THE SPALLATION NEUTRON SOURCE PROJECT - PHYSICAL CHALLENGES.

Energy Technology Data Exchange (ETDEWEB)

WEI,J.

2002-06-03

The Spallation Neutron Source (SNS) is designed to reach an average proton beam power of 1.4 MW for pulsed neutron production. This paper summarizes design aspects and physical challenges to the project.

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)

Pulsed spallation Neutron Sources

International Nuclear Information System (INIS)

Carpenter, J.M.

1994-01-01

This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology

Pulsed spallation neutron sources

International Nuclear Information System (INIS)

Carpenter, J.M.

1996-01-01

This paper reviews the early history of pulsed spallation neutron source development ar Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provide a few examples of applications in fundamental condensed matter physics, materials science and technology

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

Neutron PSDs for the next generation of spallation neutron sources

CERN Document Server

Eijk, C W

2002-01-01

A review of R and D for neutron PSDs to be used at anticipated new spallation neutron sources: the Time-of-Flight system facility, European Spallation Source, Spallation Neutron Source and Neutron Arena, is presented. The gas-filled detectors, scintillation detectors and hybrid systems are emphasized.

Testing Procedures and Results of the Prototype Fundamental Power Coupler for the Spallation Neutron Source

International Nuclear Information System (INIS)

M. Stirbet; I.E. Campisi; E.F. Daly; G.K. Davis; M. Drury; P. Kneisel; G. Myneni; T. Powers; W.J. Schneider; K.M. Wilson; Y. Kang; K.A. Cummings; T. Hardek

2001-01-01

High-power RF testing with peak power in excess of 500 kW has been performed on prototype Fundamental Power Couplers (FPC) for the Spallation Neutron Source superconducting (SNS) cavities. The testing followed the development of procedures for cleaning, assembling and preparing the FPC for installation in the test stand. The qualification of the couplers has occurred for the time being only in a limited set of conditions (travelling wave, 20 pps) as the available RF system and control instrumentation are under improvement

Fundamental neutron physics at a 1 MW long pulse spallation neutron source

International Nuclear Information System (INIS)

Greene, G.L.

1995-01-01

Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research

Operational experiences of the spallation neutron source superconducting linac and power ramp-up

International Nuclear Information System (INIS)

Kim, Sang-Ho

2009-01-01

The spallation neutron source (SNS) is a second generation pulsed neutron source and designed to provide a 1-GeV, 1.44-MW proton beam to a mercury target for neutron production. Since the commissioning of the accelerator complex in 2006, the SNS has started its operation for neutron production and beam power ramp-up has been in progress toward the design goal. All subsystems of the SNS were designed and developed for substantial improvements compared to existing accelerators because the design beam power is almost an order of magnitude higher compared to existing neutron facilities and the achievable neutron scattering performance will exceed present sources by more than a factor of 20 to 100. In this paper, the operational experiences with the SNS Superconducting Linac (SCL), Power Ramp-up Plan to reach the design goal and the Power Upgrade Plan (PUP) will be presented including machine, subsystem and beam related issues.

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

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

Materials for spallation neutron sources

International Nuclear Information System (INIS)

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

1996-03-01

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

Introduction to spallation physics and spallation-target design

Energy Technology Data Exchange (ETDEWEB)

Russell, G.J.; Pitcher, E.J.; Daemen, L.L. [Los Alamos National Laboratory, NM (United States)

1995-10-01

When coupled with the spallation process in appropriate target materials, high-power accelerators can be used to produce large numbers of neutrons, thus providing an alternate method to the use of nuclear reactors for this purpose. Spallation offers exciting new possibilities for generating intense neutron fluxes for a variety of applications, including: (a) spallation-neutron sources for materials science research; (b) accelerator-based production of tritium; (c) accelerator-based transmutation of waste; (d) accelerator-based destruction of plutonium; and (e) radioisotope production for medical and energy applications. Target design plays a key role in these applications, with neutron production/leakage being strongly dependent on the incident particle type and energy, and target material and geometry.

Future prospects of imaging at spallation neutron sources

International Nuclear Information System (INIS)

Strobl, M.

2009-01-01

The advent of state-of-the-art spallation neutron sources is a major step forward in efficient neutron production for most neutron scattering techniques. Although they provide lower time-averaged neutron flux than high flux reactor sources, advantage for different instrumental techniques can be derived from the pulsed time structure of the available flux, which can be translated into energy, respectively, wavelength resolution. Conventional neutron imaging on the other hand relies on an intense continuous beam flux and hence falls short in profiting from the new development. Nevertheless, some recently developed novel imaging techniques require and some can benefit from energy resolution. The impact of the emerging spallation sources on different imaging techniques has been investigated, ways to benefit will be identified (where possible) and prospects of future imaging instruments and possible options and layouts at a spallation neutron source will be discussed and outlined.

Pulsed TRIGA reactor as substitute for long pulse spallation neutron source

International Nuclear Information System (INIS)

Whittemore, W.L.

1999-01-01

TRIGA reactor cores have been used to demonstrate various pulsing applications. The TRIGA reactor fuel (U-ZrH x ) is very robust especially in pulsing applications. The features required to produce 50 pulses per second have been successfully demonstrated individually, including pulse tests with small diameter fuel rods. A partially optimized core has been evaluated for pulses at 50 Hz with peak pulsed power up to 100 MW and an average power up to 10 MW. Depending on the design, the full width at half power of the individual pulses can range between 2000 μsec to 3000 μsec. Until recently, the relatively long pulses (2000 μsec to 3000 μsec) from a pulsed thermal reactor or a long pulse spallation source (LPSS) have been considered unsuitable for time-of-flight measurements of neutron scattering. More recently considerable attention has been devoted to evaluating the performance of long pulse (1000 to 4000 μs) spallation sources for the same type of neutron measurements originally performed only with short pulses from spallation sources (SPSS). Adequate information is available to permit meaningful comparisons between CW, SPSS, and LPSS neutron sources. Except where extremely high resolution is required (fraction of a percent), which does require short pulses, it is demonstrated that the LPSS source with a 1000 msec or longer pulse length and a repetition rate of 50 to 60 Hz gives results comparable to those from the 60 MW ILL (CW) source. For many of these applications the shorter pulse is not necessarily a disadvantage, but it is not an advantage over the long pulse system. In one study, the conclusion is that a 5 MW 2000 μsec LPSS source improves the capability for structural biology studies of macromolecules by at least a factor of 5 over that achievable with a high flux reactor. Recent studies have identified the advantages and usefulness of long pulse neutron sources. It is evident that the multiple pulse TRIGA reactor can produce pulses comparable to

Construction and operation of the Spallation Neutron Source: Draft environmental impact statement. Volume 1

International Nuclear Information System (INIS)

1998-12-01

DOE proposes to construct and operate a state-of-the-art, short-pulsed spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation Neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulation ring and a second target. The US needs a high-flux, short-pulsed neutron source to provide the scientific and industrial research communities with a much more intense source of pulsed neutrons for neutron scattering research than is currently available, and to assure the availability of a state-of-the-art facility in the decades ahead. This next-generation neutron source would create new scientific and engineering opportunities. In addition, it would help replace the neutron science capacity that will be lost by the eventual shutdown of existing sources as they reach the end of their useful operating lives in the first half of the next century. This document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this EIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. The No-Action Alternative describes the expected condition of the environment if no action were taken. Four siting alternatives for the Spallation Neutron Source are evaluated: Oak Ridge National Laboratory, Oak Ridge, TN, (preferred alternative); Argonne National Laboratory, Argonne, IL (US); Brookhaven National Laboratory, Upton, NY; and Los Alamos National Laboratory, Los Alamos, NM

A linac for the Spallation Neutron Source

International Nuclear Information System (INIS)

Jason, A.J.

1998-01-01

The Spallation Neutron Source Project (SNS), to be constructed at Oak Ridge National Laboratory, accelerates H - ions to an energy of 1.0 GeV with an average current of 1-mA for injection into an accumulator ring that produces the short intense burst of protons needed for the spallation-neutron source. The linac will be the most intense source of H - ions and as such requires advanced design techniques to meet project technical goals. In particular, low beam loss is stressed for the chopped beam placing strong requirements on the beam dynamics and linac construction. Additionally, the linac is to be upgraded to the 2- and 4-MW beam-power levels with no increase in duty factor. The author gives an overview of the linac design parameters and design choices made

The Spallation Neutron Source accelerator system design

Science.gov (United States)

Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

2014-11-01

The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

Final environmental impact statement, construction and operation of the Spallation Neutron Source Facility. Summary

International Nuclear Information System (INIS)

1999-04-01

DOE proposes to construct and operate a state-of-the-art, short-pulsed, spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation Neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulator ring and a second target. This document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this FEIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. The No-Action Alternative describes the expected condition of the environment if no action were taken. Four siting alternatives for the Spallation Neutron Source are evaluated: Oak Ridge National Laboratory, Oak Ridge, TN, (preferred alternative); Argonne National Laboratory, Argonne, IL; Brookhaven National Laboratory, Upton, NY; and Los Alamos National Laboratory, Los Alamos, NM

Final environmental impact statement, construction and operation of the Spallation Neutron Source. Volume 1

International Nuclear Information System (INIS)

1999-04-01

DOE proposes to construct and operate a state-of-the-art, short-pulsed, spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulator ring and a second target. This document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this FEIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. The No-Action Alternative describes the expected condition of the environment if no action were taken. Four siting alternatives for the Spallation Neutron Source are evaluated: Oak Ridge National Laboratory, Oak Ridge, TN, (preferred alternative); Argonne National Laboratory, Argonne, IL; Brookhaven National Laboratory, Upton, NY; and Los Alamos National Laboratory, Los Alamos, NM

Synchrotron based spallation neutron source concepts

International Nuclear Information System (INIS)

Cho, Y.

1998-01-01

During the past 20 years, rapid-cycling synchrotrons (RCS) have been used very productively to generate short-pulse thermal neutron beams for neutron scattering research by materials science communities in Japan (KENS), the UK (ISIS) and the US (IPNS). The most powerful source in existence, ISIS in the UK, delivers a 160-kW proton beam to a neutron-generating target. Several recently proposed facilities require proton beams in the MW range to produce intense short-pulse neutron beams. In some proposals, a linear accelerator provides the beam power and an accumulator ring compresses the pulse length to the required ∼ 1 micros. In others, RCS technology provides the bulk of the beam power and compresses the pulse length. Some synchrotron-based proposals achieve the desired beam power by combining two or more synchrotrons of the same energy, and others propose a combination of lower and higher energy synchrotrons. This paper presents the rationale for using RCS technology, and a discussion of the advantages and disadvantages of synchrotron-based spallation sources

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)

Irradiation damage of ferritic/martensitic steels: Fusion program data applied to a spallation neutron source

International Nuclear Information System (INIS)

Klueh, R.L.

1997-01-01

Ferritic/martensitic steels were chosen as candidates for future fusion power plants because of their superior swelling resistance and better thermal properties than austenitic stainless steels. For the same reasons, these steels are being considered for the target structure of a spallation neutron source, where the structural materials will experience even more extreme irradiation conditions than expected in a fusion power plant first wall (i.e., high-energy neutrons that produce large amounts of displacement damage and transmutation helium). Extensive studies on the effects of neutron irradiation on the mechanical properties of ferritic/martensitic steels indicate that the major problem involves the effect of irradiation on fracture, as determined by a Charpy impact test. There are indications that helium can affect the impact behavior. Even more helium will be produced in a spallation neutron target material than in the first wall of a fusion power plant, making helium effects a prime concern for both applications. 39 refs., 10 figs

Status of spallation neutron source

Energy Technology Data Exchange (ETDEWEB)

Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

Development of nuclear design criteria for neutron spallation sources

Energy Technology Data Exchange (ETDEWEB)

Sordo, F.; Abanades, A. [E.T.S. Industriales, Madrid Polytechnic University, UPM, J.Gutierrez Abascal, 2 -28006 Madrid (Spain)

2008-07-01

Spallation neutron sources allow obtaining high neutronic flux for many scientific and industrial applications. In recent years, several proposals have been made about its use, notably the European Spallation Source (ESS), the Japanese Spallation Source (JSNS) and the projects of Accelerator-Driven Subcritical reactors (ADS), particularly in the framework of EURATOM programs. Given their interest, it seems necessary to establish adequate design basis for guiding the engineering analysis and construction projects of this kind of installations. In this sense, all works done so far seek to obtain particular solutions to a particular design, but there has not been any general development to set up an engineering methodology in this field. In the integral design of a spallation source, all relevant physical processes that may influence its behaviour must be taken into account. Neutronic aspects (emitted neutrons and their spectrum, generation performance..), thermomechanical (energy deposition, cooling conditions, stress distribution..), radiological (spallation waste activity, activation reactions and residual heat) and material properties alteration due to irradiation (atomic displacements and gas generation) must all be considered. After analysing in a systematic manner the different options available in scientific literature, the main objective of this thesis was established as making a significant contribution to determine the limiting factors of the main aspects of spallation sources, its application range and the criteria for choosing optimal materials. To achieve this goal, a series of general simulations have been completed, covering all the relevant physical processes in the neutronic and thermal-mechanical field. Finally, the obtained criteria have been applied to the particular case of the design of the spallation source of subcritical reactors PDX-ADS and XT-ADS. These two designs, developed under the European R and D Framework Program, represent nowadays

Development of nuclear design criteria for neutron spallation sources

International Nuclear Information System (INIS)

Sordo, F.; Abanades, A.

2008-01-01

Spallation neutron sources allow obtaining high neutronic flux for many scientific and industrial applications. In recent years, several proposals have been made about its use, notably the European Spallation Source (ESS), the Japanese Spallation Source (JSNS) and the projects of Accelerator-Driven Subcritical reactors (ADS), particularly in the framework of EURATOM programs. Given their interest, it seems necessary to establish adequate design basis for guiding the engineering analysis and construction projects of this kind of installations. In this sense, all works done so far seek to obtain particular solutions to a particular design, but there has not been any general development to set up an engineering methodology in this field. In the integral design of a spallation source, all relevant physical processes that may influence its behaviour must be taken into account. Neutronic aspects (emitted neutrons and their spectrum, generation performance..), thermomechanical (energy deposition, cooling conditions, stress distribution..), radiological (spallation waste activity, activation reactions and residual heat) and material properties alteration due to irradiation (atomic displacements and gas generation) must all be considered. After analysing in a systematic manner the different options available in scientific literature, the main objective of this thesis was established as making a significant contribution to determine the limiting factors of the main aspects of spallation sources, its application range and the criteria for choosing optimal materials. To achieve this goal, a series of general simulations have been completed, covering all the relevant physical processes in the neutronic and thermal-mechanical field. Finally, the obtained criteria have been applied to the particular case of the design of the spallation source of subcritical reactors PDX-ADS and XT-ADS. These two designs, developed under the European R and D Framework Program, represent nowadays

Preliminary radiation transport analysis for the proposed National Spallation Neutron Source (NSNS)

International Nuclear Information System (INIS)

Johnson, J.O.; Lillie, R.A.

1997-01-01

The use of neutrons in science and industry has increased continuously during the past 50 years with applications now widely used in physics, chemistry, biology, engineering, and medicine. Within this history, the relative merits of using pulsed accelerator spallation sources versus reactors for neutron sources as the preferred option for the future. To address this future need, the Department of Energy (DOE) has initiated a pre-conceptual design study for the National Spallation Neutron Source (NSNS) and given preliminary approval for the proposed facility to be built at Oak Ridge National Laboratory (ORNL). The DOE directive is to design and build a short pulse spallation source in the 1 MS power range with sufficient design flexibility that it can be upgraded and operated at a significantly higher power at a later stage. The pre-conceptualized design of the NSNS initially consists of an accelerator system capable of delivering a 1 to 2 GeV proton beam with 1 MW of beam power in an approximate 0.5 microsecond pulse at a 60 Hz frequency onto a single target station. The NSNS will be upgraded in stages to a 5 MW facility with two target stations (a high power station operating at 60 Hz and a low power station operating at 10 Hz). Each target station will contain four moderators (combinations of cryogenic and ambient temperature) and 18 beam liens for a total of 36 experiment stations. This paper summarizes the radiation transport analysis strategies for the proposed NSNS facility

Research activities on structure materials of spallation neutron source at SINQ

Energy Technology Data Exchange (ETDEWEB)

Bauer, G.S.; Dai, Y. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-09-01

With the growing interests on powerful spallation neutron sources, especially with liquid metal targets, and accelerator driven energy systems, spallation materials science and technology have been received wide attention. At SINQ, material research activities are focused on: a) liquid metal corrosion; b) radiation damage; and c) interaction of corrosion and radiation damage. (author) 1 fig., refs.

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.)

GEM-based thermal neutron beam monitors for spallation sources

International Nuclear Information System (INIS)

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

2013-01-01

The development of new large area and high flux thermal neutron detectors for future neutron spallation sources, like the European Spallation Source (ESS) is motivated by the problem of 3 He shortage. In the framework of the development of ESS, GEM (Gas Electron Multiplier) is one of the detector technologies that are being explored as thermal neutron sensors. A first prototype of GEM-based thermal neutron beam monitor (bGEM) has been built during 2012. The bGEM is a triple GEM gaseous detector equipped with an aluminum cathode coated by 1μm thick B 4 C layer used to convert thermal neutrons to charged particles through the 10 B(n, 7 Li)α nuclear reaction. This paper describes the results obtained by testing a bGEM detector at the ISIS spallation source on the VESUVIO beamline. Beam profiles (FWHM x =31 mm and FWHM y =36 mm), bGEM thermal neutron counting efficiency (≈1%), detector stability (3.45%) and the time-of-flight spectrum of the beam were successfully measured. This prototype represents the first step towards the development of thermal neutrons detectors with efficiency larger than 50% as alternatives to 3 He-based gaseous detectors

Neutron scattering instruments for the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Crawford, R.K.; Fornek, T.; Herwig, K.W.

1998-01-01

The Spallation Neutron Source (SNS) is a 1 MW pulsed spallation source for neutron scattering planned for construction at Oak Ridge National Laboratory. This facility is being designed as a 5-laboratory collaboration project. This paper addresses the proposed facility layout, the process for selection and construction of neutron scattering instruments at the SNS, the initial planning done on the basis of a reference set of ten instruments, and the plans for research and development (R and D) to support construction of the first ten instruments and to establish the infrastructure to support later development and construction of additional instruments

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)

New scientific horizons with pulsed spallation neutron sources

International Nuclear Information System (INIS)

Carlile, C.J.; Finney, J.L.

1991-01-01

Pulsed spallation sources are not just another way of producing neutrons: the time structure of the neutron pulse has consequences which allow new scientific areas to be investigated and traditional areas to be explored afresh. In addition to the high epithermal neutron component traditionally associated with pulsed sources the recent development of cold neutron techniques at ISIS illustrates that very high energy and momentum resolutions can be achieved on pulsed sources over a surprisingly wide range. (orig.)

Materials performance experience at spallation neutron sources

Energy Technology Data Exchange (ETDEWEB)

Sommer, W.F. [Los Alamos National Laboratory, NM (United States)

1995-10-01

There is a growing, but not yet substantial, data base for materials performance at spallation neutron sources. Specially designed experiments using medium energy protons (650 MeV) have been conducted at the Proton Irradiation Experiment (PIREX) facility at the Swiss Nuclear Institute accelerator (SIN). Specially designed experiments using 760-800 MeV copper target have been completed at the Los Alamos Spallation Radiation Effects Facility (LASREF) at Los Alamos Meson Physics Facility (LAMPF). An extensive material testing program was initiated at LASREF in support of the German spallation neutron source (SNQ) project, before it terminated in 1985.

Neutronic performance issues for the Spallation Neutron Source moderators

International Nuclear Information System (INIS)

Iverson, E.B.; Murphy, B.D.

2001-01-01

We continue to develop the neutronic models of the Spallation Neutron Source target station and moderators in order to better predict the neutronic performance of the system as a whole and in order to better optimize that performance. While we are not able to say that every model change leads to more intense neutron beams being predicted, we do feel that such changes are advantageous in either performance or in the accuracy of the prediction of performance. We have computationally and experimentally studied the neutronics of hydrogen-water composite moderators such as are proposed for the SNS Project. In performing these studies, we find that the composite moderator, at least in the configuration we have examined, does not provide performance characteristics desirable for the instruments proposed and being designed for this neutron scattering facility. The pulse width as a function of energy is significantly broader than for other moderators, limiting attainable resolution-bandwidth combinations. Furthermore, there is reason to expect that higher-energy (0.1-1 eV) applications will be significantly impacted by bimodal pulse shapes requiring enormous effort to parameterize. As a result of these studies, we have changed the SNS design, and will not use a composite moderator at this time. We have analyzed the depletion of a gadolinium poison plate in a hydrogen moderator at the Spallation Neutron Source, and found that conventional poison thicknesses will be completely unable to last the desired component lifetime of three operational years. A poison plate 300-600 μm thick will survive for the required length of time, but will somewhat degrade the intensity (by as much as 15% depending on neutron energy) and the consistency of the neutron source performance. Our results should scale fairly easily to other moderators on this or any other spallation source. While depletion will be important for all highly-absorbing materials in high-flux regions, we feel it likely that

Neutron moderators for the European Spallation Source

DEFF Research Database (Denmark)

Klinkby, Esben Bryndt; Zanini, L.; Batkov, K.

The design of the neutron moderators for the European Spallation Source, intended to be installed at the start of operations of the facility in 2019 has now been finalized and the moderators are being fabricated. Among the driving principles in the design have been flexibility for instruments...... to have access to cold and thermal neutrons with highest possible source brightness. Different design and configuration options were evaluated. The final configuration accepted for construction foresees two moderators with identical para-hydrogen (so-called "butterfly") shape, but different heights......, placed above and below the spallation target. Both moderators are able to serve the full 2 x 120° beam extraction sectors of instrument suite. The top, 3-cm tall moderator, has both high thermal and high cold brightness, more than by a factor of 2.5 compared to the previous design of the Technical Design...

Advanced spallation neutron sources for condensed matter research

International Nuclear Information System (INIS)

Lovesey, S.W.; Stirling, G.C.

1984-03-01

Advanced spallation neutron sources afford significant advantages over existing high flux reactors. The effective flux is much greater than that currently available with reactor sources. A ten-fold increase in neutron flux will be a major benefit to a wide range of condensed matter studies, and it will realise important experiments that are marginal at reactor sources. Moreover, the high intensity of epithermal neutrons open new vistas in studies of electronic states and molecular vibrations. (author)

Beam Instrumentation for the Spallation Neutron Source Ring

International Nuclear Information System (INIS)

Witkover, R. L.; Cameron, P. R.; Shea, T. J.; Connolly, R. C.; Kesselman, M.

1999-01-01

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

Radiation physics of high power spallation targets. State of the art simulation methods and experiments, the 'European Spallation Source' (ESS)

International Nuclear Information System (INIS)

Filges, D.; Cloth, P.; Neef, R.D.; Schaal, H.

1998-01-01

Particle transport and nuclear interactions of planned high power spallation targets with GeV proton beams can be simulated using widely developed Monte Carlo transport methods. This includes available high energy radiation transport codes and systems for low energy, earlier developed for reactor physics and fusion technology. Monte Carlo simulation codes and applied methods are discussed. The capabilities of the world-wide existing state-of-the-art computer code systems are demonstrated. Results of computational studies for the 'European Spallation Source' (ESS) mercury high power target station are given. The needs for spallation related data and planned experiments are shown. (author)

EXPERIMENTAL ANALYSES OF SPALLATION NEUTRONS GENERATED BY 100 MEV PROTONS AT THE KYOTO UNIVERSITY CRITICAL ASSEMBLY

Directory of Open Access Journals (Sweden)

CHEOL HO PYEON

2013-02-01

Full Text Available Neutron spectrum analyses of spallation neutrons are conducted in the accelerator-driven system (ADS facility at the Kyoto University Critical Assembly (KUCA. High-energy protons (100 MeV obtained from the fixed field alternating gradient accelerator are injected onto a tungsten target, whereby the spallation neutrons are generated. For neutronic characteristics of spallation neutrons, the reaction rates and the continuous energy distribution of spallation neutrons are measured by the foil activation method and by an organic liquid scintillator, respectively. Numerical calculations are executed by MCNPX with JENDL/HE-2007 and ENDF/B-VI libraries to evaluate the reaction rates of activation foils (bismuth and indium set at the target and the continuous energy distribution of spallation neutrons set in front of the target. For the reaction rates by the foil activation method, the C/E values between the experiments and the calculations are found around a relative difference of 10%, except for some reactions. For continuous energy distribution by the organic liquid scintillator, the spallation neutrons are observed up to 45 MeV. From these results, the neutron spectrum information on the spallation neutrons generated at the target are attained successfully in injecting 100 MeV protons onto the tungsten target.

Spallation neutrons pulsed sources

International Nuclear Information System (INIS)

Carpenter, J.

1996-01-01

This article describes the range of scientific applications which can use these pulsed neutrons sources: Studies on super fluids, measures to verify the crawling model for the polymers diffusion; these sources are also useful to study the neutron disintegration, the ultra cold neutrons. In certain applications which were not accessible by neutrons diffusion, for example, radiations damages, radionuclides production and activation analysis, the spallation sources find their use and their improvement will bring new possibilities. Among others contributions, one must notice the place at disposal of pulsed muons sources and neutrinos sources. (N.C.). 3 figs

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

Radiation problems expected for the German spallation neutron source

International Nuclear Information System (INIS)

Goebel, K.

1981-01-01

The German project for the construction of a Spallation Neutron Source with high proton beam power (5.5 MW) will have to cope with a number of radiation problems. The present report describes these problems and proposes solutions for keeping exposures for the staff and release of activity and radiation into the environment as low as reasonably achievable. It is shown that the strict requirements of the German radiation protection regulations can be met. The main problem will be the exposure of maintenance personnel to remanent gamma radiation, as is the case at existing proton accelerators. Closed ventilation and cooling systems will reduce the release of (mainly short-lived) activity to acceptable levels. Shielding requirements for different sections are discussed, and it is demonstrated by calculations and extrapolations from experiments that fence-post doses well below 150 mrem/y can be obtained at distances of the order of 100 metres from the principal source points. The radiation protection system proposed for the Spallation Neutron Source is discussed, in particular the needs for monitor systems and a central radiation protection data base and alarm system. (orig.)

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

New neutron physics using spallation sources

International Nuclear Information System (INIS)

Bowman, C.D.

1988-01-01

The extraordinary neutron intensities available from the new spallation pulsed neutron sources open up exciting opportunities for basic and applied research in neutron nuclear physics. The energy range of neutron research which is being explored with these sources extends from thermal energies to almost 800 MeV. The emphasis here is on prospective experiments below 100 keV neutron energy using the intense neutron bursts produced by the Proton Storage Ring (PSR) at Los Alamos. 30 refs., 10 figs

Characterization of the radiation background at the Spallation Neutron Source

International Nuclear Information System (INIS)

DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Hall-Wilton, Richard J.; Bentley, Phillip M.; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.

2016-01-01

We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4 He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden. (paper)

Safety techniques in the change of nuclear systems. Radiation protection at spallation neutron sources and transmutation facilities

International Nuclear Information System (INIS)

Nuenighoff, Kay

2009-01-01

To push the boundary towards higher neutron fluxes concepts based on spallation reactions have been discussed. Here neutrons are produced by bombarding a heavy metal target (e.g. mercury, tungsten, or tantalum) with high energetic protons. Up to now such facilities could not be realised because of the high power particle accelerators needed. Recent developments of the accelerator technology open the possibility of construction and operating proton accelerators in the MW region. This is demonstrated by construction and commissioning of two MW spallation neutron sources, namely SNS (Oak Ridge, Tennessee, USA) with a power of 1.4 MW and J-PARC (Japan) with 1 MW. The realisation of proton accelerators at this power level will open the way towards energy amplifiers, as proposed e.g. by Carlo Rubbia. Such a facility will not only produce electric power. Furthermore longliving radionuclides can be transmutated into shortlived or even stable nuclides by neutron induced nuclear reactions. A mitigation of the problem of nuclear waste disposal. The above discussed developments prove that accelerators are not only constructed for research, moreover application of these technology became state of the art. With the emergence of particle accelerators in the MW region, radiation protection is confronted with new kind of problems to be solved. Especially the higher kinetic energies of the primary beam particles requires modification and expansion of computer programs well known in nuclear engineering. In contrast to nuclear reactors with kinetic energies up to 2-3 MeV, in spallation reaction secondary particles up to the incident energy in the GeV region will be produced. Problems related to radiation protection have to be considered in an energy range three orders of magnitude higher than known from nuclear reactors. In this thesis existing computer codes are compared and validated with data from selected experiments. Questions concerning radiation protection covers a broad range

Spallation neutron source moderator design

International Nuclear Information System (INIS)

Charlton, L.A.; Barnes, J.M.; Gabriel, T.A.; Johnson, J.O.

1998-01-01

This paper describes various aspects of the spallation neutron source (SNS) moderator design. Included are the effects of varying the moderator location, interaction effects between moderators, and the impact on neutron output when various reflector materials are used. Also included is a study of the neutron output from composite moderators, where it is found that a combination of liquid H 2 O and liquid H 2 can produce a spectrum very similar to liquid methane (L-CH 4 ). (orig.)

The US spallation neutron source (SNS) project

International Nuclear Information System (INIS)

Alonso, J.R.

1999-01-01

The SNS is a 1 MW pulsed spallation neutron source that will be sited at Oak Ridge. It will consist of a high-current, normal-conducting linac accelerating an H - beam to 1 GeV, an accumulator ring which compresses each 1 ms linac pulse into a 600 ns bunch which is then extracted in a single turn onto a liquid mercury target. Neutron pulses emerge at a 60 Hz rate from the two ambient, and two cryogenic moderators. Eighteen beam ports surrounding the target station are available for neutron-scattering instrumentation. Funds for ten instruments are included in the construction project; these instruments will provide basic measurement capability for the many and varied research activities at the SNS facility. The new spallation source is being built by a consortium of laboratories; the partners are LBNL, LANL, BNL, ANL and ORNL. The breadth and depth of experience and resources brought by such a wide-spread team offers very significant advantages. Construction will start in October of 1998, operation will begin in October, 2005. (J.P.N.)

Triple ion-beam studies of radiation damage effects in a 316LN austenitic alloy for a high power spallation neutron source

International Nuclear Information System (INIS)

Lee, E.H.; Rao, G.R.; Hunn, J.D.; Rice, P.M.; Lewis, M.B.; Cook, S.W.; Farrell, K.; Mansur, L.K.

1997-09-01

Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe ++ , 360 keV He + , and 180 keV H + to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of ∼ 1 microm. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron microscopy (TEM) and a nanoindentation technique, respectively. TEM investigation yielded varying damage defect microstructures, comprising black dots, faulted and unfaulted loops, and a high number density of fine bubbles (typically less than 1 nm in diameter). With increasing temperature, faulted loops had a tendency to unfault, and bubble microstructure changed from a bimodal size distribution to a unimodal distribution. Triple ion irradiations at the three temperatures resulted in similar increases in hardness of approximately a factor of two. Individually, Fe and He ions resulted in a similar magnitude of hardness increase, whereas H ions showed only a very small effect. The present study has yielded microstructural information relevant to spallation neutron source conditions and indicates that the most important concern may be radiation induced hardening and associated ductility loss

Triple Ion-Beam Studies of Radiation Damage Effects in a 316LN Austenitic Alloy for a High Power Spallation Neutron Source

International Nuclear Information System (INIS)

Lee, E.H.

2001-01-01

Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe 2 , 360 keV He + , and 180 keV H + to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of ∼ 1 microm. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron microscopy (TEM) and a nanoindentation technique, respectively. TEM investigation yielded varying damage defect microstructures, comprising black dots, faulted and unfaulted loops, and a high number density of fine bubbles (typically less than 1 nm in diameter). With increasing temperature, faulted loops had a tendency to unfault, and bubble microstructure changed from a bimodal size distribution to a unimodal distribution. Triple ion irradiations at the three temperatures resulted in similar increases in hardness of approximately a factor of two. Individually, Fe and He ions resulted in a similar magnitude of hardness increase, whereas H ions showed only a very small effect. The present study has yielded microstructural information relevant to spallation neutron source conditions and indicates that the most important concern may be radiation induced hardening and associated ductility loss

Construction and operation of the Spallation Neutron Source: Draft environmental impact statement. Volume 2

International Nuclear Information System (INIS)

1998-12-01

DOE proposes to construct and operate a state-of-the-art, short-pulsed spallation neutron source comprised of an ion source, a linear accelerator, a proton accumulator ring, and an experiment building containing a liquid mercury target and a suite of neutron scattering instrumentation. The proposed Spallation Neutron Source would be designed to operate at a proton beam power of 1 megawatt. The design would accommodate future upgrades to a peak operating power of 4 megawatts. These upgrades may include construction of a second proton accumulation ring and a second target. Volume 1 of this document analyzes the potential environmental impacts from the proposed action and the alternatives. The analysis assumes a facility operating at a power of 1 MW and 4 MW over the life of the facility. The two primary alternatives analyzed in this EIS are: the proposed action (to proceed with building the Spallation Neutron Source) and the No-Action Alternative. This volume contains the following appendices: (A) SNS accident source terms for EIS input; (B) Reports on the selection of alternative sites for the SNS; (C) Letters of consultation on protected species and cultural resources; (D) Ecological resource survey reports and summaries; (E) Descriptions of ORNL research projects in the Walker Branch Watershed; (F) Atmospheric dispersion and dose calculations for normal and accident conditions; (G) Projected air quality modeling effects at NOAA's Walker Branch Monitoring Tower

Spallator - accelerator breeder

International Nuclear Information System (INIS)

Steinberg, M.

1985-01-01

The concept involves the use of spallation neutrons produced by interaction of a high energy proton (1 to 2 GeV) from a linear accelerator (LINAC) with a heavy metal target (uranium). The principal spallator concept is based on generating fissile fuel for use in LWR nuclear power plants. The spallator functions in conjunction with a reprocessing plant to regenerate and produce the Pu-239 or U-233 for fabrication into fresh LWR reactor fuel elements. Advances in proton accelerator technology has provided a solid base for predicting performance and optimizing the design of a reliable, continuous wave, high-current LINAC required by a fissile fuel production machine

The Spallation Neutron Source Beam Commissioning and Initial Operations

Energy Technology Data Exchange (ETDEWEB)

Henderson, Stuart [Argonne National Lab. (ANL), Argonne, IL (United States); Aleksandrov, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Assadi, Saeed [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bartoski, Dirk [University of Texas, Houston, TX (United States). Anderson Cancer Center; Blokland, Willem [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Casagrande, F. [Michigan State Univ., East Lansing, MI (United States); Campisi, I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chu, C. [Michigan State Univ., East Lansing, MI (United States); Cousineau, Sarah M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Crofford, Mark T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Danilov, Viatcheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deibele, Craig E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dodson, George W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feshenko, A. [Inst. for Nuclear Research (INR), Moscow (Russian Federation); Galambos, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Han, Baoxi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hardek, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Howell, Matthew P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jeon, D. [Inst. for Basic Science, Daejeon (Korea); Kang, Yoon W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kasemir, Kay [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kravchuk, L. [Institute for Nuclear Research (INR), Moscow (Russian Federation); Long, Cary D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McManamy, T. [McManamy Consulting, Inc., Middlesex, MA (United States); Pelaia, II, Tom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Piller, Chip [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Plum, Michael A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pogge, James R. [Tennessee Technological Univ., Cookeville, TN (United States); Purcell, John David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shea, T. [European Spallation Source, Lund (Sweden); Shishlo, Andrei P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sibley, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stockli, Martin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stout, D. [Michigan State Univ., East Lansing, MI (United States); Tanke, E. [European Spallation Source, Lund (Sweden); Welton, Robert F [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Y. [Michigan State Univ., East Lansing, MI (United States); Zhukov, Alexander P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-09-01

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

New spallation neutron sources, their performance and applications

International Nuclear Information System (INIS)

1985-01-01

Pulsed spallation sources now operating in the world are at the KEK Laboratory in Japan (the KENS source), at Los Alamos National Laboratory (WNR) and at Argonne National Laboratory (IPNS), both the latter being in the US. The Intense Pulsed Neutron Source (IPNS) is currently the world's most intense source with a peak neutron flux of 4 x 10 14 n cm -2 s -1 at a repetition rate of 30 Hz, and globally producing approx. 1.5 x 10 15 n/sec. Present pulsed sources are still relatively weak compared to their potential. In 1985 the Rutherford Spallation Neutron Source will come on line, and eventually be approx. 30 more intense than the present IPNS. Later, in 1986 the WNR/PSR option at Los Alamos will make that facility of comparable intensity, while a subcritical fission booster at IPNS will keep IPNS competitive. These new sources will expand the applications of pulsed neutrons but are still based on accelerators built for other scientific purposes, usually nuclear or high-energy physics. Accelerator physicists are now designing machines expressly for spallation neutron research, and the proton currents attainable appear in the milliamps. (IPNS now runs at 0.5 GeV and 14 μA). Such design teams are at the KFA Laboratory Julich, Argonne National Laboratory and KEK. Characteristics, particularly the different time structure of the pulses, of these new sources will be discussed. Such machines will be expensive and require national, if not international, collaboration across a wide spectrum of scientific disciplines. The new opportunities for neutron research will, of course, be dramatic with these new sources

CHINA SPALLATION NEUTRON SOURCE PROJECT: DESIGN ITERATIONS AND R AND D STATUS

International Nuclear Information System (INIS)

WEI, J.

2006-01-01

The China Spallation Neutron Source (CSNS) is an accelerator based high power project currently under preparation in China. The accelerator complex is based on an H - linear accelerator and a rapid cycling proton synchrotron. During the past year, the design of most accelerator systems went through major iterations, and initial research and developments were started on the prototyping of several key components. This paper summarizes major activities of the past year

High energy neutron radiography

International Nuclear Information System (INIS)

Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

1996-01-01

High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

Studies Performed in Preparation for the Spallation Neutron Source Accumulator Ring Commissioning

CERN Document Server

Cousineau, Sarah M; Henderson, Stuart; Holmes, Jeffrey Alan; Plum, Michael

2005-01-01

The Spallation Neutron Source accumulator ring will compress 1.5?1014, 1 GeV protons from a 1 ms bunch train to a single 695 ns proton bunch for use in neutron spallation. Due to the high beam power, unprecedented control of beam loss will be required in order to control radiation and allow for hands-on maintenance in most areas of the ring. A number of detailed investigations have been performed to understand the primary sources of beam loss and to predict and mitigate problems associated with radiation hot spots in the ring. The ORBIT particle tracking code is used to perform realistic simulations of the beam accumulation in the ring, including detailed modeling of the injection system, transport through the measured magnet fields including higher order multipoles, and beam loss and collimation. In this paper we present the results of a number of studies performed in preparation for the 2006 commissioning of the accumulator ring.

Accelerator driven reactors, - the significance of the energy distribution of spallation neutrons on the neutron statistics

Energy Technology Data Exchange (ETDEWEB)

Fhager, V

2000-01-01

In order to make correct predictions of the second moment of statistical nuclear variables, such as the number of fissions and the number of thermalized neutrons, the dependence of the energy distribution of the source particles on their number should be considered. It has been pointed out recently that neglecting this number dependence in accelerator driven systems might result in bad estimates of the second moment, and this paper contains qualitative and quantitative estimates of the size of these efforts. We walk towards the requested results in two steps. First, models of the number dependent energy distributions of the neutrons that are ejected in the spallation reactions are constructed, both by simple assumptions and by extracting energy distributions of spallation neutrons from a high-energy particle transport code. Then, the second moment of nuclear variables in a sub-critical reactor, into which spallation neutrons are injected, is calculated. The results from second moment calculations using number dependent energy distributions for the source neutrons are compared to those where only the average energy distribution is used. Two physical models are employed to simulate the neutron transport in the reactor. One is analytical, treating only slowing down of neutrons by elastic scattering in the core material. For this model, equations are written down and solved for the second moment of thermalized neutrons that include the distribution of energy of the spallation neutrons. The other model utilizes Monte Carlo methods for tracking the source neutrons as they travel inside the reactor material. Fast and thermal fission reactions are considered, as well as neutron capture and elastic scattering, and the second moment of the number of fissions, the number of neutrons that leaked out of the system, etc. are calculated. Both models use a cylindrical core with a homogenous mixture of core material. Our results indicate that the number dependence of the energy

Accelerator driven reactors, - the significance of the energy distribution of spallation neutrons on the neutron statistics

International Nuclear Information System (INIS)

Fhager, V.

2000-01-01

In order to make correct predictions of the second moment of statistical nuclear variables, such as the number of fissions and the number of thermalized neutrons, the dependence of the energy distribution of the source particles on their number should be considered. It has been pointed out recently that neglecting this number dependence in accelerator driven systems might result in bad estimates of the second moment, and this paper contains qualitative and quantitative estimates of the size of these efforts. We walk towards the requested results in two steps. First, models of the number dependent energy distributions of the neutrons that are ejected in the spallation reactions are constructed, both by simple assumptions and by extracting energy distributions of spallation neutrons from a high-energy particle transport code. Then, the second moment of nuclear variables in a sub-critical reactor, into which spallation neutrons are injected, is calculated. The results from second moment calculations using number dependent energy distributions for the source neutrons are compared to those where only the average energy distribution is used. Two physical models are employed to simulate the neutron transport in the reactor. One is analytical, treating only slowing down of neutrons by elastic scattering in the core material. For this model, equations are written down and solved for the second moment of thermalized neutrons that include the distribution of energy of the spallation neutrons. The other model utilizes Monte Carlo methods for tracking the source neutrons as they travel inside the reactor material. Fast and thermal fission reactions are considered, as well as neutron capture and elastic scattering, and the second moment of the number of fissions, the number of neutrons that leaked out of the system, etc. are calculated. Both models use a cylindrical core with a homogenous mixture of core material. Our results indicate that the number dependence of the energy

The spallation neutron source: New opportunities

Indian Academy of Sciences (India)

The spallation neutron source (SNS) facility became operational in the spring of ... the opportunity to develop science and instrumentation programs which take ... in telecommunications, manufacturing, transportation, information technology, ...

PROCEEDINGS ON SYNCHROTRON RADIATION: China Spallation Neutron Source - an overview of application prospects

Science.gov (United States)

Wei, Jie; Fu, Shi-Nian; Tang, Jing-Yu; Tao, Ju-Zhou; Wang, Ding-Sheng; Wang, Fang-Wei; Wang, Sheng

2009-11-01

The China Spallation Neutron Source (CSNS) is an accelerator-based multidisciplinary user facility to be constructed in Dongguan, Guangdong, China. The CSNS complex consists of an H- linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a solid-tungsten target station, and instruments for spallation neutron applications. The facility operates at 25 Hz repetition rate with an initial design beam power of 120 kW and is upgradeable to 500 kW. Construction of the CSNS project will lay the foundation of a leading national research center based on advanced proton-accelerator technology, pulsed neutron-scattering technology, and related programs including muon, fast neutron, and proton applications as well as medical therapy and accelerator-driven subcritical reactor (ADS) applications to serve China's strategic needs in scientific research and technological innovation for the next 30 plus years.

High power operation of the polyphase resonant converter modulator system for the spallation neutron source linear accelerator

CERN Document Server

Reass, W A; Baca, D M; Doss, J D; Gonzáles, J M; Gribble, R F; Trujillo, P G

2003-01-01

The spallation neutron source (SNS) is a new 1.4 MW average power beam, 1 GeV accelerator being built at Oak Ridge national laboratory. The accelerator requires 15 "long-pulse" converter-modulator stations each providing a maximum of 11 MW pulses with a 1.1 MW average power. Two variants of the converter-modulator are utilized, an 80 kV and a 140 kV design, the voltage dependant on the type of klystron load. The converter-modulator can be described as a resonant zero-voltage- switching polyphase boost inverter. As noted in Figure 1, each converter modulator derives its buss voltage from a standard 13.8 kV to 2100 Y (1.5 MVA) substation cast-core transformer. The substation also contains harmonic traps and filters to accommodate IEEE 519 and 141 regulations. Each substation is followed by an SCR preregulator to accommodate system voltage changes from no load to full load, in addition to providing a soft-start function. Energy storage and filtering is provided by special low inductance self-clearing metallized ...

Mitigation technologies for damage induced by pressure waves in high-power mercury spallation neutron sources (1). Material surface improvement

International Nuclear Information System (INIS)

Naoe, Takashi; Futakawa, Masatoshi; Wakui, Takashi; Kogawa, Hiroyuki; Shoubu, Takahisa; Takeuchi, Hirotsugu; Kawai, Masayoshi

2008-01-01

Liquid-mercury target systems for MW-class spallation neutron sources are being developed in the world. Proton beams will be used to induce the spallation reaction. At the moment the proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. Localized impacts by microjets and/or shock waves that are caused by cavitation bubble collapse impose pitting damage on the vessel wall. Bubble collapse behavior was observed by using a high-speed video camera, as well as simulated numerically. Localized impact due to cavitation bubble collapse was quantitatively estimated through comparison between numerical simulation and experiment. A novel surface treatment technique that consists of carburizing and nitriding processes was developed and the treatment condition was optimized to mitigate the pitting damage due to localized impacts. (author)

Science opportunities at high power accelerators like APT

International Nuclear Information System (INIS)

Browne, J.C.

1996-01-01

This paper presents applications of high power RF proton linear accelerators to several fields. Radioisotope production is an area in which linacs have already provided new isotopes for use in medical and industrial applications. A new type of spallation neutron source, called a long-pulse spallation source (LPSS), is discussed for application to neutron scattering and to the production and use of ultra-cold neutrons (UCN). The concept of an accelerator-driven, transmutation of nuclear waste system, based on high power RF linac technology, is presented along with its impact on spent nuclear fuels

Technology and science at a high-power spallation source: Proceedings

Energy Technology Data Exchange (ETDEWEB)

1994-01-01

These proceedings cover many aspects of the usefulness of spallation neutrons. Nine different areas are considered: surfaces and interfaces, engineering, materials science, polymers and complex fluids, chemistry, structural biology, nuclear engineering and radiation effects, condensed matter physics and fundamental physics.

Technology and science at a high-power spallation source: Proceedings

International Nuclear Information System (INIS)

1994-01-01

These proceedings cover many aspects of the usefulness of spallation neutrons. Nine different areas are considered: surfaces and interfaces, engineering, materials science, polymers and complex fluids, chemistry, structural biology, nuclear engineering and radiation effects, condensed matter physics and fundamental physics

Overview of Neutron Science Project

Energy Technology Data Exchange (ETDEWEB)

Mukaiyama, Takehiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-11-01

JAERI has launched the Neutron Science Project which aims at bringing scientific and technological innovation for the 21st century in the fields of basic science and nuclear technology using a high power spallation neutron source. The Project is preparing the design for a high intensity pulsed and cw spallation neutron sources for such basic science as neutron structural biology, material science, and for accelerator-driven transmutation of long-lived radio-nuclides which are associated with nuclear power generation. The major facilities to be constructed under the Project are, (1) a super-conducting proton linac with the proton energy of 1.5 GeV and the maximum beam power of 8 MW, (2) a spallation target station with input beam power of 5 MW allowing high intensity pulsed neutron beams for neutron scattering, and (3) research facility complex for accelerator-driven transmutation experiments, neutron physics, material irradiation, isotopes production, spallation produced RI beam experiments for exotic nuclei investigation. (author)

Overview of Neutron Science Project

International Nuclear Information System (INIS)

Mukaiyama, Takehiko

1997-01-01

JAERI has launched the Neutron Science Project which aims at bringing scientific and technological innovation for the 21st century in the fields of basic science and nuclear technology using a high power spallation neutron source. The Project is preparing the design for a high intensity pulsed and cw spallation neutron sources for such basic science as neutron structural biology, material science, and for accelerator-driven transmutation of long-lived radio-nuclides which are associated with nuclear power generation. The major facilities to be constructed under the Project are, 1) a super-conducting proton linac with the proton energy of 1.5 GeV and the maximum beam power of 8 MW, 2) a spallation target station with input beam power of 5 MW allowing high intensity pulsed neutron beams for neutron scattering, and 3) research facility complex for accelerator-driven transmutation experiments, neutron physics, material irradiation, isotopes production, spallation produced RI beam experiments for exotic nuclei investigation. (author)

Neutronic moderator design for the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Charlton, L.A.; Barnes, J.M.; Johnson, J.O.; Gabriel, T.A.

1998-01-01

Neutronics analyses are now in progress to support the initial selection of moderator design parameters for the Spallation Neutron Source (SNS). The results of the initial optimization studies involving moderator poison plate location, moderator position, and premoderator performance for the target system are presented in this paper. Also presented is an initial study of the use of a composite moderator to produce a liquid methane like spectrum

Experimental and Theoretical Investigations to Improve the Predictive Power of Nuclear Reaction Models in Spallation Neutron Production

International Nuclear Information System (INIS)

Nuenighoff, K.; Filges, D.; Goldenbaum, F.; Neef, R.D.; Nuenighoff, K.; Paul, N.; Schaal, H.; Sterzenbach, G.; Wohlmuther, M.; Enke, M.; Herbach, C.M.; Hilscher, D.; Jahnke, U.; Tishchenko, V.; Galin, J.; Letourneau, A.; Lott, B.; Peghaire, A.; Pienkowski, L.; Schroeder, U.; Toke, J.; Tietze, A.

2002-01-01

In order to design the target station of the European Spallation Source ESS measurements of the neutron production in possible target materials like Pb, Hg and W were performed. The aim of these measurements was to validate the simulation codes and to proof their predictive power. The NESSI experiment allows for the comparison of neutron multiplicity distributions between experiment and simulation, which is a much more sensitive method than only comparing the mean neutron multiplicities. An agreement of better than 10 % was achieved. Various target geometries with diameters up to 15 cm and lengths up to 35 cm over a range from 0.4 till 2.5 GeV incident proton energy were studied. The Monte-Carlo Simulations were performed with the HERMES, LCS, and MCNPX code system. (authors)

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

Spallator and APEX nuclear fuel cycle: a new option for nuclear power

International Nuclear Information System (INIS)

Steinberg, M.

1982-01-01

A new nuclear fuel cycle is described which provides a long term supply of nuclear fuel for the thermal LWR nuclear power reactors and eliminates the need for long-term storage of radioactive waste. Fissile fuel is produced by the Spallator which depends on the production of spallation neutrons by the interaction of high-energy (1 to 2 GeV) protons on a heavy-metal target. The neutrons are absorbed in a surrounding natural-uranium or thorium blanket in which fissile Pu-239 to U-233 is produced. Advances in linear accelerator technology makes it possible to design and construct a high-beam-current continuous-wave proton linac for production purposes. The target is similar to a sub-critical reactor and produces heat which is converted to electricity for supplying the linac. The Spallator is a self-sufficient fuel producer, which can compete with the fast breeder. The APEX fuel cycle depends on recycling the transuranics and long-lived fission products while extracting the stable and short-lived fission products when reprocessing the fuel. Transmutation and decay within the fuel cycle and decay of short-lived fission products external to the fuel cycle eliminates the need for long-term geological age shortage of fission-product waste

Spallator and APEX nuclear fuel cycle: a new option for nuclear power

Energy Technology Data Exchange (ETDEWEB)

Steinberg, M.

1982-01-01

A new nuclear fuel cycle is described which provides a long term supply of nuclear fuel for the thermal LWR nuclear power reactors and eliminates the need for long-term storage of radioactive waste. Fissile fuel is produced by the Spallator which depends on the production of spallation neutrons by the interaction of high-energy (1 to 2 GeV) protons on a heavy-metal target. The neutrons are absorbed in a surrounding natural-uranium or thorium blanket in which fissile Pu-239 to U-233 is produced. Advances in linear accelerator technology makes it possible to design and construct a high-beam-current continuous-wave proton linac for production purposes. The target is similar to a sub-critical reactor and produces heat which is converted to electricity for supplying the linac. The Spallator is a self-sufficient fuel producer, which can compete with the fast breeder. The APEX fuel cycle depends on recycling the transuranics and long-lived fission products while extracting the stable and short-lived fission products when reprocessing the fuel. Transmutation and decay within the fuel cycle and decay of short-lived fission products external to the fuel cycle eliminates the need for long-term geological age shortage of fission-product waste.

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

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.

Qualification tests of materials for spallation neutron sources

International Nuclear Information System (INIS)

Sommer, W.F.; Maloy, S.; Wechsler, M.S.

1997-01-01

Several laboratories will take part in an extensive materials qualification program that includes irradiation in the proton beam and neutron field available at the Los Alamos Spallation Radiation Damage Facility (LASREF). A number of candidate materials will be exposed to prototypic spallation producing particle radiation. Studies of corrosion-related phenomena and the mitigation of these effects will also be accomplished

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.

Materials compatibility studies for the Spallation Neutron Source

International Nuclear Information System (INIS)

DiStefano, J.R.; Pawel, S.J.; Manneschmidt, E.T.

1998-01-01

The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation and hot, flowing mercury are all being addressed by R and D programs. In addition, corrosion studies also include evaluation of Inconel 718 because it has been successfully used in previous spallation neutron systems as a window material. Two types of compatibility issues relative to 316 SS/mercury and Inconel 718/mercury are being examined: (1) liquid metal embrittlement (LME) and (2) temperature gradient mass transfer. Studies have shown that mercury does not easily wet type 316 SS below 275 C. In the LME experiments, attempts were made to promote wetting of the steel by mercury either by adding gallium to the mercury or coating the specimen with a tin-silver solder that the mercury easily wets. The latter proved more reliable in establishing wetting, but there was no evidence of LME in any of the constant extension rate tensile tests either at 23 or 100 C. Inconel 718 also showed no change in room temperature properties when tested in mercury or mercury-gallium. However, there was evidence that the fracture was less ductile. Preliminary evaluation of mass transfer of either type 316 SS or Inconel 718 in mercury or mercury-gallium at 350 C (maximum temperature) did not reveal significant effects. Two 5,000 h thermal convection loop tests of type 316 SS are in progress, with specimens in both hot and cold test regions, at 300 and 240 C, respectively

Study of particle transport in a high power spallation target for an accelerator-driven transmutation system

International Nuclear Information System (INIS)

Shetty, Nikhil Vittal

2013-01-01

AGATE is a project envisaged to demonstrate the feasibility of transmutation in a gas (helium) cooled accelerator-driven system using solid spallation target. Development of the spallation target module and assessing its safety aspects are studied in this work. According to the AGATE concept parameters, 600 MeV protons are delivered on to the segmented tungsten spallation target. The Monte Carlo toolkit Geant4 has been used in the simulation of particle transport. Binary cascade is used to simulate intra-nuclear cascades, along with the G4NDL neutron data library for low energy neutrons (<20 MeV).

Study of particle transport in a high power spallation target for an accelerator-driven transmutation system

Energy Technology Data Exchange (ETDEWEB)

Shetty, Nikhil Vittal

2013-01-31

AGATE is a project envisaged to demonstrate the feasibility of transmutation in a gas (helium) cooled accelerator-driven system using solid spallation target. Development of the spallation target module and assessing its safety aspects are studied in this work. According to the AGATE concept parameters, 600 MeV protons are delivered on to the segmented tungsten spallation target. The Monte Carlo toolkit Geant4 has been used in the simulation of particle transport. Binary cascade is used to simulate intra-nuclear cascades, along with the G4NDL neutron data library for low energy neutrons (<20 MeV).

Detection of supernova neutrinos at spallation neutron sources

Science.gov (United States)

Huang, Ming-Yang; Guo, Xin-Heng; Young, Bing-Lin

2016-07-01

After considering supernova shock effects, Mikheyev-Smirnov-Wolfenstein effects, neutrino collective effects, and Earth matter effects, the detection of supernova neutrinos at the China Spallation Neutron Source is studied and the expected numbers of different flavor supernova neutrinos observed through various reaction channels are calculated with the neutrino energy spectra described by the Fermi-Dirac distribution and the “beta fit” distribution respectively. Furthermore, the numerical calculation method of supernova neutrino detection on Earth is applied to some other spallation neutron sources, and the total expected numbers of supernova neutrinos observed through different reactions channels are given. Supported by National Natural Science Foundation of China (11205185, 11175020, 11275025, 11575023)

Simulation of a high energy neutron irradiation facility at beamline 11 of the China Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Tairan, Liang [School of Physics and Electronic Information Inner Mongolia University for the Nationalities, Tongliao 028043 (China); Zhiduo, Li [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Wen, Yin, E-mail: wenyin@aphy.iphy.ac.cn [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Institute of Physics, CAS, P.O. Box 603, Beijing 100190 (China); Fei, Shen [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Quanzhi, Yu [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Institute of Physics, CAS, P.O. Box 603, Beijing 100190 (China); Tianjiao, Liang [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China)

2017-07-11

The China Spallation Neutron Source (CSNS) will accommodate 20 neutron beamlines at its first target station. These beamlines serve different purposes, and beamline 11 is designed to analyze the degraded models and damage mechanisms, such as Single Event Effects in electronic components and devices for aerospace electronic systems. This paper gives a preliminary discussion on the scheme of a high energy neutron irradiation experiment at the beamline 11 shutter based on the Monte Carlo simulation method. The neutron source term is generated by calculating the neutrons scattering into beamline 11 with a model that includes the target-moderator-reflector area. Then, the neutron spectrum at the sample position is obtained. The intensity of neutrons with energy of hundreds of MeV is approximately 1E8 neutron/cm{sup 2}/s, which is useful for experiments. The displacement production rate and gas productions are calculated for common materials such as tungsten, tantalum and SS316. The results indicate that the experiment can provide irradiation dose rate ranges from 1E-5 to 1E-4 dpa per operating year. The residual radioactivity is also calculated for regular maintenance work. These results give the basic reference for the experimental design.

Benchmarking shielding simulations for an accelerator-driven spallation neutron source

Directory of Open Access Journals (Sweden)

Nataliia Cherkashyna

2015-08-01

Full Text Available The shielding at an accelerator-driven spallation neutron facility plays a critical role in the performance of the neutron scattering instruments, the overall safety, and the total cost of the facility. Accurate simulation of shielding components is thus key for the design of upcoming facilities, such as the European Spallation Source (ESS, currently in construction in Lund, Sweden. In this paper, we present a comparative study between the measured and the simulated neutron background at the Swiss Spallation Neutron Source (SINQ, at the Paul Scherrer Institute (PSI, Villigen, Switzerland. The measurements were carried out at several positions along the SINQ monolith wall with the neutron dosimeter WENDI-2, which has a well-characterized response up to 5 GeV. The simulations were performed using the Monte-Carlo radiation transport code geant4, and include a complete transport from the proton beam to the measurement locations in a single calculation. An agreement between measurements and simulations is about a factor of 2 for the points where the measured radiation dose is above the background level, which is a satisfactory result for such simulations spanning many energy regimes, different physics processes and transport through several meters of shielding materials. The neutrons contributing to the radiation field emanating from the monolith were confirmed to originate from neutrons with energies above 1 MeV in the target region. The current work validates geant4 as being well suited for deep-shielding calculations at accelerator-based spallation sources. We also extrapolate what the simulated flux levels might imply for short (several tens of meters instruments at ESS.

Study of spallation neutrons for the transmutation of long-lived nuclear waste

International Nuclear Information System (INIS)

Brochard, F.; Boyard, J.L.; Duchazeaubeneix, J.C.; Durand, J.M.; Faivre, J.C.; Leray, S.; Milleret, G.; Plouin, F.; Whittal, D.M.; Beau, M.; Crespin, S.; Frehaut, J.; Lochard, J.P.; Martinez, E.; Patin, Y.; Petitbon, E.; Sigaud, J.; Legrain, R.; Lepretre, A.; Terrien, Y.; Bacha, F.; Maillard, J.; Silva, J.

1994-01-01

With the renewed interest in accelerator-driven systems to transmute long-lived nuclear waste or to produce energy, new requirements for intermediate-energy nuclear data are now emerging. In all these systems, neutrons are produced by spallation reactions induced by around 1 GeV protons on a heavy target. These neutrons then drive a sub-critical blanket in which wastes are burned or energy is produced. A good knowledge of the spallation process (energy and angular distribution of the neutrons) is necessary to design and optimize the target-blanket system: for instance, to determine the best choices of beam energy, of composition and geometry of the target, in order to have the maximum neutron yield at the lowest cost, or to minimize the back-scattering of neutrons to the accelerator. A programme aimed at measuring the double differential cross-sections for the production of spallation neutrons induced by protons and deuterons GeV beams on different targets, is beginning at SATURNE. (authors). 3 refs., 3 figs

Efficiency of an LBE spallation target in an accelerator-driven molten salt subcritical reactor

Energy Technology Data Exchange (ETDEWEB)

Bak, Sang-In [Sungkyunkwan University, Suwon (Korea, Republic of); Hong, Seung-Woo [Sungkyunkwan University, Suwon (Korea, Republic of); Kadi, Yacine [CERN, Geneva (Switzerland)

2016-10-15

An Accelerator-Driven System (ADS) combined with a subcritical Molten Salt Reactor (MSR) is a type of hybrid reactor originally designed to breed uranium from thorium or to incinerate long-lived minor actinides in nuclear wastes. In an MSR, the salt material is used not only as a nuclear fuel but also as a primary coolant. In addition, this material is used as a target for inducing spallation neutrons in most AD-MSR concepts. A high energy proton beam impinges on a heavy metal target to induce spallation reactions and produces neutrons. Accordingly, a reliable proton accelerator is needed to feed the source neutrons. As ADSs have been criticized for requiring high power accelerators, minimization of beam power is an important aspect of ADS design. A primary concern associated with ADS development is stable high-power accelerators. We therefore studied the neutron source efficiencies of an AD-MSR involving chloride fuels by including a Pb-Bi eutectic (LBE) spallation target. The proton source efficiency and the accelerator beam power required have been studied for an AD-MSR. Adoption of an LBE spallation target induces an increase in proton source efficiencies in comparison to the case without a spallation target. Thus the presence of an efficient spallation target is useful in the reduction of the beam power of an accelerator. Almost 33 % of the beam power can be reduced in comparison to the case without the target for NaCl-Th/{sup 233}U fuel, and about 16 % for NaCl-U/TRU fuel. The beam power amplifications increase by 1.5 times for NaCl-Th/{sup 233}U and 1.2 times for NaCl-U/TRU in comparison with the no target AD-MSR.

Investigation of the energy correlations of spallation neutrons by the MCNPX code

International Nuclear Information System (INIS)

Szieberth, Mate; Radocz, Gabor

2011-01-01

Earlier works have suggested that the energy correlations in a spallation source may influence the neutron noise measurements in an ADS. For the calculation of this effect not only the generally known and used one-particle spectrum is needed but also the so-called two particle spectrum, which describes also the energy correlations. Since measured data are not available for the energy distribution of the neutrons from a single spallation event the physical models of the MCNPX code have been used to investigate the effect. The calculational model has been successfully validated with measurements of the number distribution of spallation neutrons. The simulated one- and two-particle energy distributions and spectra proved that the energy correlations exist and have an important effect in low multiplicity spallation events and in thin targets. On the other hand for thick targets this effect appears negligible and the factorization of the two-particle spectrum seems an acceptable approximation. Further investigations are in hand to quantify the actual effect of the energy correlations on the neutron noise measurements. (author)

2. International workshop on spallation materials technology

International Nuclear Information System (INIS)

Carsughi, F.; Mansur, L.K.; Sommer, W.F.; Ullmaier, H.

1997-11-01

This document contains 25 papers consisting an abstract prepared by the authors, followed by copies of the presentation viewgraphs used by speakers. The topics were: Target options for SINQ; Overview of the NSNS target system; ISIS target and moderator materials; Trispal project; JHF N-ARENA; Design, load conditions and manufacturing aspect of the ESS MERCURY TARGET unit; Radiation damage simulatiion to measure recoil spectra distribution; Radiation damage calculation to spallation neutron source materials; Hadron-induced neutron production in Pb and U targets from 1-5 GeV; Proton beam effects on W rods, surface cooled by water; Corrosion and fatigue behavior of metals and alloys in high radiation fields; compability of materials with mercury for NSNS target system; Research activities at PSI on structural materials for spallation neutron source; The accelerator production of tritium materials reserach program and Los Alamos National Laboratory; Experimental program on irradiation effects in structural materials of the Trispal project; First pulsed power materials test at Livermore; Plan of thermal shock fracture test at JAERI; Is there a hydrogen problem in target materials in high-power spatllation source?; Materials consideration for the NSNS target; Materials durability issures in spallation neutron source applications; Post-irradiation investigations at the FZJ; Microstructure and hardening of steels containing high helium concentrations; Tensile properties and microstructure of the F82H ferritic-martensitic steel after irradiation in the PIREX facility

Spallation neutron production and the current intra-nuclear cascade and transport codes

International Nuclear Information System (INIS)

Filges, D.; Goldenbaum, F.

2001-01-01

A recent renascent interest in energetic proton-induced production of neutrons originates largely from the inception of projects for target stations of intense spallation neutron sources, like the planned European Spallation Source (ESS), accelerator-driven nuclear reactors, nuclear waste transmutation, and also from the application for radioactive beams. In the framework of such a neutron production, of major importance is the search for ways for the most efficient conversion of the primary beam energy into neutron production. Although the issue has been quite successfully addressed experimentally by varying the incident proton energy for various target materials and by covering a huge collection of different target geometries --providing an exhaustive matrix of benchmark data-- the ultimate challenge is to increase the predictive power of transport codes currently on the market. To scrutinize these codes, calculations of reaction cross-sections, hadronic interaction lengths, average neutron multiplicities, neutron multiplicity and energy distributions, and the development of hadronic showers are confronted with recent experimental data of the NESSI collaboration. Program packages like HERMES, LCS or MCNPX master the prevision of reaction cross-sections, hadronic interaction lengths, averaged neutron multiplicities and neutron multiplicity distributions in thick and thin targets for a wide spectrum of incident proton energies, geometrical shapes and materials of the target generally within less than 10% deviation, while production cross-section measurements for light charged particles on thin targets point out that appreciable distinctions exist within these models. (orig.)

Spallation neutron production and the current intra-nuclear cascade and transport codes

Science.gov (United States)

Filges, D.; Goldenbaum, F.; Enke, M.; Galin, J.; Herbach, C.-M.; Hilscher, D.; Jahnke, U.; Letourneau, A.; Lott, B.; Neef, R.-D.; Nünighoff, K.; Paul, N.; Péghaire, A.; Pienkowski, L.; Schaal, H.; Schröder, U.; Sterzenbach, G.; Tietze, A.; Tishchenko, V.; Toke, J.; Wohlmuther, M.

A recent renascent interest in energetic proton-induced production of neutrons originates largely from the inception of projects for target stations of intense spallation neutron sources, like the planned European Spallation Source (ESS), accelerator-driven nuclear reactors, nuclear waste transmutation, and also from the application for radioactive beams. In the framework of such a neutron production, of major importance is the search for ways for the most efficient conversion of the primary beam energy into neutron production. Although the issue has been quite successfully addressed experimentally by varying the incident proton energy for various target materials and by covering a huge collection of different target geometries --providing an exhaustive matrix of benchmark data-- the ultimate challenge is to increase the predictive power of transport codes currently on the market. To scrutinize these codes, calculations of reaction cross-sections, hadronic interaction lengths, average neutron multiplicities, neutron multiplicity and energy distributions, and the development of hadronic showers are confronted with recent experimental data of the NESSI collaboration. Program packages like HERMES, LCS or MCNPX master the prevision of reaction cross-sections, hadronic interaction lengths, averaged neutron multiplicities and neutron multiplicity distributions in thick and thin targets for a wide spectrum of incident proton energies, geometrical shapes and materials of the target generally within less than 10% deviation, while production cross-section measurements for light charged particles on thin targets point out that appreciable distinctions exist within these models.

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

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.

Experimental Study of the Phenomenology of Spallation Neutrons in a Large Lead Block

CERN Multimedia

Galvez Altamirano, J; Lopez, C; Perlado, J M; Perez-Navarro, A

2002-01-01

%PS211 %title \\\\ \\\\The purpose of PS211 is to determine how neutrons, produced by spallation inside a large Lead volume are slowed down by undergoing a very large number of scatterings, losing each time a small fraction ($\\sim$ 1\\%) of their kinetic energy. The focus is in determining the probability for a spallation neutron produced at an energy of several MeV or more, to survive capture on Lead resonances and to reach resonance energies of materials to be transmuted, such as 5.6 eV for $^{99}$Tc. This process, of Adiabatic Resonance Crossing, involves a subtle interplay between the capture resonances of the Lead medium and of selected impurities. This phenomenology of spallation neutrons in a large Lead volume, is the physics foundation of the Fast Energy Amplifier proposed by C. Rubbia, and could open up new possibilities in the incineration of long-lived nuclear waste such as Actinides or Fission Fragments (e.g. $^{99}$Tc, $^{129}$I, etc.).\\\\ \\\\334 tons of high purity Lead, installed in t7, are exposed to...

Modelling of an experiment for the study of neutron spallation source at JINR

International Nuclear Information System (INIS)

Kumawat, Harphool; Goyal, Uttam; Kumar, V.; Barashenkov, V.S.

2002-01-01

Intense neutron spallation source (INSS) is a necessary requirement of accelerator driven sub-critical systems. INSS are proposed to be generated using the high current proton beams. Some studies are conducted for the neutron flux, transmutation rates and energy gains and a larger number of related experiments are being planned

A comparison of microstructures in copper irradiated with fission, fusion, and spallation neutrons

International Nuclear Information System (INIS)

Muroga, T.; Heinisch, H.L.; Sommer, W.F.; Ferguson, P.D.

1992-01-01

The objective of this work is to investigate the effects of the neutron energy spectrum in low dose irradiations on the microstructure and mechanical properties of metals. The microstructures of pure copper irradiated to low doses at 36-90 C with spallation neutrons, fusion neutrons and fission neutrons are compared. The defect cluster densities for the spallation and fusion neutrons are very similar when compared on the basis of displacements per atom (dpa). In both cases, the density increases in proportion to the square root of the dpa. The difference in defect density between fusion neutrons and fission neutrons corresponds with differences observed in data on yield stress changes

Computational Benchmark Calculations Relevant to the Neutronic Design of the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Gallmeier, F.X.; Glasgow, D.C.; Jerde, E.A.; Johnson, J.O.; Yugo, J.J.

1999-01-01

The Spallation Neutron Source (SNS) will provide an intense source of low-energy neutrons for experimental use. The low-energy neutrons are produced by the interaction of a high-energy (1.0 GeV) proton beam on a mercury (Hg) target and slowed down in liquid hydrogen or light water moderators. Computer codes and computational techniques are being benchmarked against relevant experimental data to validate and verify the tools being used to predict the performance of the SNS. The LAHET Code System (LCS), which includes LAHET, HTAPE ad HMCNP (a modified version of MCNP version 3b), have been applied to the analysis of experiments that were conducted in the Alternating Gradient Synchrotron (AGS) facility at Brookhaven National Laboratory (BNL). In the AGS experiments, foils of various materials were placed around a mercury-filled stainless steel cylinder, which was bombarded with protons at 1.6 GeV. Neutrons created in the mercury target, activated the foils. Activities of the relevant isotopes were accurately measured and compared with calculated predictions. Measurements at BNL were provided in part by collaborating scientists from JAERI as part of the AGS Spallation Target Experiment (ASTE) collaboration. To date, calculations have shown good agreement with measurements

Study on bulk shielding for a spallation neutron source facility in the high-intensity proton accelerator project

CERN Document Server

Maekawa, F; Takada, H; Teshigawara, M; Watanabe, N

2002-01-01

Under the JAERI-KEK High-Intensity Proton Accelerator Project, a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed in a main part of the Materials and Life Science Facility. This report describes results of a study on bulk shielding performance of a biological shield for the spallation neutron source by means of a Monte Carlo calculation method, that is important in terms of radiation safety and cost reduction. A shielding configuration was determined as a reference case by considering preliminary studies and interaction with other components, then shielding thickness that was required to achieve a target dose rate of 1 mu Sv/h was derived. Effects of calculation conditions such as shielding materials and dimensions on the shielding performance was investigated by changing those parameters. By taking all the results and design margins into account, a shielding configuration that was identified as the most appropriate was finally determined as follows. An iron shield regi...

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)

Measurements of neutron spallation cross section. 2

Energy Technology Data Exchange (ETDEWEB)

Kim, E.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Imamura, M.; Nakao, N.; Shibata, S.; Uwamino, Y.; Nakanishi, N.; Tanaka, Su.

1997-03-01

Neutron spallation cross section of {sup 59}Co(n,xn){sup 60-x}Co, {sup nat}Cu(n,sp){sup 56}Mn, {sup nat}Cu(n,sp){sup 58}Co, {sup nat}Cu(n,xn){sup 60}Cu, {sup nat}Cu(n,xn){sup 61}Cu and {sup nat}Cu(n,sp){sup 65}Ni was measured in the quasi-monoenergetic p-Li neutron fields in the energy range above 40 MeV which have been established at three AVF cyclotron facilities of (1) INS of Univ. of Tokyo, (2) TIARA of JAERI and (3) RIKEN. Our experimental data were compared with the ENDF/B-VI high energy file data by Fukahori and the calculated cross section data by Odano. (author)

HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE

International Nuclear Information System (INIS)

SHAPIRO, S.M.; ZALIZNYAK, I.A.

2002-01-01

This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is an integral part, with a platform for ground-breaking investigations of the low-energy atomic-scale dynamical properties of crystalline solids. It is also planned that the proposed instrument will be equipped with a polarization analysis capability, therefore becoming the first polarized beam inelastic spectrometer in the SNS instrument suite, and the first successful polarized beam inelastic instrument at a pulsed spallation source worldwide. The proposed instrument is designed primarily for inelastic and elastic neutron spectroscopy of single crystals. In fact, the most informative neutron scattering studies of the dynamical properties of solids nearly always require single crystal samples, and they are almost invariably flux-limited. In addition, in measurements with polarization analysis the available flux is reduced through selection of the particular neutron polarization, which puts even more stringent limits on the feasibility of a particular experiment. To date, these investigations have mostly been carried out on crystal spectrometers at high-flux reactors, which usually employ focusing Bragg optics to concentrate the neutron beam on a typically small sample. Construction at Oak Ridge of the high-luminosity spallation neutron source, which will provide intense pulsed neutron beams with time-averaged fluxes equal to those at medium-flux reactors, opens entirely new opportunities for single crystal neutron spectroscopy. Drawing upon experience acquired during decades of studies with both crystal and time-of-flight (TOF) spectrometers, the IDT has developed a conceptual

HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE.

Energy Technology Data Exchange (ETDEWEB)

SHAPIRO,S.M.; ZALIZNYAK,I.A.

2002-12-30

This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is an integral part, with a platform for ground-breaking investigations of the low-energy atomic-scale dynamical properties of crystalline solids. It is also planned that the proposed instrument will be equipped with a polarization analysis capability, therefore becoming the first polarized beam inelastic spectrometer in the SNS instrument suite, and the first successful polarized beam inelastic instrument at a pulsed spallation source worldwide. The proposed instrument is designed primarily for inelastic and elastic neutron spectroscopy of single crystals. In fact, the most informative neutron scattering studies of the dynamical properties of solids nearly always require single crystal samples, and they are almost invariably flux-limited. In addition, in measurements with polarization analysis the available flux is reduced through selection of the particular neutron polarization, which puts even more stringent limits on the feasibility of a particular experiment. To date, these investigations have mostly been carried out on crystal spectrometers at high-flux reactors, which usually employ focusing Bragg optics to concentrate the neutron beam on a typically small sample. Construction at Oak Ridge of the high-luminosity spallation neutron source, which will provide intense pulsed neutron beams with time-averaged fluxes equal to those at medium-flux reactors, opens entirely new opportunities for single crystal neutron spectroscopy. Drawing upon experience acquired during decades of studies with both crystal and time-of-flight (TOF) spectrometers, the IDT has developed a conceptual

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

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.

Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

Energy Technology Data Exchange (ETDEWEB)

Mauro, N. A., E-mail: namauro@noctrl.edu [Department of Physics, North Central College, Naperville, Illinois 60540 (United States); Vogt, A. J. [Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Derendorf, K. S. [Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri 63130 (United States); Johnson, M. L.; Kelton, K. F. [Department of Physics and Institute of Materials Science and Engineering, Washington University, 1 Brookings Drive, St. Louis, Missouri 63130 (United States); Rustan, G. E.; Quirinale, D. G.; Goldman, A. I. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Kreyssig, A. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Division of Materials Sciences and Engineering, Ames Laboratory, Ames, Iowa 50011 (United States); Lokshin, K. A. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Neuefeind, J. C.; An, Ke [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Wang, Xun-Li [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Ave., Kowloon (Hong Kong); Egami, T. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Department of Physics and Astronomy, Joint Institute for Neutron Sciences, University of Tennessee, Knoxville, Tennessee 37996 (United States)

2016-01-15

Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. However, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr{sub 64}Ni{sub 36} measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample (∼100 mg)

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

Neutron Production by Muon Spallation I: Theory

International Nuclear Information System (INIS)

Luu, T; Hagmann, C

2006-01-01

We describe the physics and codes developed in the Muon Physics Package. This package is a self-contained Fortran90 module that is intended to be used with the Monte Carlo package MCNPX. We calculate simulated energy spectra, multiplicities, and angular distributions of direct neutrons and pions from muon spallation

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

Dynamically Polarized Sample for Neutron Scattering At the Spallation Neutron Source

International Nuclear Information System (INIS)

Pierce, Josh; Zhao, J. K.; Crabb, Don

2009-01-01

The recently constructed Spallation Neutron Source at the Oak Ridge National Laboratory is quickly becoming the world's leader in neutron scattering sciences. In addition to the world's most intense pulsed neutron source, we are continuously constructing state of the art neutron scattering instruments as well as sample environments to address today and tomorrow's challenges in materials research. The Dynamically Polarized Sample project at the SNS is aimed at taking maximum advantage of polarized neutron scattering from polarized samples, especially biological samples that are abundant in hydrogen. Polarized neutron scattering will allow us drastically increase the signal to noise ratio in experiments such as neutron protein crystallography. The DPS project is near completion and all key components have been tested. Here we report the current status of the project.

Irradiation facilities at the spallation neutron source SINQ

Energy Technology Data Exchange (ETDEWEB)

Lehmann, E.; Ledermann, J.; Aebersold, H.; Kuehne, G.; Kohlik, K. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-09-01

Four independent experiments for sample irradiation are under construction and in preparation for operational tests at the spallation source SINQ. Three of them are located inside a thermal beam port with end positions inside or near the moderator tank. The other experiment will be established at the end position of a super mirror lined neutron guide for applications with cold neutrons. (author) 3 figs., 1 tab., 6 refs.

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.

Department of Energy review of the National Spallation Neutron Source Project

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-06-01

A Department of Energy (DOE) review of the Conceptual Design Report (CDR) for the National Spallation Neutron Source (NSNS) was conducted. The NSNS will be a new high-power spallation neutron source; initially, it will operate at 1 megawatt (MW), but is designed to be upgradeable to significantly higher power, at lower cost, when accelerator and target technologies are developed for higher power. The 53-member Review Committee examined the projected cost, schedule, technical scope, and management structure described in the CDR. For each of the major components of the NSNS, the Committee determined that the project team had produced credible designs that can be expected to work well. What remains to be done is to integrate the design of these components. With the exception of the liquid mercury target, the NSNS Project will rely heavily on proven technologies and, thus, will face a relatively low risk to successful project completion. The Total Project Cost (TPC) presented to the Committee in the CDR was $1.266 billion in as-spent dollars. In general, the Committee felt that the laboratory consortium had presented a credible estimate for each of the major components but that value engineering might produce some savings. The construction schedule presented to the Committee covered six years beginning in FY 1999. The Committee questioned whether all parts of the project could be completed according to this schedule. In particular, the linac and the conventional facilities appeared to have overly optimistic schedules. The NSNS project team was encouraged to reexamine these activities and to consider a more conservative seven-year schedule. Another concern of the Committee was the management structure. In summary, the Committee felt that this Conceptual Design Report was a very credible proposal, and that there is a high probability for successful completion of this major project within the proposed budget, although the six-year proposed schedule may be optimistic.

Department of Energy review of the National Spallation Neutron Source Project

International Nuclear Information System (INIS)

1997-06-01

A Department of Energy (DOE) review of the Conceptual Design Report (CDR) for the National Spallation Neutron Source (NSNS) was conducted. The NSNS will be a new high-power spallation neutron source; initially, it will operate at 1 megawatt (MW), but is designed to be upgradeable to significantly higher power, at lower cost, when accelerator and target technologies are developed for higher power. The 53-member Review Committee examined the projected cost, schedule, technical scope, and management structure described in the CDR. For each of the major components of the NSNS, the Committee determined that the project team had produced credible designs that can be expected to work well. What remains to be done is to integrate the design of these components. With the exception of the liquid mercury target, the NSNS Project will rely heavily on proven technologies and, thus, will face a relatively low risk to successful project completion. The Total Project Cost (TPC) presented to the Committee in the CDR was $1.266 billion in as-spent dollars. In general, the Committee felt that the laboratory consortium had presented a credible estimate for each of the major components but that value engineering might produce some savings. The construction schedule presented to the Committee covered six years beginning in FY 1999. The Committee questioned whether all parts of the project could be completed according to this schedule. In particular, the linac and the conventional facilities appeared to have overly optimistic schedules. The NSNS project team was encouraged to reexamine these activities and to consider a more conservative seven-year schedule. Another concern of the Committee was the management structure. In summary, the Committee felt that this Conceptual Design Report was a very credible proposal, and that there is a high probability for successful completion of this major project within the proposed budget, although the six-year proposed schedule may be optimistic

Nondiffractive applications of neutrons at the spallation source SINQ

International Nuclear Information System (INIS)

Lehmann, E.

1996-01-01

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

Nondiffractive applications of neutrons at the spallation source SINQ

Energy Technology Data Exchange (ETDEWEB)

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

1996-11-01

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

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

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

Invited talks (Abstracts only) The spallation neutron source: New ...

Indian Academy of Sciences (India)

The spallation neutron source (SNS) facility became operational in the spring of 2006, and is ... torate at ORNL providing the opportunity to develop science and instrumentation pro- ... tion, information technology, biotechnology, and health.

SUPERCONDUCTING LINAC FOR THE SPALLATION NEUTRON SOURCE

International Nuclear Information System (INIS)

STOVALL, J.; NATH, S.

2000-01-01

The Spallation Neutron Source (SNS) linac is comprised of both normal and superconducting rf (SRF) accelerating structures. The SRF linac accelerates the beam from 186 to 1250 MeV through 117 elliptical, multi-cell niobium cavities. This paper describes the SRF linac architecture, physics design considerations, cavity commissioning, and the expected beam dynamics performance

Evaluation of the transmutation of transuranic using neutrons spectrum from the spallation reaction

Energy Technology Data Exchange (ETDEWEB)

Gilberti, Mauricio; Pereira, Claubia, E-mail: mgilber@eletronuclear.gov.br [Eletrobras Termonuclear S.A. (ELETRONUCLEAR), Angra dos Reis, RJ (Brazil); Veloso, Maria A. Fortini, E-mail: claubia@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizante, MG (Brazil). Dept. de Engenharia Nuclear

2013-07-01

The transmutation of transuranic was analyzed by simulating the neutron flux from different spallation sources across arrays of fissile material with isotopic composition PWR reprocessing. A simplified model of Accelerator-Driven Systems (ADS) containing target, moderator graphite, lead-bismuth coolant or sodium coolant, is used. The simulation was made using the particles transport code MCNPX 2.6.0 which allowed to evaluate the rate of transmutation of actinides (Np, Pu, Am, and Cm) at different locations in the system. The objective of the study is to evaluate which the behavior and influences the spectrum of the spallation in the transmutation without the contribution or interference of multiplier, medium subcritical, which would add the contribution of fission neutrons generated, thus interfering in the analysis. The arrangement enable to infer the influence of hardened neutron flux from the spallation reaction in the transmutation, the results show that this is independent of the target material chosen, and the spectrum of spallation has a negligible importance compared to the influence of moderation and scattering generated by the coolant or moderator used. (author)

Evaluation of the transmutation of transuranic using neutrons spectrum from the spallation reaction

International Nuclear Information System (INIS)

Gilberti, Mauricio; Pereira, Claubia; Veloso, Maria A. Fortini

2013-01-01

The transmutation of transuranic was analyzed by simulating the neutron flux from different spallation sources across arrays of fissile material with isotopic composition PWR reprocessing. A simplified model of Accelerator-Driven Systems (ADS) containing target, moderator graphite, lead-bismuth coolant or sodium coolant, is used. The simulation was made using the particles transport code MCNPX 2.6.0 which allowed to evaluate the rate of transmutation of actinides (Np, Pu, Am, and Cm) at different locations in the system. The objective of the study is to evaluate which the behavior and influences the spectrum of the spallation in the transmutation without the contribution or interference of multiplier, medium subcritical, which would add the contribution of fission neutrons generated, thus interfering in the analysis. The arrangement enable to infer the influence of hardened neutron flux from the spallation reaction in the transmutation, the results show that this is independent of the target material chosen, and the spectrum of spallation has a negligible importance compared to the influence of moderation and scattering generated by the coolant or moderator used. (author)

Overcoming High Energy Backgrounds at Pulsed Spallation Sources

CERN Document Server

Cherkashyna, Nataliia; DiJulio, Douglas D.; Khaplanov, Anton; Pfeiffer, Dorothea; Scherzinger, Julius; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Ansell, Stuart; Iverson, Erik B.; Ehlers, Georg; Gallmeier, Franz X.; Panzner, Tobias; Rantsiou, Emmanouela; Kanaki, Kalliopi; Filges, Uwe; Kittelmann, Thomas; Extegarai, Maddi; Santoro, Valentina; Kirstein, Oliver; Bentley, Phillip M.

2015-01-01

Instrument backgrounds at neutron scattering facilities directly affect the quality and the efficiency of the scientific measurements that users perform. Part of the background at pulsed spallation neutron sources is caused by, and time-correlated with, the emission of high energy particles when the proton beam strikes the spallation target. This prompt pulse ultimately produces a signal, which can be highly problematic for a subset of instruments and measurements due to the time-correlated properties, and different to that from reactor sources. Measurements of this background have been made at both SNS (ORNL, Oak Ridge, TN, USA) and SINQ (PSI, Villigen, Switzerland). The background levels were generally found to be low compared to natural background. However, very low intensities of high-energy particles have been found to be detrimental to instrument performance in some conditions. Given that instrument performance is typically characterised by S/N, improvements in backgrounds can both improve instrument pe...

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)

Spallation production of neutron deficient radioisotopes in North America

International Nuclear Information System (INIS)

Jamriska, D.J.; Peterson, E.J.; Carty, J.

1997-01-01

The United States Department of Energy produces a number of neutron deficient radioisotopes by high energy proton induced spallation reactions in accelerators at Los Alamos National Laboratory in New Mexico and Brookhaven National Laboratory in New York. Research isotopes are also recovered from targets irradiated at TRIUMF in British Columbia, Canada. The radioisotopes recovered are distributed for use in nuclear medicine, environmental research, physics research, and industry worldwide. In addition to the main product line of Sr-82 from either Mo or Rb targets, Cu-67 from ZnO targets, and Ge-68 from RbBr targets, these irradiation facilities also produce some unique isotopes in quantities not available from any other source such as Be-10, Al-26, Mg-28, Si-32, El-44, Fe-52, Gd-248, and Hg-194. We will describe the accelerator irradiation facilities at the Los Alamos and Brookhaven National Laboratories. The high level radiochemical processing facilities at Los Alamos and brief chemical processes from Los Alamos and Brookhaven will be described. Chemical separation techniques have been developed to recover the radioisotopes of interest in both high radiochemical purity and yield and at the same time trying to reduce or eliminate the generation of mixed waste. nearly 75 neutron deficient radioisotopes produced in spallation targets have been produced and distributed to researchers around the world since the inception of the program in 1974

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

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

Tensile property changes of metals and irradiated to low doses with fission, fusion and spallation neutrons

International Nuclear Information System (INIS)

Heinisch, H.L.; Hamilton, M.L.; Sommer, W.F.; Ferguson, P.D.

1992-01-01

The objective of this work is to investigate the effects of the neutron energy spectrum in low dose irradiations on the microstructures and mechanical properties of metals. Radiation effects due to low doses of spallation neutrons are compared directly to those produced by fission and fusion neutrons. Yield stress changes of pure Cu, alumina-dispersion-strengthened Cu and AISI 316 stainless steel irradiated at 36-55 C in the Los Alamos Spallation Radiation Effects Facility (LASREF) are compared with earlier results of irradiations at 90 C using 14 MeV D-T fusion neutrons at the Rotating Target Neutron Source and fission reactor neutrons in the Omega West Reactor. At doses up to 0.04 displacements per atom (dpa), the yield stress changes due to the three quite different neutron spectra correlate well on the basis of dpa in the stainless steel and the Cu alloy. However, in pure Cu, the measured yield stress changes due to spallation neutrons were anomalously small and should be verified by additional irradiations. With the exception of pure Cu, the low dose, low temperature experiments reveal no fundamental differences in radiation hardening by fission, fusion or spallation neutrons when compared on the basis of dpa

Device for Writing the Time Tail from Spallation Neutron Pulses

International Nuclear Information System (INIS)

Langan, P.; Schoenborn, Benno P.; Daemen, L.L.

2001-01-01

Recent work at Los Alamos Neutron Science Center (LANSCE), has shown that there are large gains in neutron beam intensity to be made by using coupled moderators at spallation neutron sources. Most of these gains result from broadening the pulse-width in time. However the accompanying longer exponential tail at large emission times can be a problem in that it introduces relatively large beam-related backgrounds at high resolutions. We have designed a device that can reshape the moderated neutron beam by cutting the time-tail so that a sharp time resolution can be re-established without a significant loss in intensity. In this work the basic principles behind the tail-cutter and some initial results of Monte Carlo simulations are described. Unwanted neutrons in the long time-tail are diffracted out of the transmitted neutron beam by a nested stack of aperiodic multi-layers, rocking at the same frequency as the source. Nested aperiodic multi-layers have recently been used at X-ray sources and as band-pass filters in quasi-Laue neutron experiments at reactor neutron sources. Optical devices that rock in synchronization with a pulsed neutron beam are relatively new but are already under construction at LANSCE. The tail-cutter described here is a novel concept that uses existing multi-layer technology in a new way for spallation neutrons. Coupled moderators in combination with beam shaping devices offer the means of increasing flux whilst maintaining a sharp time distribution. A prototype device is being constructed for the protein crystallography station at LANSCE. The protein crystallography station incorporates a water moderator that has been judiciously coupled in order to increase the flux over neutron energies that are important to structural biology (3-80meV). This development in moderator design is particularly important because protein crystallography is flux limited and because conventional ambient water and cold hydrogen moderators do not provide relatively

Los Alamos high-power proton linac designs

Energy Technology Data Exchange (ETDEWEB)

Lawrence, G.P. [Los Alamos National Laboratory, NM (United States)

1995-10-01

Medium-energy high-power proton linear accelerators have been studied at Los Alamos as drivers for spallation neutron applications requiring large amounts of beam power. Reference designs for such accelerators are discussed, important design factors are reviewed, and issues and concern specific to this unprecedented power regime are discussed.

Safety techniques in the change of nuclear systems. Radiation protection at spallation neutron sources and transmutation facilities; Sicherheitstechnik im Wandel Nuklearer Systeme. Strahlenschutz bei Spallationsneutronenquellen und Transmutationsanlagen

Energy Technology Data Exchange (ETDEWEB)

Nuenighoff, Kay

2009-07-01

To push the boundary towards higher neutron fluxes concepts based on spallation reactions have been discussed. Here neutrons are produced by bombarding a heavy metal target (e.g. mercury, tungsten, or tantalum) with high energetic protons. Up to now such facilities could not be realised because of the high power particle accelerators needed. Recent developments of the accelerator technology open the possibility of construction and operating proton accelerators in the MW region. This is demonstrated by construction and commissioning of two MW spallation neutron sources, namely SNS (Oak Ridge, Tennessee, USA) with a power of 1.4 MW and J-PARC (Japan) with 1 MW. The realisation of proton accelerators at this power level will open the way towards energy amplifiers, as proposed e.g. by Carlo Rubbia. Such a facility will not only produce electric power. Furthermore longliving radionuclides can be transmutated into shortlived or even stable nuclides by neutron induced nuclear reactions. A mitigation of the problem of nuclear waste disposal. The above discussed developments prove that accelerators are not only constructed for research, moreover application of these technology became state of the art. With the emergence of particle accelerators in the MW region, radiation protection is confronted with new kind of problems to be solved. Especially the higher kinetic energies of the primary beam particles requires modification and expansion of computer programs well known in nuclear engineering. In contrast to nuclear reactors with kinetic energies up to 2-3 MeV, in spallation reaction secondary particles up to the incident energy in the GeV region will be produced. Problems related to radiation protection have to be considered in an energy range three orders of magnitude higher than known from nuclear reactors. In this thesis existing computer codes are compared and validated with data from selected experiments. Questions concerning radiation protection covers a broad range

Facility for fast neutron irradiation tests of electronics at the ISIS spallation neutron source

International Nuclear Information System (INIS)

Andreani, C.; Pietropaolo, A.; Salsano, A.; Gorini, G.; Tardocchi, M.; Paccagnella, A.; Gerardin, S.; Frost, C. D.; Ansell, S.; Platt, S. P.

2008-01-01

The VESUVIO beam line at the ISIS spallation neutron source was set up for neutron irradiation tests in the neutron energy range above 10 MeV. The neutron flux and energy spectrum were shown, in benchmark activation measurements, to provide a neutron spectrum similar to the ambient one at sea level, but with an enhancement in intensity of a factor of 10 7 . Such conditions are suitable for accelerated testing of electronic components, as was demonstrated here by measurements of soft error rates in recent technology field programable gate arrays

The Spallation Neutron Source RF Reference System

CERN Document Server

Piller, Maurice; Crofford, Mark; Doolittle, Lawrence; Ma, Hengjie

2005-01-01

The Spallation Neutron Source (SNS) RF Reference System includes the master oscillator (MO), local oscillator(LO) distribution, and Reference RF distribution systems. Coherent low noise Reference RF signals provide the ability to control the phase relationships between the fields in the front-end and linear accelerator (linac) RF cavity structures. The SNS RF Reference System requirements, implementation details, and performance are discussed.

Accumulator ring lattice for the national spallation neutron source

International Nuclear Information System (INIS)

Gardner, C.J.; Lee, Y.Y.; Luccio, A.U.

1997-01-01

The Accumulator Ring for the proposed National Spallation Neutron Source (NSNS) is to accept a 1.03 millisecond beam pulse from a 1 GeV Proton Linac at a repetition rate of 60 Hz. For each beam pulse, 10 14 protons are to be accumulated via charge-exchange injection. A 295 nanosecond gap in the beam, maintained by an rf system, will allow for extraction to an external target for the production of neutrons by spallation. This paper describes the four-fold symmetric lattice that has been chosen for the ring. The lattice contains four long dispersion-free straight sections to accomodate injection, extraction, rf cavities, and beam scraping respectively. The four-fold symmetry allows for easy adjustment of the tunes and flexibility in the placement of correction elements, and ensures that potentially dangerous betatron structure resonances are avoided

Results from the TARC experiment: spallation neutron phenomenology in lead and neutron-driven nuclear transmutation by adiabatic resonance crossing.

CERN Document Server

Abánades, A; Andriamonje, Samuel A; Angelopoulos, Angelos; Apostolakis, Alcibiades J; Arnould, H; Belle, E; Bompas, C A; Brozzi, Delecurgo; Bueno, J; Buono, S; Carminati, F; Casagrande, Federico; Cennini, P; Collar, J I; Cerro, E; Del Moral, R; Díez, S; Dumps, Ludwig; Eleftheriadis, C; Embid, M; Fernández, R; Gálvez, J; García, J; Gelès, C; Giorni, A; González, E; González, O; Goulas, I; Heuer, R D; Hussonnois, M; Kadi, Y; Karaiskos, P; Kitis, G; Klapisch, Robert; Kokkas, P; Lacoste, V; Le Naour, C; Lèpez, C; Loiseaux, J M; Martínez-Val, J M; Méplan, O; Nifenecker, H; Oropesa, J; Papadopoulos, I M; Pavlopoulos, P; Pérez-Enciso, E; Pérez-Navarro, A; Perlado, M; Placci, A; Poza, M; Revol, Jean Pierre Charles; Rubbia, Carlo; Rubio, J A; Sakelliou, L; Saldaña, F; Savvidis, E; Schussler, F; Sirvent, C; Tamarit, J; Trubert, D; Tzima, A; Viano, J B; Vieira, S L; Vlachoudis, V; Zioutas, Konstantin; CERN. Geneva. SPS and LEP Division

2000-01-01

The results of the TARC experiment are summarized herewith, whose main purpose is to demonstrate the possibility of using Adiabatic Resonance Crossing (ARC) to destroy efficiently Long-Lived Fission Fragments (LLFFs) in accelerator-driven systems and to validate a new simulation developed in the framework of the Energy Amplifier programme. An experimental set-up was installed in a CERN PS proton beam line to study how neutrons, produced by spallation at relatively high energy (En * 1 MeV), slow down quasi adiabatically, with almost flat isolethargic energy distribution and reach the capture resonance energy of an element to be transmuted where they will have a high probability of being captured. Precision measurements of energy and space distributions of spallation neutrons (using 2.5 GeV/c and 3.5 GeV/c protons) slowing down in a 3.3 m x 3.3 m x 3 m lead volume and of neutron capture rates on LLFFs 99Tc, 129I, and several other elements were performed. An appropriate formalism and appropriate computational t...

Mercury purification in the megawatt liquid metal spallation target of EURISOL-DS

CERN Document Server

Neuhausen, Joerg; Eller, Martin; Schumann, Dorothea; Eichler, Bernd; Horn, Susanne

High power spallation targets are going to be used extensively in future research and technical facilities such as spallation neutron sources, neutrino factories, radioactive beam facilities or accelerator driven systems for the transmutation of long-lived nuclear waste. Within EURISOL-DS, a 4 MW liquid metal spallation target is designed to provide neutrons for a fission target, where neutron rich radionuclides will be produced. For the spallation target, mercury is planned to be used as target material. A large amount of radionuclides ranging from atomic number Z=1 to 81 will be produced in the liquid metal during long term irradiation. It is planned to remove those radionuclides by chemical or physicochemical methods to reduce its radioactivity. For the development of a purification procedure, knowledge about the chemical state of the different elements present in the mixture is required. We present a general concept of applicable separation techniques in a target system and show some results of experiment...

Triple GEM gas detectors as real time fast neutron beam monitors for spallation neutron sources

International Nuclear Information System (INIS)

Murtas, F; Claps, G; Croci, G; Tardocchi, M; Pietropaolo, A; Cippo, E Perelli; Rebai, M; Gorini, G; Frost, C D; Raspino, D; Rhodes, N J; Schooneveld, E M

2012-01-01

A fast neutron beam monitor based on a triple Gas Electron Multiplier (GEM) detector was developed and tested for the ISIS spallation neutron source in U.K. The test on beam was performed at the VESUVIO beam line operating at ISIS. The 2D fast neutron beam footprint was recorded in real time with a spatial resolution of a few millimeters thanks to the patterned detector readout.

Cooperative effort between Consorcio European Spallation Source--Bilbao and Oak Ridge National Laboratory spallation neutron source for manufacturing and testing of the JEMA-designed modulator system

Energy Technology Data Exchange (ETDEWEB)

Anderson, David E [ORNL

2017-01-02

The JEMA modulator was originally developed for the European Spallation Source (ESS) when Spain was under consideration as a location for the ESS facility. Discussions ensued and the Spallation Neutron Source Research Accelerator Division agreed to form a collaboration with ESS-Bilbao (ESS-B) consortium to provide services for specifying the requirements for a version of the modulator capable of operating twelve 550 kW klystrons, monitoring the technical progress on the contract with JEMA, installing and commissioning the modulator at SNS, and performing a 30 day full power test. This work was recently completed, and this report discusses those activities with primary emphasis on the installation and testing activities.

Cooperative effort between Consorcio European Spallation Source--Bilbao and Oak Ridge National Laboratory spallation neutron source for manufacturing and testing of the JEMA-designed modulator system

International Nuclear Information System (INIS)

Anderson, David E.

2017-01-01

The JEMA modulator was originally developed for the European Spallation Source (ESS) when Spain was under consideration as a location for the ESS facility. Discussions ensued and the Spallation Neutron Source Research Accelerator Division agreed to form a collaboration with ESS-Bilbao (ESS-B) consortium to provide services for specifying the requirements for a version of the modulator capable of operating twelve 550 kW klystrons, monitoring the technical progress on the contract with JEMA, installing and commissioning the modulator at SNS, and performing a 30 day full power test. This work was recently completed, and this report discusses those activities with primary emphasis on the installation and testing activities.

The Prototype Fundamental Power Coupler For The Spallation Neutron Source Superconducting Cavities: Design And Initial Test Results

International Nuclear Information System (INIS)

K. M. Wilson; I. E. Campisi; E. F. Daly; G. K. Davis; M. Drury; J. E. Henry; P. Kneisel; G. Myneni; T. Powers; W. J. Schneider; M. Stirbet; Y. Kang; K. Cummings; T. Hardek

2001-01-01

Each of the 805 MHz superconducting cavities of the Spallation Neutron Source (SNS) is powered via a coaxial Fundamental Power Coupler (FPC) with a 50 Omega impedance and a warm planar alumina window. The design is derived from the experience of other laboratories; in particular, a number of details are based on the coupler developed for the KEK B-Factory superconducting cavities. However, other design features have been modified to account for the fact that the SNS FPC will transfer a considerably lower average power than the KEK-B coupler. Four prototypes have been manufactured so far, and preliminary tests performed on two of them at Los Alamos National Laboratory (LANL). During these tests, peak powers of over 500 kW were transferred through the couplers in the test stand designed and built for this purpose. This paper gives details of the coupler design and of the results obtained from the RF tests on the test stand during the last few months. A more comprehensive set of tests is planned for the near future

A Long-Pulse Spallation Source at Los Alamos: Facility description and preliminary neutronic performance for cold neutrons

International Nuclear Information System (INIS)

Russell, G.J.; Weinacht, D.J.; Pitcher, E.J.; Ferguson, P.D.

1998-03-01

The Los Alamos National Laboratory has discussed installing a new 1-MW spallation neutron target station in an existing building at the end of its 800-MeV proton linear accelerator. Because the accelerator provides pulses of protons each about 1 msec in duration, the new source would be a Long Pulse Spallation Source (LPSS). The facility would employ vertical extraction of moderators and reflectors, and horizontal extraction of the spallation target. An LPSS uses coupled moderators rather than decoupled ones. There are potential gains of about a factor of 6 to 7 in the time-averaged neutron brightness for cold-neutron production from a coupled liquid H 2 moderator compared to a decoupled one. However, these gains come at the expense of putting ''tails'' on the neutron pulses. The particulars of the neutron pulses from a moderator (e.g., energy-dependent rise times, peak intensities, pulse widths, and decay constant(s) of the tails) are crucial parameters for designing instruments and estimating their performance at an LPSS. Tungsten is the reference target material. Inconel 718 is the reference target canister and proton beam window material, with Al-6061 being the choice for the liquid H 2 moderator canister and vacuum container. A 1-MW LPSS would have world-class neutronic performance. The authors describe the proposed Los Alamos LPSS facility, and show that, for cold neutrons, the calculated time-averaged neutronic performance of a liquid H 2 moderator at the 1-MW LPSS is equivalent to about 1/4th the calculated neutronic performance of the best liquid D 2 moderator at the Institute Laue-Langevin reactor. They show that the time-averaged moderator neutronic brightness increases as the size of the moderator gets smaller

Disposal strategy of proton irradiated mercury from high power spallation sources

International Nuclear Information System (INIS)

Chiriki, Suresh

2010-01-01

Large spallation sources are intended to be constructed in Europe (EURISOL: nuclear physics research facility and ESS: European Spallation Source). These facilities would accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Liquid waste cannot be tolerated in European repositories. As part of this work on safety/decommissioning of high-power spallation sources, our investigations were focused mainly to study experimentally and theoretically the solidification of liquid mercury waste (selection of an adequate solid mercury form and of an immobilization matrix, chemical engineering process studies on solidification/stabilization and on encapsulating in a matrix). Based on experimental results and supported by literature Hg-chalcogens (HgS, HgSe) will be more stable in repositories than amalgams. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in possible accidents with water ingress in a repository. Additionally immobilization of mercury in a cement matrix and polysiloxane matrix were tested. HgS formation from liquid target mercury by a wet process is identified as a suitable formation procedure. These investigations reveal that an almost 99.9% elementary Hg conversion can be achieved and that wet process can be reasonably handled under hot cell conditions. (orig.)

Disposal strategy of proton irradiated mercury from high power spallation sources

Energy Technology Data Exchange (ETDEWEB)

Chiriki, Suresh

2010-07-01

Large spallation sources are intended to be constructed in Europe (EURISOL: nuclear physics research facility and ESS: European Spallation Source). These facilities would accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Liquid waste cannot be tolerated in European repositories. As part of this work on safety/decommissioning of high-power spallation sources, our investigations were focused mainly to study experimentally and theoretically the solidification of liquid mercury waste (selection of an adequate solid mercury form and of an immobilization matrix, chemical engineering process studies on solidification/stabilization and on encapsulating in a matrix). Based on experimental results and supported by literature Hg-chalcogens (HgS, HgSe) will be more stable in repositories than amalgams. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in possible accidents with water ingress in a repository. Additionally immobilization of mercury in a cement matrix and polysiloxane matrix were tested. HgS formation from liquid target mercury by a wet process is identified as a suitable formation procedure. These investigations reveal that an almost 99.9% elementary Hg conversion can be achieved and that wet process can be reasonably handled under hot cell conditions. (orig.)

Spallation neutron spectra measured at Saturne

International Nuclear Information System (INIS)

Boyard, J.L.; Bouyer, P.; Brochard, F.; Duchazeaubeneix, J.C.; Durand, J.M.; Leray, S.; Milleret, G.; Plouin, F.; Uematsu, M.; Whittal, D.M.; Martinez, E.; Beau, M.; Boue, F.; Crespin, S.; Drake, D.; Frehaut, J.; Lochard, J.P.; Patin, Y.; Petibon, E.; Legrain, R.; Terrien, Y.

1995-01-01

Good knowledge of spallation reactions is necessary to design accelerator-based transmutation systems. An extensive program has begun at Saturne to measure energy and angular distributions of neutrons produced by incident protons or deuterons of up to 2 GeV on several thin targets. Our measurements will extend the available data to higher energies than the present limit of 800 MeV enabling improvements to the codes which are sometimes in poor agreement with the data. (Authors). 7 refs., 7 figs

Calculation of displacement, gas, and transmutation production in stainless steel irradiated with spallation neutrons

International Nuclear Information System (INIS)

Wechsler, M.A.; Ramavarapu, R.; Daugherty, E.L.; Palmer, R.C.; Bullen, D.B.; Sommer, W.F.

1993-01-01

Calculations using the high-energy transport code LAHET have been made for the production of displacements, helium gas, and transmuted atoms for stainless steel (Fe-18 wt % Cr-10 wt % Ni) irradiated with spallation neutrons at energies of 100 to 1600 MeV. The damage energy cross section increased from about 250 to 350 b keV for increasing neutron energies from 100 to 1600 MeV with a spallation spectrum average of 281 barns-keV. For a displacement threshold energy of 33 eV, the corresponding spectrum-average displacement cross section is 3400 barns. The PKA spectrum was found to be fairly independent of the incident neutron energy, with an average damage energy of 0.25--0.30 MeV. The helium production cross section increased monotonically with increasing neutron energy, with a spectrum average of 0.32 barns. The maximum transmutation yield was observed near manganese (Z = 25), corresponding to a production cross section of about 0.2 barns. Relevance to fusion materials is discussed

Accelerator system of neutron spallation source for nuclear energy technology development

International Nuclear Information System (INIS)

Silakhuddin; Mulyaman, Maman

2002-01-01

High intensity proton accelerators are at present and developed for applications in neutron spallation sources. The advantages of this source are better safety factor, easy in controlling and spent fuel free. A study of conceptual design of required accelerator system has been carried out. Considering the required proton beam and feasibility in the development stages, a stepped linac system is an adequate choice for now

Characteristics of the WNR: a pulsed spallation neutron source

International Nuclear Information System (INIS)

Russell, G.J.; Lisowski, P.W.; Howe, S.D.; King, N.S.P.; Meier, M.M.

1982-01-01

The Weapons Neutron Research facility (WNR) is a pulsed spallation neutron source in operation at the Los Alamos National Laboratory. The WNR uses part of the 800-MeV proton beam from the Clinton P. Anderson Meson Physics Facility accelerator. By choosing different target and moderator configurations and varying the proton pulse structure, the WNR can provide a white neutron source spanning the energy range from a few MeV to 800 MeV. The neutron spectrum from a bare target has been measured and is compared with predictions using an Intranuclear Cascade model coupled to a Monte Carlo transport code. Calculations and measurements of the neutronics of WNR target-moderator assemblies are presented

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

Science.gov (United States)

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

2012-02-01

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

Stabilized operation of the Spallation Neutron Source radio-frequency quadrupole

Directory of Open Access Journals (Sweden)

Sang-ho Kim

2010-07-01

Full Text Available The Spallation Neutron Source (SNS radio-frequency quadrupole (RFQ had resonance control instabilities at duty factors higher than approximately 4%. Systematic investigations have been carried out to understand the cause of the instability and to ensure the operational stability of the RFQ. The most critical source of the instability is revealed to be an interaction between hydrogen released by beam bombardments and the RFQ rf field resulting in a discharge, which consumes additional rf power and could cause the RFQ to operate in an unstable region. This paper reports improvement of the SNS RFQ operational stability based on the findings during the SNS operation.

Shielding concerns at a spallation source

International Nuclear Information System (INIS)

Russell, G.J.; Robinson, H.; Legate, G.L.; Woods, R.

1989-01-01

Neutrons produced by 800-MeV proton reactions at the Los Alamos Neutron Scattering Center spallation neutron source cause a variety of challenging shielding problems. We identify several characteristics distinctly different from reactor shielding and compute the dose attenuation through an infinite slab/shield composed of iron (100 cm) and borated polyethylene (15 cm). Our calculations show that (for an incident spallation spectrum characteristic of neutrons leaking from a tungsten target at 90/degree/) the dose through the shield is a complex mixture of neutrons and gamma rays. High-energy (> 20 MeV) neutron production from the target is ≅5% of the total, yet causes ≅68% of the dose at the shield surface. Primary low-energy (< 20 MeV) neutrons from the target contribute negligibly (≅0.5%) to the dose at the shield surface yet cause gamma rays, which contribute ≅31% to the total dose at the shield surface. Low-energy neutrons from spallation reactions behave similarly to neutrons with a fission spectrum distribution. 6 refs., 8 figs., 1 tab

Measurement of AC electrical conductivity of single crystal Al2O3 during spallation-neutron irradiation

International Nuclear Information System (INIS)

Kennedy, J.C. III; Farnum, E.H.; Sommer, W.F.; Clinard, F.W. Jr.

1993-01-01

Samples of single crystal Al 2 O 3 , commonly known as sapphire, and polycrystalline Al 2 O 3 were irradiated with spallation neutrons at the Los Alamos Spallation Radiation Effects Facility (LASREF) under various temperature conditions and with a continuously applied alternating electric field. This paper describes the results of measurements on the sapphire samples. Neutron fluence and flux values are estimated values pending recovery and analysis of dosimetry packages. The conductivity increased approximately with the square root of the neutron flux at fluences less than 3 x 10 21 n/m 2 . The increase in conductivity reached saturated levels as high as 2 x 10 -2 (ohm-m) -1 at fluences as low as 2 x 10 22 n/m 2 . Frequency swept impedance measurements indicated a change in the electrical properties from capacitive to resistive behavior with increasing fluence

Neutron diffractometers for structural biology at spallation neutron sources

International Nuclear Information System (INIS)

Schoenborn, B.P.; Pitcher, E.

1994-01-01

Spallation neutron sources are ideal for diffraction studies of proteins and oriented molecular complexes. With spoliation neutrons and their time dependent wavelength structure, it is easy to electronically select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved snapshots. This optimized data quality with best peak-to-background ratios and provides adequate spatial and energy resolution to eliminate peak overlaps. The application of this concept will use choppers to select the desired Laue wavelength spectrum and employ focusing optics and large cylindrical 3 He detectors to optimize data collection rates. Such a diffractometer will cover a Laue wavelength range from 1 to 5 Angstrom with a flight path length of 10m and an energy resolution of 0.25 Angstrom. Moderator concepts for maximal flux distribution within this energy range will be discussed using calculated flux profiles. Since the energy resolution required for such timed data collection in this super Laue techniques is not very high, the use of a linac only (LAMPF) spoliation target is an exciting possibility with an order of magnitude increase in flux

Neutron diffractometers for structural biology at spallation neutron sources

Energy Technology Data Exchange (ETDEWEB)

Schoenborn, B.P.; Pitcher, E. [Los Alamos National Laboratory, NM (United States)

1994-12-31

Spallation neutron sources are ideal for diffraction studies of proteins and oriented molecular complexes. With spoliation neutrons and their time dependent wavelength structure, it is easy to electronically select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved snapshots. This optimized data quality with best peak-to-background ratios and provides adequate spatial and energy resolution to eliminate peak overlaps. The application of this concept will use choppers to select the desired Laue wavelength spectrum and employ focusing optics and large cylindrical {sup 3}He detectors to optimize data collection rates. Such a diffractometer will cover a Laue wavelength range from 1 to 5{Angstrom} with a flight path length of 10m and an energy resolution of 0.25{Angstrom}. Moderator concepts for maximal flux distribution within this energy range will be discussed using calculated flux profiles. Since the energy resolution required for such timed data collection in this super Laue techniques is not very high, the use of a linac only (LAMPF) spoliation target is an exciting possibility with an order of magnitude increase in flux.

Proton injection and RF capture in the national spallation neutron source

International Nuclear Information System (INIS)

Luccio, A.U.; Beebe-Wang, J.; Maletic, D.

1997-01-01

The accelerator system for the 1 to 5 MW National Spallation Neutron Source (NSNS) consists of a linac followed by a 1 GeV proton accumulator ring. Since the ring is a very high current machine, the injection and rf capture of the protons is deeply affected by transverse and longitudinal space charge effects. Results of numerical simulation of the process are presented together with considerations on methods and results of space charge treatment in high intensity proton storage rings

Engineering design of the EURISOL multi-MW spallation target

CERN Document Server

Herrera-Martínez, A; Ashrafi-Nik, M; Samec, K; Freibergs, J; Platacis, E

2007-01-01

The European Isotope Separation On-Line Radioactive Ion Beam project (EURISOL) is set to design the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW target assembly, all driven by a high-power particle accelerator. In this high power target station, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source. This article summarises the work carried out within Task 2 of the EURISOL Design Study, with special attention to the coupled neutronics of the mercury proton-to-neutron converter and the fission targets. The overall performance of the facility, which will sustain fast neutron fluxes of the order of 1...

ENGINEERING DESIGN OF THE EURISOL MULTI-MW SPALLATION TARGET

CERN Document Server

Adonai Herrera-Martinez*, Yacine Kadi, Morteza Ashrafi-Nik, Karel Samec, Janis Freibergs, Ernests Platacis

The European Isotope Separation On-Line Radioactive Ion Beam project (EURISOL) is set to design the ‘next-generation’ European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW target assembly, all driven by a high-power particle accelerator. In this high power target station, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source. This article summarises the work carried out within Task 2 of the EURISOL Design Study, with special attention to the coupled neutronics of the mercury proton-to-neutron converter and the fission targets. The overall performance of the facility, which will sustain fast neutron fluxes of the order ...

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.

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

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...

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

Monte Carlo modeling of neutron imaging at the SINQ spallation source

International Nuclear Information System (INIS)

Lebenhaft, J.R.; Lehmann, E.H.; Pitcher, E.J.; McKinney, G.W.

2003-01-01

Modeling of the Swiss Spallation Neutron Source (SINQ) has been used to demonstrate the neutron radiography capability of the newly released MPI-version of the MCNPX Monte Carlo code. A detailed MCNPX model was developed of SINQ and its associated neutron transmission radiography (NEUTRA) facility. Preliminary validation of the model was performed by comparing the calculated and measured neutron fluxes in the NEUTRA beam line, and a simulated radiography image was generated for a sample consisting of steel tubes containing different materials. This paper describes the SINQ facility, provides details of the MCNPX model, and presents preliminary results of the neutron imaging. (authors)

New science at the European Spallation Source

Energy Technology Data Exchange (ETDEWEB)

Finney, J L [University Coll., London (United Kingdom). Dept. of Physics and Astronomy

1996-05-01

The European Spallation Source is a trans-European project aimed at the ultimate construction of a next-generation pulsed spallation neutron source that will deliver 30 times the beam power of ISIS. The reference design for the proposed source has been set, and work is in progress to develop an updated scientific case for the construction of the source early in the next century. Together with improvements in instrumentation, effective flux gains of over two orders of magnitude are likely in some areas, opening up major new opportunities for the exploitation of neutron studies in fundamental, strategic, and applied science. (author)

Electron cloud instabilities in the Proton Storage Ring and Spallation Neutron Source

Directory of Open Access Journals (Sweden)

M. Blaskiewicz

2003-01-01

Full Text Available Electron cloud instabilities in the Los Alamos Proton Storage Ring and those foreseen for the Oak Ridge Spallation Neutron Source are examined theoretically, numerically, and experimentally.

Electron Cloud Mitigation in the Spallation Neutron Source Ring

International Nuclear Information System (INIS)

Wei, J.; Blaskiewicz, Michael; Brodowski, J.; Cameron, P.; Davino, Daniele; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Ludewig, H.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Catalan-Lasheras, N.; Macek, R.J.; Furman, Miguel A.; Aleksandrov, A.; Cousineau, S.; Danilov, V.; Henderson, S.

2008-01-01

The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H - injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron-cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation

Electron-cloud mitigation in the spallation neutron source ring

International Nuclear Information System (INIS)

Wei, J.; Blaskiewicz, M.; Brodowski, J.; Cameron, P.; Davino, D.; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Danilov, V.; Henderson, S.; Furman, M.; Pivi, M.; Macek, R.

2003-01-01

The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H- injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation

Thermal features of spallation window targets

International Nuclear Information System (INIS)

Martinez-Val, J. M.; Sordo, F.; Leon, P. T.

2007-01-01

Subcritical nuclear reactors have been proposed for a number of applications, from energy production to fertile-to-fissile conversion, and to transmutation of long-lived radio nuclei into stable or much shorter-lived nuclei. The main advantage of subcritical reactors is their large reactivity margin for not to attain prompt-supercritical power surges. On the contrary, subcritical reactors present some economic drawbacks and technical complexities that deserve suitable attention in the Research and Development phase. Namely, they need a very intense neutron source in order to keep the neutron flux and the reactor power at the required level. The most intense neutron source seems to be based on the proton-induced (or deuteron-induced) spallation reaction in heavy nuclei targets, which present very demanding thermal features that must be properly limited. Those limits pose upper bounds to the neutron yield of the target. In turn, the limits depend on the features of the impinging particle beam and the material composition and geometry of the target. Although the potential design window for spallation targets is rather wide, the analysis presented in this paper identifies specific topics that must properly be covered in the detailed project of a spallation source, in order to avoid unacceptable temperatures and mechanical stresses in the most critical parts of the source. In this paper, some calculations are reported on solid targets (water cooled or helium cooled) and molten metals targets. It is seen that thermal-hydraulic and mechanical calculations of spallation targets are fundamental elements in the coherent design of this type of very intense neutron sources. This coherence implies the need of a suitable trade-off among the relevant beam parameters (proton energy, total intensity and cross-section shape) and the features of the target (structural materials, coolant characteristics and target geometry). The goal of maximizing the neutron yield has to be checked

Spallation study with proton beams around 1 GeV: neutron production

International Nuclear Information System (INIS)

Boudard, A.; Borne, F.; Brochard, F.; Crespin, S.; Drake, D.; Duchazeaubeneix, J.C.; Durand, D.; Durand, J.M.; Frehaut, J.; Hanappe, F.; Kowalski, L.; Lebrun, C.; Lecolley, F.R.; Lecolley, J.F.; Ledoux, X.; Lefebvres, F.; Legrain, R.; Leray, S.; Louvel, M.; Martinez, E.; Meigo, S.I.; Menard, S.; Milleret, G.; Patin, Y.; Petibon, E.; Plouin, F.; Pras, P.; Schapira, J.P.; Stuttge, L.; Terrien, Y.; Thun, J.; Uematsu, M.; Varignon, C.; Volant, C.; Whittal, D.M.; Wlazlo, W.

2000-01-01

Experiments performed at Lab. Nat. SATURNE on neutron produced by spallation from proton beams in the range 0.8 - 1.6 GeV are presented. Experimental data compared with codes show a significant improvement of the recent intra-nuclear cascade (J. Cugnon). This is also true in the same way for the neutron production from thick targets. However the model underestimates the energetic neutrons produced in the backward direction and other quantities as residual nuclei cross sections are not accurately predicted

General-purpose readout electronics for white neutron source at China Spallation Neutron Source.

Science.gov (United States)

Wang, Q; Cao, P; Qi, X; Yu, T; Ji, X; Xie, L; An, Q

2018-01-01

The under-construction White Neutron Source (WNS) at China Spallation Neutron Source is a facility for accurate measurements of neutron-induced cross section. Seven spectrometers are planned at WNS. As the physical objectives of each spectrometer are different, the requirements for readout electronics are not the same. In order to simplify the development of the readout electronics, this paper presents a general method for detector signal readout. This method has advantages of expansibility and flexibility, which makes it adaptable to most detectors at WNS. In the WNS general-purpose readout electronics, signals from any kinds of detectors are conditioned by a dedicated signal conditioning module corresponding to this detector, and then digitized by a common waveform digitizer with high speed and high precision (1 GSPS at 12-bit) to obtain the full waveform data. The waveform digitizer uses a field programmable gate array chip to process the data stream and trigger information in real time. PXI Express platform is used to support the functionalities of data readout, clock distribution, and trigger information exchange between digitizers and trigger modules. Test results show that the performance of the WNS general-purpose readout electronics can meet the requirements of the WNS spectrometers.

Safety-technical lay-out of the operational environment of a high-power spallation target system of the megawatt class with mercury as target material

International Nuclear Information System (INIS)

Butzek, M.

2005-06-01

of the neutron guide system. Due to the high amount of safety relevant handling procedures, concepts for time efficient and safe handling of the major components have been developed. Based on the concepts shown in this thesis, construction and operation of a high power spallation source of the described kind seem to be feasible considering safety and costs. (orig.)

Magnets for the national spallation neutron source accumulator ring

International Nuclear Information System (INIS)

Tuozzolo, J.; Brodowski, J.; Danby, G.

1997-01-01

The National Spallation Neutron Source Accumulator Ring will require large aperture dipole magnets, strong focusing quadrupole magnets, and smaller low field dipole, quadrupole, and sextupole correcting magnets. All of the magnets will provide a fixed magnetic field throughout the accumulator's fill/storage/extraction cycle. Similar fixed field magnets will also be provided for the beam transport systems. Because of the high intensity in the accumulator, the magnets must be designed with high tolerances for optimum field quality and for the high radiation environment which may be present at the injection/extraction areas, near the collimators, and near the target area. Field specifications and field plots are presented as well as planned fabrication methods and procedures, cooling system design, support, and installation

A fission ionization detector for neutron flux measurements at a spallation source

Energy Technology Data Exchange (ETDEWEB)

Wender, S.A. (Los Alamos National Lab., Los Alamos, NM (United States)); Balestrini, S. (Los Alamos National Lab., Los Alamos, NM (United States)); Brown, A. (Los Alamos National Lab., Los Alamos, NM (United States)); Haight, R.C. (Los Alamos National Lab., Los Alamos, NM (United States)); Laymon, C.M. (Los Alamos National Lab., Los Alamos, NM (United States)); Lee, T.M. (Los Alamos National Lab., Los Alamos, NM (United States)); Lisowski, P.W. (Los Alamos National Lab., Los Alamos, NM (United States)); McCorkle, W. (Los Alamos National Lab., Los Alamos, NM (United States)); Nelson, R.O. (Los Alamos National Lab., Los Alamos, NM (United States)); Parker, W. (Los Alamos National Lab., Los Alamos, NM (United States)); Hill, N.W. (Oak Ridge National Lab., Oak Ridge, TN (United States))

1993-11-15

The construction of a neutron flux monitor that can measure absolute neutron intensities in the neutron energy range from below 1 MeV to over 500 MeV is described. The detector consists of an ionization chamber with several thin deposits of fissionable material. The ionization chamber is thin enough that it does not significantly affect the neutron beam and may be left in the neutron flight path during experimental measurements to continuously monitor the beam flux. The use of this monitor at the continuous-energy spallation neutron source at the WNR target area at LAMPF is described. (orig.)

A fission ionization detector for neutron flux measurements at a spallation source

International Nuclear Information System (INIS)

Wender, S.A.; Balestrini, S.; Brown, A.; Haight, R.C.; Laymon, C.M.; Lee, T.M.; Lisowski, P.W.; McCorkle, W.; Nelson, R.O.; Parker, W.; Hill, N.W.

1993-01-01

The construction of a neutron flux monitor that can measure absolute neutron intensities in the neutron energy range from below 1 MeV to over 500 MeV is described. The detector consists of an ionization chamber with several thin deposits of fissionable material. The ionization chamber is thin enough that it does not significantly affect the neutron beam and may be left in the neutron flight path during experimental measurements to continuously monitor the beam flux. The use of this monitor at the continuous-energy spallation neutron source at the WNR target area at LAMPF is described. (orig.)

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.

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.

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)

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.

CLEAR: Prospects for a low threshold neutrino experiment at the Spallation Neutron Source

International Nuclear Information System (INIS)

Scholberg, Kate

2008-01-01

A low-threshold neutrino scattering experiment at a high intensity stopped-pion neutrino source has the potential to measure coherent neutral current neutrino-nucleus elastic scattering. A promising prospect for the measurement of this process is a proposed noble-liquid-based experiment, dubbed CLEAR (Coherent Low Energy A (Nuclear) Recoils), at the Spallation Neutron Source. This poster will describe the CLEAR proposal and its physics reach.

Accelerator based continuous neutron source.

CERN Document Server

Shapiro, S M; Ruggiero, A G

2003-01-01

Until the last decade, most neutron experiments have been performed at steady-state, reactor-based sources. Recently, however, pulsed spallation sources have been shown to be very useful in a wide range of neutron studies. A major review of neutron sources in the US was conducted by a committee chaired by Nobel laureate Prof. W. Kohn: ''Neutron Sources for America's Future-BESAC Panel on Neutron Sources 1/93''. This distinguished panel concluded that steady state and pulsed sources are complementary and that the nation has need for both to maintain a balanced neutron research program. The report recommended that both a new reactor and a spallation source be built. This complementarity is recognized worldwide. The conclusion of this report is that a new continuous neutron source is needed for the second decade of the 20 year plan to replace aging US research reactors and close the US neutron gap. it is based on spallation production of neutrons using a high power continuous superconducting linac to generate pr...

Dynamically polarized samples for neutron protein crystallography at the Spallation Neutron Source

International Nuclear Information System (INIS)

Zhao, Jinkui; Pierce, Josh; Robertson, J. L.; Herwig, Kenneth W.; Myles, Dean; Cuneo, Matt; Li, Le; Meilleur, Flora; Standaert, Bob

2016-01-01

To prepare for the next generation neutron scattering instruments for the planned second target station at the Spallation Neutron Source (SNS) and to broaden the scientific impact of neutron protein crystallography at the Oak Ridge National Laboratory, we have recently ramped up our efforts to develop a dynamically polarized target for neutron protein crystallography at the SNS. Proteins contain a large amount of hydrogen which contributes to incoherent diffraction background and limits the sensitivity of neutron protein crystallography. This incoherent background can be suppressed by using polarized neutron diffraction, which in the same time also improves the coherent diffraction signal. Our plan is to develop a custom Dynamic Nuclear Polarization (DNP) setup tailored to neutron protein diffraction instruments. Protein crystals will be polarized at a magnetic field of 5 T and temperatures of below 1 K. After the dynamic polarization process, the sample will be brought to a frozen-spin mode in a 0.5 T holding field and at temperatures below 100 mK. In a parallel effort, we are also investigating various ways of incorporating polarization agents needed for DNP, such as site specific spin labels, into protein crystals. (paper)

CFD Study of the Active Part of the HYPER LBE Spallation Target System

International Nuclear Information System (INIS)

Cho, Chung-ho; Tak, Nam-il; Lee, Yong-bum; Choi, Jae-Hyuk

2007-01-01

In an accelerator driven system (ADS), a high-energy proton beam impinges on a heavy metal target to produce spallation neutrons that are multiplied in a subcritical blanket. Therefore, the spallation target is one of the most important units of an ADS. A beam power of 15-25 MW is required for an operation of the HYPER system. But, the design of a 20 MW spallation target is very challenging because more than 60% of a beam power is deposited as heat in a small volume of a target system. LBE is preferred as the target material due to its high neutron production rate, effective heat removal, low melting point and vapor pressure, low neutron absorption and good radiation damage properties. In addition, it can be used simultaneously as a reactor coolant. Single hemi-spherical beam window is considered for the HYPER target. The beam window is a thin physical barrier to separate the vacuum space from the LBE. It is exposed to high thermal and irradiation loads, which affect its life time. The integrity of the beam window is crucial for a safe operation of the HYPER, for preventing the penetration of the radioactive spallation products into the accelerator island. Therefore, a sufficient cooling capability of the beam window is one of the key issues of the target design. In the previous study, a series of parametric thermal and mechanical studies were made for the optimization of the HYPER target. The optimized target has a 0.2 cm thick beam window with a diameter of 35 cm. Also, a 30 cm wide proton beam with a uniform beam distribution should be adopted for the spallation target of the HYPER. A dual injection tube is adopted to economize the LBE flow in the primary system. This paper presents the numerical studies on the optimized spallation target system. Several advanced turbulence models with different grid structures are investigated by using a commercial computational fluid dynamics (CFD) code CFX 5.7.1

Lead-Bismuth-Eutectic Spallation Neutron Source for Nuclear Transmuter

International Nuclear Information System (INIS)

Gohar, Y.; Herceg, J.; Krajtl, L.; Micklich, B.; Pointer, D.; Saiveau, J.; Sofu, T.; Finck, P.

2002-01-01

A lead-bismuth eutectic (LBE) spallation target design concept has been developed for the subcritical multiplier (SCM) design of the accelerator-driven test facility (ADTF). The design is based on a coaxial geometrical configuration, which has been carefully analyzed and designed to achieve an optimum performance. The target design description, the results from the parametric studies, and the design analyses including neutronics, heat transfer, and hydraulics analyses are given in this paper. A detailed MCNPX geometrical model for the target has been developed to generate heating rates and nuclear responses in the structural material for the design process. The beam has a uniform distribution of 600 MeV protons and 5-MW total power. A small LBE buffer is optimized to reduce the irradiation damage in the SCM fuel elements from the scatter protons and the high-energy neutrons, to maximize the neutron yield to the SCM operation, and to provide inlet and outlet manifolds for the LBE coolant. A special attention has been given to the target window design to enhance its lifetime. The window volumetric heating is 766 W/cm 3 relative to 750 W/cm 3 in LBE for a 40-μA/cm 2 current density. The results show that the nuclear heating from the proton beam diminishes at about 32 cm along the beam axis in the LBE target material. The neutron contribution to the atomic displacement is in the range of 94 to ∼100% for the structure material outside the proton beam path. In the beam window, the neutron contribution is ∼74% and the proton beam is responsible for more than 95% of the total gas production. The proton contribution to the gas production vanishes outside the beam path. The LBE average velocity is ∼2 m/s. The heat transfer and the hydraulics analyses have been iterated to reduce the maximum temperature and the thermal stress level in the target window to enhance its operating life. (authors)

Feasibility study for the spallation neutron source (SNQ). Pt. 1

International Nuclear Information System (INIS)

Bauer, G.S.; Sebening, H.; Vetter, J.E.; Willax, H.

1981-06-01

A concept for a new neutron source for fundamental research has been developed and is described in this report. The spallation neutron source SNQ is characterized in its first stage by a time average thermal neutron flux of 7 x 10 14 cm -2 s -1 and a peak flux of 1.3 x 10 16 cm -2 s -1 at 100 Hz repetition rate. The scientific case is presented with particular emphasis on solid state and nuclear physics. In these research domains, unique conditions are given for experimental use. The proposed machine consists in its basic stage of a 1.1 GeV, 5 mA time average, 100 mA peak current proton linear accelerator, a rotating lead target, and H 2 O and D 2 O moderators. Additional beam channels are provided for experiments with protons at 350 MeV and at the final energy. Construction of the SNQ is considered feasible within eight years at a cost of 680 million DM. As future options, use of uranium as a target material, increase of the accelerator beam power by a factor of 2, addition of a pulse compressor and a second target station for pulsed neutron and neutrino research are described. As a back-up solution to the rotating target, a liquid metal target was studied. (orig.) [de

Universal odd-even staggering in isotopic fragmentation and spallation cross sections of neutron-rich fragments

Science.gov (United States)

Mei, B.; Tu, X. L.; Wang, M.

2018-04-01

An evident odd-even staggering (OES) in fragment cross sections has been experimentally observed in many fragmentation and spallation reactions. However, quantitative comparisons of this OES effect in different reaction systems are still scarce for neutron-rich nuclei near the neutron drip line. By employing a third-order difference formula, the magnitudes of this OES in extensive experimental cross sections are systematically investigated for many neutron-rich nuclei with (N -Z ) from 1 to 23 over a broad range of atomic numbers (Z ≈3 -50 ). A comparison of these magnitude values extracted from fragment cross sections measured in different fragmentation and spallation reactions with a large variety of projectile-target combinations over a wide energy range reveals that the OES magnitude is almost independent of the projectile-target combinations and the projectile energy. The weighted average of these OES magnitudes derived from cross sections accurately measured in different reaction systems is adopted as the evaluation value of the OES magnitude. These evaluated OES magnitudes are recommended to be used in fragmentation and spallation models to improve their predictions for fragment cross sections.

Design and implementation of low-Q diffractometers at spallation sources

International Nuclear Information System (INIS)

Seeger, P.A.; Hjelm, R.P.

1993-01-01

Low-Q diffractometers at spallation sources that use time of flight methods have been successfully implemented at several facilities, including the Los Alamos Neutron Scattering Center. The proposal to build new, more powerful, advanced spallation sources using advanced moderator concepts will provide luminosity greater than 20 times the brightest spallation source available today. These developments provide opportunity and challenge to expand the capabilities of present instruments with new designs. The authors review the use of time of flight for low-Q measurements and introduce new designs to extend the capabilities of present-day instruments. They introduce Monte Carlo methods to optimize design and simulate the performance of these instruments. The expected performance of the new instruments are compared to present day pulsed source- and reactor-based small-angle neutron scattering instruments. They review some of the new developments that will be needed to use the power of brighter sources effectively

Structural materials for fusion and spallation sources

International Nuclear Information System (INIS)

Cottrell, G.A.; Baker, L.J.

2003-01-01

Experimental investigation of neutron-induced irradiation damage in structural materials is fundamental to the development of magnetic confinement fusion. Proposals for the testing of candidate materials are described, indicating that a period of at least 10 years will elapse before a suitable high neutron fluence fusion test facility becomes available. In this circumstance, the possibility that neutron spallation sources could be exploited to shorten the time-scale of fusion materials development is attractive. Although fusion displacement and transmutation reaction rates can be replicated in spallation sources, there are significant differences arising from the harder neutron spectra and the presence of energetic protons. These differences, including higher energy PKA, electron heating effects, transmutation rates and pulsing are described and their consequences discussed, together with the concomitant development of theoretical models, needed to understand the effects. It is concluded that spallation source experiments could make a significant contribution to the database required for the validation of theoretical models, and hence reduce the time scale of fusion materials development

Study on induced radioactivity of China Spallation Neutron Source

International Nuclear Information System (INIS)

Wu Qingbiao; Wang Qingbin; Wu Jingmin; Ma Zhongjian

2011-01-01

China Spallation Neutron Source (CSNS) is the first High Energy Intense Proton Accelerator planned to be constructed in China during the State Eleventh Five-Year Plan period, whose induced radioactivity is very important for occupational disease hazard assessment and environmental impact assessment. Adopting the FLUKA code, the authors have constructed a cylinder-tunnel geometric model and a line-source sampling physical model, deduced proper formulas to calculate air activation, and analyzed various issues with regard to the activation of different tunnel parts. The results show that the environmental impact resulting from induced activation is negligible, whereas the residual radiation in the tunnels has a great influence on maintenance personnel, so strict measures should be adopted.(authors)

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

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

Science.gov (United States)

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

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

RF H-minus ion source development in China spallation neutron source

Science.gov (United States)

Chen, W.; Ouyang, H.; Xiao, Y.; Liu, S.; Lü, Y.; Cao, X.; Huang, T.; Xue, K.

2017-08-01

China Spallation Neutron Source (CSNS) phase-I project currently uses a Penning surface plasma H- ion source, which has a life time of several weeks with occasional sparks between high voltage electrodes. To extend the life time of the ion source and prepare for the CSNS phase-II, we are trying to develop a RF negative hydrogen ion source with external antenna. The configuration of the source is similar to the DESY external antenna ion source and SNS ion source. However several changes are made to improve the stability and the life time. Firstly, Si3N4 ceramic with high thermal shock resistance, and high thermal conductivity is used for plasma chamber, which can endure an average power of 2000W. Secondly, the water-cooled antenna is brazed on the chamber to improve the energy efficiency. Thirdly, cesium is injected directly to the plasma chamber if necessary, to simplify the design of the converter and the extraction. Area of stainless steel exposed to plasma is minimized to reduce the sputtering and degassing. Instead Mo, Ta, and Pt coated materials are used to face the plasma, which makes the self-cleaning of the source possible.

On the role of secondary pions in spallation targets

Energy Technology Data Exchange (ETDEWEB)

Mancusi, Davide [Paris-Saclay Univ., Gif-sur-Yvette (France). Den-Service d' Etude des Reacteurs et de Mathematiques Appliquees (SERMA); Lo Meo, Sergio [ENEA, Research Centre ' ' Ezio Clementel' ' , Bologna (Italy); INFN, Bologna (Italy); Colonna, Nicola [INFN, Bari (Italy); Boudard, Alain; David, Jean-Christophe; Leray, Sylvie [Paris-Saclay Univ., Gif-sur-Yvette (France). IRFU, CEA; Cortes-Giraldo, Miguel Antonio; Lerendegui-Marco, Jorge [Sevilla Univ. (Spain). Facultad de Fisica; Cugnon, Joseph [Liege Univ. (Belgium). AGO Dept.; Massimi, Cristian [INFN, Bologna (Italy); Bologna Univ. (Italy). Physics and Astronomy Dept.; Vlachoudis, Vasilis [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

2017-05-15

We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the nTOF lead spallation target, irradiated with 20 GeV/c protons, neutral pions are involved in the production of ∝ 90% of the high-energy photons; charged pions participate in ∝ 40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets. (orig.)

On the role of secondary pions in spallation targets

CERN Document Server

Mancusi, Davide; Colonna, Nicola; Boudard, Alain; Cortés-Giraldo, Miguel Antonio; Cugnon, Joseph; David, Jean-Christophe; Leray, Sylvie; Lerendegui-Marco, Jorge; Massimi, Cristian; Vlachoudis, Vasilis

2017-01-01

We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the n_TOF lead spallation target, irradiated with 20-GeV/c protons, neutral pions are involved in the production of ~90% of the high-energy photons; charged pions participate in ~40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets.

5 MW pulsed spallation neutron source, Preconceptual design study

Energy Technology Data Exchange (ETDEWEB)

1994-06-01

This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

5 MW pulsed spallation neutron source, Preconceptual design study

International Nuclear Information System (INIS)

1994-06-01

This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in ∼ 1 μsec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs

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.

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.

Results from the TARC experiment: spallation neutron phenomenology in lead and neutron-driven nuclear transmutation by adiabatic resonance crossing

Science.gov (United States)

Abánades, A.; Aleixandre, J.; Andriamonje, S.; Angelopoulos, A.; Apostolakis, A.; Arnould, H.; Belle, E.; Bompas, C. A.; Brozzi, D.; Bueno, J.; Buono, S.; Carminati, F.; Casagrande, F.; Cennini, P.; Collar, J. I.; Cerro, E.; Del Moral, R.; Díez, S.; Dumps, L.; Eleftheriadis, C.; Embid, M.; Fernández, R.; Gálvez, J.; García, J.; Gelès, C.; Giorni, A.; González, E.; González, O.; Goulas, I.; Heuer, D.; Hussonnois, M.; Kadi, Y.; Karaiskos, P.; Kitis, G.; Klapisch, R.; Kokkas, P.; Lacoste, V.; Le Naour, C.; López, C.; Loiseaux, J. M.; Martínez-Val, J. M.; Méplan, O.; Nifenecker, H.; Oropesa, J.; Papadopoulos, I.; Pavlopoulos, P.; Pérez-Enciso, E.; Pérez-Navarro, A.; Perlado, M.; Placci, A.; Poza, M.; Revol, J.-P.; Rubbia, C.; Rubio, J. A.; Sakelliou, L.; Saldaña, F.; Savvidis, E.; Schussler, F.; Sirvent, C.; Tamarit, J.; Trubert, D.; Tzima, A.; Viano, J. B.; Vieira, S.; Vlachoudis, V.; Zioutas, K.

2002-02-01

We summarize here the results of the TARC experiment whose main purpose is to demonstrate the possibility of using Adiabatic Resonance Crossing (ARC) to destroy efficiently Long-Lived Fission Fragments (LLFFs) in accelerator-driven systems and to validate a new simulation developed in the framework of the Energy Amplifier programme. An experimental set-up was installed in a CERN PS proton beam line to study how neutrons produced by spallation at relatively high energy ( E n⩾1 MeV) slow down quasi-adiabatically with almost flat isolethargic energy distribution and reach the capture resonance energy of an element to be transmuted where they will have a high probability of being captured. Precision measurements of energy and space distributions of spallation neutrons (using 2.5 and 3.5 GeV/ c protons) slowing down in a 3.3 m×3.3 m×3 m lead volume and of neutron capture rates on LLFFs 99Tc, 129I, and several other elements were performed. An appropriate formalism and appropriate computational tools necessary for the analysis and understanding of the data were developed and validated in detail. Our direct experimental observation of ARC demonstrates the possibility to destroy, in a parasitic mode, outside the Energy Amplifier core, large amounts of 99Tc or 129I at a rate exceeding the production rate, thereby making it practical to reduce correspondingly the existing stockpile of LLFFs. In addition, TARC opens up new possibilities for radioactive isotope production as an alternative to nuclear reactors, in particular for medical applications, as well as new possibilities for neutron research and industrial applications.

The spallation neutron source SINQ. A new large facility for research at PSI

International Nuclear Information System (INIS)

Bauer, G.S.; Crawford, J.F.

1994-01-01

This document is intended to familiarize the non-specialist with the principles of neutron scattering and some of its applications. It presents an overview of the foundations of neutron scattering, the basic types of instruments used, and their principles of operation. The design concept and some technical details of the spallation neutron source are described for the benefit of the scientifically or technically interested reader. In future this source will form the heart of the instruments available to PSI's wide community of neutron scattering researchers. (author) 32 figs., 1 tab

The performance of neutron scattering spectrometers at a long-pulse spallation source

International Nuclear Information System (INIS)

Pynn, R.

1997-01-01

In this document the author considers the performance of a long pulse spallation source for those neutron scattering experiments that are usually performed with a monochromatic beam at a continuous wave (CW) source such as a nuclear reactor. The first conclusion drawn is that comparison of the performance of neutron scattering spectrometers at CW and pulsed sources is simpler for long-pulsed sources than it is for the short-pulse variety. Even though detailed instrument design and assessment will require Monte Carlo simulations (which have already been performed at Los Alamos for SANS and reflectometry), simple arguments are sufficient to assess the approximate performance of spectrometers at an LPSS and to support the contention that a 1 MW long-pulse source can provide attractive performance, especially for instrumentation designed for soft-condensed-matter science. Because coupled moderators can be exploited at such a source, its time average cold flux is equivalent to that of a research reactor with a power of about 15 MW, so only a factor of 4 gain from source pulsing is necessary to obtain performance that is comparable with the ILL. In favorable cases, the gain from pulsing can be even more than this, approaching the limit set by the peak flux, giving about 4 times the performance of the ILL. Because of its low duty factor, an LPSS provides the greatest performance gains for relatively low resolution experiments with cold neutrons. It should thus be considered complementary to short pulse sources which are most effective for high resolution experiments using thermal or epithermal neutrons

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

Energy Technology Data Exchange (ETDEWEB)

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

1999-03-29

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

Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring

International Nuclear Information System (INIS)

Wei, J.

1999-01-01

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

A proposal for a long-pulse spallation source at Los Alamos National Laboratory

International Nuclear Information System (INIS)

Pynn, R.; Weinacht, D.

1995-01-01

Los Alamos National Laboratory is proposing a new spallation neutron source that will provide the US with an internationally competitive facility for neutron science and technology that can be built in approximately three years for less than $100 million. The establishment of a 1-MW, long-pulse spallation source (LPSS) at the Los Alamos Neutron Science Center (LANSCE) will meet many of the present needs of scientists in the neutron scattering community and provide a significant boost to neutron research in the US. The new facility will support the development of a future, more intense spallation neutron source, that is planned by DOE's Office of Energy Research. Together with the existing short pulse spallation source (SPSS) at the Manual Lujan, Jr. Neutron Scattering Center (MLNSC) at Los Alamos, the new LPSS will provide US scientists with a complementary pair of high-performance neutron sources to rival the world's leading facilities in Europe

A proposal for a long-pulse spallation source at Los Alamos National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Pynn, R; Weinacht, D [Los Alamos National Lab., NM (United States)

1995-11-01

Los Alamos National Laboratory is proposing a new spallation neutron source that will provide the U.S. with an internationally competitive facility for neutron science and technology that can be built in approximately three years for less than $100 million. The establishment of a 1-MW long-pulse spallation source (LPSS) at the Los Alamos Neutron Science Center (LANSCE) will meet many of the present needs of scientists in the neutron scattering community and provide a significant boost to neutron research in the U.S. The new facility will support the development of a future, more intense spallation neutron source, that is planned by DOE`s Office of Energy Research. Together with the existing short pulse spallation source (SPSS) at the Manual Lujan, Jr. Neutron Scattering Center (MLNSC) at Los Alamos, the new LPSS will provide U.S. scientists with a complementary pair of high-performance neutron sources to rival the world`s leading facilities in Europe. (author) 1 ref.

A proposal for a long-pulse spallation source at Los Alamos National Laboratory

International Nuclear Information System (INIS)

Pynn, R.; Weinacht, D.

1995-01-01

Los Alamos National Laboratory is proposing a new spallation neutron source that will provide the U.S. with an internationally competitive facility for neutron science and technology that can be built in approximately three years for less than $100 million. The establishment of a 1-MW long-pulse spallation source (LPSS) at the Los Alamos Neutron Science Center (LANSCE) will meet many of the present needs of scientists in the neutron scattering community and provide a significant boost to neutron research in the U.S. The new facility will support the development of a future, more intense spallation neutron source, that is planned by DOE's Office of Energy Research. Together with the existing short pulse spallation source (SPSS) at the Manual Lujan, Jr. Neutron Scattering Center (MLNSC) at Los Alamos, the new LPSS will provide U.S. scientists with a complementary pair of high-performance neutron sources to rival the world's leading facilities in Europe. (author) 1 ref

Basic design of shield blocks for a spallation neutron source under the high-intensity proton accelerator project

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Katsuhiko; Maekawa, Fujio; Takada, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

Under the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC), a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed as a main part of the Materials and Life Science Facility. Overall dimensions of a biological shield of the neutron source had been determined by evaluation of shielding performance by Monte Carlo calculations. This report describes results of design studies on an optimum dividing scheme in terms of cost and treatment and mechanical strength of shield blocks for the biological shield. As for mechanical strength, it was studied whether the shield blocks would be stable, fall down or move to a horizontal direction in case of an earthquake of seismic intensity of 5.5 (250 Gal) as an abnormal load. For ceiling shielding blocks being supported by both ends of the long blocks, maximum bending moment and an amount of maximum deflection of their center were evaluated. (author)

Basic design of shield blocks for a spallation neutron source under the high-intensity proton accelerator project

CERN Document Server

Yoshida, K; Takada, H

2003-01-01

Under the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC), a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed as a main part of the Materials and Life Science Facility. Overall dimensions of a biological shield of the neutron source had been determined by evaluation of shielding performance by Monte Carlo calculations. This report describes results of design studies on an optimum dividing scheme in terms of cost and treatment and mechanical strength of shield blocks for the biological shield. As for mechanical strength, it was studied whether the shield blocks would be stable, fall down or move to a horizontal direction in case of an earthquake of seismic intensity of 5.5 (250 Gal) as an abnormal load. For ceiling shielding blocks being supported by both ends of the long blocks, maximum bending moment and an amount of maximum deflection of their center were evaluated.

Opportunities for Neutrino Physics at the Spallation Neutron Source: A White Paper

Energy Technology Data Exchange (ETDEWEB)

Bolozdynya, A. [Moscow Phys. Eng. Inst.; Cavanna, F. [INFN, Aquila; Efremenko, Y. [Tennessee U.; Garvey, G. T. [Los Alamos; Gudkov, V. [South Carolina U.; Hatzikoutelis, A. [Tennessee U.; Hix, W. R. [Oak Ridge; Louis, W. C. [Los Alamos; Link, J. M. [Virginia Tech.; Markoff, D. M. [North Carolina Central U.; Mills, G. B. [Los Alamos; Patton, K. [North Carolina State U.; Ray, H. [Florida U.; Scholberg, K. [Duke U.; Van de Water, R. G. [Los Alamos; Virtue, C. [Laurentian U.; White, D. H. [Los Alamos; Yen, S. [TRIUMF; Yoo, J. [Fermilab

2012-11-01

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this document, the product of a workshop at the SNS in May 2012, we describe this free, high-quality stopped-pion neutrino source and outline various physics that could be done using it. We describe without prioritization some specific experimental configurations that could address these physics topics.

Neutron Science Project at JAERI

International Nuclear Information System (INIS)

Oyama, Yukio

1998-01-01

Japan Atomic Energy Research Institute, JAERI, is proposing the Neutron Science Project which aims at bringing about scientific and technological innovation in the fields of basic science and nuclear technology for the 21st century, using high intense spallation neutron source. The research areas to be promoted by the project are neutron structural biology, material science, nuclear physics and various technology developments for accelerator-driven transmutation of long-lived radionuclides which are associated with nuclear power generation. JAERI has been carrying out a R and D program for the partitioning and transmutation with the intention to solve the problem of nuclear fuel cycle backend. The accelerator-driven transmutation study is also covered with this program. In the present stage of the project, a conceptual design is being prepared for a research complex utilizing spallation neutrons, including a high intensity pulsed and steady spallation neutron source with 1.5 GeV and 8 MW superconducting proton linac. The idea and facility plan of the project is described, including the status of technological development of the accelerator, target and facilities. (author)

Neutron Science Project at JAERI

Energy Technology Data Exchange (ETDEWEB)

Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-03-01

Japan Atomic Energy Research Institute, JAERI, is proposing the Neutron Science Project which aims at bringing about scientific and technological innovation in the fields of basic science and nuclear technology for the 21st century, using high intense spallation neutron source. The research areas to be promoted by the project are neutron structural biology, material science, nuclear physics and various technology developments for accelerator-driven transmutation of long-lived radionuclides which are associated with nuclear power generation. JAERI has been carrying out a R and D program for the partitioning and transmutation with the intention to solve the problem of nuclear fuel cycle backend. The accelerator-driven transmutation study is also covered with this program. In the present stage of the project, a conceptual design is being prepared for a research complex utilizing spallation neutrons, including a high intensity pulsed and steady spallation neutron source with 1.5 GeV and 8 MW superconducting proton linac. The idea and facility plan of the project is described, including the status of technological development of the accelerator, target and facilities. (author)

Spallation Neutron Source Drift Tube Linac Resonance Control Cooling System Modeling

CERN Document Server

Tang, Johnny Y; Champion, Marianne M; Feschenko, Alexander; Gibson, Paul; Kiselev, Yuri; Kovalishin, A S; Kravchuk, Leonid V; Kvasha, Adolf; Schubert, James P

2005-01-01

The Resonance Control Cooling System (RCCS) for the warm linac of the Spallation Neutron Source was designed by Los Alamos National Laboratory. The primary design focus was on water cooling of individual component contributions. The sizing the RCCS water skid was accomplished by means of a specially created SINDA/FLUINT model tailored to these system requirements. A new model was developed in Matlab Simulink and incorporates actual operational values and control valve interactions. Included is the dependence of RF input power on system operation, cavity detuning values during transients, time delays that result from water flows through the heat exchanger, the dynamic process of water warm-up in the cooling system due to dissipated RF power on the cavity surface, differing contributions on the cavity detuning due to drift tube and wall heating, and a dynamic model of the heat exchanger with characteristics in close agreement to the real unit. Because of the Matlab Simulink model, investigation of a wide range ...

A neutron booster for spallation sources--application to accelerator driven systems and isotope production

CERN Document Server

Galy, J; Van Dam, H; Valko, J

2002-01-01

One can design a critical system with fissile material in the form of a thin layer on the inner surface of a cylindrical neutron moderator such as graphite or beryllium. Recently, we have investigated the properties of critical and near critical systems based on the use of thin actinide layers of uranium, plutonium and americium. The thickness of the required fissile layer depends on the type of fissile material, its concentration in the layer and on the geometrical arrangement, but is typically in the mu m-mm range. The resulting total mass of fissile material can be as low as 100 g. Thin fissile layers have a variety of applications in nuclear technology--for example in the design neutron amplifiers for medical applications and 'fast' islands in thermal reactors for waste incineration. In the present paper, we investigate the properties of a neutron booster unit for spallation sources and isotope production. In those applications a layer of fissile material surrounds the spallation source. Such a module cou...

3-dimensional shielding design for a spallation neutron source facility in the high-intensity proton accelerator project

Energy Technology Data Exchange (ETDEWEB)

Tamura, Masaya; Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2003-03-01

Evaluation of shielding performance for a 1 MW spallation neutron source facility in the Materials and Life Science Facility being constructed in the High-Intensity Proton Accelerator Project (J-PARC) is important from a viewpoint of radiation safety and optimization of arrangement of components. This report describes evaluated results for the shielding performance with modeling three-dimensionally whole structural components including gaps between them in detail. A Monte Carlo calculation method with MCNPX2.2.6 code and LA-150 library was adopted. Streaming and void effects, optimization of shield for cost reduction and optimization of arrangement of structures such as shutters were investigated. The streaming effects were investigated quantitatively by changing the detailed structure of components and gap widths built into the calculation model. Horizontal required shield thicknesses were ranged from about 6.5 m to 7.5 m as a function of neutron beam line angles. A shutter mechanism for a horizontal neutron reflectometer that was directed downward was devised, and it was shown that the shielding performance of the shutter was acceptable. An optimal biological shield configuration was finally determined according to the calculated results. (author)

Design progress of cryogenic hydrogen system for China Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Wang, G. P.; Zhang, Y.; Xiao, J.; He, C. C.; Ding, M. Y.; Wang, Y. Q.; Li, N.; He, K. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P.R. (China)

2014-01-29

China Spallation Neutron Source (CSNS) is a large proton accelerator research facility with 100 kW beam power. Construction started in October 2011 and is expected to last 6.5 years. The cryogenic hydrogen circulation is cooled by a helium refrigerator with cooling capacity of 2200 W at 20 K and provides supercritical hydrogen to neutron moderating system. Important progresses of CSNS cryogenic system were concluded as follows. Firstly, process design of cryogenic system has been completed including helium refrigerator, hydrogen loop, gas distribution, and safety interlock. Secondly, an accumulator prototype was designed to mitigate pressure fluctuation caused by dynamic heat load from neutron moderation. Performance test of the accumulator has been carried out at room and liquid nitrogen temperature. Results show the accumulator with welding bellows regulates hydrogen pressure well. Parameters of key equipment have been identified. The contract for the helium refrigerator has been signed. Mechanical design of the hydrogen cold box has been completed, and the hydrogen pump, ortho-para hydrogen convertor, helium-hydrogen heat exchanger, hydrogen heater, and cryogenic valves are in procurement. Finally, Hydrogen safety interlock has been finished as well, including the logic of gas distribution, vacuum, hydrogen leakage and ventilation. Generally, design and construction of CSNS cryogenic system is conducted as expected.

Mechanical Engineering of the Linac for the Spallation Neutron Source

International Nuclear Information System (INIS)

Bultman, N.K.; Chen, Z.; Collier, M.; Erickson, J.L.; Guthrie, A.; Hunter, W.T.; Ilg, T.; Meyer, R.K.; Snodgrass, N.L.

1999-01-01

The linac for the Spallation Neutron Source (SNS) Project will accelerate an average current of 1 mA of H - ions from 20 MeV to 1GeV for injection into an accumulator ring. The linac will be an intense source of H - ions and as such requires advanced design techniques to meet project technical goals as well as to minimize costs. The DTL, CCDTL and CCL are 466m long and operate at 805 MHz with a maximum H - input current of 28 mA and 7% rf duty factor. The Drift Tube Linac is a copper-plated steel structure using permanent magnetic quadrupoles. The Coupled-Cavity portions are brazed copper structures and use electromagnetic quads. RF losses in the copper are 80 MW, with total rf power supplied by 52 klystrons. Additionally, the linac is to be upgraded to the 2- and 4-MW beam power levels with no increase in duty factor. The authors give an overview of the linac mechanical engineering effort and discuss the special challenges and status of the effort

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

Science.gov (United States)

Bowman, Charles D.

1992-01-01

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

Science.gov (United States)

Bowman, C.D.

1992-11-03

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

Status of helium-production reaction studies with a spallation neutron source

International Nuclear Information System (INIS)

Haight, R.C.; Bateman, F.B.; Chadwick, M.B.

1994-01-01

Alpha--particle production cross sections and spectra are being measured at the spallation source of fast neutrons at the Los Alamos Meson Physics Facility (LAMPF). Detectors at angles of 30, 60, 90 and 135 degree are used to identify alpha particles, measure their energy spectra, and indicate the time-of-flight, and hence the energy, of the neutrons inducing the reaction. The useful neutron energy ranges from less than 1 MeV to approximately 50 MeV for the present experimental setup. Targets under study at present include C, N, O, 27 Al, Si, 51 V, 56 Fe, 59 Co, 58,60 Ni, 89 Y and 93 Nb. Results for 59 Co illustrate the capabilities of the approach

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.

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)

Characterization of γ-ray background at IMAT beamline of ISIS Spallation Neutron Source

Science.gov (United States)

Festa, G.; Andreani, C.; Arcidiacono, L.; Burca, G.; Kockelmann, W.; Minniti, T.; Senesi, R.

2017-08-01

The environmental γ -ray background on the IMAT beamline at ISIS Spallation Neutron Source, Target Station 2, is characterized via γ spectroscopy. The measurements include gamma exposure at the imaging detector position, along with the gamma background inside the beamline. Present results are discussed and compared with previous measurements recorded at INES and VESUVIO beamlines operating at Target Station 1. They provide new outcome for expanding and optimizing the PGAA experimental capability at the ISIS neutron source for the investigation of materials, engineering components and cultural heritage objects at the ISIS neutron source.

Characterization of γ-ray background at IMAT beamline of ISIS Spallation Neutron Source

International Nuclear Information System (INIS)

Festa, G.; Andreani, C.; Arcidiacono, L.; Senesi, R.; Burca, G.; Kockelmann, W.; Minniti, T.

2017-01-01

The environmental γ -ray background on the IMAT beamline at ISIS Spallation Neutron Source, Target Station 2, is characterized via γ  spectroscopy. The measurements include gamma exposure at the imaging detector position, along with the gamma background inside the beamline. Present results are discussed and compared with previous measurements recorded at INES and VESUVIO beamlines operating at Target Station 1. They provide new outcome for expanding and optimizing the PGAA experimental capability at the ISIS neutron source for the investigation of materials, engineering components and cultural heritage objects at the ISIS neutron source.

Analysis of the monitoring system for the spallation neutron source 'SINQ'

International Nuclear Information System (INIS)

Badreddin, E.

1998-01-01

Petri Net models (PN) and Fault-Tree Analysis (FTA) are employed for the purpose of reliability analysis of the spallation neutron source SINQ. The monitoring and shut-down system (SDS) structure is investigated using a Petri-Net model. The reliability data are processed using a Fault-Tree model of the dominant part. Finally, suggestions for the improvement of system availability are made. (author)

The RADEX facility as a tool for studies of radiation damage under proton and spallation neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Koptelov, E.A.; Lebedev, S.G.; Matveev, V.A.; Sobolevsky, N.M. [Institute for Nuclear Research of Russian Academy of Sciences, Moscow (Russian Federation); Strebkov, Yu.S.; Subbotin, A.V. [Research and Development Institute of Power Engineering, Moscow (Russian Federation)

2001-03-01

We present results of numerical modeling for processes of primary protons and spallation neutrons interactions with structural materials at the RADiation EXperiment facility of the Neutron Complex. The installation has a vertical irradiation channel inside the beam stop for horizontally incident protons with energies up to 600 MeV of the Moscow Meson Factory of the INR (Institute for Nuclear Research) RAS (Russian Academy of Science). The calculations are based on a set of computer codes SHIELD and RADDAM, which were developed in the INR RAS and give data on point defect generation by irradiation, rate of accumulation of H and He atoms produced in nuclear reactions, energetic spectra of primary knocked-off atoms in collision displacements, temperature of samples under irradiation. Different positions of the channel, which are available by rotation of a target relatively the vertical axis for angles 0, 60, 120 and 180 degrees to the proton beam direction, are considered. Changes of irradiation damage parameters due to various inputs of primary protons and spallation neutrons at different target orientations are demonstrated. It is shown also that the spallation neutron facility RADEX may provide with perspective experimental possibilities for modeling of irradiation conditions for fusion reactors ITER and DEMO. (author)

The general concept for a spallation neutron source in the Federal Republic of Germany

International Nuclear Information System (INIS)

Bauer, G.S.

1982-01-01

In a collaborative effort between the two German nuclear research centres at Karlsruhe and at Juelich, a reference concept for a spallation neutron source has been studied which would be suitable to satisfy the medium term needs in neutrons for fundamental research and to serve a large number of other scientific disciplines as well. The reference facility, consisting of a high power proton linac for 5 mA time average current of 1.1 GeV protons and a rotating lead target with hybrid H 2 O-D 2 O moderators can deliver a thermal neutron flux equivalent to 7 x 10 14 cm -2 s -1 at the beam tube noses. Pulsed operation of the accelerator results in an intensity modulation of this flux at a repitition rate of 100 Hz with a peak flux of 1.3 x 10 16 cm -2 s -1 and a pulse width of 510 μs. Further possible improvements were considered, consisting in the use of uranium as target material and in the addition of a proton pulse compressor to increase the neutron peak flux especially in the epithermal energy range and to provide a time structure suitable for neutrino and muon research. To realize this concept in a fashion compatible with existing constraints while still serving a maximum number of users at the earliest possible date, a staged concept is being considered by KFA Juelich. (orig.) [de

BNL feasibility studies of spallation neutron sources

International Nuclear Information System (INIS)

Lee, Y.Y.; Ruggiero, A.G.; Van Steenbergen, A.; Weng, W.T.

1995-01-01

This paper is the summary of conceptual design studies of a 5 MW Pulsed Spallation Neutron Source (PSNS) conducted by an interdepartmental study group at Brookhaven National Laboratory. The study was made of two periods. First, a scenario based on the use of a 600 MeV Linac followed by two fast-cycling 3.6 GeV Synchrotrons was investigated. Then, in a subsequent period, the attention of the study was directed toward an Accumulator scenario with two options: (1) a 1.25 GeV normal conducting Linac followed by two Accumulator Rings, and (2) a 2.4 GeV superconducting Linac followed by a single Accumulator Ring. The study did not make any reference to a specific site

Fast neutron irradiation tests of flash memories used in space environment at the ISIS spallation neutron source

Directory of Open Access Journals (Sweden)

C. Andreani

2018-02-01

Full Text Available This paper presents a neutron accelerated study of soft errors in advanced electronic devices used in space missions, i.e. Flash memories performed at the ChipIr and VESUVIO beam lines at the ISIS spallation neutron source. The two neutron beam lines are set up to mimic the space environment spectra and allow neutron irradiation tests on Flash memories in the neutron energy range above 10 MeV and up to 800 MeV. The ISIS neutron energy spectrum is similar to the one occurring in the atmospheric as well as in space and planetary environments, with intensity enhancements varying in the range 108- 10 9 and 106- 10 7 respectively. Such conditions are suitable for the characterization of the atmospheric, space and planetary neutron radiation environments, and are directly applicable for accelerated tests of electronic components as demonstrated here in benchmark measurements performed on flash memories.

Fast neutron irradiation tests of flash memories used in space environment at the ISIS spallation neutron source

Science.gov (United States)

Andreani, C.; Senesi, R.; Paccagnella, A.; Bagatin, M.; Gerardin, S.; Cazzaniga, C.; Frost, C. D.; Picozza, P.; Gorini, G.; Mancini, R.; Sarno, M.

2018-02-01

This paper presents a neutron accelerated study of soft errors in advanced electronic devices used in space missions, i.e. Flash memories performed at the ChipIr and VESUVIO beam lines at the ISIS spallation neutron source. The two neutron beam lines are set up to mimic the space environment spectra and allow neutron irradiation tests on Flash memories in the neutron energy range above 10 MeV and up to 800 MeV. The ISIS neutron energy spectrum is similar to the one occurring in the atmospheric as well as in space and planetary environments, with intensity enhancements varying in the range 108- 10 9 and 106- 10 7 respectively. Such conditions are suitable for the characterization of the atmospheric, space and planetary neutron radiation environments, and are directly applicable for accelerated tests of electronic components as demonstrated here in benchmark measurements performed on flash memories.

ELECTRON CLOUD AT COLLIMATOR AND INJECTION REGION OF THE SPALLATION NEUTRON SOURCE ACCUMULATOR RING

International Nuclear Information System (INIS)

WANG, L.; HSEUH, H.-C.; LEE, Y.Y.; RAPARIA, D.; WEI, J.; COUSINEAU, S.

2005-01-01

The beam loss along the Spallation Neutron Source's accumulator ring is mainly located at the collimator region and injection region. This paper studied the electron cloud build-up at these two regions with the three-dimension program CLOUDLAND

γ-Ray background sources in the VESUVIO spectrometer at ISIS spallation neutron source

International Nuclear Information System (INIS)

Pietropaolo, A.; Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Schooneveld, E.M.; Andreani, C.; Senesi, R.

2009-01-01

An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted, trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump.

γ-Ray background sources in the VESUVIO spectrometer at ISIS spallation neutron source

Science.gov (United States)

Pietropaolo, A.; Perelli Cippo, E.; Gorini, G.; Tardocchi, M.; Schooneveld, E. M.; Andreani, C.; Senesi, R.

2009-09-01

An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted, trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump.

{gamma}-Ray background sources in the VESUVIO spectrometer at ISIS spallation neutron source

Energy Technology Data Exchange (ETDEWEB)

Pietropaolo, A. [CNISM Milano-Bicocca, Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: antonino.pietropaolo@mib.infn.it; Perelli Cippo, E. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); Gorini, G. [CNISM Milano-Bicocca, Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), Universita degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma (Italy); Tardocchi, M. [Universita degli Studi di Milano-Bicocca, Dipartimento di Fisica ' G. Occhialini' , Piazza della Scienza 3, 20126 Milano (Italy); Schooneveld, E.M. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire 0QX OX11 (United Kingdom); Andreani, C.; Senesi, R. [Universia degli Studi di Roma Tor Vergata, Dipartimento di Fisica and NAST Center (Nanoscienze-Nanotecnologie-Strumentazione), via della Ricerca Scientifica 1, 00133 Roma (Italy)

2009-09-01

An investigation of the gamma background was carried out in the VESUVIO spectrometer at the ISIS spallation neutron source. This study, performed with a yttrium-aluminum-perovskite (YAP) scintillator, follows high resolution pulse height measurements of the gamma background carried out on the same instrument with the use of a high-purity germanium detector. In this experimental work, a mapping of the gamma background was attempted, trying to find the spatial distribution and degree of directionality of the different contributions identified in the previous study. It is found that the gamma background at low times is highly directional and mostly due to the gamma rays generated in the moderator-decoupler system. The other contributions, consistently to the findings of a previous experiment, are identified as a nearly isotropic one due to neutron absorption in the walls of the experimental hall, and a directional one coming from the beam dump.

Shielding design study for the JAERI/KEK spallation neutron source

International Nuclear Information System (INIS)

Maekawa, Fujio; Teshigawara, Makoto; Konno, Chikara; Ikeda, Yujiro; Watanabe, Noboru

2001-01-01

Shielding design for the JAERI/KEK spallation neutron source was studied. Bulk shielding characteristics and optimization of a beam shutter were investigated by using Monte Carlo calculation code NMTC/JAM and MCNP with LA-150 neutron cross-section library. The following remarks were derived. (1) Neutron dose outside of the concrete shield at 6.6 m from the center is ∼10 μSv/hr regardless of angles with respect to the proton beam axis. The neutron dose can be reduced more than a factor of 30 by adding natural boron of 5 wt% in the concrete. (2) When a beam shutter position just outside the void vessel and the shutter length of 2 m are assumed, a shutter made of copper (1.7 m) with polyethylene (0.3 m) is the optimum in terms of shielding performance as well as cost merit. A shutter made of tungsten is not so effective. (3) Further studies are needed for optimization of beam shutter position. (author)

The concept of a European spallation neutron source (ESS)

Energy Technology Data Exchange (ETDEWEB)

Bauer, G.S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-11-01

The next generation neutron source in Europe, which was studied by a collaboration between twelve laboratories, has been conceived as a 5 MW short pulse spallation source because of the superior overall scientific potential attributed to such a facility relative to all other options considered. While the accelerator side can use essentially established technology with some extensions in performance, a novel target concept based on the use of Mercury as a flowing liquid metal target was developed, which is not only expected to lead the way further into the future, but which was also found to give the best neutronic performance of all known choices. Close permanent interaction with a large user community yielded important input for the concept in general and for the upcoming R and D and design phases in particular. (author)

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

Plans for a Collaboratively Developed Distributed Control System for the Spallation Neutron Source

International Nuclear Information System (INIS)

DeVan, W.R.; Gurd, D.P.; Hammonds, J.; Lewis, S.A.; Smith, J.D.

1999-01-01

The Spallation Neutron Source (SNS) is an accelerator-based pulsed neutron source to be built in Oak Ridge, Tennessee. The facility has five major sections - a ''front end'' consisting of a 65 keV H - ion source followed by a 2.5 MeV RFQ; a 1 GeV linac; a storage ring; a 1MW spallation neutron target (upgradeable to 2 MW); the conventional facilities to support these machines and a suite of neutron scattering instruments to exploit them. These components will be designed and implemented by five collaborating institutions: Lawrence Berkeley National Laboratory (Front End), Los Alamos National Laboratory (Linac); Brookhaven National Laboratory (Storage Ring); Argonne National Laboratory (Instruments); and Oak Ridge National Laboratory (Neutron Source and Conventional Facilities). It is proposed to implement a fully integrated control system for all aspects of this complex. The system will be developed collaboratively, with some degree of local autonomy for distributed systems, but centralized accountability. Technical integration will be based upon the widely-used EPICS control system toolkit, and a complete set of hardware and software standards. The scope of the integrated control system includes site-wide timing and synchronization, networking and machine protection. This paper discusses the technical and organizational issues of planning a large control system to be developed collaboratively at five different institutions, the approaches being taken to address those issues, as well as some of the particular technical challenges for the SNS control system

Tool for the study of matter - the spallation neutron source. Werkzeug zur Erforschung der Materie - die Spallations-Neutronenquelle

Energy Technology Data Exchange (ETDEWEB)

1983-01-01

It deals with the optimal use of a whole series of matter penetrating radiation types at the construction of a spallation neutron source which the Kernforschungsanlage Juelich will realize in agreement with its associated. This new big science device for the fundamental research in the Federal Republic of Germany shall as the most modern and intense source of neutrons, protons, pions, muons, and neutrinos permits to proceed in the fields of solid state physics, chemistry, molecular biology, intermediate-energy nuclear physics, radiochemistry and radiopharmacology, medicine, and materials science to virgin territory and to provide top research. All interested German groups of researchers and also scientists of foreign countries shall be able to work with this directive big science device.

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)

Validation of Monte Carlo simulation of neutron production in a spallation experiment

Czech Academy of Sciences Publication Activity Database

Zavorka, L.; Adam, Jindřich; Artiushenko, M.; Baldin, A. A.; Brudanin, V. B.; Katovsky, K.; Suchopár, M.; Svoboda, Ondřej; Vrzalová, Jitka; Wagner, Vladimír

2015-01-01

Roč. 80, JUN (2015), s. 178-187 ISSN 0306-4549 R&D Projects: GA MŠk LA08002; GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : accelerator-driven systems * uranium spallation target * neutron emission * activation measurement * Monte Carlo simulation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.174, year: 2015

Investigation of GeV proton-induced spallation reactions

International Nuclear Information System (INIS)

Hilscher, D.; Herbach, C.-M.; Jahnke, U.

2003-01-01

A reliable and precise modeling of GeV proton-induced spallation reactions is indispensable for the design of the spallation module and the target station of future accelerator driven hybrid reactors (ADS) or spallation neutron sources (ESS), in particular, to provide precise predictions for the neutron production, the radiation damage of materials (window), and the production of radioactivity ( 3 H, 7 Be etc.) in the target medium. Detailed experimental nuclear data are needed for sensitive validations and improvements of the models, whose predictive power is strongly dependent on the correct physical description of the three main stages of a spallation reaction: (i) the Intra-Nuclear-Cascade (INC) with the fast heating of the target nucleus, (ii) the de-excitation due to pre-equilibrium emission including the possibility of multi-fragmentation, and (iii) the statistical decay of thermally excited nuclei by evaporation of light particles and fission in the case of heavy nuclei. Key experimental data for this endeavour are absolute production cross sections and energy spectra for neutrons and light charged-particles (LCPs), emission of composite particles prior and post to the attainment of an equilibrated system, distribution of excitation energies deposited in the nuclei after the INC, and fission probabilities. The correlations of these quantities are particularly important to detect and identify possible deficiencies of the theoretical modeling of the various stages of a spallation reaction. Systematic measurements of such data are furthermore needed over large ranges of target nuclei and incident proton energies. Such data has been measured with the NESSI detector. An overview of new and previous results will be given. (authors)

The Spallation Neutron Source (SNS) conceptual design shielding analysis

International Nuclear Information System (INIS)

Johnson, J.O.; Odano, N.; Lillie, R.A.

1998-03-01

The shielding design is important for the construction of an intense high-energy accelerator facility like the proposed Spallation Neutron Source (SNS) due to its impact on conventional facility design, maintenance operations, and since the cost for the radiation shielding shares a considerable part of the total facility costs. A calculational strategy utilizing coupled high energy Monte Carlo calculations and multi-dimensional discrete ordinates calculations, along with semi-empirical calculations, was implemented to perform the conceptual design shielding assessment of the proposed SNS. Biological shields have been designed and assessed for the proton beam transport system and associated beam dumps, the target station, and the target service cell and general remote maintenance cell. Shielding requirements have been assessed with respect to weight, space, and dose-rate constraints for operating, shutdown, and accident conditions. A discussion of the proposed facility design, conceptual design shielding requirements calculational strategy, source terms, preliminary results and conclusions, and recommendations for additional analyses are presented

Spallation production of neutron deficient radioisotopes in North America

International Nuclear Information System (INIS)

Jamriska, D.J.; Peterson, E.J.; Carty, J.

1997-01-01

The US Department of Energy produces a number of neutron deficient radioisotopes by high energy proton induced spallation reactions in accelerators at Los Alamos National Laboratory in New Mexico and Brookhaven National Laboratory in New York. Research isotopes are also recovered from targets irradiated at TRIUMF in British Columbia, Canada. The radioisotopes recovered are distributed for use in nuclear medicine, environmental research, physics research, and industry worldwide. In addition to the main product line of Sr-82 from either Mo or Rb targets, Cu-67 from ZnO targets, and Ge-68 and RbBr targets, these irradiation facilities also produce some unique isotopes in quantities not available from any other source such as Al-26, Mg-28, Si-32, Ti-44, Fe-52, Gd-148, and Hg-194. The authors will describe the accelerator irradiation facilities at the Los Alamos and Brookhaven National Laboratories. The high level radiochemical processing facilities at Los Alamos and brief chemical processes will be described

The performance of neutron spectrometers AR a long-pulse spallation source

International Nuclear Information System (INIS)

Pynn, R.; Daemen, L.L.

1995-01-01

At a recent workshop at Lawrence Berkeley National Laboratory members of the international neutron scattering community discussed the performance to be anticipated from neutron scattering instruments installed at a 1 MW long-pulse spallation source (LPSS). Although the report of this workshop is long, its principal conclusions can be easily summarised and almost as easily understood. This article presents such a synthesis for a 60 Hz LPSS with 1 msec proton pulses. We discuss some of the limitations of the workshop conclusions and suggest a simple analysis of the performance differences that might be expected between short- and long-pulse sources both of which exploit coupled moderators

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)

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.)

Proceedings of the workshop on neutron instrumentation for a long-pulse spallation source

International Nuclear Information System (INIS)

Alonso, J.; Schroeder, L.; Pynn, R.

1995-01-01

This workshop was carried out under the auspices of the Lawrence Berkeley National Laboratory Pulsed Spallation Source activity and its Pulsed Spallation Source Committee (PSSC). One of our activities has been the sponsorship of workshops related to neutron production by pulsed sources. At the Crystal City PSSC meeting a decision was made to hold a workshop on the instrumentation opportunities at a long-pulse spallation source (LPSS). The enclosed material represents the results of deliberations of the three working groups into which the participants were divided, covering elastic scattering, inelastic scattering and fundamental physics, as well as contributions from individual participants. We hope that the material in this report will be useful to the neutron scattering community as it develops a road-map for future neutron sources. The workshop was held at LBNL in mid-April with about sixty very dedicated participants from the US and abroad. This report presents the charge for the workshop: Based on the bench mark source parameters provided by Gary Russell, determine how a suite of spectrometers in each of the three working group's area of expertise would perform at an LPSS and compare this performance with that of similar spectrometers at a continuous source or a short-pulse source. Identify and discuss modifications to these spectrometers that would enhance their performance at an LPSS. Identify any uncertainties in the analysis of spectrometer performance that require further research. Describe what R ampersand D is needed to resolve these issues. Discuss how the performance of instruments would be affected by changes in source parameters such as repetition rate, proton pulse length, and the characteristic time of pulse tails. Identify beneficial changes that could become goals for target/moderator designers. Identify novel methods that might be applied at an LPSS. Selected papers are indexed separately for inclusion in the Energy Science and Technology

Importance of delayed neutron data in transmutation system

International Nuclear Information System (INIS)

Tsujimoto, Kazufumi

1999-01-01

The accelerator-driven transmutation system has been studied at the Japan Atomic Energy Research Institute. This system is a hybrid system which consists of a high intensity accelerator, a spallation target and a subcritical core region. The subcritical core is driven by neutrons generated by spallation reaction in the target region. There is no control rod in this system, so the power is controlled only by proton beam current. The beam current to keep constant power change with effective multiplication factor of subcritical core. So, the evaluation of delayed neutron fraction which is strongly connected to the measurement of subcritical level is important factor in operation of accelerator-driven system. In this paper, important nuclides for the delayed neutron fraction of ADS will be discussed, moreover, present state of delayed neutron data in evaluated nuclear data library is presented. (author)

MEGAPIE, a 1 MW pilot experiment for a liquid metal spallation target

Energy Technology Data Exchange (ETDEWEB)

Bauer, G.S. [Paul Scherrer Institut, Spallation Neutron Source Division, Villigen-PSI (Switzerland); Salvatores, M. [CEA Cadarache, Direction des Reacteurs Nucleaires, Saint-Paul-lez-Durance Cedex (France); Heusener, G. [Forschungszentrum Karlsruhe, Projekt Nukleare Sicherheitsforschung, Karlsruhe (Germany)

2001-03-01

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)

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)

Present status of spallation target development. JAERI/KEK Joint Project

International Nuclear Information System (INIS)

Hino, R.; Kaminaga, M.; Haga, K.

2001-01-01

The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a plan to construct a neutron scattering facility under the JAERI/KEK Joint Project. Design and R and D works are being carried out vigorously for realizing the mercury target system consisting of the mercury target, moderators and reflectors working as a spallation neutron source, as well as a remote handling system for exchanging such components which will be highly irradiated. This report introduces an outline of the present status of design and development activities on the spallation target system. (author)

Characterization of Crystallographic Structures Using Bragg-Edge Neutron Imaging at the Spallation Neutron Source

Directory of Open Access Journals (Sweden)

Gian Song

2017-12-01

Full Text Available Over the past decade, wavelength-dependent neutron radiography, also known as Bragg-edge imaging, has been employed as a non-destructive bulk characterization method due to its sensitivity to coherent elastic neutron scattering that is associated with crystalline structures. Several analysis approaches have been developed to quantitatively determine crystalline orientation, lattice strain, and phase distribution. In this study, we report a systematic investigation of the crystal structures of metallic materials (such as selected textureless powder samples and additively manufactured (AM Inconel 718 samples, using Bragg-edge imaging at the Oak Ridge National Laboratory (ORNL Spallation Neutron Source (SNS. Firstly, we have implemented a phenomenological Gaussian-based fitting in a Python-based computer called iBeatles. Secondly, we have developed a model-based approach to analyze Bragg-edge transmission spectra, which allows quantitative determination of the crystallographic attributes. Moreover, neutron diffraction measurements were carried out to validate the Bragg-edge analytical methods. These results demonstrate that the microstructural complexity (in this case, texture plays a key role in determining the crystallographic parameters (lattice constant or interplanar spacing, which implies that the Bragg-edge image analysis methods must be carefully selected based on the material structures.

Utilization of Monte Carlo Calculations in Radiation Transport Analyses to Support the Design of the U.S. Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Johnson, J.O.

2000-01-01

The Department of Energy (DOE) has given the Spallation Neutron Source (SNS) project approval to begin Title I design of the proposed facility to be built at Oak Ridge National Laboratory (ORNL) and construction is scheduled to commence in FY01 . The SNS initially will consist of an accelerator system capable of delivering an ∼0.5 microsecond pulse of 1 GeV protons, at a 60 Hz frequency, with 1 MW of beam power, into a single target station. The SNS will eventually be upgraded to a 2 MW facility with two target stations (a 60 Hz station and a 10 Hz station). The radiation transport analysis, which includes the neutronic, shielding, activation, and safety analyses, is critical to the design of an intense high-energy accelerator facility like the proposed SNS, and the Monte Carlo method is the cornerstone of the radiation transport analyses

Reliability model of SNS linac (spallation neutron source-ORNL)

International Nuclear Information System (INIS)

Pitigoi, A.; Fernandez, P.

2015-01-01

A reliability model of SNS LINAC (Spallation Neutron Source at Oak Ridge National Laboratory) has been developed using risk spectrum reliability analysis software and the analysis of the accelerator system's reliability has been performed. The analysis results have been evaluated by comparing them with the SNS operational data. This paper presents the main results and conclusions focusing on the definition of design weaknesses and provides recommendations to improve reliability of the MYRRHA ( linear accelerator. The reliability results show that the most affected SNS LINAC parts/systems are: 1) SCL (superconducting linac), front-end systems: IS, LEBT (low-energy beam transport line), MEBT (medium-energy beam transport line), diagnostics and controls; 2) RF systems (especially the SCL RF system); 3) power supplies and PS controllers. These results are in line with the records in the SNS logbook. The reliability issue that needs to be enforced in the linac design is the redundancy of the systems, subsystems and components most affected by failures. For compensation purposes, there is a need for intelligent fail-over redundancy implementation in controllers. Enough diagnostics has to be implemented to allow reliable functioning of the redundant solutions and to ensure the compensation function

Thin and thick target benchmark investigations to validate spallation physics models

International Nuclear Information System (INIS)

Filges, D.; Neef, R.D.; Goldenbaum, F.; Nuenighoff, K.; Galin, J.; Letourneau, A.; Lott, B.; Patois, Y.; Schroeder, W.N.

1999-01-01

In the ESS (European Spallation Source) study report several areas have been identified where further spallation physics research and code validation is urgently needed: Neutron and charged particle production and multiplicities above one GeV incident protons, energy deposition and heating, material damage parameters, radioactivity and after heat, and high energy source shielding. All simulation calculations will be done using the Juelich HERMES code system. For this purpose various collaborations were organised. One of the collaborations is NESSI (Neutron Scintillator Silicon Detector), which concerns fundamental data as cross-section measurements on neutron multiplicities and charged particles for different ESS relevant materials. (author)

Frequency domain Monte Carlo simulation method for cross power spectral density driven by periodically pulsed spallation neutron source using complex-valued weight Monte Carlo

International Nuclear Information System (INIS)

Yamamoto, Toshihiro

2014-01-01

Highlights: • The cross power spectral density in ADS has correlated and uncorrelated components. • A frequency domain Monte Carlo method to calculate the uncorrelated one is developed. • The method solves the Fourier transformed transport equation. • The method uses complex-valued weights to solve the equation. • The new method reproduces well the CPSDs calculated with time domain MC method. - Abstract: In an accelerator driven system (ADS), pulsed spallation neutrons are injected at a constant frequency. The cross power spectral density (CPSD), which can be used for monitoring the subcriticality of the ADS, is composed of the correlated and uncorrelated components. The uncorrelated component is described by a series of the Dirac delta functions that occur at the integer multiples of the pulse repetition frequency. In the present paper, a Monte Carlo method to solve the Fourier transformed neutron transport equation with a periodically pulsed neutron source term has been developed to obtain the CPSD in ADSs. Since the Fourier transformed flux is a complex-valued quantity, the Monte Carlo method introduces complex-valued weights to solve the Fourier transformed equation. The Monte Carlo algorithm used in this paper is similar to the one that was developed by the author of this paper to calculate the neutron noise caused by cross section perturbations. The newly-developed Monte Carlo algorithm is benchmarked to the conventional time domain Monte Carlo simulation technique. The CPSDs are obtained both with the newly-developed frequency domain Monte Carlo method and the conventional time domain Monte Carlo method for a one-dimensional infinite slab. The CPSDs obtained with the frequency domain Monte Carlo method agree well with those with the time domain method. The higher order mode effects on the CPSD in an ADS with a periodically pulsed neutron source are discussed

In situ polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source.

Science.gov (United States)

Tong, X; Jiang, C Y; Lauter, V; Ambaye, H; Brown, D; Crow, L; Gentile, T R; Goyette, R; Lee, W T; Parizzi, A; Robertson, J L

2012-07-01

We report on the in situ polarized (3)He neutron polarization analyzer developed for the time-of-flight Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. Using the spin exchange optical pumping method, we achieved a (3)He polarization of 76% ± 1% and maintained it for the entire three-day duration of the test experiment. Based on transmission measurements with unpolarized neutrons, we show that the average analyzing efficiency of the (3)He system is 98% for the neutron wavelength band of 2-5 Å. Using a highly polarized incident neutron beam produced by a supermirror bender polarizer, we obtained a flipping ratio of >100 with a transmission of 25% for polarized neutrons, averaged over the wavelength band of 2-5 Å. After the cell was depolarized for transmission measurements, it was reproducibly polarized and this performance was maintained for three weeks. A high quality polarization analysis experiment was performed on a reference sample of Fe/Cr multilayer with strong spin-flip off-specular scattering. Using a combination of the position sensitive detector, time-of-flight method, and the excellent parameters of the (3)He cell, the polarization analysis of the two-dimensional maps of reflected, refracted, and off-specular scattered intensity above and below the horizon were obtained, simultaneously.

The Development of Automatic Sequences for the RF and Cryogenic Systems at the Spallation Neutron Source

International Nuclear Information System (INIS)

Gurd, Pamela; Casagrande, Fabio; Mccarthy, Michael; Strong, William; Ganni, Venkatarao

2005-01-01

Automatic sequences both ease the task of operating a complex machine and ensure procedural consistency. At the Spallation Neutron Source project (SNS), a set of automatic sequences have been developed to perform the start up and shut down of the high power RF systems. Similarly, sequences have been developed to perform backfill, pump down, automatic valve control and energy management in the cryogenic system. The sequences run on Linux soft input-output controllers (IOCs), which are similar to ordinary EPICS (Experimental Physics and Industrial Control System) IOCs in terms of data sharing with other EPICS processes, but which share a Linux processor with other such processors. Each sequence waits for a command from an operator console and starts the corresponding set of instructions, allowing operators to follow the sequences either from an overview screen or from detail screens. We describe each system and our operational experience with it.

Commissioning of the Superconducting Linac at the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Kim, Sang-Ho; Campisi, Isidoro E.

2007-01-01

The use of superconducting radiofrequency (SRF) cavities in particle accelerator is becoming more widespread. Among the projects that make use of that technology is the Spallation Neutron Source, where H-ions are accelerated to about 1 GeV, mostly making use of niobium elliptical cavities. SNS will use the accelerated short (about 700 ns) sub-bunches of protons to generate neutrons by spallation, which will in turn allow probing structural and magnetic properties of new and existing materials. The SNS superconducting linac is the largest application of RF superconductivity to come on-line in the last decade. The SRF cavities, operated at 805 MHz, were designed, built and integrated into cryomodules at Jefferson Lab and installed and tested at SNS. SNS is also the first proton-like accelerator which uses SRF cavities in a pulse mode. Many of the details of the cavity performance are peculiar to this mode of operation, which is also being applied to lepton accelerators (TESLA test facility and X-FEL at DESY and the international linear collider project). Thanks to the low frequency of the SNS superconducting cavities, operation at 4.2 K has been possible without beam energy degradation, even though the cavities and cryogenic systems were originally designed for 2.1 K operation. The testing of the superconducting cavities, the operating experience with beam and the performance of the superconducting linac will be presented

The continued development of the Spallation Neutron Source external antenna H- ion source

International Nuclear Information System (INIS)

Welton, R. F.; Carmichael, J.; Fuga, R.; Goulding, R. H.; Han, B.; Kang, Y.; Lee, S. W.; Murray, S. N.; Pennisi, T.; Potter, K. G.; Santana, M.; Stockli, M. P.; Desai, N. J.

2010-01-01

The U.S. Spallation Neutron Source (SNS) is an accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to ensure that the SNS will meet its operational commitments as well as provide for future facility upgrades with high reliability, we are developing a rf-driven, H - ion source based on a water-cooled, ceramic aluminum nitride (AlN) plasma chamber. To date, early versions of this source have delivered up to 42 mA to the SNS front end and unanalyzed beam currents up to ∼100 mA (60 Hz, 1 ms) to the ion source test stand. This source was operated on the SNS accelerator from February to April 2009 and produced ∼35 mA (beam current required by the ramp up plan) with availability of ∼97%. During this run several ion source failures identified reliability issues, which must be addressed before the source re-enters production: plasma ignition, antenna lifetime, magnet cooling, and cooling jacket integrity. This report discusses these issues, details proposed engineering solutions, and notes progress to date.

Tensile mechanical properties of a stainless steel irradiated up to 19 dpa in the Swiss spallation neutron source

Energy Technology Data Exchange (ETDEWEB)

Saito, Shigeru, E-mail: saito.shigeru@jaea.go.jp [JAEA, J-PARC Center, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Kikuchi, Kenji [Ibaraki Univ., iFRC, Tokai-mura, Ibaraki-ken 319-1106 (Japan); Hamaguchi, Dai [JAEA, J-PARC Center, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Usami, Kouji; Endo, Shinya; Ono, Katsuto; Matsui, Hiroki [JAEA, Dept. of Hot Laboratories, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Kawai, Masayoshi [KEK, Tsukuba-shi, Ibaraki-ken 305-0801 (Japan); Dai, Yong [PSI, Spallation Source Division, Villigen PSI (Switzerland)

2012-12-15

To evaluate the lifetime of the beam window of an accelerator-driven transmutation system (ADS), post irradiation examination (PIE) of the STIP (SINQ target irradiation program, SINQ; Swiss spallation neutron source) specimens was carried out. The specimens tested in this study were made from the austenitic steel Japan primary candidate alloy (JPCA). The specimens were irradiated at SINQ Target 4 (STIP-II) with high-energy protons and spallation neutrons. The irradiation conditions were as follows: the proton energy was 580 MeV, irradiation temperatures ranged from 100 to 430 Degree-Sign C, and displacement damage levels ranged from 7.1 to 19.5 dpa. Tensile tests were performed in air at room temperature (RT), 250 Degree-Sign C and 350 Degree-Sign C. Fracture surface observation after the tests was done by Scanning electron microscope (SEM). Results of the tensile tests performed at R.T. showed the extra hardening of JPCA at higher dose compared to the fission neutron irradiated data. At the higher temperatures, 250 Degree-Sign C and 350 Degree-Sign C, the extra hardening was not observed. Degradation of ductility bottomed around 10 dpa, and specimens kept their ductility until 19.5 dpa. All specimens fractured in ductile manner.

A Very Intense Neutrino Super Beam Experiment for Leptonic CP Violation Discovery based on the European Spallation Source Linac: A Snowmass 2013 White Paper

CERN Document Server

Baussan, E; Bogomilov, M.; Bouquerel, E.; Cederkäll, J.; Christiansen, P.; Coloma, P.; Cupial, P.; Danared, H.; Densham, C.; Dracos, M.; Ekelöf, T.; Eshraqi, M.; Fernandez Martinez, E.; Gaudiot, G.; Hall-Wilton, R.; Koutchouk, J.P.; Lindroos, M.; Matev, R.; McGinnis, D.; Mezzetto, M.; Miyamoto, R.; Mosca, L.; Ohlsson, T.; Öhman, H.; Osswald, F.; Peggs, S.; Poussot, P.; Ruber, R.; Tang, J.Y.; Tsenov, R.; Vankova-Kirilova, G.; Vassilopoulos, N.; Wildner, E.; Wurtz, J.

2014-01-01

Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few $\\mu$s with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground ...

Deriving profiles of incident and scattered neutrons for TOF experiments with the spallation sources

International Nuclear Information System (INIS)

Watanabe, Hidehiro

1993-01-01

A formula that closely matches the incident profile of epi-thermal and thermal neutrons for time of flight experiments carried out with a spallation neutron source and moderator scheme is derived based on the slowing-down and diffusing-out processes in a moderator. This analytical description also enables us to predict burst-function profiles; these profiles are verified by a comparison with a diffraction pattern. The limits of the analytical model are discussed through the predictable peak position shift brought about by the slowing-down process. (orig.)

New perspectives from new generations of neutron sources

International Nuclear Information System (INIS)

Mezei, F.

2007-01-01

Since the early fifties the vital multidisciplinary progress in understanding condensed matter is, in a substantial fraction, based on results of neutron scattering experiments. Neutron scattering is an inherently intensity limited method and after 50 years of considerable advance - primarily achieved by improving the scattering instruments - the maturation of the technique of pulsed spallation sources now opens up the way to provide more neutrons with improved cost and energy efficiency. A quantitative analysis of the figure-of-merit of the specialized instruments for pulsed source operation shows that up to 2 orders of magnitude intensity gains can be achieved in the next decade, with the advent of high power spallation sources. The first stations on this road, the MW class short pulse spallation sources SNS in the Usa (under commissioning), and J-PARC in Japan (under construction) will be followed by the 5 MW long pulse European Spallation Source (ESS). Further progress, that can be envisaged on the longer term, could amount to as much as another factor of 10 improvement. (author)

New perspectives from new generations of neutron sources

Science.gov (United States)

Mezei, Ferenc

2007-09-01

Since the early 1950s the vital multidisciplinary progress in understanding condensed matter is, in a substantial fraction, based on results of neutron scattering experiments. Neutron scattering is an inherently intensity limited method and after 50 years of considerable advance—primarily achieved by improving the scattering instruments—the maturation of the technique of pulsed spallation sources now opens up the way to provide more neutrons with improved cost and energy efficiency. A quantitative analysis of the figure-of-merit of the specialized instruments for pulsed source operation shows that up to 2 orders of magnitude intensity gains can be achieved in the next decade, with the advent of high power spallation sources. The first stations on this road, the MW class short pulse spallation sources SNS in the USA (under commissioning), and J-PARC in Japan (under construction) will be followed by the 5 MW long pulse European Spallation Source (ESS). Further progress, that can be envisaged on the longer term, could amount to as much as another factor of 10 improvement. To cite this article: F. Mezei, C. R. Physique 8 (2007).

Neutron production enhancements for the Intense Pulsed Neutron Source.

Energy Technology Data Exchange (ETDEWEB)

Iverson, E. B.

1999-01-04

The Intense Pulsed Neutron Source (IPNS) was the first high energy spallation neutron source in the US dedicated to materials research. It has operated for sixteen years, and in that time has had a very prolific record concerning the development of new target and moderator systems for pulsed spallation sources. IPNS supports a very productive user program on its thirteen instruments, which are oversubscribed by more than two times, meanwhile having an excellent overall reliability of 95%. Although the proton beam power is relatively low at 7 kW, the target and moderator systems are very efficient. The typical beam power which gives an equivalent flux for long-wavelength neutrons is about 60 kW, due to the use of a uranium target and liquid and solid methane moderators, precluded at some sources due to a higher accelerator power. The development of new target and moderator systems is by no means stagnant at IPNS. They are presently considering numerous enhancements to the target and moderators that offer prospects for increasing the useful neutron production by substantial factors. Many of these enhancements could be combined, although their combined benefit has not yet been well established. Meanwhile, IPNS is embarking on a coherent program of study concerning these improvements and their possible combination and implementation. Moreover, any improvements accomplished at IPNS would immediately increase the performance of IPNS instruments.

Neutron production enhancements for the Intense Pulsed Neutron Source

International Nuclear Information System (INIS)

Iverson, E. B.

1999-01-01

The Intense Pulsed Neutron Source (IPNS) was the first high energy spallation neutron source in the US dedicated to materials research. It has operated for sixteen years, and in that time has had a very prolific record concerning the development of new target and moderator systems for pulsed spallation sources. IPNS supports a very productive user program on its thirteen instruments, which are oversubscribed by more than two times, meanwhile having an excellent overall reliability of 95%. Although the proton beam power is relatively low at 7 kW, the target and moderator systems are very efficient. The typical beam power which gives an equivalent flux for long-wavelength neutrons is about 60 kW, due to the use of a uranium target and liquid and solid methane moderators, precluded at some sources due to a higher accelerator power. The development of new target and moderator systems is by no means stagnant at IPNS. They are presently considering numerous enhancements to the target and moderators that offer prospects for increasing the useful neutron production by substantial factors. Many of these enhancements could be combined, although their combined benefit has not yet been well established. Meanwhile, IPNS is embarking on a coherent program of study concerning these improvements and their possible combination and implementation. Moreover, any improvements accomplished at IPNS would immediately increase the performance of IPNS instruments

MEGAPIE-TEST: A European Project on Spallation Target Testing

International Nuclear Information System (INIS)

Knebel, Joachim U.; Klein, Jean-Christophe; Gorse, Dominique; Agostini, Pietro; Groeschel, Friedrich; Kupschus, Peter; Kirchner, Thomas; Vogt, Jean-Bernard

2002-01-01

Within the Euratom 5. Framework Programme (5FP) the European Commission is funding the MEGAPIE-TEST Project (Megawatt Pilot Experiment - Testing) over a period of three years, starting in September 2001. The project is combining the efforts of 8 main associations. MEGAPIE is a liquid metal spallation target of 1 MW of beam power. The main results of the MEGAPIE-TEST project will be: Development and comprehensive testing of a liquid metal spallation target both under beam-off and beam-on conditions, and the set up of a handbook on the design of a neutron spallation source in general. The operation of MEGAPIE within the accelerator complex SINQ at Paul Scherrer Institute (PSI), Switzerland, is envisaged in 2004. MEGAPIE is a first decisive step to realize a liquid metal spallation target in Europe. This report is giving an overview of the MEGAPIE-TEST Project, the overall work plan, and preliminary results from the design support and validation, which form an important basis for the project. (authors)

HEKATE—A novel grazing incidence neutron scattering concept for the European Spallation Source

Science.gov (United States)

Glavic, Artur; Stahn, Jochen

2018-03-01

Structure and magnetism at surfaces and buried interfaces on the nanoscale can only be accessed by few techniques, one of which is grazing incidence neutron scattering. While the technique has its strongest limitation in a low signal and large background, due to the low scattering probability and need for high resolution, it can be expected that the high intensity of the European Spallation Source in Lund, Sweden, will make many more such studies possible, warranting a dedicated beamline for this technique. We present an instrument concept, Highly Extended K range And Tunable Experiment (HEKATE), for surface scattering that combines the advantages of two Selene neutron guides with unique capabilities of spatially separated distinct wavelength frames. With this combination, it is not only possible to measure large specular reflectometry ranges, even on free liquid surfaces, but also to use two independent incident beams with tunable sizes and resolutions that can be optimized for the specifics of the investigated samples. Further the instrument guide geometry is tuned for reduction of high energy particle background and only uses low to moderate supermirror coatings for high reliability and affordable cost.

HEKATE-A novel grazing incidence neutron scattering concept for the European Spallation Source.

Science.gov (United States)

Glavic, Artur; Stahn, Jochen

2018-03-01

Structure and magnetism at surfaces and buried interfaces on the nanoscale can only be accessed by few techniques, one of which is grazing incidence neutron scattering. While the technique has its strongest limitation in a low signal and large background, due to the low scattering probability and need for high resolution, it can be expected that the high intensity of the European Spallation Source in Lund, Sweden, will make many more such studies possible, warranting a dedicated beamline for this technique. We present an instrument concept, Highly Extended K range And Tunable Experiment (HEKATE), for surface scattering that combines the advantages of two Selene neutron guides with unique capabilities of spatially separated distinct wavelength frames. With this combination, it is not only possible to measure large specular reflectometry ranges, even on free liquid surfaces, but also to use two independent incident beams with tunable sizes and resolutions that can be optimized for the specifics of the investigated samples. Further the instrument guide geometry is tuned for reduction of high energy particle background and only uses low to moderate supermirror coatings for high reliability and affordable cost.

Options for a next generation neutron source for neutron scattering based on the projected linac facility at JAERI

International Nuclear Information System (INIS)

Mezei, F.; Watanabe, Noboru; Niimura, Nobuo; Morii, Yukio; Aizawa, Kazuya; Suzuki, Jun-ichi.

1997-03-01

Japan Atomic Energy Research Institute (JAERI) has a project to construct a high intensity proton accelerator to promote wide basic science using neutrons and nuclear power technologies such as radioactive nuclide transmutation. One of the most important field for utilization of neutron beam is neutron scattering. The energy and the averaged current obtained by the proton accelerator are 1.5 GeV and 4-5.3 mA, respectively and these provide 6-8 MW power. The repetition frequency is 50-60 Hz. Evaluation of options for the use of accelerators for neutron production for neutron scattering research and investigation of the neutron research opportunities offered by sharing the superconducting linac planned at JAERI were discussed. There are two ways of the utilization of proton beams for neutron scattering experiment. One is for long pulse spallation source (LPSS) and the other is for short pulse spallation source (SPSS). Quantitative evaluation of instrument performance with LPSS and SPSS was examined in the intensive discussion, calculations, workshop on this topics with Prof. F. Mezei who stayed at JAERI from October 24 to November 6, 1996. A report of the collaborative workshop will be also published separately. (author)

Bench mark spectra for high-energy neutron dosimetry

International Nuclear Information System (INIS)

Dierckx, R.

1986-01-01

To monitor radiation damage experiments, activation detectors are commonly used. The precision of the results obtained by the multiple foil analysis is largely increased by the intercalibration in bench-mark spectra. This technique is already used in dosimetry measurements for fission reactors. To produce neutron spectra similar to fusion reactor and high-energy high-intensity neutron sources (d-Li or spallation), accelerators can be used. Some possible solutions as p-Be and d-D 2 O neutron sources, useful as bench-mark spectra are described. (author)

Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 1: Workshop summary

International Nuclear Information System (INIS)

Schroeder, L.; Leung, K.N.; Alonso, J.

1994-10-01

The workshop reviewed the ion-source requirements for high-power accelerator-driven spallation neutron facilities, and the performance of existing ion sources. Proposals for new facilities in the 1- to 5-MW range call for a widely differing set of ion-source requirements. For example, the source peak current requirements vary from 40 mA to 150 mA, while the duty factor ranges from 1% to 9%. Much of the workshop discussion centered on the state-of-the-art of negative hydrogen ion source (H - ) technology and the present experience with Penning and volume sources. In addition, other ion source technologies, for positive ions or CW applications were reviewed. Some of these sources have been operational at existing accelerator complexes and some are in the source-development stage on test stands

Overview of the Spallation Neutron Source Linac Low-Level RF Control System

CERN Document Server

Champion, Mark; Doolittle, Lawrence; Kasemir, Kay-Uwe; Ma, Hengjie; Piller, Maurice; Ratti, Alessandro

2005-01-01

The design and production of the Spallation Neutron Source Linac Low-Level RF control system is complete, and installation will be finished in Spring 2005. The warm linac beam commissioning run in Fall 2004 was the most extensive test to date of the LLRF control system, with fourteen (of an eventual 96) systems operating simultaneously. In this paper we present an overview of the LLRF control system, the experience in designing, building and installing the system, and operational results.

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

Science.gov (United States)

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

2011-02-14

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

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

Spallation reactions - physics and applications

International Nuclear Information System (INIS)

Kelic, A.; Ricciardi, M.; Schmidt, K-H.

2009-01-01

Spallation reactions have become an ideal tool for studying the equation of state and thermal instabilities of nuclear matter. In astrophysics, the interactions of cosmic rays with the interstellar medium have to be understood in detail for deducing their original composition and their production mechanisms. Renewed interest in spallation reactions with protons around 1 GeV came up recently with the developments of spallation neutron sources. The project of an accelerator-driven system (ADS) as a technological solution for incinerating the radioactive waste even intensified the efforts for better understanding the physics involved in the spallation process. Experiments on spallation reactions were performed for determining the production cross sections and properties of particles, fragments and heavy residues. Traditional experiments on heavy residues, performed in direct kinematics, were limited to the direct observation of long-lived radioactive nuclides and did not provide detailed information on the kinematics of the reaction. Therefore, an innovative experimental method has been developed, based on inverse kinematics, which allowed to identify all reaction residues in-flight, using the high resolution magnetic spectrometer FRS of GSL Darmstadt. It also gives direct access to the reaction kinematics. An experimental campaign has been carried out in a Europe-wide collaboration, investigating the spallation of several nuclei ranging from 56 Fe to 238 U Complementary experiments were performed with a full-acceptance detection system, yielding total fission cross sections. Recently, another detection system using the large acceptance ALADIN dipole and the LAND neutron detector was introduced to measure light particles in coincidence with the heavy residues. Another intense activity was dedicated to developing codes, which cover nuclear reactions occurring in an ADS. The first phase of the reaction is successfully described by a sequence of quasi-free nucleon

Transmutation of 126Sn in spallation targets of accelerator-driven systems

International Nuclear Information System (INIS)

Han, Chi Young; Saito, Masaki; Sagara, Hiroshi

2009-01-01

The practical feasibility of 126 Sn transmutation in spallation targets of accelerator-driven systems was evaluated from the viewpoints of accumulation of radioactive spallation products and neutron production as well as transmutation amount of 126 Sn. A cylindrical liquid 126 Sn target whose length depends on proton beam energy was described, based on a Pb-Bi target design of accelerator-driven system being developed in JAEA. A proton beam of 1.5 GeV-20 mA was estimated to give the transmutation rate of 126 Sn 6.4 kg/yr, which corresponds to the amount of 126 Sn annually discharged in 27 LWRs of 1 GWt and 33 GWd/THM. The equilibrium radioactivity of spallation products would reach 9% of that of 126 Sn transmuted in the spallation target, and the equilibrium toxicity would be just 3%. Some parametric analyses showed that the effective half-life of 126 Sn could be reduced through a proper reduction of the target size. The 126 Sn target was calculated to produce 40 neutrons per proton of 1.5 GeV and give a neutron spectrum very similar to that of the reference Pb-Bi target. As a result, the transmutation of 126 Sn in the spallation target has a high feasibility in terms of better transmutation performance and comparable target performance. (author)

Spallation Neutron Source Accident Terms for Environmental Impact Statement Input

Energy Technology Data Exchange (ETDEWEB)

Devore, J.R.; Harrington, R.M.

1998-08-01

This report is about accidents with the potential to release radioactive materials into the environment surrounding the Spallation Neutron Source (SNS). As shown in Chap. 2, the inventories of radioactivity at the SNS are dominated by the target facility. Source terms for a wide range of target facility accidents, from anticipated events to worst-case beyond-design-basis events, are provided in Chaps. 3 and 4. The most important criterion applied to these accident source terms is that they should not underestimate potential release. Therefore, conservative methodology was employed for the release estimates. Although the source terms are very conservative, excessive conservatism has been avoided by basing the releases on physical principles. Since it is envisioned that the SNS facility may eventually (after about 10 years) be expanded and modified to support a 4-MW proton beam operational capability, the source terms estimated in this report are applicable to a 4-MW operating proton beam power unless otherwise specified. This is bounding with regard to the 1-MW facility that will be built and operated initially. See further discussion below in Sect. 1.2.

Plans for a new pulsed spallation source at Los Alamos

International Nuclear Information System (INIS)

Pynn, R.

1993-01-01

Los Alamos National Laboratory has proposed to change the emphasis of research at its Meson Physics Facility (LAWF) by buabg a new pulsed spallation source for neutron scattering research. The new source would have a beam power of about one megawatt shared between two neutron production targets, one operating at 20 Hz and the other at 40 Hz. It would make use of much of the existing proton linac and would be designed to accommodate a later upgrade to a beam power of 5 MW or so. A study of technical feasibility is underway and will be published later this year

Pulsed neutron source and instruments at neutron facility

Energy Technology Data Exchange (ETDEWEB)

Teshigawara, Makoto; Aizawa, Kazuya; Suzuki, Jun-ichi; Morii, Yukio; Watanabe, Noboru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-11-01

We report the results of design studies on the optimal target shape, target - moderator coupling, optimal layout of moderators, and neutron instruments for a next generation pulsed spallation source in JAERI. The source utilizes a projected high-intensity proton accelerator (linac: 1.5 GeV, {approx}8 MW in total beam power, compressor ring: {approx}5 MW). We discuss the target neutronics, moderators and their layout. The sources is designed to have at least 30 beam lines equipped with more than 40 instruments, which are selected tentatively to the present knowledge. (author)

New era of neutron scattering research on advanced materials

International Nuclear Information System (INIS)

Ikeda, Susumu

2001-01-01

The projects of the next generation of pulsed spallation neutron source are planed in USA, Europe and Japan. They are one order of magnitude more powerful than the most powerful existing neutron source, ISIS in UK. They offer the exciting prospects for the future, and will open the new era of neutron scattering research on advanced materials. The Japanese project is named as the 'Joint project' between JAERI and KEK on high-intensity proton accelerators. The details of the neutron science facility in the 'Joint project' and the sciences to be developed are summarized. (author)

The WNR facility - a pulsed spallation neutron source at the Los Alamos Scientific Laboratory

International Nuclear Information System (INIS)

Russell, G.J.; Lisowski, P.W.; King, N.S.P.

1978-01-01

The Weapons Neutron Research facility (WNR) at the Los Alamos Scientific Laboratory is the first operating example of a new class of pulsed neutron sources using the X(p,n)Y spallation reaction. At present, up to 10 microamperes of 800-MeV protons from the Clinton P. Anderson Meson Physics Facility (LAMPF) linear accelerator bombard a Ta target to produce an intense white-neutron spectrum from about 800 MeV to 100 keV. The Ta target can be coupled with CH 2 and H 2 O moderators to produce neutrons of lower energy. The time structure of the WNR proton beam may be varied to optimize neutron time-of-flight (TOF) measurements covering the energy range from several hundred MeV to a few meV. The neutronics of the WNR target and target/moderator configurations have been calculated from 800 MeV to 0.5 eV. About 11 neutrons per proton are predicted for the existing Ta target. Some initial neutron TOF data are presented and compared with calculations

High-power proton linac for transmuting the long-lived fission products in nuclear waste

Energy Technology Data Exchange (ETDEWEB)

Lawrence, G.P.

1991-01-01

High power proton linacs are being considered at Los Alamos as drivers for high-flux spallation neutron sources that can be used to transmute the troublesome long-lived fission products in defense nuclear waste. The transmutation scheme being studied provides a high flux (> 10{sup 16}/cm{sup 2}{minus}s) of thermal neutrons, which efficiently converts fission products to stable or short-lived isotopes. A medium-energy proton linac with an average beam power of about 110 MW can burn the accumulated Tc99 and I129 inventory at the DOE's Hanford Site within 30 years. Preliminary concepts for this machine are described. 3 refs., 5 figs., 2 tabs.

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

Beginnings of remote handling at the RAL Spallation Neutron Source

International Nuclear Information System (INIS)

Liska, D.J.; Hirst, J.

1985-01-01

Expenditure of funds and resources for remote maintenance systems traditionally are delayed until late in an accelerator's development. However, simple remote-surveillance equipment can be included early in facility planning to set the stage for future remote-handling needs and to identify appropriate personnel. Some basic equipment developed in the UK at the Spallation Neutron Source (SNS) that serves this function and that has been used to monitor beam loss during commissioning is described. A photograph of this equipment, positioned over the extractor septum magnet, is shown. This method can serve as a pattern approach to the problem of initiating remote-handling activities in other facilities

Awareness, Preference, Utilization, and Messaging Research for the Spallation Neutron Source and High Flux Isotope Reactor

International Nuclear Information System (INIS)

Bryant, Rebecca; Kszos, Lynn A.

2011-01-01

Oak Ridge National Laboratory (ORNL) offers the scientific community unique access to two types of world-class neutron sources at a single site - the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR). The 85-MW HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world, and the SNS is one of the world's most intense pulsed neutron beams. Management of these two resources is the responsibility of the Neutron Sciences Directorate (NScD). NScD commissioned this survey research to develop baseline information regarding awareness of and perceptions about neutron science. Specific areas of investigative interest include the following: (1) awareness levels among those in the scientific community about the two neutron sources that ORNL offers; (2) the level of understanding members of various scientific communities have regarding benefits that neutron scattering techniques offer; and (3) any perceptions that negatively impact utilization of the facilities. NScD leadership identified users of two light sources in North America - the Advanced Photon Source (APS) at Argonne National Laboratory and the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory - as key publics. Given the type of research in which these scientists engage, they would quite likely benefit from including the neutron techniques available at SNS and HFIR among their scientific investigation tools. The objective of the survey of users of APS, NSLS, SNS, and HFIR was to explore awareness of and perceptions regarding SNS and HFIR among those in selected scientific communities. Perceptions of SNS and FHIR will provide a foundation for strategic communication plan development and for developing key educational messages. The survey was conducted in two phases. The first phase included qualitative methods of (1) key stakeholder meetings; (2) online interviews with user administrators of APS and NSLS; and (3) one-on-one interviews

Awareness, Preference, Utilization, and Messaging Research for the Spallation Neutron Source and High Flux Isotope Reactor

Energy Technology Data Exchange (ETDEWEB)

Bryant, Rebecca [Bryant Research, LLC; Kszos, Lynn A [ORNL

2011-03-01

Oak Ridge National Laboratory (ORNL) offers the scientific community unique access to two types of world-class neutron sources at a single site - the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR). The 85-MW HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world, and the SNS is one of the world's most intense pulsed neutron beams. Management of these two resources is the responsibility of the Neutron Sciences Directorate (NScD). NScD commissioned this survey research to develop baseline information regarding awareness of and perceptions about neutron science. Specific areas of investigative interest include the following: (1) awareness levels among those in the scientific community about the two neutron sources that ORNL offers; (2) the level of understanding members of various scientific communities have regarding benefits that neutron scattering techniques offer; and (3) any perceptions that negatively impact utilization of the facilities. NScD leadership identified users of two light sources in North America - the Advanced Photon Source (APS) at Argonne National Laboratory and the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory - as key publics. Given the type of research in which these scientists engage, they would quite likely benefit from including the neutron techniques available at SNS and HFIR among their scientific investigation tools. The objective of the survey of users of APS, NSLS, SNS, and HFIR was to explore awareness of and perceptions regarding SNS and HFIR among those in selected scientific communities. Perceptions of SNS and FHIR will provide a foundation for strategic communication plan development and for developing key educational messages. The survey was conducted in two phases. The first phase included qualitative methods of (1) key stakeholder meetings; (2) online interviews with user administrators of APS and NSLS; and (3) one

Mass formula dependence of calculated spallation reaction product distributions

International Nuclear Information System (INIS)

Nishida, Takahiko; Nakahara, Yasuaki

1990-01-01

A new version of the spallation reaction simulation code NUCLEUS was developed by incorporating Uno and Yamada's mass formula. This version was used to calculate the distribution of products from the spallation of uranium nuclei by high-energy protons. The dependence of the distributions on the mass formula was examined by comparing the results with those from the original version, which is based on Cameron's mass formula and the mass table compiled by Wapstra et al. As regards the fission component of spallation products, the new version reproduces the reaction product data obtained from thin foil experiments much better, especially on the neutron excess side. (orig.) [de

Status of Cryogenic System for Spallation Neutron Source's Superconducting Radiofrequency Test Facility at Oak Ridge National Lab

International Nuclear Information System (INIS)

Xu, Ting; Casagrande, Fabio; Ganni, Venkatarao; Knudsen, Peter N.; Strong, William Herb

2011-01-01

Spallation Neutron Source (SNS) at Oak Ridge National Lab (ORNL) is building an independent cryogenic system for its Superconducting Radiofrequency Test Facility (SRFTF). The scope of the system is to support the SNS cryomodule test and cavity test at 2-K (using vacuum pump) and 4.5K for the maintenance purpose and Power Upgrade Project of SNS, and to provide the part of the cooling power needed to backup the current CHL to keep Linac at 4.5-K during CHL maintenance period in the future. The system is constructed in multiple phases. The first phase is to construct an independent 4K helium refrigeration system with helium Dewar and distribution box as load interface. It is schedule to be commissioned in 2013. Here we report the concept design of the system and the status of the first phase of this project.

H- radio frequency source development at the Spallation Neutron Source.

Science.gov (United States)

Welton, R F; Dudnikov, V G; Gawne, K R; Han, B X; Murray, S N; Pennisi, T R; Roseberry, R T; Santana, M; Stockli, M P; Turvey, M W

2012-02-01

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ∼38 mA peak current in the linac and an availability of ∼90%. H(-) beam pulses (∼1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ∼60 kW) of a copper antenna that has been encased with a thickness of ∼0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ∼99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ∼75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance∕installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ∼100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Experimental demonstration of a compact epithermal neutron source based on a high power laser

Science.gov (United States)

Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Raspino, D.; Ansell, S.; Wilson, L. A.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Kelleher, J.; Murphy, C. D.; Notley, M.; Rusby, D. R.; Schooneveld, E.; Borghesi, M.; McKenna, P.; Rhodes, N. J.; Neely, D.; Brenner, C. M.; Kar, S.

2017-07-01

Epithermal neutrons from pulsed-spallation sources have revolutionised neutron science allowing scientists to acquire new insight into the structure and properties of matter. Here, we demonstrate that laser driven fast (˜MeV) neutrons can be efficiently moderated to epithermal energies with intrinsically short burst durations. In a proof-of-principle experiment using a 100 TW laser, a significant epithermal neutron flux of the order of 105 n/sr/pulse in the energy range of 0.5-300 eV was measured, produced by a compact moderator deployed downstream of the laser-driven fast neutron source. The moderator used in the campaign was specifically designed, by the help of MCNPX simulations, for an efficient and directional moderation of the fast neutron spectrum produced by a laser driven source.

Calculated intensity of high-energy neutron beams

International Nuclear Information System (INIS)

Mustapha, B.; Nolen, J.A.; Back, B.B.

2004-01-01

The flux, energy and angular distributions of high-energy neutrons produced by in-flight spallation and fission of a 400 MeV/A 238 U beam and by the break-up of a 400 MeV/A deuteron beam are calculated. In both cases very intense secondary neutron beams are produced, peaking at zero degrees, with a relatively narrow energy spread. Such secondary neutron beams can be produced with the primary beams from the proposed rare isotope accelerator driver linac. The break-up of a 400 kW deuteron beam on a liquid-lithium target can produce a neutron flux of >10 10 neutrons/cm 2 /s at a distance of 10 m from the target

Analysis of radiation environmental safety for China's Spallation Neutron Source (CSNS)

International Nuclear Information System (INIS)

Wang Qingbin; Wu Qingbiao; Ma Zhongjian; Zhang Qingjiang; Li Nan; Wu Jingmin; Liu Jian; Zhang Gang

2010-01-01

The China Spallation Neutron Source (CSNS) is going to be located in Dalang Town, Dongguan City in the Guangdong Province.In this paper we report the results of the parameters related with environment safety based on experiential calculations and Monte Carlo simulations. The main project of the accelerator is an under ground construction.On top there is a 0.5 m concrete and 5.0 m soil covering for shielding,which can reduce the dose out of the tunnel's top down to 0.2 μSv/h. For the residents on the boundary of the CSNS, the dose produced by skyshine, which is caused by the penetrated radiation leaking from the top of the accelerator, is no more than 0.68 μSv/a. When CSNS is operating normally, the maximal annual effective dose due to the emission of gas from the tunnel is 2.40 x 10 -3 mSv/a to the public adult, and 2.29 x 10 -3 mSv/a to a child, both values are two orders of magnitude less than the limiting value for control and management. CSNS may give rise to an activation of the soil and groundwater in the nearest tunnels, where the main productions are 3 H, 7 Be, 22 Na, 54 Mn, etc. But the specific activity is less than the exempt specific activity in the national standard GB13376-92. So it is safe to say that the environmental impact caused by the activation of soil and groundwater is insignificant. To sum up, for CSNS, as a powerful neutron source device, driven by a high-energy high-current proton accelerator, a lot of potential factors affecting the environment exist. However, as long as effective shieldings for protection are adopted and strict rules are drafted, the environmental impact can be kept under control within the limits of the national standard. (authors)

Structural design study of a proton beam window for a 1-MW spallation neutron source

CERN Document Server

Teraoku, T; Ishikura, S; Kaminaga, M; Maekawa, F; Meigo, S I; Terada, A

2003-01-01

A 1-MW spallation neutron source aiming at materials and life science researches will be constructed under the JAERI-KEK High-intensity Proton Accelerator Project (J-PARC). A proton beam passes through a proton beam window, and be injected into a target of the neutron source. The proton beam window functions as a boundary wall between a high vacuum area in the proton beam line and a helium atmosphere at about atmospheric pressure in a helium vessel which contains the target and moderators. The proton beam window is cooled by light water because high heat-density is generated in the window material by interactions with the proton beam. Then, uniformity of the water flow is requested at the window to suppress a hot-spot that causes excessive thermal stress and cooling water boiling. Also, the window has to be strong enough in its structure for inner stress due to water pressure and thermal stress due to heat generation. In this report, we propose two types of proton beam windows; one flat-type that is easy to m...

Survey on neutron production by electron beam from high power CW electron linear accelerator

International Nuclear Information System (INIS)

Toyama, S.

1999-04-01

In Japan Nuclear Cycle Development Institute, the development of high current CW electron linear accelerator is in progress. It is possible for an accelerator to produce neutrons by means of a spallation and photo nuclear reactions. Application of neutron beam produced by bremsstrahlung is one of ways of the utilization for high current electron accelerator. It is actual that many electron linear accelerators which maximum energy is higher than a few hundreds MeV are used as neutron sources. In this report, an estimate of neutron production is evaluated for high current CW electron linear accelerator. The estimate is carried out by 10 MeV beam which is maximum energy limited from the regulation and rather low for neutron production. Therefore, the estimate is also done by 17 and 35 MeV beam which is possible to be accelerated. Beryllium is considered as a target for lower electron energy in addition to Lead target for higher energy, because Beryllium has low threshold energy for neutron production. The evaluation is carried out in account of the target thickness optimized by the radiation length and neutron cross section reducing the energy loss for both of electron and neutron, so as to get the maximum number of neutrons. The result of the calculations shows neutron numbers 1.9 x 10 10 , 6.1 x 10 13 and 4.8 x 10 13 (n/s), respectively, for 10, 17, and 35 MeV with low duty. The thermal removal from the target is one of critical points. The additional shielding and cooling system is necessary in order to endure radiation. A comparison with other facilities are also carried out. The estimate of neutron numbers suggests the possibility to be applied for neutron radiography and measurement of nuclear data by means of Lead spectrometer, for example. (author)

Quasielastic high-resolution time-of-flight spectrometers employing multi-disk chopper cascades for spallation sources

International Nuclear Information System (INIS)

Lechner, R.E.

2001-01-01

The design of multi-disk chopper time-of-flight (MTOF) spectrometers for high-resolution quasielastic and low-energy inelastic neutron scattering at spallation sources is discussed in some detail. A continuously variable energy resolution (1 μeV to 10 meV), and a large dynamic range (1 μeV to 100 meV), are outstanding features of this type of instrument, which are easily achieved also at a pulsed source using state-of-the-art technology. The method of intensity-resolution optimization of MTOF spectrometers at spallation sources is treated on the basis of the requirement of using (almost) 'all the neutrons of the pulse', taking into account the constant, but wavelength-dependent duration of the source pulse. It follows, that the optimization procedure (which is slightly different from that employed in the steady-state source case) should give priority to the highest resolution, whenever such a choice becomes necessary. This leads to long monochromator distances (L l2 ) of the order of 50 m, for achieving resolutions now available at reactor sources. A few examples of spectrometer layout and corresponding design parameters for large-angle and for small-angle quasielastic scattering instruments are given. In the latter case higher energy resolution than for large-angle scattering is required and achieved. The use of phase-space transformers, neutron wavelength band-pass filters and multichromatic operation for the purpose of intensity-resolution optimization are discussed. This spectrometer can be designed to make full use of the pulsed source peak flux. Therefore, and because of a number of improvements, high resolution will be available at high intensity: for any given resolution the total intensity at the detectors, when placed at one of the planned new spallation sources (SNS, JSNS, ESS, AUSTRON) will be larger by at least three orders of magnitude than the total intensity of any of the presently existing instruments of this type in routine operation at steady

New sources and instrumentation for neutron science

International Nuclear Information System (INIS)

Gil, Alina

2011-01-01

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

New sources and instrumentation for neutron science

Energy Technology Data Exchange (ETDEWEB)

Gil, Alina, E-mail: a.gil@ajd.czest.pl [Faculty of Mathematical and Natural Sciences, JD University, Al. Armii Krajowej 13/15, 42-200 Czestochowa (Poland)

2011-04-01

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

The COHERENT Experiment at the Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Elliott, Steven Ray [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

2015-09-30

The COHERENT collaboration's primary objective is to measure coherent elastic neutrino- nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT will deploy multiple detector technologies in a phased approach: a 14-kg CsI[Na] scintillating crystal, 15 kg of p-type point-contact germanium detectors, and 100 kg of liquid xenon in a two-phase time projection chamber. Following an extensive background measurement campaign, a location in the SNS basement has proven to be neutron-quiet and suitable for deployment of the COHERENT detector suite. The simultaneous deployment of the three COHERENT detector subsystems will test the N=2 dependence of the cross section and ensure an unambiguous discovery of CEvNS. This document describes concisely the COHERENT physics motivations, sensitivity and plans for measurements at the SNS to be accomplished on a four-year timescale.

Fault-tolerant superconducting linac design for a 5-MW neutron spallation source

International Nuclear Information System (INIS)

Swain, G.R.

1993-01-01

An 805-MHz superconducting linac is proposed which could accelerate protons from 0.1 to 2.0 GeV in less than 730 m for a peak surface field in the cavities of 17 MV/m. The linac would furnish 5 MW of beam for a neutron spallation source, plus up to 10 additional MW of beam for other purposes. The design uses 454 elliptical cavities arranged in twelve groups, identical cavities being used within each group. Characterization of elliptical cavities for betas from 0.44 to 0.94 and the steps of the design procedure are presented. The effective peak power fed by each rf coupler would be less than 100 kW for all of the cavities. 6.5 kW of power at 2 deg K would need to be extracted by the cryogenic system. Space charge was found to have a negligible effect on emittance growth. The design is such that one cavity per group could be inoperable, and the gradient in the remaining cavities could be increased to compensate. The longitudinal and transverse acceptances of the linac would not be significantly degraded under such fault conditions. A corresponding 402.5 MHz linac design is being developed

Preliminary assessment of the nuclide migration from the activation zone around the proposed Spallation Neutron Source facility

International Nuclear Information System (INIS)

Dole, L.R.

1998-09-01

The purpose of this study is to investigate the potential impacts of migrating radionuclides from the activation zone around the proposed Spallation Neutron Source (SNS). Using conservatively high estimates of the potential inventory of radioactive activation products that could form in the proposed compacted-soil shield berm around an SNS facility on the Oak Ridge Reservation (ORR), a conservative, simplified transport model was used to estimate the potential worst-case concentrations of the 12 long-lived isotopes in the groundwater under a site with the hydrologic characteristics of the ORR

Preliminary assessment of the nuclide migration from the activation zone around the proposed Spallation Neutron Source facility

Energy Technology Data Exchange (ETDEWEB)

Dole, L.R.

1998-09-01

The purpose of this study is to investigate the potential impacts of migrating radionuclides from the activation zone around the proposed Spallation Neutron Source (SNS). Using conservatively high estimates of the potential inventory of radioactive activation products that could form in the proposed compacted-soil shield berm around an SNS facility on the Oak Ridge Reservation (ORR), a conservative, simplified transport model was used to estimate the potential worst-case concentrations of the 12 long-lived isotopes in the groundwater under a site with the hydrologic characteristics of the ORR.

Neutron cross-sections above 20 MeV for design and modeling of ...

Indian Academy of Sciences (India)

bination of a high-power, high-energy accelerator, a spallation target for neutron ... The development of the commercial critical reactors of today motivated a large effort on nuclear data up to about 20 MeV, and presently ..... facility in the world.

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...

Spallation radiation damage and dosimetry for accelerator transmutation of waste applications

International Nuclear Information System (INIS)

Wechsler, M.S.; Lin, C.

1993-01-01

Proposals are currently being made for systems to treat radioactive waste based on the use of accelerator-driven neutron sources. A linear proton accelerator with energies as high as 1600 MeV and currents up to 250 ma are anticipated for the driver. The neutron fluxes may reach up to 10 20 neutrons/m 2 s as generated by the spallation reactions that occur when the protons strike target materials. Calculations are described to determine radiation fluxes and flux spectra inherent in such systems and to estimate likely radiation effects on system components. The calculations use LAHET, a Monte Carlo high-energy transport code, and MCNP, a generalized-geometry, coupled neutron-photon Monte Carlo transport code. Cross sections for displacement and helium production are presented for spallation neutrons of energies from 21 MeV to 1600 MeV for Inconel 718 (Ni plus 18.5, 18.5, 5.1, and 3 wt % of Cr, Fe, Nb, and Mo, respectively), an alloy that is used for the proton beam entry window in several accelerators. In addition, results for this alloy are presented for the primary knocked-on atom (PKA) spectrum and the transmutation yield for 1600 MeV incident neutrons

Design of the MYRRHA Spallation Target Assembly

International Nuclear Information System (INIS)

Keijers, S.; Fernandez, R.; Stankovskiy, A.; Kennedy, G.; Van Tichelen, K.

2015-01-01

MYRRHA (Multi-purpose hybrid Research Reactor for High-tech Applications) is a multi-purpose research facility currently being developed at SCK.CEN. MYRRHA is based on the ADS (Accelerator Driven System) concept where a proton accelerator, a spallation target and a subcritical reactor are coupled. MYRRHA will demonstrate the ADS full concept by coupling these three components at a reasonable power level. As a flexible irradiation facility, the MYRRHA research reactor will be able to work in both critical and subcritical modes. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material research for GEN IV and fusion reactors, and radioisotope production for medical and industrial applications. MYRRHA will be cooled by Lead Bismuth Eutectic (LBE) and will play an important role in the development of the Pb-alloys technology needed for the LFR (Lead Fast Reactor) GEN IV concept. This paper describes the evolution of the MYRRHA spallation target design. In the early phase of the MYRRHA project (XT-ADS), the target design was based on a dedicated spallation loop inside the primary reactor vessel. Within the core, the 3 central fuel assembly positions were occupied by the spallation target, which enabled a windowless design created by a free surface of LBE facing the proton beam. The windowless option was preferred because of high heat loads in combination with severe irradiation damage in the target region would result in unacceptably short lifetimes of a target window. The LBE in the loop served as spallation target and as target coolant, but was separated from the LBE cooling the reactor core. The loop was equipped with its own pump, heat exchanger and conditioning system. The change from cyclotron to linear accelerator allowed the increase in proton energy from 350 MeV to 600 MeV. This modification led to an important reduction of the specific heat load at the target level and an improvement of the neutronic performance. In addition to

Synchrotron-driven spallation sources

CERN Document Server

Bryant, P J

1996-01-01

The use of synchrotrons for pulsed neutron spallation sources is an example of scientific and technological spin-off from the accelerator development for particle physics. Accelerator-driven sources provide an alternative to the continuous-flux, nuclear reactors that currently furnish the majority of neutrons for research and development. Although the present demand for neutrons can be adequately met by the existing reactors, this situation is unlikely to continue due to the increasing severity of safety regulations and the declared policies of many countries to close down their reactors within the next decade or so. Since the demand for neutrons as a research tool is, in any case,expected to grow, there has been a corresponding interest in sources that are synchrotron-driven or linac-driven with a pulse compression ring and currently several design studies are being made. These accelerator-driven sources also have the advantage of a time structure with a high peak neutron flux. The basic requirement is for a...

High-current negative-ion sources for pulsed spallation neutron sources: LBNL workshop, October 1994

International Nuclear Information System (INIS)

Alonso, J.R.

1995-09-01

The neutron scattering community has endorsed the need for a high-power (1 to 5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (sub-microsecond) bursts of cold neutrons, said time structure offering advantages over the continuous flux from a reactor. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 kW source in the UK), and call for a high-current (approx. 100 mA peak) H- source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The I to 5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty-factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. The Workshop reported on here, held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H- source technologies, and identified necessary R ampersand D efforts to bridge the gap

The European Spallation Source (ESS) project

International Nuclear Information System (INIS)

Clausen, K.N.

2001-01-01

The European Spallation Source (ESS) is a proposal for a next generation neutron source in Europe. The first phase of the project - establishing the scientific case and the technical feasibility - is now followed by an intensive period of R and D activities. Three target station options: l) a 5 MW 50 Hz short pulse station, 2) a 1 MW 10 Hz short pulse station and 3) a 4 to 5 MW 16 2/3 Hz 2.5 ms long pulse station, and the use of novel advanced cold moderators will be studied. A superconducting option for the accelerator will be investigated in a Europe-wide feasibility study for a multipurpose facility (CONCERT) with potential applications in areas such as neutron scattering, high power irradiation, R and D on transmutation and radioactive beams. It will explore possible synergies of such a facility compared with a standalone solution for the ESS. The milestones for the next three years are: June 2001 - Decision on neutron parameters and target station options, June 2002 - Conclusion of the Concert multipurpose accelerator study and June 2003 - Proposal ready for submission to funding agencies. The facility could be ready for operation around 2010. (author)

Thermal stabilities and optimal operating parameters for the Oak Ridge Spallation Neutron Source superconducting linear accelerator

International Nuclear Information System (INIS)

Kim, Sang-Ho; Campisi, Isidoro E.

2007-01-01

The baseline Spallation Neutron Source (SNS) accelerator will provide a 1 GeV, 1.4 MW proton beam to a mercury target for the production of neutrons. The main acceleration for the H- beam is provided by 81 superconducting cavities installed in 23 cryomodules operating at 805 MHz. The design of the superconducting linac includes a 2.1 K, 2.5 kW cryogenic plant to maintain the cavities below the helium lambda point for efficient operation at high accelerating gradients. In this paper operating conditions are analyzed rather than the design ones, which still guarantees a high gradient operation without any temperature constraint. From the analysis it appears that the SNS superconducting linac can be operated at temperatures higher than 2.1 K, a fact resulting from both the pulsed nature of the superconducting cavities, the specific configuration of the existing cryogenic plant and the operating frequency. General conditions are also given regarding the operation of pulsed superconducting cavities resonating at different frequencies

Analysis of phase velocity designing on superconducting section of proton Linac for spallation neutron source

International Nuclear Information System (INIS)

Ouyang Huafu; Xu Taoguang; Yu Qingchang; Guan Xialing; Luo Zihua

2001-01-01

A preliminary design of superconducting section of proton linac for spallation neutron source is made, which includes the design and optimization of the cavity shape and the architecture design of the superconducting section. In addition, the choice of the cell number of the superconducting cavity, the value of the geometric β G , the optimization principles of cavity and the beam dynamic properties are discussed

Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source

International Nuclear Information System (INIS)

Abernathy, D. L.; Stone, M. B.; Loguillo, M. J.; Lucas, M. S.; Delaire, O.; Tang, X.; Lin, J. Y. Y.; Fultz, B.

2012-01-01

The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically focused neutron guide, high speed magnetic bearing choppers, and a massive array of 3 He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection.

Spallation studies at Saturne

Energy Technology Data Exchange (ETDEWEB)

Frehaut, J. [Centre d`Etudes de Bruyeres-le-Chatel (France)

1995-10-01

SATURNE is a synchrotron accelerator which can deliver particles of momentum P and charge Z up to P/Z = 4 GeV/c. Monokinetic neutron beams of momentum up to 2 GeV/c can be produced. The spallation studies deal with measurements of: (i) differential neutron production cross sections from thin targets, (ii) neutron multiplicity distribution for proton and {sup 3}He induced reactions, and (iii) nuclide production in thin target. Measurements on thick or composite targets are under consideration.

Status of Cea spallation modules for ads

International Nuclear Information System (INIS)

Enderle, R.; Poitevin, Y.; Deffain, J.P.; Bergeron, J.

2001-01-01

In the framework of CEA studies on ADS dedicated to waste transmutation, a liquid metal reference concept and an alternative solid target have been evaluated to produce neutrons inside the spallation module. This work examines the design (neutronic, thermohydraulic and mechanical aspects) and the performances of both options. It is shown that a liquid Pb-Bi target offers more possibilities regarding to high protons current densities (possible industrial extrapolation) but that a solid target made with tungsten particles offers also interesting ability to create a neutrons flux appropriated (strong spectrum and flat axial distribution) to an sub-critical core dedicated to incineration. (author)

Pulsed neutron source based on accelerator-subcritical-assembly

Energy Technology Data Exchange (ETDEWEB)

Inoue, Makoto; Noda, Akira; Iwashita, Yoshihisa; Okamoto, Hiromi; Shirai, Toshiyuki [Kyoto Univ., Uji (Japan). Inst. for Chemical Research

1997-03-01

A new pulsed neutron source which consists of a 300MeV proton linac and a nuclear fuel subcritical assembly is proposed. The proton linac produces pulsed spallation neutrons, which are multipied by the subcritical assembly. A prototype proton linac that accelerates protons up to 7MeV has been developed and a high energy section of a DAW structure is studied with a power model. Halo formations in high intensity beam are also being studied. (author)

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.

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

The National Spallation Neutron Source Collaboration: Towards a new pulsed neutron source in the United States

International Nuclear Information System (INIS)

Appleton, B.R.; Ball, J.B.; Alonso, J.R.; Gough, R.A.; Weng, W.T.; Jason, A.

1996-01-01

The US Department of Energy has commissioned Oak Ridge National Laboratory to initiate the conceptual design for a next-generation pulsed spallation neutron source. Current expectation is for a construction start in FY 1998, with commencement of operations in 2004. For this project, ORNL has entered into a collaborative arrangement with LBNL, BNL, LANL (and most recently ANL). The conceptual design study is now well underway, building on the strong base of the extensive work already performed by various Laboratories, as well as input from the user community (from special BESAC subpanels). Study progress, including accelerator configuration and plans for resolution of critical issues, is reported in this paper

An update on measurements of helium-production reactions with a spallation neutron source

International Nuclear Information System (INIS)

Haight, R.C.; Bateman, F.B.; Chadwick, M.B.

1995-01-01

This report gives the status, updated since the last Research Coordination Meeting, of alpha-particle production cross sections, emission spectra and angular distributions which we are measuring at the spallation source of fast neutrons at the Los Alamos Meson Physics Facility (LAMPF). Detectors at angles of 30, 60, 90 and 135 degrees are used to identify alpha particles, measure their energy spectra, and indicate the time-of-flight, and hence the energy, of the neutrons inducing the reaction. The useful neutron energy ranges from less than 1 MeV to approximately 50 MeV for the present experimental setup. Targets under study at present include C, N, 0, 27 Al, Si, 51 V, 56 Fe, 59 CO, 58,60 Ni, 89 Y and 93 Nb. Data for 59 Co have been re-analyzed. The results illustrate the capabilities of the approach, agreement with literature values, and comparisons with nuclear reaction model calculations

An update on measurements of helium-production reactions with a spallation neutron source

Energy Technology Data Exchange (ETDEWEB)

Haight, R.C.; Bateman, F.B.; Chadwick, M.B. [and others

1995-10-01

This report gives the status, updated since the last Research Coordination Meeting, of alpha-particle production cross sections, emission spectra and angular distributions which we are measuring at the spallation source of fast neutrons at the Los Alamos Meson Physics Facility (LAMPF). Detectors at angles of 30, 60, 90 and 135{degrees} are used to identify alpha particles, measure their energy spectra, and indicate the time-of-flight, and hence the energy, of the neutrons inducing the reaction. The useful neutron energy ranges from less than 1 MeV to approximately 50 MeV for the present experimental setup. Targets under study at present include C, N, 0, {sup 27}Al, Si, {sup 51}V, {sup 56}Fe, {sup 59}CO, {sup 58,60}Ni, {sup 89}Y and {sup 93}Nb. Data for {sup 59}Co have been re-analyzed. The results illustrate the capabilities of the approach, agreement with literature values, and comparisons with nuclear reaction model calculations.

Accelerator-based neutron source and its future

International Nuclear Information System (INIS)

Kiyanagi, Yoshiaki

2008-01-01

Neutrons are useful tool for the material science and also for the industrial applications. Now, high intensity neutron sources based on MW class big accelerators are under commissioning in Japan, Japan Spallation Neutron Source (JSNS) at J-PARC and in the US, SNS. Such high power neutron sources required the moderators that can be used under high radiation field and also give high neutronic performance. We have been performing experimental and Monte Carlo simulation studies to develop the cold neutron moderator systems for the high power sources since it is becoming important for materials and life science. Hydrogen is the unique candidate at the present stage due to its high resistibility to the radiation. It was indicated the para hydrogen moderator gave a good neutronic performance by experimental results. On the other hand, in the future, low power neutron sources are recognized to be useful to perform sprouting experiments and to promote the neutron science. The moderator systems need a concept different from the high power source. Therefore, we studied neutronic performances of the mesitylene and the methane moderators to get high intensity in a definite area on the moderator surface. Single groove moderators were studied and optimal geometry and the intensity gain were obtained. The mesitylene moderator gave a rather good performance compared to the methane moderator. (author)

Intense neutron source: high-voltage power supply specifications

International Nuclear Information System (INIS)

Riedel, A.A.

1980-08-01

This report explains the need for and sets forth the electrical, mechanical and safety specifications for a high-voltage power supply to be used with the intense neutron source. It contains sufficient information for a supplier to bid on such a power supply

H{sup -} radio frequency source development at the Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Welton, R. F.; Gawne, K. R.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Roseberry, R. T.; Santana, M.; Stockli, M. P. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471 (United States); Dudnikov, V. G. [Muons, Inc., 552 N. Batavia Avenue, Batavia, Illinois 60510 (United States); Turvey, M. W. [Villanova University, 800E. Lancaster Ave, Villanova, Pennsylvania 19085 (United States)

2012-02-15

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Fundamental physics possibilities at the European Spallation Source

DEFF Research Database (Denmark)

Klinkby, Esben Bryndt; Soldner, Torsten

2016-01-01

The construction of the European Spallation Source ESS is ongoing in Lund, Sweden. This new high power spallation source with its long-pulse structure opens up new possibilities for fundamental physics experiments. This paper focusses on two proposals for fundamental physics at the ESS: The ANNI...

Neutron fluctuations in accelerator driven and power reactors via backward master equations

International Nuclear Information System (INIS)

Zhifeng Kuang

2000-05-01

The transport of neutrons in a reactor is a random process, and thus the number of neutrons in a reactor is a random variable. Fluctuations in the number of neutrons in a reactor can be divided into two categories, namely zero noise and power reactor noise. As the name indicates, they dominate (i.e. are observable) at different power levels. The reasons for their occurrences and utilization are also different. In addition, they are described via different mathematical tools, namely master equations and the Langevin equation, respectively. Zero noise carries information about some nuclear properties such as reactor reactivity. Hence methods such as Feynman- and Rossi-alpha methods have been established to determine the subcritical reactivity of a subcritical system. Such methods received a renewed interest recently with the advent of the so-called accelerator driven systems (ADS). Such systems, intended to be used either for energy production or transuranium transmutation, will use a subcritical core with a strong spallation source. A spallation source has statistical properties that are different from those of the traditionally used radioactive sources which were also assumed in the derivation of the Feynman- and Rossi-alpha formulae. Therefore it is necessary to re-derive the Feynman- and Rossi-alpha formulae. Such formulae for ADS have been derived recently but in simpler neutronic models. One subject of this thesis is the extension of such formulae to a more general case in which six groups of delayed neutron precursors are taken into account, and the full joint statistics of the prompt and all delayed groups is included. The involved complexity problems are solved with a combination of effective analytical techniques and symbolic algebra codes. Power reactor noise carries information about parametric perturbation of the system. Langevin technique has been used to extract such information. In such a treatment, zero noise has been neglected. This is a pragmatic

Quantum molecular dynamics approach to estimate spallation yield ...

Indian Academy of Sciences (India)

Consequently, the need for reliable data to design and construct spallation neutron sources has prompted ... A major disadvantage of the QMD code .... have estimated the average neutron multiplicities per primary reaction and kinetic energy.

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.

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

Development of a high-count-rate neutron detector with position sensitivity and high efficiency

International Nuclear Information System (INIS)

Nelson, R.; Sandoval, J.

1996-01-01

While the neutron scattering community is bombarded with hints of new technologies that may deliver detectors with high-count-rate capability, high efficiency, gamma-ray insensitivity, and high resolution across large areas, only the time-tested, gas-filled 3 He and scintillation detectors are in widespread use. Future spallation sources with higher fluxes simply must exploit some of the advanced detector schemes that are as yet unproved as production systems. Technologies indicating promise as neutron detectors include pixel arrays of amorphous silicon, silicon microstrips, microstrips with gas, and new scintillation materials. This project sought to study the competing neutron detector technologies and determine which or what combination will lead to a production detector system well suited for use at a high-intensity neutron scattering source

Stripper foil failure modes and cures at the Oak Ridge Spallation Neutron Source

Directory of Open Access Journals (Sweden)

M. A. Plum

2011-03-01

Full Text Available The Oak Ridge Spallation Neutron Source comprises a 1 GeV, 1.5 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H^{0} excited states created during the H^{-} charge-exchange injection into the accumulator ring, the stripper foil is located inside one of the chicane dipoles. This has some interesting consequences that were not fully appreciated until the beam power reached about 840 kW. One consequence was sudden failure of the stripper foil system due to convoy electrons stripped from the incoming H^{-} beam, which circled around to strike the foil bracket and cause bracket failure. Another consequence is that convoy electrons can reflect back up from the electron catcher and strike the foil and bracket. An additional contributor to foil system failure is vacuum breakdown due to the charge developed on the foil by secondary electron emission. In this paper we detail these and other interesting failure mechanisms and describe the improvements we have made to mitigate them.

The Neutron Science TeraGrid Gateway, a TeraGrid Science Gateway to Support the Spallation Neutron Source

International Nuclear Information System (INIS)

Cobb, John W.; Geist, Al; Kohl, James Arthur; Miller, Stephen D; Peterson, Peter F.; Pike, Gregory; Reuter, Michael A; Swain, William; Vazhkudai, Sudharshan S.; Vijayakumar, Nithya N.

2006-01-01

The National Science Foundation's (NSF's) Extensible Terascale Facility (ETF), or TeraGrid (1) is entering its operational phase. An ETF science gateway effort is the Neutron Science TeraGrid Gateway (NSTG.) The Oak Ridge National Laboratory (ORNL) resource provider effort (ORNL-RP) during construction and now in operations is bridging a large scale experimental community and the TeraGrid as a large-scale national cyberinfrastructure. Of particular emphasis is collaboration with the Spallation Neutron Source (SNS) at ORNL. The U.S. Department of Energy's (DOE's) SNS (2) at ORNL will be commissioned in spring of 2006 as the world's brightest source of neutrons. Neutron science users can run experiments, generate datasets, perform data reduction, analysis, visualize results; collaborate with remotes users; and archive long term data in repositories with curation services. The ORNL-RP and the SNS data analysis group have spent 18 months developing and exploring user requirements, including the creation of prototypical services such as facility portal, data, and application execution services. We describe results from these efforts and discuss implications for science gateway creation. Finally, we show incorporation into implementation planning for the NSTG and SNS architectures. The plan is for a primarily portal-based user interaction supported by a service oriented architecture for functional implementation

Challenges and design solutions of the liquid hydrogen circuit at the European Spallation Source

Energy Technology Data Exchange (ETDEWEB)

Gallimore, S.; Nilsson, P.; Sabbagh, P.; Takibayev, A.; Weisend II, J. G. [European Spallation Source ESS AB, SE-22100 Lund (Sweden); Beßler, Y. [Forschungzentrum Jülich, Jülich (Germany); Klaus, M. [Technische Universität Dresden, Dresden (Germany)

2014-01-29

The European Spallation Source (ESS), Lund, Sweden will be a 5MW long-pulse neutron spallation research facility and will enable new opportunities for researchers in the fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics. Neutrons are produced by accelerating a high-energy proton beam into a rotating helium-cooled tungsten target. These neutrons pass through moderators to reduce their energy to an appropriate range (< 5 meV for cold neutrons); two of which will use liquid hydrogen at 17 K as the moderating and cooling medium. There are several technical challenges to overcome in the design of a robust system that will operate under such conditions, not least the 20 kW of deposited heat. These challenges and the associated design solutions will be detailed in this paper.

MEGAPIE spallation target: Design, manufacturing and preliminary tests of the first pro-typical spallation target for future ADS

International Nuclear Information System (INIS)

Latge, Ch.; Laffont, G.; Groeschel, F.; Thomsen, K.; Wagner, W.; Agostini, P.; Dierckx, M.; Fazio, C.; Kirchner, T.; Kurata, Y.; Song, T.; Woloshun, K.

2006-01-01

Partitioning and Transmutation (P and T) techniques could contribute to reduce the radioactive inventory and its associated radiotoxicity. Sub-critical Accelerator Driven Systems (ADS) are potential candidates as dedicated transmutation systems, and thus their development is a relevant R and D topic in Europe. Following a first phase focused on the understanding of the basic principles of ADS (e.g. the programme MUSE), the R and D has been streamlined and focused on practical demonstration key issues. These demonstrations cover high intensity proton accelerators (beam current in the range 1 to 20 mA), spallation targets of high power and their effective coupling with a subcritical core. Presently there is general consensus that up to 1 MW of beam power solid targets are feasible from a heat removal point of view. For higher power levels liquid metal targets are the option of choice because of their higher heat removal capability, higher spallation material density in the volume and lower specific radioactivity, Therefore, a key experiment in the ADS road map, the Megawatt Pilot Experiment (MEGAPIE) (1 MW) was initiated in 1999 in order to design and build a liquid lead-bismuth spallation target, then to operate it into the Swiss spallation neutron facility SINQ at Paul Scherrer Institute (PSI). It has to be equipped to provide the largest possible amount of scientific and technical information without jeopardizing its safe operation. The minimum design service life has been fixed at 1 year (6000 mAh). Whereas the interest of the partner institutes is driven by the development needs of ADS, PSI interest lies also in the potential use of a LM target as a SINQ standard target providing a higher neutron flux than the current solid targets. Calculations of the radial distribution of the undisturbed thermal neutron flux for the LBE target in comparison to the former Zircaloy and current steel-clad solid lead target were done with different nuclear codes; nevertheless

LOS ALAMOS NEUTRON SCIENCE CENTER CONTRIBUTIONS TO THE DEVELOPMENT OF FUTURE POWER REACTORS

Energy Technology Data Exchange (ETDEWEB)

GAVRON, VICTOR I. [Los Alamos National Laboratory; HILL, TONY S. [Los Alamos National Laboratory; PITCHER, ERIC J. [Los Alamos National Laboratory; TOVESSON, FREDERIK K. [Los Alamos National Laboratory

2007-01-09

The Los Alamos Neutron Science Center (LANSCE) is a large spallation neutron complex centered around an 800 MeV high-currently proton accelerator. Existing facilities include a highly-moderated neutron facility (Lujan Center) where neutrons between thermal and keV energies are produced, and the Weapons Neutron Research Center (WNR), where a bare spallation target produces neutrons between 0.1 and several hundred MeV.The LANSCE facility offers a unique capability to provide high precision nuclear data over a large energy region, including that for fast reactor systems. In an ongoing experimental program the fission and capture cross sections are being measured for a number of minor actinides relevant for Generation-IV reactors and transmutation technology. Fission experiments makes use of both the highly moderated spallation neutron spectrum at the Lujan Center, and the unmoderated high energy spectrum at WNR. By combininb measurements at these two facilities the differential fission cross section is measured relative to the {sup 235}U(n,f) standard from subthermal energies up to about 200 MeV. An elaborate data acquisition system is designed to deal with all the different types of background present when spanning 10 energy decades. The first isotope to be measured was {sup 237}Np, and the results were used to improve the current ENDF/B-VII evaluation. Partial results have also been obtained for {sup 240}Pu and {sup 242}Pu, and the final results are expected shortly. Capture cross sections are measured at LANSCE using the Detector for Advanced Neutron Capture Experiments (DANCE). This unique instrument is highly efficient in detecting radiative capture events, and can thus handle radioactive samples of half-lives as low as 100 years. A number of capture cross sections important to fast reaction applications have been measured with DANCE. The first measurement was on {sup 237}Np(n,{gamma}), and the results have been submitted for publication. Other capture

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.

Neutron cross sections for the interpretation of a spallation experiment

International Nuclear Information System (INIS)

Bortignon, P.F.; Mariani, F.; Perini, A.; Sangiust, V.

1994-01-01

An irradiation was carried out in a spallation neutron spectrum at the beam stop of LAMPF (Los Alamos); many activation detectors were used in order to obtain a fluence mapping inside the capsule volume. The cross sections were derived from ENDF B/V Dosimetry File up to 20 MeV and were based on calculations with the code ALICE up to 200 MeV. From 200 to 800 MeV an empirical extrapolation was employed since no data, calculated or measured, were available at the moment. An attempt has been made in this paper to revisit the interpretation of the experiment reconsidering the cross sections in the energy range from 200 to 800 MeV as given by the semiempirical models of Rudstam, Silberger and Tsao and Hufner

Ion source requirements for pulsed spallation neutron sources

International Nuclear Information System (INIS)

Alonso, J.R.

1995-10-01

The neutron scattering community has endorsed the need for a high- power (1 to 5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (sub-microsecond) bursts of cold neutrons, said time structure offering advantages over the continuous flux from a reactor for a large class of experiments. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 KW source in the UK), and call for a high-current (approx. 100 mA peak) H - source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The 1 to 5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty-factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. A workshop held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H - source technologies, and identified necessary R ampersand D efforts to bridge the gap

Parametric study of emerging high power accelerator applications using Accelerator Systems Model (ASM)

International Nuclear Information System (INIS)

Berwald, D.H.; Mendelsohn, S.S.; Myers, T.J.; Paulson, C.C.; Peacock, M.A.; Piaszczyk, CM.; Rathke, J.W.; Piechowiak, E.M.

1996-01-01

Emerging applications for high power rf linacs include fusion materials testing, generation of intense spallation neutrons for neutron physics and materials studies, production of nuclear materials and destruction of nuclear waste. Each requires the selection of an optimal configuration and operating parameters for its accelerator, rf power system and other supporting subsystems. Because of the high cost associated with these facilities, economic considerations become paramount, dictating a full evaluation of the electrical and rf performance, system reliability/availability, and capital, operating, and life cycle costs. The Accelerator Systems Model (ASM), expanded and modified by Northrop Grumman during 1993-96, provides a unique capability for detailed layout and evaluation of a wide variety of normal and superconducting accelerator and rf power configurations. This paper will discuss the current capabilities of ASM, including the available models and data base, and types of trade studies that can be performed for the above applications. (author)

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

Cumulative beam break-up study of the spallation neutron source superconducting linac

CERN Document Server

Jeon, D; Krafft, G A; Yunn, B; Sundelin, R; Delayen, J; Kim, S; Doleans, M

2002-01-01

Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H sup - beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H sup - beam and the HOM frequency spread resulting from manufacturing tolerances. As little as +-0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of +-0.1 MHz HOM is small, and hence conservative compared with measured values of sigma=0.00109(f sub H sub O sub M -f sub 0)/f sub 0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat lo...

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

The MEGAwatt PIlot Experiment (MEGAPIE) project was started in 2000 to design, build and operate a liquid metal spallation neutron target at the power level of 1 MW. The project is an important step in the roadmap towards the demonstration of the Accelerator-Driven System (ADS) concept and for high power molten metal targets in general. In an ADS the spallation target is placed inside a sub-critical reactor core. The role of the spallation target is to provide the extra neutrons needed by the sub-critical core to keep the reactor working. Since an ADS is a fast neutron system, there is no moderation and the spallation neutron spectrum is therefore a typical fast spectrum. For a sub-critical core with k{sub eff} = 0.95, a strong neutron source is needed, and in the roadmap an accelerator current higher than 10 mA is indicated as baseline parameter for the experimental ADS. The choice of the accelerator current and energy depends primarily on the number of neutrons that need to be generated, and that are used to drive the reactor. With the 590 MeV cyclotron delivering a continuous beam on target with a current up to 1.8 mA, SINQ was chosen for the MEGAPIE experiment as the most powerful spallation neutron source in the world, with a proton beam power on target that can reach 1 MW. Up to MEGAPIE all SINQ targets were based on a bundle of heavy material rods (full zircaloy, steel rods filled with Pb, zircaloy rods filled with Pb) cooled by a flow of heavy water. For the MEGAPIE target a loop of about 82 litres of lead-bismuth eutectic (LBE) circulates enclosed by a steel structure. The target is about 5 m long and the LBE is made circulating by means of a main electromagnetic pump. The neutronic performance was deduced from flux measurements done at different positions and distances from the spallation target, because the neutron yield (number of neutrons per incoming proton) cannot be directly measured. The presence of the heavy water moderator in the SINQ facility

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

Spallation reactions and energy deposition in heavy target materials comparison of measurements and MC-calculations

International Nuclear Information System (INIS)

Filges, D.; Enke, M.; Galin, J.

2001-01-01

A renascence of interest for energetic proton induced production of neutrons originates recently by the inception of new projects for target stations of intense spallation neutron sources (like the planned European Spallation Source ESS), accelerator-driven nuclear reactors, nuclear waste transmutation and also the application for radioactive beams. Here we verify the predictive power of transport codes currently on the market by confronting observables and quantities of interest with an exhaustive matrix of benchmark data essentially coming from two experiments being performed at the Cooler Synchrotron COSY at Juelich. Program packages like HERMES, LCS or MCNPX master the prevision of reaction cross sections, hadronic interaction lengths, averaged neutron multiplicities and neutron multiplicity distributions in thick and thin(!) targets for a wide spectrum of incident proton energies, geometrical shapes and materials of the target. While also the observables related to the energy deposition in thick targets are in a good agreement with the model predictions, the production cross section measurements however for light charged particles on thin targets point out that problems exist within these models. (author)

Superconducting Prototype Cavities for the Spallation Neutron Source (SNS) Project

International Nuclear Information System (INIS)

Ciovati, G.; Kneisel, P.; Brawley, J.; Bundy, R.; Campisi, I.; Davis, K.; Macha, K.; Machie, D.; Mammosser, J.; Morgan, S.; Sundelin, R.; Turlington, L.; Wilson, K.; Doleans, M.; Kim, S.H.; Barni, D.; Pagani, C.; Pierini, P.; Matsumoto, K.; Mitchell, R.; Schrage, D.; Parodi, R.; Sekutowicz, J.; Ylae-Oijala, P.

2001-01-01

The Spallation Neutron Source project includes a superconducting linac section in the energy range from 192 MeV to 1000 MeV, operating at a frequency of 805 MHz at 2.1 K. For this energy range two types of cavities are needed with geometrical beta - values of beta= 0.61 and beta= 0.81. An aggressive cavity prototyping program is being pursued at Jlab, which calls for fabricating and testing of four beta= 0.61 cavities and two beta= 0.81 cavities. Both types consist of six cells made from high purity niobium and feature one HOM coupler on each beam pipe and a port for a high power coaxial input coupler. Three of the four beta= 0.61 cavities will be used for a cryomodule test in early 2002. At this time four medium beta cavities and one high beta cavity have been completed at JLab. The first tests on the beta=0.61 cavity and the beta= 0.81 exceeded the design values for gradient and Q - value: E acc = 1 0.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.61 and E acc = 12.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.81. One of the medium beta cavities has been equipped with an integrated helium vessel and measurements of the static and dynamic Lorentz force detuning will be done and compared to the ''bare'' cavities. In addition two single cell cavities have been fabricated, equipped with welded-on HOM couplers. They are being used to evaluate the HOM couplers with respect to multipacting, fundamental mode rejection and HOM damping as far as possible in a single cell. This paper will describe the cavity design with respect to electrical and mechanical features, the fabrication efforts and the results obtained with the different cavities existing at the time of this workshop

SINQ - a continuous spallation neutron source (an approach to 1 MWatt of beam power)

International Nuclear Information System (INIS)

Fischer, W.E.

1995-01-01

In this status report we describe the continuous spallation source at PSI, which will come into operation in fall 1996. We present the present state of the construction work and review the expected performance of the source. (author) 10 figs., 2 tabs., refs

SINQ - a continuous spallation neutron source (an approach to 1 MWatt of beam power)

Energy Technology Data Exchange (ETDEWEB)

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

1995-11-01

In this status report we describe the continuous spallation source at PSI, which will come into operation in fall 1996. We present the present state of the construction work and review the expected performance of the source. (author) 10 figs., 2 tabs., refs.

Self-powered neutron detector of high sensitivity

International Nuclear Information System (INIS)

Brixy, H.; Spillekothen, H.G.; Benninghofen, G.; Serafin, N.

1983-01-01

A self-powered neutron detector is proposed, consisting of three concentrically arranged electrically conducting tubes; where the central one forms the emitter and the inner and outer ones form the collector and where the tubes are electrically insulated from each other by insulating material. The emitter consists of a material with a high absorption cross-section for thermal neutrons, particularly of gadolinium, and is provided with an auxiliary emitter layer on the inside or the outside. With suitable dimensions and material, the auxiliary emitter layer increases the yield of electrons. (orig./HP) [de

Neutron cross-sections above 20 MeV for design and modeling of ...

Indian Academy of Sciences (India)

One of the outstanding new developments in the field of partitioning and transmutation (P&T) concerns accelerator-driven systems (ADS) which consist of a combination of a high-power, high-energy accelerator, a spallation target for neutron production and a sub-critical reactor core. The development of the commercial ...

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

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

Flux gain for a next-generation neutron reflectometer resulting from improved supermirror performance

CERN Document Server

Rehm, C

2002-01-01

Next-generation spallation neutron source facilities will offer instruments with unprecedented capabilities through simultaneous enhancement of source power and usage of advanced optical components. The Spallation Neutron Source (SNS), already under construction at Oak Ridge National Laboratory and scheduled to be completed by 2006, will provide greater than an order of magnitude more effective source flux than current state-of-the-art facilities, including the most advanced research reactors. An additional order of magnitude gain is expected through the use of new optical devices and instrumentation concepts. Many instrument designs require supermirror neutron guides with very high critical angles for total reflection. In this contribution, we will discuss how the performance of a modern neutron-scattering instrument depends on the efficiency of these supermirrors. We summarize current limitations of supermirror coatings and outline ideas for enhancing their performance, particularly for improving the reflec...

Ion source requirements for pulsed spallation neutron sources

International Nuclear Information System (INIS)

Alonso, J.R.

1996-01-01

The neutron scattering community has endorsed the need for a high-power (1 to 5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (sub-microsecond) bursts of cold neutrons, said time structure offering advantages over the continuous flux from a reactor for a large class of experiments. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 kW source in the UK), and call for a high-current (approx. 100 mA peak) H - source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The 1 to 5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty-factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. A workshop held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H - source technologies, and identified necessary R ampersand D efforts to bridge the gap. copyright 1996 American Institute of Physics

Commissioning of cryogenic system for China Spallation Neutron Source

Science.gov (United States)

Ye, Bin; He, Chongchao; Li, Na; Ding, Meiying; Wang, Yaqiong; Yu, Zhang; He, Kun

2017-12-01

China Spallation Neutron Source(CSNS) cryogenic system provides supercritical cryogenic hydrogen to neutron moderators, including a helium refrigerator, hydrogen loop and hydrogen safety equipment. The helium refrigerator is provided by Linde with cooling capacity of 2200 W at 20 K. Hydrogen loop system mainly includes cryogenic hydrogen pipes, hydrogen circulator cold-box and accumulator cold-box. Cryogenic hydrogen pump, ortho-para convertor, helium-hydrogen heat-exchanger, hydrogen heater and accumulator are integrated in hydrogen circulation cold-box, and accumulator cold-box. Hydrogen safety equipment includes safety valves, rupture disk, hydrogen sensor, flame detector and other equipment to ensure that cryogenic system in dangerous situations will go down, vents, or takes other measures. The cryogenic system commissioning work includes four steps. First, in order to test the refrigerating capacity of refrigerator, when acceptance testing, refrigerator internal heater was used as thermal load. Second, using simulation load as heat load of moderator, hydrogen loop use helium instead of hydrogen, and cooled down to 20 K, then re-warming and test the leak detection of hydrogen loop system. Third, base on the step 2, using hydrogen as working medium, and optimized the control logic. Forth, cryogenic system with the moderators joint commissioning. Now, cryogenic system is connected with the moderators, and the forth step will be carried out in the near future.

The Design and Performance of the Spallation Neutron Source Low-Level RF Control System

CERN Document Server

Champion, M; Kasemir, K; Ma, H; Piller, C

2004-01-01

The Spallation Neutron Source linear accelerator low-level RF control system has been developed within a collaboration of Lawrence Berkeley, Los Alamos, and Oak Ridge national laboratories. Three distinct generations of the system, described in a previous publication [1], have been used to support beam commissioning at Oak Ridge. The third generation system went into production in early 2004, with installation in the coupled-cavity and superconducting linacs to span the remainder of the year. The final design of this system will be presented along with results of performance measurements.

Spallation-based science and technology and associated nuclear data requirements

International Nuclear Information System (INIS)

Bowman, C.D.; Lisowski, P.W.; Arthur, E.D.

1990-01-01

Rapid advances in accelerator technology in recent years promise average proton beam currents as high as 250 mA with energies greater than one GeV. Such an accelerator could produce very high intensities of neutrons and other nuclear particles thus opening up new areas of science and technology. An example is the efficient burning of transuranic and fission product waste. With such a spallation-burner it appears that high-level waste might be converted to low-level waste on a time scale comparable to the human lifespan at a reasonable additional cost for electric power generation. The emphasis of this paper is on the design of a high power proton target for neutron production, on the nuclear data needed to operate this target safely and effectively, and on data requirements for transmutation. It is suggested that a pilot facility consisting of a 1.6 GeV accelerator and target operating at 25 ma is the next major step in developing this technology. Bursts of protons near the terawatt level might also be generated using such an accelerator with a proton accumulator ring. Research prospects based on such proton bursts are briefly described. The status of established nuclear data needs and of accelerator-based sources for nuclear data measurements is reviewed. (author)

A Family of L-band SRF Cavities for High Power Proton Driver Applications

International Nuclear Information System (INIS)

Rimmer, Robert; Marhauser, Frank

2009-01-01

Recent global interest in high duty factor or CW superconducting linacs with high average beam power highlights the need for robust and reliable SRF structures capable of delivering high average RF power to the beam with moderate HOM damping, low interception of halo and good efficiency. Potential applications include proton or H- drivers for spallation neutron sources, neutrino physics, waste transmutation, subcritical reactors, and high-intensity high-energy physics experiments. We describe a family of SRF cavities with a range of Betas capable of transporting beam currents in excess of 10 mA CW with large irises for minimal interception of halo and HOM and power couplers capable of supporting high average power operation. Goals include an efficient cell shape, high packing factor for efficient real-estate gradient and strong HOM damping to ensure stable beam operation,

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)

Development opportunities for small and medium scale accelerator driven neutron sources. Proceedings of a technical meeting

International Nuclear Information System (INIS)

2005-02-01

Neutron applications in the life sciences will be a rapidly growing research area in the near future, as neutrons can provide unique information on the reaction dynamics of complex biomolecular systems, complementing other analytical techniques such as electron microscopy, X rays and nuclear magnetic resonance. Small and medium power spallation neutron sources will become more important, as many small neutron producing research reactors are being phased out. Recent developments in accelerator technology have made it possible to produce useful neutron fluxes at accelerator facilities suitable for universities and industrial laboratories. In addition to basic research these alternative neutron sources will be important for educational and training purposes. In a wider perspective this technology should make it possible to introduce neutron research and applications to industrial and national research centres in IAEA Member States that are unable to afford a high energy spallation neutron source and have no access to a research reactor

Strong neutron sources - How to cope with weapon material production capabilities of fusion and spallation neutron sources?

International Nuclear Information System (INIS)

Englert, M.; Franceschini, G.; Liebert, W.

2013-01-01

In this article we investigate the potential and relevance for weapon material production in future fusion power plants and spallation neutron sources (SNS) and sketch what should be done to strengthen these technologies against a non-peaceful use. It is shown that future commercial fusion reactors may have military implications: first, they provide an easy source of tritium for weapons, an element that does not fall under safeguards and for which diversion from a plant could probably not be detected even if some tritium accountancy is implemented. Secondly, large fusion reactors - even if not designed for fissile material breeding - could easily produce several hundred kg Pu per year with high weapon quality and very low source material requirements. If fusion-only reactors will prevail over fission-fusion hybrids in the commercialization phase of fusion technology, the safeguard challenge will be more of a legal than of a technical nature. In pure fusion reactors (and in most SNS) there should be no nuclear material present at any time by design. The presence of undeclared nuclear material would indicate a military use of the plant. This fact offers a clear-cut detection criterion for a covert use of a declared facility. Another important point is that tritium does not fall under the definition of 'nuclear material', so a pure fusion reactor or a SNS that do not use nuclear materials are not directly falling under any international non-proliferation treaty requirements. Non-proliferation treaties have to be amended to take into account that fact. (A.C.)

Geometric optimization of spallation targets for the MYRRHA reactor using MCNPX simulations

Energy Technology Data Exchange (ETDEWEB)

Rebello Junior, Andre Luiz P.; Martinez, Aquilino S.; Golcalves, Alessandro C., E-mail: junior.rebello@poli.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Nuclear

2013-07-01

The present work aims to evaluate the behavior of neutron multiplicity in a spallation target using MCNPX simulations, focusing on its application in the MYRRHA reactor. It was studied the two types of spallation target proposed for the MYRRHA project, windowless and windows target, in order to compare them and nd saturation boundaries. Some saturation boundaries were found and the windowless target proved to be as viable as the windows one. Each one produced nearly the same number of neutrons per incident proton. Using the concept of neutron cost, it was also observed that the optimum conditions on neutron production occur at about 1GeV, for both target designs. (author)

Geometric optimization of spallation targets for the MYRRHA reactor using MCNPX simulations

International Nuclear Information System (INIS)

Rebello Junior, Andre Luiz P.; Martinez, Aquilino S.; Golcalves, Alessandro C.

2013-01-01

The present work aims to evaluate the behavior of neutron multiplicity in a spallation target using MCNPX simulations, focusing on its application in the MYRRHA reactor. It was studied the two types of spallation target proposed for the MYRRHA project, windowless and windows target, in order to compare them and nd saturation boundaries. Some saturation boundaries were found and the windowless target proved to be as viable as the windows one. Each one produced nearly the same number of neutrons per incident proton. Using the concept of neutron cost, it was also observed that the optimum conditions on neutron production occur at about 1GeV, for both target designs. (author)

GEANT4 simulations of the n{sub T}OF spallation source and their benchmarking

Energy Technology Data Exchange (ETDEWEB)

Lo Meo, S. [Research Centre ' ' Ezio Clementel' ' , ENEA, Bologna (Italy); Section of Bologna, INFN, Bologna (Italy); Cortes-Giraldo, M.A.; Lerendegui-Marco, J.; Guerrero, C.; Quesada, J.M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); Massimi, C.; Vannini, G. [Section of Bologna, INFN, Bologna (Italy); University of Bologna, Physics and Astronomy Dept. ' ' Alma Mater Studiorum' ' , Bologna (Italy); Barbagallo, M.; Colonna, N. [INFN, Section of Bari, Bari (Italy); Mancusi, D. [CEA-Saclay, DEN, DM2S, SERMA, LTSD, Gif-sur-Yvette CEDEX (France); Mingrone, F. [Section of Bologna, INFN, Bologna (Italy); Sabate-Gilarte, M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Vlachoudis, V. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Collaboration: The n_TOF Collaboration

2015-12-15

Neutron production and transport in the spallation target of the n{sub T}OF facility at CERN has been simulated with GEANT4. The results obtained with different models of high-energy nucleon-nucleus interaction have been compared with the measured characteristics of the neutron beam, in particular the flux and its dependence on neutron energy, measured in the first experimental area. The best agreement at present, within 20% for the absolute value of the flux, and within few percent for the energy dependence in the whole energy range from thermal to 1 GeV, is obtained with the INCL++ model coupled with the GEANT4 native de-excitation model. All other available models overestimate by a larger factor, of up to 70%, the n{sub T}OF neutron flux. The simulations are also able to accurately reproduce the neutron beam energy resolution function, which is essentially determined by the moderation time inside the target/moderator assembly. The results here reported provide confidence on the use of GEANT4 for simulations of spallation neutron sources. (orig.)

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

Recent developments on micrometric fission chambers for high neutron fluxes

International Nuclear Information System (INIS)

Letourneau, A.; Bringer, O.; Dupont, E.; Marie, F.; Panebianco, S.; Toussaint, J. C.; Veyssiere, C.; Chabod, S.; Breaud, S.; Oriol, L.

2009-01-01

With the development of innovative nuclear systems and new generation neutron sources, the nuclear instrumentation should be adapted. Since several years, we developed microscopic fission chambers to study the transmutation of minor actinides in high thermal-neutron fluxes. The recent developments done to fulfill the drastic conditions of irradiations are described in this paper together with the feedback from the measurements. Two installations were used: the HFR of the ILL for its highest thermal neutron flux of the world and the MEGAPIE target which was the first 1 MW liquid Pb-Bi spallation target in the world. (authors)

Recent developments on micrometric fission chambers for high neutron fluxes

Energy Technology Data Exchange (ETDEWEB)

Letourneau, A. [Irfu, Service de Physique Nucleaire, CEA-Saclay, 91191 Gif-sur-Yvette (France); Bringer, O.; Dupont, E.; Marie, F.; Panebianco, S.; Toussaint, J. C.; Veyssiere, C. [Irfu, CEA-Saclay, 91191 Gif-sur-Yvette (France); Chabod, S. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3 (France); Breaud, S.; Oriol, L. [DEN/DER/SPEX, CEA-Cadarache, Saint-Paul-lez-Durances (France)

2009-07-01

With the development of innovative nuclear systems and new generation neutron sources, the nuclear instrumentation should be adapted. Since several years, we developed microscopic fission chambers to study the transmutation of minor actinides in high thermal-neutron fluxes. The recent developments done to fulfill the drastic conditions of irradiations are described in this paper together with the feedback from the measurements. Two installations were used: the HFR of the ILL for its highest thermal neutron flux of the world and the MEGAPIE target which was the first 1 MW liquid Pb-Bi spallation target in the world. (authors)

Accelerator driven systems (ADS): A principal neutronics and transmutation potential

International Nuclear Information System (INIS)

Slessarev, I.

1997-01-01

An accelerator-based system using a beam of high energy protons to produce supplementary neutrons as a result of spallation processes in a target is investigated. The spallation neutrons are successively used to feed a subcritical blanket where they create a neutron surplus available for incineration of those long-lived toxic nuclei which require neutrons (long-lived fission products and minor actinides), and enhance the deterministic safety features for reactivity-type of accidents

Complementarity of long pulse and short pulse spallation sources

Energy Technology Data Exchange (ETDEWEB)

Mezei, F [Hahn-Meitner-Institut Berlin GmbH (Germany)

1995-11-01

The complementarity of short pulse spallation sources (SPSS) and steady state (CW) reactors is a widely accepted concept. SPSS and long pulse spallation sources (LPSS) are complementary in two ways: (a) in their performance in neutron scattering experiments LPSS closely emulate CW reactors. In this respect two facets of the time-of-flight (TOF) monochromator method adequate for LPSS will be discussed: the superiority of the TOF approach to the crystal monochromator method in high resolution powder diffraction, and the novel technique of repetition rate multiplication in TOF spectroscopy, (b) LPSS combined with adequate chopper systems can also emulate SPSS in a number of applications. It will be shown that the LPSS method of producing short neutron pulses is more efficient for cold and thermal neutrons (below an energy of about 100 MeV), while SPSS is the more favourable approach for hot, epithermal neutrons, i.e. in the slowing down regime in contrast to the moderated regime. These two aspects of complementarity of LPSS and SPSS lead to the conclusions that for about 75% of the spectrum of neutron scattering experiments as known of today the LPSS approach is the most advantageous one with a feasible neutron intensity exceeding that available at ILL by a factor of about 30, while for the remaining 25% of applications the SPSS technique is superior with a well-known potential of a similar gain over present day performances. (author) 7 figs., 6 refs.

Complementarity of long pulse and short pulse spallation sources

International Nuclear Information System (INIS)

Mezei, F.

1995-01-01

The complementarity of short pulse spallation sources (SPSS) and steady state (CW) reactors is a widely accepted concept. SPSS and long pulse spallation sources (LPSS) are complementary in two ways: a) in their performance in neutron scattering experiments LPSS closely emulate CW reactors. In this respect two facets of the time-of-flight (TOF) monochromator method adequate for LPSS will be discussed: the superiority of the TOF approach to the crystal monochromator method in high resolution powder diffraction, and the novel technique of repetition rate multiplication in TOF spectroscopy, b) LPSS combined with adequate chopper systems can also emulate SPSS in a number of applications. It will be shown that the LPSS method of producing short neutron pulses is more efficient for cold and thermal neutrons (below an energy of about 100 MeV), while SPSS is the more favourable approach for hot, epithermal neutrons, i.e. in the slowing down regime in contrast to the moderated regime. These two aspects of complementarity of LPSS and SPSS lead to the conclusions that for about 75% of the spectrum of neutron scattering experiments as known of today the LPSS approach is the most advantageous one with a feasible neutron intensity exceeding that available at ILL by a factor of about 30, while for the remaining 25% of applications the SPSS technique is superior with a well-known potential of a similar gain over present day performances. (author) 7 figs., 6 refs

Magnetism and magnetic materials probed with neutron scattering

International Nuclear Information System (INIS)

Velthuis, S.G.E. te; Pappas, C.

2014-01-01

Neutron scattering techniques are becoming increasingly accessible to a broader range of scientific communities, in part due to the onset of next-generation, high-power spallation sources, high-performance, sophisticated instruments and data analysis tools. These technical advances also advantageously impact research into magnetism and magnetic materials, where neutrons play a major role. In this Current Perspective series, the achievements and future prospects of elastic and inelastic neutron scattering, polarized neutron reflectometry, small angle neutron scattering, and neutron imaging, are highlighted as they apply to research into magnetic frustration, superconductivity and magnetism at the nanoscale. - Highlights: • Introduction to Current Perspective series titled Magnetism and Magnetic Materials probed with Neutron Scattering. • Elastic and inelastic neutron scattering in systems with magnetic frustration and superconductivity. • Small angle neutron scattering and polarized neutron reflectometry in studying magnetism at the nanoscale. • Imaging of magnetic fields and domains

Magnetism and magnetic materials probed with neutron scattering

Energy Technology Data Exchange (ETDEWEB)

Velthuis, S.G.E. te, E-mail: tevelthuis@anl.gov [Materials Science Division, Argonne National Laboratory, 9700 S Cass Ave, Argonne, IL 60439 (United States); Pappas, C. [Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, NL-2629JB Delft (Netherlands)

2014-01-15

Neutron scattering techniques are becoming increasingly accessible to a broader range of scientific communities, in part due to the onset of next-generation, high-power spallation sources, high-performance, sophisticated instruments and data analysis tools. These technical advances also advantageously impact research into magnetism and magnetic materials, where neutrons play a major role. In this Current Perspective series, the achievements and future prospects of elastic and inelastic neutron scattering, polarized neutron reflectometry, small angle neutron scattering, and neutron imaging, are highlighted as they apply to research into magnetic frustration, superconductivity and magnetism at the nanoscale. - Highlights: • Introduction to Current Perspective series titled Magnetism and Magnetic Materials probed with Neutron Scattering. • Elastic and inelastic neutron scattering in systems with magnetic frustration and superconductivity. • Small angle neutron scattering and polarized neutron reflectometry in studying magnetism at the nanoscale. • Imaging of magnetic fields and domains.

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 ...

Basic aspects of spallation radiation damage to materials

Energy Technology Data Exchange (ETDEWEB)

Wechsler, M.S.; Lin, C. [North Carolina State Univ., Raleigh, NC (United States); Sommer, W.F. [Los Alamos National Laboratory, NM (United States)

1995-10-01

The nature of radiation effects, as learned from investigations using reactor neutron irradiations, is reviewed, and its relevance to spallation radiation damage to materials in accelerator-driven neutron sources is discussed. Property changes upon irradiation are due to (1) displaced atoms, producing vacancy and interstitial defect clusters, which cause radiation hardening and embrittlement; (2) helium production, the helium then forming bubbles, which engenders high-temperature grain-boundary fracture; and (3) transmutations, which means that impurity concentrations are introduced. Methods for analyzing displacement production are related, and recent calculations of displacement cross sections using SPECTER and LAHET are described, with special reference to tungsten, a major candidate for a target material in accelerator-driven neutron systems.

The second workshop of neutron science research program

Energy Technology Data Exchange (ETDEWEB)

Yasuda, Hideshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tone, Tatsuzo [eds.

1997-11-01

The Japan Atomic Energy Research Institute(JAERI) has been proposing the Neutron Science Research Program to explore a broad range of basic research and the nuclear technology including actinide transmutation with use of powerful spallation neutron sources. For this purpose, the JAERI is conducting the research and development of an intense proton linac, the development of targets, as well as the conceptual design study of experimental facilities required for applications of spallation neutrons and secondary particle beams. The Special Task Force for Neutron Science Initiative was established in May 1996 to promote aggressively and systematically the Neutron Science Research Program. The second workshop on neutron science research program was held at the JAERI Tokai Research Establishment on 13 and 14 March 1997 for the purpose of discussing the results obtained since the first workshop in March 1996. The 27 of the presented papers are indexed individually. (J.P.N.)

Simulation of a suite of generic long-pulse neutron instruments to optimize the time structure of the European Spallation Source.

Science.gov (United States)

Lefmann, Kim; Klenø, Kaspar H; Birk, Jonas Okkels; Hansen, Britt R; Holm, Sonja L; Knudsen, Erik; Lieutenant, Klaus; von Moos, Lars; Sales, Morten; Willendrup, Peter K; Andersen, Ken H

2013-05-01

We here describe the result of simulations of 15 generic neutron instruments for the long-pulsed European Spallation Source. All instruments have been simulated for 20 different settings of the source time structure, corresponding to pulse lengths between 1 ms and 2 ms; and repetition frequencies between 10 Hz and 25 Hz. The relative change in performance with time structure is given for each instrument, and an unweighted average is calculated. The performance of the instrument suite is proportional to (a) the peak flux and (b) the duty cycle to a power of approximately 0.3. This information is an important input to determining the best accelerator parameters. In addition, we find that in our simple guide systems, most neutrons reaching the sample originate from the central 3-5 cm of the moderator. This result can be used as an input in later optimization of the moderator design. We discuss the relevance and validity of defining a single figure-of-merit for a full facility and compare with evaluations of the individual instrument classes.

Simulation of a suite of generic long-pulse neutron instruments to optimize the time structure of the European Spallation Source

Energy Technology Data Exchange (ETDEWEB)

Lefmann, Kim; Kleno, Kaspar H.; Holm, Sonja L.; Sales, Morten [Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O (Denmark); Danish Workpackage for the ESS Design Update Phase, Universitetsparken 5, 2100 Copenhagen O (Denmark); Birk, Jonas Okkels [Nanoscience and eScience Centers, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O (Denmark); Danish Workpackage for the ESS Design Update Phase, Universitetsparken 5, 2100 Copenhagen O (Denmark); Laboratory for Quantum Magnetism, Ecole Polytecnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Hansen, Britt R.; Knudsen, Erik; Willendrup, Peter K. [Institute of Physics, Technical University of Denmark, 2800 Lyngby (Denmark); Danish Workpackage for the ESS Design Update Phase, 2800 Lyngby (Denmark); Lieutenant, Klaus [Institute for Energy Technology, Instituttveien 18, 2007 Kjeller (Norway); Helmholtz Center for Energy and Materials, Hahn-Meitner Platz, 14109 Berlin (Germany); German Work Package for the ESS Design Update, Hahn-Meitner Platz, 14109 Berlin (Germany); Moos, Lars von [Department of Energy Conversion and Storage, Technical University of Denmark, 4000 Roskilde (Denmark); Danish Workpackage for the ESS Design Update Phase, 2800 Lyngby (Denmark); Institute for Energy Conversion, Technical University of Denmark, 4000 Roskilde (Denmark); Andersen, Ken H. [European Spallation Source ESS AB, 22100 Lund (Sweden)

2013-05-15

We here describe the result of simulations of 15 generic neutron instruments for the long-pulsed European Spallation Source. All instruments have been simulated for 20 different settings of the source time structure, corresponding to pulse lengths between 1 ms and 2 ms; and repetition frequencies between 10 Hz and 25 Hz. The relative change in performance with time structure is given for each instrument, and an unweighted average is calculated. The performance of the instrument suite is proportional to (a) the peak flux and (b) the duty cycle to a power of approximately 0.3. This information is an important input to determining the best accelerator parameters. In addition, we find that in our simple guide systems, most neutrons reaching the sample originate from the central 3-5 cm of the moderator. This result can be used as an input in later optimization of the moderator design. We discuss the relevance and validity of defining a single figure-of-merit for a full facility and compare with evaluations of the individual instrument classes.

Simulation of a suite of generic long-pulse neutron instruments to optimize the time structure of the European Spallation Source

International Nuclear Information System (INIS)

Lefmann, Kim; Klenø, Kaspar H.; Holm, Sonja L.; Sales, Morten; Birk, Jonas Okkels; Hansen, Britt R.; Knudsen, Erik; Willendrup, Peter K.; Lieutenant, Klaus; Moos, Lars von; Andersen, Ken H.

2013-01-01

We here describe the result of simulations of 15 generic neutron instruments for the long-pulsed European Spallation Source. All instruments have been simulated for 20 different settings of the source time structure, corresponding to pulse lengths between 1 ms and 2 ms; and repetition frequencies between 10 Hz and 25 Hz. The relative change in performance with time structure is given for each instrument, and an unweighted average is calculated. The performance of the instrument suite is proportional to (a) the peak flux and (b) the duty cycle to a power of approximately 0.3. This information is an important input to determining the best accelerator parameters. In addition, we find that in our simple guide systems, most neutrons reaching the sample originate from the central 3–5 cm of the moderator. This result can be used as an input in later optimization of the moderator design. We discuss the relevance and validity of defining a single figure-of-merit for a full facility and compare with evaluations of the individual instrument classes.

Combined Neutron Center for European Research and Technology

International Nuclear Information System (INIS)

Lagniel, Jean-Michel

2002-01-01

High-power proton linacs are needed as driver for several applications, namely transmutation of nuclear waste using Accelerator Driven Systems (ADS), spallation neutron sources (ESS in Europe) and other fields of basic and applied research (next generation of radioactive ion beam facilities, neutrino factories, muon colliders, irradiation facilities for material testing...). The possible synergies among these projects will be pointed out and the feasibility study of high-power proton linac used as driver of a multi-user facility (CONCERT) will be presented. There was excellent scientific, technical and economic reasons to study a Combined Neutron Center for European Research and Technology (CONCERT) based on a high-power proton accelerator. Such an installation would serve condensed matter studies by spallation neutron scattering, a technological irradiation tool and R and D facility for an hybrid reactor demonstrator, a radioactive ion beam facility for nuclear physics, R and D developments for a muon/neutrino facility. The installation could therefore constitute a European center of excellence in the field of neutronics where a large number of scientific and technical executives could be trained. The CONCERT Project Team has performed the feasibility study of such a multi-user facility with: - a review of the beam needs for the different applications, - an analyze of their compatibility, - the definition of the scope of a site-independent project, - a selection of the most appropriate options regarding scientific, technical, financial, organizational and administrative aspects, - an estimation of the costs for construction, operation and the needs in manpower. The conceptual design report [17] is sufficiently detailed to minimize contingencies on those parts of the project having a large potential impact in terms of performances, costs or delays. (author)

HYSPEC: A crystal time-of-flight hybrid spectrometer for the spallation neutron source with polarization capabilities

International Nuclear Information System (INIS)

Shapiro, S.M.; Zaliznyak, I.A.; Passell, L.; Ghosh, V.J.; Leonhardt, W.J.; Hagen, M.E.

2006-01-01

The hybrid spectrometer (HYSPEC) is a unique direct geometry inelastic scattering instrument under construction at the spallation neutron source (SNS). It combines the intensity enhancement features of focusing Bragg crystals with time-of-flight energy analysis. It will be located at beam-line 14B, which views a coupled liquid hydrogen moderator. A neutron beam from the moderator will travel along a curved guide, through a Fermi chopper and will then be focused onto a sample in an external building, 39 m from the source. In this configuration the intensity at the sample position is more than an order of magnitude larger than for other planned inelastic instrument. A movable detector bank 4.5 m from the sample will cover an angular range of 60 deg. in the horizontal plane and 15 deg. in the vertical direction. An important feature of HYSPEC is the ability to do neutron polarization analysis experiments. A Heusler crystal, which polarizes the neutron beam, can be used as the focusing crystal and a series of bender analyzers will analyze the polarization of the scattered beam

Spallation-based science and technology and associated nuclear data requirements

International Nuclear Information System (INIS)

Bowman, C.D.; Lisowski, P.W.; Arthur, E.D.

1990-01-01

Rapid advances in accelerator technology in recent years promise average proton beam currents as high as 250 mA with energies greater than one GeV. Such an accelerator could produce very high intensities of neutrons and other nuclear particles thus opening up new areas of science and technology. An example is the efficient burning of transuranic and fission product waste. With such a spallation-burner it appears that high-level waste might be converted to low-level waste on a time scale comparable to the human lifespan at a reasonable additional cost for electric power generation. The emphasis of this paper is on the design of a high power proton target for neutron production, on the nuclear data needed to operate this target safely and effectively, and on data requirements for transmutation. It is suggested that a pilot facility consisting of a 1.6 GeV accelerator and target operating at 25 ma is the next major step in developing this technology. Bursts of protons near the terawatt level might also be generated using such an accelerator with a proton accumulator ring. Research prospects based on such proton bursts are briefly described. The status of established nuclear data needs and of accelerator-based sources for nuclear data measurements is reviewed. 6 refs., 8 figs., 2 tabs

High uniformity magnetic coil for search of neutron electric dipole moment