LDG may have been about 9.0 ± 1‰ (VSMOW). The measured bulk sandstone and sand samples have δ18O values ranging from 12.6‰ to 19.5‰ and are consequently ruled out as parent materials, matching the results of previous studies. However, separated quartz fractions have δ18O values compatible with the LDG values suggesting that the modern surface sand inherited quartz from the target material. This hypothesis fits previous findings of lechatelierite and baddeleyite in these materials. As the age of the parent material reported in previous studies is Pan-African, we measured the δ18O values of bulk rock and quartz from intrusives of Pan-African age and the results obtained were compatible with the LDG values. The main element abundances (Fe, Mg, Ca, K, Na) in our LDG samples conform to previous estimates; Fe, Mg, and K tend to be higher in heterogeneous samples with dark layers. The hypothesis of a low-altitude airburst involving silica-rich surface materials deriving from weathered intrusives of Pan-African age, partially melted and blown over a huge surface by supersonic winds matches the results obtained.

  2. Measurement of thick target neutron yield from the reaction (p+181 Ta) with projectiles in the range of 6-20 MeV

    Science.gov (United States)

    Paul, Sabyasachi; Sahoo, G. S.; Tripathy, S. P.; Sharma, S. C.; Joshi, D. S.; Bandyopadhyay, T.

    2018-02-01

    181Ta is a commonly used backing material for many targets in nuclear reaction studies. When the target thickness is less than the range of bombarded projectiles, the interaction via Ta(p,n) reactions in the backing can be a significant source of background. In this study, the neutron spectral yields from the reaction of protons of different energies (between 6 to 20 MeV) with a thick Ta target were determined using CR-39 detectors. The results from this study can be used as a correction factor in such situations. The parameters of registered tracks in CR-39 were analysed using an in-house image analysing program autoTRAK_n and then to derive the associated dose values. The spectral yields obtained experimentally were compared with those obtained from the theoretical calculations. The neutron yield was found to increase with increase in projectile energy mainly due to the opening of reaction channels from (p, n) to (p, 3n).

  3. 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

    1994-12-31

    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.

  4. Neutronics of pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Watanabe, Noboru

    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, poisoning, etc are discussed, aiming at a high performance pulsed spallation source

  5. Confirmatory experiments for the United States Department of Energy Accelerator Production of Tritium Program: Neutron, triton and radionuclide production by thick targets of lead and tungsten bombarded by 800 MeV protons

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Cappiello, M.; Ullmann, J.L.; Gavron, A.; King, J.D.; Laird, R.; Mayo, D.; Waters, L.; Zoeller, C.; Staples, P.

    1994-01-01

    Neutron and Triton Production by 800 MeV Protons: The experiments presented in this report were performed in support of the Accelerator Production of Tritium (APT) project at the Los Alamos Weapons Neutron Research (WNR) facility in order to provide data to benchmark and validate physics simulations used in the APT target/blanket design. An experimental apparatus was built that incorporated many of the features of the neutron source region of the 3 He target/blanket. Those features included a tungsten neutron source, flux traps, neutron moderator, lead backstop, lead multiplying annulus, neutron absorbing blanket and a combination neutron de-coupler and tritium producing gas ( 3 He). The experiments were performed in two separate proton irradiations each with approximately 100 nA-hr of 800 MeV protons. The first irradiation was made with a small neutron moderating blanket, allowing the authors to measure tritium production in the 3 He gas by sampling, and counting the amount of tritium. The second irradiation was performed with a large neutron moderating blanket (light water with a 1% manganese sulfate solution) that allowed them to measure both the tritium production in the central region and the total neutron production. The authors did this by sampling and counting the tritium produced and by measuring the activation of the manganese solution. Results of the three tritium production measurements show large disagreements with each other and therefore with the values predicted using the LAHET-MCNP code system. The source of the discrepancies may lie with the sampling system or adsorption on the tungsten surfaces. The authors discuss tests that may resolve that issue. The data for the total neutron production measurement is much more consistent. Those results show excellent agreement between calculation and experiment

  6. Radiation transport analyses in support of the SNS Target Station Neutron Beam Line Shutters Title I Design

    International Nuclear Information System (INIS)

    Miller, T.M.; Pevey, R.E.; Lillie, R.A.; Johnson, J.O.

    2000-01-01

    A detailed radiation transport analysis of the Spallation Neutron Source (SNS) shutters is important for the construction of the SNS because of its impact on conventional facility design, normal operation of the facility, and maintenance operations. Thus far the analysis of the SNS shutter travel gaps has been completed. This analysis was performed using coupled Monte Carlo and multi-dimensional discrete ordinates calculations

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

    Czech Academy of Sciences Publication Activity Database

    Závorka, L.; Adam, Jindřich; Baldin, A. A.; Čaloun, Pavel; Chilap, V. V.; Furman, W.; Kadykov, M. G.; Khushvaktov, J.; Pronskikh, V. S.; Solnyshkin, A. A.; Sotnikov, V.; Stegailov, V. I.; Suchopár, Martin; Tsoupko-Sitnikov, V. M.; Tyutyunnikov, S. I.; Voronko, V.; Vrzalová, Jitka

    2015-01-01

    Roč. 349, APR (2015), s. 31-38 ISSN 0168-583X R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : ADS * spent nuclear fuel * transmutation reaction * spallation neutrons Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 1.389, year: 2015

  8. Subcellular targets of mercaptoborate (BSH), a carrier of 10B for neutron capture therapy (BNCT) of brain tumors

    Czech Academy of Sciences Publication Activity Database

    Mareš, Vladislav; Krajčí, D.; Lisá, Věra

    2003-01-01

    Roč. 52, č. 5 (2003), s. 629-635 ISSN 0862-8408 R&D Projects: GA MPO FD-K/048 Institutional research plan: CEZ:AV0Z5011922 Keywords : thermal neutrons * brain tumors * sodium borocaptate Subject RIV: FD - Oncology ; Hematology Impact factor: 0.939, year: 2003

  9. Neutrons produced in thick targets of Be, {sup 238}U and C by means of 100 MeV/A deutons and 95 MeV/A {sup 36}Ar. Dose rate due to uranium activation; Neutrons produits dans des cibles epaisses de Be et {sup 238}U par des deutons de 100 MeV/A et de C par des {sup 36}Ar de 95 MeV/A. Debit de dose resultant de l`activation de l`uranium

    Energy Technology Data Exchange (ETDEWEB)

    Pauwels, N.; Proust, J.; Clapier, F.; Gara, P.; Mirea, M.; Obert, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Granier, T.; Belier, G.; Ethvignot, T. [CEA, Service de Physique Nucleaire, 91 - Bruyeres-le-Chatel (France)

    1998-12-01

    This study presents the results of two experiments, one lead in GANIL facilities and the other at Saturn National Laboratory. Both aim at neutron production. The energy spectra of neutrons are given for different targets and ion beams. The efficiency of deuteron beams in term of neutron production is reinforced. The neutron flux appears to be higher in any forward direction when using a beryllium target. In order to optimize shielding the neutron attenuation length in 15 cm thick concrete slab is revalued. (A.C.) 13 refs.

  10. 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.

  11. High energy neutron source for materials research and development

    International Nuclear Information System (INIS)

    Odera, M.

    1989-01-01

    Requirements for neutron source for nuclear materials research are reviewed and ESNIT, Energy Selective Neutron Irradiation Test facility proposed by JAERI is discussed. Its principal aims of a wide neutron energy tunability and spectra peaking at each energy to enable characterization of material damage process are demanding but attractive goals which deserve detailed study. It is also to be noted that the requirements make a difference in facility design from those of FMIT, IFMIF and other high energy intense neutron sources built or planned to date. Areas of technologies to be addressed to realize the ESNIT facility are defined and discussed. In order to get neutron source having desired spectral characteristics keeping moderate intensity, projectile and target combinations must be examined including experimentation if necessary. It is also desired to minimize change of flux density and energy spectrum according to location inside irradiation chamber. Extended target or multiple targets configuration might be a solution as well as specimen rotation and choice of combination of projectile and target which has minimum velocity of the center of mass. Though relevant accelerator technology exists, it is to be stressed that considerable efforts must be paid, especially in the area of target and irradiation devices to get ESNIT goal. Design considerations to allow hands-on maintenance and future upgrading possibility are important either, in order to exploit the facility fully for nuclear materials research and development. (author)

  12. Intense fusion neutron sources

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 10 15 -10 21 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 10 20 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.

  13. 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.

  14. Radiation effects in materials for accelerator-driven neutron technologies. Revision

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Lin, C.; Sommer, W.F.

    1997-01-01

    Accelerator-driven neutron technologies use spallation neutron sources (SNS's) in which high-energy protons bombard a heavy-element target and spallation neutrons are produced. The materials exposed to the most damaging radiation environments in an SNS are those in the path of the incident proton beam. This includes target and window materials. These materials will experience damage from the incident protons and the spallation neutrons. In addition, some materials will be damaged by the spallation neutrons alone. The principal materials of interest for SNS's are discussed elsewhere. The target should consist of one or more heavy elements, so as to increase the number of neutrons produced per incident proton. A liquid metal target (e.g., Pb, Bi, Pb-Bi, Pb-Mg, and Hg) has the advantage of eliminating the effects of radiation damage on the target material itself, but concerns over corrosion problems and the influence of transmutants remain. The major solid targets in operating SNS's and under consideration for the 1-5 MW SNS's are W, U, and Pb. Tungsten is the target material at LANSCE, and is the projected target material for an upgraded LANSCE target that is presently being designed. It is also the projected target material for the tritium producing SNS under design at LANL. In this paper, the authors present the results of spallation radiation damage calculations (displacement and He production) for tungsten

  15. 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)

  16. 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.

  17. 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

  18. 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

    International Nuclear Information System (INIS)

    Adam, J.; Baldin, A.A.; Chilap, V.

    2014-01-01

    Experiments with a 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 129 I, 232 Th, 233 U, 235 U, nat U, 237 Np, 238 Pu, 239 Pu and 241 Am radioactive samples were installed on the surface of the QUINTA set-up and irradiated with secondary neutrons. The neutron flux through the RA samples was monitored by Al foils. The reaction rates of 27 Al(n, y 1 ) 24 Na, 27 Al(n, y 2 ) 22 Na and 27 Al(n, y 3 ) 7 Be reactions with the effective threshold energies of 5, 27 and 119 MeV were measured at both 4- 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 energy of 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 to 8 GeV was found from the ratios of the average neutron fluxes. The reaction rates and the average neutron fluxes were calculated with MCNPX2.7 and MARS15 codes.

  19. Cylindrical neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo [Hercules, CA

    2008-04-22

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  20. Fast Neutrons - LET Distributions and the Response of Mammalian Cells

    Energy Technology Data Exchange (ETDEWEB)

    Bewley, D. K. [Medical Research Council Cyclotron Unit, Hammersmith Hospital, London (United Kingdom)

    1968-03-15

    Distributions of stopping power (LET) are given for four beams of fast neutrons, namely, neutrons of 14.6 MeV, neutrons produced by bombarding a thick beryllium target with 15 MeV deuterons, neutrons of 3 MeV, and fast neutrons produced by bombardment of a {sup 235}U converter plate with thermal neutrons. The track average LET is correlated with mean neutron energy, but the dose average is approximately constant. However, neither of these types of average is expected to have much relevance to radiobiology. Further, specification of a ''biologically effective LET'' depends on the biological test used, and is not solely a function of the radiation quality. An attempt has been made to calculate the response of T.I. kidney cells in tissue culture to these four beams of neutrons, based on their response to charged particles using the track-segment method. The calculated RBE's of the neutron beams are lower than the observed values and the calculated values of the oxygen enhancement ratio are higher. These differences seem too great to be explained by errors in dosimetry and in the calculated LET spectra. The suggestion is made that LET is not an adequate criterion of radiation quality, and that the discrepancies may be explained by more detailed consideration of the part played by delta rays and by heavy recoil tracks of short range. (author)

  1. Nanosecond neutron generator

    International Nuclear Information System (INIS)

    Lobov, S.I.; Pavlovskaya, N.G.; Pukhov, S.P.

    1991-01-01

    High-voltage nanosecond neutron generator for obtaining neutrons in D-T reaction is described. Yield of 6x10 6 neutron/pulse was generated in a sealed gas-filled diode with a target on the cathode by accelerating pulse voltage of approximately 0.5 MV and length at half-height of 0.5 ns and deuterium pressure of 6x10 -2 Torr. Ways of increasing neutron yield and possibilities of creating generators of nanosecond neutron pulses with great service life are considered

  2. Influence of differentiation of potential parameters for each excited level of the target nucleus on neutron inelastic cross section calculations

    International Nuclear Information System (INIS)

    Cabezas, R.; Lubian, J.; Moreno, E.

    1992-01-01

    In this paper scattering of neutron in medium mass nuclei (48 < a < 64) at low energies (1-5 Mev) is analyzed. The Hauser-Feshbach-Moldauer formalism and the coupled channel method is used in a combined way. In both cases, the deformed optical potential in the frame of the harmonic vibrational models is considered of integral and total cross section and angular distribution enphasized. It's shown that the use of different set parameters has a mose influence at low energies and represented a contribution of 10% of the calculated cross section with the same potential

  3. Transmutation of 239Pu and other nuclides using spallation neutrons produced by relativistic protons reacting with massive U- and Pb- targets

    International Nuclear Information System (INIS)

    Adam, J.; Balabekyan, A.; Bamblevskij, V.P.

    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 of High Energies (JINR, Dubna). Spallation neutrons were produced by relativistic protons with energies in the range of 0.5 GeV ≤ E(p) ≤ 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 aluminium 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 proton beam of 1 GeV onto a Pb-target as used here, one can transmute in one gram samples of the isotope within one month about 3 mg 129 I, 21 mg 237 Np, 3.3 mg 238 U, and 200 mg 239 Pu under the same geometrical conditions. Our observations show, that the transmutation ability of our system increases linearly with the proton energy within the energy interval studied

  4. Neutronic and thermal-hydraulic analysis of a device for irradiation of LEU UAlx-Al targets for 99Mo production in the IEA-R1 reactor

    International Nuclear Information System (INIS)

    Nishiyama, Pedro Julio Batista de Oliveira

    2012-01-01

    Technetium-99m ( 99m Tc), the product of radioactive decay of molybdenum-99 ( Mo), is one of the most widely used radioisotope in nuclear medicine, covering approximately 80% of all radiodiagnosis procedures in the world. Nowadays, Brazil requires an amount of about 450 Ci of 99 Mo per week. Due to the crisis and the shortage of 99 Mo supply chain that has been observed on the world since 2008, IPEN/CNEN-SP decided to develop a project to produce 99 Mo through fission of uranium-235. The objective of this dissertation was the development of neutronic and thermal-hydraulic calculations to evaluate the operational safety of a device for 99 Mo production to be irradiated in the IEA-Rl reactor core at 5 MW. In this device will be placed ten targets of UAl x -Al dispersion fuel with low enriched uranium (LEU) and density of 2.889 gU/cm 3 . For the neutronic calculations were utilized the computer codes HAMMER-TECHNION and CITATION and the maximum temperatures reached in the targets were calculated with the code MTRCR-IEA-R1. The analysis demonstrated that the device irradiation will occur without adverse consequences to the operation of the reactor. The total amount of 99 Mo was calculated with the program SCALE and considering that the time needed for the chemical processing and recovering of the 99 Mo will be five days after the irradiation, we have that the 99 Mo activity available for distribution will be 176 Ci for 3 days of irradiation, 236 Ci for 5 days of irradiation and 272 Ci for 7 days of targets irradiation. (author)'

  5. Radiation effects in materials for accelerator-driven neutron technologies

    International Nuclear Information System (INIS)

    Wechsler, M.S.; Lin, C.; Sommer, W.F.; Daemen, L.L.; Ferguson, P.D.

    1997-01-01

    The materials exposed to the most damaging radiation environments in an SNS (spallation neutron source) are those in the path of the incident proton beam. This includes target and window materials. These materials will experience damage from the incident protons and the spallation neutrons. The major solid targets in operating SNS's and under consideration for the 1--5 MW SNS's are W, U, and Pb. Tungsten is the target material at LANSCE, and is the project target material for an upgraded LANSCE target that is presently being designed. It is also the projected target material for the tritium producing SNS under design at LANL. In this paper, the authors present the results of spallation radiation damage calculations (displacement and He production) for tungsten

  6. Pulsed neutron sources for epithermal neutrons

    International Nuclear Information System (INIS)

    Windsor, C.G.

    1978-01-01

    It is shown how accelerator based neutron sources, giving a fast neutron pulse of short duration compared to the neutron moderation time, promise to open up a new field of epithermal neutron scattering. The three principal methods of fast neutron production: electrons, protons and fission boosters will be compared. Pulsed reactors are less suitable for epithermal neutrons and will only be briefly mentioned. The design principle of the target producing fast neutrons, the moderator and reflector to slow them down to epithermal energies, and the cell with its beam tubes and shielding will all be described with examples taken from the new Harwell electron linac to be commissioned in 1978. A general comparison of pulsed neutron performance with reactors is fraught with difficulties but has been attempted. Calculation of the new pulsed source fluxes and pulse widths is now being performed but we have taken the practical course of basing all comparisons on extrapolations from measurements on the old 1958 Harwell electron linac. Comparisons for time-of-flight and crystal monochromator experiments show reactors to be at their best at long wavelengths, at coarse resolution, and for experiments needing a specific incident wavelength. Even existing pulsed sources are shown to compete with the high flux reactors in experiments where the hot neutron flux and the time-of-flight methods can be best exploited. The sources under construction can open a new field of inelastic neutron scattering based on energy transfer up to an electron volt and beyond

  7. 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

  8. Synthesis of o-carboranylmethyl ethers of steroids as potential target substrates for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Schneiderova, L.; Gruener, B.; Strouf, O.; Kimlova, I.

    1992-01-01

    o-carboranylmethyl ethers of steroids were synthesized by insertion of steroidal 2-propynyloxy derivatives into 6,9-bis(acetonitrile)decarborane. This reaction provided compounds with an estrane and androstane skeleton, potentially useful in boron neutron capture therapy of hormone-sensitive forms of cancer: 17β-o-carboranylmethyl ether of estradiol IXb (yield 14%) and 3β- and 17β-carboranylmethyl ethers of androstenediol Vb and VIIb (yield 12% and 13%, respectively). Jones oxidation gave the carboranyl derivative of androsten-17-one VIb in 75% yield. As shown by a study of insertion of 3β-(2-propynyloxy)cholest-5-ene (IVa), the low yields of the insertion reaction cannot be increased by change in the reaction conditions. The relative binding affinity of compound IXb to the estrogen receptor from rat uterine and human breast tumor cytosol was 3.0 and 0.29%, respectively, of that of estradiol. (author) 2 figs., 2 tabs., 20 refs

  9. Neutron-rich nuclei produced at zero degrees in damped collisions induced by a beam of 18O on a 238U target

    Science.gov (United States)

    Stefan, I.; Fornal, B.; Leoni, S.; Azaiez, F.; Portail, C.; Thomas, J. C.; Karpov, A. V.; Ackermann, D.; Bednarczyk, P.; Blumenfeld, Y.; Calinescu, S.; Chbihi, A.; Ciemala, M.; Cieplicka-Oryńczak, N.; Crespi, F. C. L.; Franchoo, S.; Hammache, F.; Iskra, Ł. W.; Jacquot, B.; Janssens, R. V. F.; Kamalou, O.; Lauritsen, T.; Lewitowicz, M.; Olivier, L.; Lukyanov, S. M.; Maccormick, M.; Maj, A.; Marini, P.; Matea, I.; Naumenko, M. A.; de Oliveira Santos, F.; Petrone, C.; Penionzhkevich, Yu. E.; Rotaru, F.; Savajols, H.; Sorlin, O.; Stanoiu, M.; Szpak, B.; Tarasov, O. B.; Verney, D.

    2018-04-01

    Cross sections and corresponding momentum distributions have been measured for the first time at zero degrees for the exotic nuclei obtained from a beam of 18O at 8.5 MeV/A impinging on a 1 mg/cm2238U target. Sizable cross sections were found for the production of exotic species arising from the neutron transfer and proton removal from the projectile. Comparisons of experimental results with calculations based on deep-inelastic reaction models, taking into account the particle evaporation process, indicate that zero degree is a scattering angle at which the differential reaction cross section for production of exotic nuclei is at its maximum. This result is important in view of the new generation of zero degrees spectrometers under construction, such as the S3 separator at GANIL, for example.

  10. Performance of the multiple target He/PbI sub 2 aerosol jet system for mass separation of neutron-deficient actinide isotopes

    CERN Document Server

    Ichikawa, S; Asai, M; Haba, H; Sakama, M; Kojima, Y; Shibata, M; Nagame, Y; Oura, Y; Kawade, K

    2002-01-01

    A multiple target He/PbI sub 2 aerosol jet system coupled with a thermal ion source was installed in the isotope separator on line (JAERI-ISOL) at the JAERI tandem accelerator facility. The neutron-deficient americium and curium isotopes produced in the sup 2 sup 3 sup 3 sup , sup 2 sup 3 sup 5 U( sup 6 Li, xn) and sup 2 sup 3 sup 7 Np( sup 6 Li, xn) reactions were successfully mass-separated and the overall efficiency including the ionization of Am atoms was evaluated to be 0.3-0.4%. The identification of a new isotope sup 2 sup 3 sup 7 Cm with the present system is reported.

  11. Neutron and photon measurements through concrete from a 15 GeV electron beam on a target-comparison with models and calculations. [Intermediate energy source term, Monte Carlo code

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, T M [Stanford Linear Accelerator Center, CA (USA)

    1979-02-15

    Measurements of neutron and photon dose equivalents from a 15 GeV electron beam striking an iron target inside a scale model of a PEP IR hall are described, and compared with analytic-empirical calculations and with the Monte Carlo code, MORSE. The MORSE code is able to predict both absolute neutron and photon dose equivalents for geometries where the shield is relatively thin, but fails as the shield thickness is increased. An intermediate energy source term is postulated for analytic-empirical neutron shielding calculations to go along with the giant resonance and high energy terms, and a new source term due to neutron capture is postulated for analytic-empirical photon shielding calculations. The source strengths for each energy source term, and each type, are given from analysis of the measurements.

  12. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Agosteo, S.; Nakamura, T.; Silari, M. E-mail: marco.silari@cern.ch; 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 deg. . 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.

  14. 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.

  15. High energy neutron generator

    International Nuclear Information System (INIS)

    Barjon, R.; Breynat, G.

    1987-01-01

    This patent describes a generator of fast neutrons only slightly contaminated by neutrons of energy less than 15 MeV, comprising a source of charged particles of energy equal to at least 15 MeV, a target made of lithium deuteride, and means for cooling the target. The target comprises at least two elements placed in series in the path of the charged particles and separated from each other, the thickness of each of the elements being selected as a function of the average energy of the charged particles emitted from the source and the energy of the fast neutrons to be generated such that neutrons of energy equal to at least 15 MeV are emitted in the forward direction in response to the bombardment of the target from behind by the charged particles. The target cooling means comprises means for circulating between and around the elements a gas which does not chemically react with lithium deuteride

  16. Source characterization of Purnima Neutron Generator (PNG)

    International Nuclear Information System (INIS)

    Bishnoi, Saroj; Patel, T.; Paul, Ram K.; Sarkar, P.S.; Adhikari, P.S.; Sinha, Amar

    2011-01-01

    The use of 14.1 MeV neutron generators for the applications such as elemental analysis, Accelerated Driven System (ADS) study, fast neutron radiography requires the characterization of neutron source i.e neutron yield (emission rate in n/sec), neutron dose, beam spot size and energy spectrum. In this paper, a series of experiments carried out to characterize this neutron source. The neutron source has been quantified with neutron emission rate, neutron dose at various source strength and beam spot size at target position

  17. Production of 14 MeV neutrons from D-D neutron generators

    International Nuclear Information System (INIS)

    Cecil, F.E.; Nieschmidt, E.B.

    1986-01-01

    The production of 14 MeV neutrons from a D-D neutron generator resulting from tritium buildup from the d(d,p)t reaction in the target is discussed. The effect of the 14 MeV neutrons on fast neutron activation analysis with D-D neutron generators is evaluated. (orig.)

  18. Temperature effects on the mechanical properties of candidate SNS target container materials after proton and neutron irradiation

    International Nuclear Information System (INIS)

    Byun, T.S.; Farrell, K.; Lee, E.H.; Mansur, L.K.; Maloy, S.A.; James, M.R.; Johnson, W.R.

    2002-01-01

    This report presents the tensile properties of EC316LN austenitic stainless steel and 9Cr-2WVTa ferritic/martensitic steel after 800 MeV proton and spallation neutron irradiation to doses in the range 0.54-2.53 dpa at 30-100 deg. C. Tensile testing was performed at room temperature (20 deg. C) and 164 deg. C. The EC316LN stainless steel maintained notable strain-hardening capability after irradiation, while the 9Cr-2WVTa ferritic/martensitic steel posted negative hardening in the engineering stress-strain curves. In the EC316LN stainless steel, increasing the test temperature from 20 to 164 deg. C decreased the strength by 13-18% and the ductility by 8-36%. The effect of test temperature for the 9Cr-2WVTa ferritic/martensitic steel was less significant than for the EC316LN stainless steel. In addition, strain-hardening behaviors were analyzed for EC316LN and 316L stainless steels. The strain-hardening rate of the 316 stainless steels was largely dependent on test temperature. A calculation using reduction of area measurements and stress-strain data predicted positive strain hardening during plastic instability

  19. Transferrin-loaded nido-carborane liposomes. Synthesis and intracellular targeting to solid tumors for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Nakamura, Hiroyuki; Miyajima, Yusuke; Kuwata, Yasuhiro; Maruyama, Kazuo; Masunaga, Shinichiro; Ono, Koji

    2006-01-01

    The boron ion cluster lipids, as a double-tailed boron lipid synthesized from heptadecanol, formed stable liposomes at 25% molar ratio toward DSPC with cholesterol. Transferrin was able to be introduced on the surface of boron liposomes (Tf-PEG-CL liposomes) by the coupling of transferrin to the PEG-CO 2 H moieties of PEG-CL liposomes. The biodistribution of Tf-PEG-CL liposomes showed that Tf-PEG-CL liposomes accumulated in tumor tissues and stayed there for a sufficiently long time to increase tumor:blood concentration ratio. A 10 B concentration of 22 ppm in tumor tissues was achieved by the injection of Tf-PEG-CL liposome at 7.2 mg/kg body weight 10 B in tumor-bearing mice. After neutron irradiation, the average survival rate of mice not treated with Tf-PEG-CL liposomes was 21 days, whereas that of the treated mice was 31 days. Longer survival rates were observed in the mice treated with Tf-PEG-CL liposomes; one of them even survived for 52 days after BNCT. (author)

  20. Compact neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  1. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  2. Remarks on some rock neutron parameters

    International Nuclear Information System (INIS)

    Czubek, J.A.

    1984-01-01

    A method to calculate the thermal neutron parameters of rocks is given in the paper. It is based on a proper energy averaging of cross-sections for all rock matrix and rock saturating liquid constituents. The diffusion lengths in different lithologies in function of the variable rock porosity have been calculated. An influence of the thermal neutron spectrum on the shape of the porosity calibration curves for the dual spacing neutron method is shown. Magmatic rocks as a possible source of geothermal energy are now becoming a target of neutron loggings for the porosity determination. Here the knowledge of the slowing-down lengths is of great importance in the problem of the estimation of the calibration curves. A semi-analytical approach to get this parameter is given in the paper. It was found, as far as concerns the slowing-down of fast neutrons, that all magmatic rocks behave as sandstone with, however, different content of bound water in the rock matrix and different rock matrix density. Some neutron methods are based on the detection of epithermal neutrons. For theoretical considerations it is important to know the physical meaning of the registered signal. From the discussion of experimental data reported in the literature it seems that it is the slowing-down density that is the physical quantity being measured. This conclusion has a very important practical implication - the porosity calibration curves depend upon the slowing-down length alone and are independent of the slowing-down cross-section for epithermal neutrons

  3. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  4. Temperature Effects on the Mechanical Properties of Candidate SNS Target Container Materials after Proton and Neutron Irradiation; TOPICAL

    International Nuclear Information System (INIS)

    Byun, T.S.

    2001-01-01

    This report presents the tensile properties of EC316LN austenitic stainless steel and 9Cr-2WVTa ferritic/martensitic steel after 800 MeV proton and spallation neutron irradiation to doses in the range 0.54 to 2.53 dpa. Irradiation temperatures were in the range 30 to 100 C. Tensile testing was performed at room temperature (20 C) and 164 C to study the effects of test temperature on the tensile properties. Test materials displayed significant radiation-induced hardening and loss of ductility due to irradiation. The EC316LN stainless steel maintained notable strain-hardening capability after irradiation, while the 9Cr-2WVTa ferritic/martensitic steel posted negative strain hardening. In the EC316LN stainless steel, increasing the test temperature from 20 C to 164 C decreased the strength by 13 to 18% and the ductility by 8 to 36%. The tensile data for the EC316LN stainless steel irradiated in spallation conditions were in line with the values in a database for 316 stainless steels for doses up to 1 dpa irradiated in fission reactors at temperatures below 200 C. However, extra strengthening induced by helium and hydrogen contents is evident in some specimens irradiated to above about 1 dpa. The effect of test temperature for the 9Cr-2WVTa ferritic/martensitic steel was less significant than for the EC316LN stainless steel. In addition, strain-hardening behaviors were analyzed for EC316LN and 316L stainless steels. The strain-hardening rate of the 316 stainless steels was largely dependent on test temperature. It was estimated that the 316 stainless steels would retain more than 1% true stains to necking at 164 C after irradiation to 5 dpa. A calculation using reduction of area (RA) measurements and stress-strain data predicted positive strain hardening during plastic instability

  5. Recent Neutronic Optimization Studies at the SNS

    International Nuclear Information System (INIS)

    Murphy, B.D.; Ferguson, P.D.

    2002-01-01

    Recent design considerations at the Spallation Neutron Source have led to significant changes in the target station design, including changing the outer lead reflector to stainless steel and adding structural elements to aid heat transfer. In light of the design evolution, basic design decisions, including the moderator positions, were re-evaluated. With the proton beam energy of 1.0 GeV and a beam power of 2 MW, moderator positions were originally selected to optimize the performance of the upstream moderators, although some penalty was accepted in order to enhance the overall performance of the mixed coupled and decoupled moderators in the SNS target system. The work presented in this paper details sensitivity studies of selected moderator positions as a function of neutron energy. A possible change in proton beam energy, to 1.3 GeV while maintaining a beam power of 2 MW, is also studied in terms of moderator position. (authors)

  6. An electroamalgamation approach to separate 47Sc from neutron activated CaO target for use in cancer theranostics

    International Nuclear Information System (INIS)

    Chakravarty, Rubel; Chakraborty, Sudipta; Dash, Ashutosh

    2016-01-01

    Over the last few years, 47 Sc has attracted significant attention for potential use in cancer theranostics due to its favorable nuclear decay characteristics (t 1/2 = 3.35 d; average β energy, 162 keV; Eγ, 159 keV). No-carrier-added (NCA) 47 Sc can be produced via the 46 Ca(n,γ)→ 47 Sc reaction in a nuclear reactor. For this purpose, 1 mg of CaO (98 % enrichment of 46 Ca) target was irradiated for 7 d at a flux of 1 × 10 14 n.cm -2 .s -1 at the Dhruva reactor of our research centre. The irradiated target was dissolved in 5 ml of 1 M HCl inside a lead shielded facility. The resultant solution was evaporated to near dryness, reconstituted in 20 ml of 0.15 M lithium citrate solution and transferred to the electrochemical cell. The electrochemical separation involved selective amalgamation of Ca from Ca/Sc mixture into mercury-pool cathode. The influence of different experimental parameters (such as applied potential, pH of the electrolyte, time of electrolysis and amount of Ca 2+ ions in the electrolyte) on the separation process was investigated and optimized for the quantitative electroamalgamation of Ca

  7. Coupled moderator neutronics

    International Nuclear Information System (INIS)

    Russell, G.J.; Pitcher, E.J.; Ferguson, P.D.

    1995-01-01

    Optimizing the neutronic performance of a coupled-moderator system for a Long-Pulse Spallation Source is a new and challenging area for the spallation target-system designer. For optimal performance of a neutron source, it is essential to have good communication with instrument scientists to obtain proper design criteria and continued interaction with mechanical, thermal-hydraulic, and materials engineers to attain a practical design. A good comprehension of the basics of coupled-moderator neutronics will aid in the proper design of a target system for a Long-Pulse Spallation Source

  8. Neutronic and thermal-hydraulic analysis of devices for irradiation of LEU targets type of UALx-Al and U-Ni to production of 99Mo in reactor IEA-R1 and RMB

    International Nuclear Information System (INIS)

    Domingos, Douglas Borges

    2014-01-01

    In this work neutronic and thermal-hydraulic analyses were made to compare three types of targets (UAl 2 -Al, U-Ni cylindrical and U-Ni plate) used for the production of 99 Mo by fission of 235 U. Some experiments were conducted to validate the neutronic and thermal-hydraulics methodologies used in this work. For the neutronic calculations the computational programs NJOY99.0, AMPX-II and HAMMERTECHNION were used to generate the cross sections. SCALE 6.0 and CITATION computational programs were used for three-dimensional calculations of the reactor cores, fuel burning and the production of 99 Mo. The computational programs MTRCR-IEAR1 and ANSYS CFX were used to calculate the thermal and hydraulic parameters of the irradiation devices and for comparing them to limits and design criteria. First were performed neutronic and thermal-hydraulic analyzes for the reactor IEA-R1 with the targets of UAl 2 -Al (10 mini plates). Analyses have shown that the total activity obtained for 99 Mo on the mini plates does not meet the demand of Brazilian hospitals (450 Ci/week) and that no limit of thermo-hydraulic design is overtaken. Next, the same calculations were performed for the three target types in Multipurpose Brazilian Reactor (MBR). The neutronic analyzes demonstrated that the three targets meet the demand of Brazilian hospitals. The thermal hydraulic analysis shows that a minimum speed of 7 m/s for the target UAl 2 -Al, 8 m/s for the cylindrical target U-Ni and 9 m/s for the target U-Ni plate will be necessary in the irradiation device to not exceed the design limits. Were performed experiments using a test bench for validate the methodologies for the thermal-hydraulic calculation. The experiments performed to validate the neutronic calculations were made in the reactor IPEN/MB-01. All experiments were simulated with the methodologies described above and the results compared. The simulations results showed good agreement with experimental results. (author)

  9. The TRIUMF thermal neutron facility as planned for operation by 1978

    International Nuclear Information System (INIS)

    Arrott, A.S.; Templeton, T.L.; Thorson, I.M.; Blaby, R.E.; Burgerjon, J.J.

    1977-08-01

    The concepts of the thermal neutron facility have been considerably modified since they were first put forth in 1971. The move has been toward simplification. This report describes the basic vacuum tank structure, its surrounding steel shielding and the concrete structure. The vacuum tank contains a target, moderator and reflector and has ports for the extraction of thermal neutron beams. It also has capabilities for producing mesons and for irradiation of targets in the primary proton beam. The system has been designed with flexibility for modification to meet possible future demands for irradiation facilities, radiography, or pulsed operation. The targets can be easily changed, and it is planned to do this to meet the heat transfer problems as they arise on going to higher beam currents. Feasibility studies for Pb-Bi and Pb targets have been carried out. The Pb target was chosen because of safety considerations and simpler design. (author)

  10. MEGAPIE analytical support task : characterization of lead-bismuth eutectic and sodium-cooled tungsten target materials for accelerator driven systems

    International Nuclear Information System (INIS)

    Gohar, Y.

    2002-01-01

    Lead-Bismuth Eutectic and Tungsten are under consideration as target materials with high-energy protons for generating neutrons to drive actinide and fission product transmuters. A detailed characterization has been performed to study the performance of these target materials 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 impact on the target performance. The characterization has also considered high-energy deuteron particles to study the impact on the target neutronic performance. The obtained results quantify the performance of the Lead-Bismuth Eutectic and Tungsten target materials as a function of the target variables and design selections

  11. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  12. Postirradiation evaluations of capsules HANS-1 and HANS-2 irradiated in the HFIR target region in support of fuel development for the advanced neutron source

    International Nuclear Information System (INIS)

    Hofman, G.L.; Snelgrove, J.L.; Copeland, G.L.

    1995-08-01

    This report describes the design, fabrication, irradiation, and evaluation of two capsule tests containing U 3 Si 2 fuel particles in contact with aluminum. The tests were in support of fuel qualification for the Advanced Neutron Source (ANS) reactor, a high-powered research reactor that was planned for the Oak Ridge National Laboratory. At the time of these tests, the fuel consisted of U 3 Si 2 , containing highly enriched uranium dispersed in aluminum at a volume fraction of ∼0.15. The extremely high thermal flux in the target region of the High Flux Isotope Reactor provided up to 90% burnup in one 23-d cycle. Temperatures up to 450 degrees C were maintained by gamma heating. Passive SiC temperature monitors were employed. The very small specimen size allowed only microstructural examination of the fuel particles but also allowed many specimens to be tested at a range of temperatures. The determination of fission gas bubble morphology by microstructural examination has been beneficial in developing a fuel performance model that allows prediction of fuel performance under these extreme conditions. The results indicate that performance of the reference fuel would be satisfactory under the ANS conditions. In addition to U 3 Si 2 , particles of U 3 Si, UAl 2 , UAl x , and U 3 O 8 were tested

  13. Preliminary neutron shielding calculations of the electronics in the EAST BES systems focusing on neutron induced displacement damage

    Energy Technology Data Exchange (ETDEWEB)

    Náfrádi, Gábor, E-mail: nafradi@reak.bme.hu [Institute of Nuclear Techniques (NTI), Budapest University of Technology and Economics (BME), H-1111 Budapest (Hungary); Kovácsik, Ákos, E-mail: kovacsik.akos@reak.bme.hu [Institute of Nuclear Techniques (NTI), Budapest University of Technology and Economics (BME), H-1111 Budapest (Hungary); Németh, József, E-mail: nemeth.jozsef@wigner.mta.hu [Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics (Wigner RCP), Hungarian Academy of Sciences (HAS), POB 49, 1525 Budapest (Hungary); Pór, Gábor, E-mail: por@reak.bme.hu [Institute of Nuclear Techniques (NTI), Budapest University of Technology and Economics (BME), H-1111 Budapest (Hungary); Zoletnik, Sándor, E-mail: zoletnik.sandor@wigner.mta.hu [Institute for Particle and Nuclear Physics, Wigner Research Centre for Physics (Wigner RCP), Hungarian Academy of Sciences (HAS), POB 49, 1525 Budapest (Hungary)

    2016-11-15

    Monte Carlo N-Particle (MCNP) calculations were carried out to compare neutron shielding capabilities of three frequently used neutron shielding materials: polyethylene without neutron absorbers, polyethylene with boron absorbers and polyethylene with lithium absorbers, according to Non Ionizing Energy Loss (NIEL). The results of 1D shielding calculations showed that simple neutron moderating materials can provide sufficient and cheap shielding against 2.45 MeV and 14.1 MeV fusion neutrons, in terms of 1 MeV neutron equivalent flux, in silicon targets, which is the most commonly used material of electronic components. Based on these results a new shielding concept is proposed which can be taken into consideration where the reduction of displacement damage is the main goal and the free space available for shielding is limited. Based on this shielding concept detailed 3D calculations were carried out to describe the properties of the neutron shielding of the Beam Emission Spectroscopy (BES) system installed at the EAST tokamak.

  14. Neutron Research in HANARO

    International Nuclear Information System (INIS)

    Kim, Hark Rho

    2005-01-01

    HANARO (High-flux Advanced Neutron Application Reactor), which was designed and constructed by indigenous technology, is a world-class multi-purpose research reactor with a design thermal power of 30 MW, providing high neutron flux for various applications in Korea. HANARO has been operated since its first criticality in February 1995, and is now successfully utilized in such areas as neutron beam research, fuel and materials tests, radioisotopes and radiopharmaceuticals production, neutron activation analysis, and neutron transmutation doping, etc. A number of experimental facilities have been developed and installed since the beginning of reactor operation, and R and D activities for installing more facilities are actively under progress. Three flux traps in the core (CT, IR1, IR2), providing a high fast neutron flux, can be used for materials and fuel irradiation tests. They are also proper for production of high specific activity radioisotopes. Four vertical holes in the outer core region, abundant in epithermal neutrons, are used for fuel or material tests and radioisotope production. In the heavy water reflector region, 25 vertical holes with high quality thermal neutrons are located for radioisotope production, neutron activation analysis, neutron transmutation doping and cold neutron source installation. The two largest holes named NTD1 and NTD2 are for neutron transmutation doping, CNS for the cold neutron source installation, and LH for the irradiation of large targets. The high resolution powder diffractometer (HRPD) became operational in 1998, followed by the four circle diffractometer (FCD) in 1999, the residual stress instrument (RSI) in 2000, and the small angle neutron spectrometer (SANS) in 2001, respectively. HRPD and SANS became the most popular instruments these days, attracting wide range of users from academia, institutes and industries. We have made a lot of efforts during the last 10 years to develop some key components such as

  15. Two-layer targets for the D-D reaction

    International Nuclear Information System (INIS)

    Dekhtyar, M.I.; Primenko, G.I.; Strizhak, V.I.

    1980-01-01

    Neutron concentration and neutron output from twolayer loading target during deuteron beam braking in first layer of target is studied theoretically. Struggling effect on neutron output is discussed [ru

  16. Design of a target and moderator at the Los Alamos Spallation Radiation Effects Facility (LASREF) as a neutron source for fusion reactor materials development

    International Nuclear Information System (INIS)

    Ferguson, P.D.; Mueller, G.E.

    1993-01-01

    The LASREF facility is located in the beam stop area at LAMPF. The neutron spectrum is fission-like with the addition of a 3% to 5% component with E > 20 MeV. The present study evaluates the limits on geometry and material selection that will maximize the neutron flux. MCNP and LAHET were used to predict the neutron flux and energy spectrum for a variety of geometries. The problem considers 760 MeV protons incident on tungsten. The resulting neutrons are multiplied in uranium through (n,xn) reactions. Calculations show that a neutron flux greater than 10 19 n/m 2 /s is achievable. The helium to dpa ratio and the transmutation product generation are calculated. These results are compared to expectations for the proposed DEMO fusion reactor and to FFTF

  17. Studying Angular Distribution of Neutron for (p,n) Reaction from 0.5 GeV to 1.5 GeV on some Heavy Targets 238U, 206Pb, 197Au, 186W

    International Nuclear Information System (INIS)

    Nguyen Mong Giao; Tran Thanh Dung; Nguyen Thi Ai Thu; Huynh Thi Xuan Tham

    2010-08-01

    The angular distributions of neutron are calculated for a spallation reaction induced by proton energy from 0.5 GeV to 1.5 GeV on target nuclei 206 Pb, 197 Au, 238 U, 186 W. In this report, we use nuclear data of JENDL-HE with evaluated proton induced cross-sections up to 3 GeV. The obtained results have been discussed in detail. (author)

  18. Experiments on neutron-proton and neutron-electron interaction

    International Nuclear Information System (INIS)

    Koester, L.

    1975-01-01

    The paper reports on zero-energy experiments with neutrons, protons and electrons with a wavelength that is considerably longer than the particle expansion. Scattering amplitudes are measured for the reactions n + p and n + e. A neutron gravity refractometer is used. (WL/AK) [de

  19. A Bragg curve counter with an internal production target for the measurement of the double-differential cross-section of fragment production induced by neutrons at energies of tens of MeV

    International Nuclear Information System (INIS)

    Sanami, T.; Hagiwara, M.; Oishi, T.; Hosokawa, M.; Kamada, S.; Tanaka, Su.; Iwamoto, Y.; Nakashima, H.; Baba, M.

    2009-01-01

    A Bragg curve counter equipped with an internal production target was developed for the measurements of double-differential cross-sections of fragment production induced by neutrons at energies of tens of MeV. The internal target permitted a large detection solid angle and thus the registration of processes at low production rates. In this specific geometry, the detection solid angle depends on the emission angle and the range of the particle. Therefore the energy, atomic number, and angle of trajectory of the particle have to be taken into account for the determination of the solid angle. For the selection of events with tracks confined within a defined cylindrical volume around the detector axis, a segmented anode was applied. The double-differential cross-sections for neutron-induced production of lithium, beryllium, and boron fragments from a carbon target were measured at 0 deg. for 65 MeV neutrons. The results are in good agreement with theoretical calculation using PHITS code with GEM and ISOBAR model.

  20. Spherical neutron generator

    Science.gov (United States)

    Leung, Ka-Ngo

    2006-11-21

    A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.

  1. Experiment of Neutron Generation by Using Prototype D-D Neutron Generator

    International Nuclear Information System (INIS)

    Kim, In Jung; Kim, Suk Kwon; Park, Chang Su; Jung, Nam Suk; Jung, Hwa Dong; Park, Ji Young; Hwang, Yong Seok; Choi, H.D.

    2005-01-01

    Experiment of neutron generation was performed by using a prototype D-D neutron generator. The characteristics of D-D neutron generation in drive-in target was studied. The increment of neutron yield by increasing ion beam energy was investigated, too

  2. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  3. A neutron beam polarizer for study of parity violation in neutron-nucleus interactions

    International Nuclear Information System (INIS)

    Penttilae, S.I.; Bowman, J.D.; Frankle, C.M.; Seestrom, S.J.; Yen, Yi-Fen; Delheij, P.P.J.; Haase, D.G.; Postma, H.

    1994-01-01

    A dynamically-polarized proton target operating at 5 Tesla and 1 K has been built to, neutron beam for studies of parity violation in compound-nuclear resonances. Nearly 0.9 proton polarization was obtained in an electron-beam irradiated ammonia target. This was used to produce a neutron beam polarization of 0.7 at epithermal energies. The combination of the polarized proton target and the LANSCE spallation neutron source produces the most intense pulsed polarized epithermal neutron beam in the world. The neutron-beam polarizer is described and methods to determine neutron beam polarization are presented

  4. A neutron beam polarizer for study of parity violation in neutron-nucleus interactions

    International Nuclear Information System (INIS)

    Penttilae, S.I.; Bowman, J.D.; Delheij, P.P.; Frankle, C.M.; Haase, D.G.; Postma, H.; Seestrom, S.J.; Yen, Y.

    1995-01-01

    A dynamically-polarized proton target operating at 5 Tesla and 1 K has been built to polarize an epithermal neutron beam for studies of parity violation in compound-nuclear resonances. Nearly 0.9 proton polarization was obtained in an electron-beam irradiated ammonia target. This was used to produce a neutron beam polarization of 0.7 at epithermal energies. The combination of the polarized proton target and the LANSCE spallation neutron source produces the most intense pulsed polarized epithermal neutron beam in the world. The neutron-beam polarizer is described and methods to determine neutron beam polarization are presented. copyright 1995 American Institute of Physics

  5. Nuclear polarization and neutrons

    International Nuclear Information System (INIS)

    Glaettli, H.

    1985-01-01

    Different possibilities for the use of polarized nuclei in thermal neutron scattering on condensed matter are reviewed. Highly polarized nuclei are the starting point for studying dipolar magnetic order. Systematic measurement of spin-dependent scattering lengths is possible on samples with polarized nuclei. Highly polarized hydrogen should help to unravel complicated structures in chemistry and biology. The use of polarized proton targets as an energy-independent neutron polarizer in the thermal and epithermal region should be considered afresh. (author)

  6. Thermal neutron source study

    International Nuclear Information System (INIS)

    Holden, T.M.

    1983-05-01

    The value of intense neutron beams for condensed matter research is discussed with emphasis on the complementary nature of steady state and pulsed neutron sources. A large body of information on neutron sources, both existing and planned, is then summarized under four major headings: fission reactors, electron accelerators with heavy metal targets, pulsed spallation sources and 'steady state' spallation sources. Although the cost of a spallation source is expected to exceed that of a fission reactor of the same flux by a factor of two, there are significant advantages for a spallation device such as the proposed Electronuclear Materials Test Facility (EMTF)

  7. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  8. Comprehensive analysis of shielding effectiveness for HDPE, BPE and concrete as candidate materials for neutron shielding

    International Nuclear Information System (INIS)

    Dhang, Prosenjit; Verma, Rishi; Shyam, Anurag

    2015-01-01

    In the compact accelerator based DD neutron generator, the deuterium ions generated by the ion source are accelerated after the extraction and bombarded to a deuterated titanium target. The emitted neutrons have typical energy of ∼2.45MeV. Utilization of these compact accelerator based neutron generators of yield up to 10 9 neutron/second (DD) is under active consideration in many research laboratories for conducting active neutron interrogation experiments. Requirement of an adequately shielded laboratory is mandatory for the effective and safe utilization of these generators for intended applications. In this reference, we report the comprehensive analysis of shielding effectiveness for High Density Polyethylene (HDPE), Borated Polyethylene (BPE) and Concrete as candidate materials for neutron shielding. In shielding calculations, neutron induced scattering and absorption gamma dose has also been considered along with neutron dose. Contemporarily any material with higher hydrogenous concentration is best suited for neutron shielding. Choice of shielding material is also dominated by practical issues like economic viability and availability of space. Our computational analysis results reveal that utilization of BPE sheets results in minimum wall thickness requirement for attaining similar range of attenuation in neutron and gamma dose. The added advantage of using borated polyethylene is that it reduces the effect of both neutron and gamma dose by absorbing neutron and producing lithium and alpha particle. It has also been realized that for deciding upon optimum thickness determination of any shielding material, three important factors to be necessarily considered are: use factor, occupancy factor and work load factor. (author)

  9. Neutron induced radiation damage

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    1977-01-01

    We derive a general expression for the number of displaced atoms of type j caused by a primary knock-on of type i. The Kinchin-Pease model is used, but considerably generalised to allow for realistic atomic potentials. Two cases are considered in detail: the single particle problem causing a cascade and the neutron initiated problem which leads to multiple subcascades. Numerical results have been obtained for a variety of scattering laws. An important conclusion is that neutron initiated damage is much more severe than atom-initiated damage and leads to the number of displaced atoms being a factor of (A+1) 2 /4A larger than the single primary knock-on theory predicts. A is the ratio of the atomic mass to the neutron mass. The importance of this result to the theory of neutron sputtering is explained. (orig.) [de

  10. 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.

  11. Neutrons at COSY

    International Nuclear Information System (INIS)

    Filges, D.; Freiesleben, H.

    1988-05-01

    For many years neutrons were considered important both as a useful probe in nuclear physics research and as an initiator and catalyst for fission, fusion and other applications. As a result knowledge about neutrons, especially below 20 MeV, received organized world-wide attention. Research with neutrons at medium energies, say 50 MeV to several GeV, has not consistently received attention and no systematic evaluations exist. But there is a large and considerable interest today because medium energy neutrons are very important in basic science and technology. The aim of this workshop was to provide an overview of the present status and the research which should be carried out in this field in future and which kind of experiments should be performed at the COSY facility: State-of-the-art about medium energy neutron experiments and existing facilities; planned experiments; needs for experiments doing research with neutrons at COSY (detectors, accelerator requirements, time structure etc.); what will be a first experiment to measure neutrons at COSY. The interest in this workshop is documented by a large number of participants. Copies of the viewgraphs of the talks are provided. (orig./HP)

  12. Threat Assessment and Targeted Violence at Institutions of Higher Education: Implications for Policy and Practice Including Unique Considerations for Community Colleges

    Science.gov (United States)

    Bennett, Laura; Bates, Michael

    2015-01-01

    This article provides an overview of the research on targeted violence, including campus violence, and the implications for policy and practice at institutions of higher education. Unique challenges of threat assessment in the community college setting are explored, and an overview of an effective threat assessment policy and team at William…

  13. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J.

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  14. A neutron well logging system

    International Nuclear Information System (INIS)

    1980-01-01

    A pulsed neutron well logging system using a sealed off neutron generator tube is provided with a programmable digital neutron output control system. The control system monitors the target beam current and compares a function of this current with a pre-programmed control function to develop a control signal for the neutron generator. The control signal is used in a series regulator to control the average replenisher current of the neutron generator tube. The programmable digital control system of the invention also provides digital control signals as a function of time to provide ion source voltages. This arrangement may be utilized to control neutron pulses durations and repetition rates or to produce other modulated wave forms for intensity modulating the output of the neutron generator as a function of time. (Auth.)

  15. 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.

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

    International Nuclear Information System (INIS)

    Schefer, J.; Castellazzi, D.; Shea-Braun, M.

    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 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

  17. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

  18. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

  19. Use of anticoagulant rodenticides in outdoor urban areas: considerations and proposals for the protection of public health and non-target species.

    Science.gov (United States)

    Dutto, M; Di Domenico, D; Rubbiani, M

    2018-01-01

    Rodent control operations represent an important tool for the prevention and management of infestations, in outdoor environments, by synanthropic rodents (Rattus rattus and R. norvegicus), which are a source of economic and environmental damage with significant sanitary implications. Although the use of anticoagulants is safer to humans and pets compared to the use of acute poisoning substances, an intrinsic hazard of the active ingredients exists, i.e. the possible poisoning of non-target organisms (e.g., children, pets and wildlife) following exposure. The risks arising from the use of anticoagulants for rodent control operations in anthropic contexts can therefore only be mitigated by a proper selection of the active ingredient, bait formulation and administration techniques, since an active ingredient with selective action towards non-target species does not currently exist on the market. This document lists practical proposals aimed at reducing the possibility of toxic exposure to anticoagulant rodenticides and mitigate the toxicological risk of human baits and non-target species.

  20. Neutrino physics at the spallation neutron source. Pt. 2

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Lillie, R.A.; Bishop, B.L.; Wilczynski, J.; Zeitnitz, B.

    1981-06-01

    The shielding and detector analysis associated with a contemplated low energy (approx. equal to10 to 50 MeV) neutrino experiment at a spallation neutron source are presented and discussed. This analysis includes neutrino production and interaction rates, time dependence of the neutrino pulse, shielding considerations for neutrons coming directly from the spallation source and those which are scattered from other experimental areas, shielding considerations for galactic sources especially muons and finally detector responses to neutrino and background radiations. In general for a 1 mA (200 ns/pulse, 100 Hz), 1.1 GeV proton beam incident on a lead target surrounded by a moderator system, approximately 8 m of iron are required to reduce the background so that the event rate in the detector systems is approx. [de

  1. Deuterium pass through target

    International Nuclear Information System (INIS)

    Alger, D.L.

    1975-01-01

    A neutron emitting target is described for use in neutron generating apparatus including a deuteron source and an accelerator vacuum chamber. The target consists of a tritium-containing target layer, a deuteron accumulation layer, and a target support containing passages providing communication between the accumulation layer and portions of the surface of the support exposed to the accelerator vacuum chamber. With this arrangement, deuterons passing through the target layer and implanting in and diffusing through the accumulation layer, diffuse into the communicating passages and are returned to the accelerator vacuum chamber. The invention allows the continuous removal of deuterons from the target in conventional water cooled neutron generating apparatus. Preferably, the target is provided with thin barrier layers to prevent undesirable tritium diffusion out of the target layer, as well as deuteron diffusion into the target layer

  2. Pulsed neutron uranium borehole logging with prompt fission neutrons

    International Nuclear Information System (INIS)

    Bivens, H.M.; Smith, G.W.; Jensen, D.H.

    1976-01-01

    The gross count natural gamma log normally used for uranium borehole logging is seriously affected by disequilibrium. Methods for the direct measurement of uranium, such as neutron logging, which are not affected by disequilibrium have been the object of considerable effort in recent years. This paper describes a logging system for uranium which uses a small accelerator to generate pulses of 14 MeV neutrons to detect and assay uranium by the measurement of prompt fission neutrons in the epithermal energy range. After an initial feasibility study, a prototype logging probe was built for field evaluation which began in January 1976. Physical and operational characteristics of the prototype probe, the neutron tube-transformer assembly, and the neutron tube are described. In logging operations, only the epithermal prompt fission neutrons detected between 250 microseconds to 2500 microseconds following the excitation neutron pulse are counted. Comparison of corrected neutron logs with the conventional gross count natural gamma logs and the chemical assays of cores from boreholes are shown. The results obtained with this neutron probe clearly demonstrate its advantages over the gross count natural gamma log, although at this time the accuracy of the neutron log assay is not satisfactory under some conditions. The necessary correction factors for various borehole and formation parameters are being determined and, when applied, should improve the assay accuracy

  3. Photo-neutron cross sections for unstable neutron-rich oxygen isotopes

    International Nuclear Information System (INIS)

    Leistenschneider, A.; Aumann, T.; Boretzky, K.

    2001-05-01

    The dipole response of stable and unstable neutron-rich oxygen nuclei of masses A = 17 to A = 22 has been investigated experimentally utilizing electromagnetic excitation in heavy-ion collisions at beam energies around 600 MeV/nucleon. A kinematically complete measurement of the neutron decay channel in inelastic scattering of the secondary beam projectiles from a Pb target was performed. Differential electromagnetic excitation cross sections dσ/dE were derived up to 30 MeV excitation energy. In contrast to stable nuclei, the deduced dipole strength distribution appears to be strongly fragmented and systematically exhibits a considerable fraction of low-lying strength, exhausting up to 12% of the energy-weighted dipole sum rule at excitation energies below 15 MeV. (orig.)

  4. Target system materials and engineering problems

    International Nuclear Information System (INIS)

    Fischer, W.E.

    1989-01-01

    This paper discusses the common problems of target design. As a model for the discussion, the author considers a spallation source which is fed by a high power proton beam of the order of one megawatt. The materials used for the target station and particularly for the spallation target itself depend on whether the source is built for pulsed, modulated or continuous operation. The difference of materials used is mainly determined by the neutronics considerations. Depending on the choice of materials for the target systems, the characters of material problems met, are of somewhat different nature. It is recognized that for each target version quite specific difficulties have to be overcome. On the other hand, there is a whole set of problems which is common to all target versions. These are: heat load in region of proton beam interactions; thermal stress and cycling; and radiation damage. It is shown that solutions to the whole package of problems up to a beam power of 0 (1MW) have been found. The whole effort concentrates onto the region of the first few centimeters of beam penetration. Two solutions have been proposed: (1) Keep the power of proton beam limited and produce neutrons elsewhere in the target. and (2) Dilute the power by moving mechanically the target and the window. 8 refs., 11 figs

  5. Spallation Neutron Sources For Science And Technology

    International Nuclear Information System (INIS)

    Comsan, M.N.H.

    2011-01-01

    Spallation Neutron Facilities Increasing interest has been noticed in spallation neutron sources (SNS) during the past 20 years. The system includes high current proton accelerator in the GeV region and spallation heavy metal target in the Hg-Bi region. Among high flux currently operating SNSs are: ISIS in UK (1985), SINQ in Switzerland (1996), JSNS in Japan (2008), and SNS in USA (2010). Under construction is the European spallation source (ESS) in Sweden (to be operational in 2020). The intense neutron beams provided by SNSs have the advantage of being of non-reactor origin, are of continuous (SINQ) or pulsed nature. Combined with state-of-the-art neutron instrumentation, they have a diverse potential for both scientific research and diverse applications. Why Neutrons? Neutrons have wavelengths comparable to interatomic spacings (1-5 A) Neutrons have energies comparable to structural and magnetic excitations (1-100 meV) Neutrons are deeply penetrating (bulk samples can be studied) Neutrons are scattered with a strength that varies from element to element (and isotope to isotope) Neutrons have a magnetic moment (study of magnetic materials) Neutrons interact only weakly with matter (theory is easy) Neutron scattering is therefore an ideal probe of magnetic and atomic structures and excitations Neutron Producing Reactions Several nuclear reactions are capable of producing neutrons. However the use of protons minimises the energetic cost of the neutrons produced solid state physics and astrophysics Inelastic neutron scattering

  6. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  7. Report on antimony-beryllium neutron sources examined after 7.45 effective full power years in the Dodewaard BWR

    International Nuclear Information System (INIS)

    Engen, W.R. van; Ainsworth, A.

    1984-01-01

    A source of neutrons is required to check instrumentation in the Dodewaard BWR after each shut-down. The longest shut-down is the annual refuelling shut-down when the reactor is routinely out for several weeks. Thus the isotopic neutron source needs to have a radioactive half-life which is sufficiently longer than several weeks. An appropriate source is antimony-124/ beryllium which has a half-life of 60.9 days. In this source 1.7 MeV gamma rays emitted by antimony-124 bombard the beryllium target material and produce neutrons. A report on the sources falls under the headings: design considerations (active insert; encapsulation (general considerations; chemical considerations; single or double encapsulation; radium-226 emanating source)); source production; post irradiation examination results (visual examination; eddy current tests); conclusions. (U.K.)

  8. MEGAPIE, a 1 MW pilot experiment for a liquid metal spallation target

    International Nuclear Information System (INIS)

    Bauer, G.S.; Salvatores, M.; Heusener, G.

    2001-01-01

    MEGAPIE (Megawatt Pilot Target Experiment) is an initiative launched by Commissariat a l'Energie Atomique, Cadarache (France) and Forschungszentrum Karlsruhe (Germany) in collaboration with Paul Scherrer Institut (Switzerland), to demonstrate, in an international collaboration, the feasibility of a liquid lead bismuth target for spallation facilities at a beam power level of 1 MW. Such a target is under consideration for various concepts of accelerator driven systems (ADS) to be used in transmutation of nuclear waste and other applications world-wide. It also has the potential of increasing significantly the thermal neutron flux available at the spallation neutron source (SINQ) for neutron scattering. SINQ's beam power being close to 1 MW already, this facility offers a unique opportunity to realize such an experiment with a reasonably small number of new ancillary systems. The paper describes the basic features of the experiment and its boundary conditions, the technical concept of the target and underlying research carried out at participating laboratories. (author)

  9. Limitations for qualitative and quantitative neutron activation analysis using reactor neutrons

    International Nuclear Information System (INIS)

    El-Abbady, W.H.; El-Tanahy, Z.H.; El-Hagg, A.A.; Hassan, A.M.

    1999-01-01

    In this work, the most important limitations for qualitative and quantitative analysis using reactor neutrons for activation are reviewed. Each limitation is discussed using different examples of activated samples. Photopeak estimation, nuclear reactions interference and neutron flux measurements are taken into consideration. Solutions for high accuracy evaluation in neutron activation analysis applications are given. (author)

  10. Progress on the IPNS Enriched Uranium Booster Target

    International Nuclear Information System (INIS)

    Knox, A.E.; Carpenter, J.M.; Bailey, J.L.

    1986-09-01

    We describe the Enriched Uranium Booster Target designed for use in Argonne's Intense Pulsed Neutron Source. This report contains a general description of the system, and descriptions of the thermal-hydraulic and loss-of-coolant accident analyses, of the neutronic, criticality and power density calculations, of the assessment of radiation and thermal cycling growth, and of the disk fabrication methods. We also describe the calculations of radionuclide buildup and the related hazards analysis and our calculations of the temperature and stress profiles in the disks, and briefly allude to considerations of security and safeguards

  11. The neutron

    International Nuclear Information System (INIS)

    Kredov, B.M.

    1979-01-01

    The history of the neutron is displayed on the basis of contributions by scientists who produced outstanding results in neutron research (part 1), of summarizing discoveries and theories which led to the discovery of the neutron and the resulting development of nuclear physics (part 2), and of fundamental papers written by Rutherford, Chadwick, Iwanenko, and others (appendix). Of interest to physicists, historians, and students

  12. Neutron techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    The way in which neutrons interact with matter such as slowing-down, diffusion, neutron absorption and moderation are described. The use of neutron techniques in industry, in moisture gages, level and interface measurements, the detection of blockages, boron analysis in ore feedstock and industrial radiography are discussed. (author)

  13. Comparison study on in-core neutron detector for online neutron flux mapping of research and power reactor

    International Nuclear Information System (INIS)

    Zareen Khan Abdul Jalil Khan; Mohd Idris Taib; Izhar Abu Husin; Nurfarhana Ayuni

    2010-01-01

    This paper presents the comparison study on In-Core neutron detector using for online flux mapping of Research and Power reactor. Technical description of in-core neutron also taken into consideration to identify the different characterization of neutron detector and describe on Self Power neutron detector (SPND) for online neutron flux mapping. Able to provide information on the neutron flux distribution and understand how in-core neutron detector are being used in nuclear power plant including to enable to state the principles of neutron detector. (author)

  14. T violating neutron spin rotation asymmetry

    International Nuclear Information System (INIS)

    Masuda, Yasushiro.

    1993-01-01

    A new experiment on T-violation is proposed, where a spin-rotating-neutron transmission through a polarized nuclear target is measuered. The method to control the neutron spin is discussed for the new T-violation experiment. The present method has possibility to provide us more accurate T-violation information than the neutron EDM measurement

  15. Progress of JAERI neutron science project

    International Nuclear Information System (INIS)

    Oyama, Yukio

    1999-01-01

    Neutron Science Project was started at Japan Atomic Energy Research Institute since 1996 for promoting futuristic basic science and nuclear technology utilizing neutrons. For this purpose, research and developments of intense proton accelerator and spallation neutron target were initiated. The present paper describes the current status of such research and developments. (author)

  16. Measured radionuclide production from copper, gold and lead spallation targets

    Energy Technology Data Exchange (ETDEWEB)

    Parish, T.A.; Belian, A.P. [Texas A & M Univ., College Station, TX (United States)

    1995-10-01

    Spallation target materials are chosen so as to produce large numbers of neutrons while at the same time avoiding the creation of long-lived radioactive wastes. While there has been considerable research to determine the number of neutrons produced per incident particle for various target materials, there has been less effort to precisely quantify the types and amounts of radionuclides produced. Accurate knowledge of the radioactive species produced by spallation reactions is important for specifying waste disposal criteria for targets. In order to verify the production rates calculated by LAHET, a study has been conducted using the Texas A&M University (TAMU) Cyclotron to measure radionuclide yields from copper, gold, and lead targets.

  17. Validation of MC models of spallation reactions in thin and thick targets in the GeV range

    International Nuclear Information System (INIS)

    Goldenbaum, F.; Filges, D.; Neef, R.D.; Nuenighoff, K.; Paul, N.; Schaal, H.; Sterzenbach, G.; Tietze, A.; Wohlmuther, M.; Galin, J.; Letourneau, A.; Lott, B.; Peghaire, A.; Pienkowski, L.

    2001-01-01

    In the framework of new projects of intense spallation neutron sources an extensive experimental and theoretical effort is devoted to the precise prediction and optimization of the targets and shielding in terms of reaction cross sections, hadronic interaction lengths and usable neutrons produced in proton induced spallation reactions. Strong constraints on Monte-Carlo high energy transport codes are put by a measurement campaign of the NESSI (neutron scintillator and silicon detector) collaboration. While the predictive power of inter- and intra-nuclear cascade models coupled to evaporation codes and transport systems is excellent as far as neutron production in thick targets is concerned, there are considerable discrepancies not only between experiments and models, but also among the different codes themselves when regarding charged particle production in thin targets. In the current contribution a representative validation will be executed and possible deficiencies within the codes are elaborated. (orig.)

  18. 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)

  19. The Los Alamos Neutron Science Center Spallation Neutron Sources

    International Nuclear Information System (INIS)

    Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

    2017-01-01

    The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources

  20. The Los Alamos Neutron Science Center Spallation Neutron Sources

    Science.gov (United States)

    Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

    The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ∼100 keV. The characteristics of these sources, and

  1. Neutron scattering studies in the actinide region

    International Nuclear Information System (INIS)

    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 14 N, 181 Ta, 232 Th, 238 U and 239 Pu; Prompt fission spectra for 232 Th, 235 U, 238 U and 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

  2. A neutron source for IGISOL-JYFLTRAP: Design and characterisation

    Energy Technology Data Exchange (ETDEWEB)

    Mattera, A.; Pomp, S.; Lantz, M.; Rakopoulos, V.; Solders, A.; Al-Adili, A.; Passoth, E.; Prokofiev, A.V.; Andersson, P.; Hjalmarsson, A. [Uppsala University, BOX 516, Uppsala (Sweden); Bedogni, R.; Esposito, A.; Gentile, A. [INFN-LNF, Frascati (Italy); Bortot, D. [INFN-LNF, Frascati (Italy); Politecnico di Milano, Milano (Italy); Gomez-Ros, J.M. [INFN-LNF, Frascati (Italy); CIEMAT, Madrid (Spain); Introini, M.V.; Pola, A. [Politecnico di Milano, Milano (Italy); Gorelov, D.; Penttilae, H.; Moore, I.D.; Rinta-Antila, S.; Kolhinen, V.S.; Eronen, T. [University of Jyvaeskylae (Finland)

    2017-08-15

    A white neutron source based on the Be(p, nx) reaction for fission studies at the IGISOL-JYFLTRAP facility has been designed and tested. 30MeV protons impinge on a 5mm thick water-cooled beryllium disc. The source was designed to produce at least 10{sup 12} fast neutrons/s on a secondary fission target, in order to reach competitive production rates of fission products far from the valley of stability. The Monte Carlo codes MCNPX and FLUKA were used in the design phase to simulate the neutron energy spectra. Two experiments to characterise the neutron field were performed: the first was carried out at The Svedberg Laboratory in Uppsala (SE), using an Extended-Range Bonner Sphere Spectrometer and a liquid scintillator which used the time-of-flight (TOF) method to determine the energy of the neutrons; the second employed Thin-Film Breakdown Counters for the measurement of the TOF, and activation foils, at the IGISOL facility in Jyvaeskylae (FI). Design considerations and the results of the two characterisation measurements are presented, providing benchmarks for the simulations. (orig.)

  3. Neutron production in spallation reactions of 0.9 and 1.5 GeV protons on a thick lead target. Comparison between experimental data and Monte-Carlo simulations

    International Nuclear Information System (INIS)

    Krasa, A.; Krizek, F.; Wagner, V.; Kugler, A.; Henzl, V.; Henzlova, D.; Majerle, M.; Adam, J.; Caloun, P.; Bradnova, V.; Chultem, D.; Kalinnikov, V.G.; Krivopustov, M.I.; Solnyshkin, A.A.; Stegajlov, V.I.; Tsupko-Sitnikov, V.M.; Tumehndehlgehr, Ts.; Vasil'ev, S.I.

    2005-01-01

    This paper reports on two experiments performed at the Synchrophasotron/Nuclotron accelerator complex at JINR. Relativistic protons with energies 885 MeV and 1.5 GeV hit a massive cylindrical lead target. The spatial and energetic distributions of the neutron field produced by the spallation reactions were measured by the activation of Al, Au, Bi, Co, and Cu foils placed on the surface of the target and close to it. The yields of the radioactive nuclei produced by threshold reactions in these foils were determined by the analyses of their γ spectra. The comparison with Monte-Carlo based simulations was performed both with the LAHET+MCNP code and the MCNPX code

  4. Neutron Production in Spallation Reactions of 0.9 and 1.5 GeV Protons on a Thick Lead Target. Comparison between Experimental Data and Monte-Carlo Simulations

    CERN Document Server

    Krasa, A; Bradnova, V; Caloun, P; Chultem, D; Henzl, V; Henzlová, D; Kalinnikov, V G; Krivopustov, M I; Krízek, F; Kugler, A; Majerle, M; Solnyshkin, A A; Stegailov, V I; Tsoupko-Sitnikov, V M; Tumendelger, T; Vasilev, S I; Wagner, V; Nuclear Physics Institute of Academy of Sciences of Czech Republic, Rez, Czech Republic

    2005-01-01

    This paper reports on two experiments performed at the Synchrophasotron/Nuclotron accelerator complex at JINR. Relativistic protons with energies 885 MeV and 1.5 GeV hit a massive cylindrical lead target. The spatial and energetic distributions of the neutron field produced by the spallation reactions were measured by the activation of Al, Au, Bi, Co, and Cu foils placed on the surface of the target and close to it. The yields of the radioactive nuclei produced by threshold reactions in these foils were determined by the analyses of their $\\gamma$ spectra. The comparison with Monte-Carlo based simulations was performed both with the LAHET+MCNP code and the MCNPX code.

  5. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

    The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)

  6. Nuclear data for neutron therapy: Status and future needs

    International Nuclear Information System (INIS)

    1997-12-01

    This report discusses the status and success of neutron therapy and some of the problems in clinical neutron dosimetry. Existing neutron interaction data, in particular results of kerma factor measurements and data evaluations, are reviewed. Nuclear data relevant for neutron source reactions, collimation, and shielding are also discussed. Finally, physical aspects of the variation of biological effectiveness of neutrons with neutron energy (radiation quality) are set out. Exchange of information between neutron therapy centers is essential, since only clinical experience can determine the optimal absorbed dose, fractionation, target volume, and clinical indications/contra-indications for neutron therapy

  7. Nuclear data for neutron therapy: Status and future needs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    This report discusses the status and success of neutron therapy and some of the problems in clinical neutron dosimetry. Existing neutron interaction data, in particular results of kerma factor measurements and data evaluations, are reviewed. Nuclear data relevant for neutron source reactions, collimation, and shielding are also discussed. Finally, physical aspects of the variation of biological effectiveness of neutrons with neutron energy (radiation quality) are set out. Exchange of information between neutron therapy centers is essential, since only clinical experience can determine the optimal absorbed dose, fractionation, target volume, and clinical indications/contra-indications for neutron therapy. Refs, 44 figs, 19 tabs.

  8. Multidisk neutron velocity selectors

    International Nuclear Information System (INIS)

    Hammouda, B.

    1992-01-01

    Helical multidisk velocity selectors used for neutron scattering applications have been analyzed and tested experimentally. Design and performance considerations are discussed along with simple explanation of the basic concept. A simple progression is used for the inter-disk spacing in the 'Rosta' design. Ray tracing computer investigations are presented in order to assess the 'coverage' (how many absorbing layers are stacked along the path of 'wrong' wavelength neutrons) and the relative number of neutrons absorbed in each disk (and therefore the relative amount of gamma radiation emitted from each disk). We discuss whether a multidisk velocity selector can be operated in the 'reverse' configuration (i.e. the selector is turned by 180 0 around a vertical axis with the rotor spun in the reverse direction). Experimental tests and calibration of a multidisk selector are reported together with evidence that a multidisk selector can be operated in the 'reverse' configuration. (orig.)

  9. 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...

  10. Neutron flux stabilization in the NG-150 neutron generators

    International Nuclear Information System (INIS)

    Kuz'min, L.E.; Makarov, S.A.; Pronman, I.M.

    1986-01-01

    Problem of metal tritium target lifetime increase and neutron flux stabilization in the NG-150 neutron generators is studied. Possibility on neutron flux stabilization using the mass analyzer for low-angle (4 deg and 41 deg) mass separation of a beam in thre components, which fall on a target simultaneously, is confirmed experimentally. Basic generator parameters are: accelerating voltage of 150 kV, total beam current on a target of 1.5 mA, beam current density of 0.3-1.6 mA/cm 2 , beam diameter of 8 mm. The initial neutron flux on the targets of 0.73 mg/cm 2 thick constituted 1.1x10 11 ssup(-1). The neutron flux monitoring was accomplished from recoil proton recording by a plastic scintillator. Flux decrease by more than 5% served as a signel for measuring mass analyzer magnetic field providing beam displacement on a target and restoration of the given flux. The NG-150 generator neutron flux stabilization was attained during 2h

  11. 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.

  12. Neutron cooling and cold-neutron sources (1962)

    International Nuclear Information System (INIS)

    Jacrot, B.

    1962-01-01

    Intense cold-neutron sources are useful in studying solids by the inelastic scattering of neutrons. The paper presents a general survey covering the following aspects: a) theoretical considerations put forward by various authors regarding thermalization processes at very low temperatures; b) the experiments that have been carried out in numerous laboratories with a view to comparing the different moderators that can be used; c) the cold neutron sources that have actually been produced in reactors up to the present time, and the results obtained with them. (author) [fr

  13. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  14. 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...

  15. Neutron spectometers

    International Nuclear Information System (INIS)

    Poortmans, F.

    1977-01-01

    Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

  16. Neutron exposure

    International Nuclear Information System (INIS)

    Prillinger, G.; Konynenburg, R.A. van

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. In chapter 6, LWR-PV neutron transport calculations and dosimetry methods and how they are combined to evaluate the neutron exposure of the steel of pressure vessels are discussed. An effort to correlate neutron exposure parameters with damage is made

  17. Atmospheric neutrons

    International Nuclear Information System (INIS)

    Preszler, A.M.; Moon, S.; White, R.S.

    1976-01-01

    Additional calibrations of the University of California double-scatter neutron and additional analysis corrections lead to the slightly changed neutron fluxes reported here. The theoretical angular distributions of Merker (1975) are in general agreement with our experimental fluxes but do not give the peaks for vertical upward and downward moving neutrons. The theoretical neutron escape current J 2 /sub pi/ (Merker, 1972; Armstrong et al., 1973) is in agreement with the experimental values from 10 to 100 MeV. Our experimental fluxes agree with those of the Kanbach et al. (1974) in the overlap region from 70 to 100 MeV

  18. 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.

  19. Status of ITER neutron diagnostic development

    International Nuclear Information System (INIS)

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

    2005-01-01

    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 well measured 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, 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 neutron flux monitors 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. (author)

  20. Fast neutron therapy in advanced malignant tumour treatment

    International Nuclear Information System (INIS)

    Avinc, A.

    1998-01-01

    In this report the fast neutron therapy applications were examined by thoroughly consideration of the fast neutron sources and the interactions of the fast neutron by the medium. The efficacy of fast neutron radiotherapy with that of patients with locally advanced tumours were compared. Radiological data indicate that fast neutrons could bring benefit in the treatment of some tumour types especially salivary glands, paranasal sinuses, soft tissue sarcomas, prostatic adenocarcinomas, palliative treatment of melanoma and rectum. There is a significant improvement in local/regional control for the neutron group, but no improvement in the survival. The neutron therapy is suggested through which this benefit could be achieved