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Sample records for spallation source accelerator

  1. Accelerators for Driving Intense spallation Neutron Sources

    International Nuclear Information System (INIS)

    Gilad, P.

    2002-01-01

    A worldwide trend to replace aging research reactors with accelerator driven neutron sources is currently underway. The ''SARAF'' program at Soreq NRC is a notable example. Setting the background to this trend, a review of the history of accelerator based spallation neutron sources is presented. We follow the evolution of ideas and projects for intense spallation neutron sources. The survey is mainly focused on the properties of the accelerators chosen as drivers throughout the evolution of spallation neutron sources. Since the late 1940s, high-energy proton and deuteron accelerators were developed in view of producing intense neutron sources for various applications related to the nuclear industry, i.e. breeding fissile isotopes, driving nuclear reactors using alternative fuels (like the 'Energy Amplifier') and nuclear waste incineration. However, these projects never progressed beyond the R and D stage. In recent years there is a trend to replace aging reactor-based strong cw neutron sources by pulsed intense spallation sources. Their main applications are in the fields of physics research, material sciences, biology and medicine. Prominent examples of successful projects are ISIS at RAL in Great Britain and SINQ at PSI in Switzerland. Other successful projects are noted in Japan and the US. The clear success of these spallation sources prompted the development of a new generation of more intense spallation neutron sources, notably in Europe (ESS), US (SNS) and Japan (JAERI). Generally, the pulsed spallation neutron sources are based on high-energy proton accelerators. Initially, the proton accelerators were room temperature linacs. In view of the progress relating to properties of RF superconducting resonators and the excellent accumulated experience with cryogenic accelerators, future accelerators for spallation sources will be mostly cryogenic linacs

  2. Spallation neutron sources

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  3. Beam dynamics simulation of the Spallation Neutron Source linear accelerator

    International Nuclear Information System (INIS)

    Takeda, H.; Billen, J.H.; Bhatia, T.S.

    1998-01-01

    The accelerating structure for Spallation Neutron Source (SNS) consists of a radio-frequency-quadrupole-linac (RFQ), a drift-tube-linac (DTL), a coupled-cavity-drift-tube-linac (CCDTL), and a coupled-cavity-linac (CCL). The linac is operated at room temperature. The authors discuss the detailed design of linac which accelerates an H - pulsed beam coming out from RFQ at 2.5 MeV to 1000 MeV. They show a detailed transition from 402.5 MHz DTL with a 4 βλ structure to a CCDTL operated at 805 MHz with a 12 βλ structure. After a discussion of overall feature of the linac, they present an end-to-end particle simulation using the new version of the PARMILA code for a beam starting from the RFQ entrance through the rest of the linac. At 1000 MeV, the beam is transported to a storage ring. The storage ring requires a large (±500-keV) energy spread. This is accomplished by operating the rf-phase in the last section of the linac so the particles are at the unstable fixed point of the separatrix. They present zero-current phase advance, beam size, and beam emittance along the entire linac

  4. 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

  5. A high power accelerator driver system for spallation neutron sources

    International Nuclear Information System (INIS)

    Jason, A.; Blind, B.; Channell, P.

    1996-01-01

    This is the final report of a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). For several years, the Los Alamos Meson Physics Facility (LAMPF) and the Proton Storage Ring (PSR) have provided a successful driver for the nearly 100-kW Los Alamos Neutron Scattering Center (LANSCE) source. The authors have studied an upgrade to this system. The goal of this effort was to establish a credible design for the accelerator driver of a next-generation source providing 1-MW of beam power. They have explored a limited subset of the possible approaches to a driver and have considered only the low 1-MW beam power. The next-generation source must utilize the optimum technology and may require larger neutron intensities than they now envision

  6. Overview of ten-year operation of the superconducting linear accelerator at the Spallation Neutron Source

    Science.gov (United States)

    Kim, S.-H.; Afanador, R.; Barnhart, D. L.; Crofford, M.; Degraff, B. D.; Doleans, M.; Galambos, J.; Gold, S. W.; Howell, M. P.; Mammosser, J.; McMahan, C. J.; Neustadt, T. S.; Peters, C.; Saunders, J. W.; Strong, W. H.; Vandygriff, D. J.; Vandygriff, D. M.

    2017-04-01

    The Spallation Neutron Source (SNS) has acquired extensive operational experience of a pulsed proton superconducting linear accelerator (SCL) as a user facility. Numerous lessons have been learned in its first 10 years operation to achieve a stable and reliable operation of the SCL. In this paper, an overview of the SNS SCL design, qualification of superconducting radio frequency (SRF) cavities and ancillary subsystems, an overview of the SNS cryogenic system, the SCL operation including SCL output energy history and downtime statistics, performance stability of the SRF cavities, efforts for SRF cavity performance recovery and improvement at the SNS, and maintenance activities for cryomodules are introduced.

  7. 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)

  8. Spallation Neutron Source (SNS)

    Data.gov (United States)

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

  9. 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

  10. 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

  11. Shielding around spallation neutron sources

    International Nuclear Information System (INIS)

    Fragopoulou, M; Manolopoulou, M; Stoulos, S; Brandt, R; Westmeier, W; Krivopustov, M; Sosnin, A; Golovatyuk, S; Zamani, M

    2006-01-01

    Spallation neutron sources provide more intense and harder neutron spectrum than nuclear reactors for which a substantial amount of shielding measurements have been performed. Although the main part of the cost for a spallation station is the cost of the shielding, measurements regarding shielding for the high energy neutron region are still very scarce. In this work calculation of the neutron interaction length in polyethylene moderator for different neutron energies is presented. Measurements which were carried out in Nuclotron accelerator at the Laboratory of High Energies (Joint Institute for Nuclear Research, Dubna) and comparison with calculation are also presented. The measurements were performed with Solid State Nuclear Track Detectors (SSNTDs)

  12. 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

  13. 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

  14. 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...

  15. 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.

  16. 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

  17. High-energy in-beam neutron measurements of metal-based shielding for accelerator-driven spallation neutron sources

    Science.gov (United States)

    DiJulio, D. D.; Cooper-Jensen, C. P.; Björgvinsdóttir, H.; Kokai, Z.; Bentley, P. M.

    2016-05-01

    Metal-based shielding plays an important role in the attenuation of harmful and unwanted radiation at an accelerator-driven spallation neutron source. At the European Spallation Source, currently under construction in Lund, Sweden, metal-based materials are planned to be used extensively as neutron guide substrates in addition to other shielding structures around neutron guides. The usage of metal-based materials in the vicinity of neutron guides however requires careful consideration in order to minimize potential background effects in a neutron instrument at the facility. Therefore, we have carried out a combined study involving high-energy neutron measurements and Monte Carlo simulations of metal-based shielding, both to validate the simulation methodology and also to investigate the benefits and drawbacks of different metal-based solutions. The measurements were carried out at The Svedberg Laboratory in Uppsala, Sweden, using a 174.1 MeV neutron beam and various thicknesses of aluminum-, iron-, and copper-based shielding blocks. The results were compared to geant4 simulations and revealed excellent agreement. Our combined study highlights the particular situations where one type of metal-based solution may be preferred over another.

  18. 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...

  19. 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)

  20. 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.

  1. Linac design for the European spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Klein, H. [Universitaet Postfach, Frankfurt am Main (Germany)

    1995-10-01

    A study group has started to develop a conceptual design for a European Spallation Source (ESS). This pulsed 5 MW source presently consists of a 1.334 GeV linac and two compressor rings. In the following mainly the high intensity linac part will be discussed, which has some features of interest for accelerators for transmutation of radioactive waste too.

  2. 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...

  3. Vacuum seals design and testing for a linear accelerator of the National Spallation Neutron Source

    International Nuclear Information System (INIS)

    Chen, Z.; Gautier, C.; Hemez, F.; Bultman, N.K.

    2000-01-01

    Vacuum seals are very important to ensure that the Spallation Neutron Source (SNS) Linac has an optimum vacuum system. The vacuum joints between flanges must have reliable seals to minimize the leak rate and meet vacuum and electrical requirements. In addition, it is desirable to simplify the installation and thereby also simplify the maintenance required. This report summarizes an investigation of the metal vacuum seals that include the metal C-seal, Energized Spring seal, Helcoflex Copper Delta seal, Aluminum Delta seal, delta seal with limiting ring, and the prototype of the copper diamond seals. The report also contains the material certifications, design, finite element analysis, and testing for all of these seals. It is a valuable reference for any vacuum system design. To evaluate the suitability of several types of metal seals for use in the SNS Linac and to determine the torque applied on the bolts, a series of vacuum leak rate tests on the metal seals have been completed at Los Alamos Laboratory. A copper plated flange, using the same type of delta seal that was used for testing with the stainless steel flange, has also been studied and tested. A vacuum seal is desired that requires significantly less loading than a standard ConFlat flange with a copper gasket for the coupling cavity assembly. To save the intersegment space the authors use thinner flanges in the design. The leak rate of the thin ConFlat flange with a copper gasket is a baseline for the vacuum test on all seals and thin flanges. A finite element analysis of a long coupling cavity flange with a copper delta seal has been performed in order to confirm the design of the long coupling cavity flange and the welded area of a cavity body with the flange. This analysis is also necessary to predict a potential deformation of the cavity under the combined force of atmospheric pressure and the seating load of the seal. Modeling of this assembly has been achieved using both HKS/Abaqus and COSMOS

  4. Physics and technology of spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.

    1998-08-01

    Next to fission and fusion, spallation is an efficient process for releasing neutrons from nuclei. Unlike the other two reactions, it is an endothermal process and can, therefore, not be used per se in energy generation. In order to sustain a spallation reaction, an energetic beam of particles, most commonly protons, must be supplied onto a heavy target. Spallation can, however, play an important role as a source of neutrons whose flux can be easily controlled via the driving beam. Up to a few GeV of energy, the neutron production is roughly proportional to the beam power. Although sophisticated Monte Carlo codes exist to compute all aspects of a spallation facility, many features can be understood on the basis of simple physics arguments. Technically a spallation facility is very demanding, not only because a reliable and economic accelerator of high power is needed to drive the reaction, but also, and in particular, because high levels of radiation and heat are generated in the target which are difficult to cope with. Radiation effects in a spallation environment are different from those commonly encountered in a reactor and are probably even more temperature dependent than the latter because of the high gas production rate. A commonly favored solution is the use of molten heavy metal targets. While radiation damage is not a problem in this case, except for the container, a number of other issues are discussed. (author)

  5. 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 ...

  6. 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

  7. 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)

  8. Decommissioning and safety issues of liquid-mercury waste generated from high power spallation sources with particle accelerators

    CERN Document Server

    Chiriki, S; Odoj, R; Moormann, R; Hinssen, H. K; Bukaemskiy, A

    2009-01-01

    Large spallation sources are intended to be constructed in Europe (EURISOL nuclear physics facility and ESS-European Spallation Source). These facilities accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Because solids are the only appropriate (immobile) form for this radiotoxic and toxic type of waste solidification is required for irradiated mercury. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in assumed accidents with water ingress in a repository compared to amalgams. For preparation of mercury sulfide a wet process is more suitable than a dry one. It is easier to perform under hot cell conditions and allows complete Hg-conversion. Embedding HgS in a cementitious matrix increases its stability.

  9. 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

  10. Thermal-hydraulic analysis of LBE spallation target for accelerator ...

    Indian Academy of Sciences (India)

    In an accelerator-driven subcritical system (ADS), a high-performance spallation neutron source is used to feed the subcritical reactor. Neutron generation depends on the proton beam intensity. If the beam intensity is increased by a given factor, the number of generated neutrons will increase. The mechanism yielding a ...

  11. China Spallation Neutron Source: Design, R&D, and outlook

    Science.gov (United States)

    Wei, Jie; Chen, Hesheng; Chen, Yanwei; Chen, Yuanbo; Chi, Yunlong; Deng, Changdong; Dong, Haiyi; Dong, Lan; Fang, Shouxian; Feng, Ji; Fu, Shinian; He, Lunhua; He, Wei; Heng, Yuekun; Huang, Kaixi; Jia, Xuejun; Kang, Wen; Kong, Xiangcheng; Li, Jian; Liang, Tianjiao; Lin, Guoping; Liu, Zhenan; Ouyang, Huafu; Qin, Qing; Qu, Huamin; Shi, Caitu; Sun, Hong; Tang, Jingyu; Tao, Juzhou; Wang, Chunhong; Wang, Fangwei; Wang, Dingsheng; Wang, Qingbin; Wang, Sheng; Wei, Tao; Xi, Jiwei; Xu, Taoguang; Xu, Zhongxiong; Yin, Wen; Yin, Xuejun; Zhang, Jing; Zhang, Zong; Zhang, Zonghua; Zhou, Min; Zhu, Tao

    2009-02-01

    The China Spallation Neutron Source (CSNS) is an accelerator based multidiscipline user facility planned to be constructed in Dongguan, Guangdong, China. The CSNS complex consists of an negative hydrogen linear accelerator, a rapid cycling proton synchrotron accelerating the beam to 1.6 GeV energy, 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. The primary challenge is to build a robust and reliable user's facility with upgrade potential at a fraction of "world standard" cost. We report the status, design, R&D, and upgrade outlook including applications using spallation neutron, muon, fast neutron, and proton, as well as related programs including medical therapy and accelerator-driven sub-critical reactor (ADS) programs for nuclear waste transmutation.

  12. 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.)

  13. 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.

  14. 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

  15. 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)

  16. Design Optimization and the path towards a 2 MW Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    M. Blaskiewicz; N. Catalan-Lasheras; D. Davino; A. Fedotov; Y. Lee; N. Malitsky; Y. Papaphilippou; D. Raparia; A. Shishlo; N. Tsoupas; J. Wei; W. Weng; S. Zhang; J. Billen; S. Kurennoy; S. Nath; J. Stovall; H. Takeda; L. Young; R. Keller; J. Staples; A. Aleksandrov; Y. Cho; P. Chu; S. Cousineau; V. Danilov; M. Doleans; J. Galambos; J. Holmes; N. Holtkamp; D. Jeon; S. Kim; R. Kustom; E. Tanke; W. Wan; R. Sundelin

    2001-08-01

    The Spallation Neutron Source (SNS) is designed to ultimately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups analyze the machine performance within the hardware constraints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source.

  17. Design Optimization and the path towards a 2 MW Spallation Neutron Source

    International Nuclear Information System (INIS)

    M. Blaskiewicz; N. Catalan-Lasheras; D. Davino; A. Fedotov; Y. Lee; N. Malitsky; Y. Papaphilippou; D. Raparia; A. Shishlo; N. Tsoupas; J. Wei; W. Weng; S. Zhang; J. Billen; S. Kurennoy; S. Nath; J. Stovall; H. Takeda; L. Young; R. Keller; J. Staples; A. Aleksandrov; Y. Cho; P. Chu; S. Cousineau; V. Danilov; M. Doleans; J. Galambos; J. Holmes; N. Holtkamp; D. Jeon; S. Kim; R. Kustom; E. Tanke; W. Wan; R. Sundelin

    2001-01-01

    The Spallation Neutron Source (SNS) is designed to ultimately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups analyze the machine performance within the hardware constraints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source

  18. DESIGN OPTIMIZATION AND THE PATH TOWARDS A 2 MW SPALLATION NEUTRON SOURCE

    International Nuclear Information System (INIS)

    WEI, J.; BLASKIEWICZ, M.; CATALAN-LASHERAS, N.; DAVINO, D.; FEDOTOV, A.; LEE, Y.Y.; MALITSKY, N.; ET AL

    2001-01-01

    The Spallation Neutron Source (SNS) is designed to ultimately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups analyze the machine performance within the hardware constraints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source

  19. Finite element analysis and frequency shift studies for the bridge coupler of the coupled cavity linear accelerator of the spallation neutron source.

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z. (Zukun)

    2001-01-01

    The Spallation Neutron Source (SNS) is an accelerator-based neutron scattering research facility. The linear accelerator (linac) is the principal accelerating structure and divided into a room-temperature linac and a superconducting linac. The normal conducting linac system that consists of a Drift Tube Linac (DTL) and a Coupled Cavity Linac (CCL) is to be built by Los Alamos National Laboratory. The CCL structure is 55.36-meters long. It accelerates H- beam from 86.8 Mev to 185.6 Mev at operating frequency of 805 MHz. This side coupled cavity structure has 8 cells per segment, 12 segments and 11 bridge couplers per module, and 4 modules total. A 5-MW klystron powers each module. The number 3 and number 9 bridge coupler of each module are connected to the 5-MW RF power supply. The bridge coupler with length of 2.5 {beta}{gamma} is a three-cell structure and located between the segments and allows power flow through the module. The center cell of each bridge coupler is excited during normal operation. To obtain a uniform electromagnetic filed and meet the resonant frequency shift, the RF induced heat must be removed. Thus, the thermal deformation and frequency shift studies are performed via numerical simulations in order to have an appropriate cooling design and predict the frequency shift under operation. The center cell of the bridge coupler also contains a large 4-inch slug tuner and a tuning post that used to provide bulk frequency adjustment and field intensity adjustment, so that produce the proper total field distribution in the module assembly.

  20. 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.

  1. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

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

  2. 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

  3. The status of the spallation neutron source ion source

    International Nuclear Information System (INIS)

    Welton, R.F.; Stockli, M.P.; Murray, S.N.; Keller, R.

    2003-01-01

    The ion source for the spallation neutron source (SNS) is a radio-frequency, multicusp source designed to deliver 45 mA of H2 to the SNS accelerator with a pulse length of 1 ms and repetition rate of 60 Hz. A total of three ion sources have been fabricated and commissioned at Lawrence Berkeley National Laboratory and subsequently delivered to the SNS at the Oak Ridge National Laboratory. The ion sources are currently being rotated between operation on the SNS accelerator, where they are involved in ongoing efforts to commission the SNS LINAC, and the hot spare stand (HSS), where high-current tests are in progress. Commissioning work involves operating the source in a low duty-factor mode (pulse width ∼200 ms and repetition rate ∼5 Hz) for extended periods of time while the high-current tests involve source operation at full duty-factor of 6 percent (1 ms/60 Hz). This report discusses routine performance of the source employed in the commissioning role as well as the initial results o f high-current tests performed on the HSS

  4. Decommissioning Plan for European Spallation Source

    Science.gov (United States)

    Ene, Daniela

    2017-09-01

    This paper is a survey of the European Spallation Source initial decommissioning plan developed in compliance with Swedish Regulatory Authority requirements. The report outlines the decommissioning strategy selected and the baseline plan for decommissioning. Types and quantities of radioactive waste estimated to be generated at the final shut-down of the facility are further provided. The paper ends up with the analysis of the key elements of the decommissioning plan and the recommendations to the ESS management team..

  5. Decommissioning Plan for European Spallation Source

    Directory of Open Access Journals (Sweden)

    Ene Daniela

    2017-01-01

    Full Text Available This paper is a survey of the European Spallation Source initial decommissioning plan developed in compliance with Swedish Regulatory Authority requirements. The report outlines the decommissioning strategy selected and the baseline plan for decommissioning. Types and quantities of radioactive waste estimated to be generated at the final shut-down of the facility are further provided. The paper ends up with the analysis of the key elements of the decommissioning plan and the recommendations to the ESS management team..

  6. Management of Tritium in European Spallation Source

    DEFF Research Database (Denmark)

    Ene, Daniela; Andersson, Kasper Grann; Jensen, Mikael

    2015-01-01

    The European Spallation Source (ESS) will produce tritium via spallation and activation processes during operational activities. Within the location of ESS facility in Lund, Sweden site it is mandatory to demonstrate that the management strategy of the produced tritium ensures the compliance...... with the country regulation criteria. The aim of this paper is to give an overview of the different aspects of the tritium management in ESS facility. Besides the design parameter study of the helium coolant purification system of the target the consequences of the tritium releasing into the environment were also...... analyzed. Calculations shown that the annual release of tritium during the normal operations represents a small fraction from the estimated total dose. However, more refined calculations of migration of activated-groundwater should be performed for higher hydraulic conductivities, with the availability...

  7. 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

  8. A comparison between short pulse spallation source and long pulse spallation source

    International Nuclear Information System (INIS)

    Aizawa, Kazuya; Watanabe, Noboru; Suzuki, Jun-ichi; Niimura, Nobuo; Morii, Yukio; Katano, Susumu; Osakabe, Toyotaka; Teshigawara, Makoto; Mezei, F.

    1997-01-01

    The performance for a 5 MW short pulse spallation source (SPSS) and a 4.5 MW long pulse spallation source (LPSS) in a JAERI program which is based on the availability of a 1.5 GeV superconducting linac with a 30 mA peak current for both proton and H - beams is discussed. We have examined the superiority of SPSS to LPSS. While a LPSS facility is a second option, we propose an SPSS facility as a first option. (author)

  9. 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...

  10. 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.

  11. 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

  12. The Spallation Neutron Source A Powerful Tool for Materials Research

    CERN Document Server

    Mason, Thomas E; Crawford, R K; Herwig, K W; Klose, F; Ankner, J F

    2005-01-01

    The wavelengths and energies of thermal and cold neutrons are ideally matched to the length and energy scales in the materials that underpin technologies of the present and future: ranging from semiconductors to magnetic devices, composites to biomaterials and polymers. The Spallation Neutron Source (SNS) will use an accelerator to produce the most intense beams of neutrons in the world when it is complete at the end of 2005. The project is being built by a collaboration of six U.S. Department of Energy laboratories. It will serve a diverse community of users drawn from academia, industry, and government labs with interests in condensed matter physics, chemistry, engineering materials, biology, and beyond.

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. 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.)

  18. Spallation neutron source and other high intensity froton sources

    International Nuclear Information System (INIS)

    Weiren Chou

    2003-01-01

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R and D program is included in an appendix

  19. Fission, spallation or fusion-based neutron sources

    Indian Academy of Sciences (India)

    The conclusion is that the route to high power neutron sources in the foreseeable future is spallation – short or long pulse or even CW – all of these sources will have areas in which they excel. Keywords. Neutron sources; spallation; fission; inertial confined fusion. PACS Nos 29.25.Dz; 25.40.Sc; 61.80.Hg; 28.20.Gd; 52.57.-z.

  20. 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

  1. Delayed-neutron fraction in a pulsed spallation neutron source

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1980-02-01

    The fraction of delayed neutrons β (with T/sub 1/2/ greater than or equal to 0.025 s) in slow-neutron beams from a 238 U pulsed spallation neutron source is 0.0053 for 300 MeV protons. This measurement appears to be the first one of this quantity. The result indicates that, for most classes of measurements, the delayed-neutron background in time-of-flight instruments will be unimportant, and places constraints on the physics description of spallation targets. The measurement was performed at the prototype pulsed spallation neutron source, ZING-P', at Argonne National laboratory. 4 figures

  2. Fundamental physics possibilities at the European Spallation Source

    DEFF Research Database (Denmark)

    Klinkby, Esben Bryndt; Batkov, Konstantin; Mezei, Ferenc

    2016-01-01

    The construction of the European Spallation has recently started in Lund, Sweden.In addition to the neutron scattering instruments the ESS is designed to serve, the constructionof a new spallation source opens up new possibilities for fundamental physics experiments. Inthis paper some of the poss......The construction of the European Spallation has recently started in Lund, Sweden.In addition to the neutron scattering instruments the ESS is designed to serve, the constructionof a new spallation source opens up new possibilities for fundamental physics experiments. Inthis paper some......-moderator-reector design that wouldallow for ultra cold neutron production and extraction. For completeness, the paper also discusspossible discovery physics experiments that are presently being studied in the framework of ESS.In parallel to the topics discussed here, work is ongoing investigating the scientic potential...... forin-beam fundamental physics experiments at the ESS....

  3. 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.

  4. Fission, spallation or fusion-based neutron sources

    Indian Academy of Sciences (India)

    In this paper the most promising technology for high power neutron sources is briefly discussed. The conclusion is that the route to high power neutron sources in the foreseeable future is spallation – short or long pulse or even CW – all of these sources will have areas in which they excel.

  5. 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.

  6. Technical design report of spallation neutron source facility in J-PARC

    International Nuclear Information System (INIS)

    Sakamoto, Shinichi

    2012-02-01

    One of the experimental facilities in Japan Proton Accelerator Research Complex (J-PARC) is the Materials and Life Science Experimental Facility (MLF), where high-intensity neutron beams are used as powerful probes for basic research on materials and life science, as well as research and development in industrial engineering. Neutrons are generated with nuclear spallation reaction by bombarding a mercury target with high-intensity proton beams. The neutrons are slowed down with supercritical hydrogen moderators and then extracted as beams to each experimental apparatus. The principal design of the spallation neutron source is compiled in this comprehensive report. (author)

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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

  14. Neutron science opportunities at pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1996-01-01

    Using the IPNS Upgrade plan developed at Argonne National Laboratory as a worked example of the design of a pulsed spallation neutron source, this paper explores some of the scientific applications of an advanced facility for materials science studies and the instrumentation for those purposes

  15. 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.)

  16. High-Power Linac for the Spallation Neutron Source

    Science.gov (United States)

    Rej, D. J.

    2002-04-01

    The Spallation Neutron Source (SNS) will be the world’s most intense source of neutrons for fundamental science and industrial applications. Design and construction of this facility, located at Oak Ridge, is a joint venture between six DOE laboratories. Construction began in 1999 and is currently ahead of the scheduled 2006 completion date. Injecting a high-power, pulsed proton beam into a mercury target produces neutrons. In this talk, we review the physics requirements, design, and status of the construction of the 1-GeV, 1.4-MW average power RF linac for SNS. The accelerator consists of a drift tube linac (DTL), a coupled-cavity linac (CCL), and a superconducting rf (SRF) linac. The phase and quadrupole settings are set to avoid structure and parametric resonances, with coherent resonances posing minimal risk for emittance growth. The DTL is 37 m long and accelerates the ions to 87 MeV. The CCL is 55 m long and accelerates the ions to 186 MeV. The rf structure design and stability for both the DTL and CCL have been validated with scale models. The SRF linac has a modular design to accelerate ions to 1000 MeV, with a straightforward upgrade to 1.3 GeV at a later date. 3D particle-in-cell simulations of beam dynamics are performed to validate performance. The accelerator utilizes 93 MW of pulsed power operating continuously at 60-Hz with an 8factor. Approximately one hundred 402.5 or 805-MHz klystrons, with outputs between 0.55 and 5 MW, are used. The klystrons are powered by a novel converter-modulator that takes advantage of recent advances in IGBT switch plate assemblies and low-loss material cores for boost transformer. Beam diagnostics include position, phase, profile, and current monitors. They are designed to enable accurate beam steering and matching, and to minimize beam loss that would lead to activation and prevent hands-on maintenance.

  17. 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

  18. 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

  19. Neutron scattering for polymer science at reactor and spallation sources

    International Nuclear Information System (INIS)

    Koizumi, Satoshi

    2009-01-01

    The neutron, having a variety of intrinsic properties (no charge, mass, spin and magnetic moment), is a marvelous probe to explore the structure of polymer materials. We report characteristic methods of small-angle neutron-neutron scattering (SANS), which are performed at reactor and spallation sources. A time-of-flight method at a spallation source employs neutrons of wide wavelength distribution in order to observe a wide length scale from angstrom to nanometer (from small-angle to wide-angle scattering regions). At a reactor source, on the other hand, a monochromatic neutron is utilized for precise observation of ultra-small-angle scattering, corresponding to a range from nano to micron meters. By combining both facilities, polymer science is further improved into exploring hierarchical structures in polymeric materials. (author)

  20. 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

  1. 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...

  2. 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.

  3. 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

  4. Monte Carlo simulation of NSE at reactor and spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Zsigmond, G.; Wechsler, D.; Mezei, F. [Hahn-Meitner-Institut Berlin, Berlin (Germany)

    2001-03-01

    A MC (Monte Carlo) computation study of NSE (Neutron Spin Echo) has been performed by means of VITESS investigating the classic and TOF-NSE options at spallation sources. The use of white beams in TOF-NSE makes the flipper efficiency in function of the neutron wavelength an important issue. The emphasis was put on exact evaluation of flipper efficiencies for wide wavelength-band instruments. (author)

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. The COHERENT Experiment at the Spallation Neutron Source

    OpenAIRE

    COHERENT Collaboration; Akimov, D.; An, P.; Awe, C.; Barbeau, P. S.; Barton, P.; Becker, B.; Belov, V.; Bolozdynya, A.; Burenkov, A.; Cabrera-Palmer, B.; Collar, J. I.; Cooper, R. J.; Cooper, R. L.; Cuesta, C.

    2015-01-01

    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 f...

  11. Spallation sources in support of technology

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-05-01

    In this contribution I summarize a number of recent experiments at the Los Alamos Neutron Science Center (LANSCE) that have contributed to strategic and applied research. A number of new tools have been developed to address these problems, including software that allows materials texture to be obtained during Rietveld refinement, Bragg-edge diffraction, resonant-neutron and proton radiography. These tools have the potential to impact basic as well as applied research. It is clear that a new, more powerful neutron source such as the planned Japanese Hadron Project will be able to use these and other techniques to contribute in a direct way to important industrial technologies. (author)

  12. Spallation sources in support of technology

    International Nuclear Information System (INIS)

    Pynn, R.

    1996-01-01

    In this contribution the author summarise a number of recent experiments at the Los Alamos Neutron Science Center (LANSCE) that have contributed to strategic and applied research. A number of new tools have been developed to address these problems, including software that allows materials texture to be obtained during Rietveld refinement, Bragg-edge diffraction, resonant-neutron and proton radiography. These tools have the potential to impact basic as well as applied research. It is clear that a new, more powerful neutron source such as the planned Japanese Hadron Project will be able to use these and other techniques to contribute in a direct way to important industrial technologies

  13. Thermal-hydraulic analysis of LBE spallation target for accelerator ...

    Indian Academy of Sciences (India)

    The mechanism yielding a high rate of neutron production per energy is the spallation process, and this mechanism produces very high-energy deposition in the ... Department of Engineering Physics, Tsinghua University, Beijing, 100084, China; Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, ...

  14. 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

  15. A neutron booster for spallation sources—application to accelerator driven systems and isotope production

    Science.gov (United States)

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

    2002-06-01

    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 μm-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 could be developed for spallation targets foreseen in the MYRRHA (L. Van Den Durpel, H. Aı̈t Abderrahim, P. D'hondt, G. Minsart, J.L. Bellefontaine, S. Bodart, B. Ponsard, F. Vermeersch, W. Wacquier. A prototype accelerator driven system in Belgium: the Myrrha project, Technical Committee Meeting on Feasibility and Motivation for Hybrid concepts for Nuclear Energy generation and Transmutation, Madrid, Spain, September 17-19, 1997 [1]). or MEGAPIE (M. Salvatores, G.S. Bauer, G. Heusener. The MEGAPIE initiative: executive outline and status as per November 1999, MPO-1-GB-6/0_GB, 1999 [2]) projects. With a neutron multiplication factor of the booster unit in the range 10-20 (i.e. with a keff of 0.9-0.95), considerably less powerful accelerators would be required to obtain the desired neutron flux. Instead of the powerful accelerators with proton energies of 1 GeV and currents of 10 mA foreseen for accelerator driven systems, similar neutron fluxes can be obtained

  16. 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

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

    International Nuclear Information System (INIS)

    Haines, J.R.; 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.

    2014-01-01

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

  18. 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

  19. 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.

  20. Powder diffraction on a long-pulse spallation source

    International Nuclear Information System (INIS)

    Stride, J.A.; Wechsler, D.; Mezei, F.; Bleif, H.-J.

    2000-01-01

    Monte Carlo simulations have been performed for a time-of-flight monochromator powder diffractometer housed on a thermal moderator at a Long-Pulse Spallation Source and for a conventional crystal monochromator instrument on a thermal moderator of a reactor source of four times the time-averaged flux. By designing the time-of-flight instrument to utilise the inherent advantages of the technique whilst optimising to the peak performance of the crystal monochromator case, the performance of the TOF-instrument is shown to exceed that of the reactor-based diffractometer, despite the lower time-averaged flux of the source. Further, a simple extrapolation of the results obtained for the pulsed-source shows that such a TOF diffractometer would out-perform a conventional instrument if both were to be housed on the same reactor

  1. Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source.

    Science.gov (United States)

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

    2014-02-01

    The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H(-) beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.

  2. 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.

  3. 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

  4. Overcoming high energy backgrounds at pulsed spallation sources

    International Nuclear Information System (INIS)

    Cherkashyna, Nataliia; Hall-Wilton, Richard J.; DiJulio, Douglas D.

    2016-01-01

    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 performance whilst at the same time delivering significant cost savings. A systematic holistic approach is suggested in this contribution to increase the effectiveness of this. Instrument performance should subsequently benefit. (author)

  5. 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.

  6. 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

  7. MC simulations of reflectometers at reactor and spallation sources

    CERN Document Server

    Lieutenant, K; Mezei, F

    2002-01-01

    We simulated spectra of reflectometers installed on pulsed sources as they are planned for the ESS (5 MW, 50 Hz short pulse, 1 MW, 10 Hz short pulse, and 5 MW, 16.67 Hz long pulse); for each of the sources a coupled moderator was used. For comparison of spallation and reactor sources, we simulated an instrument with equivalent parameters installed on a reactor source with a neutron flux of the ILL. For comparability of the data, constant wavelength and angular resolutions (of 3% and 8%) were used for all instruments. The intensity at the detector was determined as a function of the momentum transfer for a virtual sample of total reflectivity and for deuterated water. Finally, it was calculated how long it takes for each source to measure the entire spectrum with a given statistical accuracy. Best results were obtained at the 50 Hz short-pulse source and the long-pulse source, while the 10 Hz short-pulse source performed worse. The measuring time calculated for the reactor source was the longest. (orig.)

  8. Improved design of proton source and low energy beam transport line for European Spallation Source

    Science.gov (United States)

    Neri, L.; Celona, L.; Gammino, S.; Mascali, D.; Castro, G.; Torrisi, G.; Cheymol, B.; Ponton, A.; Galatà, A.; Patti, G.; Gozzo, A.; Lega, L.; Ciavola, G.

    2014-02-01

    The design update of the European Spallation Source (ESS) accelerator is almost complete and the construction of the prototype of the microwave discharge ion source able to provide a proton beam current larger than 70 mA to the 3.6 MeV Radio Frequency Quadrupole (RFQ) started. The source named PS-ESS (Proton Source for ESS) was designed with a flexible magnetic system and an extraction system able to merge conservative solutions with significant advances. The ESS injector has taken advantage of recent theoretical updates and new plasma diagnostics tools developed at INFN-LNS (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare). The design strategy considers the PS-ESS and the low energy beam transport line as a whole, where the proton beam behaves like an almost neutralized non-thermalized plasma. Innovative solutions have been used as hereinafter described. Thermo-mechanical optimization has been performed to withstand the chopped beam and the misaligned focused beam over the RFQ input collimator; the results are reported here.

  9. Improved design of proton source and low energy beam transport line for European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Neri, L., E-mail: neri@lns.infn.it; Celona, L.; Gammino, S.; Mascali, D.; Castro, G.; Ciavola, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Torrisi, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile, Università Mediterranea di Reggio Calabria, Via Graziella, 89122 Reggio Calabria (Italy); Cheymol, B.; Ponton, A. [European Spallation Source ESS AB, Lund (Sweden); Galatà, A. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell' università 2, 35020 Legnaro (Italy); Patti, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell' università 2, 35020 Legnaro (Italy); Gozzo, A.; Lega, L. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Ingegneria Informatica e delle Telecomunicazioni, Università degli Studi di Catania, Viale Andrea Doria 6, 95123 Catania (Italy)

    2014-02-15

    The design update of the European Spallation Source (ESS) accelerator is almost complete and the construction of the prototype of the microwave discharge ion source able to provide a proton beam current larger than 70 mA to the 3.6 MeV Radio Frequency Quadrupole (RFQ) started. The source named PS-ESS (Proton Source for ESS) was designed with a flexible magnetic system and an extraction system able to merge conservative solutions with significant advances. The ESS injector has taken advantage of recent theoretical updates and new plasma diagnostics tools developed at INFN-LNS (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare). The design strategy considers the PS-ESS and the low energy beam transport line as a whole, where the proton beam behaves like an almost neutralized non-thermalized plasma. Innovative solutions have been used as hereinafter described. Thermo-mechanical optimization has been performed to withstand the chopped beam and the misaligned focused beam over the RFQ input collimator; the results are reported here.

  10. 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

  11. The Lambertson Septum Magnet of the Spallation Neutron Source

    CERN Document Server

    Rank, Jim; Miglionico, Gary; Raparia, Deepak; Tsoupas, Nicholaos; Tuozzolo, Joseph; Wei, Jie; Yung Lee, Yong

    2005-01-01

    In the Spallation Neutron Source, at Oak Ridge National Laboratory in Tennessee, multiple-stage injections to an accumulator ring increase intensity until a final extraction delivers the full proton beam to the target via transfer line. This extraction is achieved by a series of kicker elements and a thin septum Extraction Lambertson Septum Magnet. Here we discuss the lattice geometry, beam dynamics and optics, and the vacuum, electromagnetic and electromechanical design aspects of the SNS Extraction Lambertson Septum Magnet. Relevant datums are established. Beam optics is studied. Vector calculus is solved for pitch and roll angles. Fundamental magnet sections are depicted schematically. Coil, pole and yoke design calculations and electromagnetics optimization are presented.

  12. 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

  13. 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

  14. EVOLUTION OF THE SPALLATION NEUTRON SOURCE RING LATTICE.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; CATALAN - LASHERAS,N.; FEDOTOV,A.; GARDNER,C.J.; LEE,Y.Y.; PAPAPHILIPPOU,Y.; RAPARIA,D.; TSOUPAS,N.; HOLMES,J.

    2002-04-08

    Requirements of minimum beam loss for hand-on maintenance and flexibility for future operations are essential for the lattice design of the Spallation Neutron Source (SNS) accumulator ring. During the past seven years, the lattice has evolved from an all-FODO to a FODO/doublet hybrid, the circumference has been increased to accommodate for a higher energy foreseen with a super-conducting RF linac, and the layout has evolved from an {alpha}- to an {Omega}-geometry. Extensive studies are performed to determine working points that accommodate injection painting and minimize beam losses due to space charge and resonances. In this paper, we review the evolution of the SNS ring lattice and discuss the rationales.

  15. CONSTRUCTION STATUS AND ISSUES OF THE SPALLATION NEUTRON SOURCE RING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.

    2004-07-05

    The Spallation Neutron Source (SNS) ring is designed to accumulate beam pulses of 1.5 x 10{sup 14} protons of 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity and power, key design challenges include control of beam loss and radio-activation, construction of high-quality large-aperture magnets and power supplies, design of robust injection and extraction systems, minimization of beam-coupling impedances, and mitigation of electron-cloud effects. This paper discusses the status of the ring systems with emphasis on technical challenges and issues, and presents future perspectives towards a next-generation high-intensity facility.

  16. High energy nuclear reactions ('Spallation') and their application in calculation of the Acceleration Driven Systems (ADS)

    International Nuclear Information System (INIS)

    Rossi, Pedro Carlos Russo

    2011-01-01

    This work presents a study of high energy nuclear reactions which are fundamental to dene the source term in accelerator driven systems. These nuclear reactions, also known as spallation, consist in the interaction of high energetic hadrons with nucleons in the atomic nucleus. The phenomenology of these reactions consist in two step. In the rst, the proton interacts through multiple scattering in a process called intra-nuclear cascade. It is followed by a step in which the excited nucleus, coming from the intranuclear cascade, could either, evaporates particles to achieve a moderate energy state or fission. This process is known as competition between evaporation and fission. In this work the main nuclear models, Bertini and Cugnon are reviewed, since these models are fundamental for design purposes of the source term in ADS, due to lack of evaluated nuclear data for these reactions. The implementation and validation of the calculation methods for the design of the source is carried out to implement the methodology of source design using the program MCNPX (Monte Carlo N-Particle eXtended), devoted to calculation of transport of these particles and the validation performed by an international cooperation together with a Coordinated Research Project (CRP) of the International Atomic Energy Agency and available jobs, in order to qualify the calculations on nuclear reactions and the de-excitation channels involved, providing a state of the art of design and methodology for calculating external sources of spallation for source driven systems. The CRISP, is a brazilian code for the phenomenological description of the reactions involved and the models implemented in the code were reviewed and improved to continue the qualification process. Due to failure of the main models in describing the production of light nuclides, the multifragmentation reaction model was studied. Because the discrepancies in the calculations of production of these nuclides are attributes to the

  17. 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

  18. Proton and Ion Sources for High Intensity Accelerators

    CERN Multimedia

    Scrivens, R

    2004-01-01

    Future high intensity ion accelerators, including the Spallation Neutron Source (SNS), the European Spallation Source (ESS), the Superconducting Proton Linac (SPL) etc, will require high current and high duty factor sources for protons and negative hydrogen ions. In order to achieve these goals, a comparison of the Electron Cyclotron Resonance, radio-frequency and Penning ion sources, among others, will be made. For each of these source types, the present operational sources will be compared to the state-of-the-art research devices with special attention given to reliability and availability. Finally, the future research and development aims will be discussed.

  19. 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.

  20. 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

  1. 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

  2. Cold moderators at pulsed spallation sources: A personal view

    International Nuclear Information System (INIS)

    Pynn, R.

    1991-01-01

    When Maier-Leibnitz built the ILL, he came first to the US and to Canada where there were several prominent neutron scattering centers. He asked what instruments he should build. The reply was unanimous: 'First you build some three-axis machines to form the base program and then you see what else you can thin of.' Maier-Leibnitz's reply was equally characteristic: 'Thank you very much hor-ellipsis there will be no three-axis spectrometers at my institute.' He wasn't quite right - there was one at the beginning. But the point is that, instead of following conventional wisdom, Maier-Leibnitz hired a bunch of young scientists who didn't know as much about neutron scattering as their colleagues on the American continent and who therefore did not know what was 'impossible.' So, they built the impossible - a cold source integrated into the reactor, several hundred meters of guides, a 40-meter SANS machine, a back-scattering spectrometer, a hedgehog - the whole works. And they changed the face of neutron scattering forever. The author is going to adopt the same philosophy - because he knows very little about cold moderators at spallation sources, he doesn't know what is possible or what is stupid. So he is going to make some outrageous comments to stimulate Peter Egelstaff's discussion session. He makes these remarks, not as Director of LANSCE, but as a research scientist looking well beyond his ares of expertise

  3. Numerical calculation of transverse coupling impedances: Comparison to Spallation Neutron Source extraction kicker measurements

    Science.gov (United States)

    Doliwa, B.; Arévalo, E.; Weiland, T.

    2007-10-01

    The study of beam dynamics and the localization of potential sources of instabilities are important tasks in the design of modern, high-intensity particle accelerators. In the case of synchrotrons and storage rings, coupling impedance data are needed to characterize the parasitic interaction of critical components with the beam. In this article we demonstrate the application of numerical field simulations to the computation of transverse kicker coupling impedances. Based on the 3D simulation results, a parametrized model is developed to incorporate the impedance of an arbitrary pulse-forming network attached to the kicker. Detailed comparisons of numerical results with twin-wire and direct measurements are discussed at the example of the Spallation Neutron Source extraction kicker.

  4. Numerical calculation of transverse coupling impedances: Comparison to Spallation Neutron Source extraction kicker measurements

    Directory of Open Access Journals (Sweden)

    B. Doliwa

    2007-10-01

    Full Text Available The study of beam dynamics and the localization of potential sources of instabilities are important tasks in the design of modern, high-intensity particle accelerators. In the case of synchrotrons and storage rings, coupling impedance data are needed to characterize the parasitic interaction of critical components with the beam. In this article we demonstrate the application of numerical field simulations to the computation of transverse kicker coupling impedances. Based on the 3D simulation results, a parametrized model is developed to incorporate the impedance of an arbitrary pulse-forming network attached to the kicker. Detailed comparisons of numerical results with twin-wire and direct measurements are discussed at the example of the Spallation Neutron Source extraction kicker.

  5. 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

  6. 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.

  7. 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

  8. Spallation Neutron Source High Power RF Installation and Commissioning Progress

    CERN Document Server

    McCarthy, Michael P; Bradley, Joseph T; Fuja, Ray E; Gurd, Pamela; Hardek, Thomas; Kang, Yoon W; Rees, Daniel; Roybal, William; Young, Karen A

    2005-01-01

    The Spallation Neutron Source (SNS) linac will provide a 1 GeV proton beam for injection into the accumulator ring. In the normal conducting (NC) section of this linac, the Radio Frequency Quadupole (RFQ) and six drift tube linac (DTL) tanks are powered by seven 2.5 MW, 402.5 MHz klystrons and the four coupled cavity linac (CCL) cavities are powered by four 5.0 MW, 805 MHz klystrons. Eighty-one 550 kW, 805 MHz klystrons each drive a single cavity in the superconducting (SC) section of the linac. The high power radio frequency (HPRF) equipment was specified and procured by LANL and tested before delivery to ensure a smooth transition from installation to commissioning. Installation of RF equipment to support klystron operation in the 350-meter long klystron gallery started in June 2002. The final klystron was set in place in September 2004. Presently, all RF stations have been installed and high power testing has been completed. This paper reviews the progression of the installation and testing of the HPRF Sys...

  9. 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.

  10. News from the continuous spallation neutron source SINQ

    International Nuclear Information System (INIS)

    Schefer, J.; Ch Rüegg; Wagner, W.; Clausen, K.

    2013-01-01

    The Swiss Spallation Neutron Source SINQ is a modern user facility for neutron diffraction, neutron scattering and imaging experiments. It started user service in 1998. Presently, 14 instruments are open for outside users and one is at the end of the commissioning phase, two instruments are reserved for testing new components and crystals quality, one is operated by industry. Together with the excellent sample environment ranging from high pressure, high field, very low and very high temperatures, computer controlled (low-temperature) sample changer to specialties such as insitu measurements under hydrogen, and the present flux (4 times higher than in 1998 as a consequence of increased proton flux as well as upgraded target). An upgrade program for the instrumentation as well as the guide system has been initiated to strengthen SINQ's competence in the next decade. We will present the present status of the facility; plans for the future upgrade program as well as highlights from the user service of the last few years. (author)

  11. 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)

  12. Low-Power RF Tuning of the Spallation Neutron Source Warm LINAC Structures

    CERN Document Server

    Deibele, C

    2004-01-01

    The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. A conventional 402.5 MHz drift-tube linac (DTL) accelerates the beam from 2.5 to 86 MeV, and the 805 MHz coupled-cavity linac (CCL) continues acceleration to 186 MeV. Tuning the six DTL tanks involves adjusting post-coupler lengths and slug tuners to achieve the design resonant frequency and stabilized field distribution. A 2.5 MW klystron feeds RF power into each DTL tank through a ridge-loaded waveguide that does not perturb either the frequency or field distribution in the tank. The CCL consists of 4 RF modules operating in the βλ/2 mode. Each module contains 96 accelerating cavities in 12 segments of 8 cavities each, 11 active bridge coupler cavities, and 106 nominally unexcited coupling cavities. For each RF module, power from a single 5 MW klystron splits once and drives bridge couplers 3 and 9. We will discuss the special tools and measurement techniques developed f...

  13. A feasibility study for a one-megawatt pulsed spallation source at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Pynn, R.

    1994-01-01

    Over the past two decades, high-intensity proton accelerators have been designed and developed to support nuclear physics research and defense applications. This technology has now matured to the point where it can support simultaneous and cost-effective exploitation of a number of important areas of both basic and applied science. Examples include neutron scattering, the production of radioisotopes, tests of technologies to transmute nuclear waste, radiation damage studies, nuclear physics, and muon spin research. As part of a larger program involving these and other areas, a team at Los Alamos National Laboratory has undertaken a feasibility study for a 1-MW pulsed spallation neutron source (PSS) based on the use of an 800-MeV proton linac and an accumulator ring. In January 1994, the feasibility study was reviewed by a large, international group of experts in the design of accelerators and neutron spallation targets. This group confirmed the viability of the proposed neutron source. In this paper, I describe the approach Los Alamos has taken to the feasibility study, which has involved a synergistic application of the Laboratory's expertise in nuclear science and technology, computation, and particle-beam technologies. Several examples of problems resolved by the study are described, including chopping of low-energy proton beam, interactions between H - particles and the stripper foil used to produce protons for injection into an accumulator ring, and the inclusion of engineering realities into the design of a neutron production target. These examples are chosen to illustrate the breadth of the expertise that has been brought to bear on the feasibility study and to demonstrate that there are real R ampersand D issues that need to be resolved before a next-generation spoliation source can be built

  14. 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).

  15. The Design Performance of the Integrated Spallation Neutron Source Vacuum Control System

    CERN Document Server

    Tang, Johnny Y; Ladd, Peter; Williams, Derrick

    2005-01-01

    The Spallation Neutron Source vacuum control systems have been developed within a collaboration of Lawrence Berkeley National Laboratory(LBNL), Los Alamos National Laboratory(LANL), Thomas Jefferson National Accelerator Facility(TJNAF), and Brookhaven National Laboratory(BNL). Each participating lab is responsible for a different section of the machine. Although a great deal of effort has been made to standardize vacuum instrumentation components and the global control system interfaces, the varied requirements of the different sections of the machine made horizontal integration of the individual vacuum control systems both interesting and challenging. To support commissioning, the SNS control system team and the vacuum group developed a set of test strategies and the interlock schemes that allowed horizontal vacuum system integration to be effectively achieved. The design of the vacuum control interlock scheme developed will be presented together with the results of performance measurements made on these sch...

  16. 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.

  17. Beam commission of the high intensity proton source developed at INFN-LNS for the European Spallation Source

    Science.gov (United States)

    Neri, L.; Celona, L.; Gammino, S.; Miraglia, A.; Leonardi, O.; Castro, G.; Torrisi, G.; Mascali, D.; Mazzaglia, M.; Allegra, L.; Amato, A.; Calabrese, G.; Caruso, A.; Chines, F.; Gallo, G.; Longhitano, A.; Manno, G.; Marletta, S.; Maugeri, A.; Passarello, S.; Pastore, G.; Seminara, A.; Spartà, A.; Vinciguerra, S.

    2017-07-01

    At the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS) the beam commissioning of the high intensity Proton Source for the European Spallation Source (PS-ESS) started in November 2016. Beam stability at high current intensity is one of the most important parameter for the first steps of the ongoing commissioning. Promising results were obtained since the first source start with a 6 mm diameter extraction hole. The increase of the extraction hole to 8 mm allowed improving PS-ESS performances and obtaining the values required by the ESS accelerator. In this work, extracted beam current characteristics together with Doppler shift and emittance measurements are presented, as well as the description of the next phases before the installation at ESS in Lund.

  18. Comparison of different antenna designs in the spallation neutron source negative hydrogen ion source

    Science.gov (United States)

    Veitzer, Seth A.; Kundrapu, Madhusudhan; Stoltz, Peter H.; Beckwith, Kristian R. C.

    2017-08-01

    Internal antenna negative hydrogen ion sources can fail when plasma heating causes ablation of the insulating coating due to small structural defects such as cracks. During this process, plasma ions impacting the surfaces of rf antennas causes heating of the coating, which can melt or ablate, thus exposing conducting surfaces to the plasma. Reducing antenna failures that reduce the operating capabilities of the Spallation Neutron Source (SNS) accelerator has been one of the top priorities of the SNS H-Source Program at ORNL. We have been utilizing numerical modeling of internal antenna negative hydrogen ion sources in order help optimize antenna designs in order to reduce antenna failures. We have implemented a number of fluid models with electromagnetics using the simulation tool USim and applied them to modeling the SNS internal antenna negative ion source. We report here on results comparing two different antenna designs. The baseline design, as is currently in use in the SNS source, and a wide-leg design, that has been tested, and may replace the baseline design if it can reduce antenna failures while still maintaining source performance. The wide-leg antenna is designed to move the antenna supports out of the high-density plasma regions, in order to decrease the possible negative effects of ion bombardment. We model the plasma evolution using a single-fluid MHD model with an imposed magnetic field due to the rf antenna current and the confining multi-cusp field for both the baseline and wide-leg antenna configurations. We find that the maximum plasma velocity near the antenna surfaces is reduced by nearly 50% in the wide-leg configuration, and that overall the bulk plasma velocity is reduced for this configuration. In addition, although we measure a small increase in the maximum plasma flux on the antenna surface for the wide-leg design, we see a broad-based reduction of plasma flux on the antenna in the regions where the antenna is mostly exposed to the

  19. 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

  20. 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

  1. 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.

  2. 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

  3. The Evolution of the Cryogenic System of the European Spallation Source

    Science.gov (United States)

    Hees, W.; Arnold, Ph; Fydrych, J.; Jurns, J.; Wang, X. L.; Weisend, J. G., II

    2015-12-01

    The European Spallation Source (ESS) is an intergovernmental project building a multidisciplinary research laboratory based upon the world's most powerful neutron source to be built in Lund, Sweden. The ESS will use a superconducting linear accelerator which will deliver protons with 5 MW of power to the target at 2.0 GeV with a nominal current of 62.5 mA. A cryomodule test stand will be supplied with helium for the site acceptance tests. The target will have two moderators using supercritical hydrogen to cool down the neutrons. The neutron instruments and the experiments’ sample environment will use liquid helium and liquid nitrogen to cool detectors and samples. The ESS cryogenic system is designed to deliver cryogenic cooling capacity to all three client system. A first concept of the ESS cryogenic system was developed in 2010 and 2011 with a limited amount of input from the clients as well as from site infrastructure (i.e. buildings and utilities). The design had to be flexible enough to accommodate future changes in scope, schedule and available infrastructure. Over the following years the design has evolved together with these parameters to achieve a maturity today which allowed us to order the accelerator cryoplant and to start procurement of many of the other parts of the ESS cryogenic system. This paper presents the evolution of the design throughout the years and the factors influencing certain design choices.

  4. Fermilab Project X nuclear energy application: Accelerator, spallation target and transmutation technology demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Yousry; /Argonne; Johnson, David; Johnson, Todd; Mishra, Shekhar; /Fermilab

    2011-04-01

    The recent paper 'Accelerator and Target Technology for Accelerator Driven Transmutation and Energy Production' and report 'Accelerators for America's Future' have endorsed the idea that the next generation particle accelerators would enable technological breakthrough needed for nuclear energy applications, including transmutation of waste. In the Fall of 2009 Fermilab sponsored a workshop on Application of High Intensity Proton Accelerators to explore in detail the use of the Superconducting Radio Frequency (SRF) accelerator technology for Nuclear Energy Applications. High intensity Continuous Wave (CW) beam from the Superconducting Radio Frequency (SRF) Linac (Project-X) at beam energy between 1-2 GeV will provide an unprecedented experimental and demonstration facility in the United States for much needed nuclear energy Research and Development. We propose to carry out an experimental program to demonstrate the reliability of the accelerator technology, Lead-Bismuth spallation target technology and a transmutation experiment of spent nuclear fuel. We also suggest that this facility could be used for other Nuclear Energy applications.

  5. 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

  6. 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.

  7. 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

  8. Background studies for the COHERENT experiment at the Spallation Neutron Source

    Science.gov (United States)

    Markoff, Diane M.; COHERENT Collaboration

    2017-09-01

    The COHERENT experiment is designed for a first measurement and N2 dependence study of coherent elastic neutrino-nucleus scattering (CEvNS) at the Oak Ridge Spallation Neutron Source (SNS). CEvNS is a standard model process that is important in understanding supernova neutrinos, the structure of the weak interaction and backgrounds for dark matter searches. The COHERENT collaboration is placing a suite of detector technologies in a basement location at the SNS: 14 kg CsI[Na] crystals; 185 kg NaI crystals; 35 kg single-phase LAr; 10kg high-purity, point contact Ge. Previous attempts to measure the CEvNS process have grappled with very high background rates. One class of troublesome backgrounds is accelerator-correlated neutrons because a simple accelerator on/off background subtraction procedure fails to remove these events. The collaboration has completed a comprehensive background study in the basement region where the experiments are located. We conclude from these studies that the neutron background is sufficiently low for successful CEvNS measurement in the SNS basement region. Neutron measurements from the Indiana University SciBath detector and the Sandia Neutron Scatter Camera are presented here.

  9. 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...

  10. High energy particle background at neutron spallation sources and possible solutions

    Science.gov (United States)

    Cherkashyna, N.; Kanaki, K.; Kittelmann, T.; Filges, U.; Deen, P.; Herwig, K.; Ehlers, G.; Greene, G.; Carpenter, J.; Connatser, R.; Hall-Wilton, R.; Bentley, P. M.

    2014-07-01

    Modern spallation neutron sources are driven by proton beams ~ GeV energies. Whereas low energy particle background shielding is well understood for reactors sources of neutrons (~20 MeV), for high energies (100s MeV to multiple GeV) there is potential to improve shielding solutions and reduce instrument backgrounds significantly. We present initial measured data on high energy particle backgrounds, which illustrate the results of particle showers caused by high energy particles from spallation neutron sources. We use detailed physics models of different materials to identify new shielding solutions for such neutron sources, including laminated layers of multiple materials. In addition to the steel and concrete, which are used traditionally, we introduce some other options that are new to the neutron scattering community, among which there are copper alloys as used in hadronic calorimeters in high energy physics laboratories. These concepts have very attractive energy absorption characteristics, and simulations predict that the background suppression could be improved by one or two orders of magnitude. These solutions are expected to be great benefit to the European Spallation Source, where the majority of instruments are potentially affected by high energy backgrounds, as well as to existing spallation sources.

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

    Science.gov (United States)

    Wang, Qing-Bin; Wu, Qing-Biao; Ma, Zhong-Jian; Zhang, Qing-Jiang; Li, Nan; Wu, Jing-Min; Liu, Jian; Zhang, Gang

    2010-07-01

    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 2.40×10-3 mSv/a to the public adult, and 2.29×10-3 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 3H, 7Be, 22Na, 54Mn, 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.

  12. 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)

  13. Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 2 workshop presentations

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, L.; Leung, Ka-Ngo; Alonso, J. [eds.

    1994-10-01

    As part of the Lawrence Berkeley Laboratory Pulsed Spallation Source study, this Workshop was convened to address ion-source technology`s present status with respect to the next-generation Pulsed Spallation Source in the 1-5 MW range for the neutron scattering community. Considerations of Low Energy Beam Transport (LEBT) parameters and designs were included in the discussions throughout the Workshop. Ion-source requirements and actually-achieved performances were assessed, resulting in a determination of research and development requirements to bridge the gap. Part 1 of these Proceedings summarizes the Workshop; Part 2 contains viewgraphs of Workshop presentations.

  14. 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

  15. Exploration of the Challenges of Neutron Optics and Instrumentation at Long Pulsed Spallation Sources

    DEFF Research Database (Denmark)

    Klenø, Kaspar Hewitt

    In this thesis I have explored the challenges of long guides and instrumentation for the long pulsed European Spallation Source. I have derived the theory needed for quantifying the performance of a guide using brilliance transfer. With this tool it is easier to objectively compare how well diffe...

  16. 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.)

  17. The EURISOL Multi Megawatt Target Station, a liquid metal target for a High Power spallation source.

    CERN Document Server

    Kharoua, C; Blumenfeld, L; Milenkovich, R; Wagner, W; Thomsen, K; Dementjevs, S; Platacis, E; Kravalis, K; Zik, A

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the ‘next-generation’ European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research in nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2013.In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW liquid metal proton-to-neutron converter, all driven by a high-power particle accelerator. In the aforementioned multi-MW target assembly, 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 presentation summarises the work carried out for the Multi Megawatt target station of the EURISOL Design Study with particular attention to the coupled neutronic of the liquid converter and the overall performance of the facility, which will sustain fast neutr...

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. {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.

  5. Design, status and first operations of the spallation neutron source polyphase resonant converter modulator system

    Energy Technology Data Exchange (ETDEWEB)

    Reass, W. A. (William A.); Apgar, S. E. (Sean E.); Baca, D. M. (David M.); Doss, James D.; Gonzales, J. (Jacqueline); Gribble, R. F. (Robert F.); Hardek, T. W. (Thomas W.); Lynch, M. T. (Michael T.); Rees, D. E. (Daniel E.); Tallerico, P. J. (Paul J.); Trujillo, P. B. (Pete B.); Anderson, D. E. (David E.); Heidenreich, D. A. (Dale A.); Hicks, J. D. (Jim D.); Leontiev, V. N.

    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 converter-modulator stations each providing between 9 and 11 MW pulses with up to a 1 .I MW average power. The converter-modulator can be described as a resonant 20 kHz polyphase boost inverter. Each converter modulator derives its buss voltage from a standard substation cast-core transformer. Each substation is followed by an SCR pre-regulator to accommodate voltage changes from no load to full load, in addition to providing a soft-start function. Energy storage is provided by self-clearing metallized hazy polypropylene traction capacitors. These capacitors do not fail short, but clear any internal anomaly. Three 'H-Bridge' IGBT transistor networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are time-gated to generate the desired klystron pulse width. Pulse width modulation of the individual 20 lcHz pulses is utilized to provide regulated output waveforms with DSP based adaptive feedforward and feedback techniques. The boost transformer design utilizes nanocrystalline alloy that provides low core loss at design flux levels and switching frequencies. Capacitors are used on the transformer secondary networks to resonate the leakage inductance. The transformers are wound for a specific leakage inductance, not turns ratio. This design technique generates multiple secondary volts per turn as compared to the primary. With the appropriate tuning conditions, switching losses are minimized. The resonant topology has the added benefit of being deQed in a klystron fault condition, with little energy deposited in the arc. This obviates the need of crowbars or other related networks. A review of these design parameters, operational performance, production status, and OWL installation and performance to date will be presented.

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

    Science.gov (United States)

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

    2016-06-01

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

  7. 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.

  8. 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)

  9. 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.

  10. Low-loss design for the high-intensity accumulator ring of the Spallation Neutron Source

    Directory of Open Access Journals (Sweden)

    J. Wei

    2000-08-01

    Full Text Available This paper summarizes the low-loss design for the Spallation Neutron Source accumulator ring [“Spallation Neutron Source Design Manual” (unpublished]. A hybrid lattice consisting of FODO arcs and doublet straights provides optimum matching and flexibility for injection and collimation. For this lattice, optimization focuses on six design goals: a space-charge tune shift low enough (below 0.15 to avoid strong resonances, adequate transverse and momentum acceptance for efficient beam collimation, injection optimized for desired target beam shape and minimal halo development, compensation of magnet field errors, control of impedance and instability, and prevention against accidental system malfunction. With an expected collimation efficiency of more than 90%, the uncontrolled fractional beam loss is expected to be at the 10^{-4} level.

  11. 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

  12. Electron Cloud in the Collimator- and Injection- Region of the Spallation Neutron Source's Accumulator Ring

    CERN Document Server

    Wang, Lanfa; Henderson, Stuart; Hseuh Hsiao Chaun; Lee, Yong Y; Raparia, Deepak; Wei, Jie

    2005-01-01

    The beam loss along the Spallation Neutron Source's (SNS's) accumulator ring is mainly located at the collimator region. From the ORBIT simulation, the peak power deposition at the three collimators is about 500, 350 and 240 W/m, respectively. Therefore, a sizeable number of electrons may be accumulated at this region due to the great beam loss. This paper simulated the electron cloud at the collimator region and the possible remedy.

  13. Technical concepts for a long-wavelength target station for the Spallation Neutron Source.

    CERN Document Server

    Carpenter, J M

    2002-01-01

    The Spallation Neutron Source (SNS), a major new user facility for materials research funded by the U.S. Department of Energy (DOE), is under construction at Oak Ridge National Laboratory (ORNL), see the Spallation Neutron Source web site at: www.sns.gov/aboutsns/source/htm. The SNS will operate at a proton beam power of 1.4 MW delivered in short pulses at 60 Hz; this power level is an order of magnitude higher than that of the current most intense pulsed spallation neutron facility in the world, ISIS at the Rutherford-Appleton Laboratory in the United Kingdom: 160 kW at 50 Hz. When completed in 2006, the SNS will supply the research community with neutron beams of unprecedented intensity and a powerful, diverse instrument suite with exceptional capabilities. Together, these will enable a new generation of experimental studies of interest to chemists, condensed matter physicists, biologists, materials scientists, and engineers, in an ever-increasing range of applications. The Long-Wavelength Target Station (L...

  14. 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.)

  15. 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.)

  16. In pursuit of a promise perspectives on the political process to establish the European Spallation Source (ESS) in Lund, Sweden

    CERN Document Server

    2012-01-01

    On 28 May 2009, at a closed meeting in Brussels, ministers and state secretaries of education and science from several EU countries decided to build the European Spallation Source (ESS) in Lund, Sweden. Or did they? It is common for big European science projects to be surrounded by secrecy and political deceit, but the ESS is extraordinary in its elusiveness. There is a remarkable lack of concrete economic, political, technical and scientific underpinnings to the project - but a boasting certainty in the promises of future paybacks. The ESS is an accelerator-based neutron spallation facility that will cost billions of Euros to build and run. It is expected to bring new knowledge in several fields including materials science, energy research, and the life sciences. But its financing is not yet certain, and future returns hard to predict. How then could the decision to build ESS occur? Why was there so little organized resistance? This book places the ESS project in its political and scientific context. It link...

  17. AC magnetic field measurement using a small flip coil system for rapid cycling AC magnets at the China Spallation Neutron Source (CSNS)

    Science.gov (United States)

    Zhou, Jianxin; Kang, Wen; Li, Shuai; Liu, Yudong; Liu, Yiqin; Xu, Shouyan; Guo, Xiaoling; Wu, Xi; Deng, Changdong; Li, Li; Wu, Yuwen; Wang, Sheng

    2018-02-01

    The China Spallation Neutron Source (CSNS) has two major accelerator systems, a linear accelerator and a rapid cycling synchrotron (RCS). The RCS accelerator is used to accumulate and accelerate protons from the energy of 80 MeV to the design energy of 1.6 GeV at the repetition rate of 25 Hz, and extract the high energy beam to the target. The main magnets of the RCS accelerator are excited by AC current with DC bias. The magnetic field quality is very important for the RCS accelerator operation, since it should guarantee and focus a circulating beam. In order to characterize the AC magnets, a small flip coil measurement system has been developed and one of each type of AC magnets has been studied. The measurement system and selected measurement results are presented in this paper.

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

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-06-01

    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.

  19. 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

  20. 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.

  1. 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.

  2. Small-angle neutron scattering at pulsed spallation sources

    International Nuclear Information System (INIS)

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

    1990-01-01

    The importance of small-angle neutron scattering (SANS) in biological, chemical, physical, and engineering research mandates that all intense neutron sources be equipped with SANS instruments. Four existing instruments are described, and the general differences between pulsed-source and reactor-based instrument designs are discussed. The basic geometries are identical, but dynamic range is achieved by using a broad band of wavelengths (with time-of-flight analysis) rather than by moving the detector. This allows a more optimized collimation system. Data acquisition requirements at a pulsed source are more severe, requiring large, fast histogramming memories. Data reduction is also more complex, as all wave length-dependent and angle-dependent backgrounds and non-linearities must be accounted for before data can be transformed to intensity vs Q. A comparison is shown between the Los Alamos pulsed instrument and D-11 (Institute Laue-Langevin), and examples from the four major topics of the conference are shown. The general conclusion is that reactor-based instruments remain superior at very low Q or if only a narrow range of Q is required, but that the current generation of pulsed-source instruments is competitive at moderate Q and may be faster when a wide range of Q is required. In principle, a user should choose which facility to use on the basis of optimizing the experiment; in practice the tradeoffs are not severe and the choice is usually made on the basis of availability

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

    Indian Academy of Sciences (India)

    enabling researchers from the United States and abroad to study materials science that forms the basis for new technologies in telecommunications, manufacturing, transporta- tion, information technology, biotechnology, and health. Keywords. Neutron scattering; neutron sources. PACS Nos 78.70.Nx; 29.25.Dz; 61.12.-q.

  4. Thermal chopper spectrometer for the European spallation source

    DEFF Research Database (Denmark)

    Klenø, Kaspar Hewitt; Lefmann, Kim

    2011-01-01

    One of the instruments being considered for the ESS is a thermal chopper spectrometer, intended for the study of lattice vibrations and magnetic excitations. However, as the ESS will be a long pulsed source, we propose a very long instrument (180–300 m). We here present a guide system that can ac...

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

    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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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

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

    DEFF Research Database (Denmark)

    Lefmann, Kim; Klenø, Kaspar H.; Birk, Jonas Okkels

    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...... 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...

  13. 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

  14. Nanodiamond Foils for H- Stripping to Support the Spallation Neutron Source (SNS) and Related Applications

    Energy Technology Data Exchange (ETDEWEB)

    Vispute, R D [Blue Wave Semiconductors; Ermer, Henry K [Blue Wave Semiconductors; Sinsky, Phillip [Blue Wave Semiconductors; Seiser, Andrew [Blue Wave Semiconductors; Shaw, Robert W [ORNL; Wilson, Leslie L [ORNL; Harris, Gary [Howard University; Piazza, Fabrice [Pontifica Universidad Catolica Madre y Maestra, Dominican Republic

    2013-01-01

    Thin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a single nanodiamond foil about the size of a postage stamp is critical to the entire operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control over film thickness. The results are discussed in the light of development

  15. 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.)

  16. 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.)

  17. 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.)

  18. Electron cloud development in the Proton Storage Ring and in the Spallation Neutron Source

    Directory of Open Access Journals (Sweden)

    M. T. F. Pivi

    2003-03-01

    Full Text Available We have applied our simulation code POSINST to evaluate the contribution to the growth rate of the electron cloud instability in proton storage rings. In particular, we present here recent simulation results for the main features of the electron cloud in the storage ring of the Spallation Neutron Source at Oak Ridge, and updated results for the Proton Storage Ring at Los Alamos. A key ingredient in our model is a detailed description of the secondary electron emission process, including a refined model for the emitted energy spectrum, and for the three main components of the secondary yield, namely, the true secondary, rediffused and backscattered components.

  19. Electron cloud development in the Proton Storage Ring and in theSpallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Pivi, M.T.F.; Furman, M.A.

    2002-10-08

    We have applied our simulation code "POSINST" to evaluatethe contribution to the growth rate of the electron-cloud instability inproton storage rings. Recent simulation results for the main features ofthe electron cloud in the storage ring of the Spallation Neutron Source(SNS) at Oak Ridge, and updated results for the Proton Storage Ring (PSR)at Los Alamos are presented in this paper. A key ingredient in our modelis a detailed description of the secondary emitted-electron energyspectrum. A refined model for the secondary emission process includingthe so-called true secondary, rediffused and backscattered electrons hasrecently been included in the electron-cloud code.

  20. 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)

  1. PRISMA - a spectrometer for the measurement of coherent excitations on a pulsed spallation neutron source

    International Nuclear Information System (INIS)

    Andreani, C.; Cilloco, F.; Petrillo, C.; Sacchetti, F.; Windsor, C.G.

    1986-04-01

    The measurement of nuclear and magnetic excitation spectra from single crystal samples remains central to condensed matter physics. The requirements in terms of the range and resolution of the scattering vector Q and energy transfer h/2πω are reviewed and typical experiments with a well defined cross-section are chosen. The performance and limitations of existing instruments are reviewed. A design for a new spectrometer, PRISMA, to be installed on the UK spallation neutron source, ISIS, is presented. Its performance for chosen experiments is given in terms of the Q and h/2πω range covered in a single scan, the resolution and the count rate. (author)

  2. Some safety studies of the MEGAPIE spallation source target performed using computational fluid dynamics

    International Nuclear Information System (INIS)

    Smith, B.L.

    2011-01-01

    Such a target forms part of the evolutionary Accelerator-Driven System (ADS) concept in which neutrons are generated in an otherwise sub-critical core by spallation reactions resulting from bombardment by a proton beam. The international project MEGAPIE had the objective of demonstrating the feasibility of the spallation process for a particular target design under strict test conditions. The test was carried over a period of four months at the end of 2006 at the SINQ facility of the Paul Scherrer Institute in Switzerland. The design studies carried out for the MEGAPIE target prior to irradiation using Computational Fluid Dynamics (CFD) resulted in an optimum flow configuration being defined for the coolant circulation. Simultaneously, stresses in the structural components were examined using Finite Element Method (FEM) techniques. To this purpose, an interface program was written which enabled different specialist groups to carry out the thermal hydraulics and structural mechanics analyses within the project with fully consistent model data. Results for steady-state operation of the target show that the critical lower target components are adequately cooled, and that stresses and displacements are well within tolerances. Transient analyses were also performed to demonstrate the robustness of the design in the event of abnormal operation, including pump failure and burn-through of the target casing by the proton beam. In the latter case, the CFD analyses complemented and extended full-scale tests. (author)

  3. The test beamline of the European Spallation Source – Instrumentation development and wavelength frame multiplication

    International Nuclear Information System (INIS)

    Woracek, R.; Hofmann, T.; Bulat, M.; Sales, M.; Habicht, K.; Andersen, K.; Strobl, M.

    2016-01-01

    The European Spallation Source (ESS), scheduled to start operation in 2020, is aiming to deliver the most intense neutron beams for experimental research of any facility worldwide. Its long pulse time structure implies significant differences for instrumentation compared to other spallation sources which, in contrast, are all providing short neutron pulses. In order to enable the development of methods and technology adapted to this novel type of source well in advance of the first instruments being constructed at ESS, a test beamline (TBL) was designed and built at the BER II research reactor at Helmholtz-Zentrum Berlin (HZB). Operating the TBL shall provide valuable experience in order to allow for a smooth start of operations at ESS. The beamline is capable of mimicking the ESS pulse structure by a double chopper system and provides variable wavelength resolution as low as 0.5% over a wide wavelength band between 1.6 Å and 10 Å by a dedicated wavelength frame multiplication (WFM) chopper system. WFM is proposed for several ESS instruments to allow for flexible time-of-flight resolution. Hence, ESS will benefit from the TBL which offers unique possibilities for testing methods and components. This article describes the main capabilities of the instrument, its performance as experimentally verified during the commissioning, and its relevance to currently starting ESS instrumentation projects.

  4. Ion sources for electrostatic accelerators

    International Nuclear Information System (INIS)

    Hellborg, R.

    1998-01-01

    Maybe the most important part of an electrostatic accelerator system, and also often the most tricky part is the ion source. There has been a rapid growth in activity in ion-source research and development during the last two to three decades. Some of these developments have also been of benefit to electrostatic accelerator users. In this report some of the different types of ion sources used in electrostatic accelerators are described. The list is not complete but more an overview of some of the more commonly used sources. The description is divided into two groups; positive ion sources for single stage electrostatic accelerators and negative ion sources for two stages (i.e. tandem) accelerators

  5. "Innovation and Intellectual Property Policies in European Research Infrastructure Consortia - PART I: The Case of the European Spallation Source ERIC"

    DEFF Research Database (Denmark)

    Yu, Helen; Wested, Jakob; Minssen, Timo

    2017-01-01

    of the problems society is facing today. To facilitate the creation and operation of such RIs, the EU adopted legal frameworks for European Research Infrastructure Consortia (ERIC). On August 31, 2015, the European Spallation Source (ESS) was established as an ERIC. Under the ERIC Regulations and ESS Statutes......, the European Spallation Source ERIC is required to adopt various policy documents relating to the operation and management of the facility. These cover a wide variety of issues such as user access, public procurement, intellectual property rights (IPR), data management, and dissemination. One of the main goals...... international research collaborations? The complex relationship between scientific excellence, innovation, and IPRs must be carefully considered. Taking the European Spallation Source ERIC as an example, this article investigates ERIC Regulations and EU policies and discusses what issues and perspectives ERICs...

  6. China high-intensity accelerator technology developments for neutron sources and accelerator driven systems

    International Nuclear Information System (INIS)

    Wei, J.; Fu, S.N.

    2010-01-01

    There have been aggressive developments in China on the technology of high intensity hadron accelerators for spallation neutron source, compact neutron source, accelerator driven sub-critical systems (ADS), and other related programs including hadron therapy. The primary challenge is to build a robust facility at a fraction of the 'world standard' cost. Benefiting from a close collaboration with world leading institutes and facilities, tremendous efforts were made in China to develop domestic vendors to comprehend the technology for key systems of high intensity ion source, linear accelerators, and rapid cycling synchrotron. Goals of such facilities include spallation-neutron-based, muon-based, and proton-based platforms for multi-discipline science and industrial applications, fast-neutron-based platform for nuclear science and applications, and parasitic apparatus for medical therapy and ADS tests. This paper attempts to summarize the R and D efforts, key component prototyping and vendor development experience, and user development efforts during the past several years in China. (author)

  7. 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-01

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

  9. 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.

  10. Conceptual design of a rapid-cycling synchrotron for the KFA-Juelich spallation neutron source: working papers

    International Nuclear Information System (INIS)

    1983-01-01

    An accelerator group was established at ANL by the request of KFA-Juelich to carry out a conceptual design study and cost estimate for a rapid-cycling synchrotron as a possible first stage program on spallation neutron sources at KFA-Juelich. This set of notes is the individual notes which form the basis of the final report under this proposal prepared in January 1983. The topics covered include: SNQ Synchrotron Lattice-I; injection and extraction orbit; extraction from SNQ-SRA; SRA injection; capture and acceleration considerations in the SNQ-SRA; longitudinal coupling impedance; power supplies for SNQ synchrotron proposals; space charge limits in the SNQ-SRA; error analysis; SNQ-SRA ring magnets preliminary designs and cost; summary of CERN booster 4-ring arrangement; V-lattices for SNQ-SRA and extraction from the V-lattices; rf parameters for capture, acceleration and extraction; some parameters of the SNQ-SRA injector system; Keil-Schnell criterion; risetime of longitudinal resistive wall instability; beam scrapers; a design of the vacuum system; some aspects of vacuum consideration for SNQ-SRA; choice working points; ring magnet power supplies for shaped extaction of 1.1 GeV SNQ; ring magnet design and costs; tune shift due to the fringing field of the quadrupoles; coherent instability due to ions in the residual gas; transverse stabilization of bunched beams; rf acceleration system; injection into the SRA; Landau damping to get transverse stability; chromaticity and amplitude dependent tune controls in the SNQ-SRA; conversion of the SNQ-SRA to a compressor ring; comments on beam loss; summary of longitudinal stability study and transverse stability study for the SNQ-SRA; and the beam stay clear regions of the SNQ-SRA

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

    CERN Document Server

    Futakawa, M; Conrad, H; Stechemesser, H

    2000-01-01

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

  12. Ion sources for medical accelerators

    Science.gov (United States)

    Barletta, W. A.; Chu, W. T.; Leung, K. N.

    1998-02-01

    Advanced injector systems for proton synchrotrons and accelerator-based boron neutron capture therapy systems are being developed at the Lawrence Berkeley National Laboratory. Multicusp ion sources, particularly those driven by radio frequency, have been tested for these applications. The use of a radio frequency induction discharge provides clean, reliable, and long-life source operation. It has been demonstrated that the multicusp ion source can provide good-quality positive hydrogen ion beams with a monatomic ion fraction higher than 90%. The extractable ion current densities from this type of source can meet the injector requirements for both proton synchrotron and accelerator-based boron neutron capture therapy projects.

  13. Spallation Neutron Source Availability Top-Down Apportionment Using Characteristic Factors and Expert Opinion

    International Nuclear Information System (INIS)

    Haire, M.J.; Schryver, J.C.

    1999-01-01

    Apportionment is the assignment of top-level requirements to lower tier elements of the overall facility. A method for apportioning overall facility availability requirements among systems and subsystems is presented. Characteristics that influence equipment reliability and maintainability are discussed. Experts, using engineering judgment, scored each characteristic for each system whose availability design goal is to be established. The Analytic Hierarchy Process (AHP) method is used to produce a set of weighted rankings for each characteristic for each alternative system. A mathematical model is derived which incorporates these weighting factors. The method imposes higher availability requirements on those systems in which an incremental increase in availability is easier to achieve, and lower availability requirements where greater availability is more difficult and costly. An example is given of applying this top-down apportionment methodology to the Spallation Neutron Source (SNS) facility

  14. Conceptual design of a cold methane moderator system for the European Spallation Source (ESS)

    CERN Document Server

    Barnert-Wiemer, H

    2002-01-01

    As part of the work for the target station of the planned European spallation source (ESS) the Central Department of Technology at the Forschungszentrum Juelich GmbH is also concerned with the moderators, particular attention being given to the development of cold methane moderators. This report discusses the technical feasibility of solid methane moderators. Methods to tailor the neutron output by adding absorption materials (decouplers or poisons) are not considered here, neither are composite moderators. Based on the given target-moderator-reflector assembly of the ESS project a concept for the ESS cold methane moderators has been developed and is being examined at the Forschungszentrum Juelich. According to this moderator concept the moderator is a fixed bed of small spheres, which makes moderator container filling homogeneous and reproducible. Since spheres form a defined packed bed, cooling of the moderator bed by H sub 2 is reliable. The process of filling the moderator container and of removing the pe...

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

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, F.; Hibiki, T.; Saito, Y.; Takeda, T.; Mishima, K. [Kyoto Univ., Research Reactor Institute (Japan)

    2001-07-01

    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)

  16. 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.

  17. 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 ...

  18. 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

  19. 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

  20. A Large Neutrino Detector Facility at the Spallation Neutron Source at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Efremenko, Y.V.

    1999-01-01

    The ORLaND (Oak Ridge Large Neutrino Detector) collaboration proposes to construct a large neutrino detector in an underground experimental hall adjacent to the first target station of the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory. The main mission of a large (2000 ton) Scintillation-Cherenkov detector is to measure bar ν μ -> bar ν e neutrino oscillation parameters more accurately than they can be determined in other experiments, or significantly extending the covered parameter space below (sin'20 le 10 -4 ). In addition to the neutrino oscillation measurements, ORLaND would be capable of making precise measurements of sin 2 θ W , search for the magnetic moment of the muon neutrino, and investigate the anomaly in the KARMEN time spectrum, which has been attributed to a new neutral particle. With the same facility an extensive program of measurements of neutrino nucleus cross sections is also planned to support nuclear astrophysics

  1. European Spallation Source ESS. Spanish participation in the ESS Primary system design; Fuente Europea de Spallation ESS. Participacion espanola en el diseno del sistema primario de la ESS

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, M. T.; Albisu, F.

    2001-07-01

    Neutron scattering provides basic microscopic information on the structure and dynamics of materials which underpins our understanding of condensed matter in fields as diverse as biology, material science chemistry, earth sciences and physics. Europe is preeminent, in this field and the current proposal for a next generation neutron source, the European Spallation source (ESS), will ensure that neutron beams of the highest quality are available early next century to a broad spectrum of users from academia and industry. In the Large Facilities Report to the Commission of the European Community (CEC) in 1990, the Neutron Study Panel underlined the continuing need for neutron scattering and recognised that a major initiative was necessary to secure an effective on-going neutron science programme in Europe for the year 2000 and beyond. (Author)

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. Overview of the conceptual design of the future VENUS beamline at the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Bilheux, Hassina Z [ORNL; Herwig, Kenneth W [ORNL; Keener, Wylie S [ORNL; Davis, Larry E [ORNL

    2015-01-01

    VENUS 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 m). 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 Beamline 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

  13. The CENNS-10 liquid argon detector to measure CEvNS at the Spallation Neutron Source

    Science.gov (United States)

    Tayloe, R.

    2018-04-01

    The COHERENT collaboration is deploying a suite of low-energy detectors in a low-background corridor of the ORNL Spallation Neutron Source (SNS) to measure coherent elastic neutrino-nucleus scattering (CEvNS) on an array of nuclear targets employing different detector technologies. A measurement of CEvNS on different nuclei will test the N2-dependence of the CEvNS cross section and further the physics reach of the COHERENT effort. The first step of this program has been realized recently with the observation of CEvNS in a 14.6 kg CsI detector. Operation and deployment of Ge and NaI detectors are also underway. A 22 kg, single-phase, liquid argon detector (CENNS-10) started data-taking in Dec. 2016 and will provide results on CEvNS from a lighter nucleus. Initial results indicate that light output, pulse-shape discrimination, and background suppression are sufficient for a measurement of CEvNS on argon.

  14. Final environmental impact statement, construction and operation of the Spallation Neutron Source. Volume 2

    International Nuclear Information System (INIS)

    1999-04-01

    DOE issued the ''Draft Environmental Impact Statement: Construction and Operation of the Spallation Neutron Source'' in December 1998. This document was made available for review by federal agencies; tribal governments; the state of Tennessee, New Mexico, Illinois, and New York; local governments; and the general public. DOE invited comments on the accuracy and adequacy of the DEIS and any other matters pertaining to environmental review of the document. The formal review and comment period extended from December 24, 1998 until February 8, 1999. DOE considered all comments submitted after the review and comment period. This appendix to the Final Environmental Impact Statement (FEIS) contains the 206 comments received and the DOE responses to these comments. It consists of four chapters. Chapter 1 provides an introduction to the contents of this appendix and discusses the general methodology DOE used for documenting, considering, and responding to the review comments on the DEIS. Chapter 2 summarizes the principal issues of public concern collectively reflected by the comments and presents DOE's responses to these issues. The full texts of the comments on the DEIS are presented in Chapter 3. Chapter 4 contains DOE's written responses to these comments and the locations of textual changes in the FEIS that were made in response to the comments

  15. 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...

  16. 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.

  17. 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.

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

    Science.gov (United States)

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

    2016-09-01

    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.

  19. 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

  20. 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

  1. High Field Pulsed Magnets for Neutron Scattering at the Spallation Neutron Source

    Science.gov (United States)

    Granroth, G. E.; Lee, J.; Fogh, E.; Christensen, N. B.; Toft-Petersen, R.; Nojiri, H.

    2015-03-01

    A High Field Pulsed Magnet (HFPM) setup, is in use at the Spallation Nuetron Source(SNS), Oak Ridge National Laboratory. With this device, we recently measured the high field magnetic spin structure of LiNiPO4. The results of this study will be highlighted as an example of possible measurements that can be performed with this device. To further extend the HFPM capabilities at SNS, we have learned to design and wind these coils in house. This contribution will summarize the magnet coil design optimization procedure. Specifically by varying the geometry of the multi-layer coil, we arrive at a design that balances the maximum field strength, neutron scattering angle, and the field homogeneity for a specific set of parameters. We will show that a 6.3kJ capacitor bank, can provide a magnetic field as high as 30T for a maximum scattering angle around 40° with homogeneity of +/- 4 % in a 2mm diameter spherical volume. We will also compare the calculations to measurements from a recently wound test coil. This work was supported in part by the Lab Directors' Research and Development Fund of ORNL.

  2. The COHERENT neutrino-nucleus scattering research program at the ORNL Spallation Neutron Source

    Science.gov (United States)

    Markoff, Diane; Coherent Collaboration

    2017-09-01

    The objective of the COHERENT project is to unambiguously measure the Coherent Elastic Neutrino (v) Nucleus Scattering (CEvNS) on a suite of target nuclei. The coherent interaction observable involves nuclear recoil energies on the order of a few tens of keV which has eluded measurements for over 40 years. The COHERENT collaboration is applying new detector technologies with multiple targets and performing rigorous background and detector characterization studies to observe the expected cross section and the dependence on the square of the neutron number, N2. The suite of targets including CsI[Na], LAr, NaI[Tl] and Ge are located at the ORNL Spallation Neutron Source which provides a high flux of pulsed neutrinos with a favorable energy distribution. Background studies include environmental neutron flux and neutron induced neutrino (NIN) rates, and characterization studies include measurements of the target material quenching factors. The CEvNS reaction rate is of interest for supernovae models, dark matter detector backgrounds, a means to study neutron distribution functions or form factors, and ultimately for neutrino physics tests of non-standard interactions and physics beyond the Standard Model. This talk will present the overall COHERENT program and detector status.

  3. Final design, fluid dynamic and structural mechanical analysis of a liquid hydrogen Moderator for the European Spallation Source

    Science.gov (United States)

    Bessler, Y.; Henkes, C.; Hanusch, F.; Schumacher, P.; Natour, G.; Butzek, M.; Klaus, M.; Lyngh, D.; Kickulies, M.

    2017-02-01

    The European Spallation Source (ESS) is currently in the construction phase and should have first beam on Target in 2019. ESS, located in Sweden, will be the most powerful spallation neutron source worldwide, with the goal to produce neutrons for research. As an in-kind partner the Forschungszentrum Juelich will among others, design and manufacture the four liquid hydrogen Moderators, which are located above and below the Target. Those vessels are confining the cold hydrogen used to reduce the energy level of the fast neutrons, produced by spallation in the Target, in order to make the neutrons usable for neutron scattering instruments. Due to the requirements [1], a fluid dynamic analysis with pressure and temperature depended hydrogen data, taking into account the pseudo critical phenomena and the pulsed neutronic heating (pressure waves) is necessary. With the fluid dynamic results, a structure mechanical analysis including radiation damage investigation (RCC-MRx code [5]), low temperature properties as well as strength reduction by welding can be realized. Finally, the manufacturing and welding completes the design process.

  4. 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

  5. The Source Equivalence Acceleration Method

    International Nuclear Information System (INIS)

    Everson, Matthew S.; Forget, Benoit

    2015-01-01

    Highlights: • We present a new acceleration method, the Source Equivalence Acceleration Method. • SEAM forms an equivalent coarse group problem for any spatial method. • Equivalence is also formed across different spatial methods and angular quadratures. • Testing is conducted using OpenMOC and performance is compared with CMFD. • Results show that SEAM is preferable for very expensive transport calculations. - Abstract: Fine-group whole-core reactor analysis remains one of the long sought goals of the reactor physics community. Such a detailed analysis is typically too computationally expensive to be realized on anything except the largest of supercomputers. Recondensation using the Discrete Generalized Multigroup (DGM) method, though, offers a relatively cheap alternative to solving the fine group transport problem. DGM, however, suffered from inconsistencies when applied to high-order spatial methods. While an exact spatial recondensation method was developed and provided full spatial consistency with the fine group problem, this approach substantially increased memory requirements for realistic problems. The method described in this paper, called the Source Equivalence Acceleration Method (SEAM), forms a coarse-group problem which preserves the fine-group problem even when using higher order spatial methods. SEAM allows recondensation to converge to the fine-group solution with minimal memory requirements and little additional overhead. This method also provides for consistency when using different spatial methods and angular quadratures between the coarse group and fine group problems. SEAM was implemented in OpenMOC, a 2D MOC code developed at MIT, and its performance tested against Coarse Mesh Finite Difference (CMFD) acceleration on the C5G7 benchmark problem and on a 361 group version of the problem. For extremely expensive transport calculations, SEAM was able to outperform CMFD, resulting in speed-ups of 20–45 relative to the normal power

  6. Recent performance of the Intense Pulsed Neutron Source accelerator system

    International Nuclear Information System (INIS)

    Potts, C.; Brumwell, F.; Rauchas, A.; Stipp, V.; Volk, G.; Donley, L.

    1987-03-01

    The Intense Pulsed Neutron Source (IPNS) accelerator system has now been in operation as part of a national user program for over five years. During that period steady progress has been made in both beam intensity and reliability. Almost 1.8 billion pulses totaling 4 x 10 21 protons have now been delivered to the spallation neutron target. Recent weekly average currents have reached 15 μA (3.2 x 10 12 protons per pulse, 30 pulses per second) and short-term peaks of almost 17 μA have been reached. In fact, the average current for the last two years is up 31% over the average for the first three years of operation

  7. 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

  8. Monte Carlo analysis of accelerator-driven systems studies on spallation neutron yield and energy gain

    CERN Document Server

    Hashemi-Nezhad, S R; Westmeier, W; Bamblevski, V P; Krivopustov, M I; Kulakov, B A; Sosnin, A N; Wan, J S; Odoj, R

    2001-01-01

    The neutron yield in the interaction of protons with lead and uranium targets has been studied using the LAHET code system. The dependence of the neutron multiplicity on target dimensions and proton energy has been calculated and the dependence of the energy amplification on the proton energy has been investigated in an accelerator-driven system of a given effective multiplication coefficient. Some of the results are compared with experimental findings and with similar calculations by the DCM/CEM code of Dubna and the FLUKA code system used in CERN. (14 refs).

  9. Development of nanodiamond foils for H- stripping to Support the Spallation Neutron Source (SNS) using hot filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Vispute, R D [Blue Wave Semiconductors; Ermer, Henry K [Blue Wave Semiconductors; Sinsky, Phillip [Blue Wave Semiconductors; Seiser, Andrew [Blue Wave Semiconductors; Shaw, Robert W [ORNL; Wilson, Leslie L [ORNL

    2014-01-01

    Thin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a small foil about the size of a postage stamp is critical to the operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control film thickness. The results are discussed in the light of development of nanodiamond foils that

  10. 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.

  11. 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.)

  12. Multi-MW Spallation Neutron Sources: Current Challenges and Future Prospects, 16th, 17th and 18th March 2009 in Bilbao (Spain)

    International Nuclear Information System (INIS)

    2009-01-01

    The strategy of building a multi MW, accelerator based spallation neutron source as the next generation neutron facility for Europe has been validated by the successful commissioning and operation of the SNS in the US (now operating close to 1 MW beam power) and the JPARC facility in Japan. However, since the original baseline design of ESS was completed in 2002, the underlying technology has advanced and some considerable experience has been gathered from these new facilities. Hence as Europe prepares for the construction of ESS, the time is ripe to learn from ongoing experience and define the development areas which would allow the ESS to take the most advantage from recent advances in technology while maintaining a reliable, low risk, design. The goal of the workshop, organized by the ESS Bilbao consortium, was to assess the current challenges facing multi-MW spallation sources and, taking into account synergies with other international projects of a similar nature, outline a road map for a collaborative Research and Development program that would enable Europe to meet these challenges for the timely construction of ESS. The full reports and recommendations from the various working groups are provided in the following pages. They lay the foundation for a road map for a collaborative development program which will enable the ESS to take full advantage of the relevant expertise which is distributed across various facilities and countries within Europe to produce a truly European facility at the forefront of the technology. This report is a witness to the willingness of a great many people to share their experiences and knowledge in an open and cooperative environment. (Author)

  13. Quantum molecular dynamics approach to estimate spallation yield ...

    Indian Academy of Sciences (India)

    Production of radioactive gases like tritium and other long-lived radiotoxic elements may require special radiation safety provisions. An important quantity in the design of a spallation source is the neutron cost, which involves the neutron yield and the running cost of the accelerator. This cost is inversely proportional to the ...

  14. 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

  15. Shielding calculations in support of the Spallation Neutron Source (SNS) proton beam transport system

    International Nuclear Information System (INIS)

    Johnson, Jeffrey O.; Gallmeier, Franz X.; Popova, Irina

    2002-01-01

    Determining the bulk shielding requirements for accelerator environments is generally an easy task compared to analyzing the radiation transport through the complex shield configurations and penetrations typically associated with the detailed Title II design efforts of a facility. Shielding calculations for penetrations in the SNS accelerator environment are presented based on hybrid Monte Carlo and discrete ordinates particle transport methods. This methodology relies on coupling tools that map boundary surface leakage information from the Monte Carlo calculations to boundary sources for one-, two-, and three-dimensional discrete ordinates calculations. The paper will briefly introduce the coupling tools for coupling MCNPX to the one-, two-, and three-dimensional discrete ordinates codes in the DOORS code suite. The paper will briefly present typical applications of these tools in the design of complex shield configurations and penetrations in the SNS proton beam transport system

  16. Comparison of different target material options for the European Spallation Source based on certain aspects related to the final disposal

    Science.gov (United States)

    Kókai, Zsófia; Török, Szabina; Zagyvai, Péter; Kiselev, Daniela; Moormann, Rainer; Börcsök, Endre; Zanini, Luca; Takibayev, Alan; Muhrer, Günter; Bevilacqua, Riccardo; Janik, József

    2018-02-01

    Different target options have been examined for the European Spallation Source, which is under construction in Lund, Sweden. During the design update phase, parameters and characteristics for the target design have been optimized not only for neutronics but also with respect to the waste characteristics related to the final disposal of the target. A rotating, solid tungsten target was eventually selected as baseline concept; the other options considered included mercury and lead-bismuth (LBE) targets suitable for a pulsed source. Since the licensee is obliged to present a decommissioning plan even before the construction phase starts, the radioactive waste category of the target after full operation time is of crucial importance. The results obtained from a small survey among project partners of 7th Framework Program granted by EU 202247 contract have been used. Waste characteristics of different potential spallation target materials were compared. Based on waste index, the tungsten target is the best alternative and the second one is the mercury target. However, all alternatives have HLW category after a 10 year cooling. Based on heat generation alone all of the options would be below the HLW limit after this cooling period. The LBE is the least advantageous alternative based on waste index and heat generation comparison. These results can be useful in compiling the licensing documents of the ESS facility as the target alternatives can be compared from various aspects related to their disposal.

  17. Measurement and analysis of turbulent liquid metal flow in a high-power spallation neutron source-EURISOL

    CERN Document Server

    Samec, K; Blumenfeld, L; Kharoua, C; Dementjevs, S; Milenkovic, R Z

    2011-01-01

    The European Isotope Separation On-Line (EURISOL) design study completed in 2009 examined means of producing exotic nuclei for fundamental research. One of the critical components identified in the study was a high-power neutron spallation source in which a target material is impacted by a proton beam producing neutrons by a process known as spallation. Due to the high heat power deposition, liquid metal, in this case mercury, is the only viable choice as target material. Complex issues arise from the use of liquid metal. It is characterised by an unusually low Prandtl number and a higher thermal expansivity than conventional fluids. The turbulence structure in LM is thereby affected and still an object of intense research, hampered in part by measurement difficulties. The use of Computational Fluid Dynamics (CFD) allowed a satisfactory design for the neutron source to be found rapidly with little iteration. However it was feared that the development of the boundary layer and associated turbulence would not b...

  18. Topical report on a preconceptual design for the Spallation-Induced Lithium Conversion (SILC) target for the accelerator production of tritium (APT)

    Energy Technology Data Exchange (ETDEWEB)

    Van Tuyle, G.J.; Cokinos, D.M.; Czajkowski, C.; Franz, E.M.; Kroeger, P.; Todosow, M.; Youngblood, R.; Zucker, M.

    1993-09-30

    The preconceptual design of the APT Li-Al target system, also referred to as the Spallation-Induced Lithium Conversion (SILC), target system, is summarized in this report. The system has been designed to produce a ``3/8 Goal`` quantity of tritium using the 200-mA, 1.0 GeV proton beam emerging from the LANL-designed LINAC. The SILC target system consists of a beam expander, a heavy-water-cooled lead spallation neutron source assembly surrounded by light-water-cooled Li-Al blankets, a target window, heat removal systems, and related safety systems. The preconceptual design of each of these major components is described. Descriptions are also provided for the target fabrication, tritium extraction, and waste-steam processes. Performance characteristics are presented and discussed.

  19. Spallation as a dominant source of pusher-fuel and hot-spot mix in inertial confinement fusion capsules

    Science.gov (United States)

    Orth, Charles D.

    2016-02-01

    We suggest that a potentially dominant but previously neglected source of pusher-fuel and hot-spot "mix" may have been the main degradation mechanism for fusion energy yields of modern inertial confinement fusion (ICF) capsules designed and fielded to achieve high yields—not hydrodynamic instabilities. This potentially dominant mix source is the spallation of small chunks or "grains" of pusher material into the fuel regions whenever (1) the solid material adjacent to the fuel changes its phase by nucleation and (2) this solid material spalls under shock loading and sudden decompression. We describe this mix mechanism, support it with simulations and experimental evidence, and explain how to eliminate it and thereby allow higher yields for ICF capsules and possibly ignition at the National Ignition Facility.

  20. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jaksch, S. [ESS Design Update Programme – Germany, Forschungszentrum Jülich GmbH, Jülich (Germany); Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching (Germany); Martin-Rodriguez, D. [ESS Design Update Programme – Germany, Forschungszentrum Jülich GmbH, Jülich (Germany); Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching (Germany); Neutron Optics and Shielding Group, European Spallation Source AB, Lund (Sweden); Ostermann, A. [Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) at Heinz Maier-Leibnitz Zentrum, Technische Universität Muünchen, Garching (Germany); Jestin, J. [Laboratoire Léon Brillouin, LLB, CEA—Saclay, Gif sur Yvette cedex (France); Duarte Pinto, S.; Bouwman, W.G. [Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands); Uher, J. [Amsterdam Scientific Instruments, Amsterdam (Netherlands); Engels, R. [Zentralinstitut für Elektronik (ZEA-2), Forschungszentrum Jülich GmbH, Jülich (Germany); Frielinghaus, H. [ESS Design Update Programme – Germany, Forschungszentrum Jülich GmbH, Jülich (Germany); Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Garching (Germany)

    2014-10-21

    A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards µm and tens of µm, respectively. Two 1 m{sup 2} area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.

  2. Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, A.; Makela, M.; Bagdasarova, Y.; Boissevain, J.; Bowles, T. J.; Currie, S. A.; Hill, R. E.; Hogan, G.; Morris, C. L.; Mortensen, R. N.; Ramsey, J.; Seestrom, S. J.; Sondheim, W. E.; Teasdale, W.; Wang, Z. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Back, H. O.; Broussard, L. J.; Hoagland, J.; Holley, A. T.; Pattie, R. W. Jr. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); and others

    2013-01-15

    In this paper, we describe the performance of the Los Alamos spallation-driven solid-deuterium ultra-cold neutron (UCN) source. Measurements of the cold neutron flux, the very low energy neutron production rate, and the UCN rates and density at the exit from the biological shield are presented and compared to Monte Carlo predictions. The cold neutron rates compare well with predictions from the Monte Carlo code MCNPX and the UCN rates agree with our custom UCN Monte Carlo code. The source is shown to perform as modeled. The maximum delivered UCN density at the exit from the biological shield is 52(9) UCN/cc with a solid deuterium volume of {approx}1500 cm{sup 3}.

  3. 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.

  4. Standard Practice for Conducting Irradiations at Accelerator-Based Neutron Sources

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1996-01-01

    1.1 This practice covers procedures for irradiations at accelerator-based neutron sources. The discussion focuses on two types of sources, namely nearly monoenergetic 14-MeV neutrons from the deuterium-tritium T(d,n) interaction, and broad spectrum neutrons from stopping deuterium beams in thick beryllium or lithium targets. However, most of the recommendations also apply to other types of accelerator-based sources, including spallation neutron sources (1). Interest in spallation sources has increased recently due to their proposed use for transmutation of fission reactor waste (2). 1.2 Many of the experiments conducted using such neutron sources are intended to simulate irradiation in another neutron spectrum, for example, that from a DT fusion reaction. The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. In general, the intent of these simulations is to establish the fundam...

  5. 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

  6. Accelerator driven neutron sources in Korea. Current and future

    International Nuclear Information System (INIS)

    Lee, Young-Ouk; Oh, Byung-Hoon; Hong, Bong-Geun; Chang, Jonghwa; Chang, Moon-Hee; Kim, Guinyun; Kim, Gi-Donng; Choi, Byung-Ho

    2008-01-01

    The Pohang Neutron Facility, based on a 65 MeV electron linear accelerator, has a neutron-gamma separation circuit, water-moderated tantalum target and 12 m TOF. It produces pulsed photonuclear neutrons with ≅2 μs width, 50 mA peak current and 15 Hz repetition, mainly for the neutron nuclear data production in up to keV energies. The Tandem Van de Graff at Korea Institute of Geoscience and Mineral Resources (KIGAM) is dedicated to measure MeV energy neutron capture and total cross section using TOF and prompt gamma ray detection system. The facility pulsed ≅10 8 mono-energetic neutrons/sec from 3 H(p,n) reaction with 1-2 ns width and 125 ns period. Korea Institute of Radiological and Medical Sciences (KIRAMS) has the MC50 medical cyclotron which accelerates protons up to an energy of 45 MeV and has several beam ports for proton or neutron irradiations. Beam current can be controlled from a few nano amperes to 50 uA. Korea Atomic Energy Research Institute (KAERI) has a plan to develop a neutron source by using 20 MeV electron accelerator. This photo-neutron source will be mainly used for nuclear data measurements based on time-of-flight experiments. A high intensity fast neutron source is also proposed to respond growing demands of fast neutrons, especially for the fusion material test. Throughput will be as high as several 10 13 neutrons/sec from D-T reaction powered by a high current (200 mA) ion source, a drive-in target and cooling systems, and closed circuit tritium ventilation/recovery systems. The Proton Engineering Frontier Project (PEFP) is developing a 100 MeV, 20 mA pulsed proton linear accelerator equipped with 5 target rooms, one of which is dedicated to produce neutrons using tungsten target. PEFP also proposes the 1-2 GeV rapid cycling synchrotron accelerator as an extension of the PEFP linac, which can be used for nuclear and high energy physics experiment, spallation neutron source, radioisotope, medical research, etc. (author)

  7. Optimization by simulation of the coupling between a sub-critical reactor and its spallation source. Towards a pilot reactor; Optimisation par simulation du couplage entre un reacteur sous-critique et sa source de spallation. Application a un demonstrateur

    Energy Technology Data Exchange (ETDEWEB)

    Kerdraon, D

    2001-10-01

    Accelerator Driven Systems (ADS), based on a proton accelerator and a sub-critical core coupled with a spallation target, offer advantages in order to reduce the nuclear waste radiotoxicity before repository closure. Many studies carried out on the ADS should lead to the definition of an experimental plan which would federate the different works in progress. This thesis deals with the neutronic Monte Carlo simulations with the MCNPX code to optimize such a system in view of a pilot reactor building. First, we have recalled the main neutronic properties of an hybrid reactor. The concept of gas-cooled eXperimental Accelerator Driven System (XADS) chosen for our investigations comes from the preliminary studies done by the Framatome company. In order to transmute minor actinides, we have considered the time evolution of the main fuels which could be reasonably used for the demonstration phases. The neutronic parameters of the reactor, concerning minor actinide transmutation, are reported. Also, we have calculated the characteristic times and the transmutation rates in the case of {sup 99}Tc and {sup 129}I isotopes. We have identified some neutronic differences between an experimental and a power ADS according to the infinite multiplication coefficient, the shape factor and the level of flux to extend the demonstrator concept. We have proposed geometric solutions to keep the radial shape factor of a power ADS acceptable. In the last part, beyond the experimental XADS scope, we have examined the possible transition towards an uranium/thorium cycle based on Molten Salt Reactors using a power ADS in order to generate the required {sup 233}U proportion. (author)

  8. European Neutrons form Parasitic Research to Global Strategy: Realizing Plans for a Transnational European Spallation Source in the Wake of the Cold War

    Science.gov (United States)

    Kaiserfeld, Thomas

    2016-03-01

    Studies of Big Science have early on focused on instrumentation and scientific co-operation in large organizations, later on to take into account symbolic values and specific research styles while more recently also involving the relevance of commercial interests and economic development as well as the assimilation of research traditions. In accordance with these transformed practices, this presentation will analyze how an organization with the purpose of realizing a Big-Science facility, The European Spallation Source, has successfully managed to present the project as relevant to different national and international policy-makers, to the community of European neutron researchers as well as to different industrial interests. All this has been achieved in a research-policy environment, which has been the subject to drastic transformations, from calls to engage researchers from the former eastern bloc in the early 1990s via competition with American and Asian researchers at the turn of the century 2000 to intensified demands on business applications. During this process, there has also been fierce competition between different potential sites in the U.K., Germany, Spain, Hungary and Sweden, not once, but twice. The project has in addition been plagued by withdrawals of key actors as well as challenging problems in the field of spallation-source construction. Nevertheless, the European Spallation Source has survived from the early 1990s until today, now initiating the construction process at Lund in southern Sweden. In this presentation, the different measures taken and arguments raised by the European Spallation Source project in order to realize the facility will be analysed. Especially the different designs of the European Spallation Source will be analysed as responses to external demands and threats.

  9. Accelerator x-ray sources

    CERN Document Server

    Talman, Richard

    2007-01-01

    This first book to cover in-depth the generation of x-rays in particle accelerators focuses on electron beams produced by means of the novel Energy Recovery Linac (ERL) technology. The resulting highly brilliant x-rays are at the centre of this monograph, which continues where other books on the market stop. Written primarily for general, high energy and radiation physicists, the systematic treatment adopted by the work makes it equally suitable as an advanced textbook for young researchers.

  10. Optimization by simulation of the coupling between a sub-critical reactor and its spallation source. Towards a pilot reactor

    International Nuclear Information System (INIS)

    Kerdraon, D.

    2001-10-01

    Accelerator Driven Systems (ADS), based on a proton accelerator and a sub-critical core coupled with a spallation target, offer advantages in order to reduce the nuclear waste radiotoxicity before repository closure. Many studies carried out on the ADS should lead to the definition of an experimental plan which would federate the different works in progress. This thesis deals with the neutronic Monte Carlo simulations with the MCNPX code to optimize such a system in view of a pilot reactor building. First, we have recalled the main neutronic properties of an hybrid reactor. The concept of gas-cooled eXperimental Accelerator Driven System (XADS) chosen for our investigations comes from the preliminary studies done by the Framatome company. In order to transmute minor actinides, we have considered the time evolution of the main fuels which could be reasonably used for the demonstration phases. The neutronic parameters of the reactor, concerning minor actinide transmutation, are reported. Also, we have calculated the characteristic times and the transmutation rates in the case of 99 Tc and 129 I isotopes. We have identified some neutronic differences between an experimental and a power ADS according to the infinite multiplication coefficient, the shape factor and the level of flux to extend the demonstrator concept. We have proposed geometric solutions to keep the radial shape factor of a power ADS acceptable. In the last part, beyond the experimental XADS scope, we have examined the possible transition towards an uranium/thorium cycle based on Molten Salt Reactors using a power ADS in order to generate the required 233 U proportion. (author)

  11. Potential containment materials for liquid-lead and lead-bismuth eutectic spallation neutron source

    International Nuclear Information System (INIS)

    Park, J.J.; Butt, D.P.; Beard, C.A.

    1997-11-01

    Lead (Pb) and lead-bismuth eutectic (44Pb-56Bi) have been the two primary candidate liquid-metal target materials for the production of spallation neutrons. Selection of a container material for the liquid-metal target will greatly affect the lifetime and safety of the target subsystem. For the lead target, niobium-1 (wt%) zirconium (Nb-1Zr) is a candidate containment material for liquid lead, but its poor oxidation resistance has been a major concern. The oxidation rate of Nb-1Zr was studied based on the calculations of thickness loss due to oxidation. According to these calculations, it appeared that uncoated Nb-1Zr may be used for a one-year operation at 900 C at P O 2 = 1 x 10 -6 torr, but the same material may not be used in argon with 5-ppm oxygen. Coating technologies to reduce the oxidation of Nb-1Zr are reviewed, as are other candidate refractory metals such as molybdenum, tantalum, and tungsten. For the Pb-Bi target, three candidate containment materials are suggested based on a literature survey of the materials compatibility and proton irradiation tests: Croloy 2-1/4, modified 9Cr-1Mo, and 12Cr-1Mo (HT-9) steel. These materials seem to be used only if the lead-bismuth is thoroughly deoxidized and treated with zirconium and magnesium

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  13. Negative ion sources for tandem accelerator

    International Nuclear Information System (INIS)

    Minehara, Eisuke

    1980-08-01

    Four kinds of negative ion sources (direct extraction Duoplasmatron ion source, radial extraction Penniing ion source, lithium charge exchange ion source and Middleton-type sputter ion source) have been installed in the JAERI tandem accelerator. The ion sources can generate many negative ions ranging from Hydrogen to Uranium with the exception of Ne, Ar, Kr, Xe and Rn. Discussions presented in this report include mechanisms of negative ion formation, electron affinity and stability of negative ions, performance of the ion sources and materials used for negative ion production. Finally, the author will discuss difficult problems to be overcome in order to get any negative ion sufficiently. (author)

  14. 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.

  15. 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...

  16. Spallation reactions

    International Nuclear Information System (INIS)

    Cugon, J.

    1996-01-01

    Spallation reactions dominate the interactions of hadrons with nuclei in the GeV range (from ∼ 0.1 to ∼ 10 GeV). They correspond to a sometimes important ejection of light particles leaving most of the time a residue of mass commensurate with the target mass. The main features of the experimental data are briefly reviewed. The most successful theoretical model, namely the intranuclear cascade + evaporation model, is presented. Its physical content, results and possible improvements are critically discussed. Alternative approaches are shortly reviewed. (author)

  17. 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.

  18. 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

  19. 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. Of the 12, only 3 isotopes showed any potential to exceed the U.S. Nuclear Regulatory Commission (NRC) 10 Code of Federal Regulations (CFR) Part 20 Drinking Water Limits (DWLs). These isotopes were 14C, 22Na, and 54Mn. The latter two activation products have very short half-lives of 2.6 years and 0.854 year, respectively. Therefore, these will decay before reaching an off-site receptor, and they cannot pose off-site hazards. However, for this extremely conservative model, which overestimates the mobility of the contaminant, 14C, which has a 5,730-year half-life, was shown to represent a potential concern in the context of this study's conservative assumptions. This study examines alternative modifications to the SNS shield berm and makes recommendations.

  20. Application of new radiation detection techniques at the Paul Scherrer Institut, especially at the spallation neutron source

    International Nuclear Information System (INIS)

    Lehmann, E.; Pleinert, H.; Williams, T.; Pralong, C.

    1999-01-01

    The demands on modern irradiation detection systems are diverse, encompassing spatial resolution, dynamic range, sensitivity and reproducibility. Nevertheless, there are two important new methods which can satisfy most of these demands in several applications: camera based systems and imaging plates. Imaging plates have primarily been used as γ- and β-sensitive detectors in biology and medicine, but are now available also as neutron sensitive systems. These methods are ideally suited for applications in neutron radiography because of their high sensitivity, linearity and digital output. Image processing, quantification of the image data and automated pattern recognition can easily be performed using modern software tools. The imaging plate system at PSI is shared between groups in reactor physics, radiation protection, biology, proton therapy and nuclear medicine. The collected experience from these different interests establishes the basis for a most effective application of this technique. The utilisation of detector systems based on CCD-cameras have other advantages, like low acquisition time, high frame rates, reproducibility as well as high dynamic range. These detectors are applied to investigations of time dependent processes, distribution analyses and quantitative studies. The new radiography facility NEUTRA at the spallation source SINQ provides excellent conditions for neutron radiography studies. Some first examples of investigations with imaging plates and the CCD-camera system are given

  1. 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.

  2. Negative hydrogen ion sources for accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Moehs, D.P.; /Fermilab; Peters, J.; /DESY; Sherman, J.; /Los Alamos

    2005-08-01

    A variety of H{sup -} ion sources are in use at accelerator laboratories around the world. A list of these ion sources includes surface plasma sources with magnetron, Penning and surface converter geometries as well as magnetic-multipole volume sources with and without cesium. Just as varied is the means of igniting and maintaining magnetically confined plasmas. Hot and cold cathodes, radio frequency, and microwave power are all in use, as well as electron tandem source ignition. The extraction systems of accelerator H{sup -} ion sources are highly specialized utilizing magnetic and electric fields in their low energy beam transport systems to produce direct current, as well as pulsed and/or chopped beams with a variety of time structures. Within this paper, specific ion sources utilized at accelerator laboratories shall be reviewed along with the physics of surface and volume H{sup -} production in regard to source emittance. Current research trends including aperture modeling, thermal modeling, surface conditioning, and laser diagnostics will also be discussed.

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

    Science.gov (United States)

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

    2016-01-01

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

  4. 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 ...

  5. Livermore Accelerator Source for Radionuclide Science (LASRS)

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Scott [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bleuel, Darren [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johnson, Micah [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rusnak, Brian [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soltz, Ron [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tonchev, Anton [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-05

    The Livermore Accelerator Source for Radionuclide Science (LASRS) will generate intense photon and neutron beams to address important gaps in the study of radionuclide science that directly impact Stockpile Stewardship, Nuclear Forensics, and Nuclear Material Detection. The co-location of MeV-scale neutral and photon sources with radiochemical analytics provides a unique facility to meet current and future challenges in nuclear security and nuclear science.

  6. Particle accelerators and lasers high energy sources

    International Nuclear Information System (INIS)

    Watteau, J.P.

    1985-04-01

    Particle accelerators and lasers are to-day precious devices for physicist and engineer. Their performance and scope do not stop growing. Producing thin beams of high energy particles or photons, they are able to be very high energy sources which interact strongly with matter. Numerous applications use them: research, industry, communication, medicine, agroalimentary, defence, and soon. In this note, their operation principles are described and some examples of their use as high energy sources are given [fr

  7. High gradient accelerators for linear light sources

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, W.A.

    1988-09-26

    Ultra-high gradient radio frequency linacs powered by relativistic klystrons appear to be able to provide compact sources of radiation at XUV and soft x-ray wavelengths with a duration of 1 picosecond or less. This paper provides a tutorial review of the physics applicable to scaling the present experience of the accelerator community to the regime applicable to compact linear light sources. 22 refs., 11 figs., 21 tabs.

  8. Accelerators for energy

    International Nuclear Information System (INIS)

    Inoue, Makoto

    2000-01-01

    A particle accelerator is a device to consume energy but not to produce it. Then, the titled accelerator seems to mean an accelerator for using devices related to nuclear energy. For an accelerator combined to nuclear fissionable fuel, neutron sources are D-T type, (gamma, n) reaction using electron beam type spallation type, and so forth. At viewpoints of powers of incident beam and formed neutron, a spallation type source using high energy proton is told to be effective but others have some advantages by investigation on easy operability, easy construction, combustion with target, energy and directivity of neutron, and so forth. Here were discussed on an accelerator for research on accelerator driven energy system by dividing its researching steps, and on kind, energy, beam intensity, and so forth of an accelerator suitable for it. And, space electric charge effect at beam propagation direction controlled by beam intensity of cyclotron was also commented. (G.K.)

  9. Accelerator-driven X-ray Sources

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-09

    After an introduction which mentions x-ray tubes and storage rings and gives a brief review of special relativity, the subject is treated under the following topics and subtopics: synchrotron radiation (bending magnet radiation, wiggler radiation, undulator radiation, brightness and brilliance definition, synchrotron radiation facilities), x-ray free-electron lasers (linac-driven X-ray FEL, FEL interactions, self-amplified spontaneous emission (SASE), SASE self-seeding, fourth-generation light source facilities), and other X-ray sources (energy recovery linacs, Inverse Compton scattering, laser wakefield accelerator driven X-ray sources. In summary, accelerator-based light sources cover the entire electromagnetic spectrum. Synchrotron radiation (bending magnet, wiggler and undulator radiation) has unique properties that can be tailored to the users’ needs: bending magnet and wiggler radiation is broadband, undulator radiation has narrow spectral lines. X-ray FELs are the brightest coherent X-ray sources with high photon flux, femtosecond pulses, full transverse coherence, partial temporal coherence (SASE), and narrow spectral lines with seeding techniques. New developments in electron accelerators and radiation production can potentially lead to more compact sources of coherent X-rays.

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

    International Nuclear Information System (INIS)

    Mauro, N. A.; Vogt, A. J.; Derendorf, K. S.; Johnson, M. L.; Kelton, K. F.; Rustan, G. E.; Quirinale, D. G.; Goldman, A. I.; Kreyssig, A.; Lokshin, K. A.; Neuefeind, J. C.; An, Ke; Wang, Xun-Li; Egami, T.

    2016-01-01

    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 64 Ni 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)

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

    Science.gov (United States)

    Mauro, N A; Vogt, A J; Derendorf, K S; Johnson, M L; Rustan, G E; Quirinale, D G; Kreyssig, A; Lokshin, K A; Neuefeind, J C; An, Ke; Wang, Xun-Li; Goldman, A I; Egami, T; Kelton, K F

    2016-01-01

    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 Zr64Ni36 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).

  12. Inelastic scattering research at a 1 MW long pulse spallation neutron source

    International Nuclear Information System (INIS)

    Carlile, C.J.

    1995-01-01

    The brief was, with respect to the LPSS bench mark design supplied (60 Hz, 1 MW, Imsec proton pulse, with a split, non-fissile target and 4 moderators in a flux trap geometry design), to identify a set of instruments, and to assess their performance with respect to existing spectrometers on other sources. Any modifications to the existing instruments which would make them more effective on the bench-mark source, or conversely, any modifications to the source bench-mark required by the proposed instruments were to be identified, as were any uncertainties in the estimated performances, or any R ampersand D needed to make the proposed instruments viable. Any new instrument concepts specifically matched to the long pulse itself were to be identified and assessed. This process was to result in an indicative list of instruments for the source. A figure of around 10 spectrometers was to be aimed for

  13. Corrosion mechanism of T91 steel by Pb-Bi eutectic used as spallation target: importance for accelerator driven system

    International Nuclear Information System (INIS)

    Martinelli, L.

    2005-10-01

    The aim of this work has been to determine the oxidation mechanism of the martensitic steel T91 in the Pb-Bi liquid eutectic alloy, saturated in oxygen, at 470 C, in order to develop a long-term predictive model of the oxidation kinetics of the steel. This work enters in the framework of the lifetime studies of the spallation module demonstrator: MEGAPIE for the researches on hybrid reactors. An experimental characterization of the oxide layers has been carried out as well as the oxidation kinetics of the T91 steel. An oxidation mechanism has been elaborated from these experimental results and then simulated. The oxide layer formed at the T91 surface presents a duplex structure constituted by a magnetite external layer and a spinel Fe-Cr internal layer. A growth mechanism of the oxide layers has been proposed: the growth of the magnetite layer seems to be limited by the iron diffusion in the lattice of the duplex oxide layer. In parallel, an auto-regulation mechanism seems to govern the growth of the Fe-Cr spinel layer. This mechanism includes a non-limiting step of the oxygen diffusion in the oxide layer (by liquid way in the nano-channels of lead), as well as a limiting step of iron diffusion in the lattice of the oxide layer. In considering the proposed oxidation mechanisms, a simulation of the growth of the two oxide layers is carried out and compared to the long-time oxidation growth kinetics. The good agreement between the experimental results allows, finally, to strengthen the proposition of a long-term growth kinetic oxidation mechanism of the oxide layers. (O.M.)

  14. Ion sources for high-frequency accelerators

    International Nuclear Information System (INIS)

    Keller, R.

    1985-01-01

    Ion sources are being applied increasingly in many areas of physics and technology, from basic research in nuclear and atomic physics to energy research, isotope separation, implanation technology, surface processing and analysis all the way to biomedicine. It is impossible within the framework of this discussion to provide a comprehensive survey of the variety of avialable source types. The function and problems of the types important for high-frequency accelerators are to be explained using a few individual examples in order to stimulate a basic understanding for this technically sophisticated and little-known equipment. The sources discussed here supply singly or multiply charged, positive ions. 54 refs., 18 figs

  15. $^{206}$ Po sources for production and release studies relevant for high power spallation targets

    CERN Multimedia

    The knowledge of the evaporation behaviour of Po is of essential importance for several scientific and technological applications, like accelerator driven systems (ADS) or the LIEBE project at CERN-ISOLDE. Fundamental investigations on the experimental conditions for the formation of volatile Po species as well as on the chemical composition of the volatile compounds are necessary for a safe operation of such facilities. $^{206}$Po, a mainly $\\gamma$- ray-emitting Po isotope with a half-life of 8.8 d, is best suited for model studies, due to the lower radiation hazard compared to the longer-lived $\\alpha$-emitting isotopes $^{208-210}$Po as well as the easy-to-measure $\\gamma$-ray emission. We propose the production of $^{206}$Po samples in several matrices via the implantation of its precursor $^{210}$Fr into selected metal foils at CERN-ISOLDE. Using these samples, experiments will be carried out at PSI studying the volatilization of Po from different matrices under varying chemical conditions.

  16. Preliminary evaluation of cavitation-erosion resistance of Ti-alloys in mercury for the Spallation Neutron Source

    International Nuclear Information System (INIS)

    Pawel, S.J.; Mansur, L.K.

    2010-01-01

    A number of Ti-based alloys in both the mill-annealed and 20% cold-worked conditions were subjected to sonication conditions in Hg using a vibratory horn to assess relative cavitation-erosion resistance. Weight loss as a function of exposure time decreased monotonically with increasing hardness for all alloys/conditions examined, with Ti-6Al-4V (Grade 5) and Ti-6Al-2Sn-4Zr-2Mo yielding the best resistance to cavitation-erosion as evidenced by low weight losses and little or no tendency to form pits on the exposed surface. Unalloyed Ti (Grade 4) and Ti-0.12Pd (Grade 7) exhibited greater weight losses by a factor of about two and about five, respectively, with Ti-0.12Pd particularly prone to pitting development. The mean erosion rates of the best two Ti-alloys examined were about a factor of three higher than identically tested 316LN stainless steel following a low temperature carburizing treatment, but this difference is considered minor given that the rate for both materials is very low/manageable and represents a through-thickness property for the Ti-alloys. A nitriding surface treatment was also evaluated as a potential method to further increase the cavitation-erosion resistance of these alloys in Hg, but the selected treatment proved largely ineffective as measured by rapid weight loss. Recommendations for further work to evaluate the efficacy of Ti-based alloys for use in high-powered targets for the Spallation Neutron Source are given.

  17. The test beamline of the European Spallation Source - Instrumentation development and wavelength frame multiplication

    DEFF Research Database (Denmark)

    Woracek, R.; Hofmann, T.; Bulat, M.

    2016-01-01

    which, in contrast, are all providing short neutron pulses. In order to enable the development of methods and technology adapted to this novel type of source well in advance of the first instruments being constructed at ESS, a test beamline (TBL) was designed and built at the BER II research reactor...... wavelength band between 1.6 A and 10 A by a dedicated wavelength frame multiplication (WFM) chopper system. WFM is proposed for several ESS instruments to allow for flexible time-of-flight resolution. Hence, ESS will benefit from the TBL which offers unique possibilities for testing methods and components...

  18. An Accelerator Neutron Source for BNCT

    International Nuclear Information System (INIS)

    Blue, Thomas E.

    2006-01-01

    The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were (1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, (2) that the patient treatment time be reasonable, (3) that the proton current required to treat patients in reasonable times be technologically achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally (4) that the treatment be safe for the patients

  19. An Accelerator Neutron Source for BNCT

    Energy Technology Data Exchange (ETDEWEB)

    Blue, Thomas, E

    2006-03-14

    The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.

  20. CAS Accelerator Physics (Ion Sources) in Slovakia

    CERN Multimedia

    CAS School

    2012-01-01

    The CERN Accelerator School (CAS) and the Slovak University of Technology jointly organised a specialised course on ion sources, held at the Hotel Senec, Senec, Slovakia, from 29 May to 8 June, 2012.   Following some background lectures on accelerator physics and the fundamental processes of atomic and plasma physics, the course covered a wide range of topics related to ion sources and highlighted the latest developments in the field. Realistic case studies and topical seminars completed the programme. The school was very successful, with 69 participants representing 25 nationalities. Feedback from the participants was extremely positive, reflecting the high standard of the lectures. The case studies were performed with great enthusiasm and produced some excellent results. In addition to the academic programme, the participants were able to take part in a one-day excursion consisting of a guided tour of Bratislava and free time. A welcome event was held at the Hotel Senec, with s...

  1. Acceleration of Automated HI Source Extraction

    Science.gov (United States)

    Badenhorst, S. J.; Blyth, S.; Kuttel, M. M.

    2013-10-01

    We aim to enable fast automated extraction of neutral hydrogen (HI) sources from large survey data sets. This requires both handling the large files (>5 TB) to be produced by next-generation interferometers and acceleration of the source extraction algorithm. We develop an efficient multithreaded implementation of the A'Trous wavelet reconstruction algorithm, which we evaluate against the serial implementation in the DUCHAMP package. We also evaluate three memory management libraries (Mmap, Boost and Stxxl) that enable processing of data files too large to fit into main memory, to establish which provides the best performance.

  2. 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.

  3. A compact time-of-flight SANS instrument optimised for measurements of small sample volumes at the European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Kynde, Søren, E-mail: kynde@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen (Denmark); Hewitt Klenø, Kaspar [Niels Bohr Institute, University of Copenhagen (Denmark); Nagy, Gergely [SINQ, Paul Scherrer Institute (Switzerland); Mortensen, Kell; Lefmann, Kim [Niels Bohr Institute, University of Copenhagen (Denmark); Kohlbrecher, Joachim, E-mail: Joachim.kohlbrecher@psi.ch [SINQ, Paul Scherrer Institute (Switzerland); Arleth, Lise, E-mail: arleth@nbi.ku.dk [Niels Bohr Institute, University of Copenhagen (Denmark)

    2014-11-11

    The high flux at European Spallation Source (ESS) will allow for performing experiments with relatively small beam-sizes while maintaining a high intensity of the incoming beam. The pulsed nature of the source makes the facility optimal for time-of-flight small-angle neutron scattering (ToF-SANS). We find that a relatively compact SANS instrument becomes the optimal choice in order to obtain the widest possible q-range in a single setting and the best possible exploitation of the neutrons in each pulse and hence obtaining the highest possible flux at the sample position. The instrument proposed in the present article is optimised for performing fast measurements of small scattering volumes, typically down to 2×2×2 mm{sup 3}, while covering a broad q-range from about 0.005 1/Å to 0.5 1/Å in a single instrument setting. This q-range corresponds to that available at a typical good BioSAXS instrument and is relevant for a wide set of biomacromolecular samples. A central advantage of covering the whole q-range in a single setting is that each sample has to be loaded only once. This makes it convenient to use the fully automated high-throughput flow-through sample changers commonly applied at modern synchrotron BioSAXS-facilities. The central drawback of choosing a very compact instrument is that the resolution in terms of δλ/λ obtained with the short wavelength neutrons becomes worse than what is usually the standard at state-of-the-art SANS instruments. Our McStas based simulations of the instrument performance for a set of characteristic biomacromolecular samples show that the resulting smearing effects still have relatively minor effects on the obtained data and can be compensated for in the data analysis. However, in cases where a better resolution is required in combination with the large simultaneous q-range characteristic of the instrument, we show that this can be obtained by inserting a set of choppers.

  4. 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)

  5. Nuclear weapon relevant materials and preventive arms control. Uranium-free fuels for plutonium elimination and spallation neutron sources

    International Nuclear Information System (INIS)

    Liebert, Wolfgang; Englert, Matthias; Pistner, Christoph

    2009-01-01

    technological challenges of nuclear non-proliferation, which are directly connected with the central role of weapon-relevant materials, and it is trying to present practical solutions on a technical basis: - Discover paths for the disposal of existing amounts of nuclear weapon-relevant materials elaborating on the example of technically-based plutonium disposal options: central technical questions of the possible use of uranium-free inert matrix fuel (IMF) in currently used light water reactors will be addressed in order to clarify which advantages or disadvantages do exist in comparison to other disposal options. The investigation is limited on the comparison with one other reactor-based option, the use of uranium-plutonium mixed-oxide (MOX) fuels. - Analysis of proliferation relevant potentials of new nuclear technologies (accessibility of weapon materials): Exemplary investigation of spallation neutron sources in order to improve this technology by a more proliferation resistant shaping. Although they are obviously capable to breed nuclear weapon-relevant materials like plutonium, uranium-233 or tritium, there is no comprehensive analysis of nonproliferation aspects of spallation neutron sources up to now. Both project parts provide not only contributions to the concept of preventive arms control but also to the shaping of technologies, which is oriented towards the criteria of proliferation resistance.

  6. 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)

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

    International Nuclear Information System (INIS)

    Sommer, W.F.

    1995-12-01

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

  8. QGSM development for spallation reactions modeling

    Directory of Open Access Journals (Sweden)

    Gudima K.K.

    2012-12-01

    Full Text Available The growing interest in spallation neutron sources, accelerator-driven systems, R&D of rare isotope beams, and development of external beam radiation therapy necessitated the improvement of nuclear reaction models for both stand-alone codes for the analysis of nuclear reactions and event generators within the Monte Carlo transport systems for calculations of interactions of high-energy particles with matter in a wide range of energy and in arbitrary 3D geometry of multicomponent targets. The exclusive approach to the description of nuclear reactions is the most effective for detailed calculation of inelastic interactions with atomic nuclei. It provides the correct description of particle production, single- and double-differential spectra, recoil, and fission product yields. This approach has been realized in the Quark Gluon String Model (QGSM for nuclear reactions induced by photons, hadrons, and high energy heavy ions. In this article, improved versions of the QGSM model and a corresponding code have been developed tested and bench marked against experimental data for neutron production in spallation reactions on thin and thick targets in the energy range from a few MeV to several GeV/nucleon.

  9. QGSM development for spallation reactions modeling

    Science.gov (United States)

    Baznat, M. I.; Chigrinov, S. E.; Gudima, K. K.

    2012-12-01

    The growing interest in spallation neutron sources, accelerator-driven systems, R&D of rare isotope beams, and development of external beam radiation therapy necessitated the improvement of nuclear reaction models for both stand-alone codes for the analysis of nuclear reactions and event generators within the Monte Carlo transport systems for calculations of interactions of high-energy particles with matter in a wide range of energy and in arbitrary 3D geometry of multicomponent targets. The exclusive approach to the description of nuclear reactions is the most effective for detailed calculation of inelastic interactions with atomic nuclei. It provides the correct description of particle production, single- and double-differential spectra, recoil, and fission product yields. This approach has been realized in the Quark Gluon String Model (QGSM) for nuclear reactions induced by photons, hadrons, and high energy heavy ions. In this article, improved versions of the QGSM model and a corresponding code have been developed tested and bench marked against experimental data for neutron production in spallation reactions on thin and thick targets in the energy range from a few MeV to several GeV/nucleon.

  10. Evaluation of Importance of Source Neutrons in Accelerator-Driven System

    International Nuclear Information System (INIS)

    Kim, Yong Hee; Park, Won Seok

    2002-01-01

    An importance function of the external spallation neutrons in ADS (Accelerator-Driven System) is defined to characterize the source multiplication in subcritical blanket. For a model ADS problem, the source importance function is evaluated with the TRANSX/TWODANT code system. In order to assess the impact of the power distribution on the importance function, both homogeneous and heterogeneous cores are analyzed and corresponding source multiplications are compared. Also, based on the source importance function, an optimization of the shape of the proton current is performed from the source multiplication point of view. Additionally, the source importance function is compared with the conventional λ-mode adjoint flux, which is used as an importance function of fission neutrons in the critical reactors. Concerning an issue in the ADS design, i.e., difficulty in reducing the fission power unless the proton current is shut off, a study is performed to minimize the source importance, thereby minimizing the fission power, even when the k-eff value of the core is quite high. (authors)

  11. Heavy density liquid metal spallation target studies for Indian ADS ...

    Indian Academy of Sciences (India)

    to tens of mA) interacts with the target, which is located in the core and produces spallation neutrons (~1019/s) that diffuse into the reactor and drive the reactor. The spallation target module is the most innovative component of the ADS. It constitutes the physical interface between the accelerator and the sub-critical reactor.

  12. Accelerator Technology Division progress report, FY 1993

    International Nuclear Information System (INIS)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-01-01

    This report discusses the following topics: A Next-Generation Spallation-Neutron Source; Accelerator Performance Demonstration Facility; APEX Free-Electron Laser Project; The Ground Test Accelerator (GTA) Program; Intense Neutron Source for Materials Testing; Linac Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Radio-Frequency Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operation

  13. Proliferation Potential of Accelerator-Drive Systems: Feasibility Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Riendeau, C.D.; Moses, D.L.; Olson, A.P.

    1998-11-01

    Accelerator-driven systems for fissile materials production have been proposed and studied since the early 1950s. Recent advances in beam power levels for small accelerators have raised the possibility that such use could be feasible for a potential proliferator. The objective of this study is to review the state of technology development for accelerator-driven spallation neutron sources and subcritical reactors. Energy and power requirements were calculated for a proton accelerator-driven neutron spallation source and subcritical reactors to produce a significant amount of fissile material--plutonium.

  14. Proliferation Potential of Accelerator-Driven Systems: Feasibility Calculations

    International Nuclear Information System (INIS)

    Riendeau, C.D.; Moses, D.L.; Olson, A.P.

    1998-01-01

    Accelerator-driven systems for fissile materials production have been proposed and studied since the early 1950s. Recent advances in beam power levels for small accelerators have raised the possibility that such use could be feasible for a potential proliferator. The objective of this study is to review the state of technology development for accelerator-driven spallation neutron sources and subcritical reactors. Energy and power requirements were calculated for a proton accelerator-driven neutron spallation source and subcritical reactors to produce a significant amount of fissile material--plutonium

  15. Determination of the ¹⁴C content in activated steel components from a neutron spallation source and a nuclear power plant.

    Science.gov (United States)

    Schumann, Dorothea; Stowasser, Tanja; Volmert, Benjamin; Günther-Leopold, Ines; Linder, Hanspeter; Wieland, Erich

    2014-06-03

    The (14)C content in activated steel components from the Swiss Nuclear Power Plant (NPP) Gösgen and the Spallation Neutron Source SINQ at the Paul Scherrer Institute is determined using a wet chemistry digestion technique and liquid scintillation counting for (14)C activity measurements. The (14)C activity of an activated fuel assembly steel nut from the NPP is further compared with theoretical predictions made on the basis of a Monte Carlo reactor model for this NPP. Knowledge of the (14)C inventory in these activated steel materials is important in conjunction with future corrosion studies on these materials aimed at identifying the (14)C containing organic compounds possibly formed in the cement-based near field of a repository for radioactive waste.

  16. Feasibility and applications of the spin-echo modulation option for a small angle neutron scattering instrument at the European Spallation Source

    Science.gov (United States)

    Kusmin, A.; Bouwman, W. G.; van Well, A. A.; Pappas, C.

    2017-06-01

    We describe theoretical and practical aspects of spin-echo modulated small-angle neutron scattering (SEMSANS) as well as the potential combination with SANS. Based on the preliminary technical designs of SKADI (a SANS instrument proposed for the European Spallation Source) and a SEMSANS add-on, we assess the practicability, feasibility and scientific merit of a combined SANS and SEMSANS setup by calculating tentative SANS and SEMSANS results for soft matter, geology and advanced material samples that have been previously studied by scattering methods. We conclude that lengths from 1 nm up to 0.01 mm can be observed simultaneously in a single measurement. Thus, the combination of SANS and SEMSANS instrument is suited for the simultaneous observation of a wide range of length scales, e.g. for time-resolved studies of kinetic processes in complex multiscale systems.

  17. The CombLayer build of the MCNPX models for the design of the fast neutron ports in the European Spallation Source

    International Nuclear Information System (INIS)

    Milocco, A.; Gorini, G.; Zanini, L.; Ansell, S.

    2013-01-01

    Building MCNPX models is a time consuming process. At ISIS, a modeling architecture called 'CombLayer' has been developed, which allows MCNPX models to be produced rapidly, and in a highly parametric manner. In this work, CombLayer has been used for neutronic studies for the European Spallation Source (ESS). Initially, MCNPX models of the ESS were modified to include the irradiation ports and material test volumes. The computational time required to run each of these models was prohibitive, which precludes running multiple configurations for optimizations. To help mitigate this performance problem, we built the model using the CombLayer coding model. CombLayer is a C++ tool-kit for building geometric models. These models can then be rewritten in various formats, including MCNPX. As the CombLayer program has a working model, it is able to perform simple geometric optimizations (e.g. minimizing the cell literals, removing complementary objects) and some computed variance reduction

  18. Laser Plasma Particle Accelerators: Large Fields for Smaller Facility Sources

    Energy Technology Data Exchange (ETDEWEB)

    Geddes, Cameron G.R.; Cormier-Michel, Estelle; Esarey, Eric H.; Schroeder, Carl B.; Vay, Jean-Luc; Leemans, Wim P.; Bruhwiler, David L.; Cary, John R.; Cowan, Ben; Durant, Marc; Hamill, Paul; Messmer, Peter; Mullowney, Paul; Nieter, Chet; Paul, Kevin; Shasharina, Svetlana; Veitzer, Seth; Weber, Gunther; Rubel, Oliver; Ushizima, Daniela; Bethel, Wes; Wu, John

    2009-03-20

    Compared to conventional particle accelerators, plasmas can sustain accelerating fields that are thousands of times higher. To exploit this ability, massively parallel SciDAC particle simulations provide physical insight into the development of next-generation accelerators that use laser-driven plasma waves. These plasma-based accelerators offer a path to more compact, ultra-fast particle and radiation sources for probing the subatomic world, for studying new materials and new technologies, and for medical applications.

  19. Compact RF ion source for industrial electrostatic ion accelerator

    Science.gov (United States)

    Kwon, Hyeok-Jung; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub

    2016-02-01

    Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described.

  20. Thermal-hydraulic analysis of PDS-XADS spallation target

    International Nuclear Information System (INIS)

    Ai Nisai; Yu Jiyang; Yang Yongwei

    2012-01-01

    This paper is a study of the thermal-hydraulic analysis of PDS-XADS spallation target for the large (80 MW) core concept. PDS-XADS is a small scale experimental accelerator driven sub-critical system (ADS). The analysis presented in this paper is based on lead bismuth eutectic (LBE) cooled XADS type experimental reactors, which are the de signs of the European experimental (PDS-XADS) project. The spallation target is a very important component of accelerator driven sub-critical system (ADS) because it is responsible to keep the reactor power at the required level by spallation reactions. A high rate of neutron production by spallation reaction creates the problem of decay heat cooling. LBE flow is properly cooled, but the window is not properly cooled because of the stagnation point in the pole of the window. It would be very difficult to keep the window temperature below the design limit, which is an important design limit challenge. Thermal-hydraulic analysis of LBE spallation target has been carried out by using ANSYS CFX 11.0. The detailed CFD analysis, which reveals thermal and hydraulic conditions in the window and spallation region, is carried out for different spallation target designs. Finally, the spallation target design limit is used to choose the best design. (authors)

  1. Use of accelerator based neutron sources

    International Nuclear Information System (INIS)

    2000-05-01

    With the objective of discussing new requirements related to the use of accelerator based neutron generators an Advisory Group meeting was held in October 1998 in Vienna. This meeting was devoted to the specific field of the utilization of accelerator based neutron generators. This TECDOC reports on the technical discussions and presentations that took place at this meeting and reflects the current status of neutron generators. The 14 MeV neutron generators manufactured originally for neutron activation analysis are utilised also for nuclear structure and reaction studies, nuclear data acquisition, radiation effects and damage studies, fusion related studies, neutron radiography

  2. Spallation: understanding for predicting !?

    International Nuclear Information System (INIS)

    David, J.-C.

    2012-01-01

    This HDR report summarizes about ten years spent around spallation reaction modelling. Spallation reactions are defined as interaction of a light particle, say a nucleon, and a nucleus at an incident energy from 100 MeV up to 2-3 GeV. These reactions are divided in two steps. A first and fast phase, direct reactions also called intranuclear cascade, following by a slower phase, deexcitation of the remnant nucleus. Using the combination of INCL4, the intranuclear cascade model developed by the group, and the deexcitation code Abla from GSI, as a connecting thread, the multi-faceted spallation is presented. Chapter one deals with physics and codes, then different types of benchmarks are addressed, followed by several domains where spallation modelling plays a role, and finally, taking advantage of what has been said previously and of what can be read in the literature, new developments are suggested. (author) [fr

  3. Spallation radiation effects in materials

    International Nuclear Information System (INIS)

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

    1996-01-01

    Spallation refers to the process whereby particles (chiefly neutrons) are ejected from nuclei upon bombardment by high-energy protons. Spallation neutron sources (SNS's) use these neutrons for neutron scattering and diffraction research, and SNS's are proposed as the basis for systems for tritium production and transmutation of nuclear waste. Materials in SNS's are exposed to the incident proton beam (energies typically about 1000 MeV) and to the spallation neutrons (spectrum of energies extending up to about 1000 MeV). By contrast the fission neutrons in nuclear reactors have an average energy of only about 2 MeV, and the neutrons in fusion reactors would have energies below about 14 MeV. Furthermore, the protons and neutrons in SNS's for scattering and diffraction research are pulsed at frequencies of about 10 to 60 Hz, from which significant changes in the kinetics of point and extended defects may be expected. In addition, much higher transmutation rates occur in SNS-irradiated materials, On the whole, then, significant differences in microstructural development and macroscopic properties may result upon exposure in SNS systems, as compared with fission and fusion irradiations. In a more general sense, subjecting materials to new radiation environments has almost routinely led to new discoveries. To the extent that data are avaiable, however, the spallation environment appears to increase the degree of damage without introducing totally new effects. The first part of this presentation is an overview of radiation effects in materials, outlining essential concepts and property changes and their physical bases. This background is followed by a description of SNS irradiation environments and the effects on materials of exposure to these environments. A special discussion is given of the selection of target (e.g., liquid mercury), container (e.g., austenitic stainless steel or ferritic/martensitic steel), and structural materials in SNS systems

  4. Small accelerator-based pulsed cold neutron sources

    International Nuclear Information System (INIS)

    Lanza, Richard C.

    1997-09-01

    Small neutron sources could be used by individual researchers with the convenience of an adequate local facility. Although these sources would produce lower fluxes than the national facilities, for selected applications, the convenience and availability may overcome the limitations on source strength. Such sources might also be useful for preliminary testing of ideas before going to a larger facility. Recent developments in small, high-current pulsed accelerators makes possible such a local source for pulsed cold neutrons.

  5. 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

  6. A MCNP simulation study of neutronic calculations of spallation targets

    Directory of Open Access Journals (Sweden)

    Feghhi Seyed Amir Hossein

    2013-01-01

    Full Text Available The accelerator driven system is an innovative reactor which is being considered as a dedicated high-level waste burner. The function of the spallation target in accelerator driven system is to convert the incident high-energy particle beam to low-energy neutrons. One of the quantities of most interest for practical purposes is the number of neutrons produced per proton in a spallation target. However, this vital value depends not only on the material, but on the size of the target as well, due to the internuclear cascade. The MCNPX 2.4 code can be used for spallation target computation. Some benchmark results have been compared with MCNPX 2.4 simulations to verify the code's potential for calculating various parameters of an accelerator driven system target. Using the computation method, neutron interaction processes such as loss, capture and (n, xn into a spallation target have been studied for W, Ta, Pb, Bi, and LBE spallation targets in different target dimensions. With relative errors less than 10%, the numerical simulation provided by the MCNPX code agrees qualitatively with other simulation results previously carried out, qualifying it for spallation calculations. Among the studied targets, W and Ta targets resulted in a higher neutron spallation yield using lesser target dimensions. Pb, Bi, and LBE spallation targets behave similarly regarding the accessible leaked neutron yield on the outer surface of the spallation target. By use of a thicker target, LBE can compete with both W and Ta targets regarding the neutron yield parameter.

  7. Implementation of a low-activation Au-In-Cd decoupler into the J-PARC 1 MW short pulsed spallation neutron source

    Directory of Open Access Journals (Sweden)

    M. Teshigawara

    2018-01-01

    Full Text Available A silver-indium-cadmium (Ag-In-Cd, or AIC alloy with a 1 eV high neutron cut-off energy was originaly developed as a decoupler to provide a narrow neutron pulse width with a short tail for the J-PARC 1-MW short-pulsed spallation neutron source. As a result of later studies, gold (Au was chosen as a substitute for Ag for the production of spare decoupled moderators and reflector in order to reduce residual radioactivity thus easing handling and disposal of the spent moderator and reflector. The decoupler material Au-In-Cd (AuIC was therefore investigated and developed. To implement it into an actual moderator-reflector assembly many critical engineering issues needed to be resolved with regard to large-sized bonding between AuIC and aluminum alloy A5083 by the hot isostatic pressing process (HIP. The HIP process for AuIC and aluminum was investigated in terms of surface condition, size, and heat capacity. Implementation of an AuIC decoupler into a spare reflector assembly was successfuly achieved and will result in a remarkable reduction of radioactivity compared to AIC without sacrificing neutronic performance.

  8. Laser wakefield accelerator based light sources: potential applications and requirements

    Energy Technology Data Exchange (ETDEWEB)

    Albert, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). NIF and Photon Sciences; Thomas, A. G. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering and Radiological Sciences; Mangles, S. P.D. [Imperial College, London (United Kingdom). Blackett Lab.; Banerjee, S. [Univ. of Nebraska, Lincoln, NE (United States); Corde, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Flacco, A. [ENSTA, CNRS, Ecole Polytechnique, Palaiseau (France); Litos, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Neely, D. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL). Central Laser Facility; Viera, J. [Univ. of Lisbon (Portugal). GoLP-Inst. de Plasmas e Fusao Nuclear-Lab. Associado; Najmudin, Z. [Imperial College, London (United Kingdom). Blackett Lab.; Bingham, R. [Science and Technology Facilities Council (STFC), Oxford (United Kingdom). Rutherford Appleton Lab. (RAL). Central Laser Facility; Joshi, C. [Univ. of California, Los Angeles, CA (United States). Dept. of Electrical Engineering; Katsouleas, T. [Duke Univ., Durham, NC (United States). Platt School of Engineering

    2015-01-15

    In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose as a result of discussions held at the 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, X-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted as potential applications for laser-plasma based light sources. We discuss ongoing and future efforts to improve the properties of radiation from plasma betatron emission and Compton scattering using laser wakefield accelerators for these specific applications.

  9. 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

  10. Spallation production of neutron deficient radioisotopes in North America

    Energy Technology Data Exchange (ETDEWEB)

    Jamriska, D.J.; Peterson, E.J. [Los Alamos National Lab., NM (United States); Carty, J. [Dept. of Energy, Germantown, MD (United States). Office of Isotope Production and Distribution

    1997-12-31

    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.

  11. 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

  12. 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.

  13. Electromagnetic projectile acceleration utilizing distributed energy sources

    International Nuclear Information System (INIS)

    Parker, J.V.

    1982-01-01

    Circuit equations are derived for an electromagnetic projectile accelerator (railgun) powered by a large number of capacitive discharge circuits distributed along its length. The circuit equations are put into dimensionless form and the parameters governing the solutions derived. After specializing the equations to constant spacing between circuits, the case of lossless rails and negligible drag is analyzed to show that the electrical to kinetic energy transfer efficiency is equal to sigma/2, where sigma = 2mS/Lq 2 0 and m is the projectile mass, S the distance between discharge circuit, Lthe rail inductance per unit length, and q 0 the charge on the first stage capacitor. For sigma = 2 complete transfer of electrical to kinetic energy is predicted while for sigma>2 the projective-discharge circuit system is unstable. Numerical solutions are presented for both lossless rails and for finite rail resistance. When rail resistance is included, >70% transfer is calculated for accelerators of arbitrary length. The problem of projectile startup is considered and a simple modification of the first two stages is described which provides proper startup. Finally, the results of the numerical solutions are applied to a practical railgun design. A research railgun designed for repeated operation at 50 km/sec is described. It would have an overall length of 77 m, an electrical efficiency of 81%, a stored energy per stage of 105 kJ, and a charge transfer of <50 C per stage. A railgun of this design appears to be practicable with current pulsed power technology

  14. 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

  15. Spallation reactions studied with 4 -detector arrays

    Indian Academy of Sciences (India)

    Spallation reactions induced on heavy nuclei allow the conversion of the incident GeV proton into several tens of evaporated ... wastes and/or for developing a new type of sub-critical nuclear reactor [15,16]. This has triggered new and .... With pulsed sources, time of flight techniques become pos- sible allowing the use of ...

  16. Accelerator reliability workshop

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, L.; Duru, Ph.; Koch, J.M.; Revol, J.L.; Van Vaerenbergh, P.; Volpe, A.M.; Clugnet, K.; Dely, A.; Goodhew, D

    2002-07-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop.

  17. Accelerator reliability workshop

    International Nuclear Information System (INIS)

    Hardy, L.; Duru, Ph.; Koch, J.M.; Revol, J.L.; Van Vaerenbergh, P.; Volpe, A.M.; Clugnet, K.; Dely, A.; Goodhew, D.

    2002-01-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop

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

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  19. RF source for proton linear accelerator in Kyoto University

    International Nuclear Information System (INIS)

    Iwashita, Yoshihisa

    1987-01-01

    Construction of a 433 MHz, 7 MeV proton linear accelerator is currently underway in Kyoto University under a three-year plan starting in 1986. The ion source, power source for it, RFQ main unit, WR2100 waveguide and a set of klystrons for RFQ were installed last year, or the first year of the plan, and the power source for the klystrons for RFQ, a set of klystrons for STL, DTL main unit, etc., are planned to be installed this year. Operation has not started yet because of the absence of the power source for the klystrons. Thus this report is focused on the considerations made in selecting the acceleration frequency of 433 MHz, specifications of the klystrons and the structure of the power sources for them. Based on considerations of the efficiency and cost of the accelerating tubes and RF sources to be used, the acceleration frequencies of 433.33 MHz and 1,300 MHz were adopted. The klystron selected is Litton L5773, which has a peak power output of 1.25 Mw, average power output of 75 kW, maximum pulse width of 2,000 μS and duty of 6 percent, and it consists of four cavities. The structure and characteristics of a klystron are also described. (Nogami, K.)

  20. 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

    Megawatt pilot target experiment (MEGAPIE) is an initiative launched by Commisariat a l'Energie Atomique, Cadarache (France) and Forschungszentrum Karlsruhe (Germany) together 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

  1. 14 MV pelletron accelerator and superconducting ECR ion source

    International Nuclear Information System (INIS)

    Gupta, A.K.

    2015-01-01

    The BARC-TIFR 14UD Pelletron Accelerator at Mumbai has completed more than two and a half decade of successful operation. The accelerator is primarily used for basic research in the fields of nuclear, atomic and molecular, condensed matter physics and material science. The application areas include accelerator mass spectrometry, production of track-etch membranes, radioisotopes production, radiation damage studies and secondary neutron production for cross section measurement etc. Over the years, numerous developmental activities have been carried out in-house that have resulted in improving the overall performance and uptime of the accelerator and has also made possible to initiate variety of application oriented programmes. Since the SF 6 pressure vessels have been in operation for about 29 years, a comprehensive refurbishment and retrofitting work is carried out to comply with the safety recommendations. Recently, the beam trials were conducted with 18 GHz superconducting ECR (Electron Cyclotron Resonance) Ion Source system at Van-de-Graaff as per BARC Safety Council permission. Various ion beams with different charge states were extracted and mass analyzed and the beam quality was measured by recording their transverse emittance in situ. Experimental measurements pertaining to projectile X-rays Spectroscopy were carried out using variety of ion beams at variable energies. The superconducting Linac booster provides additional acceleration to the ions from Pelletron injector up to A ∼60 region with E∼5 MeV/A. In order to cover the entire mass range of the elements across the periodic table, an ECR based heavy ion accelerator was initiated under plan project. This heavy ion accelerator essentially comprises of a superconducting ECR ion source, room temperature RFQ (Radio Frequency Quadrupole) followed by superconducting Niobium resonators as accelerating elements. This talk will provide an overview of the developmental activities and the safety features

  2. Proceedings of the international workshop on spallation materials technology

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, L.K.; Ullmaier, H. [comps.

    1996-10-01

    This document contains papers which were presented at the International Workshop on Spallation Materials Technology. Topics included: overviews and thermal response; operational experience; materials experience; target station and component design; particle transport and damage calculations; neutron sources; and compatibility.

  3. Proceedings of the international workshop on spallation materials technology

    International Nuclear Information System (INIS)

    Mansur, L.K.; Ullmaier, H.

    1996-01-01

    This document contains papers which were presented at the International Workshop on Spallation Materials Technology. Topics included: overviews and thermal response; operational experience; materials experience; target station and component design; particle transport and damage calculations; neutron sources; and compatibility

  4. Applications of laser wakefield accelerator-based light sources

    International Nuclear Information System (INIS)

    Albert, Felicie; Thomas, Alec G. R.

    2016-01-01

    Laser-wakefield accelerators (LWFAs) were proposed more than three decades ago, and while they promise to deliver compact, high energy particle accelerators, they will also provide the scientific community with novel light sources. In a LWFA, where an intense laser pulse focused onto a plasma forms an electromagnetic wave in its wake, electrons can be trapped and are now routinely accelerated to GeV energies. From terahertz radiation to gamma-rays, this article reviews light sources from relativistic electrons produced by LWFAs, and discusses their potential applications. Betatron motion, Compton scattering and undulators respectively produce x-rays or gamma-rays by oscillating relativistic electrons in the wakefield behind the laser pulse, a counter-propagating laser field, or a magnetic undulator. Other LWFA-based light sources include bremsstrahlung and terahertz radiation. Here, we first evaluate the performance of each of these light sources, and compare them with more conventional approaches, including radio frequency accelerators or other laser-driven sources. We have then identified applications, which we discuss in details, in a broad range of fields: medical and biological applications, military, defense and industrial applications, and condensed matter and high energy density science.

  5. R&D Status for In-Situ Plasma Surface Cleaning of SRF Cavities at Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    S.-H. Kim, M.T. Crofford, M. Doleans, J.D. Mammosser, J. Saunders

    2011-03-01

    The SNS SCL is reliably operating at 0.93 GeV output energy with an energy reserve of 10MeV with high availability. Most of the cavities exhibit field emission, which directly or indirectly (through heating of end groups) limits the gradients achievable in the high beta cavities in normal operation with the beam. One of the field emission sources would be surface contaminations during surface processing for which mild surface cleaning, if any, will help in reducing field emission. An R&D effort is in progress to develop in-situ surface processing for the cryomodules in the tunnel without disassembly. As the first attempt, in-situ plasma processing has been applied to the CM12 in the SNS SRF facility after the repair work with a promising result. This paper will report the R&D status of plasma processing in the SNS.

  6. An overview of negative hydrogen ion sources for accelerators

    Science.gov (United States)

    Faircloth, Dan; Lawrie, Scott

    2018-02-01

    An overview of high current (>1 mA) negative hydrogen ion (H-) sources that are currently used on particle accelerators. The current understanding of how H- ions are produced is summarised. Issues relating to caesium usage are explored. The different ways of expressing emittance and beam currents are clarified. Source technology naming conventions are defined and generalised descriptions of each source technology are provided. Examples of currently operating sources are outlined, with their current status and future outlook given. A comparative table is provided.

  7. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress

    Science.gov (United States)

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

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources.

  8. Conceptual design of collective ion acceleration for pulsed neutron source

    International Nuclear Information System (INIS)

    Deng Renpei; Yang Maorong

    1998-12-01

    Theoretical and experimental analysis of the collective acceleration of ions (CIA) by an electron beam to obtain pulse neutron source in an evacuated drift tube are presented. The progress and development in the world laboratories are given too. According to the requirement, the plan of neutron source produced by CIA is investigated, with Marx generator, water dielectric Blumlein line, low impedance diode and drift tube. These devices' main parameters for neutron intensity of 10 9 neutrons/pulse are given

  9. Status of the Advanced Photon Source (APS) linear accelerator

    International Nuclear Information System (INIS)

    White, M.; Berg, W.; Fuja, R.; Grelick, A.; Mavrogenes, G.; Nassiri, A.; Russell, T.; Wesolowski, W.

    1993-01-01

    A 2856-MHz S-band, 450-MeV electron/positron linear accelerator is the first part of the injector for the Advanced Photon Source (APS) 7-GeV storage ring. Construction of the APS linac is currently nearing completion, and commissioning will begin in July 1993. The linac and its current status are discussed in this paper

  10. Polarized ionic source of the tandem accelerator in Kyoto University

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Masanobu; Kuwamoto, Shuichi; Takahashi, Seiji [Kyoto Univ. (Japan). Dept. of Physics] [and others

    1997-02-01

    A polarized ion source developed under the National Laboratory of High Energy Physics was transferred to the tandem accelerator in Kyoto University at beginning of 1993 to constitute a displacement of incidence into the accelerator. This was an atomic beam type polarized ion source, which is designed to adopt permanent magnets for 6 poles magnet to polarize the electron, to take out atomic nucleus on a shape of positive ion by ECR ionizer after transferring its polarization through transition using radio frequency (RFT), to make it negative ion by charge conversion using alkaline metal vapor, and to put it into the tandem accelerator. Test of the positive ion was finished at the National Laboratory of High Energy Physics, and test in Kyoto University was required after its negative ionization. As the estimated cost was unsufficient and entrance into the ion source facility in the tandem accelerator building was limited in Kyoto University, step of development was slow. Here is reported on present state of the ion source which is now operating stably. (G.K.)

  11. Thermal shock analysis of liquid-mercury spallation target

    CERN Document Server

    Ishikura, S; Futakawa, M; Hino, R; Date, H

    2002-01-01

    The developments of the neutron scattering facilities are carried out under the high-intensity proton accelerator project promoted by JAERI and KEK. To estimate the structural integrity of the heavy liquid-metal (Hg) target used as a spallation neutron source in a MW-class neutron scattering facility, dynamic stress behavior due to the incident of a 1 MW-pulsed proton beam was analyzed by using FEM code. Two-type target containers with semi-cylindrical type and flat-plate type window were used as models for analyses. As a result, it is confirmed that the stress (pressure wave) generated by dynamic thermal shock becomes the largest at the center of window, and the flat-plate type window is more advantageous from the structural viewpoint than the semi-cylindrical type window. It has been understood that the stress generated in the window by the pressure wave can be treated as the secondary stress. (author)

  12. From reactors to long pulse sources

    International Nuclear Information System (INIS)

    Mezei, F.

    1995-01-01

    We will show, that by using an adapted instrumentation concept, the performance of a continuous source can be emulated by one switch on in long pulses for only about 10% of the total time. This 10 fold gain in neutron economy opens up the way for building reactor like sources with an order of magnitude higher flux than the present technological limits. Linac accelerator driven spallation lends itself favorably for the realization of this kind of long pulse sources, which will be complementary to short pulse spallation sources, the same way continuous reactor sources are

  13. Development of a multicusp H- ion source for accelerator applications

    International Nuclear Information System (INIS)

    York, R.L.; Stevens, R.R. Jr.

    1983-01-01

    The development of a multicusp surface-production H - ion source (Berkeley concept) designed specifically for accelerator use is described. The goal of this development effort has been to provide a suitable H - ion source for the Proton Storage Ring now being constructed at LAMPF. The ion source that has been developed is now capable of long-term operation at 20 mA of H - current at 10% duty factor and with normalized beam emittance of 0.13 cm-mrad (95% beam fraction). The development program will be described with particular emphasis on beam emittance measurements

  14. Estimation of thermochemical behavior of spallation products in mercury target

    International Nuclear Information System (INIS)

    Kobayashi, Kaoru; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Teshigawara, Makoto; Hino, Ryutaro

    2002-02-01

    In order to examine the radiation safety of a spallation mercury target system, especially source term evaluation, it is necessary to clarify the chemical forms of spallation products generated by spallation reaction with proton beam. As for the chemical forms of spallation products in mercury that involves large amounts of spallation products, these forms were estimated by using the binary phase diagrams and the thermochemical equilibrium calculation based on the amounts of spallation product. Calculation results showed that the mercury would dissolve Al, As, B, Be, Bi, C, Co, Cr, Fe, Ga, Ge, Ir, Mo, Nb, Os, Re, Ru, Sb, Si, Ta, Tc, V and W in the element state, and Ag, Au, Ba, Br, Ca, Cd, Ce, Cl, Cs, Cu, Dy, Er, Eu, F, Gd, Hf, Ho, I, In, K, La, Li, Lu, Mg, Mn, Na, Nd, Ni, O, Pb, Pd, Pr, Pt, Rb, Rh, S, Sc, Se, Sm, Sn, Sr, Tb, Te, Ti, Tl, Tm, Y, Yb, Zn and Zr in the form of inorganic mercury compounds. As for As, Be, Co, Cr, Fe, Ge, Ir, Mo, Nb, Os, Pt, Re, Ru, Se, Ta, V, W and Zr, precipitation could be occurred when increasing the amounts of spallation products with operation time of the spallation target system. On the other hand, beryllium-7 (Be-7), which is produced by spallation reaction of oxygen in the cooling water of a safety hull, becomes the main factor of the external exposure to maintain the cooling loop. Based on the thermochemical equilibrium calculation to Be-H 2 O binary system, the chemical forms of Be in the cooling water were estimated. Then the Be could exist in the form of cations such as BeOH + , BeO + and Be 2+ under the condition of less than 10 -8 of the Be mole fraction in the cooling water. (author)

  15. Estimation of thermochemical behavior of spallation products in mercury target

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Kaoru; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Teshigawara, Makoto; Hino, Ryutaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-02-01

    In order to examine the radiation safety of a spallation mercury target system, especially source term evaluation, it is necessary to clarify the chemical forms of spallation products generated by spallation reaction with proton beam. As for the chemical forms of spallation products in mercury that involves large amounts of spallation products, these forms were estimated by using the binary phase diagrams and the thermochemical equilibrium calculation based on the amounts of spallation product. Calculation results showed that the mercury would dissolve Al, As, B, Be, Bi, C, Co, Cr, Fe, Ga, Ge, Ir, Mo, Nb, Os, Re, Ru, Sb, Si, Ta, Tc, V and W in the element state, and Ag, Au, Ba, Br, Ca, Cd, Ce, Cl, Cs, Cu, Dy, Er, Eu, F, Gd, Hf, Ho, I, In, K, La, Li, Lu, Mg, Mn, Na, Nd, Ni, O, Pb, Pd, Pr, Pt, Rb, Rh, S, Sc, Se, Sm, Sn, Sr, Tb, Te, Ti, Tl, Tm, Y, Yb, Zn and Zr in the form of inorganic mercury compounds. As for As, Be, Co, Cr, Fe, Ge, Ir, Mo, Nb, Os, Pt, Re, Ru, Se, Ta, V, W and Zr, precipitation could be occurred when increasing the amounts of spallation products with operation time of the spallation target system. On the other hand, beryllium-7 (Be-7), which is produced by spallation reaction of oxygen in the cooling water of a safety hull, becomes the main factor of the external exposure to maintain the cooling loop. Based on the thermochemical equilibrium calculation to Be-H{sub 2}O binary system, the chemical forms of Be in the cooling water were estimated. Then the Be could exist in the form of cations such as BeOH{sup +}, BeO{sup +} and Be{sup 2+} under the condition of less than 10{sup -8} of the Be mole fraction in the cooling water. (author)

  16. Inverse free electron laser accelerator for advanced light sources

    Directory of Open Access Journals (Sweden)

    J. P. Duris

    2012-06-01

    Full Text Available We discuss the inverse free electron laser (IFEL scheme as a compact high gradient accelerator solution for driving advanced light sources such as a soft x-ray free electron laser amplifier or an inverse Compton scattering based gamma-ray source. In particular, we present a series of new developments aimed at improving the design of future IFEL accelerators. These include a new procedure to optimize the choice of the undulator tapering, a new concept for prebunching which greatly improves the fraction of trapped particles and the final energy spread, and a self-consistent study of beam loading effects which leads to an energy-efficient high laser-to-beam power conversion.

  17. Research opportunities with compact accelerator-driven neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, I.S. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Andreani, C., E-mail: carla.andreani@uniroma2.it [Università degli Studi di Roma “Tor Vergata”, Physics Department and NAST Centre, Via della Ricerca Scientifica 1, 00133 Roma (Italy); CNR-IPCF Sezione di Messina, Messina (Italy); Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma (Italy); Carpenter, J.M. [Argonne National Laboratory, Argonne, IL (United States); Festa, G., E-mail: giulia.festa@uniroma2.it [Università degli Studi di Roma “Tor Vergata”, Physics Department and NAST Centre, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma (Italy); Gorini, G. [Università degli Studi di Milano—Bicocca, Milano (Italy); Loong, C.-K. [Università degli Studi di Roma “Tor Vergata”, Centro NAST, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Senesi, R. [Università degli Studi di Roma “Tor Vergata”, Physics Department and NAST Centre, Via della Ricerca Scientifica 1, 00133 Roma (Italy); CNR-IPCF Sezione di Messina, Messina (Italy); Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma (Italy)

    2016-10-13

    Since the discovery of the neutron in 1932 neutron beams have been used in a very broad range of applications, As an aging fleet of nuclear reactor sources is retired the use of compact accelerator-driven neutron sources (CANS) is becoming more prevalent. CANS are playing a significant and expanding role in research and development in science and engineering, as well as in education and training. In the realm of multidisciplinary applications, CANS offer opportunities over a wide range of technical utilization, from interrogation of civil structures to medical therapy to cultural heritage study. This paper aims to provide the first comprehensive overview of the history, current status of operation, and ongoing development of CANS worldwide. The basic physics and engineering regarding neutron production by accelerators, target–moderator systems, and beam line instrumentation are introduced, followed by an extensive discussion of various evolving applications currently exploited at CANS.

  18. A review of ion sources for medical accelerators (invited).

    Science.gov (United States)

    Muramatsu, M; Kitagawa, A

    2012-02-01

    There are two major medical applications of ion accelerators. One is a production of short-lived isotopes for radionuclide imaging with positron emission tomography and single photon emission computer tomography. Generally, a combination of a source for negative ions (usually H- and/or D-) and a cyclotron is used; this system is well established and distributed over the world. Other important medical application is charged-particle radiotherapy, where the accelerated ion beam itself is being used for patient treatment. Two distinctly different methods are being applied: either with protons or with heavy-ions (mostly carbon ions). Proton radiotherapy for deep-seated tumors has become widespread since the 1990s. The energy and intensity are typically over 200 MeV and several 10(10) pps, respectively. Cyclotrons as well as synchrotrons are utilized. The ion source for the cyclotron is generally similar to the type for production of radioisotopes. For a synchrotron, one applies a positive ion source in combination with an injector linac. Carbon ion radiotherapy awakens a worldwide interest. About 6000 cancer patients have already been treated with carbon beams from the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan. These clinical results have clearly verified the advantages of carbon ions. Heidelberg Ion Therapy Center and Gunma University Heavy Ion Medical Center have been successfully launched. Several new facilities are under commissioning or construction. The beam energy is adjusted to the depth of tumors. It is usually between 140 and 430 MeV∕u. Although the beam intensity depends on the irradiation method, it is typically several 10(8) or 10(9) pps. Synchrotrons are only utilized for carbon ion radiotherapy. An ECR ion source supplies multi-charged carbon ions for this requirement. Some other medical applications with ion beams attract developer's interests. For example, the several types of accelerators are

  19. Method for controlling an accelerator-type neutron source, and a pulsed neutron source

    International Nuclear Information System (INIS)

    Givens, W.W.

    1991-01-01

    The patent deals with an accelerator-type neutron source which employs a target, an ionization section and a replenisher for supplying accelerator gas. A positive voltage pulse is applied to the ionization section to produce a burst of neutrons. A negative voltage pulse is applied to the ionization section upon the termination of the positive voltage pulse to effect a sharp cut-off to the burst of neutrons. 4 figs

  20. Accelerator-based cold neutron sources and their cooling system

    International Nuclear Information System (INIS)

    Inoue, Kazuhiko; Yanai, Masayoshi; Ishikawa, Yoshikazu.

    1985-01-01

    We have developed and installed two accelerator-based cold neutron sources within a electron linac at Hokkaido University and a proton synchrotoron at National Laboratory for High Energy Physics. Solid methane at 20K was adopted as the cold moderator. The methane condensing heat exchangers attached directly to the moderator chambers were cooled by helium gas, which was kept cooled in refrigerators and circulated by ventilation fans. Two cold neutron sources have operated smoothly and safely for the past several years. In this paper we describe some of the results obtained in the preliminary experiments by using a modest capacity refrigerator, the design philosophy of the cooling system for the pulsed cold neutron sources, and outline of two facilities. (author)

  1. 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

  2. Accelerator shield design of KIPT neutron source facility

    International Nuclear Information System (INIS)

    Zhong, Z.; Gohar, Y.

    2013-01-01

    Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of a neutron source facility at KIPT utilizing an electron-accelerator-driven subcritical assembly. Electron beam power is 100 kW, using 100 MeV electrons. The facility is designed to perform basic and applied nuclear research, produce medical isotopes, and train young nuclear specialists. The biological shield of the accelerator building is designed to reduce the biological dose to less than 0.5-mrem/hr during operation. The main source of the biological dose is the photons and the neutrons generated by interactions of leaked electrons from the electron gun and accelerator sections with the surrounding concrete and accelerator materials. The Monte Carlo code MCNPX serves as the calculation tool for the shield design, due to its capability to transport electrons, photons, and neutrons coupled problems. The direct photon dose can be tallied by MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is less than 0.01 neutron per electron. This causes difficulties for Monte Carlo analyses and consumes tremendous computation time for tallying with acceptable statistics the neutron dose outside the shield boundary. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were developed for the study. The generated neutrons are banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron and secondary photon doses. The weight windows variance reduction technique is utilized for both neutron and photon dose calculations. Two shielding materials, i.e., heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total

  3. New modes of particle accelerations techniques and sources. Formal report

    Energy Technology Data Exchange (ETDEWEB)

    Parsa, Z. [ed.

    1996-12-31

    This Report includes copies of transparencies and notes from the presentations made at the Symposium on New Modes of Particle Accelerations - Techniques and Sources, August 19-23, 1996 at the Institute for Theoretical Physics, University of California, Santa Barbara California, that was made available by the authors. Editing, reduction and changes to the authors contributions were made only to fulfill the printing and publication requirements. We would like to take this opportunity and thank the speakers for their informative presentations and for providing copies of their transparencies and notes for inclusion in this Report.

  4. New modes of particle accelerations techniques and sources. Formal report

    International Nuclear Information System (INIS)

    Parsa, Z.

    1996-01-01

    This Report includes copies of transparencies and notes from the presentations made at the Symposium on New Modes of Particle Accelerations - Techniques and Sources, August 19-23, 1996 at the Institute for Theoretical Physics, University of California, Santa Barbara California, that was made available by the authors. Editing, reduction and changes to the authors contributions were made only to fulfill the printing and publication requirements. We would like to take this opportunity and thank the speakers for their informative presentations and for providing copies of their transparencies and notes for inclusion in this Report

  5. A high current, short pulse electron source for wakefield accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed.

  6. A high current, short pulse electron source for wakefield accelerators

    International Nuclear Information System (INIS)

    Ho, Ching-Hung.

    1992-01-01

    Design studies for the generation of a high current, short pulse electron source for the Argonne Wakefield Accelerator are presented. An L-band laser photocathode rf gun cavity is designed using the computer code URMEL to maximize the electric field on the cathode surface for fixed frequency and rf input power. A new technique using a curved incoming laser wavefront to minimize the space charge effect near the photocathode is studied. A preaccelerator with large iris to minimize wakefield effects is used to boost the drive beam to a useful energy of around 20 MeV for wakefield acceleration experiments. Focusing in the photocathode gun and the preaccelerator is accomplished with solenoids. Beam dynamics simulations throughout the preaccelerator are performed using particle simulation codes TBCI-SF and PARMELA. An example providing a useful set of operation parameters for the Argonne Wakefield Accelerator is given. The effects of the sagitta of the curved beam and laser amplitude and timing jitter effects are discussed. Measurement results of low rf power level bench tests and a high power test for the gun cavity are presented and discussed

  7. Development of Advanced Fourth Generation Light Sources for the Accelerator Science Laboratory

    OpenAIRE

    Chanwattana, Thakonwat; Bartolini, Riccardo; Seryi, Andrei; Tsesmelis, Emmanuel

    2015-01-01

    The John Adams Institute for Accelerator Science (JAI) has proposed the realisation of the Accelerator Science Laboratory (ASL) at the University of Oxford as a facility for the development of advanced compact light sources enabling accelerator science research and applications. The installation of a compact light source in the ASL is planned with two options for the accelerating technologies. Firstly, a conventional RF based accelerator is considered to be a driver for a short pulse THz cohe...

  8. 8 May 2013 - Swedish European Spallation Source Chief Executive Officer J. H. Yeck in the ATLAS visitor centre and experimental cavern with Collaboration Spokesperson D. Charlton (also present M. Nessi, R. Garoby and E. Tsesmelis); signing the guest book with International Relations Adviser E. Tsesmelis.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    8 May 2013 - Swedish European Spallation Source Chief Executive Officer J. H. Yeck in the ATLAS visitor centre and experimental cavern with Collaboration Spokesperson D. Charlton (also present M. Nessi, R. Garoby and E. Tsesmelis); signing the guest book with International Relations Adviser E. Tsesmelis.

  9. Ion source memory in {sup 36}Cl accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pavetich, Stefan; Akhmadaliev, Shavkat; Merchel, Silke; Rugel, Georg [HZDR, Dresden (Germany); Arnold, Maurice; Aumaitre, Georges; Bourles, Didier; Martschini, Martin [ASTER, Aix-en-Provence (France); Buchriegler, Josef; Golser, Robin; Keddadouche, Karim; Steier, Peter [VERA, Vienna (Austria)

    2013-07-01

    Since the DREAMS (Dresden Accelerator Mass Spectrometry) facility went operational in 2011, constant effort was put into enabling routine measurements of long-lived radionuclides as {sup 10}Be, {sup 26}Al and {sup 41}Ca. For precise AMS-measurements of the volatile element Cl the key issue is the minimization of the long term memory effect. For this purpose one of the two original HVE sources was mechanically modified, allowing the usage of bigger cathodes with individual target apertures. Additionally a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, a small inter-laboratory comparison had been initiated. The long-term memory effect in the Cs sputter ion sources of the AMS facilities VERA, ASTER and DREAMS had been investigated by running samples of natural {sup 35}Cl/{sup 37}Cl-ratio and samples containing highly enriched {sup 35}Cl({sup 35}Cl/{sup 37}Cl > 500). Primary goals of the research are the time constants of the recovery from the contaminated sample ratio to the initial ratio of the sample and the level of the long-term memory effect in the sources.

  10. Mercury erosion experiments for spallation target system

    International Nuclear Information System (INIS)

    Kinoshita, Hidetaka; Kaminaga, Masanori; Haga, Katsuhiro; Hino, Ryutaro

    2003-01-01

    The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a plan to construct the spallation neutron source at the Tokai Research Establishment, JAERI, under the High-Intensity Proton Accelerator Project (J-PARC). A mercury circulation system has been designed so as to supply mercury to the target stably under the rated flow rate of 41 m 3 /hr. Then, it was necessary to confirm a mercury pump performance from the viewpoint of making the mercury circulation system feasible, and more, to investigate erosion rate under the mercury flow as well as an amount of mercury remained on the surface after drain from the viewpoints of mechanical strength relating to the lifetime and remote handling of mercury components. The mercury pump performance was tested under the mercury flow conditions by using an experimental gear pump, which had almost the same structure as a practical mercury pump to be expected in the mercury circulation system, and the erosion rates in a mercury pipeline as well as the amount of mercury remained on the surface were also investigated. The discharged flow rates of the experimental gear pump increased linearly with the rotation speed, so that the gear pump would work as the flow meter. Erosion rates obtained under the mercury velocity less than 1.6 m/s was found to be so small that decrease of pipeline wall thickness would be 390 μm after 30-year operation under the rated mercury velocity of 0.7 m/s. For the amount of remaining mercury on the pipeline, remaining rates of weight and volume were estimated at 50.7 g/m 2 and 3.74 Hg-cm 3 /m 2 , respectively. Applying these remaining rates of weight and volume to the mercury target, the remaining mercury was estimated at about 106.5 g and 7.9 cm 3 . Radioactivity of this remaining mercury volume was found to be three-order lower than that of the target casing. (author)

  11. Fundamentals and applications of neutron imaging. Fundamentals part 5. Neutron sources for neutron imaging

    International Nuclear Information System (INIS)

    Matsubayashi, Masahito

    2007-01-01

    Neutrons for experiments by neutron beams are classified regarding neutron sources as follows: (1) Neutrons from radioisotopes, (2) Neutrons from nuclear reactions induced by deuteron beams from accelerators, (3) Neutrons from nuclear spallation induced by high energy proton beams from accelerators, and (4) Neutrons from reactors. As for the neutron imaging, weak intensity neutron sources can be useful if the detector system is sensitive enough. A newly developed spallation neutron source has eminent characteristics that the neutron emission is pulsive with strong peak intensity. Imaging experiments availing this property will be developed henceforth. (K. Yoshida)

  12. Laser-accelerated proton beams as a new particle source

    International Nuclear Information System (INIS)

    Nuernberg, Frank

    2010-01-01

    Darmstadt initiated the development of a test stand to transport, focus and bunch rotate these beams by conventional ion optics and RF technology. The field strength of 7.5 T enabled collimation of protons with an energy of >10 MeV for the first time. In addition, the focusing capability of the solenoid provided a flux increase in the focal spot of about a factor of 174 at a distance of 40 cm from the source, compared to a beam without using the magnetic field. For a quantitative analysis of the experiment numerical simulations with the WarpRZ code were performed. The code, which was originally developed to study high current ion beams and aid in the pursuit of heavy-ion driven inertial confinement fusion, was modified to enable the use of laser-accelerated proton beams as particle source. The calculated energy-resolved beam parameters of RIS could be included, and the plasma simulation criteria were studied in detail. The geometrical boundaries of the experimental setup were used in the simulations. 2.99 x 10 9 collimated protons in the energy range of 13.5±1 MeV could be transported over a distance of 40 cm. In addition, 8.42 x 10 9 protons in the energy range of 6.7±0.2 MeV were focused into a spot of <2 mm in diameter. The transmission through the solenoid for both cases was about 18%. (orig.)

  13. Laser-accelerated proton beams as a new particle source

    Energy Technology Data Exchange (ETDEWEB)

    Nuernberg, Frank

    2010-11-15

    plasma physics group of the Technische Universitat Darmstadt initiated the development of a test stand to transport, focus and bunch rotate these beams by conventional ion optics and RF technology. The field strength of 7.5 T enabled collimation of protons with an energy of >10 MeV for the first time. In addition, the focusing capability of the solenoid provided a flux increase in the focal spot of about a factor of 174 at a distance of 40 cm from the source, compared to a beam without using the magnetic field. For a quantitative analysis of the experiment numerical simulations with the WarpRZ code were performed. The code, which was originally developed to study high current ion beams and aid in the pursuit of heavy-ion driven inertial confinement fusion, was modified to enable the use of laser-accelerated proton beams as particle source. The calculated energy-resolved beam parameters of RIS could be included, and the plasma simulation criteria were studied in detail. The geometrical boundaries of the experimental setup were used in the simulations. 2.99 x 10{sup 9} collimated protons in the energy range of 13.5{+-}1 MeV could be transported over a distance of 40 cm. In addition, 8.42 x 10{sup 9} protons in the energy range of 6.7{+-}0.2 MeV were focused into a spot of <2 mm in diameter. The transmission through the solenoid for both cases was about 18%. (orig.)

  14. 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.

  15. Spallation products from a lead target bombarded by 120-MeV deuterons: Calculations and measurements

    International Nuclear Information System (INIS)

    Parish, T.A.; Cochran, R.G.; Beard, C.A.

    1993-01-01

    Spallation neutron sources have recently received increased interest for nuclear waste transmutation and tritium production applications. One important advantage of spallation sources is their prodigious neutron production without the concomitant generation of actinide and fission product wastes. While there has been considerable research to verify the number of neutrons produced per incident beam particle on various targets, there has been less effort to quantify the amounts and types of nuclei produced. Accurate knowledge of the radioactive species produced as a result of spallation reactions will be important for specifying disposal options for spallation targets. To supplement the available data, an experimental study has been conducted at Texas A ampersand M University (TAMU) to compare measured and calculated spallation product yields from a lead target

  16. A spallation-based irradiation test facility for fusion and future fission materials

    CERN Document Server

    Samec, K; Kadi, Y; Luis, R; Romanets, Y; Behzad, M; Aleksan, R; Bousson, S

    2014-01-01

    The EU’s FP7 TIARA program for developing accelerator-based facilities has recently demonstrated the unique capabilities of a compact and powerful spallation source for irradiating advanced nuclear materials. The spectrum and intensity of the neutron flux produced in the proposed facility fulfils the requirements of the DEMO fusion reactor for ITER, ADS reactors and also Gen III / IV reactors. Test conditions can be modulated, covering temperature from 400 to 550°C, liquid metal corrosion, cyclical or static stress up to 500 MPa and neutron/proton irradiation damage of up to 25 DPA per annum. The entire “TMIF” facility fits inside a cube 2 metres on a side, and is dimensioned for an accelerator beam power of 100 kW, thus reducing costs and offering great versatility and flexibility.

  17. Microwave Ion Source and Beam Injection for an Accelerator-driven Neutron Source

    International Nuclear Information System (INIS)

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

    2007-01-01

    An over-dense microwave driven ion source capable of producing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomic fraction >90 percent was designed and tested with an electrostatic low energy beam transport section (LEBT). This ion source was incorporated into the design of an Accelerator Driven Neutron Source (ADNS). The other key components in the ADNS include a 6 MeV RFQ accelerator, a beam bending and scanning system, and a deuterium gas target. In this design a 40 mA D+ beam is produced from a 6 mm diameter aperture using a 60 kV extraction voltage. The LEBT section consists of 5 electrodes arranged to form 2 Einzel lenses that focus the beam into the RFQ entrance. To create the ECR condition, 2 induction coils are used to create ∼ 875 Gauss on axis inside the source chamber. To prevent HV breakdown in the LEBT a magnetic field clamp is necessary to minimize the field in this region. Matching of the microwave power from the waveguide to the plasma is done by an autotuner. We observed significant improvement of the beam quality after installing a boron nitride liner inside the ion source. The measured emittance data are compared with PBGUNS simulations

  18. Microwave Ion Source and Beam Injection for an Accelerator-Driven Neutron Source

    International Nuclear Information System (INIS)

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

    2007-01-01

    An over-dense microwave driven ion source capable of producing deuterium (or hydrogen) beams at 100-200 mA/cm 2 and with atomic fraction > 90% was designed and tested with an electrostatic low energy beam transport section (LEBT). This ion source was incorporated into the design of an Accelerator Driven Neutron Source (ADNS). The other key components in the ADNS include a 6 MeV RFQ accelerator, a beam bending and scanning system, and a deuterium gas target. In this design a 40 mA D + beam is produced from a 6 mm diameter aperture using a 60 kV extraction voltage. The LEBT section consists of 5 electrodes arranged to form 2 Einzel lenses that focus the beam into the RFQ entrance. To create the ECR condition, 2 induction coils are used to create ∼ 875 Gauss on axis inside the source chamber. To prevent HV breakdown in the LEBT a magnetic field clamp is necessary to minimize the field in this region. Matching of the microwave power from the waveguide to the plasma is done by an autotuner. They observed significant improvement of the beam quality after installing a boron nitride liner inside the ion source. The measured emittance data are compared with PBGUNS simulations

  19. Nuclear energy generation and waste transmutation using an accelerator-driven intense thermal neutron source

    International Nuclear Information System (INIS)

    Bowman, C.D.; Arthur, E.D.; Lisowski, P.W.; Lawrence, G.P.; Jensen, R.J.; Anderson, J.L.; Blind, B.; Cappiello, M.; Davidson, J.W.; England, T.R.; Engel, L.N.; Haight, R.C.; Hughes, H.G. III; Ireland, J.R.; Krakowski, R.A.; LaBauve, R.J.; Letellier, B.C.; Perry, R.T.; Russell, G.J.; Staudhammer, K.P.; Versamis, G.; Wilson, W.B.

    1992-01-01

    We describe a new approach for commercial nuclear energy production without a long-term high-level waste stream and for transmutation of both fission product and higher actinide commercial nuclear waste using a thermal flux of accelerator-produced neutrons in the 10 16 n/cm 2 s range. Continuous neutron fluxes at this intensity, which is approximately 100 times larger than is typically available in a large scale thermal reactor, appear practical, owing to recent advances in proton linear accelerator technology and to the spallation target-moderator design presented here. This large flux of thermal neutrons makes possible a waste inventory in the transmutation system which is smaller by about a factor of 100 than competing concepts. The accelerator allows the system to operate well below criticality so that the possibility for a criticality accident is eliminated. No control rods are required. The successful implementation of this new method for energy generation and waste transmutation would eliminate the need for nuclear waste storage on a geologic time scale. The production of nuclear energy from 232 Th or 238 U is used to illustrate the general principles of commercial nuclear energy, production without long-term high-level waste. There appears to be sufficient thorium to meet the world's energy needs for many millenia. (orig.)

  20. System and safety studies of accelerator driven transmutation systems. Annual report 1999

    Energy Technology Data Exchange (ETDEWEB)

    Gudowski, Waclaw; Wallenius, Jan; Eriksson, Marcus; Carlsson, Johan; Seltborg, Per; Tucek, Kamil [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Nuclear and Reactor Physics

    2000-05-01

    In 1996, SKB commenced funding of the project 'System and safety studies of accelerator driven transmutation systems and development of a spallation target'. The aim of the project was stated as: Development of a complete code for simulation of transmutation processes in an accelerator driven system. Application of the code for analysis of neutron flux, transmutation rates, reactivity changes, toxicity and radiation damages in the transmutation core. Build up of competence regarding issues related to spallation targets, development of research activities regarding relevant material issues. Performing of basic experiments in order to investigate the adequacy of using the spallation. target as a neutron source for a transmutation system, and participation in the planning and implementation of an international demonstration experiment. In the present report, activities within and related to the framework of the project, performed at the department of Nuclear and Reactor Physics at the Royal Institute of Technology during 1999, are accounted for.

  1. System and safety studies of accelerator driven transmutation systems. Annual report 1997

    International Nuclear Information System (INIS)

    Wallenius, J.; Carlsson, Johan; Gudowski, W.

    1997-12-01

    In November 1996, SKB started financing of the project ''System and safety studies of accelerator driven transmutation systems and development of a spallation target''. The aim of the project was stated as: 1) Development of a complete code for simulation of transmutation processes in an accelerator driven system. Application of the code for analysis of neutron flux, transmutation rates, reactivity changes, toxicity and radiation damages in the transmutation core. 2) Build up of competence regarding issues related to spallation targets development of research activities regarding relevant material issues. Performing of basic experiments in order to investigate the adequacy of using the spallation target as a neutron source for a transmutation system, and participation in the planning and implementation of an international demonstration-experiment. In the present report, activities within the framework of the project performed at the department of Nuclear and Reactor Physics at the Royal Institute of Technology during 1997, are accounted for

  2. GRAIN-SCALE FAILURE IN THERMAL SPALLATION DRILLING

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, S C; Lomov, I; Roberts, J J

    2012-01-19

    Geothermal power promises clean, renewable, reliable and potentially widely-available energy, but is limited by high initial capital costs. New drilling technologies are required to make geothermal power financially competitive with other energy sources. One potential solution is offered by Thermal Spallation Drilling (TSD) - a novel drilling technique in which small particles (spalls) are released from the rock surface by rapid heating. While TSD has the potential to improve drilling rates of brittle granitic rocks, the coupled thermomechanical processes involved in TSD are poorly described, making system control and optimization difficult for this drilling technology. In this paper, we discuss results from a new modeling effort investigating thermal spallation drilling. In particular, we describe an explicit model that simulates the grain-scale mechanics of thermal spallation and use this model to examine existing theories concerning spalling mechanisms. We will report how borehole conditions influence spall production, and discuss implications for macro-scale models of drilling systems.

  3. Spallation-mechanism and characteristics

    International Nuclear Information System (INIS)

    Strugalski, Z.; Strugalska-Gola, E.; Wojciechowski, A.

    1996-01-01

    Mechanism of spallation is revealed experimentally. Spallation is a complicated nuclear reaction initiated by fast hadron in which three stages may be distinguished: a) the first stage in which the target nucleus is locally damaged, it lasts ∼10 -24 +10 -22 s; b) the slow stage which lasts ∼10 -22 +10 -17 s after the collision started, the damaged and excited nucleus uses to emit the black track leaving particles; c) the final stage in which residual target nucleus uses to split into two or more fragments. Quantitative characteristics of each of the stages are presented. 35 refs

  4. Towards the construction of the European spallation source–The ...

    Indian Academy of Sciences (India)

    The possible realization of the European spallation source has been a long and winding story. However, thanks to the conjunction of a number of events it now looks highly probable that in 2008 there will indeed be a decision on the site and on a funding partnership of European countries who will together build and ...

  5. A monolithic relativistic electron beam source based on a dielectric laser accelerator structure

    Energy Technology Data Exchange (ETDEWEB)

    McNeur, Josh; Carranza, Nestor; Travish, Gil; Yin Hairong; Yoder, Rodney [UCLA Dept. of Physics and Astronomy, Los Angeles, CA 90095 (United States); College of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); Manhattanville College, Physics Dept., 2900 Purchase St., Purchase, NY 10577 (United States)

    2012-12-21

    Work towards a monolithic device capable of producing relativistic particle beams within a cubic-centimeter is detailed. We will discuss the Micro-Accelerator Platform (MAP), an optical laser powered dielectric accelerator as the main building block of this chip-scale source along with a field enhanced emitter and a region for sub-relativistic acceleration.

  6. 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.

  7. 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.)

  8. 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)

  9. CFD analysis of the HYPER spallation target

    International Nuclear Information System (INIS)

    Cho, Chungho; Tak, Nam-il; Choi, Jae-Hyuk; Lee, Yong-Bum

    2008-01-01

    KAERI (Korea Atomic Energy Research Institute) is developing an accelerator driven system (ADS) named HYPER (HYbrid Power Extraction Reactor) for a transmutation of long-lived nuclear wastes. One of the challenging tasks for the HYPER system is to design a large spallation target with a beam power of 15-25 MW. The paper focuses on a thermal-hydraulic analysis of the active part of the HYPER target. Computational fluid dynamics (CFD) analysis was performed by using a commercial code CFX 5.7.1. Several advanced turbulence models with different grid structures were applied. The CFX results reveal a significant impact of the turbulence model on the window temperature. Particularly, the k-ε model predicts the lowest window temperature among the five investigated turbulence models

  10. RAMI analysis and modeling for the LANSCE accelerator systems

    Energy Technology Data Exchange (ETDEWEB)

    Macek, R.J.; Wilkinson, C.A. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    Reliability, availability, maintainability, and inspectability (RAMI) have become important issues for the high-power machines being planned for applications such as accelerator transmutation of nuclear waste (ATW), accelerator production of tritium (APT) and the next generation spallation neutron source. Beam reliability and beam availability are vitally important specifications to the present users of accelerator-driven spallation neutron sources, synchrotron light sources and medical accelerators. At Los Alamos, improved beam availability is a key goal in the planned LANSCE improvement program. Clearly, the capability to adequately model and predict the reliability and availability of complex accelerator systems will be of great value in assessing and optimizing RAMI measures in accelerator design and improvement programs. To date, no major accelerator project has developed comprehensive reliability models although the Advance Photon Source at ANL has started work on reliability analysis for selected subsystems. In this paper the authors discuss their experience in developing RAMI analysis and modeling for the LANSCE Accelerator Systems. Progress has been made in developing suitable measures and functions to characterize user risk, in logging of needed data on failure rates and repair/down times, and in developing a first-pass RAMI model for selected subsystems. Plans have been made for a more complete RAMI model. In addition, the authors discuss their experience in the use of probabilistic risk assessment (PRA) methodology for estimation of the reliability of active, instrumentation-based, radiation safety systems at LANSCE.

  11. RAMI analysis and modeling for the LANSCE accelerator systems

    International Nuclear Information System (INIS)

    Macek, R.J.; Wilkinson, C.A.

    1995-01-01

    Reliability, availability, maintainability, and inspectability (RAMI) have become important issues for the high-power machines being planned for applications such as accelerator transmutation of nuclear waste (ATW), accelerator production of tritium (APT) and the next generation spallation neutron source. Beam reliability and beam availability are vitally important specifications to the present users of accelerator-driven spallation neutron sources, synchrotron light sources and medical accelerators. At Los Alamos, improved beam availability is a key goal in the planned LANSCE improvement program. Clearly, the capability to adequately model and predict the reliability and availability of complex accelerator systems will be of great value in assessing and optimizing RAMI measures in accelerator design and improvement programs. To date, no major accelerator project has developed comprehensive reliability models although the Advance Photon Source at ANL has started work on reliability analysis for selected subsystems. In this paper the authors discuss their experience in developing RAMI analysis and modeling for the LANSCE Accelerator Systems. Progress has been made in developing suitable measures and functions to characterize user risk, in logging of needed data on failure rates and repair/down times, and in developing a first-pass RAMI model for selected subsystems. Plans have been made for a more complete RAMI model. In addition, the authors discuss their experience in the use of probabilistic risk assessment (PRA) methodology for estimation of the reliability of active, instrumentation-based, radiation safety systems at LANSCE

  12. ACCELERATING THE ADOPTION PROCESS OF RENEWABLE ENERGY SOURCES AMONG SMES

    Directory of Open Access Journals (Sweden)

    Mirjam Leloux

    2015-07-01

    Full Text Available By 2020, intermittent renewable small scale energy sources (e.g. wind and solar energy are expected to represent about 17% of the EU’s total electricity consumption. All national overriding energy policy objectives are to ensure competitive, secure and sustainable energy for the economy and for society. Renewable energy, allied with energy efficiency, is often found crucial to meet these goals of secure sustainable and competitive energy supplies reducing dependency on expensive fossil imports and underpinning the move towards a low carbon economy while delivering green jobs to the economy. This all contributes to national competitiveness and the jobs and economic growth agenda. However, a straight forward implementation of renewable energy options is not easy, due to various barriers and obstacles. For most SMEs, the concept of generating their own renewable energy is still more of academic than genuine interest. In general, several barriers are experienced, such as high capital investments, slow return on investment, and the lack of knowledge of the benefits. There is a need for education on the benefits and drawbacks of sustainable energy, as well as a greater contribution to costs for this to work. In this paper we describe the intermediate outcomes of a European Partnership under the name of GREAT (Growing Renewable Energy Applications and Technologies, funded under the INTERREG IVB NWE Programme. GREAT aims to encourage communities and small to medium size enterprises (SMEs in Ireland, the United Kingdon, Belgium and The Netherlands to develop technological solutions for Smart Grid, Renewable Energy and Distributive Generation; research and develop policy issues for regulatory authorities and provide structured co-operation opportunities between SMEs and research institutes / technology developers. We developed GREAT spreadsheets to facilitate SMEs in each country to calculate the return-on-investment of renewable energy sources, such as

  13. Laser-driven wakefield electron acceleration and associated radiation sources

    International Nuclear Information System (INIS)

    Davoine, X.

    2009-10-01

    The first part of this research thesis introduces the basic concepts needed for the understanding of the laser-driven wakefield acceleration. It describes the properties of the used laser beams and plasmas, presents some notions about laser-plasma interactions for a better understanding of the physics of laser-driven acceleration. The second part deals with the numerical modelling and the presentation of simulation tools needed for the investigation of laser-induced wakefield acceleration. The last part deals with the optical control of the injection, a technique analogous to the impulsion collision scheme

  14. Accelerators for condensed matter research

    International Nuclear Information System (INIS)

    Williams, P.R.

    1990-01-01

    The requirement for high energy, high luminosity beams has stimulated the science and engineering of accelerators to a point where they open up opportunities for new areas of scientific application to benefit from the advances driven by particle physics. One area of great importance is the use of electron or positron storage rings as a source of intense VUV or X-ray synchrotron radiation. An accelerator application that has grown in prominence over the last 10 years has been spallation neutron sources. Neutrons offer an advantage over X-rays as a condensed matter probe because the neutron energy is usually of the same order as the room temperature thermal energy fluctuations in the sample being studied. Another area in which accelerators are playing an increasingly important role in condensed matter research concerns the use of Mu mesons, Muons, as a probe. This paper also presents a description of the ISIS Spallation Neutron Source. The design and status of the facility are described, and examples are given of its application to the study of condensed matter. (N.K.)

  15. 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 ...

  16. 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...

  17. Safety analysis and lay-out aspects of shieldings against particle radiation at the example of spallation facilities in the megawatt range; Sicherheitstechnische Analyse und Auslegungsaspekte von Abschirmungen gegen Teilchenstrahlung am Beispiel von Spallationsanlagen im Megawatt Bereich

    Energy Technology Data Exchange (ETDEWEB)

    Hanslik, R.

    2006-08-15

    This paper discusses the shielding of particle radiation from high current accelerators, spallation neutron sources and so called ADS-facilities (Accelerator Driven Systems). ADS-facilities are expected to gain importance in the future for transmutation of long-lived isotopes from fission reactors as well as for energy production. In this paper physical properties of the radiation as well as safety relevant requirements and corresponding shielding concepts are discussed. New concepts for the layout and design of such shielding are presented. Focal point of this work will be the fundamental difference between conventional fission reactor shielding and the safety relevant issues of shielding from high-energy radiation. Key point of this paper is the safety assessment of shielding issues of high current accelerators, spallation targets and ADS-blanket systems as well as neutron scattering instruments at spallation neutron sources. Safety relevant shielding requirements are presented and discussed. For the layout and design of the shielding for spallation sources computer base calculations methods are used. A discussion and comparison of the most important methods like semi-empirical, deterministic and stochastic codes are presented. Another key point within the presented paper is the discussion of shielding materials and their shielding efficiency concerning different types of radiation. The use of recycling material, as a cost efficient solution, is discussed. Based on the conducted analysis, flowcharts for a systematic layout and design of adequate shielding for targets and accelerators have been developed and are discussed in this paper. By use of these flowcharts layout and engineering design of future ADS-facilities can be performed. (orig.)

  18. How should the JAERI neutron source be designed?

    International Nuclear Information System (INIS)

    Watanabe, Noboru

    1996-01-01

    The importance of a next-generation neutron source in JAERI is discussed. The feasibility and the performances of three types of neutron sources, namely continuous wave spallation source (CWSS), long-pulse spallation source (LPSS) and short-pulse spallation source (SPSS), are compared based on a proposed JAERI accelerator, a superconducting (SC) proton linac (1-1.5 GeV, 25-16 mA in peak current, finally CW). How to realize one of the world's best neutron source using such a linac with a modest beam-current and what type of neutron source is the best for such a linac are the most important current problems. Since the accelerator is not favorable for LPSS due to a lower peak current and there exist serious technical problems for a CWSS target, a short-pulse spallation source would be the best candidate to realize a 5 MW-class SPSS like ESS, provided that the H - -injection to a compressor ring over a long pulse duration (>2 ms) is feasible. (author)

  19. 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)

  20. 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)

  1. Multicavity proton cyclotron accelerator

    Directory of Open Access Journals (Sweden)

    J. L. Hirshfield

    2002-08-01

    Full Text Available A mechanism for acceleration of protons is described, in which energy gain occurs near cyclotron resonance as protons drift through a sequence of rotating-mode TE_{111} cylindrical cavities in a strong nearly uniform axial magnetic field. Cavity resonance frequencies decrease in sequence from one another with a fixed frequency interval Δf between cavities, so that synchronism can be maintained between the rf fields and proton bunches injected at intervals of 1/Δf. An example is presented in which a 122 mA, 1 MeV proton beam is accelerated to 961 MeV using a cascade of eight cavities in an 8.1 T magnetic field, with the first cavity resonant at 120 MHz and with Δf=8 MHz. Average acceleration gradient exceeds 40 MV/m, average effective shunt impedance is 223 MΩ/m, but maximum surface field in the cavities does not exceed 7.2 MV/m. These features occur because protons make many orbital turns in each cavity and thus experience acceleration from each cavity field many times. Longitudinal and transverse stability appear to be intrinsic properties of the acceleration mechanism, and an example to illustrate this is presented. This acceleration concept could be developed into a proton accelerator for a high-power neutron spallation source, such as that required for transmutation of nuclear waste or driving a subcritical fission burner, provided a number of significant practical issues can be addressed.

  2. Plasma Acceleration by Rotating Magnetic Field Method using Helicon Source

    Science.gov (United States)

    Furukawa, Takeru; Shimura, Kaichi; Kuwahara, Daisuke; Shinohara, Shunjiro

    2017-10-01

    Electrodeless plasma thrusters are very promising due to no electrode damage, leading to realize further deep space exploration. As one of the important proposals, we have been concentrating on Rotating Magnetic Field (RMF) acceleration method. High-dense plasma (up to 1013 cm-3) can be generated by using a radio frequency (rf) external antenna, and also accelerated by an antenna wound around outside of a discharge tube. In this scheme, thrust increment is achieved by the axial Lorentz force caused by non linear effects. RMF penetration condition into plasma can be more satisfied than our previous experiment, by increasing RMF coil current and decreasing the RMF frequency, causing higher thrust and fuel efficiency. Measurements of AC RMF component s have been conducted to investigate the acceleration mechanism and the field penetration experimentally. This study has been partially supported by Grant-in-Aid for Scientific Research (B: 17H02995) from the Japan Society for the Promotion of Science.

  3. Intensity stability improvements for the intense pulsed neutron source accelerator system

    International Nuclear Information System (INIS)

    Rauchas, A.; Gunderson, G.; Zolecki, R.; Stipp, V.; Volk, G.

    1985-01-01

    The Intense Pulsed Neutron Source (IPNS) accelerator system consists of a 750 keV Cockcroft-Walton preaccelerator, 50 MeV linear accelerator and a 500 MeV Rapid Cycling Synchrotron (RCS). The accelerator system accelerates over 2.5 x 10 12 protons per pulse at a 30 Hz rate to strike a depleted uranium target for producing neutrons (which are used for neutron scattering research.) Since beginning operation in 1977, the beam intensity has been steadily increasing with improvements in various systems, such as a new H - source, improved correction magnet systems, etc. Instabilities created by the higher intensities have also been under control

  4. Future opportunities with pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.D. [Rutherford Appleton Lab., Chilton (United Kingdom)

    1996-05-01

    ISIS is the world`s most powerful pulsed spallation source and in the past ten years has demonstrated the scientific potential of accelerator-driven pulsed neutron sources in fields as diverse as physics, earth sciences, chemistry, materials science, engineering and biology. The Japan Hadron Project gives the opportunity to build on this development and to further realize the potential of neutrons as a microscopic probe of the condensed state. (author)

  5. A sistematical study of spallation reaction

    International Nuclear Information System (INIS)

    Foshina, M.

    1982-01-01

    A four-parameter semi-empirical formulae is proposed to calculate photo-spallation cross sections. This formulae is deduced starting from a nuclear model considered as a particle mixture without differences among them and the spallation phenomenous is considered as sucessive nucleon emission ruled by determined probability law. The formulae parameters are obtained from photo-spallation yields experimentally determined and available in literature. A variation study of the values of different parameters with the mass number of the 'seed' nucleus and incident energy is made. A parallel study for the spallation reactions induced by protons of a sampling of 720 data is also presented. (L.C.) [pt

  6. BINP pilot accelerator-based neutron source for neutron capture therapy

    International Nuclear Information System (INIS)

    Belchenko, Yuriy; Burdakov, Alexander; Davydenko, Vladimir; Ivanov, Alexander; Kobets, Valeriy; Kudryavtsev, Andrey; Savkin, Valeriy; Shirokov, Valeriy; Taskaev, Sergey

    2006-01-01

    Neutron source based on accelerator has been proposed for neutron capture therapy at hospital. Innovative approach is based upon tandem accelerator with vacuum insulation and near threshold 7 Li(p,n) 7 Be neutron generation. Pilot innovative accelerator based neutron source is under going to start operating now at BINP, Novosibirsk. Negative ion source with Penning geometry of electrodes has been manufactured and dc H - ion beam has been obtained. Study of beam transport was carried out using prototype of tandem accelerator. Tandem accelerator and ion optical channels have been manufactured and assembled. Neutron producing target has been manufactured, thermal regimes of target were studied, and lithium evaporation on target substrate was realized. In the report, the pilot facility design is given and design features of facility components are discussed. Current status of project realization, results of experiments and simulations are presented. (author)

  7. Accelerator-driven Medical Sterilization to Replace Co-60 Sources

    Energy Technology Data Exchange (ETDEWEB)

    Kroc, Thomas K. [Fermilab; Thangaraj, Jayakar C.T. [Fermilab; Penning, Richard T. [Fermilab; Kephart, Robert D. [Fermilab

    2017-08-11

    This report documents the results of a study prepared at the request of the Office of Radiological Security of the National Nuclear Security Administration (NNSA), as part of the Domestic Protect and Reduce mission by the Illinois Accelerator Research Center (IARC) of Fermi National Accelerator Laboratory. The study included a literature survey of over 80 relevant documents and articles including industry standards, regulatory documents, technical papers, a court case, previous task force reports and industry white papers. The team also conducted interviews or had conversations with over 40 individuals representing over a dozen organizations over the course of its 10-month program. This report summarizes our findings, addresses the specific questions posed to us by NNSA, and concludes with a list of actionable recommendations.

  8. Radiochemical aspects of liquid mercury spallation targets

    CERN Document Server

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

    2012-01-01

    Liquid metal spallation targets using mercury as target material are used in state-of-the-art high power pulsed neutron sources that have been constructed in the USA and Japan within the last decade. Similar target concepts were also proposed for next generation ISOL, beta-beam and neutrino facilities. A large amount of radioactivity will be induced in the liquid metal during operation caused by the interaction of the target material with the intense proton beam. This radioactivity - carried by a wide range of radioisotopes of all the elements of the periodic table from hydrogen up to thallium - must be considered for the assessment of safe operation and maintenance procedures as well as for a final disposal of the used target material and components. This report presents an overview on chemical investigations performed in our laboratory that deal with the behavior of radionuclides in proton irradiated mercury samples. The solubility of elements in mercury was calculated using thermodynamical data obtained by...

  9. Modification of 300kV RF Ion Source for 1-MV Electrostatic Accelerator at KOMAC

    International Nuclear Information System (INIS)

    Kim, Dae-Il; Kwon, Hyeok-Jung; Park, Sae-Hoon; Cho, Yong-Sub

    2015-01-01

    The specifications of the 1-MV electrostatic accelerator are shown as below. High voltage power supply is electron transformer rectifier (ELV) type which was developed in Nuclear Physics Institute (Novosibirsk) for industrial electron accelerators. And accelerator column consists of alumina and metal electrode rings were 0.5m-long brazed structure which can be installed horizontally. In case of ion source for 1-MV electrostatic accelerator, it is chosen a thonemann type rf ion source and 300-kV test-stand was made up to confirm the stable operating conditions. High voltage power supply is fabricated by domestic company, and its operation has been confirming at KOMAC site. Equally, the ion source of 300-kV test-stand should be modified to install into the high voltage power supply. In this paper, modification of ion source of 300-kV test-stand for 1-MV electrostatic accelerator is presented and its processes are considered. 300-kV RF ion source and power supply are testing for the 1-MV electrostatic accelerator and trying for combination between them. The 1-MV electrostatic accelerator will be fabricated with domestic companies and tested in the beam application research building at KOMAC

  10. Effect of irradiation in a spallation neutron environment on tensile properties and microstructure of aluminum alloys 5052 and 6061

    Energy Technology Data Exchange (ETDEWEB)

    Dunlap, J.A.; Stubbins, J.F. [Univ. of Illinois, Urbana, IL (United States); Borden, M.J.; Sommer, W.F. [Los Alamos National Lab., NM (United States)

    1996-12-31

    The Accelerator Production of Tritium (APT) and the Accelerator Transmutation of Waste (ATW) programs require structural materials which retain good mechanical properties when exposed in a spallation neutron irradiation environment. One group of materials likely to withstand the environment anticipated for these systems is the aluminum alloy series. To characterize this class of materials in a prototypical irradiation environment, AL5052 (Al-2.7Mg) and Al6061 (Al-1.1Mg-0.5Si) in hardened and annealed conditions were irradiated to a fluence of 4.2 {times} 10{sup 20} neutrons/cm{sup 2} at {approximately} 100 C in a spallation neutron source. Following irradiation, tensile tests and post-test examinations were performed to determine the influence of irradiation and test temperature on mechanical properties and fracture mode. It was found that, the properties of these two aluminum alloys were not significantly affected by the irradiation exposure conditions examined here. Thus these materials may be acceptable as structural materials for APT and ATW applications. This conclusion is based on limited mechanical properties testing, supported by other information in the literature on the performance of these materials in other irradiation environments.

  11. 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.

  12. Laser-Accelerated Proton Beams as a New Particle Source

    OpenAIRE

    Nürnberg, Frank

    2010-01-01

    The framework of this thesis is the investigation of the generation of proton beams using high-intensity laser pulses. Today's high power, ultrashort pulse laser systems are capable of achieving laser intensities up to 10^21 W/cm^2. When focused onto thin foil targets, extremely high field gradients of the order of TV/m are produced on the rear side of the target resulting in the acceleration of protons to multi-MeV energies with an exponential spectrum including up to 10^13 particles. This a...

  13. Overview of Accelerator Physics Studies and High Level Software for the Diamond Light Source

    CERN Document Server

    Bartolini, Riccardo; Belgroune, Mahdia; Christou, Chris; Holder, David J; Jones, James; Kempson, Vince; Martin, Ian; Rowland, James H; Singh, Beni; Smith, Susan L; Varley, Jennifer Anne; Wyles, Naomi

    2005-01-01

    DIAMOND is a 3 GeV synchrotron light source under construction at Rutherford Appleton Laboratory in Oxfordshire (UK). The accelerators complex consists of a 100 MeV LINAC, a full energy booster and a 3GeV storage ring with 22 straight sections available for IDs. Installation of all three accelerators has begun, and LINAC commissioning is due to start in Spring 2005. This paper will give an overview of the accelerator physics activity to produce final layouts and prepare for the commissioning of the accelerator complex. The DIAMOND facility is expected to be operational for users in 2007

  14. Laser-ablation-based ion source characterization and manipulation for laser-driven ion acceleration

    Science.gov (United States)

    Sommer, P.; Metzkes-Ng, J.; Brack, F.-E.; Cowan, T. E.; Kraft, S. D.; Obst, L.; Rehwald, M.; Schlenvoigt, H.-P.; Schramm, U.; Zeil, K.

    2018-05-01

    For laser-driven ion acceleration from thin foils (∼10 μm–100 nm) in the target normal sheath acceleration regime, the hydro-carbon contaminant layer at the target surface generally serves as the ion source and hence determines the accelerated ion species, i.e. mainly protons, carbon and oxygen ions. The specific characteristics of the source layer—thickness and relevant lateral extent—as well as its manipulation have both been investigated since the first experiments on laser-driven ion acceleration using a variety of techniques from direct source imaging to knife-edge or mesh imaging. In this publication, we present an experimental study in which laser ablation in two fluence regimes (low: F ∼ 0.6 J cm‑2, high: F ∼ 4 J cm‑2) was applied to characterize and manipulate the hydro-carbon source layer. The high-fluence ablation in combination with a timed laser pulse for particle acceleration allowed for an estimation of the relevant source layer thickness for proton acceleration. Moreover, from these data and independently from the low-fluence regime, the lateral extent of the ion source layer became accessible.

  15. Corrosion mechanism of T91 steel by Pb-Bi eutectic used as spallation target: importance for accelerator driven system; Mecanisme de corrosion de l'acier T91 par l'eutectique Pb-Bi utilise comme materiau de cible de spallation: importance pour les reacteurs hybrides

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, L

    2005-10-15

    The aim of this work has been to determine the oxidation mechanism of the martensitic steel T91 in the Pb-Bi liquid eutectic alloy, saturated in oxygen, at 470 C, in order to develop a long-term predictive model of the oxidation kinetics of the steel. This work enters in the framework of the lifetime studies of the spallation module demonstrator: MEGAPIE for the researches on hybrid reactors. An experimental characterization of the oxide layers has been carried out as well as the oxidation kinetics of the T91 steel. An oxidation mechanism has been elaborated from these experimental results and then simulated. The oxide layer formed at the T91 surface presents a duplex structure constituted by a magnetite external layer and a spinel Fe-Cr internal layer. A growth mechanism of the oxide layers has been proposed: the growth of the magnetite layer seems to be limited by the iron diffusion in the lattice of the duplex oxide layer. In parallel, an auto-regulation mechanism seems to govern the growth of the Fe-Cr spinel layer. This mechanism includes a non-limiting step of the oxygen diffusion in the oxide layer (by liquid way in the nano-channels of lead), as well as a limiting step of iron diffusion in the lattice of the oxide layer. In considering the proposed oxidation mechanisms, a simulation of the growth of the two oxide layers is carried out and compared to the long-time oxidation growth kinetics. The good agreement between the experimental results allows, finally, to strengthen the proposition of a long-term growth kinetic oxidation mechanism of the oxide layers. (O.M.)

  16. Spallation reactions studied with 4-detector arrays

    Indian Academy of Sciences (India)

    Recently there has been a renewed interest in the study of spallation reactions in basic nuclear physics as well as in potential applications. Spallation reactions induced by light projectiles (protons, antiprotons, pions, etc.) in the GeV range allow the formation of hot nuclei which do not suffer the collective excitations ...

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

    International Nuclear Information System (INIS)

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

    2001-01-01

    Calculations of the epithermal-neutron yield of photoneutrons from a uranium-beryllium converter using a 27 MeV electron linear accelerator have been investigated. In this concept, relativistic electron beams from a 30 MeV LINAC impinge upon a small uranium sphere surrounded by a cylindrical tank of circulating heavy water (D 2 O) nested in a beryllium cube. The photo-fission neutron spectrum from the uranium sphere is thermalized in deuterium and beryllium, filtered and moderated in special material (AlF 3 /Al/LiF), and directed to the patient. The results of these calculations demonstrate that photoneutron devices could offer a promising alternative to nuclear reactors for the production of epithermal neutrons for Neutron Capture Therapy. The predicted parameter for the epithermal flux is more than 10 8 n.cm -2 .mA -1

  18. Accelerating fissile material detection with a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, Mark S.; Snyderman, Neal J.

    2018-01-30

    A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly to count neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. The system includes a Poisson neutron generator for in-beam interrogation of a possible fissile neutron source and a DC power supply that exhibits electrical ripple on the order of less than one part per million. Certain voltage multiplier circuits, such as Cockroft-Walton voltage multipliers, are used to enhance the effective of series resistor-inductor circuits components to reduce the ripple associated with traditional AC rectified, high voltage DC power supplies.

  19. Neutron sources in a 24-MV medical linear accelerator.

    Science.gov (United States)

    LaRiviere, P D

    1985-01-01

    During the assembly of the prototype Clinac 2500, a unique opportunity arose to measure the cumulative total neutron yield of the machine as the major subassemblies were added, section by section. Differentiation of the results led to an inventory of the relative strength of the several neutron sources identified. The method utilized the fact that the scattered neutron fluence in a cavity in concrete is nearly uniform throughout the space and proportional to the fast neutron source strength. When normalized to the neutron output of the guide with bend magnet vacuum chamber, the relative neutron source strengths found were target, 1.9; primary collimator, 2.4; steel filter, 0.6; tungsten filter, 1.5; and jaw system, 0.8 open and approximately 2.0 closed. There is reasonable agreement between these measurements and published estimates of the yields from the major components of the treatment head.

  20. Review of MEVVA ion source performance for accelerator injection

    International Nuclear Information System (INIS)

    Brown, I.G.; Godechot, X.; Spaedtke, P.; Emig, H.; Rueck, D.M.; Wolf, B.H.

    1991-05-01

    The Mevva (metal vapor vacuum arc) ion source provides high current beams of multiply-charged metal ions suitable for use in heavy ion synchrotrons as well as for metallurgical ion implantation. Pulsed beam currents of up to several amperes can be produced at ion energies of up to several hundred keV. Operation has been demonstrate for 48 metallic ion species: Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U. When the source is operated optimally the rms fractional beam noise can be as low as 7% of the mean beam current; and when properly triggered the source operates reliably and reproducibly for many tens of thousands of pulses without failure. In this paper we review the source performance referred specifically to its use for synchrotron injection. 15 refs., 3 figs

  1. Accelerating discovery with open-source technology at eLife

    OpenAIRE

    Penfold, Naomi

    2017-01-01

    Accelerating discovery with open-source technology. Talks presented May 2017.Files can be found at https://github.com/npscience/eLife-innovation-May2017-presentation.These slides are derived from a deck shared by Jennifer McLennan. All other sources acknowledged throughout the presentation.

  2. Spectrum shaping assessment of accelerator-based fusion neutron sources to be used in BNCT treatment

    Science.gov (United States)

    Cerullo, N.; Esposito, J.; Daquino, G. G.

    2004-01-01

    Monte Carlo modelling of an irradiation facility, for boron neutron capture therapy (BNCT) application, using a set of advanced type, accelerator based, 3H(d,n) 4He (D-T) fusion neutron source device is presented. Some general issues concerning the design of a proper irradiation beam shaping assembly, based on very hard energy neutron source spectrum, are reviewed. The facility here proposed, which represents an interesting solution compared to the much more investigated Li or Be based accelerator driven neutron source could fulfil all the medical and safety requirements to be used by an hospital environment.

  3. A study on virtual source position for electron beams from a Mevatron MD linear accelerator

    International Nuclear Information System (INIS)

    Ravindran, B.P.

    1999-01-01

    The virtual source position (VSP) for electron beams of energies 5, 7, 9 10, 12 and 14 MeV and for the applicators (cones) available in the department have been measured for a Mevatron MD class linear accelerator. Different methods of obtaining the virtual source position for electron beams have been investigated in the present study. The results obtained have been compared with those of other workers. It is observed that the VSP is very much machine dependent and needs to be measured for each linear accelerator. The effect of shielding on virtual source position for the type of applicators available in the department has also been investigated. (author)

  4. Current status and future perspectives of accelerator-based x-ray light sources

    Science.gov (United States)

    Tanaka, Takashi

    2017-09-01

    State-of-the-art x-ray light sources are nowadays based on large-scale electron accelerators, because the synchrotron radiation (SR) and x-ray free electron laser (XFEL) radiation generated by high-energy electron beams have many advantages over other alternatives in terms of the wavelength tunability, high brightness and flux, high coherence, flexible polarization states, and so on. This is the reason why SR and XFEL light sources have largely contributed to the evolution of x-ray science. This paper reviews the current status of such accelerator-based x-ray light source facilities and discusses their future perspectives.

  5. Design of a high brightness ion source for the Basic Technology Accelerator (BTA)

    International Nuclear Information System (INIS)

    Okumura, Yoshikazu; Watanabe, Kazuhiro

    1992-03-01

    An ion source has been designed and fabricated for a 10 MeV, 10 mA, CW proton accelerator called Basic Technology Accelerator (BTA). The ion source consists of a multicusp plasma generator and a two-stage extractor, and is expected to produce a 100 keV, 120 mA H + ion beam with a normalized emittance of as low as 0.5 πmm.mrad. Guiding principles of the design are presented together with calculations on magnetic configuration, proton yield, plasma production, beam optics, and gas efficiency of the ion source. (author)

  6. Machine Protection: Availability for Particle Accelerators

    CERN Document Server

    Apollonio, Andrea; Schmidt, Ruediger

    2015-03-16

    Machine availability is a key indicator for the performance of the next generation of particle accelerators. Availability requirements need to be carefully considered during the design phase to achieve challenging objectives in different fields, as e.g. particle physics and material science. For existing and future High-Power facilities, such as ESS (European Spallation Source) and HL-LHC (High-Luminosity LHC), operation with unprecedented beam power requires highly dependable Machine Protection Systems (MPS) to avoid any damage-induced downtime. Due to the high complexity of accelerator systems, finding the optimal balance between equipment safety and accelerator availability is challenging. The MPS architecture, as well as the choice of electronic components, have a large influence on the achievable level of availability. In this thesis novel methods to address the availability of accelerators and their protection systems are presented. Examples of studies related to dependable MPS architectures are given i...

  7. Ultrafast terawatt laser sources for high-field particle acceleration and short wavelength generation

    International Nuclear Information System (INIS)

    Downer, M.C.

    1996-01-01

    The Laser Sources working group concerned itself with recent advances in and future requirements for the development of laser sources relevant to high-energy physics (HEP) colliders, small scale accelerators, and the generation of short wave-length radiation. We heavily emphasized pulsed terawatt peak power laser sources for several reasons. First, their development over the past five years has been rapid and multi-faceted, and has made relativistic light intensity available to the advanced accelerator community, as well as the wider physics community, for the first time. Secondly, they have strongly impacted plasma-based accelerator research over the past two years, producing the first experimental demonstrations of the laser wakefield accelerator (LWFA) in both its resonantly-driven and self-modulated forms. Thirdly, their average power and wall-plug efficiency currently fall well short of projected requirements for future accelerators and other high average power applications, but show considerable promise for improving substantially over the next few years. A review of this rapidly emerging laser technology in the context of advanced accelerator research is therefore timely

  8. Accelerators

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    The talk summarizes the principles of particle acceleration and addresses problems related to storage rings like LEP and LHC. Special emphasis will be given to orbit stability, long term stability of the particle motion, collective effects and synchrotron radiation.

  9. Neutron Imaging at Compact Accelerator-Driven Neutron Sources in Japan

    Directory of Open Access Journals (Sweden)

    Yoshiaki Kiyanagi

    2018-03-01

    Full Text Available Neutron imaging has been recognized to be very useful to investigate inside of materials and products that cannot be seen by X-ray. New imaging methods using the pulsed structure of neutron sources based on accelerators has been developed also at compact accelerator-driven neutron sources and opened new application fields in neutron imaging. The world’s first dedicated imaging instrument at pulsed neutron sources was constructed at J-PARC in Japan owing to the development of such new methods. Then, usefulness of the compact accelerator-driven neutron sources in neutron science was recognized and such facilities were newly constructed in Japan. Now, existing and new sources have been used for neutron imaging. Traditional imaging and newly developed pulsed neutron imaging such as Bragg edge transmission have been applied to various fields by using compact and large neutron facilities. Here, compact accelerator-driven neutron sources used for imaging in Japan are introduced and some of their activities are presented.

  10. Installation of an injector for SNICS source of the Tandem Accelerator

    International Nuclear Information System (INIS)

    Villasenor S, P.

    2006-01-01

    Presently work, the adaptation and installation of an accelerating tube (that operates as Injector of 75 KV), to the source of ions 'Sputtering Negative Ion Cesium Source', (SNICS), of the Tandem Accelerator EN of the Nuclear Center is presented. This work allowed to increase the acceleration energy from the negative ions to the beginning of the tank. Since the beam energy that it was possible to obtain from the source, it was very below the design parameters, what limited in great measure the reach of the experiments that could be carried out, was urgent to carry out the installation of the accelerator tube mentioned to the source. The limitations in the available resources had impeded this improvement and it took time being deferred. The added value of this adaptation, it resides in that it is a specialized work and it was, finally, carried out with success by the workers of the Accelerator, adapting to the few existent resources and achieving with it a substantial improvement of the bombing currents obtained for the samples of the investigators. (Author)

  11. The spallation neutron source: New opportunities

    Indian Academy of Sciences (India)

    ... begin operations in 2008. When complete, the facility will accommodate 25 instruments enabling researchers from the United States and abroad to study materials science that forms the basis for new technologies in telecommunications, manufacturing, transportation, information technology, biotechnology, and health.

  12. Spallation Neutron Source Superconducting Linac Commissioning Algorithms

    CERN Document Server

    Henderson, Stuart; Galambos, John; Jeon Dong Oh; Zhang, Yan

    2005-01-01

    We describe the techniques which will be employed for establishing RF and quadrupole setpoints in the SNS superconducting linac. The longitudinal tuneup will be accomplished using phase-scan methods, as well as a technique that makes use of the beam induced field in the unpowered cavity.* The scheme for managing the RF and quadrupole setpoints to achieve a given energy profile will be described.

  13. Energy dependence of isotopic spectra from spallation residues

    International Nuclear Information System (INIS)

    Audouin, L.

    2003-09-01

    Spallation reactions are collisions between heavy nuclei and light particle with an energy of a few hundreds MeV. The y are considered as a suitable way to create high- flux neutrons sources, which may used for example for the transmutation of nuclear wastes (hybrid reactors). The study of the residues from such reactions is both a way to understand the physics of the spallation and to provide information required for the design of industrial targets. The residues from the spallation of lead by proton at 500 MeV have been measured using the inverse kinematics technique in the FRS (fragments recoil separator). spectrometer from GSI (Barmstadt). This low energy required the use of new technique, for the experimental setup as well as during the analysis. The fragments were identified in-flight, prior to β decay. Complete isotopic distributions are obtained with an accuracy ranging between 10 and 30%. Detailed information on the reaction kinematics are also obtained. Data are in excellent agreement with radio-chemical measurements, and bring new insights about the spallation process. The comparison with data measured on the same system with an incident energy of 1 GeV allows to discuss the influence of the projectile energy on the residues formation. It is concluded that the independence of the shape of the isobaric production cross sections regarding mass and energy of the projectile is preserved at low incident energies. The behaviour of Monte-Carlo codes is discussed with respect to those sets of data. The calculations show an improving agreement with decreasing energy, indicating that high-energy phenomena, for which some common assumptions become questionable, are the main reason for the observed discrepancies. (author)

  14. PROMETHEUS-A: A helicon plasma source for future wakefield accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Buttenschoen, Birger; Fahrenkamp, Nils; Grulke, Olaf [Max Planck Institute for Plasma Physics, Wendelsteinstr. 1, 17491 Greifswald (Germany)

    2015-05-01

    High density plasma sources are of interest for a wide range of applications like plasma-wall interaction studies, plasma thrusters for space propulsion, or future plasma wakefield particle accelerators. In this contribution, we present a high power helicon cell designed for the world's first proton-beam driven plasma wakefield accelerator experiment AWAKE. Using a modular concept with four antennas distributed along a one meter long, five centimeter diameter prototype module providing up to 35 kW of rf power to the plasma, accelerator relevant densities of 6 . 10{sup 20} m{sup -3} are transiently achieved and exceeded. These high density plasmas are characterized for the use with wakefield accelerators, considering density evolution and its reproducibility, plasma profiles and neutral gas inventory.

  15. An accelerator neutron source for BNCT. Technical progress report, 1 June 1993--31 May 1994

    International Nuclear Information System (INIS)

    Blue, T.E.; Vafai, K.

    1994-02-01

    This is the progress report for the project entitled, ''An Accelerator Neutron Source for BNCT.'' The progress report is for the period from July 1, 1993 to date. The overall objective of our research project is to develop an Accelerator Epithermal Neutron Irradiation Facility (AENIF) for Boron Neutron Capture Therapy (BNCT). The AENIF consists of a 2.5 MeV high current proton accelerator, a lithium target to produce source neutrons, and a moderator/reflector assembly to obtain from the energetic source neutrons an epithermal neutron field suitable for BNCT treatments. Our project goals are to develop the non-accelerator components of the AENIF, and to specifically include in our development: (1) design, numerical simulation, and experimental verification of a target assembly which is capable of removing 75 kW of beam power; (2) re-optimization of the moderator assembly design based on in-phantom dose assessments using neutron spectra calculated in phantom and an energy-dependent neutron Relative Biological Effectiveness (RBE); (3) construction of a prototype moderator assembly and confirmation of its design by measurements; (4) design of the shielding of the accelerator and treatment rooms for an AENIF; and (5) design of a high energy beam transport system which is compatible with the shielding design and the thermal-hydraulic design

  16. High-current ion source development for the Korea Multipurpose Accelerator Complex

    Science.gov (United States)

    Cho, Y. S.; Choi, B. H.; Hong, I. S.; Hwang, Y. S.

    2000-02-01

    The Korea Multipurpose Accelerator Complex (KOMAC) project has been initiated to develop and build a high current proton/H- linear accelerator capable of delivering an 1 GeV cw proton beam with an intensity of 20 mA in the final stage. The major proton beam will be used for nuclear-waste transmutation, energy production, and nuclear physics experiments while utilizing the minor negative hydrogen beam for basic science research and medical therapy. A Duoplasmatron proton source for the KOMAC linear accelerator has been built at Korea Atomic Energy Research Institute. The hydrogen beam currents of up to 50 mA at the extraction voltage of 50 kV are routinely obtained. A low normalized rms emittance of 0.2 π mm mrad and a proton fraction of over 80% are obtained in this source. With the 100% duty factor of ion source operation, the arc filaments of the source have survived over 40 h. Except for the filament lifetime, the achieved parameters of the proton beam source are satisfying most requirements of the KOMAC ion source. The ion sources can extract the 10 mA nitrogen beam and 3 mA argon beam for the industrial surface modification processes.

  17. Energy dependence of isotopic spectra from spallation residues; Dependance en energie des spectres isotopiques de residus de spallation

    Energy Technology Data Exchange (ETDEWEB)

    Audouin, L

    2003-09-01

    Spallation reactions are collisions between heavy nuclei and light particle with an energy of a few hundreds MeV. The y are considered as a suitable way to create high- flux neutrons sources, which may used for example for the transmutation of nuclear wastes (hybrid reactors). The study of the residues from such reactions is both a way to understand the physics of the spallation and to provide information required for the design of industrial targets. The residues from the spallation of lead by proton at 500 MeV have been measured using the inverse kinematics technique in the FRS (fragments recoil separator). spectrometer from GSI (Barmstadt). This low energy required the use of new technique, for the experimental setup as well as during the analysis. The fragments were identified in-flight, prior to {beta} decay. Complete isotopic distributions are obtained with an accuracy ranging between 10 and 30%. Detailed information on the reaction kinematics are also obtained. Data are in excellent agreement with radio-chemical measurements, and bring new insights about the spallation process. The comparison with data measured on the same system with an incident energy of 1 GeV allows to discuss the influence of the projectile energy on the residues formation. It is concluded that the independence of the shape of the isobaric production cross sections regarding mass and energy of the projectile is preserved at low incident energies. The behaviour of Monte-Carlo codes is discussed with respect to those sets of data. The calculations show an improving agreement with decreasing energy, indicating that high-energy phenomena, for which some common assumptions become questionable, are the main reason for the observed discrepancies. (author)

  18. High-power, solid-state rf source for accelerator cavities

    International Nuclear Information System (INIS)

    Vaughan, D.R.; Mols, G.E.; Reid, D.W.; Potter, J.M.

    1985-01-01

    During the past few years the Defense and Electronics Center of Westinghouse Electric Corporation has developed a solid-state, 250-kW peak, rf amplifier for use with the SPS-40 radar system. This system has a pulse length of 60 μs and operates across the frequency band from 400 to 450 MHz. Because of the potential use of such a system as an rf source for accelerator applications, a collaborative experiment was initiated between Los Alamos National Laboratory and Westinghouse to simulate the resonant load conditions of an accelerator cavity. This paper describes the positive results of that experiment as well as the solid-state amplifier architecture. It also explores the future of high-power, solid-state amplifiers as rf sources for accelerator structures

  19. Design Considerations When Accelerating an FPGA-Based Digital Microphone Array for Sound-Source Localization

    Directory of Open Access Journals (Sweden)

    Bruno da Silva

    2017-01-01

    Full Text Available The use of microphone arrays for sound-source localization is a well-researched topic. The response of such sensor arrays is dependent on the quantity of microphones operating on the array. A higher number of microphones, however, increase the computational demand, making real-time response challenging. In this paper, we present a Filter-and-Sum based architecture and several acceleration techniques to provide accurate sound-source localization in real-time. Experiments demonstrate how an accurate sound-source localization is obtained in a couple of milliseconds, independently of the number of microphones. Finally, we also propose different strategies to further accelerate the sound-source localization while offering increased angular resolution.

  20. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Mitchell, H.E.

    1996-04-01

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 10 7 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF 3 composite and a stacked Al/Teflon design) at various incident electron energies

  1. An accelerator-based epithermal photoneutron source for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Hannah E. [Georgia Inst. of Technology, Atlanta, GA (United States)

    1996-04-01

    Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 107 neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF3 composite and a stacked Al/Teflon design) at various incident electron energies.

  2. Accelerating the commercialization on new technologies. [free market operation of federal alternate energy sources programs

    Science.gov (United States)

    Kuehn, T. J.; Nawrocki, P. M.

    1978-01-01

    It is suggested that federal programs for hastening the adoption of alternative energy sources must operate within the free market structure. Five phases of the free market commercialization process are described. Federal role possibilities include information dissemination and funding to stimulate private sector activities within these five phases, and federally sponsored procedures for accelerating commercialization of solar thermal small power systems are considered.

  3. Monte Carlo studies in accelerator-driven systems for transmutation of high-level nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Sarer, Basar [Gazi Universitesi Fen-Edebiyat Fakueltesi Fizik Boeluemue, Besevler, Ankara (Turkey)], E-mail: sarer@gazi.edu.tr; Korkmaz, M. Emin [Gazi Universitesi Fen-Edebiyat Fakueltesi Fizik Boeluemue, Besevler, Ankara (Turkey); Guenay, Mehtap [Inoenue Universitesi Fen-Edebiyat Fakueltesi Fizik Boeluemue, Malatya (Turkey); Aydin, Abdullah [Kirikkale Universitesi Fen-Edebiyat Fakueltesi Fizik Boeuemue, Kirikkale (Turkey)

    2008-07-15

    A spallation neutron source was modeled using a high energy proton accelerator for transmutation of {sup 239}Pu, minor actinides {sup 237}Np, {sup 241}Am and long-lived fission products {sup 99}Tc, {sup 129}I, which are created from the operation of nuclear power reactors for the production of electricity. The acceleration driven system (ADS) is composed of a natural lead target, beam window, subcritical core, reflector, and structural material. The neutrons are produced by the spallation reaction of protons from a high intensity linear accelerator in the spallation target, and the fission reaction in the core. It is used a hexagonal lattice for the waste and fuel assemblies. The system is driven by a 1 GeV, 10 mA proton beam incident on a natural lead cylindrical target. The protons were uniformly distributed across the beam. The core is a cylindrical assembly. The main vessel is surrounded by a reflector made of graphite. The axes of the proton beam and the target are concentric with the main vessel axis. The structural walls and the beam window are made of the same material, stainless steel, HT9. We investigated the following neutronics parameters: spallation neutron and proton yields, spatial and energy distribution of the spallation neutrons, and protons, heat deposition, and the production rates of hydrogen and helium, transmutation rate of minor actinides and fission products. In the calculations, the Monte Carlo code MCNPX, which is a combination of LAHET and MCNP, was used. To transport a wide variety of particles, The Los Alamos High Energy Transport Code (LAHET) was used.

  4. 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)

  5. Magnetic field design for a Penning ion source for a 200 keV electrostatic accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Fathi, A., E-mail: Atefeh.Fathi115@gmail.com [Radiation Applications Department, Shahid Beheshti University, G. C., Tehran (Iran, Islamic Republic of); Feghhi, S.A.H.; Sadati, S.M. [Radiation Applications Department, Shahid Beheshti University, G. C., Tehran (Iran, Islamic Republic of); Ebrahimibasabi, E. [Department of Physics, Shahrood University of Technology, 3619995161, Shahrood (Iran, Islamic Republic of)

    2017-04-01

    In this study, the structure of magnetic field for a Penning ion source has been designed and constructed with the use of permanent magnets. The ion source has been designed and constructed for a 200 keV electrostatic accelerator. With using CST Studio Suite, the magnetic field profile inside the ion source was simulated and an appropriate magnetic system was designed to improve particle confinement. Designed system consists of two ring magnets with 9 mm distance from each other around the anode. The ion source was constructed and the cylindrical magnet and designed magnetic system were tested on the ion source. The results showed that the ignition voltage for ion source with the designed magnetic system is almost 300 V lower than the ion source with the cylindrical magnet. Better particle confinement causes lower voltage discharge to occur.

  6. Interlaboratory study of the ion source memory effect in 36Cl accelerator mass spectrometry

    Science.gov (United States)

    Pavetich, Stefan; Akhmadaliev, Shavkat; Arnold, Maurice; Aumaître, Georges; Bourlès, Didier; Buchriegler, Josef; Golser, Robin; Keddadouche, Karim; Martschini, Martin; Merchel, Silke; Rugel, Georg; Steier, Peter

    2014-06-01

    Understanding and minimization of contaminations in the ion source due to cross-contamination and long-term memory effect is one of the key issues for accurate accelerator mass spectrometry (AMS) measurements of volatile elements. The focus of this work is on the investigation of the long-term memory effect for the volatile element chlorine, and the minimization of this effect in the ion source of the Dresden accelerator mass spectrometry facility (DREAMS). For this purpose, one of the two original HVE ion sources at the DREAMS facility was modified, allowing the use of larger sample holders having individual target apertures. Additionally, a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, an interlaboratory comparison had been initiated. The long-term memory effect of the four Cs sputter ion sources at DREAMS (two sources: original and modified), ASTER (Accélérateur pour les Sciences de la Terre, Environnement, Risques) and VERA (Vienna Environmental Research Accelerator) had been investigated by measuring samples of natural 35Cl/37Cl-ratio and samples highly-enriched in 35Cl (35Cl/37Cl ∼ 999). Besides investigating and comparing the individual levels of long-term memory, recovery time constants could be calculated. The tests show that all four sources suffer from long-term memory, but the modified DREAMS ion source showed the lowest level of contamination. The recovery times of the four ion sources were widely spread between 61 and 1390 s, where the modified DREAMS ion source with values between 156 and 262 s showed the fastest recovery in 80% of the measurements.

  7. Constraining sources of ultrahigh energy cosmic rays and shear acceleration mechanism of particles in relativistic jets

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ruoyu

    2015-06-10

    Ultrahigh energy cosmic rays are extreme energetic particles from outer space. They have aroused great interest among scientists for more than fifty years. However, due to the rarity of the events and complexity of the process of their propagation to Earth, they are still one of the biggest puzzles in modern high energy astrophysics. This dissertation is dedicated to study the origin of ultrahigh energy cosmic rays from various aspects. Firstly, we discuss a possible link between recently discovered sub-PeV/PeV neutrinos and ultrahigh energy cosmic rays. If these two kinds of particles share the same origin, the observation of neutrinos may provide additional and non-trivial constraints on the sources of ultrahigh energy cosmic rays. Secondly, we jointly employ the chemical composition measurement and the arrival directions of ultrahigh energy cosmic rays, and find a robust upper limit for distances of sources of ultrahigh energy cosmic rays above ∝55 EeV, as well as a lower limit for their metallicities. Finally, we study the shear acceleration mechanism in relativistic jets, which is a more efficient mechanism for the acceleration of higher energy particle. We compute the acceleration efficiency and the time-dependent particle energy spectrum, and explore the feature of synchrotron radiation of the accelerated particles. The possible realizations of this mechanism for acceleration of ultrahigh energy cosmic rays in different astrophysical environments is also discussed.

  8. Multilevel acceleration of scattering-source iterations with application to electron transport

    Directory of Open Access Journals (Sweden)

    Clif Drumm

    2017-09-01

    Full Text Available Acceleration/preconditioning strategies available in the SCEPTRE radiation transport code are described. A flexible transport synthetic acceleration (TSA algorithm that uses a low-order discrete-ordinates (SN or spherical-harmonics (PN solve to accelerate convergence of a high-order SN source-iteration (SI solve is described. Convergence of the low-order solves can be further accelerated by applying off-the-shelf incomplete-factorization or algebraic-multigrid methods. Also available is an algorithm that uses a generalized minimum residual (GMRES iterative method rather than SI for convergence, using a parallel sweep-based solver to build up a Krylov subspace. TSA has been applied as a preconditioner to accelerate the convergence of the GMRES iterations. The methods are applied to several problems involving electron transport and problems with artificial cross sections with large scattering ratios. These methods were compared and evaluated by considering material discontinuities and scattering anisotropy. Observed accelerations obtained are highly problem dependent, but speedup factors around 10 have been observed in typical applications.

  9. Accelerator development programme in India - an outlook

    International Nuclear Information System (INIS)

    Bhandari, R.K.

    2011-01-01

    With the construction of the VEC, Indus-1, Indus-2, superconducting cyclotron, superconducting heavy ion linac boosters etc. and implementation of other accelerator R and D programmes, we are now 'equipped' to take a quantum jump in the accelerator field. We have highly trained and skilled manpower that can take up challenges in this rapidly growing field both for research as well as applications. Serious planning is going on in the country to construct accelerator facilities for versatile Rare Ion Beams (RIB), powerful spallation source, advanced synchrotron source, high power beam for ADS etc. There is strong demand by the medical community for a proton/heavy ion cancer therapy facility and for accelerator-produced radioisotopes for medical diagnostics. Proliferation of accelerators in the industry field is long overdue in our country and welcome realization is coming. In this presentation a glimpse of the intended growth of accelerator field in the country will be given. Interesting challenges are there not only for the accelerator community, which has to grow, but also for the industry. Since the general trend is now to construct high intensity and high beam power accelerators - both for research as well as applications - the associated problems of radiation safety will be highlighted. (author)

  10. Recent progress in accelerator activities at Raja Ramanna Centre for Advanced Technology, Indore

    International Nuclear Information System (INIS)

    Gupta, P.D.

    2013-01-01

    Raja Ramanna Centre for Advanced Technology, Indore is a premier national institute engaged in R and D work in front-line areas of accelerator science, technology, and applications. The Centre has designed, developed, and commissioned two synchrotron radiation sources: Indus-1 and Indus-2, serving as national facilities. The Centre is pursuing various other accelerator activities viz. development of a high energy proton accelerator for a spallation neutron source, electron accelerators for food irradiation and industrial applications and free electron lasers (FEL) in THz and IR spectral region, study of innovative schemes of laser driven electron acceleration, and development of advanced technologies to support these activities such as superconducting RF (SCRF) technology, cryogenics, RF power, magnets, ultra high vacuum and control instrumentation. In this talk, an overview of the progress made in accelerator activities at Raja Ramanna Centre for Advanced Technology in recent years is be presented

  11. A French proposal for an innovative accelerators based coherent UV-X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Couprie, M.E. E-mail: marie-emmanuelle.couprie@lure.u-psud.fr; Belakhovsky, M.; Gilquin, B.; Garzella, D.; Jablonka, M.; Meot, F.; Monot, P.; Mosnier, A.; Nahon, L.; Rousse, A

    2004-08-01

    At the initiative of the CEA (Commissariat a l'Energie Atomique), discussions were conducted in France on fourth generation light sources. A new independent accelerator based radiation facility ARC-EN-CIEL (Accelerator Radiation Complex for ENhanced Coherent Intense Extended Light) is proposed, aiming at providing coherent femtosecond light pulses in the UV- to X-ray range for scientific applications. The project is based on a 700 MeV superconducting LINAC, providing low emittance 200 fs RMS electron bunches. They can be injected in undulators used in the Self Amplified Spontaneous Emission mode (SASE), or in the High Gain Harmonic Generation (HGHG), seeded with high harmonics in gases at 20 nm.The SASE source covers the 100-5 nm spectral range, the HGHG goes down to 0.8 nm.Two optional loops, for Energy Recovery or energy enhancement (1.4 GeV), will accommodate fs synchrotron radiation sources in the IR-, VUV- and X-ray ranges, together with a FEL oscillator providing radiation down to 10 nm, taking advantage of the optical development for lithography. The facility also proposes to test plasma acceleration and to provide a Thomson radiation source. Characteristics of the light source will be described.

  12. A French proposal for an innovative accelerators based coherent UV-X-ray source

    Science.gov (United States)

    Couprie, M. E.; Belakhovsky, M.; Gilquin, B.; Garzella, D.; Jablonka, M.; Méot, F.; Monot, P.; Mosnier, A.; Nahon, L.; Rousse, A.

    2004-08-01

    At the initiative of the CEA (Commissariat à l'Énergie Atomique), discussions were conducted in France on fourth generation light sources. A new independent accelerator based radiation facility ARC-EN-CIEL (Accelerator Radiation Complex for ENhanced Coherent Intense Extended Light) is proposed, aiming at providing coherent femtosecond light pulses in the UV- to X-ray range for scientific applications. The project is based on a 700 MeV superconducting LINAC, providing low emittance 200 fs RMS electron bunches. They can be injected in undulators used in the Self Amplified Spontaneous Emission mode (SASE), or in the High Gain Harmonic Generation (HGHG), seeded with high harmonics in gases at 20 nm.The SASE source covers the 100-5 nm spectral range, the HGHG goes down to 0.8 nm.Two optional loops, for Energy Recovery or energy enhancement (1.4 GeV), will accommodate fs synchrotron radiation sources in the IR-, VUV- and X-ray ranges, together with a FEL oscillator providing radiation down to 10 nm, taking advantage of the optical development for lithography. The facility also proposes to test plasma acceleration and to provide a Thomson radiation source. Characteristics of the light source will be described.

  13. Modification to the accelerator of the NBI-1B ion source for improving the injection efficiency

    International Nuclear Information System (INIS)

    Kim, T. S.; Jeong, S. H.; Chang, D. H.; In, S. R.; Park, M.; Jung, B. K.; Lee, K. W.; Wang, S. J.; Bae, Y. S.; Park, H. T.; Kim, J. S.; Cho, W.; Choi, D. J.

    2016-01-01

    Minimizing power loss of a neutral beam imposes modification of the accelerator of the ion source for further improvement of the beam optics. The beam optics can be improved by focusing beamlets. The injection efficiencies by the steering of ion beamlets are investigated numerically to find the optimum modification of the accelerator design of the NBI-1B ion source. The beam power loss was reduced by aperture displacement of three edge beamlets arrays considering power loadings on the beamline components. Successful testing and operation of the ion source at 60 keV/84% of injection efficiency led to the possibility of enhancing the system capability to a 2.4 MW power level at 100 keV/1.9 μP

  14. A shielding design for an accelerator-based neutron source for boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, A.E.; Blue, T.E. E-mail: blue.1@osu.edu; Woollard, J.E

    2004-11-01

    Research in boron neutron capture therapy (BNCT) at The Ohio State University Nuclear Engineering Department has been primarily focused on delivering a high quality neutron field for use in BNCT using an accelerator-based neutron source (ABNS). An ABNS for BNCT is composed of a proton accelerator, a high-energy beam transport system, a {sup 7}Li target, a target heat removal system (HRS), a moderator assembly, and a treatment room. The intent of this paper is to demonstrate the advantages of a shielded moderator assembly design, in terms of material requirements necessary to adequately protect radiation personnel located outside a treatment room for BNCT, over an unshielded moderator assembly design.

  15. A modification to the ion source pulsing system of a PN-400 Van de Graaff accelerator

    Science.gov (United States)

    Coelho, P. R. P.; Holland, L.; Sgambatti, A.

    1981-01-01

    Simple modifications to the pulsing system of a PN-400 Van de Graaff accelerator are described. An LED at ground is driven by a low power pulse generator and is coupled to a photosensitive transistor (PST) in the high tension terminal using a perspex light guide. After suitable signal amplification, the output from the PST is used to switch the ion source RF generator. Monitoring of the ion source light intensity is effected by using a second PST at ground coupled to the ion source using a second perspex light guide.

  16. US-Japan IEC Workshop on Small Plasma and Accelerator Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Miley, George H. [Univ. of Illinois, Champaign, IL (United States). Dept. of Nuclear, Plasma, and Radiological Engineering

    2007-05-25

    This report lays out the agenda for the entire workshop and then lists the abstracts for all 29 presentations. All of these presentations cover small plasma and accelerator neutron sources. A few of the presentations include: Comments about IEC History and Future Directions; Characteristics in Pulse Operation of IEC Device with Confronting Two Plasma Sources; Overview of the University of Wisconsin-Madison IEC Program; Improving IEC Particle Confinement Times Using Multiple Grids; Integral Transport Approach for Molecular Ion Processes in IEC Devices; A Counter Stream Beam D-D Neutron Generator; Low Pressure IECF Operation Using Differentially-Pumped Ion Sources, and more.

  17. High-intensity ion sources for accelerators with emphasis on H- beam formation and transport (invited)

    International Nuclear Information System (INIS)

    Keller, R.

    2010-01-01

    This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as dc discharge-driven and rf-driven multicusp sources, Penning-type, and electron cyclotron resonance-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber, and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed, ionization mechanism, beam formation, and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail.

  18. Railguns and plasma accelerators: arc armatures, pulse power sources and US patents

    International Nuclear Information System (INIS)

    Friedrich, O.M. Jr.

    1980-11-01

    Railguns and plasma accelerators have the potential for use in many basic and applied research projects, such as in creating high-pressures for equation-of-state studies and in impact fusion. A brief review of railguns and plasma accelerators with references is presented. Railgun performance is critically dependent on armature operation. Plasma arc railgun armatures are addressed. Pulsed power supplies for multi-stage railguns are considered. This includes brief comments on the compensated pulsed alternator, or compulsator, rotating machinery, and distributed energy sources for railguns. References are given at the end of each section. Appendix A contains a brief review of the US Patents on multi-staging techniques for electromagnetic accelerators, plasma propulsion devices, and electric guns

  19. Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.

    Science.gov (United States)

    Blue, Thomas E; Yanch, Jacquelyn C

    2003-01-01

    This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and

  20. Nuclear spallation of cosmic ray nuclei in the interstellar medium

    International Nuclear Information System (INIS)

    Raisbeck, G.

    1974-01-01

    Nuclear spallation of cosmic rays during propagation is qualitatively reviewed. After the problem is defined, a discussion is presented of the relevant information obtainable from studying nuclear reactions, specifically, quantity and distribution of traversed matter, time and place of propagation, and source composition. Comments are offered on the cross sections and nuclear reactions that are critical for a complete understanding in this area. This is followed by a brief look at the present status of research and possibilities for further work using the Bevalac. (U.S.)

  1. Microgan ECR ion source in a Van de Graaff accelerator terminal

    International Nuclear Information System (INIS)

    Gaubert, G.; Tasset-Maye, O.; Villari, A.C.C.; Bieth, C.; Bougy, W.; Brionne, N.; Donzel, X.; Sineau, A.; Vallerand, C.; Chaves, C.; Gamboni, T.; Geerts, W.; Giorginis, G.; Jaime Tornin, R.; Loevestam, G.; Mondelaers, W.

    2012-01-01

    The Van de Graaff accelerator at IRMM (Institute for Reference Materials and Measurements, Geel - Belgium) works since many years providing proton, deuteron and helium beams for nuclear data measurements. The original ion source was of RF type with quartz bottle. This kind of source, as well known, needs regular maintenance for which the accelerator tank must be completely opened. The heavy usage at high currents of the IRMM accelerator necessitated an opening about once every month. Recently, the full permanent magnet Microgan ECR ion source from PANTECHNIK was installed into a new terminal platform together with a solid state amplifier of 50 W, a dedicated dosing system for 4 gases (with respective gas bottles H 2 , D 2 , He and Ar), and a set of dedicated power supplies and electronic devices for the remote tuning of the source. The new system shows a very stable behaviour of the produced beam allowing running the Van de Graaff without maintenance for several months. The paper is followed by the associated poster. (authors)

  2. AMS of heavy elements with an ECR ion source and the ATLAS linear accelerator

    CERN Document Server

    Paul, M; Ahmad, I; Borasi, F; Caggiano, J; Davids, C N; Greene, J P; Harss, B; Heinz, A; Henderson, D J; Henning, W F; Jiang, C L; Pardo, R C; Rehm, K E; Rejoub, R; Seweryniak, D; Sonzogni, A; Uusitalo, J; Vondrasek, R C

    2000-01-01

    Detection of heavy elements by accelerator mass spectrometry with the electron cyclotron resonance ion source, Argonne linear accelerator and fragment mass analyzer (ECRIS-ATLAS-FMA) system has been developed. The use of the ECR-ATLAS system for AMS of heavy elements has two interesting features: (i) the efficient production of high-charge state ions in the ECR source ensures the elimination of molecular ions at the source stage, a highly attractive feature for any mass-spectrometric use not exploited so far; (ii) the linear acceleration based on velocity matching and the beam transport system act as a powerful mass filter for background suppression. We have shown that our system reaches an abundance sensitivity of 1x10 sup - sup 1 sup 4 for Pb isotopes. The sup 2 sup 3 sup 6 U detection sensitivity is sup 2 sup 3 sup 6 U/U > or approx. 1x10 sup - sup 1 sup 2 , limited mainly by the ion source output.

  3. Interlaboratory study of the ion source memory effect in 36Cl accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Pavetich, Stefan; Akhmadaliev, Shavkat; Arnold, Maurice; Aumaître, Georges; Bourlès, Didier; Buchriegler, Josef; Golser, Robin; Keddadouche, Karim; Martschini, Martin; Merchel, Silke; Rugel, Georg; Steier, Peter

    2014-01-01

    Highlights: • Long-term memory effect in negative ion sources investigated for chlorine isotopes. • Interlaboratory comparison of four up-to date negative ion sources. • Ion source improvement at DREAMS for minimization of long-term memory effect. • Long-term memory effect is the limitation for precise AMS data of volatile elements. • Findings to be considered for samples with highly variable ratios of 36 Cl/Cl and 129 I/I. - Abstract: Understanding and minimization of contaminations in the ion source due to cross-contamination and long-term memory effect is one of the key issues for accurate accelerator mass spectrometry (AMS) measurements of volatile elements. The focus of this work is on the investigation of the long-term memory effect for the volatile element chlorine, and the minimization of this effect in the ion source of the Dresden accelerator mass spectrometry facility (DREAMS). For this purpose, one of the two original HVE ion sources at the DREAMS facility was modified, allowing the use of larger sample holders having individual target apertures. Additionally, a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, an interlaboratory comparison had been initiated. The long-term memory effect of the four Cs sputter ion sources at DREAMS (two sources: original and modified), ASTER (Accélérateur pour les Sciences de la Terre, Environnement, Risques) and VERA (Vienna Environmental Research Accelerator) had been investigated by measuring samples of natural 35 Cl/ 37 Cl-ratio and samples highly-enriched in 35 Cl ( 35 Cl/ 37 Cl ∼ 999). Besides investigating and comparing the individual levels of long-term memory, recovery time constants could be calculated. The tests show that all four sources suffer from long-term memory, but the modified DREAMS ion source showed the lowest level of contamination. The recovery times of the four ion sources were widely spread between

  4. Interlaboratory study of the ion source memory effect in {sup 36}Cl accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pavetich, Stefan, E-mail: s.pavetich@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01314 Dresden (Germany); Akhmadaliev, Shavkat [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01314 Dresden (Germany); Arnold, Maurice; Aumaître, Georges; Bourlès, Didier [Aix-Marseille Université, CEREGE CNRS-IRD, F-13545 Aix-en-Provence (France); Buchriegler, Josef [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01314 Dresden (Germany); University of Vienna, Faculty of Physics, VERA Laboratory, Währingerstraße 17, 1090 Vienna (Austria); Golser, Robin [University of Vienna, Faculty of Physics, VERA Laboratory, Währingerstraße 17, 1090 Vienna (Austria); Keddadouche, Karim [Aix-Marseille Université, CEREGE CNRS-IRD, F-13545 Aix-en-Provence (France); Martschini, Martin [University of Vienna, Faculty of Physics, VERA Laboratory, Währingerstraße 17, 1090 Vienna (Austria); Merchel, Silke; Rugel, Georg [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01314 Dresden (Germany); Steier, Peter [University of Vienna, Faculty of Physics, VERA Laboratory, Währingerstraße 17, 1090 Vienna (Austria)

    2014-06-01

    Highlights: • Long-term memory effect in negative ion sources investigated for chlorine isotopes. • Interlaboratory comparison of four up-to date negative ion sources. • Ion source improvement at DREAMS for minimization of long-term memory effect. • Long-term memory effect is the limitation for precise AMS data of volatile elements. • Findings to be considered for samples with highly variable ratios of {sup 36}Cl/Cl and {sup 129}I/I. - Abstract: Understanding and minimization of contaminations in the ion source due to cross-contamination and long-term memory effect is one of the key issues for accurate accelerator mass spectrometry (AMS) measurements of volatile elements. The focus of this work is on the investigation of the long-term memory effect for the volatile element chlorine, and the minimization of this effect in the ion source of the Dresden accelerator mass spectrometry facility (DREAMS). For this purpose, one of the two original HVE ion sources at the DREAMS facility was modified, allowing the use of larger sample holders having individual target apertures. Additionally, a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, an interlaboratory comparison had been initiated. The long-term memory effect of the four Cs sputter ion sources at DREAMS (two sources: original and modified), ASTER (Accélérateur pour les Sciences de la Terre, Environnement, Risques) and VERA (Vienna Environmental Research Accelerator) had been investigated by measuring samples of natural {sup 35}Cl/{sup 37}Cl-ratio and samples highly-enriched in {sup 35}Cl ({sup 35}Cl/{sup 37}Cl ∼ 999). Besides investigating and comparing the individual levels of long-term memory, recovery time constants could be calculated. The tests show that all four sources suffer from long-term memory, but the modified DREAMS ion source showed the lowest level of contamination. The recovery times of the four ion

  5. Stabilization of ion source operation for the ''EG-2.5'' electrostatic accelerator

    International Nuclear Information System (INIS)

    Nikitin, V.A.; Yakushev, V.P.

    1980-01-01

    A system for stabilization of operating conditions of an electrostatic accelerator ion source is described. The system is the first stage of stabilizing the ion current on a target. The current of the beam escaping from a source is equal to the difference between the currents in the source anode and cathode circuits. In the anode circuit the current is stabilized by changing the HF-generator anode voltage, and the cathode current is stabilized by a special automatic device. This ensures the constancy of the current for a beam which escapes from the source and thus increases the stability of ion currents on a target. The range of current control in the source anode circuit constitutes 15-110 μA, current oscillations do not exceed 0.5% during two hours [ru

  6. Predicting induced radioactivity for the accelerator operations at the Taiwan Photon Source.

    Science.gov (United States)

    Sheu, R J; Jiang, S H

    2010-12-01

    This study investigates the characteristics of induced radioactivity due to the operations of a 3-GeV electron accelerator at the Taiwan Photon Source (TPS). According to the beam loss analysis, the authors set two representative irradiation conditions for the activation analysis. The FLUKA Monte Carlo code has been used to predict the isotope inventories, residual activities, and remanent dose rates as a function of time. The calculation model itself is simple but conservative for the evaluation of induced radioactivity in a light source facility. This study highlights the importance of beam loss scenarios and demonstrates the great advantage of using FLUKA in comparing the predicted radioactivity with corresponding regulatory limits. The calculated results lead to the conclusion that, due to fairly low electron consumption, the radioactivity induced in the accelerator components and surrounding concrete walls of the TPS is rather moderate and manageable, while the possible activation of air and cooling water in the tunnel and their environmental releases are negligible.

  7. Simulation of diatomic gas-wall interaction and accommodation coefficients for negative ion sources and accelerators

    International Nuclear Information System (INIS)

    Sartori, E.; Serianni, G.; Brescaccin, L.

    2016-01-01

    Particle-wall interactions determine in different ways the operating conditions of plasma sources, ion accelerators, and beams operating in vacuum. For instance, a contribution to gas heating is given by ion neutralization at walls; beam losses and stray particle production—detrimental for high current negative ion systems such as beam sources for fusion—are caused by collisional processes with residual gas, with the gas density profile that is determined by the scattering of neutral particles at the walls. This paper shows that Molecular Dynamics (MD) studies at the nano-scale can provide accommodation parameters for gas-wall interactions, such as the momentum accommodation coefficient and energy accommodation coefficient: in non-isothermal flows (such as the neutral gas in the accelerator, coming from the plasma source), these affect the gas density gradients and influence efficiency and losses in particular of negative ion accelerators. For ideal surfaces, the computation also provides the angular distribution of scattered particles. Classical MD method has been applied to the case of diatomic hydrogen molecules. Single collision events, against a frozen wall or a fully thermal lattice, have been simulated by using probe molecules. Different modelling approximations are compared

  8. Simulation of diatomic gas-wall interaction and accommodation coefficients for negative ion sources and accelerators

    Science.gov (United States)

    Sartori, E.; Brescaccin, L.; Serianni, G.

    2016-02-01

    Particle-wall interactions determine in different ways the operating conditions of plasma sources, ion accelerators, and beams operating in vacuum. For instance, a contribution to gas heating is given by ion neutralization at walls; beam losses and stray particle production—detrimental for high current negative ion systems such as beam sources for fusion—are caused by collisional processes with residual gas, with the gas density profile that is determined by the scattering of neutral particles at the walls. This paper shows that Molecular Dynamics (MD) studies at the nano-scale can provide accommodation parameters for gas-wall interactions, such as the momentum accommodation coefficient and energy accommodation coefficient: in non-isothermal flows (such as the neutral gas in the accelerator, coming from the plasma source), these affect the gas density gradients and influence efficiency and losses in particular of negative ion accelerators. For ideal surfaces, the computation also provides the angular distribution of scattered particles. Classical MD method has been applied to the case of diatomic hydrogen molecules. Single collision events, against a frozen wall or a fully thermal lattice, have been simulated by using probe molecules. Different modelling approximations are compared.

  9. Conceptual Design of Dielectric Accelerating Structures for Intense Neutron and Monochromatic X-ray Sources

    Science.gov (United States)

    Blanovsky, Anatoly

    2004-12-01

    Bright compact photon sources, which utilize electron beam interaction with periodic structures, may benefit a broad range of medical, industrial and scientific applications. A class of dielectric-loaded periodic structures for hard and soft X-ray production has been proposed that would provide a high accelerating gradient when excited by an external RF and/or primary electron beam. Target-distributed accelerators (TDA), in which an additional electric field compensates for lost beam energy in internal targets, have been shown to provide the necessary means to drive a high flux subcritical reactor (HFSR) for nuclear waste transmutation. The TDA may also be suitable for positron and nuclear isomer production, X-ray lithography and monochromatic computer tomography. One of the early assumptions of the theory of dielectric wake-field acceleration was that, in electrodynamics, the vector potential was proportional to the scalar potential. The analysis takes into consideration a wide range of TDA design aspects including the wave model of observed phenomena, a layered compound separated by a Van der Waals gap and a compact energy source based on fission electric cells (FEC) with a multistage collector. The FEC is a high-voltage power source that directly converts the kinetic energy of the fission fragments into electrical potential of about 2MV.

  10. Simulation of diatomic gas-wall interaction and accommodation coefficients for negative ion sources and accelerators.

    Science.gov (United States)

    Sartori, E; Brescaccin, L; Serianni, G

    2016-02-01

    Particle-wall interactions determine in different ways the operating conditions of plasma sources, ion accelerators, and beams operating in vacuum. For instance, a contribution to gas heating is given by ion neutralization at walls; beam losses and stray particle production-detrimental for high current negative ion systems such as beam sources for fusion-are caused by collisional processes with residual gas, with the gas density profile that is determined by the scattering of neutral particles at the walls. This paper shows that Molecular Dynamics (MD) studies at the nano-scale can provide accommodation parameters for gas-wall interactions, such as the momentum accommodation coefficient and energy accommodation coefficient: in non-isothermal flows (such as the neutral gas in the accelerator, coming from the plasma source), these affect the gas density gradients and influence efficiency and losses in particular of negative ion accelerators. For ideal surfaces, the computation also provides the angular distribution of scattered particles. Classical MD method has been applied to the case of diatomic hydrogen molecules. Single collision events, against a frozen wall or a fully thermal lattice, have been simulated by using probe molecules. Different modelling approximations are compared.

  11. Toward high-efficiency and detailed Monte Carlo simulation study of the granular flow spallation target

    Science.gov (United States)

    Cai, Han-Jie; Zhang, Zhi-Lei; Fu, Fen; Li, Jian-Yang; Zhang, Xun-Chao; Zhang, Ya-Ling; Yan, Xue-Song; Lin, Ping; Xv, Jian-Ya; Yang, Lei

    2018-02-01

    The dense granular flow spallation target is a new target concept chosen for the Accelerator-Driven Subcritical (ADS) project in China. For the R&D of this kind of target concept, a dedicated Monte Carlo (MC) program named GMT was developed to perform the simulation study of the beam-target interaction. Owing to the complexities of the target geometry, the computational cost of the MC simulation of particle tracks is highly expensive. Thus, improvement of computational efficiency will be essential for the detailed MC simulation studies of the dense granular target. Here we present the special design of the GMT program and its high efficiency performance. In addition, the speedup potential of the GPU-accelerated spallation models is discussed.

  12. Ion source using a hollow cathode discharge system and especially, particle accelerator comprising said source

    International Nuclear Information System (INIS)

    Mourier, Georges.

    1975-01-01

    An ion source provided with a hollow cathode discharge system is presented. The ion extraction system is designed in view of generating a beam directed towards a point of use located far from the point of ion production. Said source essentially comprises two cathodes facing each other, an anode at a continuous voltage with respect to the cathodes, a heated filament beyond the cathode on the path of the extracted beam, and a grid between said filament and cathode. The ion extraction is limited to a certain portion of the ions present inside the plasma, so as the discharge to continue to be sustained by itself. For that purpose pierced cathodes are used, with a transparency (the ratio of the hole area to the whole cathode area) not much higher than 50% [fr

  13. A review of ion sources for medical accelerators (invited)a)

    Science.gov (United States)

    Muramatsu, M.; Kitagawa, A.

    2012-02-01

    There are two major medical applications of ion accelerators. One is a production of short-lived isotopes for radionuclide imaging with positron emission tomography and single photon emission computer tomography. Generally, a combination of a source for negative ions (usually H- and/or D-) and a cyclotron is used; this system is well established and distributed over the world. Other important medical application is charged-particle radiotherapy, where the accelerated ion beam itself is being used for patient treatment. Two distinctly different methods are being applied: either with protons or with heavy-ions (mostly carbon ions). Proton radiotherapy for deep-seated tumors has become widespread since the 1990s. The energy and intensity are typically over 200 MeV and several 1010 pps, respectively. Cyclotrons as well as synchrotrons are utilized. The ion source for the cyclotron is generally similar to the type for production of radioisotopes. For a synchrotron, one applies a positive ion source in combination with an injector linac. Carbon ion radiotherapy awakens a worldwide interest. About 6000 cancer patients have already been treated with carbon beams from the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan. These clinical results have clearly verified the advantages of carbon ions. Heidelberg Ion Therapy Center and Gunma University Heavy Ion Medical Center have been successfully launched. Several new facilities are under commissioning or construction. The beam energy is adjusted to the depth of tumors. It is usually between 140 and 430 MeV/u. Although the beam intensity depends on the irradiation method, it is typically several 108 or 109 pps. Synchrotrons are only utilized for carbon ion radiotherapy. An ECR ion source supplies multi-charged carbon ions for this requirement. Some other medical applications with ion beams attract developer's interests. For example, the several types of accelerators are under

  14. Brilliant radiation sources by laser-plasma accelerators and optical undulators

    Energy Technology Data Exchange (ETDEWEB)

    Debus, Alexander

    2012-09-06

    This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

  15. 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

  16. Determination of spallation residues in thin target: toward an hybrid reactor lead target simulation

    International Nuclear Information System (INIS)

    Audouin, L.; Tassan-Got, L.; Bernas, M.; Rejmund, F.; Stephan, C.; Taieb, J.; Boudard, A.; Fernandez, B.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W.; Benlliure, J.; Casajeros, E.; Pereira, J.; Czajkowski, S.

    2001-01-01

    The production of spallation primary residual nuclei in thin target has been studied by measurement of isotopic yields distributions for several systems. Issues relevant for the design of accelerator-driven systems are presented. Monte-Carlo code abilities to reproduce data are studied in details; it is shown that calculations do not reproduce data in a satisfactory way. Future work orientations leading to an improvement of thin targets calculations and ultimately to a thick target simulation are discussed. (author)

  17. SUPER-FMIT, an accelerator-based neutron source for fusion components irradiation testing

    International Nuclear Information System (INIS)

    Burke, R.J.; Holmes, J.J.; Johnson, D.L.; Mann, F.M.; Miles, R.R.

    1984-01-01

    The SUPER-FMIT facility is proposed as an advanced accelerator based neutron source for high flux irradiation testing of large-sized fusion reactor components. The facility would require only small extensions to existing accelerator and target technology originally developed for the Fusion Materials Irradiation Test (FMIT) facility. There, neutrons would be produced by a 0.1 ampere beam of 35 MeV deuterons incident upon a liquid lithium target. The volume available for high flux (> 10 14 n/cm 2 -s) testing in SUPER-FMIT would be 14 liters, about a factor of 30 larger than in the FMIT facility. This is because the effective beam current of 35 MeV deuterons on target can be increased by a factor of ten to 1.0 amperes or more. Such a large increase can be accomplished by acceleration of multiple beams of molecular deuterium ions (D 2 +) to 70 MeV in a common accelerator sructure. The availability of multiple beams and large total current allows great variety in the testing that can be done. For example, fluxes greater than 10 16 n/cm 2 -s, multiple simultaneous experiments, and great flexibility in tailoring of spatial distributions of flux and spectra can be achieved

  18. Modeling high-Power Accelerators Reliability-SNS LINAC (SNS-ORNL); MAX LINAC (MYRRHA)

    Energy Technology Data Exchange (ETDEWEB)

    Pitigoi, A. E.; Fernandez Ramos, P.

    2013-07-01

    Improving reliability has recently become a very important objective in the field of particle accelerators. The particle accelerators in operation are constantly undergoing modifications, and improvements are implemented using new technologies, more reliable components or redundant schemes (to obtain more reliability, strength, more power, etc.) A reliability model of SNS (Spallation Neutron Source) LINAC has been developed within MAX project and analysis of the accelerator systems reliability has been performed within the MAX project, using the Risk Spectrum reliability analysis software. The analysis results have been evaluated by comparison with the SNS operational data. Results and conclusions are presented in this paper, oriented to identify design weaknesses and provide recommendations for improving reliability of MYRRHA linear accelerator. The SNS reliability model developed for the MAX preliminary design phase indicates possible avenues for further investigation that could be needed to improve the reliability of the high-power accelerators, in view of the future reliability targets of ADS accelerators.

  19. Progress at the pulsed-spallation neutron facility KENS

    International Nuclear Information System (INIS)

    Watanabe, N.

    1989-01-01

    The world's smallest pulsed-spallation neutron facility KENS is still active and has been successfully operated since 1986 with increasing proton-beam intensity. Scientists of the proton accelerator group at KEK have convinced themselves that a beam intensity of 2 x 10 12 protons per pulse came within range. The beam time allocated to neutron-scattering experiments was about 1150 hours per year. Visiting scientists spent about 3500 man-days at the KENS facility in the last year from about 40 different institutes to perform experiments. Details given about the KENS neutron facility include the number of experiment proposals, the beam-time distribution of each instrument used in various research fields, the number of scientists and engineers in the Booster Synchrotron Utilization Facility and the number of research publications each year. Improvements and highlights of the research undertaken are noted. (author)

  20. Proposed second harmonic acceleration system for the intense pulsed neutron source rapid cycling synchrotron

    International Nuclear Information System (INIS)

    Norem, J.; Brandeberry, F.; Rauchas, A.

    1983-01-01

    The Rapid Cycling Synchrotron (RCS) of the Intense Pulsed Neutron Source (IPNS) operating at Argonne National Laboratory is presently producing intensities of 2 to 2.5 x 10 12 protons per pulse (ppp) with the addition of a new ion source. This intensity is close to the space charge limit of the machine, estimated at approx.3 x 10 12 ppp, depending somewhat on the available aperture. With the present good performance in mind, accelerator improvements are being directed at: (1) increasing beam intensities for neutron science; (2) lowering acceleration losses to minimize activation; and (3) gaining better control of the beam so that losses can be made to occur when and where they can be most easily controlled. On the basis of preliminary measurements, we are now proposing a third cavity for the RF systems which would provide control of the longitudinal bunch shape during the cycle which would permit raising the effective space charge limit of the accelerator and reducing losses

  1. Development of exploding wire ion source for intense pulsed heavy ion beam accelerator

    International Nuclear Information System (INIS)

    Ochiai, Y.; Murata, T.; Ito, H.; Masugata, K.

    2012-01-01

    A Novel exploding wire type ion source device is proposed as a metallic ion source of intense pulsed heavy ion beam (PHIB) accelerator. In the device multiple shot operations is realized without breaking the vacuum. The basic characteristics of the device are evaluated experimentally with an aluminum wire of diameter 0.2 mm, length 25 mm. Capacitor bank of capacitance 3 μF, charging voltage 30 kV was used and the wire was successfully exploded by a discharge current of 15 kA, rise time 5.3 μs. Plasma flux of ion current density around 70 A/cm 2 was obtained at 150 mm downstream from the device. The drift velocity of ions evaluated by a time-of-flight method was 2.7x10 4 m/sec, which corresponds to the kinetic energy of 100 eV for aluminum ions. From the measurement of ion current density distribution ion flow is found to be concentrated to the direction where ion acceleration gap is placed. From the experiment the device is found to be acceptable for applying PHIB accelerator. (author)

  2. Developing field emission electron sources based on ultrananocrystalline diamond for accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Baryshev, Sergey V.; Jing, Chunguang; Qiu, Jiaqi; Antipov, Sergey; Jabotinski, Vadim; Shao, Jiahang; Gai, Wei; Sumant, Anirudha V.

    2016-08-25

    Radiofrequency (RF) electron guns work by establishing an RF electromagnetic field inside a cavity having conducting walls. Electrons from a cathode are generated in the injector and immediately become accelerated by the RF electric field, and exit the gun as a series of electron bunches. Finding simple solutions for electron injection is a long standing problem. While energies of 30-50 MeV are achievable in linear accelerators (linacs), finding an electron source able to survive under MW electric loads and provide an average current of 1-10 mA is important. Meeting these requirements would open various linac applications for industry. The natural way to simplify and integrate RF injector architectures with the electron source would be to place the source directly into the RF cavity with no need for additional heaters/lasers. Euclid TechLabs in collaboration with Argonne National Lab are prototyping a family of highly effective field emission electron sources based on a nitrogen-incorporated ultrananocrystalline diamond ((N)UNCD) platform. Determined metrics suggest that our emitters are emissive enough to meet requirements for magnetized cooling at electron-ion colliders, linac-based radioisotope production and X-ray sterilization, and others.

  3. Long-term storage life of light source modules by temperature cycling accelerated life test

    International Nuclear Information System (INIS)

    Sun Ningning; Tan Manqing; Li Ping; Jiao Jian; Guo Xiaofeng; Guo Wentao

    2014-01-01

    Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope (IFOG). While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG. (semiconductor devices)

  4. Multicriterial evaluation of spallation reaction models

    International Nuclear Information System (INIS)

    Andrianov, A.A.; Gritsyuk, S.V.; Korovin, Yu.A.; Kuptsov, I.S.

    2013-01-01

    Results of evaluation of predicting ability of spallation reaction models as applied to high-energy protons interaction based on methods of discrete decision analysis are presented. It is shown that results obtained using different methods are well consistent. Recommendations are given on the use of discrete decision analysis methods for providing constants to be employed in calculations of future nuclear power facility [ru

  5. Design and validation of an accelerator for an ultracold electron source

    Directory of Open Access Journals (Sweden)

    G. Taban

    2008-05-01

    Full Text Available We describe here a specially designed accelerator structure and a pulsed power supply that are essential parts of a high brightness cold atoms-based electron source. The accelerator structure allows a magneto-optical atom trap to be operated inside of it, and also transmits subnanosecond electric field pulses. The power supply produces high voltage pulses up to 30 kV, with a rise time of up to 30 ns. The resulting electric field inside the structure is characterized with an electro-optic measurement and with an ion time-of-flight experiment. Simulations predict that 100 fC electron bunches, generated from trapped atoms inside the structure, reach an emittance of 0.04 mm mrad and a bunch length of 80 ps.

  6. Diffusive shock acceleration in the lobes of the Serpens triple radio source

    Energy Technology Data Exchange (ETDEWEB)

    Crusius-Watzel, A.R. (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA))

    1990-10-01

    Recent observations of the triple radio source in the Serpens star formation region have shown large proper motions of the lobes. Their radio spectral index is characteristic of nonthermal emission. The possibility that this is synchrotron radiation from relativistic electrons is investigated. Particle acceleration can occur at the bow shock (bullet and jet model) or at the jet termination shock. The rates for ion-neutral damping and for the self-excitation of magnetic field fluctuations are compared. High levels of MHD turbulence and/or high Alfvenic Mach numbers are required to produce a power-law energy spectrum of electrons up to Lorentz factors of 1000. Diffusive shock acceleration of particles is then very efficient. 26 refs.

  7. Status of the Advanced Photon Source and its accelerator control system

    International Nuclear Information System (INIS)

    McDowell, W.; Knott, M.; Kraimer, K.M.

    1993-01-01

    This paper presents the current status of the Advanced Photon Source (APS), its control system and the Experimental Physics and Industrial Control System (EPICS) tools being used to implement this control system. The status of the physical plant and each of the accelerators as well as detailed descriptions of the software tools used to build the accelerator control system are presented. The control system uses high-performance graphic workstations and the X-windows graphical user interface (GUI) at the operator interface level. It connects to VME/VXI-based microprocessors at the field level using TCP/IP protocols over high-performance networks. This strategy assures the flexibility and expansibility of the control system. A defined interface between the system components will allow the system to evolve with the direct addition of future, improved equipment and new capabilities

  8. Results of adjustment of electron source for the LIU-30 accelerator

    International Nuclear Information System (INIS)

    Androsov, A.V.; Kladnitskij, V.S.; Platonov, S.L.; Shvets, V.A.

    1988-01-01

    A new design of an electron source (electron gun) for the LIU-30 accelerator is described. Unlike the earlier used ones it has been made as a separate unit connected via a special adapter with increasing pulsed 300 kW transformer constructed on the base of an accelerating section. Ferromagnetic screen of a special shape and antisolenoid placed behind the cathode in a hollow of an oil-filled insulator and switched on antiparallely to the main focusing solenoid permit to diminish the gun emittance by 10-15%due to zero magnetic field in the cathode region. Various electron-optical systems were tested and that one based on the Pierse gun in which the anode orifice was covered with a wire gauze with 2.5 mm cell was chosen. 3 refs.; 1 fig

  9. Research of accelerator-based neutron source for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Li Changkai; Ma Yingjie; Tang Xiaobin; Xie Qin; Geng Changran; Chen Da

    2013-01-01

    Background: 7 Li (p, n) reaction of high neutron yield and low threshold energy has become one of the most important neutron generating reactions for Accelerator-based Boron Neutron Capture Therapy (BNCT). Purpose Focuses on neutron yield and spectrum characteristics of this kind of neutron generating reaction which serves as an accelerator-based neutron source and moderates the high energy neutron beams to meet BNCT requirements. Methods: The yield and energy spectrum of neutrons generated by accelerator-based 7 Li(p, n) reaction with incident proton energy from 1.9 MeV to 3.0 MeV are researched using the Monte Carlo code-MCNPX2.5.0. And the energy and angular distribution of differential neutron yield by 2.5-MeV incident proton are also given in this part. In the following part, the character of epithermal neutron beam generated by 2.5-MeV incident protons is moderated by a new-designed moderator. Results: Energy spectra of neutrons generated by accelerator-based 7 Li(p, n) reaction with incident proton energy from 1.9 MeV to 3.0 MeV are got through the simulation and calculation. The best moderator thickness is got through comparison. Conclusions: Neutron beam produced by accelerator-based 7 Li(p, n) reaction, with the bombarding beam of 10 mA and the energy of 2.5 MeV, can meet the requirement of BNCT well after being moderated. (authors)

  10. Narrow bandwidth Laser-Plasma Accelerator driven Thomson photon source development

    Science.gov (United States)

    Geddes, C. G. R.; Tsai, H.-E.; Otero, G.; Liu, X.; van Tilborg, J.; Toth, Cs.; Vay, J.-L.; Lehe, R.; Schroeder, C. B.; Esarey, E.; Friedman, A.; Grote, D. P.; Leemans, W. P.

    2017-10-01

    Compact, high-quality photon sources at MeV energies can be provided by Thomson scattering of a laser from the electron beam of a Laser-Plasma Accelerator (LPA). Recent experiments and simulations demonstrate controllable LPAs in the energy range appropriate to MeV sources. Simulations indicate that high flux with narrow energy spread can be achieved via control of the scattering laser pulse shape and laser guiding, and that undesired background bremsstrahlung can be mitigated by plasma based deceleration of the electron beam after photon production. Construction of experiments and laser capabilities to combine these elements will be presented, along with initial operations, towards a compact photon source system. Work supported by US DOE NNSA DNN R&D and by Sc. HEP under contract DE-AC02-05CH11231.

  11. An ECR ion source-based low-energy ion accelerator: development and performance

    Science.gov (United States)

    Agnihotri, A. N.; Kelkar, A. H.; Kasthurirangan, S.; Thulasiram, K. V.; Desai, C. A.; Fernandez, W. A.; Tribedi, L. C.

    2011-06-01

    Electron cyclotron resonance (ECR) ion sources produce low-energy, highly charged ions. A new 14.5 GHz ECR-based low-energy ion accelerator facility has been developed. The ion source involves a plasma chamber ('supernanogan') surrounded by permanent magnets that provide a suitable magnetic field. The entire assembly including the ion source and the analyzing magnet is mounted on a 400 kV deck. A LabVIEW-based command and control system has been developed for the beamline. In addition, wireless communication has been installed to operate the machine in high voltage. The charge state distribution of several ions (He, N2, O2, Ne, Ar and Xe) has been measured. For Ar and Xe, the maximum charge states measured were 16+ and 29+, respectively. A direct x-ray measurement for plasma diagnostics was also initiated.

  12. An ECR ion source-based low-energy ion accelerator: development and performance

    Energy Technology Data Exchange (ETDEWEB)

    Agnihotri, A N; Kelkar, A H; Kasthurirangan, S; Thulasiram, K V; Desai, C A; Fernandez, W A; Tribedi, L C, E-mail: lokesh@tifr.res.in [Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2011-06-15

    Electron cyclotron resonance (ECR) ion sources produce low-energy, highly charged ions. A new 14.5 GHz ECR-based low-energy ion accelerator facility has been developed. The ion source involves a plasma chamber ('supernanogan') surrounded by permanent magnets that provide a suitable magnetic field. The entire assembly including the ion source and the analyzing magnet is mounted on a 400 kV deck. A LabVIEW-based command and control system has been developed for the beamline. In addition, wireless communication has been installed to operate the machine in high voltage. The charge state distribution of several ions (He, N{sub 2}, O{sub 2}, Ne, Ar and Xe) has been measured. For Ar and Xe, the maximum charge states measured were 16{sup +} and 29{sup +}, respectively. A direct x-ray measurement for plasma diagnostics was also initiated.

  13. Gpufit: An open-source toolkit for GPU-accelerated curve fitting.

    Science.gov (United States)

    Przybylski, Adrian; Thiel, Björn; Keller-Findeisen, Jan; Stock, Bernd; Bates, Mark

    2017-11-16

    We present a general purpose, open-source software library for estimation of non-linear parameters by the Levenberg-Marquardt algorithm. The software, Gpufit, runs on a Graphics Processing Unit (GPU) and executes computations in parallel, resulting in a significant gain in performance. We measured a speed increase of up to 42 times when comparing Gpufit with an identical CPU-based algorithm, with no loss of precision or accuracy. Gpufit is designed such that it is easily incorporated into existing applications or adapted for new ones. Multiple software interfaces, including to C, Python, and Matlab, ensure that Gpufit is accessible from most programming environments. The full source code is published as an open source software repository, making its function transparent to the user and facilitating future improvements and extensions. As a demonstration, we used Gpufit to accelerate an existing scientific image analysis package, yielding significantly improved processing times for super-resolution fluorescence microscopy datasets.

  14. Characterisation of an accelerator-based neutron source for BNCT versus beam energy

    CERN Document Server

    Agosteo, S; D'Errico, F; Nath, R; Tinti, R

    2002-01-01

    Neutron capture in sup 1 sup 0 B produces energetic alpha particles that have a high linear energy transfer in tissue. This results in higher cell killing and a higher relative biological effectiveness compared to photons. Using suitably designed boron compounds which preferentially localize in cancerous cells instead of healthy tissues, boron neutron capture therapy (BNCT) has the potential of providing a higher tumor cure rate within minimal toxicity to normal tissues. This clinical approach requires a thermal neutron source, generally a nuclear reactor, with a fluence rate sufficient to deliver tumorcidal doses within a reasonable treatment time (minutes). Thermal neutrons do not penetrate deeply in tissue, therefore BNCT is limited to lesions which are either superficial or otherwise accessible. In this work, we investigate the feasibility of an accelerator-based thermal neutron source for the BNCT of skin melanomas. The source was designed via MCNP Monte Carlo simulations of the thermalization of a fast ...

  15. Accelerator technical design report for high-intensity proton accelerator facility project, J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-03-01

    This report presents the detail of the technical design of the accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC. The accelerator complex comprises a 400-MeV room-temperature linac (600-MeV superconducting linac), 3-GeV rapid-cycling synchrotron (RCS), and a 50-GeV synchrotron (MR). The 400-MeV beam is injected to the RCS, being accelerated to 3 GEV. The 1-MW beam thus produced is guided to the Materials Life Science Experimental Facility, with both the pulsed spallation neutron source and muon source. A part of the beam is transported to the MR, which provides the 0.75-MW beam to either the Nuclear and Fundamental Particle Experimental Facility or the Neutrino Production Target. On the other hand, the beam accelerated to 600 MeV by the superconducting linac is used for the Nuclear Waster Transmutation Experiment. In this way, this facility is unique, being multipurpose one, including many new inventions and Research and Development Results. This report is based upon the accomplishments made by the Accelerator Group and others of the Project Team, which is organized on the basis of the Agreement between JAERI and KEK on the Construction and Research and Development of the High-Intensity Proton Accelerator Facility. (author)

  16. ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS

    International Nuclear Information System (INIS)

    Wei, J.; Macek, R.J.

    2002-01-01

    One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures

  17. ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; MACEK,R.J.

    2002-04-14

    One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures.

  18. Summary talk - an accelerator for other projects

    International Nuclear Information System (INIS)

    Laclare, J.L.

    2001-01-01

    Over the past few years, great consideration was given to the feasibility of a new generation of high intensity proton linear accelerators capable of delivering several tens of MW of beam power. Many scientific applications could benefit from such a development: 1) hybrid reactors and transmutation of nuclear waste, 2) muon and neutrino factories, 3) irradiation tools, 4) spallation neutron source for material studies, 5) radioactive nuclear beams, and 6) radioisotopes. Deciding on priorities is more difficult than in the past and competition is extremely strong. A possible solution could be to look for possible synergies between these projects and to develop multi-purpose facilities whenever the applications are compatible, so as to maximize scientific outcome while minimising costs. This paper intends to identify large similarities in terms of accelerator requirements and potential synergies for the 6 applications listed above

  19. Reactor - and accelerator-based filtered beams

    International Nuclear Information System (INIS)

    Mill, A.J.; Harvey, J.R.

    1980-01-01

    The neutrons produced in high flux nuclear reactors and in accelerator, induced fission and spallation reactions, represent the most intense sources of neutrons available for research. However, the neutrons from these sources are not monoenergetic, covering the broad range extending from 10 -3 eV up to 10 7 eV or so. In order to make quantitative measurements of the effects of neutrons and their dependence on neutron energy it is desirable to have mono-energetic neutron sources. The paper describes briefly methods of obtaining mono-energetic neutrons and different methods of filtration. This is followed by more detailed discussion of neutron window filters and a summary of the filtered beam facilities using this technique. The review concludes with a discussion of the main applications of filtered beams and their present and future importance

  20. Measurements of the thermal neutron flux for an accelerator-based photoneutron source.

    Science.gov (United States)

    Taheri, Ali; Pazirandeh, Ali

    2016-12-01

    To have access to an appropriate neutron source is one of the most demanding requirements for neutron studies. This is important specially in laboratory and clinical applications, which need more compact and accessible sources. The most known neutron sources are fission reactors and natural isotopes, but there is an increasing interest for using accelerator based neutron sources because of their advantages. In this paper, we shall present a photo-neutron source prototype which is designed and fabricated to be used for different neutron researches including in-laboratory neutron activation analysis and neutron imaging, and also preliminary studies in boron neutron capture therapy (BNCT). Series of experimental tests were conducted to examine the intensity and quality of the neutron field produced by this source. Monte-Carlo simulations were also utilized to provide more detailed evaluation of the neutron spectrum, and determine the accuracy of the experiments. The experiments demonstrated a thermal neutron flux in the order of 10 7 (n/cm 2 .s), while simulations affirmed this flux and showed a neutron spectrum with a sharp peak at thermal energy region. According to the results, about 60 % of produced neutrons are in the range of thermal to epithermal neutrons.